Big bang theory of the Universe ?

Question

How has it been conclusively proved that the universe was created as per the Big Bang theory due to an expansion?

How can it be said that the universe was extremely small and extremely dense? What caused it? What happened when it expanded? What caused celestial objects to be formed? Why stars and why planets and solar systems and galaxies?

Answer 1

There are many proofs about the Big Bang theory.

we all know, that the universe is expanding. (this is proved by the redshifts in the spectrum of stars). now, if you work that expansion backwards, you will end up in a hot and dense primevial atom. this is what happened --- the atom got denser and hotter, and denser and hotter and denser and hotter. eventually it became so dense and hot, that it exploded, ejecting its mass, and hence, forming space. the high temperature and and density of the ejected particles caused fusion among the particles. they kept on fusing, as the temperature cooled downed (this happened at the atomic level). as it cooled down, things went to the submicroscopic level, and eventually to the macroscopic level. particles collided with each other, and this series of collisions happened for ages, untill what we know it now as the 'space matter' was created.

the 'story' goes on and on.....

however, a drawback of this theory is that it did not explain what made the atom so dense and hot.

Answer 2

Arnold, please read up on the Big Bang and the scientific use of the word theory. Scientists don't make a habit of "conclusively proving" anything, they simply devise better and better theories with better and better data. The fact of the matter is, the overwhelming body of data demonstrates that the Big Bang theory is satisfactory, if not yet complete, model for the creation of the universe.

Answer 3

You need to see this show on the History channel that I watch all the time, it's called "Universe" and it's thoroughly enjoyable, per me!  I love documentaries, or documentary type "things"!

But it explains all  the "stuff" you're asking about!  Watch it, I think you'll enjoy it!

Answer 4

It has not been conclusively proved that the universe was created through Big Bang theory otherwise it will not be called theory anymore. This, I believe, will never be conclusively agreed.

Answer 5

Big Bang theory hasn't been conclusively proved, hence the word 'theory'. As with any other scientific theory, it is based on evidence and like previous answerers have said, there is enough evidence to support this theory. That doesn't mean it is definitely right... just that at this moment in time there is sufficient evidence to point towards that conclusion.

As for all your other questions, find a book and read up about it!

Answer 6

There is substantial observable physical evidence that supports the Big Bang theory (for example cosmic microwave background radiation, expansion of the universe evidenced by redshift in spectra of distant galaxies, etc.).

As for your other questions, answering them is well beyond the space of this forum.  Read a good book on the subject (Bang! The Complete History of the Universe by Brian May et.al., or Brief History of Time by Stephen Hawkins).

Answer 7

Why does everyone obsess about the Big Bang?  Its a very nice theory about something that happened very very long ago.   I'm happy to assume it took place unless the majority of scientific opinion says it didn't.  In that unlikely event  I'll change my mind and I'll believe in the new and improved theory.  

This may sound seriously wishy-washy but my highest math is college algebra and trig.  My highest physics and chemistry were courses for non-majors.  These are not precisely the prerequisites for independently coming up with a new theory or judging existing ones.  And I don't presume to claim knowledge of anything more than the barest outline of the event.

The truth is it simply isn't important in our lives.   Presumably it took place 13.8 billion years ago.  Eukaryote cells only evolved one billion years ago.  13.8 BY defies understanding.  Only cosmologists and a sprinkling of astronomers, physicists and theologians should care about such things.  Leave it to them.  Be happy, don't worry.  

Answer 8

You need to study the study the formation of the Universe, the formation of galaxies and our own solar system and know what a singularity is!

Answer 9

Well, people don't exactly know why the universe was once a small

singularity and for some reason exploded, and there is evidence of the Big Bang happening, and the alternative to believing the Big Bang is believing "God" created the universe, and there is no proof of that.

Answer 10

Islam and Holy Qur'an tell us about Big Bang 1400 years back.

Answer 11

"...How has it been conclusively proved that the universe was created as per the Big Bang theory..."

It hasn't been proven conclusively. That's why it's still called the Big Bang *theory.*

"...How can it be said that the universe was extremely small and extremely dense?..."

Observational evidence supports this in that all major structures in the observable universe are moving away from each other. It's logical then to run the clock backward to a time when these structures -- at least the energy that would produce them -- was concentrated into what's known as a singularity.

"...What caused it?..."

Totally unknown, although there are a number of concepts that could work, particularly what's known as vacuum or zero-point energy.

"...What happened when it expanded?..."

The universe began to cool as its space enlarged. For about the first minute of the Big Bang it's believed that nothing existed but space and extremely high temperatures. After about 1 minute the universe had cooled enough for the first neutral atoms to begin forming.

"...What caused celestial objects to be formed?..."

Gravity! At first the universe contained mostly hydrogen gas. Within this gas were regions of higher concentration and it's there that gravitational interaction between particles started clumping together. Eventually the first stars formed, then the first galaxies, etc.,.

Answer 12

The *idea* of the big bang has been proven. We know it started like the theory says... we know its expanding like the theory says.. we don't know if some of the steps it lists are true. But its safe to say the big bang theory is completely correct we just need proof. Edwin Hubble showed that the universe was expanding by proving that galaxies were moving away from each other.

We can say that the universe was once extremely small and extremely dense because we know its expanding. Its like a balloon being blown up... it starts small, and dense. When you blow it up, it expands. Make sense?

There are a whole range of theories trying to explain what caused it. I just got through answering a question asked by "Adam" about the big crunch. Look at my answer, I discuss the big crunch there. Its a couple questions above yours on the astronomy forum. The big crunch basically says it is a continuous cycle of the universe expanding, shrinking, crunching, and then being created again.

The universe expanding allows time to move forward in a way. Time and space are intertwined... that's why we call it "space-time". When space moves forward, time does too. But this is kind of out there. The expansion of the universe does cause galaxies to move away from each other... that's the most noticeable effect.

Celestial bodies in the universe were formed after elements condensed because of gravity and because they cooled down. They just happened to form Earth by chance. Boy aren't we luck? The first stars and galaxies formed about 1 billion years after the big bang.

Stars formed first... left over matter formed planets and asteroids.... all of these things started to orbit common centers of extreme mass and therefor extreme gravity causing galaxies to form.