‘Potentially Dangerous’ Monster Asteroid Has Been Seen Largest in Years: ScienceAlert

Twilight-watching astronomers have found three previously unknown asteroids near Earth. One is the biggest potentially dangerous asteroid discovered in eight years.

It measures about 1.5 kilometers (almost 1 mile) across and is in orbit that could bring it close enough to Earth in the future to pose a problem.

The other two asteroids have paths that are completely and safely closer to the sun than Earth’s orbit. That doesn’t make their discovery any less exciting, contributing to a count of hard-to-find objects that will allow us to better characterize the population of near-terrestrial objects.

Most of the small planets in the solar system – objects in direct orbit around the sun that are not planets or comets – have been discovered at greater orbital distances than Earth’s. There’s the asteroid belt in between Mars and Jupiterthe Kuiper belt beyond Neptune in which Pluto is located, and a number of other rocks, such as Greek and Trojan asteroids that share planetary orbits.

Closer to the sun, not much has been discovered in terms of minor planets, and for very good reason. We need to look at a large, bright star, whose dazzling light makes small, dim asteroids virtually undetectable. That means we’re more likely to find objects if we look away from the sun in a direction toward the outer solar system.

To have a chance of spotting an asteroid in the solar system, astronomers must wait until dawn and dusk, when the sun’s glare is usually below Earth’s horizon, providing just enough light. to illuminate the inner asteroids that could hurtle through space.

A research team led by astronomer Scott S. Sheppard of the Carnegie Institution for Science conducted such a search for large areas of the sky closer to the sun than Earth and Venusleading to some fascinating discoveries.

a wash 2021 PH27, an asteroid with the shortest orbit of all asteroids found so far, at just 113 days. Then there’s the 2021 LJ4, which also completely orbits the sun within Earth’s orbit. Both are known as Atira asteroids.

“So far we have found two large near-Earth asteroids with a diameter of about 1 kilometer, a size we call planet killers,” Sheppard says:.

“There are probably only a few near-Earth asteroids of similar size left, and these large undiscovered asteroids probably have orbits that keep them within the orbits of Earth and Venus most of the time. Only about 25 asteroids with orbits completely within Earth’s orbit have been discovered so far because of the difficulty of observing the glare of the sun up close.”

The third asteroid, 2022 AP7, is known as an Apollo asteroid. These are asteroids with elliptical paths that take them from a space closer to the sun and out of Earth’s orbit. Through cross our orbit, Apollo asteroids like 2022 AP7 could get close enough to our planet to risk a collision, causing they have a classification of “potentially dangerous”.

There are more than 2,000 potentially dangerous asteroids (the the largest of which is about 7 kilometers wide) which we are fortunate to know. Knowing them allows us to model their orbits and calculate if and when they are likely to come within Earth’s dangerous range. With enough notice, we may be able to do something about it, such as: hitting a spacecraft against their surface to change their course.

It is also important to discover new Atira asteroids. Our understanding of the population of minor planets in the solar system is based primarily on a count of space rocks in the more distant regions. If we have a better idea of ​​what’s inside the solar system, we can tell more about the dynamics of the solar system – how asteroids are transported to different regions, as well as more accurate models of the system’s evolution over the course of time. time.

“Our DECam search is one of the largest and most sensitive searches ever conducted for objects in Earth’s orbit and near Venus’ orbit,” Sheppard says:. “This is a unique opportunity to understand what types of objects lurk in the inner solar system.”

interesting, despite being more sensitive to smaller objects, the research has uncovered a larger number of larger asteroids – which are at least a kilometer wide. This could mean that smaller asteroids are less stable in the Solar System’s interior, or more prone to break up in the intense thermal and gravitational environment closer to the Sun.

However, smaller asteroids may be more difficult to detect. This is an excellent reason for more sensitive investigations in the future.

The article describing the three asteroids was published in: The Astronomical Magazine.