Amateur astronomers, space lovers, and people who get off on spectacle are revved up to watch the Perseid Meteor Shower as it peaks on August 11 and 12. And no, despite the fears of some astronomers in the 19th century, the Perseids pose no threat to the safety or well-being of Earthlings.
However, the same can’t be said of Martians or human colonists on Mars. A meteor shower that hits the red planet could deadly. Why?
Let’s back up a second and remind ourselves what a meteor shower is and how it works. When a rock hurtling through space makes its way into Earth’s atmosphere, it starts to burn up like a hurtling ball of fire. If you’re watching the sky at night (or if there’s a particular intense burn during the day), you’ll see a radiating streak move past your eyes. Sometimes, a collection of space debris has a shared origin, a source close to Earth that has caused the shedding off a ton of meteors, and those individual rocks find their way towards the planet. In the case of the Perseids, that would be the Swift-Tuttle comet. A ton of individual rocks from the comet’s cloud make their way into our planet’s atmosphere as Earth nears the comet every summer, and voila — you have one of the best and brightest meteor showers known to humans.
Meteor showers can happen on other planets too. All you need, as you might have already ascertained, is a robust atmosphere that can burn up the little buggers and create a lit up spectacle in the sky.
But a rock that doesn’t have a thick atmosphere won’t always burn up incoming meteors quickly or strongly enough before they hit the dirt. Mars currently has an atmosphere less than one percent as thick as Earth’s. The red planet gets pummeled with more asteroids than the blue planet — and those fragments tend to be several times smaller than the rocks that pelt the surface of the Earth.
Now to be fair, meteor showers do happen on Mars. The upper portions of the atmosphere share some similarities with Earth, so a shooting star that’s set ablaze in the Martian sky will appear a lot like one in Earth’s sky. Of course, if it survives those higher altitudes and remains intact, at least a part of the chunk has a very good chance of making a dent in the ground.
If a comet (or some other strange flying rock) managed to let loose a ton of high-speed, heavy-duty meteors as it flew past Mars, the red planet could get lit up like a clumsy tween playing paintball for the first time. Anyone sitting idly by on the ground would get to see a flurry of shooting stars turn the Martian sky into a Christmas tree — and then watch the ground around them transform into a miniature apocalypse.
Of course, it would have to take an extremely intense type of meteor shower to really do damage to the surface. The Perseids, for example, are one of the most spectacular meteor showers we’re able to observe, but they’re still a result of a lot of particulate matter (relatively speaking). If the Perseids struck Mars, colonists would likely be fine, but they would certainly want to be fine indoors.
Unfortunately, the closest we’ve ever gotten to observing a meteor shower on Mars was when the Spirit rover picked up an image of a shooting star zipping through the sky, back in March 2004. Once we actually start sending more instruments to Mars — and especially once we start getting astronauts to the red planet within a couple more decades — we might finally experience the incredible spectacle (and assess any potential threat) of a meteor shower on our nearest neighboring world.