Earth is being “followed” by a chunk of the Moon
Scientists don’t know how it might have broken off from the Moon
NASA plans ‘Armageddon’-style mission to crash into asteroid’s moon
The planetary defense mission is anticipated to make an impact between Sept. 26 and Oct. 2, 2022
‘Potentially hazardous’ asteroid expected to pass by Earth
The asteroid is classified by NASA as a "potentially hazardous object"