/sci/ - Science & Math

>>12413449
>>12414634
The physics is pretty clear, you can travel to other side of the galaxy and back easily in a single human lifespan. SFG is full of posci retards who don't understand time dilation.
At 1G constant acceleration you can get to relativistic speeds in about a year, time dramatically slows for the occupants of the craft. Apart from the propulsion source there's nothing stopping this.

>>12073772

>>10970703
With relativity it's more of an energy density problem than a "speed limit" problem.

>>10870412
>Unless some genius can prove Einstein wrong we are done.
What is time dilation?

>>9484377
>>9484500
It's about the reference frame. If a ship goes from Earth to something 200,000 ly away at a constant speed of 0.5c, indeed 400,000 years will have passed on earth when the ship reaches it's destination. But because of time dilation at speeds close to c, much less than 400,000 years will have passed on the ship.

Furthermore, in school exercises, spaceships usually travel at a constant speed. But it makes more sense to have them travel at a constant acceleration (if you are just bound by kinematics, not by engineering). Us humans are somewhat acceleration limited, we can't be at any destination arbitrarily fast because if that requires accelerations of 100 g, we would be a pancake. Because acceleration is the only theoretical limit for us humans to travel, there is a commonly theorized spaceship that accelerates at 1 g. This means we feel the same "gravity" as we feel on earth during the travel. Pic related is really great and worth a closer look. It depicts how long round trips to various destinations would take in the reference frame of the space ship and in that of earth. It's sad that this is not common knowledge and that there is so much pessimism about human space travel. From a pure kinematic view, a human can easily travel to all galaxies we know within a lifetime. How to engineer a ship that stores so much energy or somehow gets it from somewhere else is a different question of course, but there are no physical laws that say it's impossible to build it.

https://en.wikipedia.org/wiki/Space_travel_using_constant_acceleration

>>8500023
If you could accelerate at 1g continuously you can visit the edge of the universe in a surprisingly short amount of subjective time.