Since human beings first observed other heavenly bodies, we have questioned if we were alone in the universe. We’ve looked closer, by directing a lander to the Moon and rovers to Mars, and we’re also looking far, sending satellites on tasks outside our solar system and studying the spectra of planets circling other stars in the “goldilocks zone.” But lately, with the detection of a saltwater ocean on Jupiter’s moon Ganymede and huge bodies of liquid methane on Saturn’s moon Titan, life might be closer to our home than we previously thought—and it might look a lot diverse than we ever predicted. Scientists are anxious to discover life on other planets because it might help us understand some important questions about ourselves and also about the Universe. On Earth, we have a pretty good understanding of atoms, molecules and how energy works between and within them—we understand the fundamental requirements and conditions for life here.
Vance says “We will want to be careful about contaminating Earth. Say we find microbes in subglacial fluids on Mars. Any space agency would worry about even having astronauts come into contact with them, both for the sake of the astronauts’ health and for that of the microbes.”
In fact, NASA has a complete department devoted to ensuring Earth’s protection if we should find life on another planet and to aid them figure out what to do next. Sending probes and rovers as we’ve already done on Mars is an effective way to get some elementary information about the elements and environments on a particular world. But if they find a particularly promising sample, and it’s believed to be safe, scientists will want to bring it back to Earth. Back on Earth scientists can use powerful microscopes and other equipments to look at the sample’s elementary constituents, as they did with the lunar rocks and may do with samples from other worlds. Scientists would have a lot of queries about the organism’s chemical components, especially about its structure, how it develops, what it eats and how it moves. But the most rudimentary of all these question is if an organism (living or dead) has DNA related to our own, or if it’s something diverse entirely.
After decades of focusing efforts on just a limited key molecules that would provide a clue if life was present on another planet, scientists are now beginning to think more resourcefully about what an organism might look like or be made of. On Titan, for instance, life might be methane-based—instead of carbon-based—swimming along in an ocean empty of oxygen or its compounds (like H2O). Though some might disagree, Vance doesn’t think that finding life on another planet would be a danger to Earthlings.
In the end, life on other planets would do a lot to help us comprehend ourselves and to answer, “A lot of essential questions about what life is about,” as Vance says. “Finding life on another planet might help us crack that code. To me, that opens up an opportunity for adventure.”