Free Astronomy Magazine November-December 2022

D imorphos, the satellite of Didymos, had a frontal impact with the spacecraft DART on September 26. The impact produced a reduc- tion on the size of the orbit and an increase in its speed. Measurements from space- and ground-based telescopes determined the amount of this reduction. With this information, astronomers will predict if it is possible to avoid future collisions between our planet and any aster- oid. LICIACube is an Italian spacecraft which followed DART to record the impact at close distance. [NASA/Johns Hopkins University] T he system Didymos-Dimorphos is an eclipsing binary. That means that there are periodic eclipses visible in the light curve (below), as the secondary revolves around the primary. By timing these eclipses, it will be possible to measure the new orbital period with extreme precision, using ground-based telescopes. [NASA/Johns Hopkins University APL, image modified by the Author]