Frost Line
Seeing the Moment Planets Start to Form
Nature makes few duplicates, and planets are as distinct from one another as snowflakes are. But planets all start out…
A New Place to Search for Habitable Planets: “The Soot Line.”
The habitable zone is the region around a star where planets can maintain liquid water on their surface. It's axiomatic…
Ceres Probably Formed Farther out in the Solar System and Migrated Inward
When Sicilian astronomer Giuseppe Piazzi spotted Ceres in 1801, he thought it was a planet. Astronomers didn't know about asteroids…
Organic Matter Could Have Delivered Earth’s Water
The origin of Earth's water is a big piece of the puzzle in Earth's history. Did it come from comets…
Why Doesn’t Earth Have Rings?
You'd think Saturn has all the luck, with its awesome rings. But it turns out, living on a planet with…
What is the Coldest Planet of Our Solar System?
Neptune, being the farthest planet from the Sun (sorry Pluto!) is now recognized as also being the coldest body in…
What is the Surface Temperature of Neptune?
Given its distance from the Sun, and the nature of its composition, Neptune is renowned for being the coldest planet…
Friendly Giants Have Cozy Habitable Zones Too
According to a recent study from the Carl Sagan Institute, aging red giant stars could still have habitable zones that…