What is the evidence?

[Nefer-Ankhe]

There are a lot of theories associated with space and the universe, some I always hear/read about, but never really understood the theories basis. Just a few questions I have...

What is the evidence/or basis for the theory that the universe began via the big bang? What if the universe always was and always will be?

How do they "know" the universe is continuously expanding at a extremely fast rate?

How do they "know" the universe is approximately 13 billion years old? In the grand scale of things, 13 billion years seems to be rather an insigificant age.

How do they "know" yellow suns only last approximately 10billion years before exploding into a massive red sun?

Furthermore, how do they "know" our yellow sun has been around approximately 4.5 billion years (leaving it to have approximately 5.5 billion years before exploding and consuming our planet as we know it 'Earth').

All these questions I am very interested in and there answers.

Thanks in advance.

[spacecowboy342]

I think the evidence starts with the work of an astronomer named Edwin Hubble back in the 1920's who discovered there were other galaxies besides the Milky Way and that they were moving away from us and the further away they were the faster they were moving away. He could tell this from the red shift of the light from them that reaches us. If they are getting farther apart as time goes on then it would follow that in the past they were closer together and wind the clock back far enough and they all come together at one point. One piece of evidence that the Big Bang occurred is the Cosmic Microwave Background radiation which is thought to be the left over traces of the BB.

[Davros of Skaro]

Neil Degrasse Tyson evidence for the "Big Bang" for the layperson.

https://www.youtube....h?v=JvAmABvcd5Q

Edited January 25, 2014 by davros of skaro

[taniwha]

No one can prove the universe was created by a big bang . No one has been able to stretch their brain far enough yet to dispel that contention. it is still possible to agree with at the same time. But for me to explain would take ages lol.

Yes the universe has always existed, even if you prefer the big bang theory.

[spacecowboy342]

No one can prove the universe was created by a big bang . No one has been able to stretch their brain far enough yet to dispel that contention. it is still possible to agree with at the same time. But for me to explain would take ages lol.

Yes the universe has always existed, even if you prefer the big bang theory.

No one can prove that either. But then science isn't really in the business of proving things true. It proves things false and looks for truth in whatever is left. This is why the BB is a theory as is evolution and atomic theory etc. No matter how much evidence might seem to support a theory there is never 100% certainty in science. (Except maybe in mathematics) All it takes is one bit of counter evidence to disprove a theory, which is why to be science a theory must be falsifiable. To say anything existed before the BB or whatever other origin theory you might propose is, I think, unfalsifiable, and is not science but philosophy.

[taniwha]

No one can prove that either. But then science isn't really in the business of proving things true. It proves things false and looks for truth in whatever is left. This is why the BB is a theory as is evolution and atomic theory etc. No matter how much evidence might seem to support a theory there is never 100% certainty in science. (Except maybe in mathematics) All it takes is one bit of counter evidence to disprove a theory, which is why to be science a theory must be falsifiable. To say anything existed before the BB or whatever other origin theory you might propose is, I think, unfalsifiable, and is not science but philosophy.

Cheers . Mathematics as a universal measure huh? hmmm nice philosophy.

to be science a theory must be falsifiable.

Some more nice philosophy. ? lol

So all I did was answer the OP in the same flavour the question was asked. Im confused. Did anyone mention science.

The OP asks What if the universe always was and always will be

Not only do I agree with that philosophy but I believe that the universe we know fits precisely that model already. One way that expansion might be explained is the resultant force of absolute compression. If two states exist which oppose each other then any resultant collision leads to creation, like a thunderhead emitting electrical energy in a storm, or an atom in a collider. You need friction as ignition.

[spacecowboy342]

Cheers . Mathematics as a universal measure huh? hmmm nice philosophy.

Some more nice philosophy. ? lol

So all I did was answer the OP in the same flavour the question was asked. Im confused. Did anyone mention science.

The OP asks What if the universe always was and always will be

Not only do I agree with that philosophy but I believe that the universe we know fits precisely that model already. One way that expansion might be explained is the resultant force of absolute compression. If two states exist which oppose each other then any resultant collision leads to creation, like a thunderhead emitting electrical energy in a storm, or an atom in a collider. You need friction as ignition.

not philosophy but the scientific method. And yes mathematics is a "universal measure". And the OP was asking for evidence of Big Bang theory in a forum on astronomy and astrophysics which would lead me to the assumption we were talking about science. Feel free to believe what you wish about the universe being eternal, but where is the evidence?

[taniwha]

not philosophy but the scientific method. And yes mathematics is a "universal measure". And the OP was asking for evidence of Big Bang theory in a forum on astronomy and astrophysics which would lead me to the assumption we were talking about science. Feel free to believe what you wish about the universe being eternal, but where is the evidence?

lol. no worries I misunderstood the context of the question. You are right.

I think an eternal universe speaks for itself. I will continue discussion in the philosophy section I will start a new topic cheers.

[Peter B]

There are a lot of theories associated with space and the universe, some I always hear/read about, but never really understood the theories basis. Just a few questions I have...

What if the universe always was...

The reason scientists lean towards the Big Bang Theory rather than a universe that "always was" is simply that this is where the evidence all seems to point.

...and always will be?

Well, the current evidence suggests the universe probably will, er, "always will be". Until about 10-20 years ago it was unclear whether the universe would continue to expand or collapse back into itself. Thanks to careful measurements, it seems the rate at which the universe is expanding is increasing. In the way distant future, there will eventually be no more material to make new stars and planets; further into the future the last stellar remnants will chill down towards Absolute Zero; and even further into the future matter itself will break down and black holes will evaporate. Eventually (in something like 10¹⁰⁰ years) the universe will consist of energy and fundamental particles at the tiniest fraction of a degree above Absolute Zero, so evenly spread that Nothing will Happen.

In the grand scale of things, 13 billion years seems to be rather an insigificant age.

To you, maybe. To me it's a number hard to visualise. For example, if the universe's age was scaled down to one year, the lifespan of a typical human would be about 1/6th of a second.

How do they "know" yellow suns only last approximately 10billion years before exploding into a massive red sun?

Furthermore, how do they "know" our yellow sun has been around approximately 4.5 billion years (leaving it to have approximately 5.5 billion years before exploding and consuming our planet as we know it 'Earth').

The process of stellar evolution was mostly worked out in the 1930s to 1960s although new discoveries are being made all the time.

My understanding is that our knowledge of the Sun comes from learning about the elements which are in different stars (spectroscopy), understanding the nuclear processes which operate in the universe (which radioactive elements decay into which daughter elements, and at what rates), and studying all the stars Out There which are seen to be at different stages in their lives. As a result astrophysicists were able to build their understanding of stellar evolution - the birth, ageing and various deaths of stars, all of which depend on their size.

All these questions I am very interested in and there answers.

Thanks in advance.

I'd strongly recommend the Wikpedia pages on topics like stellar evolution and the age of the Earth. Obviously Wikipedia shouldn't be relied on as a perfect source, but it's usually a useful place to start.

Otherwise you can mosey on down to your local library or bookshop and search out books on these topics. There are likely to be plenty of introductory books. "Coming of Age in the Milky Way" by Timothy Ferris and Bill Bryson's "Brief History of Nearly Everything" are two I can recommend. Both tell the story of how we've come to know what we know, which helps explain why we know what we know (as opposed to simply telling you what we know). Plus Bill Bryson is just simply a great writer.

[spacecowboy342]

[Almagest]

Nothing to add except I want a vest like that!

[Xynoplas]

Science is merely the interpretation of data. If you come from a background that assumes, say, Genesis, then you're going to go out and try to find the "beginning", and you will subconsciously make sure you find it.