[Capitalism2003]

Even if it were possible to go the speed of light, the human body couldn't practically take it...It would take around 15 years accelerating with 3G's of force (which is a LOT for a constant pressure) to reach the speed of light...another 12 years to slow down...12 to speed up and 12 more to slow down on the way back...50 year minimum journey and no way to communicate with earth?..not practical...unless we find a way to freeze people and forget about them for a hundred years.

[Stefan Stackhouse]

Even if it were possible to go the speed of light, the human body couldn't practically take it...It would take around 15 years accelerating with 3G's of force (which is a LOT for a constant pressure) to reach the speed of light...another 12 years to slow down...12 to speed up and 12 more to slow down on the way back...50 year minimum journey and no way to communicate with earth?..not practical...unless we find a way to freeze people and forget about them for a hundred years.

Human interstellar voyages, if they ever happen at all, will not be two-way voyages of exploration, but rather one-way voyages of colonization. For exploration, robotics are definitely the way to go. As you explain, why would anyone want to spend their entire lives stuck inside a spaceship just so they could see another planet? The opportunities that go with colonization of new territory, however, will always be attractive to some people.

Since the trip will be one way, there also will be no need for the trip to be quick. Even if a habitable planet is found within about 10 - 20 l.y. or so, you will pretty much be talking about a voyage that will last at least one lifetime, maybe two. So we will be talking about a colonist setting off for a new home planet that they themselves may not live to see, and committing their children or grandchildren to this venture with no choice in the matter. Some interesting and difficult ethical questions there!

[boris]

"Even if it were possible to go the speed of light, the human body couldn't practically take it...It would take around 15 years accelerating with 3G's of force (which is a LOT for a constant pressure) to reach the speed of light...another 12 years to slow down...12 to speed up and 12 more to slow down on the way back...50 year minimum journey and no way to communicate with earth?..not practical...unless we find a way to freeze people and forget about them for a hundred years." Your math is wrong (unless you are including relativistic effects; I have not done that calculation). As I pointed out above, one "G" is 1.032 light years/year/year.

--Boris