It’s official: NASA has discovered evidence of seasonal water flow on Mars. The astronomy community is psyched, the geology community is psyched…and you may or may not be psyched, which is completely understandable.
But here’s why you should be:
1. It could indicate real, present-tense life on Mars.
The question of whether there’s life on Mars has captivated scientists since the 19th century, but the chain of evolution on Earth has depended on water—something that Mars appeared to lack. Now that we know for sure Martian water is a thing, testing it for microbes is the next logical step.
2. It could indicate past life on Mars—which may have huge implications for life on our own planet.
Mars is 4.5 billion years old, so it’s not inconceivable that as recently as a few hundred million years ago, it was covered with obvious, thriving life. If we discover Mars once hosted a complex planetary ecosystem, learning how it lost that ecosystem could help us avoid meeting the same fate.
Also: There’s a school of thought that says Earth’s first microbes may have arrived from Mars, and a detailed look at Martian organisms (living or fossilized) could help answer that question for us.
3. It reminds us that the “dry planet” model of the universe is outdated.
Victorian-era astronomers Giovanni Schiaparelli and Percival Lowell saw what they took to be artificial canals on Mars, evidence of an advanced civilization. The idea of Mars as mysterious and potentially teeming with life was a viable one even as late as 1964, when the second season of My Favorite Martian aired and the first proposal for Star Trek described Mr. Spock as “Probably half Martian,” but by that point the idea already strained credulity a bit. When the Viking 1 Lander sent back photographs of a lifeless rocky desert in 1976, that put an end to our Martian dreams—and suggested that the universe as a whole was largely made up of these dry, lifeless rocks.
Turns out Mars itself isn’t dry, and might not be lifeless, either.
4. It could speak to how common water, and subsequently life, is.
The Drake equation’s variable ne refers to the average number of habitable planets per star, and while our definition of “habitable” is subject to change, water has historically been a key component of that definition. If Earth and Mars have water, that suggests water—and, subsequently, life—could be much more common than we’d originally guessed.
5. It reminds us that we don’t really know much about the universe.
Outside of Earth (which still has plenty of secrets of its own), there’s no planet we know more about than Mars. We’ve spent more than a half century mapping its surface in detail, testing chemical samples, and so forth, and we’ve only just now discovered that it has seasonal saltwater flows. So how much do we really know about the rest of the solar system—much less the universe as a whole?