Starship Asterisk*

Thanks to all for the replies. It is true you can ask anything (astronomy related) here, and some very smart minds will answer. I appreciate it.

Seems it also spurs debate, which is also a good thing.

I read the other day I could ask anything astronomy related so here goes. Regarding X-Rays, it was my understanding they are very short lived, and that's why they are (relatively) safe to use for medical purposes. However, if they do have short lives, how do they last long enough to reach us here so...