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General => Science => Topic started by: Recusant on October 28, 2017, 05:21:38 AM

Title: First Observation of an Interstellar Visitor
Post by: Recusant on October 28, 2017, 05:21:38 AM
Sorry, it's not a UFO.  :)

"Astronomers capture first visiting object from outside our solar system" | PhysOrg (https://phys.org/news/2017-10-astronomers-capture-solar.html)

Quote
(https://3c1703fe8d.site.internapcdn.net/newman/csz/news/800/2017/59f387b458cb2.jpg)
Image credit: Queen's University Belfast

A Queen's University Belfast scientist is leading an international team in studying a new visitor to our solar system - the first known comet or asteroid to visit us from another star.

The fast-moving object, now named A/2017 U1, was initially spotted on 18 October in Hawaii by the Pan-STARRS 1 telescope in Hawaii. Professor Alan Fitzsimmons from the School of Mathematics and Physics at Queen's, together with colleagues in the UK, USA and Chile have been tracking it using powerful telescopes across the world.

Commenting on the project, Professor Fitzsimmons said: "By Wednesday this week it became almost certain this object was alien to our solar system. We immediately started studying it that night with the William Herschel Telescope in the Canary Islands, then on Thursday night with the Very Large Telescope in Chile."

The initial data implies it is a small rocky or icy object that may have been drifting through our galaxy for millions or even billions of years, before entering our solar system by chance. The object flew into the solar system from above, was close to the Sun last month, and is now already on its way back out to the stars.

Astronomers believe it was probably thrown out of another star system during a period of planet formation. The same process is thought to have unfolded 4.5 billion years ago around our own star, when Jupiter and Saturn formed. Despite suspecting such objects existed and looking out for them over past decades, scientists have never seen such an interstellar visitor until now.


[Continues . . . (https://phys.org/news/2017-10-astronomers-capture-solar.html#jCp)]

Space.com has a nice animation of the path of A/2017 U1, but the page takes a long time to load.

"Visitor from Far, Far Away: Interstellar Object Spotted in Our Solar System" | Space.com (https://www.space.com/38580-interstellar-object-spotted-comet-asteroid-mystery.html)
Title: Re: First Observation of an Interstellar Visitor
Post by: Tank on October 28, 2017, 08:13:22 AM
Wow!!!
Title: Re: First Observation of an Interstellar Visitor
Post by: OldGit on October 28, 2017, 02:25:47 PM
I bet it doesn't have the proper documents and visas.
Title: Re: First Observation of an Interstellar Visitor
Post by: joeactor on October 28, 2017, 04:07:26 PM
Quote from: OldGit on October 28, 2017, 02:25:47 PM
I bet it doesn't have the proper documents and visas.

Ha!

Amazing that they were able to observe it, though...
Title: Re: First Observation of an Interstellar Visitor
Post by: Bad Penny II on October 28, 2017, 04:21:43 PM
North Korean
Title: Re: First Observation of an Interstellar Visitor
Post by: No one on October 29, 2017, 07:44:54 PM
(https://www.happyatheistforum.com/forum/proxy.php?request=http%3A%2F%2Fwww.trackie.com%2Ftrack-and-field%2Fimg%2Flayout%2Ficon_quote.jpg&hash=c5a9d5ac5c9c0366d813e18a50510fe9aa16bfc2)Recusant:
Sorry, it's not a UFO.

And here I was hoping it was the mothership coming to take the trumpster back to planet Blockhead. (https://web.stardock.net/images/smiles/themes/digicons/Mad.png)
Title: Re: First Observation of an Interstellar Visitor
Post by: Magdalena on October 30, 2017, 03:20:53 AM
Quote from: No one on October 29, 2017, 07:44:54 PM
(https://www.happyatheistforum.com/forum/proxy.php?request=http%3A%2F%2Fwww.trackie.com%2Ftrack-and-field%2Fimg%2Flayout%2Ficon_quote.jpg&hash=c5a9d5ac5c9c0366d813e18a50510fe9aa16bfc2)Recusant:
Sorry, it's not a UFO.

And here I was hoping it was the mothership coming to take the trumpster back to planet Blockhead. (https://web.stardock.net/images/smiles/themes/digicons/Mad.png)
:therethere:
Soon my child--soon. 
Title: Re: First Observation of an Interstellar Visitor
Post by: xSilverPhinx on October 30, 2017, 11:38:43 PM
Quote from: OldGit on October 28, 2017, 02:25:47 PM
I bet it doesn't have the proper documents and visas.

:lol:
Title: Re: First Observation of an Interstellar Visitor
Post by: Recusant on November 29, 2017, 03:21:08 AM
A little more about this object:

"ESO Observations Show First Interstellar Asteroid is Like Nothing Seen Before" | European Southern Observatory (http://www.eso.org/public/news/eso1737/#.WhMNSshnQNM.)

Quote
(https://cdn.eso.org/images/thumb700x/eso1737a.jpg)
Artist's impression of `Oumuamua
Image Credit: ESO/M. Kornmesser


For the first time ever astronomers have studied an asteroid that has entered the Solar System from interstellar space. Observations from ESO's Very Large Telescope in Chile and other observatories around the world show that this unique object was traveling through space for millions of years before its chance encounter with our star system. It appears to be a dark, reddish, highly-elongated rocky or high-metal-content object.

On 19 October 2017, the Pan-STARRS 1 telescope in Hawai`i picked up a faint point of light moving across the sky. It initially looked like a typical fast-moving small asteroid, but additional observations over the next couple of days allowed its orbit to be computed fairly accurately. The orbit calculations revealed beyond any doubt that this body did not originate from inside the Solar System, like all other asteroids or comets ever observed, but instead had come from interstellar space. Although originally classified as a comet, observations from ESO and elsewhere revealed no signs of cometary activity after it passed closest to the Sun in September 2017. The object was reclassified as an interstellar asteroid and named 1I/2017 U1 (`Oumuamua).

"We had to act quickly," explains team member Olivier Hainaut from ESO in Garching, Germany. "`Oumuamua had already passed its closest point to the Sun and was heading back into interstellar space."

ESO's Very Large Telescope was immediately called into action to measure the object's orbit, brightness and colour more accurately than smaller telescopes could achieve. Speed was vital as `Oumuamua was rapidly fading as it headed away from the Sun and past the Earth's orbit, on its way out of the Solar System. There were more surprises to come.

Combining the images from the FORS instrument on the VLT using four different filters with those of other large telescopes, the team of astronomers led by Karen Meech (Institute for Astronomy, Hawai`i, USA) found that `Oumuamua varies dramatically in brightness by a factor of ten as it spins on its axis every 7.3 hours.

Karen Meech explains the significance: "This unusually large variation in brightness means that the object is highly elongated: about ten times as long as it is wide, with a complex, convoluted shape. We also found that it has a dark red colour, similar to objects in the outer Solar System, and confirmed that it is completely inert, without the faintest hint of dust around it."

These properties suggest that `Oumuamua is dense, possibly rocky or with high metal content, lacks significant amounts of water or ice, and that its surface is now dark and reddened due to the effects of irradiation from cosmic rays over millions of years. It is estimated to be at least 400 metres long.

Preliminary orbital calculations suggested that the object had come from the approximate direction of the bright star Vega, in the northern constellation of Lyra. However, even travelling at a breakneck speed of about 95 000 kilometres/hour, it took so long for the interstellar object to make the journey to our Solar System that Vega was not near that position when the asteroid was there about 300 000 years ago. `Oumuamua may well have been wandering through the Milky Way, unattached to any star system, for hundreds of millions of years before its chance encounter with the Solar System.

[Continues . . . (http://www.eso.org/public/news/eso1737/#.WhMNSshnQNM.)]
Title: Re: First Observation of an Interstellar Visitor
Post by: Davin on November 29, 2017, 01:50:53 PM
It's OK, we still have humpback whales.
Title: Re: First Observation of an Interstellar Visitor
Post by: Bad Penny II on November 29, 2017, 01:54:50 PM
Quote from: Davin on November 29, 2017, 01:50:53 PM
It's OK, we still have humpback whales.

Ye I think we'll be OK, Japan though..
http://www.abc.net.au/news/2017-11-28/video-of-whaling-in-southern-ocean-released-by-sea-shepherd/9198446 (http://www.abc.net.au/news/2017-11-28/video-of-whaling-in-southern-ocean-released-by-sea-shepherd/9198446)
Title: Re: First Observation of an Interstellar Visitor
Post by: Recusant on December 12, 2017, 06:54:18 AM
They're going to just check that 'Oumuamua isn't sending out any radio signals.

"Alien Probe or Galactic Driftwood? SETI Tunes In to 'Oumuamua" | Scientific American (https://www.scientificamerican.com/article/alien-probe-or-galactic-driftwood-seti-tunes-in-to-oumuamua/)

QuoteSo 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.

[Continues . . . (https://www.scientificamerican.com/article/alien-probe-or-galactic-driftwood-seti-tunes-in-to-oumuamua/)]
Title: Re: First Observation of an Interstellar Visitor
Post by: AngelOfDeath on December 12, 2017, 07:10:14 AM
alien craft or POS space rock?
Title: Re: First Observation of an Interstellar Visitor
Post by: Tank on December 12, 2017, 09:05:43 AM
Quote from: AngelOfDeath on December 12, 2017, 07:10:14 AM
alien craft or POS space rock?

Wouldn't it be a kick in the teeth if it was an alien space craft. I can just see the headlines.

Aliens visit and fuck off without stopping!!!
Title: Re: First Observation of an Interstellar Visitor
Post by: OldGit on December 12, 2017, 09:58:46 AM
They took one good look at this place and said 'bugger that!'
Title: Re: First Observation of an Interstellar Visitor
Post by: Tank on December 12, 2017, 10:06:02 AM
Quote from: OldGit on December 12, 2017, 09:58:46 AM
They took one good look at this place and said 'bugger that!'
Exactly!
Title: Re: First Observation of an Interstellar Visitor
Post by: AngelOfDeath on December 12, 2017, 05:41:16 PM

oh yea.  the ultimate cold shoulder  ;D
Title: Re: First Observation of an Interstellar Visitor
Post by: Recusant on December 20, 2017, 04:41:56 AM
Apparently not a peep was heard (https://phys.org/news/2017-12-alien-cigar-shaped-asteroid.html#nRlv) from `Oumuamua.

QuoteNo alien signals have been detected from an interstellar, cigar-shaped space rock discovered travelling through our Solar System in October, researchers listening for evidence of extraterrestrial technology said Thursday.

The object, dubbed Oumuamua, was spotted by several Earthly telescopes two months ago.

Given its weird trajectory, surprised researchers immediately concluded it was from beyond our planetary system—the first interstellar object ever identified in our midst.

The rock is thought to be about 400 metres (1,300 feet) long, and thin—only about 40 m wide, a never-before-seen shape for an asteroid.

After its discovery was announced last month, a project called Breakthrough Listen, dedicated to finding signs of extraterrestrial intelligence, said it would study the rock for artificial signals.

"No such signals have been detected" by its network of telescopes, the project said Thursday, adding: "the analysis is not yet complete".

[Continues . . . (https://phys.org/news/2017-12-alien-cigar-shaped-asteroid.html#jCp)]

Its surface appearance is a fairly close match to objects found in our own solar system.

"Alien object 'Oumuama was a natural body visiting from another solar system" | PhysOrg (https://phys.org/news/2017-12-alien-oumuama-natural-body-solar.html)

QuoteScientists at Queen's University Belfast have led worldwide investigations into a mysterious object that passed close to Earth after arriving from deep interstellar space.Since the object was spotted in October, Professor Alan Fitzsimmons and Dr Michele Bannister from the School of Mathematics and Physics at Queen's University have led an international team of astronomers to piece together a profile of the strange visitor, which has been named `Oumuamua.

The team was made up of researchers from elsewhere in the UK, the US, Canada, Taiwan and Chile and in total seven researchers from Queen's were involved.

Professor Alan Fitzsimmons headed up a team which measured the way that `Oumuamua, reflects sunlight, and found it similar to icy objects covered with a dry crust. This is because `Oumuamua has been exposed to cosmic rays for millions, or even billions, of years, creating an insulating organic-rich layer on its surface.

The research, which has been published this week in Nature Astronomy, suggests that `Oumuamua's dry crust could have protected its icy interior from being vaporised - even though the object was just 23 million miles from our sun in September when it zipped past.

Professor Alan Fitzsimmons commented: "We have discovered that the surface of `Oumuamua is similar to small solar system bodies that are covered in carbon-rich ices, whose structure is modified by exposure to cosmic rays.

"We have also found that a half-metre thick coating of organic-rich material could have protected a water-ice-rich comet-like interior from vaporizing when the object was heated by the sun, even though it was heated to over 300 degrees centigrade."

[Continues . . . (https://phys.org/news/2017-12-alien-oumuama-natural-body-solar.html)]

Title: Re: First Observation of an Interstellar Visitor
Post by: Magdalena on December 20, 2017, 06:03:09 AM
Quote from: Recusant on December 20, 2017, 04:41:56 AM
Apparently not a peep was heard (https://phys.org/news/2017-12-alien-cigar-shaped-asteroid.html#nRlv) from `Oumuamua.
...
(https://gifrific.com/wp-content/uploads/2013/03/Tony-Stark-Shakes-Head-Iron-Man.gif)
Title: Re: First Observation of an Interstellar Visitor
Post by: xSilverPhinx on December 20, 2017, 10:02:06 PM
Quote from: Magdalena on December 20, 2017, 06:03:09 AM
Quote from: Recusant on December 20, 2017, 04:41:56 AM
Apparently not a peep was heard (https://phys.org/news/2017-12-alien-cigar-shaped-asteroid.html#nRlv) from `Oumuamua.
...
(https://gifrific.com/wp-content/uploads/2013/03/Tony-Stark-Shakes-Head-Iron-Man.gif)

Don't lose hope. :therethere: The Mothership will come to take Trump home.

:P
Title: Re: First Observation of an Interstellar Visitor
Post by: Magdalena on December 20, 2017, 10:04:37 PM
Quote from: xSilverPhinx on December 20, 2017, 10:02:06 PM
Quote from: Magdalena on December 20, 2017, 06:03:09 AM
Quote from: Recusant on December 20, 2017, 04:41:56 AM
Apparently not a peep was heard (https://phys.org/news/2017-12-alien-cigar-shaped-asteroid.html#nRlv) from `Oumuamua.
...
(https://gifrific.com/wp-content/uploads/2013/03/Tony-Stark-Shakes-Head-Iron-Man.gif)

Don't lose hope. :therethere: The Mothership will come to take Trump home.

:P

:lol:
Title: Re: First Observation of an Interstellar Visitor
Post by: Recusant on January 25, 2018, 12:59:20 AM
A summation of current knowledge about 'Oumuamua; the only newish thing I noticed is the note on a paper (http://iopscience.iop.org/article/10.3847/2515-5172/aaa02b/meta) arguing that this observation implies that there is a very large number of these interstellar objects rattling around the galaxy.

'Update on an Interstellar Asteroid' (http://aasnova.org/2018/01/19/update-on-an-interstellar-asteroid/)

QuoteSince 'Oumuamua's discovery, scientists have been gathering as many observations of this body as possible before it vanishes into the distance. Simultaneously, theorists have leapt at the opportunity to explain its presence and the implications its passage has on our understanding of our surroundings. Here we present just a few of the latest studies that have been published on this first detected interstellar asteroid — including several timely studies published in our new journal, Research Notes of the AAS (http://iopscience.iop.org/journal/2515-5172).

[Continues . . . (http://aasnova.org/2018/01/19/update-on-an-interstellar-asteroid/)]
Title: Re: First Observation of an Interstellar Visitor
Post by: Recusant on June 15, 2018, 01:04:30 AM
A visitor that apparently came and stayed:

"First interstellar immigrant discovered in the solar system" | ScienceDaily (https://www.sciencedaily.com/releases/2018/05/180521092717.htm)

QuoteA new study has discovered the first known permanent immigrant to our Solar System. The asteroid, currently nestling in Jupiter's orbit, is the first known asteroid to have been captured from another star system. The work is published in Monthly Notices of the Royal Astronomical Society: Letters.

The object known as 'Oumuamua was the last interstellar interloper to hit the headlines in 2017. However it was just a tourist passing through, whereas this former exo-asteroid - given the catchy name (514107) 2015 BZ509 - is a long-term resident.

All of the planets in our Solar System, and the vast majority of other objects as well, travel around the Sun in the same direction. However 2015 BZ509 is different - it moves in the opposite direction in what is known as a 'retrograde' orbit.

"How the asteroid came to move in this way while sharing Jupiter's orbit has until now been a mystery," explains Dr Fathi Namouni, lead author of the study. "If 2015 BZ509 were a native of our system, it should have had the same original direction as all of the other planets and asteroids, inherited from the cloud of gas and dust that formed them."

However the team ran simulations to trace the location of 2015 BZ509 right back to the birth of our Solar System, 4.5 billion years ago when the era of planet formation ended. These show that 2015 BZ509 has always moved in this way, and so could not have been there originally and must have been captured from another system.

[Continues . . . (https://www.sciencedaily.com/releases/2018/05/180521092717.htm)]
Title: Re: First Observation of an Interstellar Visitor
Post by: Tank on June 15, 2018, 06:23:55 AM
Wow, just wow.
Title: Re: First Observation of an Interstellar Visitor
Post by: Recusant on June 28, 2018, 12:36:11 PM
Current thinking based on observations is that 'Oumuamua is an interstellar comet or an alien space probe cunningly disguised as such.  ;)

"`Oumuamua gets a boost" | ScienceDaily (https://www.sciencedaily.com/releases/2018/06/180627160240.htm)

Quote`Oumuamua -- the first interstellar object discovered within our Solar System -- has been the subject of intense scrutiny since its discovery in October 2017. Now, by combining data from the ESO's Very Large Telescope and other observatories, an international team of astronomers has found that the object is moving faster than predicted. The measured gain in speed is tiny and `Oumuamua is still slowing down because of the pull of the Sun -- just not as fast as predicted by celestial mechanics.

The team, led by Marco Micheli (European Space Agency) explored several scenarios to explain the faster-than-predicted speed of this peculiar interstellar visitor. The most likely explanation is that `Oumuamua is venting material from its surface due to solar heating -- a behaviour known as outgassing. The thrust from this ejected material is thought to provide the small but steady push that is sending `Oumuamua hurtling out of the Solar System faster than expected -- as of 1 June 2018 it is traveling at roughly 114,000 kilometres per hour.

Such outgassing is a behaviour typical for comets and contradicts the previous classification of `Oumuamua as an interstellar asteroid. "We think this is a tiny, weird comet," commented Marco Micheli. "We can see in the data that its boost is getting smaller the farther away it travels from the Sun, which is typical for comets."

Usually, when comets are warmed by the Sun they eject dust and gas, which form a cloud of material -- called a coma (cometary) -- around them, as well as the characteristic tail . However, the research team could not detect any visual evidence of outgassing.

"We did not see any dust, coma, or tail, which is unusual," explained co-author Karen Meech of the University of Hawaii, USA. Meech led the discovery team's characterisation of `Oumuamua in 2017. "We think that 'Oumuamua may vent unusually large, coarse dust grains."

[Continues . . . (https://www.sciencedaily.com/releases/2018/06/180627160240.htm)]
Title: Re: First Observation of an Interstellar Visitor
Post by: Icarus on June 28, 2018, 08:58:49 PM
Hayabusa was a Suzuki Motorcycle but the new and different Hayabusa is even faster.  https://www.sciencenews.org/blog/science-ticker/japan-hayabusa2-spacecraft-arrives-asteroid-ryugu?utm_source=email&utm_medium=email&utm_campaign=latest-newsletter-v2
Title: Re: First Observation of an Interstellar Visitor
Post by: Recusant on January 15, 2019, 07:39:37 AM
Though the paper (https://arxiv.org/pdf/1810.11490.pdf) came out months ago, apparently it didn't get enough notice (to my shame I failed to catch it in the science news aggregators), so now one of the authors is doing interviews to get some publicity. "It really could have been a solar sail or even an alien probe. Really!" The main interview is in Haaretz, which has a strict paywall policy, so I've got a couple of other options.

"What is 'Oumuamua: Harvard Professor Avi Loeb defends his proposal it is an alien probe" | news.com.au (https://www.news.com.au/technology/science/space/what-is-oumuamua-harvard-professor-avi-loeb-defends-his-proposal-it-is-an-alien-probe/news-story/c6f197444eecd95863746a9b98653ead)

QuoteHarvard University Astronomy Department chair Avi Loeb is no stranger to controversy. His suggestion a strange object spotted entering our solar system from deep space could be an alien probe is just the most recent example.

Now, he's added fuel to the fire.

In an interview with the Israeli newspaper Haaretz, the Israeli professor has fiercely defended his hypothesis.

"As soon as we leave the solar system, I believe we will see a great deal of traffic out there," he said. "Possibly we'll get a message that says, 'Welcome to the interstellar club.' Or we'll discover multiple dead civilisations — that is, we'll find their remains."

At the heart of the debate is 'Oumuamua.

Translated from Hawaiian, it means "messenger sent from the distant past".

It came from outside the ecliptic — the flat swirl of planets, asteroids and stuff that was spun into place as our Solar System formed.

It was an odd reddish colour, suggesting extreme exposure to powerful cosmic rays.

It was relatively bright, at least compared with the average coal-black colour of most known comets and asteroids.

It was moving very, very fast. And it was seen to 'accelerate' as it moved away from the Sun as comets do. But it didn't have a comet's tail.

It was also seen to 'flicker' quickly, as though it was an elongated — or flat — object in a wild tumble.

'Oumuamua is certainly odd.

But, therefore aliens?

[Continues . . . (https://www.news.com.au/technology/science/space/what-is-oumuamua-harvard-professor-avi-loeb-defends-his-proposal-it-is-an-alien-probe/news-story/c6f197444eecd95863746a9b98653ead)]

"Thinking About Distant Civilizations Isn't Speculative" | Spiegel Online (http://www.spiegel.de/international/zeitgeist/astronomer-avi-loeb-on-the-interstellar-body-oumuamua-a-1246803.html)

QuoteDER SPIEGEL: Professor Loeb, do you have a favorite alien?

Loeb: To be honest, I don't like science fiction personally. I have a problem when the action in a movie violates the laws of physics. In those cases, I cannot enjoy the experience aesthetically.

DER SPIEGEL: If you don't like aliens, why are you exploring the question of intelligent extraterrestrial life?

Loeb: Because it's one of the really big questions. I have always been interested, even as a young kid, in thinking about the big picture. And the most fundamental of all questions is: Are we alone?

DER SPIEGEL: Why do you consider the question to be so fundamental?

Loeb: If at some point we encounter other intelligent beings, it would radically change our perspective of our importance in the big scheme of things. In addition, extraterrestrial intelligences could enormously increase our knowledge. Learning from them would improve our understanding of the world. It could be a shortcut -- just as if somebody from the Middle Ages were to get a glimpse of our world in the 21st century.

[Continues . . . (http://www.spiegel.de/international/zeitgeist/astronomer-avi-loeb-on-the-interstellar-body-oumuamua-a-1246803.html)]

Title: Re: First Observation of an Interstellar Visitor
Post by: Recusant on June 13, 2020, 10:03:32 PM
The latest hypothesis is that 'Oumuamua is a chunk of primordial hydrogen ice.

"Interstellar Oumuamua Was a Dark Hydrogen Iceberg" | Universe Today (https://www.universetoday.com/146360/interstellar-oumuamua-was-a-dark-hydrogen-iceberg/)

QuoteWhen Canadian astronomer Robert Weryk discovered `Oumuamua passing through our Solar System with the Pan-STARRS telescope, in October 2017, it caused quite a stir. It was the first interstellar object we'd ever seen coming through our neighbourhood. The excitement led to speculation: what could it be?

There was lots of fun conjecture on its origins. Was it an alien spacecraft? A solar sail? Or something more prosaic?

As more observational evidence rolled in, ideas on `Oumuamua's nature followed. Was it a comet? It had no coma, so some thought it was a partially disintegrated comet, or an extrasolar comet. Could it be an asteroid? `Oumuamua was similar to asteroids in some respects, like its rotation rate. But it was an elongated cigar-shaped object, not round.

[various hypotheses described]

Now, a new study presents evidence suggesting a different origin for our first interstellar visitor: It's not a fragment of a much larger body, but a chunk of frozen hydrogen. A space iceberg.

[. . .]

The sublimation of the molecular hydrogen ice explains `Oumuamua's acceleration. In their paper, Seligman and Laughton explain that "H2 sublimation at a rate proportional to the incident solar flux generates a surface-covering jet that reproduces the observed acceleration."

The authors say that the molecular hydrogen ice also explains `Oumuamua's strange cigar shape, unusual for an object in space. They write "Mass wasting from sublimation leads to monotonic increase in the body axis ratio, explaining 'Oumuamua's shape."

[Continues . . . (https://www.universetoday.com/146360/interstellar-oumuamua-was-a-dark-hydrogen-iceberg/)]

A draft version of the paper is available (PDF):

"Evidence that 1I/2017 U1 ('Oumuamua) was composed of molecular hydrogen ice." | Arxiv (https://arxiv.org/pdf/2005.12932.pdf)

QuoteAbstract:

'Oumuamua (I1 2017) was the first macroscopic (l ∼ 100 m) body observed to traverse the inner solar system on an unbound hyperbolic orbit. Its light curve displayed strong periodic variation, and it showed no hint of a coma or emission from molecular outgassing.

Astrometric measurements indicate that 'Oumuamua experienced non-gravitational acceleration on its outbound trajectory, but energy balance arguments indicate this acceleration is inconsistent with a water ice sublimation-driven jet of the type exhibited by solar system comets.

We show that all of 'Oumaumua's observed properties can be explained if it contained a significant fraction of molecular hydrogen (H2) ice. H2 sublimation at a rate proportional to the incident solar flux generates a surface-covering jet that reproduces the observed acceleration. Mass wasting from sublimation leads to monotonic increase in the body axis ratio, explaining 'Oumuamua's shape. Back-tracing 'Oumuamua's trajectory through the Solar System permits calculation of its mass and aspect ratio prior to encountering the Sun.

We show that H2-rich bodies plausibly form in the coldest dense cores of Giant Molecular Clouds, where number densities are of order n ∼ 105, and temperatures approach the T = 3 K background. Post-formation exposure to galactic cosmic rays implies a τ ∼ 100 Myr age, explaining the kinematics of 'Oumuamua's inbound trajectory.

[Paragraph breaks added. - R]



Title: Re: First Observation of an Interstellar Visitor
Post by: Ecurb Noselrub on June 14, 2020, 02:08:14 AM
For other ignoramuses like me, "sublimation" is when a solid goes to the gaseous phase without passing through the liquid phase, like ice cubes shrinking in the freezer. 

I propose making a cigar named Oumuamua and smoking it in honor of Oumuamua. 
Title: Re: First Observation of an Interstellar Visitor
Post by: hermes2015 on June 14, 2020, 04:21:34 AM
Quote from: Ecurb Noselrub on June 14, 2020, 02:08:14 AM
For other ignoramuses like me, "sublimation" is when a solid goes to the gaseous phase without passing through the liquid phase, like ice cubes shrinking in the freezer. 

I propose making a cigar named Oumuamua and smoking it in honor of Oumuamua.

Another example which is often given, but incorrectly, is iodine crystals. When heated, Iodine does in fact melt at 114°. One can boil the liquid iodine in a test tube to dry it, as I did many times when I needed anhydrous iodine. The boiling point is around 185°, when it refluxes on the inside walls of the test tube.
Title: Re: First Observation of an Interstellar Visitor
Post by: Tank on June 14, 2020, 10:04:31 AM
Quote from: hermes2015 on June 14, 2020, 04:21:34 AM
Quote from: Ecurb Noselrub on June 14, 2020, 02:08:14 AM
For other ignoramuses like me, "sublimation" is when a solid goes to the gaseous phase without passing through the liquid phase, like ice cubes shrinking in the freezer. 

I propose making a cigar named Oumuamua and smoking it in honor of Oumuamua.

Another example which is often given, but incorrectly, is iodine crystals. When heated, Iodine does in fact melt at 114°. One can boil the liquid iodine in a test tube to dry it, as I did many times when I needed anhydrous iodine. The boiling point is around 185°, when it refluxes on the inside walls of the test tube.

I love a 'geek mode' moment  :hug2:
Title: Re: First Observation of an Interstellar Visitor
Post by: hermes2015 on June 14, 2020, 10:09:31 AM
Quote from: Tank on June 14, 2020, 10:04:31 AM
Quote from: hermes2015 on June 14, 2020, 04:21:34 AM
Quote from: Ecurb Noselrub on June 14, 2020, 02:08:14 AM
For other ignoramuses like me, "sublimation" is when a solid goes to the gaseous phase without passing through the liquid phase, like ice cubes shrinking in the freezer. 

I propose making a cigar named Oumuamua and smoking it in honor of Oumuamua.

Another example which is often given, but incorrectly, is iodine crystals. When heated, Iodine does in fact melt at 114°. One can boil the liquid iodine in a test tube to dry it, as I did many times when I needed anhydrous iodine. The boiling point is around 185°, when it refluxes on the inside walls of the test tube.

I love a 'geek mode' moment  :hug2:

Thank you (I think). Not sure whether that is good or bad.
:unsure:
Title: Re: First Observation of an Interstellar Visitor
Post by: xSilverPhinx on June 14, 2020, 02:35:34 PM
Quote from: hermes2015 on June 14, 2020, 10:09:31 AM
Quote from: Tank on June 14, 2020, 10:04:31 AM
Quote from: hermes2015 on June 14, 2020, 04:21:34 AM
Quote from: Ecurb Noselrub on June 14, 2020, 02:08:14 AM
For other ignoramuses like me, "sublimation" is when a solid goes to the gaseous phase without passing through the liquid phase, like ice cubes shrinking in the freezer. 

I propose making a cigar named Oumuamua and smoking it in honor of Oumuamua.

Another example which is often given, but incorrectly, is iodine crystals. When heated, Iodine does in fact melt at 114°. One can boil the liquid iodine in a test tube to dry it, as I did many times when I needed anhydrous iodine. The boiling point is around 185°, when it refluxes on the inside walls of the test tube.

I love a 'geek mode' moment  :hug2:

Thank you (I think). Not sure whether that is good or bad.
:unsure:

:popcorn: It's good, no matter what others might say. :grin:
Title: Re: First Observation of an Interstellar Visitor
Post by: xSilverPhinx on June 14, 2020, 02:39:35 PM
Quote from: Ecurb Noselrub on June 14, 2020, 02:08:14 AM
I propose making a cigar named Oumuamua and smoking it in honor of Oumuamua.

:cheers: To Oomua...Ohmua...to *inaudible muffled sound*.  :smokin cool:
Title: Re: First Observation of an Interstellar Visitor
Post by: Randy on June 14, 2020, 03:44:04 PM
 :lol:
Title: Re: First Observation of an Interstellar Visitor
Post by: Recusant on March 20, 2021, 08:37:03 PM
A new hypothesis for the origin of 'Oumuamua.  Instead of hydrogen, the papers described below suggest that it was mostly composed of nitrogen. :thumb:

"Interstellar Object 'Oumuamua Is Likely a Piece of a Pluto-Like Planet" | American Geophysical Union (https://news.agu.org/press-release/interstellar-object-oumuamua-is-likely-a-piece-of-a-pluto-like-planet)

Quote
(https://i.imgur.com/FcMf4Oy.jpg)
Illustration of a plausible history for 'Oumuamua shows an origin in its parent system around 0.4 billion years ago; erosion by cosmic rays during its journey to the solar system; and passage through the solar system, including its closest approach to the Sun on 9 September 2017 and its discovery in October 2017. At each point along its history, this illustration shows the predicted size of 'Oumuamua, and the ratio between its longest and shortest dimensions.
Graphic credit: S. Selkirk/ASU,




The first known interstellar object to pass through our solar system is likely a piece of a Pluto-like planet from another solar system, according to a new study published as a pair of papers today in the Journal of Geophysical Research: Planets, AGU's journal for research on the formation and evolution of the planets, moons and objects of our solar system and beyond.

The results may help scientists learn about the stuff exoplanets are made of and the evolution of solar systems beyond our own.

"This research is exciting in that we've probably resolved the mystery of what 'Oumuamua is and we can reasonably identify it as a chunk of an 'exo-Pluto,' a Pluto-like planet in another solar system," said Steven Desch, an astrophysicist at Arizona State University and an author of the new study. "Until now, we've had no way to know if other solar systems have Pluto-like planets, but now we have seen a chunk of one pass by Earth."

Discovered in 2017 via the Pan-STARRS astronomical observatory in Hawaii, 1I/2017 U1 'Oumuamua, meaning 'scout' or 'messenger' in Hawaiian, hurtled past at 87.3 kilometers per second (196,000 miles per hour). The weirdly flat object was like a comet, but with features that were just odd enough to defy classification.

'Oumuamua's characteristics suggest it is likely made of solid nitrogen, like the surface of Pluto, according to the authors.

"It was likely knocked off the surface by an impact about half a billion years ago and thrown out of its parent system," said Alan Jackson, an astronomer and planetary scientist at Arizona State University and coauthor of the new study. Jackson will present the research on Wednesday, 17 March at the 52nd Lunar and Planetary Sciences Conference.

'Oumuamua likely wasn't flat when it entered our solar system, but melted away to a sliver, losing more than 95% of its mass, during its close encounter with the Sun, according to Jackson.

[Continues . . . (https://news.agu.org/press-release/interstellar-object-oumuamua-is-likely-a-piece-of-a-pluto-like-planet)]

There are links to the papers available at the AGU press release page above.
Title: Re: First Observation of an Interstellar Visitor
Post by: Randy on March 20, 2021, 11:36:10 PM
I didn't realize that people were still studying that thing. it's got to be pretty far out there by now. it must be from pictures taken on it's approach.
Title: Re: First Observation of an Interstellar Visitor
Post by: Davin on March 30, 2021, 07:12:54 PM
I didn't read this specific article, only the provided snippet, I'll read the rest later.

It had been detected that it picked up speed which is common for comets that get close to a star from an out-gassing process. But this one didn't look like the same kind of ice that would produce that kind of thing. Which is why they think it's likely nitrogen because when they plug nitrogen into the equations it matches all observed behavior. So unfortunately it's not and alien ship... at least not proven.

Now we'll have to see if that guy who wrote a book about how it's definitely aliens will handle this, correct himself or start speaking on the alien convention circuit.
Title: Re: First Observation of an Interstellar Visitor
Post by: Recusant on March 23, 2023, 02:33:22 AM
A refinement of the outgassing explanation for the observed acceleration. Those damned scientists are determined to stomp on our fantasies of interstellar voyagers.  :grrr:

"Sorry, E.T. fans: Interstellar visitor 'Oumuamua isn't an alien spacecraft. It's just passing gas." | Space.com (https://www.space.com/interstellar-object-oumuamua-acceleration-hydrogen-outgassing)

QuoteSince its surprise arrival in the solar system in 2017, the interstellar object 'Oumuamua has puzzled scientists. A duo of American astronomers now think they have solved one of the space rock's lingering mysteries.

First thought to be an asteroid, later recast as a likely comet, and by some even considered a possible alien spaceship, the 650-foot-long (200 meters) 'Oumuamua zoomed through the central solar system in late 2017. During its brief visit, the rock approached Earth within 15 million miles (24 million kilometers), about 62 Earth-moon distances, and disappeared a few weeks after its discovery.

Observations made within this short period of time soon proved that 'Oumuamua was on what astronomers call a "hyperbolic" orbit, a boomerang-shaped trajectory that indicated the rock is not native to our solar system but was only passing through the sun's neighborhood and would never be seen again.

[. . .]

Many scientists have tried to explain the mechanism behind 'Oumuamua's acceleration, but all of the proposed ideas have had significant gaps. In a new study, Jennifer Bergner, an assistant professor of chemistry at the University of California, Berkeley and Darryl Seligman, a U.S. National Science Foundation postdoctoral fellow at Cornell University, propose a new theory, which they think might finally put the issue to rest.

"I have been trying to explain the outgassing for several years now," Seligman told Space.com. "First, I thought that perhaps there just wasn't too much dust in the outgassing [to form the coma]. Later, we thought that perhaps it was made of some more volatile material than what we see in usual comets, such as hydrogen, nitrogen or carbon monoxide. But there were theoretical issues with each of these explanations."

Hydrogen, for example, would require extremely cold temperatures to freeze into objects the size of 'Oumuamua, and scientists don't expect such temperatures inside the dense molecular clouds where these objects form, Seligman said. Nitrogen is not ubiquitous enough in the Milky Way to account for the expected number of such bodies in the galaxy, he added.

Seligman and Bergner now propose that there might be nothing extraordinary about 'Oumuamua's chemistry. Instead, the object was subject to processes outside the solar system that astronomers don't know about from our observations of domestic comets.

"A comet traveling through the interstellar medium basically is getting cooked by cosmic radiation, forming hydrogen as a result," Bergner said in a statement(opens in new tab). "Our thought was: If this was happening, could you actually trap it in the body, so that when it entered the solar system and it was warmed up, it would outgas that hydrogen?"

Continues . . . (https://www.space.com/interstellar-object-oumuamua-acceleration-hydrogen-outgassing)

The paper (https://www.nature.com/articles/s41586-022-05687-w) is behind a paywall.

QuoteAbstract:

In 2017, 1I/'Oumuamua was identified as the first known interstellar object in the Solar System. Although typical cometary activity tracers were not detected, 'Oumuamua showed a notable non-gravitational acceleration. So far, there has been no explanation that can reconcile these constraints.

Owing to energetic considerations, outgassing of hyper-volatile molecules is favoured over heavier volatiles such as H2O and CO2. However, there are theoretical and/or observational inconsistencies with existing models invoking the sublimation of pure H2, N2 and CO. Non-outgassing explanations require fine-tuned formation mechanisms and/or unrealistic progenitor production rates.

Here we report that the acceleration of 'Oumuamua is due to the release of entrapped molecular hydrogen that formed through energetic processing of an H2O-rich icy body. In this model, 'Oumuamua began as an icy planetesimal that was irradiated at low temperatures by cosmic rays during its interstellar journey, and experienced warming during its passage through the Solar System.

This explanation is supported by a large body of experimental work showing that H2 is efficiently and generically produced from H2O ice processing, and that the entrapped H2 is released over a broad range of temperatures during annealing of the amorphous water matrix. We show that this mechanism can explain many of 'Oumuamua's peculiar properties without fine-tuning. This provides further support that 'Oumuamua originated as a planetesimal relic broadly similar to Solar System comets.
Title: Re: First Observation of an Interstellar Visitor
Post by: Tank on March 23, 2023, 08:58:17 AM
Bloody kill joys  >:(
Title: Re: First Observation of an Interstellar Visitor
Post by: Asmodean on March 23, 2023, 09:30:05 AM
The Asmo's own people, those. :smilenod:

Second Law of Asmodynamics clearly states that if a parade can be rained on, then you should bring a umbrella.