Asteroid shattered by NASA now reveals a 6,200-mile comet-like tail

Here’s more evidence that NASA successfully slammed a spacecraft into an asteroid on September 26, 2022.

The effect of NASA’s $325 million Double Asteroid Redirection Test (DART) probe, which successfully hit asteroid Dimorphos — an asteroid moon orbiting a larger asteroid called Didymos — was captured two days later by the SOAR telescope in Chile, operated by the National Science Foundation’s NOIRLab.

In the photo above, you can see a 6,200-mile/10,000-kilometer trail of dust and debris blasted from Dimorphos’ surface. “It’s amazing how clearly we were able to capture the structure and magnitude of the aftermath in the days following the impact,” said Teddy Kareta of the Lowell Observatory, who used the 4.1-metre SOAR telescope to study the texture of the surface of Dimorphos to study how much material was ejected by the collision, how quickly it was ejected, and the distribution of particle sizes in the expanding dust cloud.

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DART’s 15,000 mph impact was the first-ever attempt at planetary defense. NASA’s goal is to see if it’s possible to change the trajectory of a potentially dangerous object in space by bumping into it. The aftermath of the 500 kg DART spacecraft’s kinetic impact on Dimorphos will be studied both immediately and over many years to see if it’s a viable solution should a truly threatening object come our way.

The hope is that Dimorphos’ speed will change by 0.4 mm/s, which in turn will slightly change Didymos’ trajectory. When that happens, the time it takes for the smaller asteroid to orbit Didymos shifts by a few minutes.

“Now begins the next phase of work for the DART team as they analyze their data and observations from our team and other observers around the world who were involved in the investigation of this exciting event,” said Matthew Knight of the US Naval Academy, who the observations also worked on this. “We plan to use SOAR to monitor the ejections over the coming weeks and months.” Their work will help reveal whether the collision caused huge chunks of rock to disintegrate, or whether it was mostly dust.

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Last week, NASA released images (above) of the episodes, taken simultaneously in different wavelengths of light by its two major space telescopes, the Webb and Hubble. In the coming months, scientists will use Webb’s Mid-Infrared Instrument (MIRI) and Near-Infrared Spectrograph (NIRSpec) to continue monitoring Dimorphos ejecta. Hubble will monitor Dimorphos 10 times over the next three weeks to see how the ejecta plume changes.

Didymos and Dimorphos are two near-Earth asteroids that orbit each other, which is not uncommon. The larger of the two bodies in this binary system is Didymos, at 2,560 feet/780 meters in diameter, and the smaller Dimorphos, at 530 feet/160 meters (also called “Didymoon”), orbiting Didymos. They have a two-year orbit around the Sun that is slightly inclined to those of the planets and also slightly eccentric.

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They can be found just past Earth to just past Mars. DART’s impact occurred when the binary asteroid was 6.8 million miles/11 million km from Earth.

The European Space Agency’s follow-up mission Hera – due to launch in 2024 and arrive in early January 2027 – is an asteroid rendezvous spacecraft designed to see if DART works.

Hera will examine both Didymos and Dimorphos closely using lasers, a star tracker, a thermal imaging camera, and accelerometers. It will see if the impact crater left by DART on Dimorphos (which it will reach to within 200 meters) has changed Didymos’ trajectory.

I wish you clear skies and big eyes.