Crosswords16 mins ago
gravity vs expansion
As the universe expands and the galaxies move further and further apart, will the galaxies themselves increase in size as the space between the stars also expands . In the long run will the expansion overcome gravity until all the galaxies simply disappear ?
Answers
1 to 8 of 8
Best Answer
No best answer has yet been selected by claymore. Once a best answer has been selected, it will be shown here.
For more on marking an answer as the "Best Answer", please visit our FAQ.
I think Teddio has expressed the current majority view.......however.... on Sky at Night this week Patrick Moore, having elicited just this view from three experts in the studio, pointed out that some 50 years ago on the same programme he had stated 6 "known facts" about the planet Venus, every one of which turned out not to be true. At the risk of being as wrong as he was may I say
1 It may be likely that the universe wll continue to expand but we can't be absolutely sure
2 Whether it will or not, will have no effect on the day to day lives of anyone currently alive or for the next 10,000 years. So let's just say that something which didn't trouble the Ancient Egyptians needn't trouble the modern ones either.
1 It may be likely that the universe wll continue to expand but we can't be absolutely sure
2 Whether it will or not, will have no effect on the day to day lives of anyone currently alive or for the next 10,000 years. So let's just say that something which didn't trouble the Ancient Egyptians needn't trouble the modern ones either.
The galaxies which are very far apart will continue to move away from each other at an accelerating pace.
In local galaxy groups gravity will overcome the expansion and thus they will merge. As we know the milky way and the Andromeda will combine to form a single super-galaxy.
Over short distances (like within galaxies) gravity will keep the dark energy expansion in check.
Thus after a very long time By then the sun will have shrunk to a white dwarf, giving little light and even less heat to whatever is left of Earth, and entered a long, lingering death that could last 100 trillion years�or a thousand times longer than the cosmos has existed to date. The same will happen to most other stars, although a few will end their lives as blazing supernovas. Finally, though, all that will be left in the cosmos will be black holes, the burnt-out cinders of stars and the dead husks of planets. The universe will be cold and black with dark galaxies spread over trillions of light years.
In local galaxy groups gravity will overcome the expansion and thus they will merge. As we know the milky way and the Andromeda will combine to form a single super-galaxy.
Over short distances (like within galaxies) gravity will keep the dark energy expansion in check.
Thus after a very long time By then the sun will have shrunk to a white dwarf, giving little light and even less heat to whatever is left of Earth, and entered a long, lingering death that could last 100 trillion years�or a thousand times longer than the cosmos has existed to date. The same will happen to most other stars, although a few will end their lives as blazing supernovas. Finally, though, all that will be left in the cosmos will be black holes, the burnt-out cinders of stars and the dead husks of planets. The universe will be cold and black with dark galaxies spread over trillions of light years.
You are speaking about a theory which is called the Big Rip which I read about only very recently.
Big Rip ( from wikipedia):
The density of dark energy increases with time, causing the rate of acceleration to increase, leading to a steady increase in the Hubble constant. As a result, all material objects in the universe, starting with galaxies and eventually (in a finite time) all life forms, no matter how small, will disintegrate into unbound elementary particles and radiation, ripped apart by the phantom energy force and shooting apart from each other. The end state of the universe is a singularity, as the dark energy density and expansion rate becomes infinite.
ps:I doubt its credibility as I doubt anything which comes from wikipedia though the references may be useful.
Big Rip ( from wikipedia):
The density of dark energy increases with time, causing the rate of acceleration to increase, leading to a steady increase in the Hubble constant. As a result, all material objects in the universe, starting with galaxies and eventually (in a finite time) all life forms, no matter how small, will disintegrate into unbound elementary particles and radiation, ripped apart by the phantom energy force and shooting apart from each other. The end state of the universe is a singularity, as the dark energy density and expansion rate becomes infinite.
ps:I doubt its credibility as I doubt anything which comes from wikipedia though the references may be useful.
1 to 8 of 8
