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Asked by Giller_98 to Colin, John, Kevin, Shikha, Triona on 8 Nov 2014. This question was also asked by mnormanly, 582bera34, Emily.
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Shikha Sharma answered on 8 Nov 2014:
Hi Giller,
Our universe is made up of enormous and indescribable expanse of dust, gas, stars, galaxies, and life. As per the most acceptable theory, the universe is made of 4% regular normal matter, 23% dark matter and 73% dark energy.
Normal matter consists of the atoms that make up every visible object in the Universe.
Dark energy is believed to contribute a major part in Universe but its nature is completely unknown. It pushes galaxies farther apart and thus is believed to contribute to the expansion of the Universe.
Dark matter is something which cannot be seen directly and it cannot be detected from the light which it emits or it fails to emit light. Its presence is inferred indirectly from the motions of astronomical objects. It is generally used to explain how groups of objects function together.
Our lovely planet, the Earth seems really gigantic but in the Universe as a whole, it is a tiny like a fragment of rock. So, now you can imagine how big Universe is…
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Kevin Motherway answered on 8 Nov 2014:
The 3 most beautiful words in science: we don’t know! Cosmologist have got this one spectacularly wrong over the last few years. The Big Bang goes off, so the universe starts expanding and expanding, but at the same time we’re told gravity attracts things to each other, that’s how planets, stars and galaxies form right? But thanks to the Hubble telescope in 1998 it was revealed that very distant old stars showed a slower rate of expansion from each other than we see today. Woooooah. In other works the expansion of the universe is speeding up. Thats like throwing and apple up into the air and instead of reaching a high point and falling back down into your hand, instead it keeps going up into the air getting faster and faster, leaving the planet and continuing on into space accelerating up to light speed.
Red faces all round. “How are we going to explain this one guys?”. “Well we can’t see what’s causing this”.
“Cmon guys no idea is too stupid. Somebody come on, we’ve got grant applications to fill in here. My kids need braces and the electricity bill is due. Cmon somebody an idea”
” Well. Einstein was a little bit unhappy with one of his theories of gravity and used a fudge factor called the Cosmological Constant to explain that even empty space could have a form of energy and matter to explain away the mathematical difficulty in his theory. We could use that maybe?”
“Brilliant. You’re a genius. Let’s call it “Dark Energy” and “Dark Matter” and we can spend the next few decades looking for that.”
“What is it though?”
“We don’t know silly. We’re scientists it’s our job to observe; try and predict something; Observe and see how our predictions fit the data and keep going until we crack it. To the telescopes!……..oh yeah we can’t see it, can we. Get filling out those grant applications for a dark matter detector….what do you mean you can’t buy one….build one!…..invent it ! ………”
And so it continues….more Scientists needed. Please apply!
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