Dark matter And dark energy

DARK MATTER AND DARK ENERGY

1. The concept of dark matter arises due to some of the unanswered problems of the working of the universe and its unnatural phenomenons .

2. First of all the light moving through the empty spaces usually bends .. light has the property to bend when ever passing through the medium .. this proves the existence of invisible non reacting matter .. A
3.Also this matter adds mass to the existing universe as the speed of the ordinary matter revolving around the galactic center must be different according to the existing physics but in reality the velocity of matter around the galactic center is same this prove the existence of large amount of matter around the galactic boundaries ..
4.next according to universal law of gravitation the universe must be contracting but when we observe the wavelength of the light using the concept of Doppler effect there must be a blue shift but in reality there is red shift which simply means the galaxies are moving apart but how this extraordinary repulsion of matter is possible there must be some sort of the energy responsible for this .. which is referred as dark energy.
5.Matter,as we know it Atoms,stars and galaxies ,planets and trees ,rocks and us.This matter accounts for less than 5% of known universe about 25% is dark matter and 70% is dark energy both of which are invisible .This is kind of strange because it suggests that everything we experience is really only a tiny fraction of reality ,We really have no clue what dark matter and energy are,or how they work.We are pretty sure they exists though So,what do we know ?
6. Dark matter is the stuff that makes it possible for galaxies to exist,when we calculated why the universe is structured the way it is,it quickly became clear that there's just not enough normal matter.
The gravity of the visible matter is not strong enough to form galaxies and complex structures.The stars would more likely be scattered all over the place and not form galaxies So,we know there is something else inside and around them ,Something that doesn't emit or reflect light ,something dark but besides being able to calculate the existence of dark matter we can see it kind of ,places with high concentration of dark matter bend light passing near by.So we know there's something there that interacts with gravity.Right now,we have more ideas about what dark energy is not,than what it is!
We know dark matter is not just clouds of normal matter without stars because it would emit particles we could detect.
7.Dark matter is not anti-matter,because anti-matter produces unique gamma rays when it reacts with normal matter.Dark matter is also not made up of Black holes,very compact objects that violently affect their surroundings,while dark matter seems to be scattered all over the place.Basically, we only know three things for sure.
->Something is out there.
->It interacts with gravity.
->There is a lot of it.
8.Dark matter is made up of a complicated exotic particle that doesn't interacts with light and matter in a way we expect,but right now ,we just don't know Dark energy is more strange and mysterious.
->We can't detect it,we can't measure it and we can't taste it.
But we do see it affects very clearly.
9. In 1929,Edward Hubble examined how the wavelength of light emitted by distant galaxies ,shifts towards the red end of the electromagnetic spectrum as it travels through space .He found that fainter,more distant galaxies showed a large degree of red shifts,closer galaxies not so much.

10.Hubble determined that this was because the universe itself is expanding ,The red shift occurs,because the wavelengths of light are stretched as the universe expands .More recent discoveries have shown that,the expansion of the universe is accelerating .Before that, it is thought that the pull of gravity would cause the expansion to either slow down or even retract and collapse in on itself at some point. Space doesn't change its properties as it expands; there's just more of it. New space is constantly created everywhere , galaxies are tight bound clusters of stuff held together by gravity so we don't experience in our daily lives. But we see it everywhere around us ,Wherever there is empty space in the universe , more is forming every second . So , dark energy seems to be some kind of energy intrinsic to empty space . Energy that is stronger than anything else we know and it keeps getting stronger as time passes by.

11.Empty space has more energy than everything else in the universe combined. We have multiple ideas about what dark energy might be. One idea is,the dark energy is not a thing ,but just a property of space.Empty space is not nothing , it has its own energy . It can generate more space and is quite active. So, as the universe expands ,it could we just more and more space appears to fill the gaps and this leads to a faster expanding universe. This idea is close to an idea that Einstein had back in 1917, of the concept of a cosmological constant a force that counteracted the force of gravity. The only problem is,that when we calculated the amount of this energy the result was so wrong and wired that it only added to the confusion . Another idea is that empty space is actually full of temporary virtual particles that spontaneously and continually form from nothing and then disappear into nothing again.The energy from those particles could be dark energy. Or maybe dark energy is an unknown kind of dynamic energy fluid or field which permeates the entire universe ,but somehow has the opposite effect on the universe than normal energy and matter but if it exists,we don't know how and where or how we could detect it.So there are still a lot of questions to answers Our theories about dark matter and dark energy are still just that;
12.On one hand ,this is kind of frustrating ,on the other hand this is frontier science making it very exiting .It shows us that no matter how much we feel we're on top of things,we are still very much apes with smartphones ,on a tiny fragile island on space looking into the sky wondering how our universe works .There is so much left to learn ,and that is awesome.
Do feel free to ask questions i will try to post the solution of all your queries.
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All Blackholes Are Going to Die?

DEATH OF A BLACKHOLE

So is it true..??

In true sense it is true that some day not now every black hole is going to die .. with the die it means decompose it can be due to the fact of hawking radiations ..due to our respected astrophysicist Stephen hawking we came to know that nothing in this universe is ever lasting weather it is blackhole or galaxies

Gamma Ray bursts

gamma-ray astronomy, gamma-ray bursts (GRBs) are extremely energetic explosions that have been observed in distant galaxies. They are the brightest electromagnetic events known to occur in the universe.Bursts can last from ten milliseconds to several hours.After an initial flash of gamma rays, a longer-lived "afterglow" is usually emitted at longer wavelengths (X-ray, ultraviolet, optical, infrared, microwave and radio).The intense radiation of most observed GRBs is thought to be released during a supernova or hypernova as a rapidly rotating, high-mass star collapses to form a neutron star, quark star, or black hole. A subclass of GRBs (the "short" bursts) appear to originate from a different process: the merger of binary neutron stars. The cause of the precursor burst observed in some of these short events may be the development of a resonance between the crust and core of such stars as a result of the massive tidal forces experienced in the seconds leading up to their collision, causing the entire crust of the star to shatter.The sources of most GRBs are billions of light years away from Earth, implying that the explosions are both extremely energetic (a typical burst releases as much energy in a few seconds as the Sun will in its entire 10-billion-year lifetime)and extremely rare (a few per galaxy per million years[8]). All observed GRBs have originated from outside the Milky Way galaxy, although a related class of phenomena, soft gamma repeater flares, are associated with magnetars within the Milky Way. It has been hypothesized that a gamma-ray burst in the Milky Way, pointing directly towards the Earth, could cause a mass extinction event. GRBs were first detected in 1967 by the Vela satellites, which had been designed to detect covert nuclear weapons tests. Following their discovery, hundreds of theoretical models were proposed to explain these bursts, such as collisions between comets and neutron stars. Little information was available to verify these models until the 1997 detection of the first X-ray and optical afterglows and direct measurement of their redshifts using optical spectroscopy, and thus their distances and energy outputs. These discoveries, and subsequent studies of the galaxies and supernovae associated with the bursts, clarified the distance and luminosity of GRBs, definitively placing them in distant galaxies.

After how many years all the blackholes are going to vanishe up??

Now this is a very slow process .. so it will take billions of years as there is huge no of stars in our universe so there will be continuous production of the black holes as these stars will take a long time die and still there is enough star dust so that the production of the star will be ongoing for several million years ...So first all the stars start dying which it self will take millions of years there after red dwarf will govern the universe .. then the era of complete darkness will start where there will be every few starts as a red drawft or white dwarf with very low luminous intensity leading to the darkness .. there after there will be decline int no of here stars .. then the era of black holes will starts where there will be complete darkness with the blackholes sucking everything.

So what will be the reason for the pause in the formation of stars and hence blackholes ??

Here the concept of dark energy arises ...commonly we were only taught about gravitational forces .. but gravity is not the only thing .. for the year scientists believes that universe will die as a big crunch due to the gravity everything is going to merge .. but practically universe is expanding so whats the reason behind this .. it is Dark energy the energy which which keeps pushing things apart due to star formation is slowing down and there will the time where there will be no possible star dust for the formation of the stars .. leading to the dark world

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BLACK HOLES | Birth of a blackhole | why can't we see a blackhole | felling into a blackhole.

Blackholes

So first have a look at how does a black hole looks like :-

Birth of a black hole

It just starts when a massive star runs out of fuel and due to massive size resulting into uneven or we can say heavy gravitational pull of the metallic core of the star it just collapse into the core due to large graviational pull of the core .. if the size of the star is large enough to take the density of the collapsed star upto damn high it just form dense ball like structure with a density of like earth collapsed into egg

Why can't we see a black hole

Well we can't clearly say that... but yes they are not visible still their presence can be easily identified.

By gravitational lensing
Gamma ray brusts
hawking radiations

So why they are not visible .. simple reason is that they bend space-time way too much that light cant even escape from it thats the only reason why we are still not able to find out what's inside event horizon

What if we accidently fell into a black hole

It could happen to anyone. Maybe you're out trying to find a new habitable planet for the human race, or maybe you're just on a long walk and you slip. Whatever the circumstances, at some point we all find ourselves confronted with the age-old question: what happens when you fall into a black hole?

The outermost boundary of the hole is its event horizon, the point at which the gravitational force precisely counteracts the light's efforts to escape it. Go closer than this, and there's no escape. The event horizon is ablaze with energy. Quantum effects at the edge create streams of hot particles that radiate back out into the universe. This is called Hawking radiation, after the physicist Stephen Hawking, who predicted it. Given enough time, the black hole will radiate away its mass, and vanish. You might expect to get crushed, or maybe torn to pieces. But the reality is stranger than that.

Now Without waiting lets just dive into a blackhole ..near the blackhole you are able feel a small stretch on your body but still you can use you cell phone flash to single ... but by the time reaches near the event horizon .. you got freezed there as the time stops there to the curving of spacetime .. if you wanted to see whats next if you somehow managed to go more deeper then your body will be converted into ashes as soon as you got exposed to blazing hawking radiations

How big Blackholes actually are ?

Black holes can be big or small. Scientists think the smallest black holes are as small as just one atom. These black holes are very tiny but have the mass of a large mountain. Mass is the amount of matter, or "stuff," in an object. Another kind of black hole is called "stellar." Its mass can be up to 20 times more than the mass of the sun. There may be many, many stellar mass black holes in Earth's galaxy. Earth's galaxy is called the Milky Way. The largest black holes are called "supermassive." These black holes have masses that are more than 1 million suns together. Scientists have found proof that every large galaxy contains a supermassive black hole at its center. The supermassive black hole at the center of the Milky Way galaxy is called Sagittarius A. It has a mass equal to about 4 million suns and would fit inside a very large ball that could hold a few million Earths.

Could a Blackhole have sufficient energy to destroy earth?

Black holes do not go around in space eating stars, moons and planets. Earth will not fall into a black hole because no black hole is close enough to the solar system for Earth to do that. Even if a black hole the same mass as the sun were to take the place of the sun, Earth still would not fall in. The black hole would have the same gravity as the sun. Earth and the other planets would orbit the black hole as they orbit the sun now. The sun will never turn into a black hole. The sun is not a big enough star to make a black hole

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