Someone watches the telescopes.

The Asteroid Terrestrial-impact Last Alert System is a system of specialized instruments that look for any space rocks that may be near Earth. They are looking for asteroids that pose a threat to our planet. One of the telescopes was in a good position to film NASA slamming a spaceship into an asteroid. You can watch it below.

The Double Asteroid Redirection Test is an attempt by NASA to move an asteroid. The rocky target, Dimorphos, is not a threat to Earth, but the mission is an experiment to see how civilization could alter the path of a menacing asteroid.

The goal wasn't to destroy Dimorphos. The goal is to hit the asteroid with a small craft. Scientists hope to change the trajectory of an asteroid by nudging it. It was expected that the rock would be ejected into space.

Tweet may have been deleted

(opens in a new tab)

The University of Hawaii created a telescope that doesn't peer into the deep solar system for new space rocks. ATLAS acts like a floodlight for asteroids that are close by.

"When smaller objects come to Earth and whizz by, that's when we see them," said Larry Denneau, one of the researchers who heads the ATLAS survey. Each night, the telescopes can see the entire sky.

Denneau said they were looking everywhere to find something close to them.

"We're looking everywhere all the time to find anything close to us."

A 65 foot rock can be spotted by the telescopes in a few days, while a 300 foot rock can be seen weeks out. Small rocks that hit Earth have been spotted by Atlas. The survey found a 13-foot wide asteroid in June. Twelve hours later, it exploded in the sky.

If a space rock surprises us, these telescopes can warn us. The goal in detecting asteroids is to know if a large space rock will hit Earth in the future. NASA and other space agencies will be able to change it's trajectory thanks to that. A small change in trajectory can add up to a big change over time.

Astronomers estimate that only 40 percent of the large rocks found in our solar system are within 30 million miles of us. These are quite large and threatening.

A graph showing the number of NEOs detected by different telescope surveys.

A graph showing the number of NEOs detected by different telescope surveys. Credit: NASA / Center For Near Earth Object Studies

A lot of people are waiting to be found. It's take-out a large-city size.

About 500 such space rocks are found each year by Denneau. There are no known asteroids that will hit Earth in the next 100 years.

Astronomers might find a threatening space rock in the future. A fleet of spacerafts could be sent to slam into that asteroid.