Follow-up observations showed it was more like an asteroid: and going too fast to be from the solar system.
‘Oumuamua is from interstellar space. It’s the first object of its kind we’ve seen.
What scientists are learning about ‘Oumuamua tells us a bit about other planetary systems, and raises intriguing new questions.
- Living in the real world
- In the news
- ‘What if?’
The idea started looking more important as we learned just how many asteroids whiz past each year.
That probably helped get systems like Pan-STARRS up and running. It’s a collection of astronomical cameras, telescopes, and computing equipment at Haleakala Observatory.
Pan-STARRS isn’t just an ‘asteroid spotter.’ Scientists use it to study objects they’ve already found, and expect it’ll help them discover variable stars in this and nearby galaxies.1
It also let them spot and study ‘Oumuamua. I’ll get back to that.
Not everyone shares my interest in what we’re learning about this wonder-filled universe. I wouldn’t expect that.
But I wouldn’t mind running into fewer who seem downright hostile to pretty much everything learned since Copernicus. And Darwin.
The latter seems particularly distressing to real-life analogs of Mr. Squibbs. He’s the ‘are you satisfied?‘ chap in that cartoon.
I’ve explained why I think using our brains doesn’t offend God. Fairly often. Basically, I figure we should seek truth and God. Also that truth, all truth, points toward God. (Catechism of the Catholic Church, 27, 31–35, 41, 74, 2500)
If we pay attention to this universe, we’ll learn things we didn’t know before. Sometimes we’ll learn that old assumptions weren’t accurate.
I like living in a world where much of the science I learned in high school is either outdated or simply wrong.
We’ve got free will, so that’s not the only option. We can try ignoring what’s new, or live in a make-believe world. (July 23, 2017)
I enjoy flights of imagination, and think they have value. But I also think dealing with reality makes more sense that denying it.
Some Catholics seem as ardently opposed to what we’ve been learning over the last few centuries as tightly-wound disciples of Ussher. I assume they’re sincere, but am sure they are wrong.
“Bizarre shape of interstellar asteroid”
Paul Rincon, BBC News (November 20, 2017)
“An asteroid that visited us from interstellar space is one of the most elongated cosmic objects known to science, a study has shown.
“Discovered on 19 October, the object’s speed and trajectory strongly suggested it originated in a planetary system around another star.
“Astronomers have been scrambling to observe the unique space rock, known as ‘Oumuamua, before it fades from view.
“Their results so far suggest it is at least 10 times longer than it is wide.
“That ratio is more extreme than that of any asteroid or comet ever observed in our Solar System….”
ʻOumuamua is ‘first’ in several categories. It’s the first ‘comet’ re-designated as an asteroid, for starters.
Folks at Haleakala Observatory figured it was a comet when the Pan-STARRS team spotted it. Assuming it was a comet made sense at the time.
ʻOumuamua was crossing the ecliptic at a steep angle, fast. Comets from the Solar System’s distant fringes do that. Asteroids, not so much.
Astronomers standardized names — designations, actually — recently. Assuming it was a comet, they called it C/2017 U1.
A ‘next step’ was getting a closer look at C/2017 U1. And confirming that it was a comet.
Communication tech has improved a lot since my youth. That makes rapid response to objects like ʻOumuamua possible.
They couldn’t find any trace of stuff around C/2017 U1. It was already closer to our sun than Mars.
If C/2017 was a comet, it would have had a coma of gas and dust. It didn’t, so it was reclassified as an asteroid and renamed A/2017 U1.
More observations showed that A/2017 U1 had been coming in really fast: around 30 kilometers a second. It had already made its closest approach to our sun, and was on its way back to the stars.
Astronomers figure ʻOumuamua was inbound at around 26.34 kilometers a second back in 1605. It was 2,300 Astronomical Units out at that point. That’s nearly a hundred times more distant than Neptune.
No known natural activity in the Solar System could give it that speed, that far out.
It didn’t come from our planetary system. More accurately, if it did — we’ll have to take a hard look at everything we’ve learned about physics since Newton’s day.
A/2017 U1 is now 1I: an object from interstellar space, the first of its kind we’ve spotted.
Folks at the International Astronomical Union haven’t finished working out a full set of rules for what to call stuff coming from outside the Solar System. I figure that’ll get fine-tuned as we learn more
The Pan-STARRS team picked 1I’s name: ʻOumuamua. It means “scout” in Hawaiian. Or maybe “messenger.” That language’s “ʻou” means “reach out for, with “mua” repeated for emphasis: since it’s the first of its kind we’ve seen.
ʻ, the first character, isn’t an apostrophe. It’s how my language’s Latin alphabet shows the phoneme ʻokina.2
(From ESO / K. Meech et al., via Sky and Telescope, used w/o permission.)
(‘Oumuamua’s brightness, measured in visible and near-infrared. Colored dots are from observations. The dotted line shows a light curve based on those observations: and assuming that ‘Oumuamua is a featureless ellipsoid, ten times as long as it is wide. The observations don’t match that ideal, so the object probably has dark and light patches. Or maybe pits and peaks.)
“Meet ‘Oumuamua, the Interstellar Cigar”
Kelly Beatty, Sky and Telescope (November 20, 2017)
“Rapid-response observations by major observatories shows that the first-known interstellar visitor is 10 times longer than it is wide.
“In Arthur C. Clarke’s 1973 science-fiction novel Rendezvous with Rama, Earthlings discover and then investigate an interstellar ‘asteroid’ that turns out to be a huge alien spaceship shaped like a long cylinder.
“Life, it seems, sometimes imitates art….”
Nobody, including Sky and Telescope’s Kelly Beatty, has said ‘Oumuamua might be a spaceship. Or anything else artificial. Not that I’ve seen or heard.
I can see how someone might imagine it’s not natural, though.
Most are lumpy, irregular. Sort of like a potato. Or, as someone said about Philae, a rubber duck.
But they’re not as long and narrow as ‘Oumuamua seems to be.
I almost immediately thought “ship” when seeing ‘Oumuamua’s length to width ratio. That’s partly because I read science fiction. Everything from the top-grade ‘hard science’ sort to delightfully improbable space opera.
I’ve also lived most of my life near Minnesota’s lake country. Not noticing small-to-mid-size watercraft around here takes doing. Some folks manage it, and that’s another topic.
No matter what pushes or pulls them, vehicles that move through water work better if we pay attention to hydrodynamics. We knew that long before someone coined the word.
Designs have changed a bit since then, but not the physical realities we deal with.
We’ve learned that if we’re interested in stability and don’t care about moving fast, we’re better off with something about as wide as it is long.
Coracles are a familiar example. Maybe not so familiar, today, in this part of the world, now that I think of it.
We’ll make boats and ships longer when we want to go faster, and think we’ve worked out ways to stay more-or-less upright. Sometimes we make mistakes.
It’s been a bit over three and a half centuries since the Vasa made its first short, and spectacularly unsuccessful, voyage. I see that pride of the Swedish navy as a good example of why executives should let engineers do their job, and that’s yet another topic.
The point is that ‘Oumuamua’s length to width ratio is about what we see in the longest of today’s large freighters. That doesn’t mean it’s artificial. When we started building spaceships we learned that the rules are different with no atmosphere.
Major puzzles include where ‘Oumuamua is from, why it’s so narrow and how it formed.
It came in from Vega’s general direction.
That star is fairly close, about 26 light-years away. Quite a few folks know about it.
That probably explains why several news outlets used Vega when describing where ‘Oumuamua came from.
Some reporters also pointed out that Vega, along with pretty much everything else in this galaxy, is moving. When ‘Oumuamua was that far away, Vega was somewhere else.
I think Kelly Beatty had the right idea, saying ‘Oumuamua came from somewhere in or near today’s constellation Lyra.
That’s assuming that it didn’t make any course corrections before astronomers noticed it. Like I said, that’s a reasonable assumption.
We still don’t know where it’s from, or how long it’s been traveling. Maybe it came directly from a young star, while the star’s planets were settling into comparatively stable orbits.
That’s probably not the case, though. What we’ve been learning about how stars form tell us that something ‘Oumuamua’s size, from a young planetary system, would be mostly volatile gasses and ice. In other words, it’d be a comet. It’s not.
Then there’s its shape. Something that long and narrow, rotating very roughly once every eight hours, wouldn’t hold together. Not if it’s like many asteroids: more like a gravel pile than a single rock.
But if it’s a single more-or-less-solid piece, explaining how it formed gets very tricky.
Someone suggested it might be a whole lot of smaller pieces, barely touching each other, strung in a line.
That won’t work, unless something other than its shape explains ‘Oumuamua’s cyclic brightening and dimming.
If ‘Oumuamua is as long and narrow as it seems, with a roughly eight-hour ‘day,’ the pieces couldn’t stay connected. What we call centrifugal force would have broken it up long ago.
The Honolulu Institute for Astronomy’s Karen Meech and other scientists have been studying ‘Oumuamua.
Many other scientists. This is a very intriguing set of puzzles.
We’ve got a pretty good idea what ‘Oumuamua is made of: the surface, anyway. Spectroscopic information, ‘Oumuamua’s color, is a pretty good match with fairly common sorts of asteroids: P- and D-type.3
Those don’t reflect much light. What they do reflect is reddish. Scientists figure their surfaces are mostly organic-rich and anhydrous silicates, and carbon.
“Organic” doesn’t mean “alive.” I’ve talked about that, vitalism and old movies, before. (September 9, 2016)
Knowing what’s on ‘Oumuamua’s surface tells us about how much light it reflects. Combining that with how its brightness varies gives us a rotation rate of very roughly eight hours and an approximate size and shape.
Like I said, its brightness varies a lot. Meech’s team figure the least-improbable shape and size is an ellipsoid about 400 meters long by maybe 50 meters wide.
That’s about a quarter-mile long, and a bit wider than the Titanic. We’ve built, and build, ships that size. But that’s not proof it’s artificial. Still, it’s an odd shape for an asteroid.
Other scientists using slightly different assumptions came up with about the same shape, but smaller: 180 by 30 by 30 meters, or 591 feet long by 98 feet across.
Or maybe it got overly close to a supernova during its long journey.
Right now we have more questions than answers.
We gathered a fair amount of data while ‘Oumuamua was near Earth: only 30,000,000 kilometers, 19,000,000 miles, away when Pan-STARRS first spotted it. And we know what direction it’s taking on its way out.
Some outfits, including Initiative for Interstellar Studies, are looking at our best options for sending a probe after it. We don’t, quite, have the technology today. Not if we want the probe to stay near ‘Oumuamua long enough for a thorough look.
A few years or decades from now? That’s hopeful. And yet again another topic.
Recapping, we’re nearly certain that ‘Oumuamua is from somewhere beyond the Solar System. We’ve got a pretty good idea of its heading as it entered and is leaving our neighborhood. Where it started out, and where it’s going? That’s another matter.
Again, I’m quite sure that it’s a natural object. I figure scientists will eventually learn a great deal about it.
And fairly ridiculous. I might as well claim that God’s decision to make a physical reality was a mistake.
Which is pretty close to what some Christians seem to believe.
There’s an element of truth in seeing “spiritual” as better than “material.” (Catechism, 330)
All of which doesn’t explain that picture of a three-eyed whatsit apparently lecturing on astronomy. Or maybe asking for directions.
It’s from a 1930s pulp science fiction magazine, most likely replete with tales heavy on imagination and casual about facts.
But let’s imagine that a probe launched a few decades from now catches up with ‘Oumuamua, sending back the first high-resolution images of the object.
Folks back on Earth see a quarter-mile long cylinder, coated with dust accumulated over uncounted ages.
A cluster of objects at one end look a great deal like rocket nozzles, each larger than the Florence Cathedral’s dome. A bowl only slightly smaller than the Astrodome sits at the end of a tower or mast near the cylinder’s midpoint.
It’s clearly artificial. Whoever built it used tech not far from what we developed just after the Industrial Age. And it is old. Very, very old indeed.
Some folks would start quirky religions around who they felt built it.
Others would call the whole thing a conspiracy, and the checkout-aisle press would have a field day.
Folks who embrace the Enlightenment’s silly side would assume that Thomas Paine was right.
I think the antics of some Christians encourage the notion that our faith will dry up and blow away in the light of whatever scientists are currently studying.
I don’t agree, but I’m a Catholic — and know something of our faith.
If I was writing a story using the idea that ‘Oumuamua is artificial, explaining its flight path might take the most work.
There aren’t any obviously-habitable worlds out in that direction. Not close, anyway.4
And that’s still another topic. An entertaining one.
I’ve seen a few level-headed discussions of how we would and should respond to extraterrestrial contact.
One was written by a scientist-monk. Another appeared in a comic strip.
“…Frankly, if you think about it, any creatures on other planets, subject to the same laws of chemistry and physics as us, made of the same kinds of atoms, with an awareness and a will recognizably like ours would be at the very least our cousins in the cosmos. They would be so similar to us in all the essentials that I don’t think you’d even have the right to call them aliens.”
(“Brother Astronomer,” Chapter Three, Would You Baptize an Extraterrestrial? — Brother Guy Consolmagno (2000))
“I been readin’ ’bout how maybe they is planets peopled by folks with ad-vanced brains. On the other hand, maybe we got the most brains…maybe our intellects is the universe’s most ad-vanced. Either way, it’s a mighty soberin’ thought.”
(Porky Pine, in Walt Kelly’s Pogo (June 20, 1959) via Wikiquote)
More, mostly how I see what we’re learning – – –
- “Finding New Worlds”
(October 13, 2017)
- “Exoplanet Frontier”
(June 30, 2017)
- “New Worlds: The Search Continues”
(June 2, 2017)
- “Looking for Life: Enceladus and Gliese 1132 b”
(April 21, 2017)
- “KIC 8462852 and Strange Stars”
(December 2, 2016)
- “Science, Faith, and Me” (November 5, 2017)
- “Labor Day SETI” (September 8, 2017)
- “Mars: Leaky Red Planet” (April 14, 2017)
- “Knowledge: Opening the Gift” (March 26, 2017)
- “SETI: What If?” (December 23, 2016)
- “Interstellar asteroid is given a name”
Paul Rincon, BBC News (November 17, 2017)
- “Tracking the first interstellar asteroid back to its home star”
Mika McKinnon, New Scientist (November 9, 2017)
- “Project Lyra: Sending a Spacecraft to 1I/’Oumuamua (former A/2017 U1), the Interstellar Asteroid”
Andreas M. Hein, Nikolaos Perakis, Kelvin F. Long, Adam Crowl, Marshall Eubanks, Robert G. Kennedy III, Richard Osborne; Physics; arXiv, Cornell University Library (November 8, 2017)
- Exoplanet and Candidate Statistics
- “NASA’s Kepler Discovers Its Smallest ‘Habitable Zone’ Planets to Date”
(April 18, 2013)
- “Kepler-22b – Comfortably Circling within the Habitable Zone”
(December 4, 2011)