Hold on to your propeller hats for this one.
A new model of the universe claims that not only is Dark Energy superfluous but also that the Big Bang never happened meaning the universe may have no beginning and no end.
Wun-Yi Shu at National Tsing Hua University in Taiwan has recently posted a study at arXiv.org explaining this idea which I am now going to try to do some justice to. Wish me luck.
First a bit of background.
We all know what the big bang is right? …well, I don’t care, I’m going to sum it up anyway:
The Big Bang describes the birth of the universe billions of years ago as a titanic spacetime explosion creating everything we know. This has successfully explained lots of observed phenomena such as the following:
- At huge scales everything is moving away from everything else at increasingly fantastic speeds…Hubble, expansion of the universe and all that right?
- There is this Cosmic Microwave Background radiation suffusing the universe that is suspiciously identical to what we would expect from the ancient afterglow of this explosion.
Put these two ideas together plus a host of others and it seems damn likely that the big bang really happened
A more recent theory made world headlines in the past decade claiming that by studying classes of supernovae it has shown that the universe is not only expanding but it is expanding at an accelerating rate. The source of this expansion was a mystery and still is today so they gave it an equally mysterious name to describe it…DARK ENERGY!
Professor Shu’s theory does away with both the big bang and dark energy and a couple of other problems.
He does this by declaring that the speed of light and the gravitational constant of the universe vary over time depending of the evolution of the universe.
This has been postulated before but the kicker here is that as these values change…, time and space are slowly converted into on another.
The same is true for mass and length as well. One changes into the other over time.
“We view the speed of light as simply a conversion factor between time and space in spacetime, It is simply one of the properties of the spacetime geometry. Since the universe is expanding, we speculate that the conversion factor somehow varies in accordance with the evolution of the universe, hence the speed of light varies with cosmic time.”
So, big picture….as the universe continues to expand, time is changed into space and mass is converted into length. When the universe contracts, the opposite happens.
My take then is that the universe continually expands and contracts depending on the relative values of space, time, mass, energy, length
So the ever increasing expansion of the universe can be explained by these varying relationships and there is no need to invent a mysterious dark energy nor a big bang either.
Your next question should be how do we test this?
Well, Shu compared his model to the type 1a supernova data that started the whole dark energy hubbub and he said the data matches exactly.
A Physorg article I read said:
“it fits the redshift data of the observed supernovae quite well.”
Take away from that what you will.
This is a fascinating theory but one problem that Shu needs to resolve is the CMB itself. Right now he has no explanation for it so I’m curious to see what could possibly explain that away.
That in itself seems to be the main deal breaker for this theory. He won’t even get out of the gate if he can’t deal with that.
There’s tons of other problems too. What about nucleosynthesis and the observed abundances of elements in the universe that are consistent with the big bang?
Perhaps entropy is reversed in the contraction phases. That’s a big “perhaps” though.
It’s pleasing though to think of an unending universe. I’m not looking forward to its heat death.
A physicist friend of mine had some technical comments about this that I’d like to share:
” the speed of light isn’t really a conversion factor between space and time but rather spatial distance, and time distance (which are 2 very different things).”
“To accept that the speed of light changes with time throws out (at the very minimum) General Relativity, Special Relativity and Modern Electrodynamics – all heavily developed and tested fields of Physics that have stood up to the test of time.”
Thanks Adrian you geek!