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If you're developing an alien spacecraft to come visit the earth for some reason, since no one knows we exist beyond 100 light years from now.

So let's say by accident, they stumble upon us. They built a spacecraft that spends 99.999% of its time traveling through space.

But they develop something like a flying saucer, which is meant to be aerodynamic,

in the atmosphere of the Earth, which they didn't even know was there until they get here.

But why would they design a spacecraft a flying saucer, if you wish,

which is not the most effective way of traveling through interstellar space. The laws of physics tell us here, here's the thing.

Lawrence Krauss, welcome to New Jersey, sir.

It's so great. I think this is the first time I've been in Hoboken.

Really?

I was trying to remember if I've been Hoboken before.

I don't think so. This is my first.

It'll be memorable.

Didn't you grow up right over here? I was born right over there, but I moved out when I was three months old. I said, I don't want to live here anymore. You made that decision. I grew up in Canada. You grew up in Canada. In Toronto, yeah. So you're a true Canadian. I'm at, well, I'm a sort of semi-true Canadian. Yeah, I actually became Canadian, although when my parents became Canadian, I thought I'd lost my American citizenship. In fact, when I came back to graduate school at MIT, I was on a visa. Really? And, yeah, I was on a visa all the time, and then I got my first job at Harvard, and I tried to get permanent residency, and the Harvard lawyer said, we think you're a citizen. Yeah. Is that possible to lose it? Well, at that time, you apparently could. You see, my parents became Canadian. They lost their American citizenship, because at the time you had to renounce your citizenship in order to become citizen of another country. But because I was a kid, I didn't suffer for the sins of my parents.

And I, anyway, so I, I, the Harvard lawyer said, you know, you can find out by applying for a passport, which I did.

Got my passport, tore up my visa.

And anyway, so I'm a citizen of both, I'm a citizen of both countries countries but yeah you don't have a canadian accent i don't detect that's it well every now and then if i say about or something i guess i do but but then you know i don't know what my accent is but some people say they can hear the canadian accent and i think Canadians hear an american accent but i lived in the u.s longer than canada i grew up in canada but then i moved in my 20s to go to graduate school. But I lived in the U.S. longer than Canada. I grew up in Canada,

but then I moved in my 20s to go to graduate school, and then I lived in the U.S. continuously until two

years ago, I moved back to Canada. When you were a kid, when did you first get bit by the science

bug and the meaning of it all? Well, you know, I've tried to think of that a lot because my uh my mother

wanted me to be a doctor and my brother to be a lawyer of course and and uh so she told me doctors

were scientists so i think from a little time i was a little kid since i thought i wanted to be a doctor

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