Everything about space From the Beginning to the End of Time

Do you know some interesting facts about our own universe? Explore the birth of the universe How the universe was born? When was time created?

It suddenly struck me that that tiny pea, pretty and blue, was the Earth. I put up my thumb and shut one eye, and my thumb blotted out the planet Earth. I didn’t feel like a giant. I felt very, very small. —Neil Armstrong 


This image, showing the inside surface of the heat shield of NASA’s Curiosity rover, was obtained during its descent to the surface of Mars on August 6, 2012. The Mars Descent Imager instrument, known as MARDI, shows the 15-foot (4.5- meter) heat shield at about 50 feet (16 meters) from the spacecraft

13.7 Billion BCE


There’s no better place to start considering the broad sweep of astronomical history than the beginning—that is, the actual beginning of both space and time. Twentieth-century cosmologists such as Edwin Hubble discovered that the universe is expanding by observing that large-scale structures like galaxies are all moving away from each other, in any direction that we look. This means that, in the past, the universe was smaller and that, at some point in the far distant past, everything started out as a single point of space and time: a singularity. Years of careful observations by the Hubble Space Telescope and other facilities have revealed that the universe was born in a violent explosion of this singularity about 13.7 billion years ago.


The details of big bang theory—as it was initially dubbed by astronomers in the 1930s—have been rigorously tested with decades of astronomical observations, laboratory experiments, and mathematical modeling by cosmologists and astronomers who specifically focus their research on the origin and evolution of the universe. What we have learned about the early history of our universe from these studies is impressive: within the first second of the universe’s existence, the temperature dropped from a million billion degrees to “only” 10 billion degrees, and all of the universe’s present supply of protons (hydrogen atoms) and neutrons formed out of this primordial plasma. By the time the universe was only three minutes old, helium and other light elements had been formed from hydrogen in the same kind of nuclear fusion process that still occurs today deep inside of stars.


It’s also humbling to realize that the most abundant element within each of our bodies—hydrogen—was created in the very first second that ever was. We are ancient!


It’s mind-blowing to think about both space and time being created at a single instant, 13.7 billion years ago. What caused the explosion? What was there before the big bang? Cosmologists tell us that we can’t really ask that question because time itself was created in the big bang.

How the universe was born?

Graphically portraying the start of the universe is similarly just about as trying as
attempting to get it! Here, a craftsman has whimsically caught the possibility that the enormous detonation was set off by a crash with another three-dimensional universe that had been covered up in higher measurements


The universe’s early years were a time of intense heat, pressure, and radiation. All of space was bathed in the primordial light of highly ionized atoms and subatomic particles, interacting, colliding, decaying, and recombining at temperatures of millions of degrees. This period in cosmic history is often referred to as the radiation era. By the time the universe was about 10,000 years old, the expansion of space and the decay of many energetic particles had cooled the cosmos to “only” about 12,000 kelvins (kelvins, or K, are a measure of the temperature above absolute zero). This was an important threshold, because as the universe continued to cool, the total energy from heat and ionizing radiation became less than the total so-called rest mass energy of matter itself, embodied in physicist Albert Einstein’s famous equation E = mc 2 . Still, for hundreds of thousands of years longer, the universe was essentially just an opaque, dense, high-energy soup of constantly colliding ionized protons and electrons.But as the expansion and cooling continued, radiation energy continued to decrease as compared to the rest of mass energy.


By around 400,000 years after the Big Bang, the temperature had dropped to two or three thousand kelvins—sufficiently low to permit electrons to be caught (deionized) into stable hydrogen iotas and for various hydrogen cores to shape the universe's first particles: hydrogen gas, or H2 . This period in the universe's early history is known as the recombination period. The cool thing about recombination is that it permitted the universe's excess radiation—generally high-energy photons and other subatomic particles—to decouple from issue and consequently to at long last travel, moderately unhampered, through  space. The universe became colder and more obscure over the course of the following not many hundred million a long time, a period which cosmologists have named "the dull ages." The leftover 3- kelvin sparkle of the early universe's euphorically liberated radiation energy, known as the Grandiose Microwave Background, can in any case be identified today.
Explore the birth of the Universe



Every dark age ends with a Renaissance, and the early history of the universe is no exception. Cosmologists believe that the so-called dark ages lasted about 100 to 200 million years, after which time molecular hydrogen and other molecules formed during the recombination era began to gravitationally clump together— perhaps from the effects of turbulence, but no one really knows why. The clumps of gas acted as seeds, gravitationally attracting more gas, making the clumps grow bigger and bigger until they eventually became enormous clouds of hydrogen that started to grow warm inside from the increasing pressure of the surrounding gas. Give a cloud a nudge—say, from the gravitational pull of another nearby cloud—and it will move and, eventually, start to spin. At some point, maybe 300 to 400 million years after the Big Bang, the temperatures in the centers of some of these huge, slowly spinning clouds of gas grew to be millions of degrees, as in the first three minutes after the big bang. The temperatures and pressures inside these spherical clouds became high enough to fuse hydrogen into helium, and the first stars were born. The dark ages were over!


From the Beginning to the End of Time

The first stars, now and then called Population III stars by cosmologists, weres omething other than eccentric nearby marvels, however. They were colossal—maybeone hundred to multiple times more huge than our Sun—and they had a
enormous effect on their heavenly area, transmitting massive measures of
energy out into the encompassing clusters and billows of hydrogen, warming them
remotely, and liberating the electrons that had been caught toward the start of
the dim ages. This time is known as the time of reionization, on the grounds that the universe
by and by started to shine—not from the light and warmth of creation but rather, as
today, from the light and warmth of the stars.



Everything about space

Cosmologists characterize a world as a gravitationally bound arrangement of stars, gas, 
dust, and other more baffling parts (see Dark Matter), all moving 
altogether through the universe as though they were a solitary item. When the first 
stars had framed, it was inevitable—very little time, truth be told—that 
a large number of them would unavoidably get drawn in by one another's gravity and 
structure bunches, at that point groups of bunches, and in the end colossal assemblages of 
stars circling their basic focus of gravity. 


Our own Milky Way world comprises of an expected 400 billion stars and has 
a design that is common of the class of supposed banned twisting systems seen 
all through the universe (see Spiral Galaxies). The Milky Way has a swarmed 
focal semispherical lump of stars encompassed by a compliment, winding formed circle of 
stars (counting the Sun), gas, and residue, which is all encircled by a diffuse 
round corona of more established stars, star groups, and two more modest friend worlds. 
It's a huge design, almost 100,000 light-years (the distance light voyages 
in a year, or around a billion miles) wide and 1,000 light-years thick in the 
plate. Our Sun is mostly out from the galactic focus, and one galactic year circle takes around 250 million Earth years. 


Space experts don't know precisely when the Milky Way was framed. The most established 
known stars in the universe are in the halo and are about 13.2 billion years of age. 
The most seasoned stars in the circle are more youthful—around 8–9 billion years of age. It is likely 
that the various pieces of the Milky Way framed at various occasions, albeit the 
essential design seems to have been gotten under way early. 
Our antiquated predecessors were awed by the splendid whitish band that overwhelmed 
their night sky, frequently imagining it in creation fantasies as a waterway of light and life. 
In spite of the fact that we presently realize that we are inside a gigantic, arranged assembling of 
stars watching out, it's still simple to discover wonderment in the scale and greatness of our home 


Solar Nebula

Star formation is a messy process. As giant molecular clouds collapse, almost all of the cloud’s gas and dust eventually falls into the central protostar—almost. A tiny fraction of the gas and dust remains in orbit around the forming star, and as the whole system spins and cools, that residual cloud of debris slowly flattens into a disk of gas, dust, and (farther from the star) ice. During this phase of star formation, it appears that all young stars start out with an accompanying disk, often called a solar nebular disk.


The nebula from which our own Sun eventually formed probably started collapsing about 5 billion years ago, though the exact timing is uncertain. Observations indicate that sun-like stars typically take about 100 million years to form, and that nebular disks form in only about 1 million years around young stars. Once the disk is formed, it changes rapidly, with tiny dust and/or ice grains colliding, sticking to each other, and growing into marble-size particles, in a process (called accretion) that computer models indicate takes only a few thousand years. These small particles collide with others, sometimes sticking together, and the process appears to continue on in a poorly understood, runaway fashion until, within perhaps only a few more million years, planetesimals (kilometer-sized clumps of dusty, icy, rocky, and/or metallic grains) and then asteroids 100–1,000 kilometers in size have formed.

Sun oriented nebular plates don't appear to keep going long; the vast majority of the residue accumulates or is scattered inside around 10 million years. Near the star, it's excessively warm for ice to consolidate, so the planetesimals are for the most part rough and excessively little to gravitationally 
clutch a lot of gas. Further away, ice and residue can be accumulated into bigger planetesimals, with enough mass to accumulate immense measures of gas too, in the end developing into "gas goliath" planets. Precisely how such untidy beginnings lead to such rich planetary frameworks, and in such brief period, is as of now a subject of much discussion and hypothesis among space experts.

When was time created?

Space artist Don Dixon’s conception of the proto-Sun and its solar nebular disk, the spinning cloud of gas and dust and ice from which all our solar system’s planets, moons, asteroids, and comets formed


Violent Proto-Sun

Star birth, like childbirth, can be a rather intense and messy event that involves a lot of energy. Even before they get hot and dense enough to start nuclear fusion of hydrogen into helium, newly forming protostars can emit huge amounts of energy as they gravitationally contract during their 100-million-year gestation period. Some of these baby stars funnel their energy into the solar system–size jets of gas, dust, and charged particles, possibly collimated and heated by strong magnetic fields from the star, or from material falling in from the associated nebular disk, or both.


Astronomers have identified many examples of violent jets of material being emitted from very young protostellar objects, often called T Tauri stars after the prototype example. In fact, the star T Taurus is very much like what astronomers believe the young Sun was like, suggesting that our own star went through a similar short and violent period of intense jetting and other high-energy activity before it started to stably fuse hydrogen and settle down into its long, relatively quiescent life on the so-called Main Sequence.
The deeper and more accurately astronomers peer into space, the more evidence they find for jets and disks around newly forming stars, suggesting that these features are a crucial part of star formation. A violent youth may be a normal, essential part of the life cycle of a typical star.



The temperature and pressure in the central region of the Solar Nebula grew dramatically for about 100 million years, until they passed a threshold where hydrogen atoms were packed so tightly that they underwent nuclear fusion, becoming helium and releasing some energy as light and heat. Thus, our Sun was born! We tend to think of the Sun as special, and rightly so—the Sun is critical to the creation and continuing survival of all life on our planet. It’s harder to think of the Sun as typical, average, even mundane, but in many ways it is. 


Our star is one of more than 10 billion trillion stars in the known universe, all of which appear to be the natural result of matter—mostly hydrogen —interacting with gravity at high pressures and temperatures and releasing enormous amounts of energy into their surrounding space. Stars are truly the engines of our universe. Once stars are born, they live relatively stable lives and then die, often in relatively predictable and sometimes spectacular ways. The Sun is no different. It will keep fusing hydrogen atoms into helium atoms for another 5 billion years or so. When the hydrogen runs out, the Sun will shed its outer layers (engulfing the Earth and the other inner planets) and start fusing helium in its core. When the helium runs out, the Sun slowly fades to a white dwarf and then dims to a cinder. Astronomers have been able to deduce that about one to three new stars are born each year, and about one to three old stars die each year in our Milky Way galaxy. If we extrapolate to all known galaxies and do a little math, that means that something like 500 million stars are born and 500 million stars die each day in the universe. It’s a staggering and humbling thought that should make us appreciate even more every one of these precious days in the life of our own star, the Sun.

An ultraviolet image of our local star, the Sun, taken by NASA’s Solar Dynamics Observatory UV space telescope. Streamers, loops, hotter spots (brighter), and cooler spots (darker) are all evidence of an extremely active, though quite typical, middle-aged star