And in terms of elementary particles, he also means that after a long enough time, even protons will start to fall apart. At that point, the Universe is well and truly fucked.
There are plenty of people that don’t think, they too exist.
From my astronomy classes, my understanding is that isn’t true. Stars are like trees…as they die, new ones are born to replace them. The cycles of star life are so long and vast that it’s difficult for a human like us to really wrap our brains around the concept of a celestial body existing as long as it does in comparison to our meagre lifespans.
But technology is working on that mystery every day.
There’s a finite amount of hydrogen fuel available in the universe to create stars. After it’s all used up through the natural process of fusion, there’s no making any more of it. Supernovas can help ‘seed the Universe’, but you need the fundamental building blocks to make it happen. Eventually, that’s all going to run out.
Interesting. So is there a theory out there that ascribes to the possibility that billions and billions of years into the future, that due to current stars dying out and the universe’s continuous expansion that there won’t be enough matter left in close enough proximity to other matter for the gravitational collapse necessary to form proto-stars?
I had never thought of that.
What about supernovae explosions, then? They continue to occur with stars greater than 5 solar masses, and they expel the iron-rich components of matter into space that is required for new star formation upon their destruction…what about those?
How so? How can we possibly measure the amount of available hydrogen in the Universe?
In my mind, the Universe could very well be finite…finite beyond human comprehension, but finite still. Gravity is funny that way. I still haven’t seen a convincing theory against the expansion of the Universe to a “certain point” prior to it’s contraction.
Yes but new stars form by gravity pulling in fresh material to initiate the stellar process. As I understand it, the universe is not only expanding but evidently accelerating. Thus everything on a galactic scale at least is getting further away from everything else. So, over time any new material outside of a galactic realm will never be able to get close enough to other galaxies for gravity to do it’s work. And eventually the galaxies themselves will burn out as pointed out by the processes noted in the quote you cited.
But won’t galactic collisions and supernovae offset that occurence?
Again, over billions of years galaxies will apparently be moving away from each other faster due to expansion than gravity can compensate for. Over another 14 billion years or so if no new material from outside a galaxy is added these processes will begin to die down. Don’t forget that all nuclear processes left on their own decay so that to some extent galaxies start becoming colder. I’m not sure off hand how it is that galaxies die other than that their material might also expand outward making the critical mass needed to form new stars to be diminished.
On the other hand, I’m not sure how the cosmological constant affects dark matter as we don’t really know what dark matter is. I’m not sure why this would not keep galaxies going for a very long time as it is supposed to make up about 96% of all matter in the universe.
I have wondered if anyone has heard of any speculation that this cosmological constant which seems to be driving the expansion might have local effects. Has it been theorized that local space also expands though at an obviously slower rate?
But eventually you run out of hydrogen to burn. We’re talking really, really long time scales here – hundreds of trillions of years. We’re talking time scales that make the current age of the universe look like the blink of an eye.
It’s amazing to think that far ahead isn’t it?
The word vast is relative. The current spaces between particles might look just as vast to a sentient being whose whole civilization emerged, lived, prospered and died within an infinitesimal fraction of a femtosecond from the point in time we think of as the Big Bang.
I know that because of the amount of distance and time involved here that we’re REALLY quibbling, but do you have a cite for the theory that hydrogen will run out or be too dispersed to serve it’s current function in star formation in this Universal future of unreigned expansion?