Sean Raymond

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 dominant […]

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 […]

What would our solar system look like if an alien were to spot it from another planet, orbiting a distant star? How improbable would it appear? For the first time in human history, thanks to advances in exoplanet hunting, we can now answer that question. We can even put numbers on it. If that alien […]

There is an unsolved problem I want to tell you about: The case of the missing Trojans. You might be thinking of the mythical horse with soldiers hidden inside. Or maybe you’re thinking of a sports team. Or a type of computer virus, or, let’s be honest, of the condoms. (Note that I said, “Case […]

Ever notice how pretty much all superhero movies are origins stories? Everyone wants to know how Batman and Wolverine and the Hulk became who they are. But there aren’t too many superhero-in-old-age stories out there, with balding, hunchbacked super-oldsters hobbling around assisted-living homes.The same goes for the Solar System. The question of how the Solar […]

Imagine that two very similar-looking neighbors undergo a genetic test. The exam shows that the pair’s genetic fingerprints are virtually identical. They feel a flash of shock and excitement. What does this mean? Could they be long-lost twins, separated in a hospital mixup?The Earth and Moon share a similar issue, one that poses a major […]

Jupiter is famous for its Great Red Spot, but the stormy planet may also be responsible for keeping the inner solar system calm.NASA/JPL You are special, just like your parents used to tell you. You are a rare flower, a unique snowflake. Just like everyone else.How about our solar system? Is it special? Earth used […]

Imagine a habitable planet orbiting a distant star. You’re probably picturing a variation of Earth. Maybe it’s a little cloudier, or covered in oceans. Maybe the mountains are a little higher. Maybe the trees are red instead of green. Maybe there are scantily clad natives … OK, let’s stop there.That image may very well be […]