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Birthday · March 9, 2023

DART vs Dimorphos

March 9, 2023

You share your birthday with the light of distant galaxies that has been traveling for millions of years just to arrive here, now, alongside...

DART vs Dimorphos

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APOD published March 9, 2023. Full image credits are on the original APOD entry below. A publication-date match, not a photo taken on your date. Independent of NASA.

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DART vs Dimorphos

Original APOD · March 9, 2023

On the first planetary defense test mission from planet Earth, the DART spacecraft captured this close-up on 26 September 2022, three seconds before slamming into the surface of asteroid moonlet Dimorphos. The spacecraft's outline with two long solar panels is traced at its projected point of impact between two boulders. The larger boulder is about 6.5 meters across. While the DART (Double Asteroid Redirection Test) spacecraft had a mass of some 570 kilograms, the estimated mass of Dimorphos, the smaller member of a near-Earth binary asteroid system, was about 5 billion kilograms. The direct kinetic impact of the spacecraft measurably altered the speed of Dimorphos by a fraction of a percent, reducing its 12 hour orbital period around its larger companion asteroid 65803 Didymos by about 33 minutes. Beyond successfully demonstrating a technique to change an asteroid's orbit that can prevent future asteroid strikes on planet Earth, the planetary-scale impact experiment has given the 150-meter-sized Dimorphos a comet-like tail of material.

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