http://www.smbc-comics.com/comic/best-3
Alt text
The only possible problem is if being crushed in a universe-ending sea of flesh would make it no longer be the best day ever.
http://www.smbc-comics.com/comic/best-3
The only possible problem is if being crushed in a universe-ending sea of flesh would make it no longer be the best day ever.
this is making the key assumption that the number of people that exist in the future is the same as the number of people that lived up until now, which seems unlikely. A bigger issue Id think is that if the universe ends (or really just the world, the universe is overkill), then all those time travelers from the future never can exist to do this in the first place, making this a classic time paradox.
I think it still works. If you increase the number of humans by 6 orders of magnitude, it still seems unlikely to form a black hole big enough to be an issue
Humans? How arrogant of you (<3) to assume that only humans exist and only they have access to time travel.
Add aliens (and artificial lifeforms) to the mix and watch the universe implode!
Plus the mass of time travel devices.