IWantAHoverbike t1_irgwz6w wrote on October 8, 2022 at 1:11 AM

What would it cost to make an absolutely enormous birthday cake, put this photo inside it, and send it off on a solar escape trajectory to arrive there in a few billion years?

danielravennest t1_irj6qtb wrote on October 8, 2022 at 5:00 PM

We don't know, because of the arrival paradox. If technology is improving, a later mission can travel faster and arrive sooner. So there is no reason to attempt a trip until (1) the trip time is short enough that you won't be overtaken by a faster mission, or (2) technology has reached some limit and isn't improving.

For interstellar trips, neither condition is met right now. For solar system trips, we are working on better propulsion such that any trip over 20 years that started today is likely to be overtaken.