They are concentrated between the Mars and Jupiter.
Scientists may not have named all of the asteroids in the asteroid belt because there are so many that they are hard to keep track of.
Because they have been observed and space probes have navigated through them.
At the same time that the Earth (and the other planets) formed : 4.5 billion years ago.
with computers and devices
About the same age as the time of formation of the solar system: 4.6 billion years to 4.7 billion years.
Asteroids, even very large ones, actually come close to earth regularly and cause no harm and no effect on life on earth. The concern would be a large asteroid crashing into the earth.
Scientists study asteroids to better understand the early solar system.
Scientists believe that asteroids originated from the leftover material from the early solar system's formation, primarily from the asteroid belt located between Mars and Jupiter.
Scientists think that the asteroid belt is a group of planetesimals (solid objects) that are caught between the gravity of Jupiter and the Sun.
They are from bigger asteroids. Two big asteroids crash into each other and little pieces come off the big asteroids.
It doesn't seem that scientists are anywhere near to knowing the total number of asteroids in the Kuiper belt.
There are currently no known asteroids predicted to hit the Earth in the near future. Scientists continuously monitor asteroids and comets that come close to Earth, and there are no imminent threats at this time.