GoKawiilWhat if we aren’t alone in the universe? People have been speculating about the possibility of alien life forms at least since Lucian’s A True Story, some 1,800 years ago. In modern times, much of that has centered on our near neighbor Mars.
Sometimes those life forms are dangerous, probably never more so than in the various versions of The War of the Worlds. Sometimes they’re more congenial, as in the ’60s sitcom My Favorite Martian. Either way, we can’t stop wondering, what if?
The fiction is fun, but it’s science that will answer the question more definitively. And the science has been getting closer to the mark since astronomer Percival Lowell theorized in 1890 that intelligent life built a series of canals on the red planet.
Nowadays we have landers and rovers on the Martian surface, and spacecraft making observations from orbit. We may even get boots on the ground in the years ahead, whether through NASA’s eventual follow-ons to the Artemis moon missions or courtesy of would-be Mars colonizer Elon Musk (though he has missed his original target of 2025).
It helps that Mars is the nearest planet that isn’t a toxic hellscape with surface temperatures hot enough to melt lead. There are theories about life on Venus, but until scientists can create something that survives longer than 2 hours on the surface, Venus isn’t really in the conversation.
So where do we stand, exactly, on finding life other than on Earth?
This is not a fossilized duck on Mars. It’s just a rock. NASA/JPL-Caltech/MSSS/Andrea Luck
How likely is life on Mars?
It’s a complex question because many factors have to align for a planet to support life. It has to be in the habitable zone of a star, close enough to support liquid water but far enough away to not get scorched. It also needs an atmosphere to hold in some of that heat and a rocky surface so that life has somewhere to live. That rocky surface could be covered in water, but the point is that it can’t be a gas giant like Jupiter.
Once you get that right, the planet needs the right mass and gravity and a molten core of liquid metal to generate a magnetic field, which protects the surface against the most harmful rays that come from the host sun. The correct chemical ingredients must also be present, since life can’t exist without the fundamental building blocks, such as carbon, hydrogen, nitrogen, oxygen and phosphorus. All of these elements have to work in balance with one another to create an ecosystem that is just right for supporting life.
... continue reading