Earth Day is observed on Monday, April 22. To celebrate, we're ranking our five favorite "Earth Facts" as told by LiveScience.com:
Messenger editor Tyler Buchanan
1. The planet has a waistline (circumference of 24,901 miles)
2. Earth's moon has moonquakes
3. The hottest spot recorded on Earth is in Libya
4. The Earth may have once had a second moon, researchers theorize
5. Each liter of seawater contains, on average, about 13 billionths of one gram of gold.
Staff journalist Heather Willard
1. The planets rocks are recycled through the rock cycle.
2. Gravity on Earth is uneven.
3. Mount Everest may be known as the tallest mountain, but Mauna Kea when measured from true base to summit takes the prize.
4. Coral reefs are the largest living structure on the planet.
5. There have been several supercontinents in the Earth's history.
Staff journalist Sydney Dawes
1. The Earth isn't just spinning: It's also moving around the sun at 67,000 miles (107,826 km) per hour.
2. Because our globe isn't a perfect sphere, its mass is distributed unevenly. And uneven mass means slightly uneven gravity.
3. Over the past 20 million years, our planet has settled into a pattern of a pole reversal about every 200,000 to 300,000 years; as of 2012, however, it has been more than twice that long since the last reversal.
4. The ground you're walking on is recycled. Earth's rock cycle transforms igneous rocks to sedimentary rocks to metamorphic rocks and back again.
5. Earth may once have had two moons.