Jack C. Davis Observatory
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Jack C. Davis Observatory
Planetary Walkway: Earth
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Building a Future with Vision
On the Third Rock from the Sun
"Earth first, we'll develop the rest of the planets later."
Builders Association of Western Nevada
Earth, our home planet, is the only planet in the solar system known to harbor life - life that is incredibly diverse.
Earth is the planet we understand better than all the rest and the rate of new discoveries about our home planet is amazing, surprising, and satisfying from a human perspective. NASA's Apollo 8 mission to the Moon took the first Earth rise picture on the Moon's horizon that depicted a "pale blue dot" our Earth alone in space. The Earth experiences a slight greenhouse effect which allows its surface temperature to be approximately 288 K (15.0° C or 59.0°F). Earth would be at a frigid -1.0° C without the moderating effects of the atmosphere. Earth has a Moon that modern theory suggest was formed by a collision of a Venus sized planet when the Earth was very young.
Earth is 1 A. U. (astronomical unit) equal to 1,496,000,000 km or approximately 93 million miles form the Sun. The Earth supports a robust amount of life most of which is not human, but vast assemblages of microscopic life. Life forms have adapted to Earth's extreme environmental conditions in the crust of the Earth under the oceans, its driest deserts, and even in hot water vents of active geysers.
The Earth is the only planet not named for a Roman god. Many cultures have an assortment of names for the Earth like Jeegoo (Korean), Terra (French), and Gaia (Greek) to name a few. The Earth is the densest planet in the Solar System and is the largest terrestrial planet. Earth rotates on its inclined axis in 24 hours and it takes 365 days for a complete orbit around the Sun with approximately 71% of the Earth's surface is covered by water.
Quick Facts
- Mean Distance from Sun: 149,597,890 kilometers (1 astronomical unit)
- Orbital Period: 365.26 days
- Rotational Period: 23 hours 56 minutes
| Earth Images | ||
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| This color image of the Earth was obtained by Galileo when the spacecraft was about 1.3 million miles from the planet. | ||