PC Pals Forum
General Discussion => Science & Nature => Topic started by: GillE on June 15, 2010, 13:20
-
Dark energy may not exist in space, scientists claim (http://www.telegraph.co.uk/science/space/7827674/Dark-energy-may-not-exist-in-space-scientists-claim.html)
I reckon it's an interesting article. I just wish I understood it :laugh: !
-
Sam, we need an interpreter! :)
-
It's something many of us have suspected for a long time Gill. But there again who among us would not have pooh-poohed quantum theory when it was first postulated? ;D
-
You understand it, Clive?
I would never have pooh-poohed quantum theory, but then again, I wasn't asked o:) .
-
that article really does say anything though - scientific reporting always seems to miss any actual data or analysis. I'll have to read the paper at some point.
I've always been a bit of a skeptic of dark energy, not so much the dark matter though - as observations are pretty solid.
-
Dark matter is a given otherwise Newton is wrong. :laugh:
-
It's a bit late to tell him now, Clive. ;D
-
But doesn't matter have mass, and where there's mass there's energy? Something about e=mc2?
Oh, where's Doctor Karl when you need him?!
-
I'm sure Dr. Sam will be along soon. ;D
-
Well, yes matter implies energy.
Dark Matter and Dark Energy should not be confused, they are two different things completely. They just have been given the term dark cause we can't directly observe them.
"Dark matter" is inferred to exist based on observed gravitational effects on visible matter and background radiation. The evidence for this is a lot more solid than that of Dark Energy - though some people have suggested we just have gravity wrong or we just dont have sensitive enough telescope to find the normal matter. Essentially dark matter means it does not radiate electromagnetically. Dark matter was postulated by Fritz Zwicky in 1934, to account for evidence of "missing mass". He is quite an interesting character, but that's a discussion for another time. The majority of the dark matter in is believed to be nonbaryonic, that is it contains no atoms and does not interact with ordinary matter via electromagnetic forces (an example would be a neutrino). This is where CERN is important for astrophysics.
"Dark Energy" - is essentially a fudge factor. The mistake that Einstein made and actually went on to make some sense, maybe. The most common form is the cosmological constant, a constant energy density filling space homogeneously.
-
Maybe I should add this, when we talk about e=mc^2 we really are talking about the conversion of mass not matter to energy. I know its pedantic but it should be pointed out. Actually a good read on this is: http://plato.stanford.edu/entries/equivME/#2
-
That should keep Gill busy for a while. :)
-
You have provided as good an explanation of the dark side as I have ever seen Sam. You should write a book on the subject. :D
-
That's a wonderfully clear explanation, Sam - thanks :) . I'll have a look at your link later tonight. As Simon says, it will keep me busy!
I looked up Fritz Zwicky on Wikipedia and he does indeed seem to have been quite a character!
-
Great name too!
-
I looked up Fritz Zwicky on Wikipedia and he does indeed seem to have been quite a character!
he had a phrase if he didn't like you - he called you a spherical b*****d, which means you are a b*****d in every direction!!
-
Or a load of old balls? ;)
-
:laugh: