In Star Wars: Episode V – The Empire Strikes Back , C-3PO tells Han Solo, “Sir, the possibility of successfully navigating an asteroid field is approximately 3,720 to one,” indicating that traveling through one of the galaxy’s asteroid clusters is potentially life-threatening. Many people have hung onto the belief that the asteroid belt is littered with these huge rocky objects just waiting to strike any spacecraft that passes by.
While it’s true that the universe contains millions of asteroids, some of which can be hundreds of miles wide, it’s unlikely that a ship would collide with any of them in the main asteroid belt. The chances of hitting one is actually less than 1 billion.
The asteroid belt, which is located between the orbits of Mars and Jupiter, contains rocky objects that range in size from a speck of dust to 590 miles across. It is unclear how many asteroids populate the belt, but it may consist of “billions — maybe even trillions — of asteroids,” according to Space.com . Fortunately, the asteroids are widely spread apart, allowing space agencies to safely explore the area.
In 1972, scientists launched the space probe Pioneer 10 into the asteroid belt. Images from flyby missions revealed that the rocky objects had miles of space between them, which would allow a spacecraft to harmlessly navigate that section of the solar system, which spans a whopping 140 million miles. Subsequent spaceships have also successfully entered and exited the region without colliding with an asteroid.
In 2006, NASA’s spacecraft New Horizons traveled through the asteroid belt on its way to Pluto. New Horizons principal investigator Alan Stern explained : “Fortunately, the asteroid belt is so huge that, despite its large population of small bodies, the chance of running into one is almost vanishingly small – far less than one in a billion. That means if you want to come close enough to an asteroid to make detailed studies of it, you have to aim for one.”
Astronomers have calculated the distance between asteroids and estimate it is about 600,000 miles. To put that in perspective, the distance between the earth and the moon is 238,855 miles.
Most asteroids are made of stone, metal and other elements. In the asteroid belt, more than 16 of them are 150-miles across. Vesta, Pallas, and Hygiea are 250 miles in diameter or larger. The biggest one is the dwarf planet Ceres, which is 590 miles in diameter (about one-fourth the size of the moon). The remaining asteroids are significantly smaller. If all the asteroids in the solar system were bundled together, astronomers think they would create an object smaller than the moon.
