Starship Asterisk*

I wonder how much sooner in the development of human knowledge we would have accepted a helio-centric view if the moon didn't always show the same face to the earth. I guess this is nearly impossible given the number of moons in our solar system that are tidally locked and the time frame over which ...

The news occasionally runs stories about meteorites from Mars carrying gasses or amino acids or even primitive cellular life to other planets or other panspermia-type scenarios. I can't help being skeptical of impact-driven scenarios on other worlds where fragments that survived becoming completely ...

Maybe this has already been asked, but why do we know that whatever is sublimating on Mars is water ice? Couldn't it also be solid CO2? (which on earth is also stark white)