The recent observations prove that not all asteroids are boring objects simply hanging out in space.

Gone are the days when we believed asteroids to be just large rocks hanging out in space. As space exploration has progressed, we have come to note that they are much more complex than that.

A great example of this is the asteroid Didymos, which according to a new study published on Monday, is literally spitting rocks into outer space due to the excessive speeds at which it is spinning.

Didymos has been studied for quite some time now in preparation for NASA’s DART (Double Asteroid Redirection Test) and the European Space Agency’s Hera mission.

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ESA

So what would happen if we ever came face to face with such an apocalyptic scenario?

A comet that will make a (somewhat) close approach to the Earth in September 2024 is already creating excitement among amateur astronomers. Comets are unpredictable beasts, and a great many have proven disappointing – but C/2023 A3 (Tsuchinshan-ATLAS) has many of the characteristics required to put on the best display for at least a decade.

Comets visit the inner solar system quite frequently, but few can be seen with the naked eye. Most are either regular visitors (short period) that have been slowly losing material on previous approaches to the Sun and don’t have enough left to be very bright. Others never get close enough to Earth to put on a show.

Tsuchinshan-ATLAS passes both those tests. Its orbit is so long it there is debate as to whether it visited the inner solar system 80,000 years ago, or if it never has. At closest approach, it will be 58 million kilometers (36 million miles) or just under 0.39 AU (Earth-Sun distance) from the Earth.

By understanding how asteroids function, we can know more about how to knock them off course.

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The DART mission moved an asteroid, setting the stage for planetary defense strategies that could avoid collision with more dangerous objects.

This larger-than-expected result shows the change in Dimorphos’ orbit was not just from the impact of the DART spacecraft. The larger part of the change was due to a recoil effect from all the ejected material flying off into space, which Ariel Graykowski of the SETI Institute and colleagues estimated as between 0.3 percent and 0.5 percent of the asteroid’s total mass.

A First Success

The success of NASA’s DART mission is the first demonstration of our ability to protect Earth from the threat of hazardous asteroids.

What would we do if we spotted a hazardous asteroid on a collision course with Earth? Could we deflect it safely to prevent the impact?

Last year, NASA’s Double Asteroid Redirection Test (DART) mission tried to find out whether a “kinetic impactor” could do the job: smashing a 600kg spacecraft the size of a fridge into an asteroid the size of an Aussie Rules football field.

Early results from this first real-world test of our potential planetary defense systems looked promising. However, it’s only now that the first scientific results are being published: five papers in Nature have recreated the impact, and analyzed how it changed the asteroid’s momentum and orbit, while two studies investigate the debris knocked off by the impact.