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THE UNIVERSE- WHAT IS BEYOND THE UNIVERSE? THE UNIVERSE AND BEYOND


The Universe - How the Universe was formed-The Universe Planets


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WHAT IS BEYOND THE UNIVERSE?


The Universe Videos | Masters of The Universe Revelation Videos | The Universe Images from The Hubble Telescope


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  • Beyond the Observable Universe
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  • What is beyond the edge of the Universe?
  • Is there anything beyond the Universe?
  • What is bigger than Universe?
  • Could we see beyond the Universe?



Is the Universe Infinite - The Universe Explained­ - The Universe in a Nutshell


The Universe Solar Rules

Guys, here we will discuss about The Universe and Solar System, The Universe Planets, The Universe Images, The Universe Map, How the Universe Works, How the Universe was Formed, the Universe definition, the Universe Planets, the Universe Expanding, How the Universe was created, Where the Universe came from Book and the Universe Video-The Universe YouTube Videos for some competitive examination purpose and knowledge of our planet where we live and breathe.



We have mentioned below in this article about all activities happening in our Universe.



The Universe Images





Friends, here are many questions arising in your mind about the Universe and its functions. We have collected many data and questions with answers for your examination purpose.




New Earth - Sized Planet Found On a Nearby Star



Watch The New Habitable Exoplanet K2-18b



Dear friends, NASA found a new habitable exoplanet 11 light years away from earth. This planet is same as earth in properties and has same surface gravity and atmosphere. Watch this new exoplanet video for more information here.



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Is The Universe Infinite? Questionnaires

What is Universe, short answer?
Guys, the Universe is everything we can touch, feel, sense, measure or detect. It includes living things, Planets, Stars, galaxies, dust clouds, light and even time. Before the birth of the Universe, time, space and matter did not exist.


Why is water wet?

Being a liquid, water is not itself wet, but can make other solid materials wet. Wetness is the ability of a liquid to adhere to the surface of a solid, so when we say that something is wet; we mean that the liquid is sticking to the surface of a material. Cohesive forces are also responsible for surface tension.

What defines a Universe?


Guys,the Universe is the whole of all matter, energy, Planets, galaxies and space. An example of Universe is where everyone and everything exists. Your Dictionary Definition and usage example.


How big is the Universe?


The observable Universe is, of course, much larger. According to current thinking it is about 93 billion light years in diameter.

Could the Universe be inside a black hole?


The seed this mother Universe forged inside a black hole may have had its big bounce 13.8 billion years ago, and even though our Universe has been rapidly expanding ever since, we could still be hidden behind a black hole's event horizon.

Is there dry water?


Guys, dry water, an unusual form of "powdered liquid", is a water–air emulsion in which tiny water droplets, each the size of a grain of sand, are surrounded by a sandy silica coating. It is also more commonly known among researchers as empty water.

What is beyond the Universe?


The Universe is a vast expanse of space which contains all of everything in existence. The Universe contains all of the galaxies, Stars, and Planets. The exact Size of the Universe is unknown. Scientists believe the Universe is still expanding outwards.

Will the Universe end?


The geometry of   the Universe is, at least on a very large Scale, elliptic. In a closed Universe, gravity eventually stops the expansion of the Universe, after which it starts to contract until all matter in   the Universe collapses to a point; a final singularity termed the "Big Crunch", the opposite of the Big Bang.

How long will the Universe last?


The Universe will cease to exist around the same time our sun is slated to die, according to new predictions based on the multiverse theory. Our Universe has existed for nearly 14 billion years, and as far as most people are concerned, the Universe should continue to exist for billions of years more.

What is the main theory on How the Universe Was formed?


The prevailing model for the evolution of the Universe is the Big Bang   theory. The Big Bang model states that the earliest state of the Universe was an extremely hot and dense one and that the Universe subsequently expanded and cooled.

How big is the Universe beyond the observable Universe?


The radius of the observable Universe is therefore estimated to be about 46.5 billion light-years and its diameter about 28.5 gig parsecs (93 billion light-years, 8.8×1023 kilometers or 5.5×1023 miles).

How long until the earth ends?


Thus plants using C4 Photosynthesis may be able to survive for at least 0.8 billion years and possibly as long as 1.2 billion years from now, after which rising temperatures will make the biosphere unsustainable. Currently, C4 plants represent about 5% of Earth's plant biomass and 1% of its known plant species.

How fast is the Universe Expanding?


Guys, in 2001, Dr. Wendy Freedman determined space to expand at 72 kilometers per second per mega parsec - roughly 3.3 million light years - meaning that for every 3.3 million light years further away from the earth you are, the matter where you are, is moving away from earth 72 kilometers a second faster.

What lies inside a black hole?


At the center of a black hole, as described by general relativity, may lie a gravitational singularity, a region where the space time curvature becomes Infinite.

Will a black hole kill us?


In the previous case objects would actually be destroyed and people killed by  the heat, not   the tidal forces - but near a black hole (assuming that there is no nearby matter), objects would actually be destroyed and people killed by the tidal forces, because there is no radiation.

What is a white hole NASA?


In general relativity, a white hole is a hypothetical region of space time which cannot be entered from the outside, although matter and light can escape from it. In this sense, it is the reverse of a black hole, which can only be entered from the outside and from which matter and light cannot escape.

What is beyond the outer space?


Outer space, or just space, is the expanse that exists beyond the Earth and between celestial bodies. Intergalactic space takes up most of the volume of  the Universe, but even galaxies and Star Systems consist almost entirely of empty space.

What is the Big Rip theory?


Guys, in physical cosmology, the Big Rip is a hypothetical cosmological model concerning the ultimate fate of the Universe, in which the matter of the Universe, from Stars and galaxies to atoms and subatomic particles, and even space-time itself, is progressively torn apart by the expansion of the Universe at a certain time.

Is the Universe flat?


In a Universe with zero curvature, the local geometry is flat. The most obvious global structure is that of Euclidean space, which infinite in extent is. Flat Universes that are finite in extent include the torus and Klein bottle.

What will happen to Universe in future?

Observations suggest that the expansion of the Universe will continue forever. If so, then a popular theory is that the Universe will cool as it expands, eventually becoming too cold to sustain life. For this reason, this future scenario once popularly called "Heat Death" is now known as the Big Chill or Big Freeze.






How was Earth Created?


The Earth formed around 4.54 billion years ago, approximately one-third   the age of the Universe, by accretion from the Solar nebula. Volcanic outgassing probably created the primordial atmosphere and then the ocean, but the early atmosphere contained almost no oxygen.

How big is the Universe in simple terms?


It is estimated that the age of the Universe is 13.73 (± 0.12) billion years, and that the diameter of the Universe is at least 93 billion light years or 8.80×1026 meters.

What happens to a human body in space?


Guys,in space, astronauts lose fluid volume-including up to 22% of their blood volume. Because it has less blood to pump, the heart will atrophy. When gravity is taken away or reduced during space exploration, the blood tends to collect in the upper body instead, resulting in facial edema and other unwelcome side effects.

How many galaxies are there in the Milky Way?


25,000 crores ± 15,000 crores

What is the observable Universe called?


In Big Bang cosmology, the observable Universe is what, in theory, can be seen from Earth. That is light, or other signals, which has had time to reach the Earth since the beginning of the cosmological expansion. Before then, the Universe was filled with plasma that was opaque to Photons.

How long till Earth is overpopulated?


Depending on which estimate is used, human overpopulation may or may not have already occurred. Nevertheless the rapid recent increase in human population is causing some concern. The population is expected to reach between 8 and 10.5 billion between the years 2040 and 2050.

How long till Earth is overpopulated?


Friends, depending on which estimate is used, human overpopulation may or may not have already occurred. Nevertheless, the rapid recent increase in human population is causing some concern. The population is expected to reach between 8 and 10.5 billion between the years 2040 and 2050.





How will the Universe end?


The geometry of the Universe is, at least on a very large Scale, elliptic. In a closed Universe, gravity eventually stops the expansion of the Universe, after which it starts to contract until all matter in the Universe collapses to a point; a final singularity termed the "Big Crunch", the opposite of the Big Bang.

Is the Universe Infinite?


Because we cannot observe space beyond the edge of the observable Universe, it is unknown whether the Size of the Universe in its totality is finite or infinite.

Where is black hole located?


Guys, observational evidence indicates that nearly all large galaxies contain a supermassive black hole, located at the galaxy's center. In the case of the Milky Way, the supermassive black hole corresponds to the location of Sagittarius A* at the Galactic Core.

Why is it called space time?


The Space-time is a mathematical model that joins space and time into a single idea called a continuum. This four-dimensional continuum is known as Murkowski space. This is because the observed rate at which time passes depends on an object's velocity relative to the observer.

Do black holes emit radiation?


Hawking showed that quantum effects allow black holes to emit exact black-body radiation. As the particle–antiparticle pair was produced by the black hole's gravitational energy, the escape of one of the particles lowers the mass of the black hole.

Is there a black hole near the earth?


This list contains all known black holes relatively near the Solar System (within our Milky Way galaxy). To make it easier to compare distances, our nearest Star aside from the Sun - Proxima Centauri – is about 4.24 light years away and our Milky Way galaxy is 180,000 light years in diameter.

Who found black hole?


Guys, the first modern solution of general relativity that would characterize a black hole was found by Karl Schwarzschild in 1916, although its interpretation as a region of space from which nothing can escape was first published by David Finkelstein in 1958.

What happens when two black holes collide?


Friends, when two galaxies collide, the supermassive black holes at their centers do not hit head-on, but would shoot past each other on hyperbolic trajectories if some mechanism did not bring them together. As a black hole passes a Star, the gravitational slingshot accelerates the Star while decelerating the black hole.


Are black holes actually dark energy Stars?


Theory- In March 2005, physicist George Chaplin claimed that quantum mechanics makes it a "near certainty" that black holes do not exist and are instead dark-energy Stars. The dark-energy Star is a different concept from that of a Grava Star.

Is there an edge of the Universe?


The commoving distance from Earth to the edge of the observable Universe is about 14.26 gig parsecs (46.5 billion light-years or 4.40×1026 meters) in any direction. The observable Universe is thus a sphere with a diameter of about 28.5 gig parsecs (93 billion light-years or 8.8×1026 meters).





Is there life on Mars?


Guys, impactite, shown to preserve signs of life on Earth, was discovered on Mars and could contain signs of ancient life, if life ever existed on the planet. On June 7, 2018, NASA announced that the Curiosity rover had discovered organic molecules in sedimentary rocks dating to three billion years old.

How far away is   the heat death of   the Universe?


This is the timeline of the Universe from Big Bang to Heat Death scenario. The different eras of the Universe are shown. The heat death will occur in 10100 years, if protons decay.

Is space curved?


Friends, curved space often refers to a spatial geometry which is not "flat" where a flat space is described by Euclidean geometry. Curved spaces can generally be described by Riemannian geometry though some simple cases can be described in other ways.

Is space a 3d?


A four-dimensional space or 4D space is a mathematical extension of the concept of three-dimensional or 3D space. Three-dimensional space is the simplest possible abstraction of the observation that one only needs three numbers, called dimensions, to describe the Sizes or locations of objects in the everyday world.

What is in a parallel Universe?


A parallel Universe, also known as an alternate Universe or alternate reality, is a hypothetical self-contained reality co-existing with one's own. A specific group of parallel Universes are called a "multiverse", although this term can also be used to describe the possible parallel Universes that constitute reality.

Do black holes create new Universes?


According to general relativity, the gravitational collapse of a sufficiently compact mass forms a singular Schwarzschild black hole. In the Einstein–Cartan–Sciama–Kibble theory of gravity, however, it forms a regular Einstein–Rosen bridge, or wormhole.

What is the Black Hole Era?


The Black Hole Era is defined as "40 < n < 100". In this era, according to   the Book, organized matter will remain only in the form of black holes. Black holes themselves slowly "evaporate" away the matter contained in them, by the quantum mechanical process of Hawking radiation.


Who Created earth?

The Earth formed around 4.54 billion years ago, approximately one-third the age of the Universe, by accretion from the Solar nebula. Volcanic outgassing probably created the primordial atmosphere and then the ocean, but the early atmosphere contained almost no oxygen.





Is the Universe flat?


Guys, in the Universe with zero curvature, the local geometry is flat. The most obvious global structure is that of Euclidean space, which infinite in extent is. Flat Universes that are finite in extent include the torus and Klein bottle.

Are there dead bodies in space?


As of 2018, there have been 14 astronaut and 4 cosmonaut fatalities during spaceflight. Astronauts have also died while training for space missions, such as the Apollo 1 launch pad fire which killed an entire crew of three.

Can you breathe on Mars?


Friends, However, the surface is not hospitable to humans or most known life forms due to the radiation, greatly reduced air pressure and an atmosphere with only 0.1% oxygen. Humans have explored parts of Earth that match some conditions on Mars.

Are there 2 trillion galaxies?


XDF (2012) view: Each light speck is a galaxy, some of which are as old as 13.2 billion years – the observable Universe is estimated to contain 200 billion to 2 trillion galaxies.

What is our Milky Way?


The Milky Way is the galaxy that contains the Solar System. The Milky Way is a barred spiral galaxy with a diameter between 150,000 and 200,000 light-years (ly). It is estimated to contain 100–400 billion Stars and more than 100 billion Planets.

How vast is the Universe?


Friends, while the spatial Size of the entire Universe is unknown, it is possible to measure the Size of the observable Universe, which is currently estimated to be 93 billion light-years in diameter.

Is Earth the center of the observable Universe?


Because the observable Universe is defined as that region of the Universe visible to terrestrial observers, Earth is, because of the constancy of the speed of light, the center of Earth's observable Universe.

What happens to a human body in space?


In the space, astronauts lose fluid volume-including up to 22% of their blood volume. Because it has less blood to pump, the heart will atrophy. When gravity is taken away or reduced during space exploration, the blood tends to collect in the upper body instead, resulting in facial edema and other unwelcome side effects.





Can we live forever?


Guys, DYING is an inevitable part of life and there is no way humans will be able to biologically live forever, scientists have confirmed. But now, experts say they have conclusive proof there is no way to stop ageing and humans are born to die.

Can the human brain live forever?


Friends, but just because brain cells may be able to live indefinitely doesn't mean humans could live forever. Aging is dependent on more than the life span of all the individual parts in the body, and scientists still don't understand exactly what causes people to age, Magrassi said.


About the Universe


Universe Information


Guys, for word about the Universe, are all of space and time and   their contents including Planets, Stars, Galaxies, and all other forms of matter and energy. While the spatial Size of the entire Universe is unknown, it is possible to measure the Size of the observable Universe, which is currently estimated to be 93 billion light-years in diameter. In various multiverse hypotheses, a Universe is one of many causally disconnected constituent parts of a larger multiverse, which itself comprises all of space and time and its contents.


In the earliest cosmological models of the Universe were developed by ancient Greek and Indian philosophers and were geocentric, placing Earth at the center. Over the centuries, more precise astronomical observations led Nicolaus Copernicus to develop the heliocentric model with the Sun at the center of the Solar System. In developing the law of universal gravitation, Isaac Newton built upon Copernicus' work as well as Johannes Kepler's laws of planetary motion and observations by Tycho Brahe.


The Universe
The Universe

Friends, than onward further observational improvements led to the realization that   the Sun is one of hundreds of billions of Stars in the Milky Way, which is one of at least hundreds of billions of galaxies in the Universe. Many of the Stars in our galaxy have Planets. At the largest Scale, galaxies are distributed uniformly and the same in all directions, meaning that the Universe has neither an edge nor a center. At smaller Scales, galaxies are distributed in clusters and superclusters which form immense filaments and voids in space, creating a vast foam-like structure. Discoveries in the early 20th century have suggested that the Universe had a beginning and that space has been Expanding since then and is currently still Expanding at an increasing rate.


The Universe
The Universe

Guys, As per the Big Bang theory, the prevailing cosmological description of the development of the Universe. Under this theory, space and time emerged together 13.799±0.021 billion years ago and the energy and matter initially present have become less dense as the Universe expanded. After an initial accelerated expansion called the inflationary epoch at around 10−32 seconds, and the separation of the four known fundamental forces, the Universe gradually cooled and continued to expand, allowing the first subatomic particles and simple atoms to form. Dark matter gradually gathered, forming a foam-like structure of filaments and voids under the influence of gravity.

Bunch of Giant clouds of hydrogen and helium were gradually drawn to the places where dark matter was most dense, forming the first galaxies, Stars, and everything else seen today. It is possible to see objects that are now further away than 13.799 billion light-years because space itself has expanded and it is still expanding today. This means that objects which are now up to 46.5 billion light-years away can still be seen in their distant past, because in the past, when their light was emitted, they were much closer to Earth.


The Universe
The Universe

Freinds, from studying the movement of galaxies, it has been discovered that the Universe contains much more matter than is accounted for by visible objects; Stars, galaxies, nebulas and interstellar gas. This unseen matter is known as dark matter (dark means that there is a wide range of strong indirect evidence that it exists, but we have not yet detected it directly). The ΛCDM model is   the most widely accepted model of our Universe. It suggests that about 69.2%± 1.2% of the mass and energy in the Universe is a cosmological constant (or, in extensions to ΛCDM, other forms of dark energy, such as a scalar field) which is responsible for the current expansion of space and about 25.8%±1.1% is dark matter. Ordinary ('baryonic') matter is therefore only 4.84%±0.1% of the physical Universe. Stars, Planets and visible gas clouds only form about 6% of ordinary matter, or about 0.29% of the entire Universe.

Guys, Asper discoveries there are many competing hypo theses about the ultimate fate of the Universe and about what, if anything, preceded the Big Bang, while other physicists and philosophers refuse to speculate, doubting that information about prior states will ever be accessible. Some physicists have suggested various multiverse hypotheses, in which our Universe might be one among many Universes that likewise exist.


The Universe
The Universe


The Characteristic


Friends, here the physical Universe is defined as all of space and time (collectively referred to as space-time) and their contents. Such contents comprise all of energy in its various forms, including electromagnetic radiation and matter, and therefore Planets, Moons, Stars, Galaxies and the Contents of intergalactic space. The Universe also includes the physical laws that influence energy and matter, such as conservation laws, classical mechanics, and relativity.

Now the Universe is often defined as "the totality of existence", or everything that exists, everything that has existed and everything that will exist. In fact, some philosophers and scientists support the inclusion of ideas and abstract concepts-such as mathematics and logic-in the Definition of the Universe. The word Universe may also refer to concepts such as the cosmos, the world, and nature.



About the Universe Fact


How was the Universe Created?


Guys, Founded the prevailing model for the evolution of the Universe is the Big Bang theory. The Big Bang model states that the earliest state of the Universe was an extremely hot and dense one and that the Universe subsequently expanded and cooled. The model is based on general relativity and on simplifying assumptions such as homogeneity and isotropy of space. A version of the model with a cosmological constant (Lambda) and cold dark matter, known as the Lambda-CDM model, is the simplest model that provides a reasonably good account of various observations about the Universe. The Big Bang model accounts for observations such as the correlation of distance and redshift of galaxies, the ratio of the number of hydrogen to helium atoms and the microwave radiation background.




About Planck Epoch


Guys, the initial hot, dense state is called the Planck epoch, a brief period extending from time zero to one Planck time unit of approximately 10−43 seconds. During the Planck epoch, all types of matter and all types of energy were concentrated into a dense state and gravity-currently the weakest by far of   the four known forces-is believed to have been as strong as the other fundamental forces, and all the forces may have been unified. Since the Planck epoch, space has been Expanding to its present Scale, with a very short but intense period of cosmic inflation believed to have occurred within the first 10−32 seconds. This was a kind of expansion different from those we can see around us today. Objects in space did not physically move; instead the metric that defines space itself changed. Although objects in space-time cannot move faster than the speed of light, this limitation does not apply to the metric governing space-time itself. This initial period of inflation is believed to explain why space appears to be very flat, and much larger than light could travel since the Start of the Universe.


The Universe
The Universe

Guys, within the first fraction of a second of the Universe's existence, the four fundamental forces had separated. As the Universe continued to cool down from its inconceivably hot state, various types of subatomic particles were able to form in short periods of time known as the quark epoch, the hadron epoch, and   the lepton epoch. Together, these epochs encompassed less than 10 seconds of time following the Big Bang. These elementary particles associated stably into ever larger combinations, including stable protons and neutrons, which then formed more complex atomic nuclei through nuclear fusion. This process, known as Big Bang nucleosynthesis, only lasted for about 17 minutes and ended about 20 minutes after   the Big Bang, so only the fastest and simplest reactions occurred. About 25% of the protons and all the neutrons in the Universe, by mass, were converted to helium, with small amounts of deuterium (a form of hydrogen) and traces of lithium. Any other element was only formed in very tiny quantities. The other 75% of the protons remained unaffected, as hydrogen nuclei.

When after nucleosynthesis ended, the Universe entered a period known as   the Photon epoch. During this period, the Universe was still far too hot for matter to form neutral atoms, so it contained hot, dense, foggy plasma of negatively charged electrons, neutral neutrinos and positive nuclei. After about 377,000 years, the Universe had cooled enough that electrons and nuclei could form the first stable atoms. This is known as recombination for historical reasons; in fact electrons and nuclei were combining for the first time. Unlike plasma, neutral atoms are transparent to many wavelengths of light, so for the first time the Universe also became transparent. The Photons released ("decoupled") when these atoms formed can still be seen today;  they form the cosmic microwave background (CMB).


The Universe
The Universe

Guys, when the Universe expands, the energy density of electromagnetic radiation decreases more quickly than does that of matter because the energy of a Photon decreases with its wavelength. At around 47,000 years, the energy density of matter became larger than that of Photons and neutrinos, and began to dominate the large Scale behavior of the Universe. This marked the end of the radiation-dominated era and the Start of the matter-dominated era.

In its earliest stages the Universe, tiny fluctuations within the Universe's density led to concentrations of dark matter gradually forming. Ordinary matter, attracted to these by gravity, formed large gas clouds and eventually, Stars and galaxies, where the dark matter was most dense and voids where it was least dense. After around 100 - 300 million years, the first Stars formed, known as Population III Stars. These were probably very massive, luminous, nonmetallic and short-lived. They were responsible for the gradual reionization of the Universe between about 200-500 million years and 1 billion years and also for seeding the Universe with elements heavier than helium, through stellar nucleosynthesis. The Universe also contains a mysterious energy - possibly a scalar field - called dark energy, the density of which does not change over time. After about 9.8 billion years, the Universe had expanded sufficiently so that the density of matter was less than the density of dark energy, marking the beginning of the present dark-energy-dominated era. In this era, the expansion of the Universe is accelerating due to dark energy.


The Universe
The Universe


The Beginning of the Universe


The Big Bang theory is the prevailing cosmological model for the observable Universe from the earliest known periods through its subsequent large-Scale evolution. The model describes How the Universe expanded from a very high-density and high-temperature state and offers a comprehensive explanation for a broad range of phenomena, including the abundance of light elements, the cosmic microwave background (CMB), large-Scale structure and Hubble's law (the farther away galaxies are, the faster they are moving away from Earth). If the observed conditions are extrapolated backwards in time using   the known laws of physics, the prediction is that just before a period of very high density there was a singularity which is typically associated with the Big Bang. Current knowledge is insufficient to determine if the singularity was primordial.


The Universe
The Universe

Guys, Since Georges Lemaitre first noted in 1927 that an Expanding Universe could be traced back in time to an originating single point, scientists have built on his idea of cosmic expansion. The scientific community was once divided between supporters of two different theories, the Big Bang and the steady state theory, but a wide range of empirical evidence has strongly favored the Big Bang which is now universally accepted. In 1929, from analysis of galactic redshifts, Edwin Hubble concluded that galaxies are drifting apart; this is important observational evidence for an Expanding Universe. In 1964, the cosmic microwave background radiation was discovered, which was crucial evidence in favor of the hot Big Bang model since that theory predicted the existence of background radiation throughout the Universe before it was discovered.

Hence the known physical laws of nature can be used to calculate the characteristics of the Universe in detail back in time to an initial state of extreme density and temperature. Detailed measurements of the expansion rate of the Universe place the Big Bang at around 13.8 billion years ago, which is thus considered the age of the Universe. After its initial expansion, the Universe cooled sufficiently to allow the formation of subatomic particles, and later atoms. Giant clouds of these primordial elements (mostly hydrogen, with some helium and lithium) later coalesced through gravity, eventually forming early Stars and galaxies, the descendants of which are visible today.


The Universe
The Universe

Friends, many Astronomers also observe the gravitational effects of dark matter surrounding galaxies. Most of the matter in the Universe seems to be in the form of dark matter, and the Big Bang theory and various observations indicate that it is not conventional baryonic matter (atoms). It is still not known exactly what dark matter is. More recently, measurements of the redshifts of supernovae indicate that the expansion of the Universe is accelerating, an observation attributed to dark energy's existence.

In Year 1922, Russian mathematician Alexander Friedman proposed on   theoretical grounds that the Universe is Expanding, which was rederived independently and observationally confirmed soon afterwards by Belgian astronomer and Catholic priest Georges Lemaitre in 1927 Lemaitre also proposed what became known as the "Big Bang theory" of the creation of the Universe, originally calling it the "hypothesis of the primeval atom" in his paper Annales dela Society Scientifique de Bruxelles (Annals of the Scientific Society of Brussels) under the title "Un Universe homogeny de masse constant et de rayon croissant rendant compte de la vitesse radiale des nebulosus extra galactiques" ("A homogeneous Universe of constant mass and growing radius accounting for the radial velocity of extragalactic nebulae"), he presented his new idea that the Universe is Expanding and provided the first observational estimation of what is known as the Hubble constant. What later will be known as the "Big Bang theory" of the origin of the Universe, he called his "hypothesis of the primeval atom" or the "Cosmic Egg".


The Universe
The Universe

Guys, the American astronomer Edwin Hubble observed that the distances to faraway galaxies were strongly correlated with their redshifts. This was interpreted to mean that all distant galaxies and clusters are receding away from our vantage point with an apparent velocity proportional to their distance: that is, the farther they are, the faster they move away from us, regardless of direction. Assuming the Copernican principle (that the Earth is not the center of the Universe), the only remaining interpretation is that all observable regions of the Universe are receding from all others. Since we know that the distance between galaxies increases today, it must mean that in   the past galaxies were closer together. The continuous expansion of the Universe implies that the Universe was denser and hotter in the past.



The Universe
The Universe

Friends, as you know that large particle accelerators can replicate the conditions that prevailed after the early moments of the Universe, resulting in confirmation and refinement of the details of the Big Bang model. However, these accelerators can only probe so far into high energy regimes. Consequently,   the state of the Universe in the earliest instants of the Big Bang expansion is still poorly understood and an area of open investigation and speculation.

The first subatomic particles to be formed included protons, neutrons, and electrons. Though simple atomic nuclei formed within the first three minutes after the Big Bang, thousands of years passed before the first electrically neutral atoms formed. The majority of atoms produced by the Big Bang were hydrogen, along with helium and traces of lithium. Giant clouds of these primordial elements later coalesced through gravity to form Stars and galaxies, and the heavier elements were synthesized either within Stars or during supernovae.


The Universe
The Universe

Guys, the American astronomer Edwin Hubble observed that the distances to faraway galaxies were strongly correlated with their redshifts. This was interpreted to mean that all distant galaxies and clusters are receding away from our vantage point with an apparent velocity proportional to their distance: that is, the farther they are, the faster they move away from us, regardless of direction. Assuming the Copernican principle (that the Earth is not the center of the Universe), the only remaining interpretation is that all observable regions of the Universe are receding from all others. Since we know that the distance between galaxies increases today, it must mean that in   the past galaxies were closer together. The continuous expansion of the Universe implies that the Universe was denser and hotter in the past. so the Big Bang theory offers a comprehensive explanation for a broad range of observed phenomena, including the abundance of light elements, the CMB, large Scale structure, and Hubble's Law. The framework for the Big Bang model relies on Albert Einstein's theory of general relativity and on simplifying assumptions such as homogeneity and isotropy of space. The governing equations were formulated by Alexander Friedman and similar solutions were worked on by Willem de Sitter. Since then, astrophysicists have incorporated observational and theoretical additions into the Big Bang model and its parametrization as the Lambda-CDM model serves as the framework for current investigations of theoretical cosmology. The Lambda-CDM model is the current "standard model" of Big Bang cosmology; consensus is that it is the simplest model that can account for the various measurements and observations relevant to cosmology.


The Universe - Master of the Universe  


Scale of Universe


The observable Universe is a spherical region of the Universe comprising all matter that can be observed from Earth or its space-based telescopes and exploratory probes at the present time, because electromagnetic radiation from these objects has had time to reach the Solar System and Earth since the beginning of the cosmological expansion. There are at least 2 trillion galaxies in the observable Universe. Assuming the Universe is isotropic, the distance to the edge of the observable Universe is roughly the same in every direction. That is, the observable Universe has a spherical volume (a ball) centered on the observer. Every location in the Universe has its own observable Universe, which may or may not overlap with the one centered on Earth.


The Universe
The Universe

The word observable in this sense does not refer to the capability of modern technology to detect light or other information from an object, or whether   there is anything to be detected. It refers to the physical limit Created by the speed of light itself. Because no signals can travel faster than light, any object farther away from us than light could travel in the age of the Universe (estimated as of 2015 around 13.799±0.021 billion years simply cannot be detected, as the signals could not have reached us yet. Sometimes astrophysicists distinguish between the visible Universe, which includes only signals emitted since recombination (when hydrogen atoms were formed from protons and electrons and Photons were emitted) and the observable Universe, which includes signals since the beginning of the cosmological expansion (the Big Bang in traditional physical cosmology, the end of the inflationary epoch in modern cosmology).


The Universe
The Universe

Friends, according to calculations, the current commoving distance-proper distance, which takes into account that the Universe has expanded since the light Was emitted-to particles from which the cosmic microwave background radiation (CMBR) Was emitted, which represents the radius of the visible Universe, is about 14.0 billion parsecs (about 45.7 billion light-years), while the commoving distance to the edge of the observable Universe is about 14.3 billion parsecs (about 46.6 billion light-years), about 2% larger. The radius of the observable Universe is therefore estimated to be about 46.5 billion light-years and its diameter about 28.5 gig parsecs (93 billion light-years, 8.8×1026 meters or 2.89×1027 feet). The total mass of ordinary matter in the Universe can be calculated using the critical density and the diameter of the observable Universe to be about 1.5 × 1053 kg. In November 2018, astronomers reported that the extragalactic background light (EBL) amounted to 4 × 1084 Photons.


The Universe
The Universe

As the Universe's expansion is accelerating, all currently observable objects will eventually appear to freeze in time, while emitting progressively redder and fainter light. For instance, objects with the current redshift z from 5 to 10 will remain observable for no more than 4–6 billion years. In addition, light emitted by objects currently situated beyond a certain commoving distance (currently about 19 billion parsecs) will never reach Earth.



The Universe versus the observable Universe


Some parts of the Universe are too far away for the light emitted since the Big Bang to have had enough time to reach Earth or its scientific space-based instruments and so lie outside the observable Universe. In the future, light from distant galaxies will have had more time to travel, so additional regions will become observable. However, due to Hubble's law, regions sufficiently distant from the Earth are Expanding away from it faster than the speed of light (special relativity prevents nearby objects in the same local region from moving faster than the speed of light with respect to each other, but there is no such constraint for distant objects when the space between them is Expanding; see uses of the proper distance for a discussion) and furthermore   the expansion rate appears to be accelerating due to dark energy. Assuming dark energy remains constant (an unchanging cosmological constant), so that   the expansion rate of the Universe continues to accelerate, there is a "future visibility limit" beyond which objects will never enter our observable Universe at any time in the Infinite future, because light emitted by objects outside that limit would never reach the Earth. (A subtlety is that, because   the Hubble parameter is decreasing with time, there can be cases where a galaxy that is receding from the Earth just a bit faster than light does emit a signal that reaches the Earth eventually. This future visibility limit is calculated at a commoving distance of 19 billion parsecs (62 billion light-years), assuming the Universe will keep Expanding forever, which implies   the number of galaxies that we can ever theoretically observe in the Infinite future (leaving aside the issue that some may be impossible to observe in practice due to redshift, as discussed in the following paragraph) is only larger than the number currently observable by a factor of 2.36.


The Universe
The Universe

Guys, although in principle more galaxies will become observable in the future, in practice an increasing number of galaxies will become extremely redshifted due to ongoing expansion, so much so that they will seem to disappear from view and become invisible. An additional subtlety is that a galaxy at a given commoving distance is defined to lie within the "observable Universe" if we can receive signals emitted by the galaxy at any age in its past history (say, a signal sent from the galaxy only 500 million years after the Big Bang), but because of the Universe's expansion, there may be some later age at which a signal sent from the same galaxy can never reach the Earth at any point in the Infinite future (so, for example, we might never see what the galaxy looked like 10 billion years after the Big Bang), even though it remains at the same commoving distance (commoving distance is defined to be constant with time-unlike proper distance, which is used to define recession velocity due to the expansion of space), which is less than the  commoving radius of   the observable Universe. This fact can be used to define a type of cosmic event horizon whose distance from the Earth changes over time. For example, the current distance to this horizon is about 16 billion light-years, meaning that a signal from an event happening at present can eventually reach the Earth in the future if the event is less than 16 billion light-years away, but the signal will never reach the Earth if the event is more than 16 billion light-years away.


The Universe
The Universe

friends, Now both popular and professional research articles in cosmology often use the term "Universe" to mean "observable Universe". This can be justified on the grounds that we can never know anything by direct experimentation about any part of the Universe that is causally disconnected from the Earth, although many credible theories require a total Universe much larger than the observable Universe. No evidence exists to suggest that the boundary of the observable Universe constitutes a boundary on the Universe as a whole, nor do any of the mainstream cosmological models propose that the Universe has any physical boundary in the first place, though some models propose it could be finite but unbounded, like a higher-dimensional analogue of   the 2D surface of a sphere that is finite in area but has no edge. It is plausible that the galaxies within our observable Universe represent only a minuscule fraction of   the galaxies in the Universe. According to the theory of cosmic inflation initially introduced by its founder, Alan Guth (and by D. Kazan as, if it is assumed that inflation began about 10−37 seconds after the Big Bang, then with the plausible assumption that the Size of the Universe before the inflation occurred was approximately equal to the speed of light times its age, that would suggest that at present the entire Universe's Size is at least 3×1023 times the radius of the observable Universe. There are also lower estimates claiming that the entire Universe is in excess of 250 times larger (by volume, not by radius) than the observable Universe and also higher estimates implying that the Universe could have the Size of at least 101010122 Mpc.


The Universe
The Universe

If the Universe is finite but unbounded, it is also possible that the Universe is smaller than the observable Universe. In this case, what we take to be very distant galaxies may actually be duplicate Images of nearby galaxies, formed by light that has circumnavigated the Universe. It is difficult to test this hypo thesis experimentally because different Images of a galaxy would show different eras in its history, and consequently might appear quite different. Bielewiczetal claim to establish a lower bound of 27.9 gig parsecs (91 billion light-years) on the diameter of the last scattering surface (since this is only a lower bound, the paper leaves open the possibility that the whole Universe is much larger, even Infinite). This value is based on matching-circle analysis of   the WMAP 7 year data.





Spread around


The commoving distance from Earth to the edge of the observable Universe is about 14.26 gig parsecs (46.5 billion light-years or 4.40×1026 meters) in any direction. The observable Universe is thus a sphere with a diameter of about 28.5 gig aparsecs (93 billion light-years or 8.8×1026 meters). Assuming that space is roughly flat (in the sense of being a Euclidean space), this Size corresponds to a commoving volume of about 1.22×104 Gpc3 (4.22×105 Gly3 or 3.57×1080 m3).

These figures quoted above are distances now (in cosmological time), not distances at the time the light was emitted. For example, the cosmic microwave background radiation that we see right now was emitted at the time of Photon decoupling, estimated to have occurred about 380,000 years after the Big Bang which occurred around 13.8 billion years ago. This radiation was emitted by matter that has, in the intervening time, mostly condensed into galaxies, and those galaxies are now calculated to be about 46 billion light-years from us. 


The Universe
The Universe

To estimate the distance to that matter at the time the light was emitted, we may first note that according to the Friedman–Lemaitre–Robertson–Walker metric, which is used to model the Expanding Universe, if at the present time we receive light with a redshift of z, then the Scale factor at the time the light was originally emitted is given by WMAP nine-year results combined with other measurements give the redshift of Photon decoupling as z = 1091.64±0.47, which implies that the Scale factor at   the time of Photon decoupling would be 1⁄1092.64. So if the matter that originally emitted the oldest CMBR Photons has a present distance of 46 billion light-years, then at the time of decoupling when the Photons were originally emitted, the distance would have been only about 42 million light-years.

Here is an example of the misconception that the radius of the observable Universe is 13 billion light-years. This plaque appears at the Rose Center for Earth and Space in New York City.

Many secondary sources have reported a wide variety of incorrect figures for   the Size of the visible Universe. Some of these figures are listed below, with brief descriptions of possible reasons for misconceptions about them.

1- Billion Light-Years old


The age of the Universe is estimated to be 13.8 billion years. While it is commonly understood that nothing can accelerate to velocities equal to or greater than that of light, it is a common misconception that the radius of the observable Universe must therefore amount to only 13.8 billion light-years. This reasoning would only make sense if the flat, static Murkowski space-time conception under special relativity were correct. In the real Universe, space-time is curved in a way that corresponds to the expansion of space, as evidenced by Hubble's law. Distances obtained as the speed of light multiplied by a cosmological time interval have no direct physical significance.

2- Billion Light-Years old


This is obtained in the same way as the 13.8-billion-light-year figure, but Starting from an incorrect age of the Universe that the popular press reported in mid-2006. For an analysis of this claim and the paper that prompted it, see   the following reference at the end of this article.

3- Billion Light-Years old


This is a diameter obtained from the (incorrect) radius of 13.8 billion light-years.

4- 78 Billion Light-Years old


In 2003, Corniche Al. found this lower bound for the diameter of the whole Universe (not just the observable part), postulating that the Universe is finite in Size due to it having a nontrivial topology with this lower bound based on   the estimated current distance between points that we can see on opposite sides of the cosmic microwave background radiation (CMBR). If the whole Universe is smaller than this sphere, then light has had time to circumnavigate it since the Big Bang, producing multiple Images of distant points in the CMBR, which would show up as patterns of repeating circles. Cornish et al. looked for such an effect at Scales of up to 24 gig aparsecs (78 Gly or 7.4×1026 m) and failed to find it, and suggested that if they could extend their search to all possible orientations, they would then "be able to exclude the possibility that we live in a Universe smaller than 24 Gpc in diameter". The authors also estimated that with "lower noise and higher resolution CMB Maps (from WMAP's extended mission and from Planck), we will be able to search for smaller circles and extend the limit to ~28 Gpc." This estimate of the maximum lower bound that can be established by future observations corresponds to a radius of 14 gig parsecs, or around 46 billion light-years, about the same as the figure for the radius of the visible Universe (whose radius is defined by the CMBR sphere) given in the opening section. A 2012 preprint by most of the same authors as the corniches Al. paper has extended   the current lower bound to a diameter of 98.5% the diameter of the CMBR sphere, or about 26 Gpc.

5- 156 Billion Light-Years old


This figure was obtained by doubling 78 billion light-years on the assumption that it is a radius. Because 78 billion light-years is already a diameter (the original paper by Cornish et al. says, "By extending the search to all possible orientations, we will be able to exclude the possibility that we live in a Universe smaller than 24 Gpc in diameter," and 24 Gpc is 78 billion light-years) the doubled figure is incorrect. This figure was very widely reported. A press release from Montana State University–Bozeman, where Cornish works as an astrophysicist, noted the error when discussing a story that had appeared in Discover magazine, saying "Discover mistakenly reported that the Universe Was 156 billion light-years wide, thinking that 78 billion was the radius of the Universe instead of its diameter. “As noted above, 78 billion was also incorrect.

6- 180 Billion Light-Years old


This estimate combines the erroneous 156-billion-light-year figure with evidence that the M33 Galaxy is actually fifteen percent farther away than previous estimates and that, therefore, the Hubble constant is fifteen percent smaller. The 180-billion figures are obtained by adding 15% to 156 billion light-years.


The Universe
The Universe


Large-Scale Structure


The Sky surveys and Mappings of the various wavelength bands of electromagnetic radiation (in particular 21-cm emission) have yielded much information on the content and character of the Universe's structure. The organization of structure appears to follow as a hierarchical model with organization up to the Scale of superclusters and filaments. Larger than this (at Scales between 30 and 200 mega parsecs, there seems to be no continued structure, a phenomenon that has been referred to as the End of Greatness.

Walls, Filaments, Nodes and Voids


The organization of structure arguably begins at the stellar level, though most cosmologists rarely address astrophysics on that Scale. Stars are organized into galaxies, which in turn form galaxy groups, galaxy clusters, superclusters, sheets, walls and filaments, which are separated by immense voids, creating a vast foam-like structure sometimes called the "cosmic web". Prior to 1989, it was commonly assumed that virialized galaxy clusters were the largest structures in existence, and that they were distributed more or less uniformly throughout the Universe in every direction. However, since the early 1980s, more and more structures have been discovered. In 1983, Adrian Webster identified the Webster LQG, a large quasar group consisting of 5 quasars. The discovery was the first identification of a large-Scale structure and has expanded the information about the known grouping of matter in the Universe. In 1987, Robert Brent Tully identified the Pisces–Cetus Supercluster Complex, the galaxy filament in which the Milky Way resides. It is about 1 billion light-years across. That same year, an unusually large region with a much lower than average distribution of galaxies was discovered, the Giant Void, which measures 1.3 billion light-years across. Based on redshift survey data, in 1989 Margaret Geller and John Huchra discovered the "Great Wall", a sheet of galaxies more than 500 million light-years long and 200 million light-years wide, but only 15 million light-years thick. 


The Universe
The Universe

The existence of this structure escaped notice for so long because it requires locating the position of galaxies in three dimensions, which involves combining location information about the galaxies with distance information from redshifts. Two years later, astronomers Roger G. Clowes and Luis E. Campusano discovered   the Clowes–Campusano LQG, a large quasar group measuring two billion light-years at its widest point which was the largest known structure in the Universe at the time of its announcement. In April 2003, another large-Scale structure was discovered, the Sloan Great Wall. In August 2007, a possible super void was detected in the constellation Eridanus. It coincides with   the 'CMB cold spot', a cold region in the microwave sky that is highly improbable under the currently favored cosmological model. This super void could cause   the cold spot, but to do so it would have to be improbably big, possibly a billion light-years across, almost as big as the Giant Void mentioned above.

Another large-Scale structure is the SSA22 Proto cluster, a collection of galaxies and enormous gas bubbles that measures about 200 million light-years across.


The Universe
The Universe

In 2011, a large quasar group was discovered, U1.11, measuring about 2.5 billion light-years across. On January 11, 2013, another large quasar group,   the Huge-LQG, was discovered, which was measured to be four billion light-years across, the largest known structure in the Universe at that time. In November 2013, astronomers discovered the Hercules–Corona Borealis Great Wall, an even bigger structure twice as large as the former. It was defined by   the Mapping of gamma-ray bursts.

End of the Greatness


Thus the End of Greatness is an observational Scale discovered at roughly 100 Mpc (roughly 300 million light-years) where the lumpiness seen in the large-Scale structure of the Universe is homogenized and isotropies in accordance with the Cosmological Principle. At this Scale, no pseudo-random fractalness is apparent. The superclusters and filaments seen in smaller surveys are randomized to the extent that the smooth distribution of the Universe is visually apparent. It was not until the redshift surveys of the 1990s were completed that this Scale could accurately be observed.


The Universe
The Universe


An Experience-Practical Challenge


Another indicator of large-Scale structure is the 'Lyman-alpha forest'. This is a collection of absorption lines that appear in the spectra of light from quasars, which are interpreted as indicating   the existence of huge thin sheets of intergalactic (mostly hydrogen) gas. These sheets appear to be associated with the formation of new galaxies.

Caution is required in describing structures on a cosmic Scale because things are often different from how they appear. Gravitational lensing (bending of light by gravitation) can make an image appear to originate in a different direction from its real source. This is caused when foreground objects (such as galaxies) curve surrounding space-time (as predicted by general relativity), and deflect passing light rays. Rather usefully, strong gravitational lensing can sometimes magnify distant galaxies, making them easier to detect. Weak lensing (gravitational shear) by the intervening Universe in general also subtly changes the observed large-Scale structure.


The Universe
The Universe

The large-Scale structure of the Universe also looks different if one only uses redshift to measure distances to galaxies. For example, galaxies behind a galaxy cluster are attracted to it, and so fall towards it, and so are slightly blue shifted (compared to How   they would be if there were no cluster) on the near side, things are slightly redshifted. Thus, the environment of the cluster looks a bit squashed if using redshifts to measure distance.

An opposite effect works on the galaxies already within a cluster


The galaxies have some random motion around the cluster center, and when these random motions are converted to redshifts, the cluster appears elongated. This creates a "Finger of God"- the illusion of a long chain of galaxies pointed at the Earth.

The Cosmography of Earth's cosmic neighborhood


At the center of the Hydra-Centaurus Supercluster, a gravitational anomaly called the Great Attractor affects the motion of galaxies over a region hundreds of millions of light-years across. These galaxies are all redshifted, in accordance with Hubble's law. This indicates that they are receding from us and from each other, but the variations in their redshift are sufficient to reveal the existence of a concentration of mass equivalent to tens of thousands of galaxies.


The Universe
The Universe

The Great Attractor, discovered in 1986, lies at a distance of between 150 million and 250 million light-years (250 million is the most recent estimate), in   the direction of the Hydra and Centaurus constellations. In its vicinity   there is a preponderance of large old galaxies, many of which are colliding with their neighbors, or radiating large amounts of radio waves.

In 1987, astronomer R. Brent Tully of the University of Hawaii's Institute of Astronomy identified what he called the Pisces–Cetus Supercluster Complex, a structure one billion light-years long and 150 million light-years across in which, he claimed, the Local Supercluster was embedded.

The Mass of ordinary Matter


The mass of the observable Universe is often quoted as 1050 tones or 1053 kgs. In this context, mass refers to ordinary matter and includes the interstellar medium (ISM) and the intergalactic medium (IGM). However, it excludes dark matter and dark energy. This quoted value for the mass of ordinary matter in the Universe can be estimated based on critical density.   The calculations are for the observable Universe only as the volume of the whole is unknown and may be Infinite.

The Estimates based on critical density


Critical density is the energy density for which the Universe is flat. If   there is no dark energy, it is also the density for which the expansion of the Universe is poised between continued expansion and collapse. From the Friedman equations, the value for critical density is where G is the gravitational constant and H = H0 is the present value of the Hubble constant. The value for H0, due to the European Space Agency's Planck Telescope, is H0 = 67.15 kilometers per second per mega parsec. This gives a critical density of 0.85×10−26 kg/m3 (commonly quoted as about 5 hydrogen atoms per cubic meter). This density includes four significant types of energy/mass- ordinary matter (4.8%), neutrinos (0.1%), cold dark matter (26.8%) and dark energy (68.3%).


The Universe
The Universe

Although neutrinos are Standard Model particles, they are listed separately because they are ultra-relativistic and hence behave like radiation rather than like matter. The density of ordinary matter, as measured by Planck, is 4.8% of   the total critical density or 4.08×10−28 kg/m3. To convert this density to mass we must multiply by volume, a value based on the radius of the "observable Universe". Since the Universe has been Expanding for 13.8 billion years, the commoving distance (radius) is now about 46.6 billion light-years. Thus, volume (4/3πr3) equals 3.58×1080 m3 and the mass of ordinary matter equals density (4.08×10−28 kg/m3) time’s volume (3.58×1080 m3) or 1.46×1053 kg.

The Matter content–number of Atoms


Assuming the mass of ordinary matter is about 1.45×1053 kg and assuming all atoms are hydrogen atoms (which are about 74% of all atoms in our galaxy by mass, see Abundance of the chemical elements), calculating the estimated total number of atoms in the observable Universe is straightforward. Divide   the mass of ordinary matter by the mass of a hydrogen atom (1.45×1053 kg divided by 1.67×10−27 kg). The result is approximately 1080 hydrogen atoms.

The Most distant Objects


The most distant astronomical object yet announced as of 2016 is a galaxy classified GN-z11. In 2009, a gamma ray burst, GRB 090423, was found to have a redshift of 8.2, which indicates that the collapsing Star that caused it exploded when the Universe was only 630 million years old. The burst happened approximately 13 billion years ago so a distance of about 13 billion light-years was widely quoted in the media (or sometimes a more precise figure of 13.035 billion light-years), though this would be the "light travel distance" (see Distance measures (cosmology)) rather than the "proper distance" used in both Hubble's law and in defining the Size of the observable Universe (cosmologist Ned Wright argues against the common use of light travel distance in astronomical press releases on this page, and at the bottom of the page offers online calculators that can be used to calculate the current proper distance to a distant object in a flat Universe based on either the redshift z or the light travel time). 


The Universe
The Universe

The proper distance for a redshift of 8.2 would be about 9.2 Gpc or about 30 billion light-years. Another record-holder for most distant object is a galaxy observed through and located beyond Abell 2218, also with a light travel distance of approximately 13 billion light-years from Earth, with observations from the Hubble telescope indicating a redshift between 6.6 and 7.1, and observations from Keck telescopes indicating a redshift towards the upper end of this range, around 7. The galaxy's light now observable on Earth would have begun to emanate from its source about 750 million years after the Big Bang.

The Horizons


This limit of observability in our Universe is set by a set of cosmological horizons which limit-based on various physical constraints-the extent to which we can obtain information about various events in the Universe. The most famous horizon is the particle horizon which sets a limit on the precise distance that can be seen due to the finite age of the Universe. Additional horizons are associated with the possible future extent of observations (larger than the particle horizon owing to the expansion of space), an "optical horizon" at the surface of last scattering, and associated horizons with the surface of last scattering for neutrinos and gravitational waves. 



The Universe Scale, the Universe Map



The Universe in a Nutshell


The Universe in a Nutshell is a 2001 Book about theoretical physics by Stephen Hawking. It is generally considered a sequel and Was Created to update the public concerning developments since the multi-million-copy bestseller A Brief History of Time published in 1988. 


What is Universe Answer? 


In it Hawking explains to a general audience various matters relating to the Lucasian professor's work, such as Gödel's Incompleteness theorem and P-branes (part of superstring theory in quantum mechanics). He tells the history and principles of modern physics. He seeks to "combine Einstein's General theory of Relativity and Richard Feynman's idea of multiple histories into one complete unified theory that will describe everything that happens in the Universe.

The Universe Book


John Brockman brings together the world's best-known physicists and science writers-including Brian Greene, Walter Isaacson, Nobel Prize-winner Frank Wilczek, Benoit Mandelbrot, and Martin Rees-to explain the Universe in all wondrous splendors. 

In the Universe, today's most influential science writers explain the science behind our evolving understanding of the Universe and everything in it, including the cutting edge research and discoveries that are shaping our knowledge. 


The Universe
The Universe

Lee Smolin reveals how math and cosmology are helping us create a theory of the whole Universe. Benoit Mandelbrot looks back on a career devoted to fractal geometry. Neil Turok analyzes the fundamental laws of nature, what came before the big bang and the possibility of a unified theory. 

Seth Lloyd investigates the impact of computational revolutions and the informational revolution. Lawrence Krauss provides fresh insight into gravity, dark matter and the energy of empty space. Brian Greene and Walter Isaacson illuminate the genius who revolutionized modern science: Albert Einstein.


  •    Explore the Universe with some of today's greatest minds
  •    What it is, how it came into being and what may happen next?  


The Universe Usage


The Universe (singular) the whole of space and everything in it, including the earth, the Planets and the Stars.

The Universe Humanity


Humanity may be alone in the Universe - there may never have been another intelligent, technologically advanced alien species in the entire history of the Universe. Last week, in the New York Times, scientist Adam Frank emphatically wrote that Yes, there Have Been Aliens, concluding that given all the potentially habitable worlds we know must be out there from our astrophysical discoveries, intelligent life must have arisen. What he fails to account for however is the magnitude of the unknowns that abiogenesis, evolution, long-term habitability and other factors bring into the equation. Although it's true that there are an astronomical number of possibilities for intelligent, technologically advanced lifeforms, the huge uncertainties make it a very real possibility that humans are the only spacefaring aliens our Universe has ever known. 


The Universe
The Universe

Back in 1961, Scientist Frank Drake came up with the first equation to predict how many spacefaring civilizations there were in the Universe today. He relied on a series of unknown quantities that he could make estimates for, and ultimately arrive at how many technologically advanced alien species there were, at present, in both our galaxy and our observable Universe right now. With the advances of the last 55 years, many of those quantities we once could only estimate via guesswork can now be known to an incredible degree of precision. 


The Universe
The Universe

For Starters, our understanding of the Size and Scale of the Universe has increased dramatically. We now know, thanks to observations made with space-based and ground-based observatories covering the full spectrum of the electromagnetic wavelengths, how big the Universe is and how many galaxies there are within it. We have a much better understanding of Star formation and How Stars work, and so when we look out into the grand abyss of deep space, we can calculate how many Stars there are out there in the Universe, both now and over the entire cosmic history since the Big Bang. That number is huge -- somewhere close to 10^24 -- and it represents the number of chances the Universe has had, over the past 13.  8 billion years, to produce life like ours. 

We used to wonder How many of those Stars had Planets around them, How many of those Planets were rocky and capable of having atmospheres like our own, and How many of them were the right distances from their Stars to have liquid water on their surfaces. For innumerable generations, this was something we only wondered about. But thanks to huge advances in exoplanet studies, most spectacularly with the advent of NASA's Kepler spacecraft, we've learned so much about what's out there, including that:

Somewhere between 80-100% of Stars have Planets or planetary System orbiting them,

Approximately 20-25% of those Systems have a planet in their Star's "habitable zone," or the right location for liquid water to form on their surface,

And approximately 10-20% of those Planets are Earth-like in Size and mass.



So adding that all up, there are more than 10^22 potentially Earth-like Planets out there in the Universe with the right conditions for life on them.
 

The Universe
The Universe

The situation is even better than that, because except for the very first generations of the very first Stars, practically all of them come enriched with the heavy elements and ingredients necessary for life. When we look at the interstellar medium, at molecular gas clouds, at the centers of distant galaxies, at outflows from massive Stars or even at our own galaxy, we find the elements of the periodic table -- carbon, nitrogen, oxygen, silicon, Sulphur, phosphorous, copper, iron and more -- necessary for life as we know it. When we look inside meteors and asteroids in our own Solar System, we find not only these elements, but we find them configured into organic molecules like sugars, carbon rings and even amino acids. In other words, there are not only more than 10^22 potentially Earth-like Planets out there in the Universe; there are more than 10^22 potentially Earth-like Planets with the right raw ingredients for life!


The Universe
The Universe

But that's where our optimism, if we're being scientifically honest and scrupulous, ought to end. Because there are three big steps out there, in order to get a human-like civilization, that needs to happen:

1. The step of abiogenesis - where the raw ingredients associated with organic processes actually become what we recognize as "life" -- needs to occur. 

2. Life must survive and thrive for billions of years on a planet in order to evolve multicellularity, complexity, differentiation and what we call "intelligence".

3. And finally, that intelligent life must then become a technological civilization, either gaining the ability to announce its presence to the Universe, to reach out beyond its home and explore the Universe, or to reach the stage where it can listen for other forms of intelligence in the Universe Or, more optimistically, all three. 

When Carl Sagan originally presented Cosmos in 1980, he claimed it was reasonable to give each of these three steps a 10% chance of succeeding. If that were correct, there would be more than 10 million intelligent, alien civilizations that have existed in the Milky Way galaxy alone!


The Universe
The Universe

Today, Adam Frank argues that it's unrealistic to give these three steps a combined probability of less than 10^-22, and therefore concludes that there must have been aliens elsewhere in the Universe. But this is itself a preposterous claim, based on no evidence whatsoever. Abiogenesis may have been common; it may have occurred multiple times on Earth alone, or on Mars, Titan, Europa, Venus, Enceladus, or elsewhere even in our own Solar System. Or it may be such a rare process that even if we created a hundred clones of a young Earth -- or a thousand, or a million -- our world might be the only one where it occurred. 






And even if life does occur, how fortunate do you need to be to have it survive and thrive for billions of years? Would a catastrophic warming scenario, like Venus, be the norm? Or a catastrophic freezing scenario, like on Mars? Or would life wind up poisoning itself out of existence most of the time, as it almost did on Earth two billion years ago? And even if you had life make it for billions of years, how often would you get something like the Cambrian explosion, where huge, multicellular, macroscopic plants, animals and fungi came to dominate a planet? It could be relatively common, where maybe 10% of attempts make it, or it could be rare, where 1-in-a-million or even 1-in-a-billion are closer to the realistic odds. 


The Universe
The Universe

And even if you get there, how rare is a tool-using, technology-developing, rocket ship-launching species like a human? Complex reptiles, birds and mammals that could be considered intelligent by many metrics have been around for tens to hundreds of millions of years, but modern humans came about less than one million years ago, and we only became what we'd consider "technologically advanced" in the last century or two. Is there a 10% chance that if you make it through the previous step, you get to a spacefaring civilization? Or is that more like one-in-a-thousand, one-in-a-million, one-in-a-trillion or even worse?

The truth of the Matter


We don't know. We know the Universe gives intelligent life a very large number of chances on the order of 10^22. And we know that there's only a small probability of going from a chance at life to a spacefaring, technologically advanced civilization. What we don't know is whether that chance is something like 10^-3, 10^-20, 10^-50, or any number in between (or even worse). We know that life like humans arose once, at least, so the probability must be non-zero. But beyond that? We need data. And no amount of speculation or pronouncements will substitute for that information; we've got to find it to know. Anything else, despite what the New York Times claims is nothing more than guesswork. 


The Universe Earth


The knowledge of the location of Earth has been shaped by 400 years of telescopic observations and has expanded radically since the start of the 20th century. Initially, Earth was believed to be the center of the Universe, which consisted only of those Planets visible with the naked eye and an outlying sphere of fixed Stars. After the acceptance of the heliocentric model in the 17th century, observations by William Herschel and others showed that the Sun lay within a vast, disc-shaped galaxy of Stars. By the 20th century, observations of spiral nebulae revealed that the Milky Way galaxy was one of billions in an Expanding Universe grouped into clusters and superclusters. By the end of the 20th century, the overall structure of the visible Universe was becoming clearer, with superclusters forming into a vast web of filaments and voids. Superclusters, filaments and voids are the largest coherent structures in the Universe that we can observe. At still larger Scales (over 1000 mega parsecs) the Universe becomes homogeneous, meaning that all its parts have on average the same density, composition and structure.
 

The Universe
The Universe

Since there is believed to be no "center" or "edge" of the Universe, there is no particular reference point with which to plot the overall location of the Earth in the Universe. Because the observable Universe is defined as that region of the Universe visible to terrestrial observers, Earth is, because of the constancy of the speed of light, the center of Earth's observable Universe. Reference can be made to the Earth's position with respect to specific structures, which exist at various Scales. It is still undetermined whether the Universe is Infinite. There have been numerous hypotheses that the known Universe may be only one such example within a higher multiverse; However, no direct evidence of any sort of multiverse has been observed and some have argued that the hypothesis is not falsifiable. 

Description


The Earth is the third planet from the Sun with an approximate distance of 149.6 million kilometers (93.0 million miles) and is traveling nearly 1.6 million kilometers per hour (1 million miles per hour) through outer space.


Earth (Diameter) 12,756.2 km (equatorial)

Measurement comprises just the solid part of the Earth; there is no agreed upper boundary for Earth's atmosphere. The Geocorona, a layer of UV-luminescent hydrogen atoms, lies at 100,000 km. the Kármán line, defined as the boundary of space for astronautics, lies at 100 km.

 

Orbit of the Moon (Diameter) 768,210 km

The average diameter of the orbit of the Moon relative to the Earth.

 

Geospace (Diameter) 6,363,000–12,663,000 km (110–210 Earth radii)

The space dominated by Earth's magnetic field and its magneto tail, shaped by the Solar wind.

 

Earth's orbit (Diameter) 299.2 million km 2 AU

The average diameter of the orbit of the Earth relative to the Sun. Encompasses the Sun, Mercury and Venus.

 

Inner Solar System (Diameter) ~6.54 AU

Encompasses the Sun, the inner Planets (Mercury, Venus, Earth, and Mars) and the asteroid belt. Cited distance is the 2:1 resonance with Jupiter, which marks the outer limit of the asteroid belt.

 

Outer Solar System (Diameter) 60.14 AU

Includes the outer Planets (Jupiter, Saturn, Uranus and Neptune). Cited distance is the orbital diameter of Neptune.

 

Kuiper Belt (Diameter) ~96 AU

Belt of icy objects surrounding the outer Solar System. Encompasses the dwarf Planets Pluto, Haumea and Make. Cited distance is the 2:1 resonance with Neptune, generally regarded as the inner edge of the main Kuiper belt.

 

Heliosphere (Diameter) 160 AU

Maximum extent of the Solar wind and the Interplanetary Medium.

 

Scattered Disc (Diameter) 195.3 AU

Region of sparsely scattered icy objects surrounding the Kuiper belt. Encompasses the dwarf planet Eris. Cited distance is derived by doubling the Aphelion of Eris, the farthest known scattered disc object. As of now, Eris's aphelion marks the farthest known point in the scattered disc.

 

Oort Cloud (Diameter) 100,000–200,000 AU 0.613–1.23 pc

Spherical shell of over a trillion (1012) comets. Existence is currently hypothetical, but inferred from the orbits of long-period comets.

 

Solar System (Diameter) 1.23 pc

The Sun and its planetary System. Cited diameter is that of the Sun's Hill sphere; the region of its gravitational influence.

 

Local Interstellar Cloud (Diameter) 9.2 pc

Interstellar cloud of gas through which the Sun and a number of other Stars are currently travelling.

 

Local Bubble (Diameter) 2.82–250 pc

Cavity in the interstellar medium in which the Sun and a number of other Stars are currently travelling. Caused by a past supernova.

 

Gould Belt (Diameter) 1,000 pc

Ring of young Stars through which the Sun is currently travelling.

 

Orion Arm (Diameter) 3000 pc (length)

The Spiral Arm of the Milky Way Galaxy through which the Sun is currently travelling.

 

Orbit of   the Solar System (Diameter) 17,200 pc

The average diameter of the orbit of the Solar System relative to the Galactic Center. The Sun's orbital radius is roughly 8,600 parsecs, or slightly over half way to   the galactic edge. One orbital period of the Solar System lasts between 225 and 250 million years.

 

Milky Way Galaxy (Diameter) 30,000 pc

Our home Galaxy composed of 200 billion to 400 billion Stars and filled with the Interstellar Medium.

 

Milky Way Subgroup (Diameter) 840,500 pc

The Milky Way and those satellite dwarf galaxies gravitationally bound to it. Examples include the Sagittarius Dwarf, the Ursa Minor Dwarf and the Canis Major Dwarf. Cited distance is the orbital diameter of the Leo T Dwarf galaxy, the most distant galaxy in the Milky Way subgroup.

 

Local Group (Diameter) 3 Mpc

Group of at least 54 galaxies of which the Milky Way is a part. Dominated by Andromeda (the largest), the Milky Way and Triangulum; the remainder are dwarf galaxies.

 

Local Sheet (Diameter) 7 Mpc

Group of galaxies including the Local Group moving at the same relative velocity towards the Virgo Cluster and away from the Local Void.

 

Virgo Supercluster (Diameter) 30 Mpc

The supercluster of which the Local Group is a part. It comprises roughly 100 galaxy groups and clusters, centered on the Virgo Cluster. The Local Group is located on the outer edge of the Virgo Supercluster.

 

Laniakea (Diameter) 160 Mpc

A group connected with superclusters of which the Local Group is a part. Comprises roughly 300 to 500 Galaxy groups and clusters, centered on the Great Attractor in the Hydra-Centaurus Supercluster.

 

Observable Universe (Diameter) 28,500 Mpc

At least 2 trillion galaxies in the observable Universe, arranged in millions of superclusters, galactic filaments & voids, creating a foam-like superstructure.

 

Universe (Diameter) Minimum 28,500 Mpc possibly Infinite

Beyond the observable Universe lie the unobservable regions from which no light has reached the Earth yet. No information is available, as light is the fastest travelling medium of information. However, uniformitarianism argues that Universe is likely to contain more galaxies in the same foam-like superstructure.



Pictures of the Universe



Spectacular NASA images of interesting scenes in the Universe


A collection of images representing some of the most impressive views in our universe. Included are the Orion Nebula, a dying star, spiral galaxy, birth of a star, the Eagle Nebula, extrasolar planet, a galaxy pair and the Cartwheel Galaxy. Many of these are false-color images, enhanced to yield an artistic view.



 

THE UNIVERSE AND BEYOND



Spiral Galaxy


The magnificent M81 spiral galaxy takes center stage in this ultraviolet image from NASA's Galaxy Evolution Explorer. Young stars appear as wisps of bluish-white swirling around a central golden glow, which comes from a group of much older stars.


The large fluffy bluish-white material to the left of M81 is a neighboring galaxy called Homberg IX. This galaxy is practically invisible to the naked human eye. However, when viewed in ultraviolet light, a region that is actively forming young stars is revealed. Image and caption by NASA.

 

WHAT IS BEYOND THE UNIVERSE?


 

Stellar Babies

 

Infant stars are glowing gloriously in this infrared image of the Serpens star-forming region, located approximately 848 light-years away in the Serpens constellation.

The reddish-pink dots are baby stars deeply embedded in the cosmic cloud of gas and dust that collapsed to create the stars. Dusty disks of cosmic debris that may eventually form planets surround the infant stars. NASA's Spitzer Space Telescope took this image. Image and caption by NASA.

 

THE UNIVERSE


 

Chaos in Orion

Baby stars are creating chaos 1,500 light-years away in a cosmic cloud called the Orion nebula. Four massive stars make up the bright yellow area in the center of this false-color image from NASA's Spitzer and Hubble Space Telescopes.



Green indicates hydrogen and sulfur gas in the nebula, which is a cocoon of gas and dust. Red and orange are carbon-rich molecules. Infant stars appear as orange-yellow dots embedded in the nebula. Image and caption by NASA.

 

THE UNIVERSE AND BEYOND


 

Eagle Nebula

 

A star-making region famous for its space pillars appears in this infrared view from Spitzer. Green denotes cooler dust, including the pillars seen in the center. Red represents hotter dust thought to have been warmed by the explosion of a massive star about 8,000 to 9,000 years ago. 

 

Astronomers estimate that the explosion's blast wave would have spread outward and toppled the three pillars about 6,000 years ago. Since light from the Eagle nebula takes 7,000 years to reach us, this means we wouldn't witness the destruction for about 1,000 years. Image and caption by NASA.

 

 

WHAT IS BEYOND THE UNIVERSE?


 

Cartwheel Galaxy

 

A false-color view of the Cartwheel galaxy, created with data from Spitzer, Galaxy Evolution Explorer, Hubble and Chandra caption by NASA.

 

 

WHAT IS BEYOND THE UNIVERSE?


 

This image shows the "last hurrah" of a star like our sun. The star is ending its life by casting off its outer layer of gas, which formed a cocoon around the star's remaining core. Ultraviolet light from the dying star makes the material glow.


The burned-out star, called a white dwarf, is the white dot in the center. Our sun will eventually burn out and shroud itself with stellar debris, but not for another 5 billion years. NASA's Hubble Space Telescope captured this view. Image and caption by NASA.

 

 Galactic Pair




Galactic Pair

 

An interacting pair of galaxies, together called Arp 82, is a scientific oddball. The color in the "tilted S" pair indicate that the observed stars are young to intermediate in age, around 2 million to 2 billion years old, much less the age of the universe (13.7 billion years). Scientists wonder why Arp 82 didn't form many stars earlier, like most galaxies of its mass.

 

The Spitzer Space Telescope, the Galaxy Evolution Explorer and the Southeastern Assoc. for Research in Astronomy Observatory contributed to this image. Image and caption by NASA.

 

Alien World


 

 Alien World


This is the first-ever map of the surface of a planet beyond our solar system. The map, which shows temperature variations across the cloudy tops of a gas giant called HD 189733b, is made up of infrared data take by Spitzer. Hotter temperatures are represented in brighter colors.

 

The map tells astronomers that temperatures on HD 189733b are fairly even all around. While the dark side is about 650 degrees Celsius (about 1,200 degrees Fahrenheit), the sunlit side is just a bit hotter at 930 degrees Celsius (1,700 degrees Fahrenheit). Image and caption by NASA.

 

Kaleidoscope of Color


 

Kaleidoscope of Color

A giant jet of particles, shot out from the vicinity of a quasar, a type of supermassive black hole, takes center stage in this false-color image.

Quasars consist of supermassive black holes surrounded by turbulent material, which is being heated up as it is dragged toward the black hole. This hot material glows brilliantly, and some of it gets blown off into space in the form of powerful jets. NASA's Hubble, Chandra and Spitzer Space Telescopes contributed to this image. Image and caption by NASA.

 

 

FAQ

What is Beyond The Universe?

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What Is Beyond The Observable Universe?

If The Universe is infinite will I Live Again

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10 Sentences about Universe

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Our Universe Name

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