Before witnessing the impact of DART on Dimorphos, the small satellite LICIACube turned to another target. He saw the earth and the moon, two small fuzzy dots, 11 million kilometers from him.
The DART probe crashed into an asteroid. However, everything was planned: it was a test, the very first in human history, to try to change the trajectory of an asteroid in space. The effect of DART could be immortalized in impressive pictures. In particular, a small satellite called LICIACube was used to track the diversionary exercise of the asteroid Dimorphos in space.
But LICIACube also had time to observe something else. “Before witnessing the impact of the DART mission on Dimorphos, the Italian satellite aimed its instruments at our planet and its satellite,” has indicated LICIACube mission Twitter account, October 2, 2022. In fact, the small satellite was able to transmit an “interplanetary selfie” with two blurry dots, which turned out to be the Earth and the Moon.
The earth, a blue spot, 11 million km away from LICIACube
The Italian space agency does not give the exact date when this picture was taken. What we do know is that the capture predates DART’s collision with Dimorphos, which occurred on the night of September 26-27. When the impact took place, the mission was at a distance of 11 million kilometers from our planet. Looking at this photo of Earth, it seems rather dizzy to think that astronomers around the world started monitoring the aftermath of the DART crash on Dimorphos from this little blue speck.
How will we know if the DART ship deflected the asteroid it crashed on? It will take time: scientists will use the fact that Dimorphos is a moon orbiting another asteroid (Didymos). The eclipses from this pair of asteroids make it possible to capture regular falls in brightness over time (since, from our perspective, one of the two asteroids passes before the other, then vice versa). By tracking the times when eclipses occur, astronomers can determine how long it takes for Dimorphos to orbit Didymos. We expect this parameter to gradually change since the impact of DART.
Remember that Didymos and its moon do not pose a proven threat to our planet. This binomial is certainly placed in the category of potentially dangerous objects. This means that it comes close to our planet on its trajectory and is therefore monitored. So far, however, no concrete risk of an asteroid impact on Earth has been proven. However, this does not preclude preparing for this case.
For further