PeterDonis's latest activity

No, this is not a requirement. For example, you're perfectly justified in saying you're stationary as you type your posts here. But you...

Yes. Yes. Both of these functions will be square integrable functions of one variable, so they are both elements of Hilbert spaces...

This is not correct. Wave functions are elements of a Hilbert space--for example, the wave function of a single spinless particle moving...

That's true, but I think the technological aspects of those challenges are already well within our capability. The aspects we still have...

There is no such thing. Speed is always a relative concept and you can always consider yourself "at rest" or "moving". As physicists...

On a time scale of thousands or millions of years, those things are highly changeable. To the extent they're constraints on that kind of...

In half a century or so. That's an extremely short time on the scale of human history. Sure, but the time frames you're giving for when...

On time scales of thousands or millions of years, the engineering realities can change drastically. The engineering realities of Stone...

I think you underestimate the difference in scale and technical feasibility between living on a single planet and finding and moving to...

Hindsight is always 20/20. Those that set out didn't have that benefit. They still went. Ask the Roanoke settlers if they were...

Tell that to any of the babies who died en route. Does the ethics matter if, in the end, they dIed anyway becuae of their parents'...

Why would you need any more than a smidge of gravity? Say, 20%? Just enough to make sure things don't float around in the corridors...

(1) Generation ships need not be "horribly inhumane". A space habitat hundreds of meters in diameter could be quite a pleasant place to...

Yes. Many of which do not apply to this topic of discussion. This is about exo-biology. Competent scientists are not looking at...

Who are you to say what has to do with definitions of life? There hundreds of them. One of the most prominent ones is the NASA...