Exoplanets can come in a variety of sizes and masses ... loss of thick planetary atmospheres all conspires to preferentially create two populations of planets: the super-Earths that are rocky ...

All seven planets are rocky worlds, ranging from about the size of Mars to a little larger than Earth. Three or four of them reside within their star's habitable zone, meaning they orbit at the ...

Smaller worlds on the other side of the radius valley, with radii of 1.4 times that of Earth or less, would have lost all their hydrogen ... of sub-Neptune-size planets, which are clearly a ...

Today, it’s believed that Jupiter and Saturn, the largest planets, were the first to fully form, both within a few million ...

Many of these worlds are closer in size to the largest planets in our solar system ... are much larger than what Hubble is capable of, all while providing the same level of intricate detail.

All planets are born with a certain amount of heat ... While Mars started out similar to Venus and Earth, its smaller size meant that its gravity wasn’t strong enough to hold onto the small ...

All planets are born with a certain amount of heat ... While Mars started out similar to Venus and Earth, its smaller size meant that its gravity wasn't strong enough to hold onto the small ...