Scientists have been studying what little we know about the object. Quite a few have published their results.
Two Harvard scientists looked at the data, discussed what sort of natural object ʻOumuamua might be: and said the data also suggests that maybe it’s artificial. That put ʻOumuamuaback back in the headlines.
- In the news
- Looking ahead
So is wondering whether or not other worlds exist: ones like Earth, that is.
I figure just about everyone’s noticed a sun and a moon in Earth’s sky. And stars. Lots and lots of stars.
Folks like Anaxagoras, Aristarchus of Samos and Aristotle agreed that our sun and moon exist. So did Plato, although I get the impression that he was more into metaphysics. Anaxagoras and Anaxagoras thought other worlds might exist, and that the stars might be other suns.
Aristotle’s cosmology was more along Plato’s line. He figured everything from our moon outward is aether, while we’re stuck with earth, water, air and fire. Aristotle’s physics and cosmology made sense, given what he knew.
Aristotle had an enthusiastic fan base among European scholars, about a millennium back. I’ll get back to that.
Then 19th century science upset more applecarts. Sound and fury over reality checks was moving away from astronomy, and that’s another topic.
Astronomers were eagerly using new and better telescopes. Many non-scientists were learning what they could about recent discoveries. That interest made reports of extraterrestrial life newsworthy.
The Sun, a New York City newspaper, published a six-part series on Sir John Herschel’s “Great Astronomical Discoveries” in 1835.
The famous astronomer’s observations of Lunar life became international news.
Sir John Herschel was real. The beyond-cutting-edge telescope and incredibly detailed observations weren’t. Neither were The Sun’s bat-winged Lunarians. Lunarites??
The Sun became one of New York City’s top newspapers. We still don’t know who wrote the ersatz articles. (December 16, 2016)
And we still don’t know if there’s life on — or in — other worlds. But we’re learning.
Photosynthetic organisms like plants get energy directly from sunlight.
Critters that don’t use sunlight directly get energy by consuming other organisms. The other organisms in turn use energy which started as sunlight.
Life apparently couldn’t exist unless sunlight was providing energy. Even critters living deep under water or in caves get energy from other critters — and, somewhere along the line, sunlight.
Meanwhile, a few scientists were studying hot water in the Red Sea.
By the time I finished high school, they’d learned that it contained traces of toxic metals. The hotspots were interesting to geologists and geochemists, but not biologists. Nothing could survive there. We thought.
Scientists found other hotspots in the Pacific’s Galápagos Rift, a spur of the East Pacific Rise in 1976. A probe sent down in 1977 detected living critters around the Galápagos Rift’s hotspots. Lots of critters.
Scientists figured that critters living around hydrothermal vents got their energy the way everything else does: from sunlight.
Not directly, since little sunlight reaches more than about 200 meters down, and none below the ocean’s top kilometer. Below that, critters get their energy by eating “marine snow,” bits and pieces that didn’t get eaten in the sunlit regions.
Critters living around hydrothermal vents get some energy from the marine snow. But they’re mostly powered by what’s pouring out of the vent. They’re thriving in conditions that’d kill us.1
If extraterrestrial life existed at all, scientists figured it would be on a planet like Earth. That narrowed the field to Venus and Mars.
Venus is nearly as massive as Earth, and almost far enough from our star for water to be a liquid. Seasonal changes on Mars looked a little like Earth’s spring-summer-autumn-winter vegetation cycle. The Solar System’s fourth planet even has polar caps.
Some science fiction writers didn’t use all that much science in their tales. Some did. Both sorts often assumed that their alien life would be on places like Earth.
Others looked outside the box. A few suggested scientifically-plausible alien life on worlds that weren’t much like ours. Or life that barely noticed planets, like Fred Hoyle’s “The Black Cloud.”
One of Boston University’s biochemistry professors, Isaac Asmiov, was making more money as a writer than a professor by the mid-1950s. That may explain why he discussed several alternative life chemistry as science, not fiction:
- Fluorosilicone in fluorosilicone
- Fluorocarbon in sulfur
- Nucleic acid/protein (O) in water
- Nucleic acid/protein (N) in ammonia
- Lipid in methane
- Lipid in hydrogen
(“View from a Height” Isaac Asimov (1963), Lancer Books (p. 63))
We’re third from the top in that list, nucleic acid/protein (O) in water.
Granted, his 1963 “View From a Height” was a collection of popular-science essays, not a professional research paper. But this was back when hypothetical biochemistry was “science fiction,” like Tenebrites in Hal Clement’s 1958 “Close to Critical.”
In 1976, Viking 1 became the first probe to survive landing on Mars and complete its mission. The lander’s experiments provided a Martian soil sample with near-ideal conditions for microbes. Terrestrial microbes.
Scientists eventually decided that odd chemistry, not life, produced the weird results they’d seen. Most scientists. Maybe the original majority opinion was right. Or maybe Martian life doesn’t act just like what’s in Terrestrial topsoil.
I suspect that some non-Terrestrial biochemistries, like those using hydrogen fluoride instead of water, are few and far between. If they exist at all.
This universe is well-stocked with stuff like water, ammonia and methane; and the hydrogen, oxygen, carbon or nitrogen they’re made from.
Fluorine isn’t as rare as, say, bismuth. But it’s not common either.
I’m not sure how we’d look for life that uses hydrogen fluoride as its default solvent. The last I checked, we’re still trying to settle on a definition for “life.”2
I could say that a physical entity sending and receiving signals and sustaining itself is alive. Living things do that.
So do some of our robots, particularly those we send to explore other worlds. They’re not very good at sustaining themselves, but neither are some “living” critters. That doesn’t mean I think robots are “alive.”
Antics by a few folks who act as if our faith demands profound ignorance and rejection of pretty much everything learned since the early 19th century don’t help. My opinion.
Not that most folks before 1800 thought Earth is flat. Certainly not those who had been paying any attention to post-Mesoptamian developments.
Natural philosophers like Aristotle and Anaxagoras figured out that Earth is spherical, or nearly so.
They didn’t agree on how this universe works, which brings me to European scholars, about a millennium back.
Whether or not we’re standing on the only world in this universe became a lively issue. Some said maybe other worlds exist. Others said maybe not. Some said other worlds couldn’t exist, and that Earth must be the only one. Because Aristotle had said so.
That’s when the Church stepped in. Proposition 27/219 of 1277 has been rescinded, but the principle still holds. Agreeing with Aristotle can be okay. Saying God must agree with Aristotle, or anyone else, is a bad idea. And, I think, just a bit daft.
God is large and in charge, and runs this universe. (Catechism of the Catholic Church, 268)
That’s not a new idea:
“Our God is in heaven; whatever God wills is done.”
We’ve learned that Aristarchus was on the right track. Other worlds exist. Some are enough like Earth to let us think maybe they support life. I won’t say that life must have emerged on other worlds, or that it mustn’t. I hope it did, but it’s not my decision.
We may even hit the jackpot: finding extraterrestrial life that’s smart, sociable and interested in meeting new neighbors. Or maybe they found us in 2017.
“Scientists say mysterious ‘Oumuamua’ object could be an alien spacecraft”
David Freeman, NBC News (November 5, 2018)
“Now a pair of Harvard researchers are raising the possibility that Oumuamua is an alien spacecraft. As they say in a paper to be published Nov. 12 in The Astrophysical Journal Letters, the object ‘may be a fully operational probe sent intentionally to Earth vicinity by an alien civilization.’
“The researchers aren’t claiming outright that aliens sent Oumuamua. But after a careful mathematical analysis of the way the interstellar object sped up as it shot past the sun, they say Oumuamua could be a spacecraft pushed through space by light falling on its surface — or, as they put it in the paper, a ‘lightsail of artificial origin.’
“Who would have sent such a spacecraft our way — and why?
“‘It is impossible to guess the purpose behind Oumuamua without more data,’ Avi Loeb, chairman of Harvard’s astronomy department and a co-author of the paper, told NBC News MACH in an email. If Oumuamua is a lightsail, he added, one possibility is that it was floating in interstellar space when our solar system ran into it, ‘like a ship bumping into a buoy on the surface of the ocean.’…”
I’m writing this before the Harvard paper gets published. All I know about it is what’s been in the news. And what I can guess, after a little research.
Abraham (Avi) Loeb and Shmuel Bialy wrote about “‘Oumuamua’s Peculiar Acceleration” earlier this year. So have other scientists.
The acceleration wouldn’t be “peculiar,” if ‘Oumuamua was a comet.
Comets warm up as they pass near our star, releasing frozen gasses and dust. That stuff, streaming out from the comet’s nucleus, produces more-or-less spectacular tails — and a little thrust. Not much, but enough to give the comet a little nudge.
‘Oumuamua’s acceleration was about as much as we’d expect from a comet, and consistent with what we’d see when frozen gasses evaporated on the object’s surface.
There’s just one problem with that scenario. From what I’ve read so far, we haven’t seen gasses coming from ‘Oumuamua.
Something other than our star’s gravity gave ‘Oumuamua a little nudge.
Maybe it was gas that didn’t get detected.
Maybe ‘Oumuamua is much darker than we figured. That’d make it much larger than estimated, which might help explain the unexpected acceleration.
Estimates of its size and shape are based on how much light it reflected as it passed our star, and the qualities of that light. It could be covered in something the same ‘color’ as dusty asteroids, but a whole lot darker.
If that’s the case, we’ve got more puzzles to solve: including what the unknown stuff is.
Maybe ‘Oumuamua is a flyby probe and deployed a light sail.3 Or maybe it uses a propulsion technology we haven’t developed yet.
Judging from the headlines, some of the ‘alien probe’ pieces could have been written for supermarket tabloids.
I’d enjoy that sort of journalism more, maybe, if it was packaged as fiction. Or if more folks realized that astronomy isn’t astrology, and that’s yet another topic. (September 29, 2017)
“‘Aliens’ Is Not A Scientific Explanation For Interstellar Asteroid ʻOumuamua”
Ethan Siegel, Forbes (November 8, 2018)
“…According to a new paper by Harvard scientists Schmuel Baily and Avi Loeb, it could have been due to an alien-created lightsail from a distant, extraterrestrial civilization. Although the idea has taken the world by storm, it’s a shocking example of sensationalist, ill-motivated science….
I think the Forbes science writer has a point. We don’t know for sure what ʻOumuamua is.
It’s about the color of many asteroids. That, and its path through the inner Solar System, strongly suggests that it may be an asteroid that formed near another star.
If ʻOumuamua is as long and narrow as scientists think it is, it’s the longest and narrowest asteroid we’ve spotted so far. Scientists may find a natural process that caused its odd acceleration.
ʻOumuamua could be nothing more than an asteroid that just happens to be long and narrow. Maybe it picked up more speed by an as-yet-unknown but natural process.
But I’m not convinced that the paper being published next week is “sensationalist, ill-motivated science.”
The ʻOumuamua paper’s submission for publication near the anniversary of ʻOumuamua’s discovery suggests that the scientists may have publicity and funding for their department in mind. I don’t think that makes their research invalid. Just well-timed.
I suppose the Harvard scientists might have said that ʻOumuamua couldn’t possibly be artificial, because it’s a new idea. Perhaps that would seem more ‘scientific,’ at least in some circles.
There’s nothing remarkable about KIC 8462852, except for one thing. It flickers. One of the simpler explanations is that something comes between it and the Solar System. Two dips in brightness come at roughly 750-day intervals. Others aren’t regular.
Scientists figure whatever’s orbiting KIC 8462852 is a clumpy dust ring. Or a bunch of disintegrating comets. Or the star is younger than we thought, and there’s still stuff falling into it. Or it’s debris from a planetary collision. Or it’s something else.
A few scientists have said that whatever’s getting between us and the star is probably a natural object. Or objects. But since observations don’t quite match the ‘natural object’ explanations: maybe it’s not natural. Let’s consider the possibility that it’s artificial. (December 2, 2016)
That attitude makes more sense to me than assuming that scientists knew all there is to know when I was young. Or that extraterrestrial intelligence can’t exist because we don’t know about it yet.
I’ll grant that the Harvard scientists say that maybe ‘Oumuamua is artificial. In one cautiously-worded paragraph, after discussing more familiar assumptions.
“…Alternatively, a more exotic scenario is that ‘Oumuamua may be a fully operational probe sent intentionally to Earth vicinity by an alien civilization….”
(Shmuel Bialy, Abraham Loeb; The Astrophysical Journal Letters (Submitted October 26, 2018; Revised October 30, 2018))
I don’t think what they wrote about that possibility is “sensationalist, ill-motivated science.”
‘Oumuamua didn’t get close enough to Earth for anyone to get a clear image of the object. We did, however, get a good look at what little light was reflecting off its surface. It’s a pretty good match to what we’ve seen reflected from P- and D-type asteroids.
The object’s brightness changed considerably during a roughly eight-hour cycle. A simple explanation is that it’s rotating and longer than it is wide. A lot longer. The odds are pretty good that it’s about the size and shape of a largeish container ship.
If it’s a natural body, like an asteroid, that shape raises questions about its nature and origin. If someone built it, that raises other questions.
The possibility that ‘Oumuamua is artificial encouraged scientists to point radio telescopes at the Allen Telescope Array and Green Bank toward the object. They ‘heard’ nothing, but still ‘listen’ occasionally.
I figure that means ‘Oumuamua is a natural object: an oddly-shaped asteroid that formed near another star. Or maybe it’s artificial, but wasn’t transmitting while the radio telescopes were pointed toward it. Or was transmitting, but not on one of the channels the scientists checked.
I don’t believe ‘Oumuamua that is natural or artificial. Right now, that’s something we don’t know.
But playing with the notion that ‘Oumuamua is an alien probe is fun, so I’ll let my imagination work on what little we know about it.
A team of scientists narrowed the less-unlikely origins to four stars, some of them not much more than 100 light-years away.
One, HD 292249, is a bit like our sun; but doesn’t have any planets. None that we’ve spotted yet, that is.4
If ‘Oumuamua has been between stars for millions of years, that could explain why it’s the color of some asteroids. In unscientific terms, it’s gotten dusty.
Or maybe whoever built it wanted it to look like an asteroid at first glance. Which makes its shape downright hard to explain. Maybe some of their tech won’t work otherwise.
That might explain its size, too. We’re newbies. Our oldest spaceships are no more than a few decades old. Our probes aren’t particularly big, mostly because we’re doing well to get something the size of a grand piano into the outer Solar System.
Compared to our interplanetary probes, ‘Oumuamua is huge. But maybe, to folks who have been around a little longer, something the size of a container ship fits nicely into a survey vessel’s multiple launch system.
Or, perhaps more likely, ‘Oumuamua is a natural object.
Or that we’re the only people living in this vast cosmos.
Either way, it’s not up to me. God’s God, I’m not, and that’s okay.
If we do meet folks who are not human, my guess is that we’ll be in for some surprises. Big ones. Some of us won’t like it.
But we got over the shock of learning that Aristotle wasn’t all-knowing. I figure we’ll deal with whatever we find during the next millennium. And, if we learn that we have neighbors, whoever we meet.
And we still won’t have all the answers. But I’m quite certain that we’ll keep looking for life in this universe, and learning more in the process. This is a good thing:
- “Oxygen, Alien Life”
(February 23, 2018)
- “Visitor from the Stars”
(November 24, 2017)
- “Finding New Worlds”
(October 13, 2017)
- “SETI: What If?”
(December 23, 2016)
- “KIC 8462852 and Strange Stars”
(December 2, 2016)
- “Could Solar Radiation Pressure Explain ‘Oumuamua’s Peculiar Acceleration?”
Shmuel Bialy, Abraham Loeb; The Astrophysical Journal Letters (Submitted October 26, 2018; Revised October 30, 2018) via arXiv
- Professor Avi Loeb
Center for Astrophysics, Harvard
- Professor Avi Loeb
- “Our Solar System’s First Known Interstellar Object Gets Unexpected Speed Boost”
Calla Cofield, JPL; Felicia Chou/JoAnna Wendel, NASA; Donna Weaver/Ray Villard, Space Telescope Science Institute, Baltimore; JPL/NASA News (June 27, 2018)
- “‘Oumuamua Isn’t from Our Solar System. Now We May Know Which Star It Came From”
Meghan Bartels, Space.com (September 25, 2018)
- “Plausible home stars of the interstellar object ‘Oumuamua found in Gaia DR2”
C.A.L. Bailer-Jones (MPIA Heidelberg), D. Farnocchia (JPL), K.J. Meech (Uni. Hawai’i), R. Brasser (Tokyo Institute of Technology), M. Micheli (ESA SSA-NEO Coordination Centre), S. Chakrabarti (Rochester Institute of Technology), M.W. Buie (Southwest Research Institute), O.R. Hainaut (ESO); The Astrophysical Journal Letters (Submitted September 24, 2018) via arXiv
- SIMBAD Astronomical Database