First object confirmed to originate beyond solar system detected

[Swindle1984]

And it's a weird one.


http://www.newsweek.com/oumuamua-first- ... ght-717385

http://www.newsweek.com/first-visitor-o ... m=related1

https://www.cnet.com/news/asteroid-inte ... uamua-eso/



Things we know about the asteroid:

1) It's roughly cylindrical in shape and approximately 10 times longer than it is wide

2) It's rotating around its axis, and one side appears brighter than the other, causing it to 'flash' every three hours or so

3) It's red in color

4) It originated from outside the solar system, is moving too fast for the sun to capture it, and is already on its way back out of the solar system, never to return




Anyone else getting a Rendezvous With Rama vibe here?

[SpottedKitty]

1) It's roughly cylindrical in shape and approximately 10 times longer than it is wide

I haven't heard any mention of "cylindrical", although admittedly some smaller-than-planet objects have weird shapes. E.g. the asteroid Eros looks like a peanut, and comet 67P is unmistakably a rubber duck. I have come across one speculation that it might be a splinter knocked off a larger object in a total disruption collision.

2) It's rotating around its axis, and one side appears brighter than the other, causing it to 'flash' every three hours or so

Wrong way; it isn't rotating, it's tumbling. Search for the approach videos made by the NEAR Shoemaker probe to the asteroid Eros. "Rotating around its axis" isn't stable for a long thin object. The flashing is because we're seeing it side-on, then end-on; nothing to do with one side brighter than another.

3) It's red in color

Nothing unusual there. Many of the bits and pieces out beyond Neptune are sort of reddish-coloured, due to their surface chemistry being exposed to cosmic radiation for a very, very long time.

4) It originated from outside the solar system, is moving too fast for the sun to capture it, and is already on its way back out of the solar system, never to return

It's called a hyperbolic orbit — it takes very precise aiming for an object falling inwards to be captured into a stable orbit, most of the time they just go <whoosh> thataway again. It isn't even "the very first"; several comets were discovered to have hyperbolic orbits, meaning they'll never be back again, this is only the first non-comet object we've caught in the act.

Anyone else getting a Rendezvous With Rama vibe here?

Not yet; let's wait and see if there's a followup.

[Simon_Jester]

Suffice to say that if it's an alien generation ship with a hull carved out of asteroid material, it's probably one that's gone out of control and is no longer crewed, sadly.

The 'natural object' hypothesis is perfectly plausible and there is no reason to doubt it.

[Swindle1984]

Suffice to say that if it's an alien generation ship with a hull carved out of asteroid material, it's probably one that's gone out of control and is no longer crewed, sadly.

The 'natural object' hypothesis is perfectly plausible and there is no reason to doubt it.

Well, obviously the 'natural object' hypothesis is the most reasonable. There's no evidence whatsoever it's artificial.

As for the shape, I went off the description from the articles and the concept art based on known data:





If a second and third one show up, we definitely gotta check it out though.

[SpottedKitty]

It's a pity there's no way we can send a probe chasing after it to get a close look. One of the oddities I'd love to see settled is that there's absolutely no comet-like outgassing; whatever it is, it's pure rock/nickel-iron with no detectable volatiles. That says interesting things about how it formed — probably too close to its sun to hold on to any ice. In our solar system, there's a "frost line" roughly in the middle of the asteroid belt. Outside it, icy objects like comets and many of the gas giants' moons are possible; inside it (only three examples, the moons of Mars and our Moon) they're not.

[Simon_Jester]

That, or it somehow lost all the ice in some other way. Unlikely, maybe impossible.

[Swindle1984]

True, and it's been in interstellar space for roughly 40 million years, according to the scientists quoted in the article; presumably it's spent most of that time too far from a sun for ice to heat up and outgas, so it's gotta be solid rock/metal. I wonder if it isn't something that broke off and got sent flying as the result of a massive impact event.

And according to the articles, while we're pretty sure a lot of comets we've sighted are extra-solar and won't be returning, we haven't been able to confirm it beyond a doubt. This asteroid (or whatever it is) is the first object that's 100% confirmed to be from outside the solar system.

Frankly, the fact that we're not able to examine it better is just disgusting. We've had working nuclear engines since the 60's, we've had workable designs for space colonies since the 70's, and we can't even put a man on the moon again. At this point, we should be harvesting asteroids, sending manned missions to the outer system, and operating permanent bases on Luna, Mars, Ceres, etc. and building friggin' O'Neill cylinders. When something like this comes along, we should be able to say, "hey, who's closest? Tell them to go take a look."

Our priorities as a civilization are severely disappointing.

[CetaMan]

Sadly, our goals as a society tend to be "benefit ourselves and friends at everyone else's expense" Still. Remember we really didn't do any space stuff until threatened by the prospect of someone else getting it first.

[Swindle1984]

Alien Probe or Galactic Driftwood? SETI Tunes In to 'Oumuamua

It’s a long shot, but scientists are about to listen very closely for radio signals from our solar system’s first known interstellar visitor

https://www.scientificamerican.com/arti ... -oumuamua/



Ever since its discovery in mid-October as it passed by Earth already outbound from our solar system, the mysterious object dubbed ‘Oumuamua (Hawaiian for “first messenger”) has left scientists utterly perplexed. Zooming down almost perpendicularly inside Mercury’s orbit at tens of thousands of kilometers per hour—too fast for our star’s gravity to catch—‘Oumuamua appeared to have been dropped in on our solar system from some great interstellar height, picking up even more speed on a slingshot-like loop around the sun before soaring away for parts unknown. It is now already halfway to Jupiter, too far for a rendezvous mission and rapidly fading from the view of Earth’s most powerful telescopes.

Astronomers scrambling to glimpse the fading object have revealed additional oddities. ‘Oumuamua was never seen to sprout a comet-like tail after getting close to the sun, hinting it is not a relatively fresh bit of icy flotsam from the outskirts of a nearby star system. This plus its deep red coloration—which mirrors that of some cosmic-ray-bombarded objects in our solar system—suggested that ‘Oumuamua could be an asteroid from another star. Yet those same observations also indicate ‘Oumuamua might be shaped rather like a needle, up to 800 meters long and only 80 wide, spinning every seven hours and 20 minutes. That would mean it is like no asteroid ever seen before, instead resembling the collision-minimizing form favored in many designs for notional interstellar probes. What’s more, it is twirling at a rate that could tear a loosely-bound rubble pile apart. Whatever ‘Oumuamua is, it appears to be quite solid—likely composed of rock, or even metal—seemingly tailor-made to weather long journeys between stars. So far there are few if any wholly satisfactory explanations as to how such an extremely elongated solid object could naturally form, let alone endure the forces of a natural high-speed ejection from a star system—a process thought to involve a wrenching encounter with a giant planet.

These bizarre characteristics have raised eyebrows among professional practitioners of SETI, the search for extraterrestrial intelligence, who use large radio telescopes to listen for interstellar radio transmissions from other cosmic civilizations. If ‘Oumuamua is in fact artificial, the reasoning goes, it might be transmitting or at least leaking radio waves.

So far limited observations of ‘Oumuamua, using facilities such as the SETI Institute’s Allen Telescope Array, have turned up nothing. But this Wednesday at 3 p.m. Eastern time, the Breakthrough Listen project will aim the West Virgina-based 100-meter Green Bank Telescope at ‘Oumuamua for 10 hours of observations in a wide range of radio frequencies, scanning the object across its entire rotation in search of any signals. Breakthrough Listen is part of billionaire Yuri Milner’s Breakthrough Initiatives program, a collection of lavishly-funded efforts aiming to uncover evidence of life elsewhere in the universe. Other projects include Breakthrough Starshot, which intends to develop and launch interstellar probes, as well as Breakthrough Watch, which would use large telescopes to study exoplanets for signs of life.

“With our equipment at Green Bank, we can detect a signal the strength of a mobile phone coming out of this object,” Milner says. “We don’t want to be sensational in any way, and we are very realistic about the chances this is artificial, but because this is a unique situation we think mankind can afford 10 hours of observing time using the best equipment on the planet to check a low-probability hypothesis.” Besides being simply a search for signs of aliens, Breakthrough Listen’s efforts could also narrow down the possibilities for ‘Oumuamua’s composition by looking for signs of water vapor sublimating from any sun-warmed ice lurking beneath the object’s red, desiccated surface.

Avi Loeb, an astrophysicist and Breakthrough advisor at Harvard University who helped persuade Milner to pursue the observations, is similarly pessimistic about prospects for uncovering aliens. There are, he says, arguments against its artificial origins. For one thing, its estimated spin rate seems too low to create useful amounts of “artificial gravity” for anything onboard. Furthermore, ‘Oumuamua shows no sign of moving due to rocketry or other technology, instead following an orbit shaped by the gravitational force of the sun. Its speed relative to the solar system (about 20 kilometers per second) also seems rather slow for any interstellar probe, which presumably would cruise at higher speeds for faster trips between stars. But that pace aligns perfectly with those of typical nearby stars—suggesting ‘Oumuamua might be merely a piece of galactic “driftwood” washed up by celestial currents.

Then again, Loeb says, “perhaps the aliens have a mothership that travels fast and releases baby spacecraft that freely fall into planetary system on a reconnaissance mission. In such a case, we might be able to intercept a communication signal between the different spacecraft.”

Several years ago Loeb and two colleagues performed a speculative calculation estimating the interstellar abundance of ‘Oumuamua-sized space rocks based on the density of stars in the Milky Way and the vagaries of planet formation. That calculation, Loeb says, suggests the number of such space rocks is at least a hundred thousand times too low to account for ‘Oumuamua’s detection. Simply put, objects like ‘Oumuamua should be far too rare for our current telescopes to have any reasonable chance of spotting one. Newer studies gauging the odds find that for ‘Oumuamua’s detection to not be an astronomically unlikely fluke, there must be a sizeable population of such objects continuously passing through our solar system. This in turn suggests that more-capable future observatories, such as the Large Synoptic Survey Telescope, will find many more when they begin operations in the 2020s.

“Typically in astronomy we don’t see things that are rare—if we see one, that means there’s a lot more out there,” says Breakthrough Listen’s lead scientist Andrew Siemion, who is also director of the Berkeley SETI Research Center. “So, while this is most likely a natural object, if we don’t eventually see any more, that would indeed be very strange and would increase interest from a SETI perspective.”

Either way, Siemion says, “‘Oumuamua’s presence within our solar system affords Breakthrough Listen an opportunity to reach unprecedented sensitivities to possible artificial transmitters and demonstrate our ability to track nearby, fast-moving objects. Whether this object turns out to be artificial or natural, it’s a great target.”

And if, against all odds, the Green Bank Telescope detects signals from this mysterious interstellar interloper—what happens then? Breakthrough Listen’s leaders assure us they would keep no secrets. First, the team at Green Bank would immediately re-observe ‘Oumuamua to confirm the signal. Next, they would reach out to astronomers around the world who could target the object with other radio telescopes. “We quite literally have a little Rolodex just for that,” Siemion says. “And at that moment this would become public. There’s no way to keep something like this a secret, because it requires us calling everyone we can. We tend not to ‘cry wolf’ about these things.”

[Swindle1984]

Interstellar object ‘Oumuamua covered in 'thick crust of carbon-rich gunk'

Cigar-shaped body has a deep surface layer made of organic ices baked in interstellar radiation – and potentially has ice in its heart, say astronomers

https://www.theguardian.com/science/201 ... -rich-gunk



The mysterious interstellar object ‘Oumuamua that is shooting through our solar system is wrapped in a thick coating of carbon-rich gunk that built up on its cosmic travels, astronomers have found.

New observations of the cigar-shaped body found evidence for a deep surface layer that formed when organic ices – such as frozen carbon dioxide, methane and methanol – that make up the object were battered by the intense radiation that exists between the stars.

The 400-metre-long object is the first confirmed interstellar body to visit our solar system. It was spotted in October by researchers on the Pan-Starrs telescope in Hawaii after it barrelled past the sun on its way through. The name is taken from the Hawaiian word for “messenger” or “scout”.
Is ‘Oumuamua an alien spacecraft? Initial scans show no signs of technology
Read more

The deep outer crust may have formed on the body over millions or even billions of years and gives ‘Oumuamua a dark red colour, according to researchers who investigated the object with the William Herschel Telescope on La Palma in the Canary Islands and the European Southern observatory in Chile’s Atacama desert.

“This is a slowly spinning skyscraper-shaped object with a greyish-red surface crust and potentially ice in its heart,” said Michele Bannister, a planetary astronomer who worked on the observations at Queen’s University in Belfast. When carbon-rich ice is baked in interstellar radiation, it creates a layer of “organic gunk,” she added.

The coating may explain why ‘Oumuamua did not billow clouds of gas and dust when it swept past the sun earlier this year, well inside the orbit of Mercury. Most comets shed vast plumes of gas when they are heated as they swing past the sun, including comet 67P which the European Space Agency’s Rosetta mission chaperoned around the sun in 2015.

“It may well be that this object is icy inside,” said Alan Fitzsimmons, an astronomer on the team at Queen’s University. “If the surface layer is a few tens of centimetres thick, then any ice underneath would not have been heated enough by the sun, because it takes time for the heat pulse to travel through.”
Water inside moon mostly from asteroids, study suggests
Read more

The astronomers began watching ‘Oumuamua days after it was first discovered when it was more than 40 million miles away and travelling at 130,000 miles per hour. The telescopes found no signs of rocky minerals or ice on the surface, but did find evidence for the carbon-rich crust.

“This surface layer is what happens if you take comet ices and comet dust grains and bake them with high energy particles for millions or even billions of years,” said Fitzsimmons.

The researchers went on to compare the measurements of ‘Oumuamua with those taken from asteroids and comets circling in our own solar system. They found that ‘Oumuamua resembles the so-called Trojan asteroids near Jupiter, but also objects in the Kuiper belt beyond Neptune, the most distant planet in the solar system. “Our observations are very consistent with this having started life as an icy body in its own system, similar to those found in the Kuiper belt or around Jupiter,” Fitzsimmons said. Details of the work are published in the journal Nature Astronomy.

Last week, astronomers on an alien-hunting project known as Breakthrough Listen used the huge Green Bank telescope in West Virginia to monitor ‘Oumuamua for radio signals in case it happened to be a passing spacecraft, and not an interstellar asteroid after all. To date, no signs of intelligence have been found.








Is ‘Oumuamua an alien spacecraft? Initial scans show no signs of technology

Mysterious object detected hurtling through our solar system swept for radio signals, but scientists have found no evidence it is anything other than rock

https://www.theguardian.com/science/201 ... technology



The first scans for alien technology aboard a mysterious object that is barreling through the solar system have found no evidence it is the work of an intelligent civilisation.

The cigar-shaped object was spotted hurtling through the solar system in October and while astronomers suspected it was an interstellar asteroid, its curious shape led them to propose sweeping it for radio signals in case it happened to be an alien craft.

While the long, slender object may have been well suited to flying through clouds of interstellar gas at breakneck speed, as some researchers noted, the observation that the body was tumbling through space suggests any aerodynamic advantage was at best minimal.

Scientists on the Breakthrough Listen project, funded by the internet billionaire Yuri Milner, used the Green Bank telescope in West Virginia to eavesdrop on the 400m-long body named ‘Oumuamua, from the Hawaiian word for “messenger” or “scout”. The body is twice as far from Earth as the sun, but the telescope is so sensitive it could detect transmissions as weak as those produced by a mobile phone.

But on Thursday, the astronomers declared that the first observations across four bands of the radio spectrum had found no evidence that ‘Oumuamua is anything other than a long lump of space rock. Scientists on the project have released the data from the observations so anyone can study the information.

“This is a fishing expedition,” said Avi Loeb, professor of astronomy at Harvard University and an adviser to the Breakthrough Listen project. “We are most likely not to find anything, but it is worth checking steadily our fishing hooks. We will keep searching for artificial signals from ‘Oumuamua or any other interstellar object that will be discovered in the future.”

The first batch of four observations ran from 8.45pm UK time on Wednesday until 2.45am on Thursday morning and spanned a frequency range from 1 to 12 GHz. While the search for alien signals has so far found nothing in the 1.7 to 2.6GHz range, the rest of the data is still being processed.

Andrew Siemion, director of Berkeley Seti Research Center, told the Guardian that a review of all four bands observed Wednesday night had come up blank. “We don’t see anything continuously emitting from ‘Oumuamua,” he said. “We’re now digging into some of the intermittent candidates, and trying some new machine learning-based techniques we have been working on. We expect our next observation window to be scheduled for Friday or Saturday, when we should get a view of additional phases of ‘Oumuamua as it rotates.”

The interstellar asteroid was first spotted by researchers on the Pan-Starrs telescope project in Hawaii as it swept past Earth at 85 times the distance to the moon. As ‘Oumuamua sped towards the sun, it gathered speed, reaching 196,000mph. The body is moving so fast it will eventually leave the solar system completely.









The outer layer of 'organic' ices is intriguing; similar to Oort cloud objects, but still unique. Wonder what that tells us about both interstellar space and its system of origin.

[Sky Captain]

Interesting, I remember some earlier article about Oumumamua claimed it has to be single piece of rock or iron because the spin rate is fast enough to break up loose pile of dirt. Whatever it is made up it has to stay together and also resist heating to several hundred degrees without evaporating.

[SpottedKitty]

Whatever it is made up it has to stay together and also resist heating to several hundred degrees without evaporating.

Not only that; the fast hyperbolic orbit it's on means it was only close to the sun for a relatively short time. This means the pulse of sun-warmed heat travelling inwards from the surface was over more quickly than if it had been in a more conventional orbit, so the heat would disperse faster as the surface cooled again on its way back out. A longer heat pulse would have been still warming the surface when it conducted through the crust to whatever ice might be underneath. This sudden melting might not have completely disrupted the asteroid, but it would definitely have put on a spectacular show.

[Swindle1984]

Whatever it is made up it has to stay together and also resist heating to several hundred degrees without evaporating.

Not only that; the fast hyperbolic orbit it's on means it was only close to the sun for a relatively short time. This means the pulse of sun-warmed heat travelling inwards from the surface was over more quickly than if it had been in a more conventional orbit, so the heat would disperse faster as the surface cooled again on its way back out. A longer heat pulse would have been still warming the surface when it conducted through the crust to whatever ice might be underneath. This sudden melting might not have completely disrupted the asteroid, but it would definitely have put on a spectacular show.

Which means we still need to look for outgassing as it's on its way out of the system.