"If we are correct, this is the first time we are seeing a planet forming inside its natal environment."
How do planets form? The most commonly accepted explanation is the nebular hypothesis: Dust grains circling around a parent star collide, the hypothesis goes, and develop into larger objects through a process of accretion. But one reason the hypothesis remains a hypothesis is that it's incredibly hard to observe the phenomena it's trying to explain: We haven't actually been able to witness the birth of another planet from our perch here on this one. We take the evidence we have -- the stuff we can observe -- and reverse-engineer.
Now, though, researchers claim to have spotted a planet in the first pangs of its birth, and they've shared their findings in a paper [pdf] published in the journal Astrophysical Letters. Relying on pictures captured by a high-resolution infrared camera -- which was linked to the European Southern Observatory's Very Large Telescope in Chile -- the team observed what seems to be a planet in the midst of a disk of gas and dust that surrounds its central star, HD 100546 -- a star located in the Milky Way, 335 light years away from Earth. The protoplanet is about as massive as Jupiter, and, like Jupiter, a gas giant.