Asteroid grows two tails after DART spacecraft collide
Astronomers have been keeping a close eye on the asteroid Didymos since the historic successful DART mission crashed spaceship last month. And now Hubble has detected something unexpected – the asteroid has sprouted two tails.
from NASA DART mission was designed as a test for a planetary defense system. A spacecraft was deliberately crashed into a small asteroid called Dimorphos, to see if the impact was enough to change its orbit around a larger rock called Didymos. If it worked, it could give us a way to defend ourselves if we ever were to spot an asteroid on a collision course with Earth.
Sure enough, follow-up observations showed the test to be a success, with its initial 12-hour orbit being 32 minute shortcut. But that wasn’t the only result – two days after impact, the SOAR telescope in Chile photographed the asteroid and found it had grow a tail which stretched for more than 10,000 km (6,000 miles).
Hubble continued to observe the asteroid, taking 18 images of Didymos in the weeks after impact and spotting some interesting developments. The first was that the ejected material expanded and faded over time – nothing too surprising there. But the unexpected discovery was that between October 2 and October 8, the asteroid developed a second tail.
In the image above, the top tail is the new one, while the DART spacecraft has approached from the top left of the frame. The Sun is off on the left side of the image.
It may be unexpected in this case, but the discovery is not entirely unprecedented – comets and other active asteroids are known to grow extra tails in the old days. Exactly how this second tail formed remains unclear, but the data will be further analyzed to find an answer, with several scenarios deemed possible.
The Didymos system will continue to be watched for any further changes.
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