Gravity on Earth Gravity is very important to us. We could not live on Earth without it. The sun's gravity keeps Earth in orbit around it, keeping us at a comfortable distance to enjoy the sun's light and warmth. It holds down our atmosphere and the air we need to breathe. Gravity is what holds our world together. However, gravity isn’t the same everywhere on Earth. Gravity is slightly. Planets that orbit closer to the Sun than Earth have shorter years than Earth. Planets that orbit farther from the Sun than Earth have longer years than Earth. A planet orbiting close to its star has a shorter year than a planet orbiting farther from its star. Credit: NASA/JPL-Caltech This happens for two main reasons. All About the Moon Quick Facts: Earth has just one moon – a rocky, cratered place, roughly a quarter the size of Earth and an average of 238,855 miles away. The Moon can be seen with the naked eye most nights as it traces its 27-day orbit around our planet. Average distance? Why mention the average distance? Well, the Moon is not always the same distance away from Earth. The orbit is not a perfect circle. When the Moon is the farthest away, it’s 252,088 miles away. That’s almost 32 Earths. When it's closest, the Moon is 225,623 miles away. That’s between 28 and 29 Earths. So far apart! Earth's lopsided orbit Earth's perihelion (point closest to Sun) = 91,400,000 miles from Sun Earth's aphelion (point farthest from Sun) = 94,500,000 miles from Sun While that is a difference of over 3 million miles, relative to the entire distance, it isn’t much. The closest known nebula to Earth is called the Helix Nebula. It is the remnant of a dying star—possibly one like the Sun. It is approximately 700 light-years away from Earth. That means even if you could travel at the speed of light, it would still take you 700 years to get there! Learn more about what happens when the moon passes between Earth and the sun! explore How Is the Sun Completely Blocked. It all has to do with the distance between Earth and the sun and Earth and the moon. explore Asteroid or Meteor: What's the. Learn more about asteroids, meteors, meteoroids, meteorites, and comets! explore What Is an. Learn about NASA space and Earth science with our educational games for kids It all has to do with the distance between Earth and the sun and Earth and the moon. explore Make Handprint Art Using. We can't see the sun's ultraviolet light with our eyes, but with this simple activity we can observe the effects of UV light. do How Does Our Sun Compare With. The Sun is actually a pretty average star! explore Make Sunspot. Lasers have also been used in instruments that map the surfaces of planets, moons, and asteroids. Scientists have even measured the distance between the moon and Earth using lasers! By measuring the amount of time it takes for a laser beam to travel to the moon and back, astronomers can tell exactly how far away it is!.