Naked Science Forum
Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: thedoc on 14/08/2012 18:30:02
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Jonno R asked the Naked Scientists:
Hi Dr. Chris, John here from London.
How accurate are mathematical projections about the distant future of the universe? Is it really going to happen or is it all just fun with maths?
Originally I had a few questions about the heat death of the universe. How big would the universe be at the point just before everything stops? And would the question of size be relevant at the point just after? And if the dead universe is just energy with no time, mass or dimension, is that not a singularity?
The thing is that as we don't understand dark matter and energy, is it even worth asking these sort of questions? Surely mathematical projections into the past and future become more inaccurate the further you go If the model isn't complete.
Is it unfair to say that scientists should stop frightening us with projections about the unobservable until they fully understand the observable? I'm only 50 and so far I've been told that I would float in circles forever. Then it was decided that I was going to be crunched up small. Now suddenly I'm going to fly apart into little bits.
Great podcast (http://www.thenakedscientists.com/HTML/podcasts/), thanks.
John Raab.
What do you think?
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what happens to "you" depends on what you are, where you are, and how long you wait.
All things must pass and human life is very short.
Barring catastrophes like a large meteor strike or a very nearby supernova or a major outburst from the black hole at the centre of our galaxy and a lot of other unlikely possibilities here is a scenario for the future.
Life on earth has had to survive vast changes in climatic conditions from extreme cold to extreme heat and has done so for at least 3 to 4 thousand million years and the earth will continue to orbit the sun for a similar length of time but the gradual increase in heat from the sun as it ages will probably destroy life within the next thousand million years when the earth will become a runaway greenhouse planet like Venus but that is still several times the period that complex life has existed on this planet. The gradually expanding sun in its red giant phase will probably swallow the earth before it sheds it outer layers and collapses back into a white dwarf which can last for trillions of years.
Star and galaxy formation will eventually cease as material is used up and eventually very slow orbit decay will cause things to fall into black holes and get squashed over many quarillions of years and large black holes will evaporate into low energy electromagnetic radiation over periods so vast it is not possible easy to describe them this is the eventual heat death.
The possibility that "dark energy" will make this cool down a bit quicker does not have a great deal of effect on the final result we do not have a good enough grasp on it origins to have a good model but the results observed are very small close to the limits of detectability and still a small proportion of the normal expansion of the universe anyway.
This is the final fate of the changing collections of atoms that currently make up "you" They will first be fried and then as you say go round in circles for a long time then eventually be squashed small and ripped apart before finally slowly being radiated into total emptiness and nothing.
Rest assured that barring other sorts of catastrophes your existence as a human being will be terminated within one hundred years or so and you will experience none of this.
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Thanks Soul Surfer, you really know how to make a long story short. Is your answer based on theory or observation?
What I'm really asking is about the certainty of your answer. Is this according to current knowledge but open to new discoveries? or is this literally the final answer?
Did you all get your sums right this time? or could there be a time when the universe starts to misbehave and you have to invent another dark thingy to explain it? :)
Jonno.