[mrybczyn]

We just have to get creative, or discover some new physics :-)

In addition to the ark-ship colony, or the cryosleep slow ship:

1. Assuming it's a stream of robotic probes doing flybys, without decelerating, we have the Breakthrough Starshot approach. Maybe there's a way to use the target system's sun for solar sail braking? Send smart enough robots that have agency, that can do the exploring for us.

2. For human travel - it could just be a bunch of frozen embryos with a robotic nursemaid, accelerated via external propulsion and decelerated via nukes / high-g aerobraking... (Raised by Wolves had a cool introduction like this in the first episode - then went quickly downhill)

3. ...

[jmyeet]

"we need new physics" basically means "I hope this isn't true". I get it. I think many of us would like to wander the stars in a reasonable timeframe but there's simply no evidence the Universe works this way.

As for cryosleep, this curently seems unlikely but not impossible. For one thing, the decay of radioactive elements in your body (primarily Carbon-14) would give you about a lethal dose of radiation after about a century. Some organisms have natural antifreeze and other means of surviving low temperatures. We do not. Freezing water tears our cells to shreds.

Cryobabies and artifical wombs are another vector. This is nontrivial too but also, woould you trust the automation? Some AI might have to raise humans hundreds or thousands of years in the future without any context of what's happened in that time. We might be able to communicate with such a ship and update it but should it trust such updates?

You're also creating a whole bunch of people who haven't consented to never see Earth. Generation ships have this problem too to some degree. That has questionable ethics.

As for using the target star to decelerate, that's entirely possible. It's just a solar sail. And that might be the only way we could do interstellar travel anyway because of the reaction mass problem. But solar sails can only accelerate so fast. Travel too fast and you might not have time to decelerate as well. So you're still looking at hundreds of years most likely.

It really seems like we need radical life extension while maintaining quality of life to make these time frames reasonable (relatively). That actually does seem doable.

[largbae]

I agree with most of this, but the ethics question intrigues me: did any human ever have a chance to consent to the circumstances they were born into?