Is the Big Bang in the Bible?

[Rusty Edge]

I thought you were suggesting I had a narrow view of energy. I can accept that. I didn't go to college( I went into a family business ), and my interest in space is mostly geographical, and my interest in science is primarily biology.

I was wondering what you were getting at. Matter as energy in motion? or something else?

I thought that if you suggested a new name for dark matter it would help me conceptualize it beyond a "sounds like a fudge factor theory to cover up some phenomena we don't understand"  term, in a ether/humors/poltergeist/   mythology kind of way.

What if  dark matter is  not something new, but some kind of an optical ( or other ) illusion in a retrograde planet / rainbow / rods/  mirage kind of way that calls for reconsidering the way light works ( or gravity, or time or magnetism or  waves  or whatever ) ?

That's what I'd investigate. I wouldn't say "Eureka! It's cold fusion!" when stuff doesn't add up.

I'd reconsider assumptions. Maybe there's room for improvement in one of the measurement methods on a cosmic scale in the new millennia. Or maybe there needs to be a new theory of time/matter/ energy.



So, how about a new name for dark energy?

[Buster's Uncle]

That's well-put Rusty; I've wondered myself if the universal expansion was a POV issue we've yet to wrap our heads around.

What would it look like from the inside of a black hole?  There's some reason to think the universe might be an in-falling black hole - I'd herd of this years before it got mentioned in the first episode of the Cosmos revival.

[Lorizael]

I was wondering when you guys would ask that. To answer the question of, "Why isn't dark energy anything else?" I'd suggest reading these four blog posts:

http://scienceblogs.com/startswithabang/2009/11/04/dark-energy-hard-to-kill-part/

http://scienceblogs.com/startswithabang/2009/11/05/dark-energy-gaining-a-foothold/

http://scienceblogs.com/startswithabang/2009/11/11/dark-energy-where-did-the-ligh/

http://scienceblogs.com/startswithabang/2009/11/30/dark-energy-beyond-supernovae/

They provide a good explanation of what the original observations meant, what else scientists thought they could mean, and why scientists are now very confident that those other explanations don't hold up.

[Buster's Uncle]

Ugh.  Homework. 

[Lorizael]

Additionally, this guy was going through grad school at about the time of the supernova discoveries. For several years, he (and many other cosmologists) did not believe that dark energy was responsible for the apparent accelerated expansion of the universe. But he eventually changed his mind as new evidence came in, and so did the cosmology community. Here's a good account of why he changed his mind.

http://scienceblogs.com/startswithabang/2012/07/19/one-does-not-simply-believe-in-dark-energy/

[Lorizael]

Basically, this idea that cosmologists haven't considered alternatives to dark energy is not supported by the history. Around the turn of the new millennium, cosmology journals were absolutely full of alternative explanations for the dimming of distant supernovae. The most plausible explanation was that some kind of dust was obscuring these distant supernovae and making them appear dimmer than they otherwise would be. But that (and other, less plausible explanations) were ruled out by further observations.

[Buster's Uncle]

Tell me about the Standard Candle, and why they think they can assume a set brightness for supernovae of a type - I've never gotten that latter.

[Lorizael]

The reason type 1a supernovae are thought to be reliable standard candles is because of the Chandrasekhar limit. This limit (backed by some very solid QM) is the point at which a white dwarf star becomes too massive for electron degeneracy pressure to resist its own gravity. The limit is about 1.4 solar masses.

Additionally, only a certain class of stars will ever evolve into white dwarfs, which means astronomers know what sorts of elements are going to be present in that star's spectrum. And if those stars ever go above the 1.4 solar mass limit (because of siphoning, or collisions, or other astronomical events), they will immediately explode.

What this means is that astronomers see a particular spectrum (because all white dwarfs originated as a similar type of star) at a particular brightness (because all type 1a supernovae will have 1.4 solar masses). This makes them very good standard candles.

[Buster's Uncle]

Okay, and why is reaching sufficient mass to collapse into a black hole, absent radiation pressure, a limit on supernovas?  Doesn't the Chandrasekhar limit pertain to star at the end of their fusion cycle?

[Lorizael]

It's not a limit on all supernovae, only type 1a supernovae. Basically, when they reach this limit, they begin to collapse, which increases temperature and density further, which allows for the fusion of the carbon in the star's atmosphere. This sudden burst of fusion causes a massive explosion that expels a giant chunk of the star into space.

[Buster's Uncle]

Yes, and everything from iron on up is a product of supernovas - we think.

I had understood that the explosion was more a product of bounce back from the collapse, but had wondered why that could last weeks...

[Lorizael]

What you're seeing weeks later is more the afterglow of the explosion than the explosion itself. The runaway fusion event creates a particular set of radioactive isotopes with half-lives in the days to weeks range, so they're able to glow for a long time after the initial explosion.

[Buster's Uncle]

When did the terminology change?  I would have sworn the phenomenon described with the white dwarf is what they used to call a plain ol' nova.

[Buster's Uncle]

I was wondering when you guys would ask that. To answer the question of, "Why isn't dark energy anything else?" I'd suggest reading these four blog posts:

http://scienceblogs.com/startswithabang/2009/11/04/dark-energy-hard-to-kill-part/

http://scienceblogs.com/startswithabang/2009/11/05/dark-energy-gaining-a-foothold/

http://scienceblogs.com/startswithabang/2009/11/11/dark-energy-where-did-the-ligh/

http://scienceblogs.com/startswithabang/2009/11/30/dark-energy-beyond-supernovae/

They provide a good explanation of what the original observations meant, what else scientists thought they could mean, and why scientists are now very confident that those other explanations don't hold up.

Additionally, this guy was going through grad school at about the time of the supernova discoveries. For several years, he (and many other cosmologists) did not believe that dark energy was responsible for the apparent accelerated expansion of the universe. But he eventually changed his mind as new evidence came in, and so did the cosmology community. Here's a good account of why he changed his mind.

http://scienceblogs.com/startswithabang/2012/07/19/one-does-not-simply-believe-in-dark-energy/

No sale.  Those are too short and skip too many steps to be convincing.  Still no explanation of what dark energy is, only what it's alleged to have done.  Not good enough.

My vote is something no one's thought of yet.

...I'm thinking about those braided rings of Saturn found by Voyager 1 in 1980 - Newton's laws are long-standing and rigorous, yet here was something they didn't even know was possible, and I don't believe the mechanisms are completely understood yet.  -Because the universe tends to be more complex than we imagine, and our observations will never be complete...

[Lorizael]

A nova is just a burp. It's when a white dwarf accretes enough matter on its surface to ignite some limited hydrogen fusion. This causes an explosion, too, but it's relatively minor and the star more or less remains intact.