MERCURY

Mercury is the planet closest to the Sun, and experiences scorching temperatures by day. But it has virtually no atmosphere to trap the heat, so is freezing at night. It is a rocky planet, just over a third the diameter of Earth. Its surface is covered with craters, which make it look similar to parts of the Moon. These craters were formed when the planet was bombarded with meteorites long ago.

Table 9. ESSENTIAL DATA

Diameter at equator4,880 km (3,032 miles)
Average distance from Sun57.9 million km (36 million miles)
Orbital period88 days
Rotation period58.7 days
Mass (Earth=1)0.06
Gravity (Earth=1)0.38
Average surface temperature167°C (332°F)
Number of moons0
MERCURY’S SURFACE

The craters that cover almost all of the surface of Mercury are generally shallower than those on the Moon. They vary in size from a few metres to hundreds of kilometres across. In between, there are relatively smooth lava-covered plains crossed by cliffs and ridges.

Copyright © 2007 Dorling Kindersley

highlights

8 Quick Tips for Curbing Your Family's Screen Time
Setting limits on screen time — and remembering to put down our own devices — is one of the biggest parenting challenges of our time. Use this guide to create healthy screen-time rules for your whole family.

Find Today's Newest & Best Children's Books!
Looking for newly released books for your child? Try our new Book Finder tool to search for new books by age, type, and theme, and create reading lists for kids!

10 Best Beach-Themed Crafts and Activities
Sand, seashells, and stones can provide hours of family fun. Check out the greatest beach-related activities and crafts for toddlers on up.

Registered for Kindergarten — Now What?
Try our award-winning Kindergarten Readiness app! This easy-to-use checklist comes with games and activities to help your child build essential skills for kindergarten. Download the Kindergarten Readiness app today!

stay connected

Sign up for our free email newsletters and receive the latest advice and information on all things parenting.

Enter your email address to sign up or manage your account.

Facebook icon Facebook icon Follow Us on Pinterest

editor’s picks