The planet Mercury may be hot, but it appears to be cooling down. ... Since planets cool from the outside in, the crusts are already compressed and compact by the time the interior cools.

As the closest planet to the Sun, Mercury is exposed to the star's enormous gravitational field. And it's really stressful.

Mercury is the closest planet to the sun and the smallest planet in our solar system.With a diameter of about 3,032 miles (4,880 kilometers), Mercury is less than half the size of Earth, which is ...

“It puts Mercury very close to Earth in terms of very slow cooling that allows the outside to remain cool and the inside hot.” Mercury is a tough little planet to study.

Set your alarms early as Mercury, which is the fifth planet to join the group, is set to rise just before 6:50 a.m. on Wednesday. Our sunrise is at 7:31 Wednesday morning.

Mercury is the solar system’s Greenland. We know it’s there, we’ve heard some interesting stuff about it, but we just don’t give it a whole lot of thought — and that has long included ...

The smallest planet in the solar system is growing smaller. The cooling of Mercury’s core has reduced its diameter by about a mile over recorded history, according to the journal Science. A J… ...

Astronomers have found a new planet that's mostly made of iron NASA's TESS telescope finds a small, iron-rich planet which could help explain the origins of Mercury, the innermost planet in our ...