Welcome to Molecular Mondays! Every other Monday, we examine the atoms and molecules that serve as the building blocks of our universe, both in reality and in science fiction. Today, we turn our attention to:
Hydrogen Peroxide on Mars
The surface of Mars is covered with hydrogen peroxide, a strong oxidizing agent. Here on Earth, we use hydrogen peroxide (chemical formula H2O2) as a disinfectant, among other things.
So I guess that’s it. My hope that one day we’ll discover native Martian organisms is crushed. How could life survive on a planet covered in disinfectant?
The Office of Planetary Protection must be happy.
This could be good news for the Office of Planetary Protection (real thing, not kidding). The O.P.P.’s job is to ensure that NASA doesn’t accidentally contaminate other worlds with microorganisms from Earth.
They don’t worry about contaminating Venus because Venus is self-sterilizing (in many more ways than one). So with all that H2O2 lying around, is Mars a self-sterilizing planet too?
Turns out it isn’t. Researchers found that while microbes from Earth would probably struggle on Mars, enough could survive to cause problems. Despite all that H2O2, we could still contaminate Mars if we’re not careful.
And if Earthly microorganisms can survive, surely native Martians—which would have evolved in this peroxide-rich environment—would be okay as well.
Wait, did you say oxidizing agent?
Long ago, life on Earth was nearly wiped out by a certain oxidizing agent called oxygen. This event is known as the oxygen catastrophe.
Free oxygen can rip chemical bonds apart, to the detriment of most early organisms on Earth. And yet, life adapted. Not only that: life figured out how to take advantage of an otherwise bad situation.
Perhaps a similar story could have occurred on Mars. If Martian life forms exist, maybe they “breathe” hydrogen peroxide as we breathe oxygen, using it to power their bizarre, alien biochemistries.
Some experts would argue that Mars’s hydrogen peroxide is the final proof that life cannot exist anywhere near the planet’s surface. But perhaps, quite to the contrary, hydrogen peroxide might be the very thing that makes Martian life possible.
At the very least, it’s enough to give science fiction writers something to think about.
P.S.: Regular readers of this blog already know that Martians are convinced life cannot exist on Earth. After all, oxygen can be used as a disinfectant. How could life survive on a planet with an atmosphere full of disinfectant?