Prakash World's

This is the basic equation of cosmology, and its solution tells how universe will evolve on large scales. We can derive it using Newtonian approximation, if we accept two results from General Relativity: First, there is, so called, Birkhoff's ,theorem, which says that, for a spherically symmetric system, the force due to gravity at some radius is determined only   by the mass interior to this radius. And also, the energy contributes to gravitational mass density. So we need to add them up together. Imagine a sphere with a mean density of row, radius of R, acceleration to a particle in surface, which is the second derivative of the radius, is given by formula.                 Ȑ = - 4 л G ϱ R                          3 Now, if the density changes, it c...

The beginning of the universe started with the cosmic background , which gets us back to the stage when the universe was 380,000 years old . Then, original chemical elements, found that helium had been formed when the universe was only three minutes old . Than dark matter got us further back when the time of the universe was like a ten billionth of a second , and Higgs boson frozen into the universe when it was only like a trillionth of a second . Antimatter , if this idea with the neutrinos would work out, gets us back to the very beginning, right after the inflation, we don't know exactly what the time scale is. the inflation itself when the for the structure we see today, that led to the formation of stars and galaxies , that right at inflation , and that's as far as we can get back to the beginning of the universe right now. Now we'll switch our gears to think about the future of the universe. And that's one of the really basic questi...

The Higgs boson particle can be argued as one of the most phenomenal discoveries in this 21st century. A particle which was previously theorized to exist, Mr. Peter Higgs proposed this idea that universe has Higgs Boson stuck everywhere that was already like 50 years ago but scientifically discovered in March 14 2013. The search for this particle was inspired by some fundamental questions in particle physics; such as why certain particles have mass when the symmetries controlling their interactions should be massless.  For more than 40years, scientists have searched and experimented to uncover this elusive phenomenon and the particle which may have induced mass in these molecules. This prolonged and frustrating search would lend the name 'Goddamn particle' to the Higgs Boson particle which is now shortened and called the 'God particle' after its discovery. The Higgs Boson particle is named after Peter Higgs, one of the 6 scientists who hypothesized the exi...

Cosmic Expansion We can observe cosmic microwave background at least we would like to know the mathematics behind this expanding universe. The expanded universe itself is governed by the force of gravity, Einstein's theory of general relativity . So according to Einstein, it's actually simple thing. It's like we keep a ball in our hand. We stand on the surface of the earth and throw it upwards, and initial thrust is the big bang. The way a ball keeps going up is the expansion of the universe. Now imagine if we throw a ball with a high speed it would eventually go up, slows down and stop, and come back down. Maybe the universe would do the same thing. It may start expanding, but at some point stops, and would come back down, and collapse. So that's one possibility for the fate of the universe. But as far as we can tell, anything that goes up should slow down, at least. So that's the equation for the cosmic expansion. Imagine the entire uni...

In the energy of the universe, dark matter makes up about 25%, a quarter of the universe. Antimatter doesn't seem to exist in the current universe. If we look at the solar system, all the planets revolve around the sun. But it's velocity is fixed by the distance from the sun. It goes down, like one over square root of the distance. Each planet is moving at a pretty high speed around the sun. As we go farther and father away from the source of gravity. Because the gravity gets weaker by inverse square root, its reverse revolution velocity should become slower. So that's what we see in this situation. In the solar system. But if we look at the scale of the galaxy, and this is our own galaxy. Our solar system is away from the center by 28,000 light years away. It doesn't seem to be the case. Our solar system is moving actually very fast, much faster than the entire source of gravity coming from the stars combined would support us. So something el...

When the Mr. Peter Higgs proposed this idea that universe has Higgs Boson stuck everywhere that was already like 50 years ago. People started contemplating doing an experiment to prove this theory that was like also 30 years ago. When we look into outer space, much of it seems completely empty but particle called the Higgs boson is frozen into this empty space. That is actually much needed for us to understand the origin of atoms. The discovery of Higgs boson came out from an experiment called Large Hadron Collider laboratory that's in international research center called CERN which is on a border between Switzerland and France, and they have built this big tunnel which is as big as 27 kilometers in circumference. It's a big tunnel, which is filled with high tech equipments. The basic idea is that by building this big experiment can accelerate particles like protons during incredible speed and energy smash together to recreate the condition of the Big Bang. ...

Once we have this blob of dark matter , gravity force the ordinary gas in and it starts to form this cloud of gas , or the molecular cloud, and the core of the molecular cloud further collapses and start producing something rather dense that would eventually become a star . We can reproduce this process in a computer disc days . If we go further with this computer simulation , then this initial form of star would start to accumulate more stuff from outside , by a gravitational pull. But once they start accumulate so densely , and then it starts to actually eject it off. It was sort of blowing out , by the reaction, so that's something we can see in computer simulation , so for a while dust just settles on the surface of this protostar . It's not quite a star yet , but as it keeps accumulating on the surface , we see this ejection of material , in the polar direction . So it stops growing at that stage, because whatever settles in further gets blown out , so...

Well we can do, again going back to this sort of prism , by measuring the spectrum of colors coming from star , we see these lines, which shows some colors are missing. This is called spectroscopy, which is very important technique in studying the astronomical objects. This particular star, which is actually our sun , has a lot of these lines which shows that is has many heavy elements. These stars are called population one , a lot of metals , elements heavier than helium . This is clearly contaminated by the past supernova explosions. If we look hard enough, sometimes we find stars which seem much cleaner.Less contamination of these heavy elements . So they are called population two stars. If you go way back into the beginning of the universe , there must have been what is called population three stars which are made of Hydrogen and Helium alone , without any contamination from the previous generation of stars. We haven't found those, but people s...

The big bang produced only hydrogen, and helium , and no other heavy elements that lead to the formation of force stars , and inside the stars you form. Bigger elements like carbon, oxygen, silicone , all the way up to iron , and as long as these elements are stuck inside the stars, we still don't get to use them to form a body, so it doesn't explain where we came from. These stars can actually explode at the end of their life that would release a lot of stuff back into the outer space. At the core of these stars gets released like carbon, nitrogen, oxygen and iron that eventually form a body. So what is believed is that our sun is probably the third generation star. So we had the initial stage of the star formation based on the hydrogen heating alone. Some of it exploded, which leads to more stuff, reach the end of life exploded , and the sun use that kind of material to form the initial core of the star. So the explosion star , li...

But the most important thing is that the star's form bigger and bigger chemical elements. The sun burns hydrogen to build helium . That can happen even in a very smallish star , like the sun , the hydrogen can go to helium . In the case of the sun, it can probably go all the way up to carbon it will bring in three helium nuclei together fuse them into carbon . That is going to happen in the sun as well after it comes very close to the end of its life when it runs out of the hydrogen fuel. But it’s believed it doesn't go any beyond that. We need much bigger and more massive stars to let the reaction go further. By going from carbon to neon and silicon and iron we can keep building up heavier and bigger elements by using the inner core of bigger stars . If you take some example of a typical star which goes all the way down to iron, the time scale is actually not that long . Hydrogen burning may last like only like seven million years...