Today's topic is the asteroids known as Trojans. There are two groups of these asteroids: one known as the "Trojans," and the other known as the "Greeks".
These asteroids are locked in the L4 and L5 points of the planet Jupiter. To put it briefly, L-points are 5 locations in a two-body system (the Sun and a planet, for example), where smaller objects (satellites, asteroids, et cetera) can be held purely by the force of gravity. It's a topic for another day, so if you'd like to know more, I suggest you google "Lagrangian Points."
Anyway, that means these asteroids are grouped ahead and behind of Jupiter, sort of it's stellar "entourage." These are represented in the attached picture by the light green dots around Jupiter. You'll probably (definitely) notice the large mass of white dots between Earth/Mars and Jupiter. This is the asteroid belt.
THIS IS WHERE IT GETS MISLEADING. PLEASE PAY CLOSE ATTENTION: contrary to what the picture shows, the asteroid belt is
mostly empty space. That means it's highly unlikely you'll hit anything, unless you aim for it. That is because these thousands of points shown are really really small. For example, the three biggest asteroids (Vesta, Pallas, and Hygiea) all only have a diameter of slight over 400 kilometers. Ceres, a dwarf planet located within the asteroid belt, has a diameter of only 950 kilometers, making it the largest object in the belt. Everything else is under 400 kilometers in size, even down to the size of a dust particle. Because of the small sizes of these objects, they tend to be thinly dispersed among that region, though some of the "larger" asteroids will get pushed near each other and start forming "families" (this is caused by the gravitational pull of Jupiter). However, despite this, it is pretty safe to travel through this region. That's why we've been able to send probes to places such as Jupiter and Saturn, with New Horizons heading towards Pluto.
Also, there's a spacecraft with an ion drive that's flying around the asteroid belt and that's pretty freaking awesome.
Picture:
https://www.dropbox.com/s/cf42xnj7vblwt4p/InnerSolarSystem-en.png
