If you had to guess how many Starlink satellites burn up in Earth's atmosphere on an average day, how many would you pick? This isn't a trick question - SpaceX is deorbiting about one or two satellites daily, and that number is only going to grow.

What that means for our planet isn't entirely clear, says Harvard astrophysicist and space tracker Jonathan McDowell. Even so, Starlink isn't the space junk risk that some other satellite operations are.

McDowell commented on the massive volume of reentering Starlink satellites to science news site EarthSky last week. He explained that once Starlink and other planned low Earth orbit constellations together total about 30,000 satellites, roughly five could reenter the atmosphere each day, given an average replacement cycle of around five years.

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