Why do scientists care about tiny space rocks?
Tiny space rocks are leftovers from when the planets formed, so they help scientists learn how Earth was made and where water and life's ingredients came from.
You might think scientists would only be interested in giant asteroids, but small space rocks are hugely important.
First, they are time capsules. Most meteorites are leftover building blocks from about 4.5 billion years ago, when the planets were forming. Earth's own ancient rocks have been melted, squashed and recycled many times, so they cannot tell us much about those early days. Meteorites can. They show what the first solid materials were like and how quickly planets grew.
Second, they tell us about other worlds. Some meteorites come from the Moon, Mars and the asteroid Vesta. They are the only pieces of those places that scientists can study in laboratories, apart from the few samples brought back by spacecraft.
Third, they help us understand where Earth's water and the ingredients of life came from. Some meteorites contain water, carbon chemicals and amino acids.
Fourth, studying small space rocks and how they break up in the air helps us prepare for bigger ones, and protect Earth.
Even dust is useful. Tiny grains collected from Antarctic snow and from space contain material from comets and stars. Small things can answer very big questions.