Scientists offer the possibility that if there are intelligent aliens in our galaxy, they may be swimming in cold, dark oceans covered by miles of ice.
Are intelligent extraterrestrial life living underwater instead of on the surface?
Enrico Fermi, Nobel Prize-winning physicist, once asked: “Where is everybody?” By everybody, he meant intelligent extraterrestrial lifeforms. After all, the galaxy is already about 13 billion years old. The Milky Way is no spring chicken, even in galactic terms. It also has billions of possibly habitable worlds. According to Fermi, we should have made contact with intelligent life beyond Earth by now--a sentiment that gave rise to the Fermi paradox. However, as far as we know and can verify, we haven’t. So, to repeat Fermi, where is everybody?
There are many possible answers to this question; frustratingly, we still don’t know which one is correct. Maybe the aliens out there are still just microscopic organisms incapable of making contact with lifeforms on other planets. Maybe they’re keeping to themselves, observing us from afar and holding off on making contact. It’s also possible that maybe, we truly are alone.
Europa, one of Jupiter's moons, have oceans of liquid water under its surface ice.
That last possibility, however, is something that many scientists refuse to accept. Thus, just recently, planetary scientist and principal investigator for NASA’s New Horizons mission Alan Stern came up with another possible answer to where everybody is. According to Stern, it’s possible that intelligent life is widespread throughout the galaxy, but that they’re cut off from making contact with other life forms outside their homeworld. This is because these aliens may be living in oceans, with miles and miles of ice above them.
Stern says that worlds with buried oceans are likely to be common in the galaxy. In fact, there are a number of these worlds just in our own backyard. The Jovian moons Europa, Callisto, and Ganymede, as well as the Saturnine moon Enceladus, all have oceans of water underneath their surface. Even former planet Pluto, as well as the biggest Saturnine moon Titan, may have oceans under their crust.
Interestingly, Earth is the only planet we know of that has water on its surface, not under it.
Another thing that corroborates Stern’s hypothesis is that underground oceans are a more stable environment. Thus, if there were intelligent aliens in those underground oceans, they would have more time to evolve and grow more complex. This is because they have fewer threats--solar flares, radiation, a deadly atmosphere--to contend with.
Where is everybody?
However, there’s a price to pay for that kind of protection and the opportunity to grow without too many threats to your survival. It’s likely that if these underground alien civilizations were trying to communicate with others in the universe, they would be having trouble making contact.
"If they have technology, and let's say they're broadcasting, or they have city lights or whatever — we can't see it in any part of the spectrum, except maybe very-low-frequency [radio]," says Stern.
Stern’s theory, while with merits, is not completely watertight. For example, if intelligent aliens lived in underground oceans, how would they know that there are other worlds beyond their atmosphere? After all, they wouldn’t have a view of the stars that would indicate to them that there is an entire universe out there. They would need to tunnel to the surface while also making sure that they were still submerged in water in order to survive. Also, even if they were capable of interplanetary travel, it would be complicated. After all, they’d need to fill their vessels with water, which would weigh down the ship.
These are holes in the theory--ones that Stern accepts. He doesn’t think that his ideas definitively answer the Fermi paradox, but they do contribute to the discussion.
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