They zip through space at high speeds and are nearly impossible to track with conventional ground-based radars. The alien invaders are only meteoroids, specks of dust shed by comets and asteroids, and are harmless to Earthlings. The minuscule meteoroids are only a few tenths of a millimeter in size and weigh less than 10-4 grams.
Meteoroids do, however, pack a considerable punch.
They race past Earth at speeds anywhere from 22,000 to 157,000 mph. Collisions with high-speed space dust can electrify satellites, scrambling software and triggering mistaken control procedures. Meteorids are impossible to avoid entirely simple because there are so many of them. If they know when Earth is about to enter a dense swarm, ground controllers can orient their craft to minimize cross section or point sensitive components away from the incoming particles. This is what we recommend when we give satellite operators our meteoroid forecasts.