Could 'Oumuamua Be A Fluffy Radiation-Driven Icy Fractal From Another Star System? (syfy.com) 90
"Oumuamua, the first object ever seen passing through our solar system from interstellar space, was thought to be emitting gas like a comet to explain its weird motion," reports Syfy Wire, "but a new idea is that the comet is just very, very porous."
Astronomer Phil Plait writes: It was hard to tell what it was; it was too small, faint, and far away to get good observations, and worse, it was only seen on its way out, so it was farther from us literally every day. Then another very weird thing happened: More observations allowed a better determination of its trajectory, and it was found that it wasn't slowing down fast enough. As it moves away, the Sun's gravity pulls on it, slowing it down...but it wasn't slowing down enough. Some force was acting on it, accelerating it very slightly... A new paper has come out that might have a solution, and it's really clever. Maybe 'Oumuamua's not flat. Maybe it's fluffy... [And thus moved by the force of sunlight giving it a tiny push]
When stars are very young, they have a huge disk of material swirling around them; it's from this material that planets form. Out far from the star, where temperatures in the disk are cold, teeny tiny grains of dust and water ice can stick together in funny shapes, creating fractals... Materials made in a fractal pattern can be very porous, and in fact out in that protoplanetary disk around a young star, physical models show that objects can grow fractally until they're as big as 'Oumuamua, and have those extremely low densities needed to account for its weird behavior. So 'Oumuamua doesn't have to be a spaceship. It just has to be a snowflake! A three-dimensionally constructed phenomenally porous low-density snowflake... [T]he new paper suggests it came from a nearby star, and one that's relatively young (less than 100 million years). It formed out in the disk, and got ejected somehow, likely from a planet forming nearby giving it a boost from its gravity.
"I certainly hope we find more beasties like this one," Plait writes. "They can tell us so much about how planets form in other star systems, which is pretty hard to figure out from dozens or hundreds of light years away.
"It's a lot easier when they obligingly send bits of their building materials to us."
Astronomer Phil Plait writes: It was hard to tell what it was; it was too small, faint, and far away to get good observations, and worse, it was only seen on its way out, so it was farther from us literally every day. Then another very weird thing happened: More observations allowed a better determination of its trajectory, and it was found that it wasn't slowing down fast enough. As it moves away, the Sun's gravity pulls on it, slowing it down...but it wasn't slowing down enough. Some force was acting on it, accelerating it very slightly... A new paper has come out that might have a solution, and it's really clever. Maybe 'Oumuamua's not flat. Maybe it's fluffy... [And thus moved by the force of sunlight giving it a tiny push]
When stars are very young, they have a huge disk of material swirling around them; it's from this material that planets form. Out far from the star, where temperatures in the disk are cold, teeny tiny grains of dust and water ice can stick together in funny shapes, creating fractals... Materials made in a fractal pattern can be very porous, and in fact out in that protoplanetary disk around a young star, physical models show that objects can grow fractally until they're as big as 'Oumuamua, and have those extremely low densities needed to account for its weird behavior. So 'Oumuamua doesn't have to be a spaceship. It just has to be a snowflake! A three-dimensionally constructed phenomenally porous low-density snowflake... [T]he new paper suggests it came from a nearby star, and one that's relatively young (less than 100 million years). It formed out in the disk, and got ejected somehow, likely from a planet forming nearby giving it a boost from its gravity.
"I certainly hope we find more beasties like this one," Plait writes. "They can tell us so much about how planets form in other star systems, which is pretty hard to figure out from dozens or hundreds of light years away.
"It's a lot easier when they obligingly send bits of their building materials to us."
Very interesting (Score:4, Insightful)
I like this kind of articles, they expand my knowledge of things astronomical.
Re: Very interesting (Score:2, Troll)
Gee, if we assign it zero mass...
I suppose the round, silvery artifact that saw in the sky over South Tulsa a few years back had to have zero mass as well; otherwise it "shouldn't have been able to be there."
When you run into "shouldn't," your theories and equations are shit.
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how desperately the pedants and the autists are struggling to write this "inconvenience" into the narrative.
Which is a very reasonable thing to do. Better a small change here and there than invoking magic.
silvery artifact that saw in the sky over South Tulsa a few years back had to have zero mass as well
Source ?
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Which is a very reasonable thing to do. Better a small change here and there than invoking magic.
Or actually admitting they don't have a clue. Or they could just go with the it's aliens
https://science.slashdot.org/s... [slashdot.org]
Which is almost exactly the same thing
Re: Very interesting (Score:4, Funny)
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I like this kind of articles, they expand my knowledge of things astronomical.
I like these kinds of articles because it reminds us that words like "fluffy" can be used in any field, even astrophysics.
Spaceship (Score:2)
Um, if there is one thing it is not is a spaceship. Can we get any dumber? Where would a spaceship possibly come from? There is no system close enough to Earth. It would take hundreds of thousands of years for a spaceship to get here from anywhere.
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Re: Spaceship (Score:3, Funny)
And as we know the universe is only 6000 years old.
Re: Spaceship (Score:2)
Sarcasm mate.
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The universe was created yesterday. All your memories are implanted. You are a brain in a bottle.
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Where did the bottle come from? Who created the universe?
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Re: Spaceship (Score:2)
It's unlikely to be a spaceship but unless you've been to it and performed a detailed scientific analysis on it then you have no idea whether is or not. As for "try to build", it's not from Earth. It's not even from this solar system. Just because we couldn't build it doesn't mean anything.
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Re: Spaceship (Score:2)
Has all research on it stopped then?
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Re: You sound like a flat earther. (Score:2)
What are you talking about? What laws of physics say an object, artificial or otherwise, can't travel from one solar system to another? Heck, whatever Oumuamua is, it's an existence proof to the contrary.
Should I clarify that when we talk about the spaceship hypothesis, we're not saying we think it's an *operational* spaceship full of living aliens? A multimillion-year-old, and (duh) long-dead, spaceprobe would fit the bill too.
Is there some law of physics I'm not aware of that says it's impossible that, mi
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That's an untestable hypothesis. Until we resort to it, lets put up all the testable ones we can think of! The "fluffy crystal" thesis is testable: Can we create similar fluffy structures in zero gravity?
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The problem with the spaceship thesis is that it runs afoul the falsification principle of Science: "We don't know what it is, so lets blame the Little Green Men."
Little green men are falsifiable too. Aliens are quite likely to actually exist. Quite a few scientists believe that we are probably not the only intelligent species in the Milky Way. The idea that Oumuamua might be an artifact of some kind is very falsifiable. We could chase the thing down and take a look. We could send back photos of its surface from 10 feet away. It is only attitudes like yours that make us unlikely to ever try.
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What sucks is we didn't detect it until it was past us, and it was only about 25 million miles away at its closest point.
I'm not paranoid, but that was close!
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Just two hundred years ago they thought crossing the Atlantic in two weeks was very quick.
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Not sure if serious. According to my calculations a spaceship could get here from another star system in as little as something like 5 years. Where are you getting hundreds of thousands from? Let me see your math.
Sierpinski's Pyramid (Score:1)
Something approximating a Sierpinski Pyramid (which has zero density)?
That's 2014 MU69 (Score:2)
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it could have been flying around space (Score:2)
Mysteries, solutions, and publication. (Score:5, Insightful)
So now here we have another person taking that idea and proposing how something with those same characteristics could have a naturally occuring origin. This is what I love about watching scientists figure something out. You start with a mystery, someone proposes a mathematically consistent but kinda out there solution, others pick it apart, work with some bits while dropping others and propose a new solution. This is one of the major reasons publication is so important, so others can build off of ideas, even half baked ones.
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You are right, and you are wrong. Plenty of libraries are completely up to date on current journals. The problem is that they are often university libraries (or corporate, or private institutions, etc.). Most public civic lending libraries are not apt to have a diversity of technical and science journals. So, you can go to the public library and get frustrated by not having the journals, or you can go to the publishers' websites and be frustrated by their paywalls, or you can try to get the journal from
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So 'by working scientists for working scientists' is what you are saying? If you don't work in a scientific field then all of the mysteries of the universe must remain a mystery, huh? If you don't publish something in a way that normal people can read then you aren't really publishing at all.
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I've heard that if you email the author(s), and ask them for a copy, they are usually more than happy to email you a copy for free.
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Extraordinary claims require extraordinary evidence. How would you feel about having to email your paper to hundreds of special snowflakes who can't go through the normal channels? Maybe if you work in the same field and they know who you are it won't annoy them too much, but even then it's inconsiderate to bother them about it. I guess you could even track down where they live and knock on the door of their house begging them for a copy of their famous paper. Or just wait outside their house in the morning
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Extraordinary claims require extraordinary evidence. How would you feel about having to email your paper to hundreds of special snowflakes who can't go through the normal channels?
For clarification, "Normal channels" usually means giving large sums of money to a profitable journal in order to read details on what was often a publicly-funded study.
I would love to see some good samaritans start publishing terabytes of peer-review journals on Torrent sites. It would be much more beneficial to society.
It's melamine scum! (Score:2)
Think of the profits to be had from lassoing that "rock" and bringing it back to earth! We could close down the melamine mines forever! No one will ever have a yucky bathtub again!
Now... (Score:2)
Water though... (Score:2)
...wouldn't we have seen some out gassing if this thing were made of water when we first detected this? And isn't that precisely one of the mysteries with this thing, is that we didn't see any out gassing?
Let scienctists speak (Score:2)
Oumauamua could be an outgassing comet-like body. Or, if it is a solar sail, and outgassing, in which case any acceleration we see must be explained by photonics pressure alone. This calculation give the very low densities given in the post.
In one astronomy post web group (which is hardly a scientific survey) the original argument that Oumauamua was a solar sail were accepted as "promoting the discussion", but there were demands that early papers for the scientific community replying on arXiv were not pr
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Applause. Very well said. Your last few sentences are the kinds of sensible watchwords that should govern all thoughtful and respectable speculative communications on new and poorly resolved phenomena.
On the technical side, an outgassing comet-like body is just one of two possibilities, one model based on dissolution, the other on accretion.
The dissolution model is the "outgassing comet". It starts as a solid or semisolid construct of a certain fixed diameter, and slowly gives up internal substance. Not
slashdot is truly dead dead dead (Score:1)
Put a fork in it because this web site is so done. Look at the responses to this interesting 'special snowflake' hypothesis to explain the only interstellar object we've ever seen. Sigh. This used to be a place where at least some highly intelligent people would post. Not anymore.