Humans have existed only for the last 0.001 percent of cosmic time. All of which says that - unless the Homo sapiens brain is the one-and-only instance of cogitating machinery - nearly all the intelligence that's out there is beyond our level. And that intelligence is more than just a little bit beyond.

— Seth Shostak

If you could drive straight down, into a tunnel bored through the crust of the planet, you'd hit this molten mess in about an hour. It's called the asthenosphere - a sluggish sea, several hundred miles thick, on which floats the Earth's cool epidermis - the so-called tectonic plates.

— Seth Shostak

If you still believe that aliens would travel hundreds of light years to carve temporary graffiti in our wheat, then your imagination is one of the seven wonders of the world, and should be bronzed.

— Seth Shostak

In archaeology, context is the basis of many discoveries that are imputed to the deliberate workings of intelligence. If I find a rock chipped in such a way as to give it a sharp edge, and the discovery is made in a cave, I am seduced into ascribing this to tool use by distant, fetid and furry ancestors.

— Seth Shostak

In the four years since its launch, Kepler has chalked up 122 new and confirmed planets. It's also caught the scent of nearly three thousand additional objects, of which probably 80 percent or more will turn out to be other-worldly orbs.

— Seth Shostak

Is E.T. out there? Well, I work at the SETI Institute. That's almost my name. SETI: Search for Extraterrestrial Intelligence. In other words, I look for aliens, and when I tell people that at a cocktail party, they usually look at me with a mildly incredulous look on their face. I try to keep my own face somewhat dispassionate.

— Seth Shostak

It bears mentioning that the Milky Way is only one of 150 billion galaxies visible to our telescopes - and each of these will have its own complement of planets.

— Seth Shostak

I think there's a lot of intelligence out there, but that's just my guess. Question is: Are they peaceable or hostile? You could say that the peaceable ones are just going to stay at home and play with their Nintendo's, so if you do meet any of them, they might be hostile.

— Seth Shostak

It seems obvious that if a species has the brainpower for speech, along with the sort of appendages that can manipulate a pair of pliers, it will eventually blunder into science, technology, and radio.

— Seth Shostak

It's hardly a secret that I'm skeptical of declarations that the aliens are out and about on our planet. Still, I try to answer every one of these mails and phone calls because, after all, it's not a violation of physics to travel from one-star system to another.

— Seth Shostak