Sean Raymond

How advanced civilizations could leave us a message of their presence.

New research hints at what makes Earth’s moon special.

Could a comet, not an asteroid, have killed the dinosaurs?

About half of all stars seem to have “super-Earth” planets on orbits closer to their stars than Mercury is to the Sun, but we don’t.Illustration by Vadim Sadovski / Shutterstock Is Earth unique? Once a grand philosophical question, it has, over the past two decades, become, with the discovery of thousands of planets around other […]

Artist’s conception of a hot Eyeball planet. The permanent day side is sun-baked and dry. The permanent night side is covered with ice. In between lies a thin habitat: the ring of life.Illustration by Beau.TheConsortium Imagine a habitable planet orbiting a distant star. You’re probably picturing a variation of Earth. Maybe it’s a little cloudier, […]

‘Oumuamua may be a piece of a torn-apart comet, gravitationally launched into interstellar space, that roamed the galaxy before dropping on our doorstep.ESO / M. Kornmesser / Wikicommons Our solar system’s first houseguest—at least, the first one we have seen in our midst—is a strange one. Scientists have taken to calling it ‘Oumuamua (pronounced “Oh-MOO-ah-MOO-ah”), […]

This system is completely stable—I double-checked with computer simulations. But nature would have a tough time forming this system. If it exists, it could only have been built by a super-advanced civilization.Image by Sean Raymond / planetplanet.net When Frank Drake was a boy, growing up in 1930s Chicago, his parents, observant Baptists, enrolled him in […]

This system is completely stable—I double-checked with computer simulations. But nature would have a tough time forming this system. If it exists, it could only have been built by a super-advanced civilization.Image by Sean Raymond / planetplanet.net When Frank Drake was a boy, growing up in 1930s Chicago, his parents, observant Baptists, enrolled him in […]

Let There Be Moon: Artist’s rendition of the moon-forming impact between Earth and Theia, a proto-planet.Hagai Perets Some marriages are arranged. Some are for love, others for convenience. Some happen as the result of a sextillion-ton collision in space. The Earth and the moon, for example. Over the past twenty years there has been one […]

A couple years ago, I was part of the team that discovered the first Earth-sized planet, Kepler-186f, rotating comfortably in its star’s “habitable zone,” where water can be liquid. Its sun, Kepler 186, is faint and far away from us—and a little colder than we’d like if we were to settle there—but it does have […]