Timeline for What will happen to life on Earth when the Andromeda and Milky Way galaxies collide?
Current License: CC BY-SA 3.0
11 events
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| Mar 11, 2014 at 8:47 | comment | added | usethedeathstar | @user130144 the problem with those numbers is that masses of galaxies and distances and so on, the errorbars are astronomical (pun intended). It is quite difficult for some things to accurately say how fast it will happen since the distancescales and timescales on these things are so massive that they are hard to determine exact numbers for certain quantities. That being said though, the numbers you give are "the best estimate" that we can do with current technology, so i am not saying it is wrong, just that some of these numbers can be quite different ten years from now (better instruments). | |
| Mar 7, 2014 at 23:58 | comment | added | user130144 | Stackexchange makes it difficult to link to anything. For things like the masses and dimensions of stars and galaxies, Wikipedia is the most quickly available reference. Calculators and NIST have fundamental constants such as $\sigma$, the Stefan-Boltzmann constant (although extra digits do no good here). UNL has a helpful simulation for the evolution of Sol which predicts its future luminosity. It isn't clear to me how they determine when Earth will leave the habitable zone. With less carbon, Venus might still be habitable. | |
| Mar 7, 2014 at 7:15 | comment | added | usethedeathstar | one question: what reference do you have for all the numbers you use in this answer? | |
| Mar 6, 2014 at 10:25 | comment | added | user130144 | Thanks for the links. I have thought about changing my ID... but this is a very unusual randomly chosen number. | |
| Mar 6, 2014 at 9:12 | comment | added | user130144 | Earth seems to be still habitable (but unpleasant) four billion years from now. When Sol runs out of hydrogen to fuse, several hundred million years later, it is likely to expand much more rapidly and either melt or vaporize the entire planet. A greater immediate threat is an asteroid or a light-year-wide beam of gamma rays from something like WR-104. There are no plans currently for escaping those; if it becomes possible, making a destination habitable should be easier than leaving Sol. | |
| Mar 6, 2014 at 8:37 | comment | added | AmitG | In only worst case scenarion, 1> will life exist? 2> If we are about to collide in next 4 billion year then how long before we should take action for inter-stellar voyage? 3> Are scientists working on such projects for inter-stellar voyage? 4>Will we be able to get the portal like earth ? | |
| Mar 5, 2014 at 22:47 | history | edited | user130144 | CC BY-SA 3.0 |
might as well use the most recent value of σ
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| Mar 5, 2014 at 22:39 | history | edited | user130144 | CC BY-SA 3.0 |
20% of a solar radius is 2‰ of an AU; Earth seems to really be still habitable in 4e9 years, from Sol's perspective
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| Mar 5, 2014 at 21:10 | history | edited | user130144 | CC BY-SA 3.0 |
missing factor of 2 is worse for stars but not Earth
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| Mar 5, 2014 at 20:54 | history | edited | user130144 | CC BY-SA 3.0 |
600 _thousand_
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| Mar 5, 2014 at 8:59 | history | answered | user130144 | CC BY-SA 3.0 |