A Search for Alien Life

Are we alone in the universe?

Whether you are coming at this as a biologist, anthropologist, or religious scholar, this is a question which has occupied — and befuddled — thinking minds for centuries, if not millennia. And while I cannot even begin to resolve the issue on a scientific basis, I can admit to having invested many and more brain cells in an attempt to clarify my own personal thoughts (and I may even share them before this post is done).

In the hopes of taking another step toward answering the “are we alone?” conundrum, NASA is sending a probe to study Europa, the smallest of the four Galilean moons of Jupiter (click here for a summary of Europa from Wikipedia). A couple stats, just to get them out of the way:

Based upon what we can see through telescopes and from the few fly-bys that NASA has already conducted, Europa is very much like the earth in composition (silicate rocks with a metallic core), and the earth’s moon in size. At roughly five hundred million miles from the sun, it is very cold there: surface temperatures at its equator do not get much above -260° F, so I guess we shouldn’t expect to find a steaming cup of Europa-grown coffee waiting for us if we ever get there.

Europa appears to be covered with liquid water — yep, just like the earth, but without the continents and islands sticking out. What is exposed on the surface is ice, much like the floating sea ice at earth’s north pole. The difference with Europa is that its ice covers the entire moon, and is estimated to be ten to twenty miles thick. That’s a lot of ice!

All evidence points to the probability that there is heat being generated within the moon, as well as supplied by tidal drag from massive Jupiter. This energy seems to be resulting in plate-like motions that have been disrupting the surface layer of ice, causing it to be broken by linear ridges and fractures called lineae. The larger fractures can be more than ten miles across.

It seems obvious from the image — based upon the Principal of Cross-Cutting Relationships which is so fundamental that it’s gotta be Universal — that there have been multiple episodes of fracturing. It is also apparent that some of older lineae have been offset by the younger fractures cross-cutting them, with the older fractures on either side of the younger cracks having moved relative to each other.

The lineae are assumed to be caused by flexing of the brittle surface ice as it sits on an underlying “ocean” of liquid water, which is estimated to approach sixty miles deep. That’s a lot of water! This layer is assumed to be able to stay in the liquid phase due to the internal and tidal energy mentioned above.

This liquid ocean is to be the focus of NASA’s search for life. To this end, the Europa Clipper was launched from the Kennedy Space Center on 14 October 2024. Jupiter is a long way away, so the spacecraft will use gravity assists from Mars on 1 March 2025, and Earth on 3 December 2026, to increase its velocity. It will still take over five years to travel the distance, arriving at Europa on 11 April 2030.

When it gets there, it will perform a series of forty-nine flybys of Europa while in orbit around Jupiter, and learn as much about the ice and water-covered moon as can be determined using remote sensing. Click here for a summary of the mission from the New York Times.

Any attempt to land (or should the term be “to ice”) on Europa will have to wait for a later mission. Sadly, it’s safe to assume I won’t still be around to find out what they learn (heck, I’m just hoping to still be here in 2030 to hear what the Clipper can tell us).

Looking at Europa as one of the better chances of finding life within our local solar system isn’t new. This is something we considered in detail when I taught Astronomy at Grants Pass High School back in the 1990s. The overall concept at the time was very much the same, with one fundamental difference (which is what I want to focus on at the close of this rant).

The idea then was to send a nuclear-powered thermal drill and attempt to melt through the surface ice and sample the water beneath it, in the logical assumption that finding viable organisms was highly likely. All good, as far as the technical aspect was concerned, but what about the moral?

Even back in the 90s, many were beginning to question the overall appropriateness of our technological society, and a concern was voiced (to the point of severely disrupting the concept) that we, as a species on the fast-track to a self-induced environmental catastrophe, didn’t have the moral right to drill into a previously uncontaminated biosphere and pollute it with our stuff.

I have not yet heard a similar concern mentioned regarding any future Europa program designed to penetrate the ice and sample the underlying ocean, but suspect that, as we get closer to actually sending in the equipment, it will become a topic of raging debate.

I leave it to you to decide which side of the discussion floats your boat. For myself, I think I’d like to keep our nukes and microbes as far from Europa as possible.

Reading back through this, I also notice that I have yet to give my two cents on the possibility of life elsewhere in the universe. The short version is a resounding “Yes” (I promise a more detailed discussion on the Origins of Life in a future post).

Until then, I leave you with a quote from Dr. Eleanor Arroway in Contact (played by Jodie Foster), speaking to a group of school kids at the end of the movie. (BTW: Contact was such an appropriate movie that I would actually devote three class periods to share it with my Astronomy students — I encourage you to watch it.) Anyway, to quote Dr. Arroway (who actually borrowed the sentiment from her father, and Palmer Joss — “a man of the cloth… without the cloth”):

The universe is a pretty big place. It’s bigger than anything anyone has ever dreamed of before. So if it’s just us… seems like an awful waste of space.