About the aliens visiting the earth....Yes, they have been here, but..........

[PoindexterOglethorpe]

32. It means Faster Than Light. And I'm sorry, I should know better

than to post an abbreviation without explaining it the first time.

In science fiction, there are often references to FTL drives, meaning engines (or drives) that allow a ship to travel faster than the speed of light.

In one of the Jack McDevitt series (I'm sorry, I forget which one) originally the FTL drive, while better than travelling at even 99% c (and here c means the speed of light, as in E = mc2, Einstein's famous equation) still the trips often take a month or more to get from one place to another. Then McDevitt invented a better FTL drive, and so ships weren't stuck in hyperspace (I think that's what he calls it) for more than a few days at a time. What's nice about science fiction is that you can happily make up pretty much whatever you want to.

As for E = mc2, that rather famously says energy and matter are two different versions of the same thing. The Wikipedia article on special relativity may be helpful here.

As you might guess from the several references to My Son the Astronomer, I rely on that son for lots and lots of stuff. I joke that I could just give out his phone number, you could text him, claiming to be a friend of his mother's and query, "Is Ask the Astronomer on Duty?" I often send him such a text, and if the astronomer is available, he'll call me back. In reality, I wouldn't abuse his good nature by randomly giving out his phone number, but I learn new things from him all the time.