One of my pet peeves has always been the insertion of unfamiliar terms and foriegn phrases in written works without a) context, b) the proper pronunciation, and/or c) a reason for the inclusion to be there (beyond showing readers that the author knows what they mean). The first time I read about ‘coureur de bois’ in a document I was using in my classes, I went straight to our French teacher, David Morin. I said, “Oh, I hate when they do this. What the heck is a ‘coureur de bois’?” David’s explanation was along the lines of, “Loosely translated, it means ‘runners of the woods’ or ‘boys of the woods’. It was used for the French-Canadian traders who first explored New France and began trading furs with the First Nation people.” This explanation became a constant point of clarification every time this document was cited in my class. The following is a good example of something that would have frustrated me had it not been cleared up in the book recommended by my old friend, NASA In The Schools presenter Ralph Winrich.
‘Oumuamua is a Hawaiian word (pronounced “oh moo ah moo”) loosely translated as “scout.” It is the name the International Astronomical Union attached to an object that passed through our inner Solar System in the fall of 2017. The ‘official’ IAU designation is ‘1I/2017 U1’. The easier to remember ‘Oumuamua handle comes from the geographical location of the Pan – STARRS telescope that had discovered this object. Pan-STARRS is actually a network of telescopes and high-definition cameras located on the top of the dormant Haleakala volcano on the island of Maui. The mount top location of the observatory reduces the atmospheric interference giving astronomers a clearer view of our celestial neighborhood. Only space based telescope platforms offer better views from their lofty orbits beyond the Earth’s atmosphere. In his book Extraterrestrial – The First Sign of Intelligent Life Beyond Earth (2021 – Houghton Mifflin Harcourt), Harvard Astro-physicist Avi Loeb explains what the data collected during ‘Oumuamua’s solar fly-by might teach us about other interstellar visitors.
Avi Loeb grew up on a farm outside of Tel Aviv, Israel. His earliest academic training had him leaning toward a career in philosophy, particularly the field of existentialism. Avi’s military training in the Israeli Defense Forces included physics and mathematics, subjects close enough to his love of philosophy to keep his inquisitive mind engaged. Before they were called ‘scientists’, early men of science were called ‘philosophers’ so he was okay with his course of study. Avi began to realize that philosophers spent more time generating questions than seeking answers, a revelation that found him pursuing studies in astrophysics when his hitch was done. Loeb first arrived at Princeton, New Jersey on a grant to do postgraduate work at the Institute for Advanced Study. After three years at IAS, he was encouraged to apply for a junior faculty position, eventually landing one in the astronomy department at Harvard. Many candidates turned down this same opportunity because ‘JFs’ were not usually put on the fast track toward tenured positions. Avi arrived in 1993 and received tenure three years later. He met Ofrit Liviatan on a blind date in Tel Aviv in 1997 and they were wed two years later. Living just outside of Boston, both now work at Harvard, Ofrit serving as the director of the university’s freshman seminar program.
Loeb drew a fair amount of attention from the media with his pronouncement that data gathered from ‘Oumaumau’s pass through of our Solar System pointed to it possibly being an artificially created object rather than a naturally occuring one. As soon as the term ‘extraterrestrial’ was attached, everyone in the media wanted to get a sound bite of Avi proclaiming ‘Oumuamua was a real life manifestation of the movie E.T. (or perhaps War of the Worlds). Loeb was more inclined to discuss what the data collected about this interstellar object and not ‘LGMs’ (little green men).
Avi compared the people who dismissed anomalous data about ‘Oumuamua with those who tried Galileo for heresy without bothering to look through his telescope. Galileo turned the astronomical world upside down by reporting his telescope showed the Moon to be a body not unlike the Earth with hills, valleys, and shadows cast across its surface. The church of the day decreed all celestial objects to be of ‘perfect, divine origin with the Earth at the center’. Galileo violated dogma by placing the Earth orbiting the Sun and a tribunal convicted him for it. Galileo was sentenced to house arrest only because he had friends in high places, a veritable slap on the wrist compared to others found guilty of heresy. His contemporary, Giordano Bruno, was burned at the stake for espousing similar Heliocentric (Sun-centered) views of the Solar System. Forced to recanted his problematic ‘the Earth goes around the Sun’ statement, Galileo is said to have mumbled, “But it [the Earth] does move.” A reporter asked Loeb, “So, you think you are Galileo?” Loeb insisted he was only saying ignoring observations showing ‘Oumuamau did not behave like a naturally occurring object and not considering what the data might show was akin to what had happened to Galileo. The inference that Galileo was right (and exonerated some 350 years later) may not have stuck with the sound-bite seeking press.
Much of the data collected from ‘Oumuamua’s encounter with the Sun came from satellites searching for comets and asteroids crossing the Earth’s orbit. By the time ‘Oumuamua was detected on October 19, 2017, it was already heading away from the Sun. Analysing the data collected over eleven days as it sped out of the Solar System confirmed it to be an interstellar object. In other words, it was not tied to our Solar System’s gravity field and was just passing through. It had to have originated from somewhere outside of our Solar System. Had it been a comet or small asteroid, it would have followed a precise path dictated by the pull of the Sun’s gravity. Two particular observations made ‘Oumuamua unusual: The way the Sun’s light was reflected off the body and an unexpected change in direction that took place as it left the inner Solar System. The visitor’s anomalous behavior led Loeb and his colleagues to speculate that it might not be ‘just another space rock’, but perhaps an artificially created object.
First, Loeb considered the cyclical pattern produced by the light reflecting off ‘Oumuamua.
The regular brightening and dimming indicated the object was rotating every eight hours. This implied that it had an extreme shape at least five to ten times longer than its width. Early artistic renderings wanted to show ‘Oumuamua as a slender, cigar shaped object. Most comets or asteroids have more of a spherical shape (but not necessarily ‘round’). The improbability of a naturally created exotic shape hinted at by the data was enough to make Loeb consider whether or not ‘Oumuamua had been formed naturally. The evidence Avi and his associates used to hypothesize ‘Oumuamua may be an artificial engine leaned on one of Sherlock Holmes maxims: “When you have eliminated the impossible, whatever remains, however improbable, must be the truth.”
Loeb theorized the data could also fit a disk shaped object like a lightsail. He was involved in planning a mission to send a small, lightweight probe to the closest Earth-like planet, Proxima b, orbiting the Sun’s closest neighbor, Proxima Centauri. Called the StarShot Initiative, the idea is to use a powerful laser to push a small sensor chip (called a StarChip) attached to a lightsail. To reach the planetary system within the lifetime of the program’s developers requires this combination of laser and lightsail to push the payload to one fifth the speed of light. Loeb’s previous work with lightsail technology led some to bring up the old saw: “Whoever only has a hammer will see nothing but nails.” In other words, Avi had worked on a lightsail project so he would only see a lightsail in the ‘Oumuamua data.
Is it far fetched to picture artificially created space debris passing through our Solar System? Humans have launched several craft (Voyager 1 and 2 for example) that have now departed the planetary fringe of our own system. With a probable 6 BILLION Earth-like planets in our own galaxy, it is just a tad arrogant to think there is but one that is inhabited. Perhaps we have had other artificial interstellar objects pass our way in the past but only now do we have the technology necessary to see them. There was little in the data suggesting ‘Oumaumua matched observations one would expect from a ‘normal’ comet or asteroid passing our way.
For its size and reflectivity, it would have been unusual for an object of this size to gain enough solar energy to change its orbital characteristics the way ‘Oumuamua did. The lack of any outgassing of material (as happens when icy comets near the Sun and grow a tail of material derived from the body of the comet being heated, vapourized, and expelled) pointed to an object that was not a type of comet. When astronomers began proposing other exotic blends of frozen material to account for the lack of outgassing, Loeb reminded them it was better to have the data reflect previously documented observations. When the instruments trained on ‘Oumuamua were not able to detect compounds or elements that would normally be ejected from a naturally occuring comet or asteroid, Loeb had his second bit of evidence to add to his hypothesis. Searching for a magical mixture never seen before to account for ‘Oumuoamua’s behavior stretched the data a bit far for Avi and his associates.
The last thing that spurred Loeb to consider artificial origins for ‘Oumuamua was the deviation it took away from what should have been a relatively clean, mathematically proven orbit. Certainly, outgassing from a comet can change its orbit slightly, but the random nature of the gas ejections make it a rather jerky movement. ‘Oumuamua deviated from the predicted orbit with a smooth acceleration that suggested propulsion or control. The amount of energy needed for outgassing to cause this change would have amounted to an astounding 10 percent of ‘Oumuamua’s mass (if indeed it was some sort of exotic comet). If it was some form of lightsail, the acceleration and deviation in orbit would be easier to explain. No doubt, ‘Oumuamua was a weird object that displayed enough anomalous behaviors to leave the door open a bit from the other theories put forth to explain what it was and how it acted. The data was clear, but the answer(s) may not be clear until we see other similar interstellar visitors.
Should we be spending time searching for evidence of extraterrestrial life? Loeb thinks we should be spending time and money gathering data. As mentioned previously, with six BILLION Earth-like stars in our own galaxy, it surpasses any cultural, religious, non-religious, scientific, or flat out denial of science to be arrogant enough to say, “There are no other life forms in the cosmos.” The small group of astronomers willing to even search for it are outweighed by those who choose to chase ‘safer’ topics that insure funding for their projects. Remember the stir caused when the Large Hadron Collider came online? It was designed to search for data supporting ‘supersymmetry’ (by definition: The correspondence between fermions and bosons of identical mass that is postulated to have existed during the opening moments of the big bang and that relates gravity to the other forces of nature). There were unfounded fears the LHC at CERN (the shortened version of the French name for the ‘European Council for Nuclear Research’) would open some sort of rift that would result in the destruction of the universe, which it did not do. This particle accelerator cost a little less than FIVE BILLION dollars to construct and an additional one billion dollars per year to operate. Loeb’s point in bringing up the LHC is simply this: “If the scientific consensus eventually gives up on the [supersymmetry] theory, it will do so after vast expense and generations of effort. Until we have invested similarly in the search for extraterrestrial intelligence, flat declarations about what ‘Oumuamua is and isn’t should be judged accordingly.”
The serious search for signs of extraterrestrial intelligence started on Earth in 1959 at Cornell University as the brainchild of Phillip Morrison and Giuseppe Cocconi. They reasoned the surest sign of other intelligence in the Universe would be to find interstellar broadcasts at a radio frequency of 1.42 GHz – the wavelength of neutral hydrogen. Surely any civilizations as advanced (or more advanced) as ours would understand the, “Unique, objective standard of frequency, which must be known to every observer in the universe.” Like the LHC, the Search for ExtraTerrestrial Intelligence (SETI) has yet to uncover any data suggesting they have achieved their goal. Formal funding for SETI ended in 1993 when the U.S. government gave NASA 12.26 million dollars to begin its own radio astronomy program, yet there are still other SETI programs continuing to search for the elusive ‘we are here’ signal Morrison and Cocconi suggested we should be looking for. Some of the current searches have enlisted volunteers with home computers and time on their hands to help sort through the vast amounts of data still being collected.
One of the reasons humanity is having a hard time wrapping its collective mind around an extraterrestrial origin for ‘Oumuamua comes from lack of previous experience. Loeb suggests our reactions to such a hypothesis would be much different if we had previously discovered signs of organic life on Mars several decades ago. He poses the following scenario: “And now imagine that forty years after evidence of organic life was found on Mars, a small interstellar object – highly luminous, oddly tumbling, with a 91 percent probability of being disk-shaped – passed through our solar system and, without visible outgassing, smoothly accelerated from a path that deviated from the force of the Sun’s gravity alone, with an extra push that declined inversely with distance squared? What, in this alternate reality, do you think would have been the public’s reaction to such a hypothesis?”
In Early 2021, Arizona State University Astrophysicists Steven Desch and Alan Jackson presented their own theory: ‘Oumuamua is a flat slice sheared off a planetoid elsewhere in the galaxy. It unique observations noted in the data were caused by the object being composed mostly of nitrogen ice. The pair used similar observations of other bodies known to be covered with nitrogen ice, Pluto and Triton, to show the data was similar to ‘Oumuamua’s reflectivity. The disk-like shape was attained as this piece of planetoid was whittled down by radiation much like a bar of soap becomes smaller and thinner over time.
I have no way to gauge whether or not this view is more or less probable than Loeb’s theory, but Desch and Jackson have certainly taken the path Loeb predicted most would take. Is the ASU explanation another case of bending the data to (more or less) keep ‘Oumuamua’s origins in the realm of ‘naturally occurring objects’? Perhaps.
Life as we know it on Earth requires water. Our probes to Mars have proven without a doubt there had been liquid water on the Red Planet, enough to leave behind dry river beds and layers of sediments that could only have been deposited in bodies of water. Being a little too far out from the ‘habitable zone’, the conditions needed for the liquid water necessary for organic life changed on the planet. Mars may or may not have had time to develop detectable life forms. How many of those six BILLION Earth-like planets out there might be orbiting in the Goldie Locks zone (you know, where the temperature is ‘just right’) that allows organic life to flourish on our home world? Stay tuned as the search continues.
Top Piece Video: The Ventures get to orbital velocity on this take of Telstar . . . speaking of space debris!