Author Topic: Hyperbolic Hyperbole or Interstellar Interloper? ('Oumuamua)  (Read 40703 times)

Offline Star One

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Re: Hyperbolic Hyperbole or Interstellar Interloper? ('Oumuamua)
« Reply #280 on: 12/11/2017 07:25 PM »
Breakthrough Listen is to scan Oumuamua just to make sure it isn’t an alien spaceship.

Here’s the press release.

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San Francisco – December 11, 2017 – Breakthrough Listen, the global astronomical program searching for evidence of civilizations beyond Earth, announced that it is currently focusing its observational efforts on ‘Oumuamua, the mysterious interloper recently spotted moving rapidly through the solar system.
‘Oumuamua was discovered by the Pan-STARRS project at the University of Hawaii in October 2017, passing Earth at about 85 times the distance to the Moon – a stone’s throw, in astronomical terms. It is the first object discovered in the solar system that appears to originate from another star system. Its high speed – 196,000 mph at its peak – suggests it is not gravitationally bound to the Sun, but will continue its voyage back into interstellar space. It has a highly unusual structure for an asteroid – an elongated cigar shape, hundreds of meters in length but with width and height perhaps only one tenth as long.
Researchers working on long-distance space transportation have previously suggested that a cigar or needle shape is the most likely architecture for an interstellar spacecraft, since this would minimize friction and damage from interstellar gas and dust. While a natural origin is more likely, there is currently no consensus on what that origin might have been, and Breakthrough Listen is well positioned to explore the possibility that ‘Oumuamua could be an artifact.
Listen’s observation campaign will begin on Wednesday, December 13 at 3:00 pm ET. Using the Robert C. Byrd Green Bank Telescope, it will continue to observe ‘Oumuamua across four radio bands, from 1 to 12 GHz. Its first phase of observations will last a total of 10 hours, divided into four “epochs” based on the object’s period of rotation.
‘Oumuamua is now about 2 astronomical units (AU) away, or twice the distance between Earth and the Sun. This is closer by a factor of 50-70 than the most distant human artifact, the Voyager I spacecraft. At this distance, it would take under a minute for the Green Bank instrument to detect an omnidirectional transmitter with the power of a cellphone.
“‘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,” said Listen’s Andrew Siemion, Director of Berkeley SETI Research Center. “Whether this object turns out to be artificial or natural, it’s a great target for Listen.”
Even if no signal or other evidence of extraterrestrial technology is heard, Listen observations will cover portions of the radio spectrum in which the object has not yet been observed, and could provide important information about the possibility of water/ice, or the chemistry of a coma (gaseous envelope), neither of which have yet been identified. Listen has already proved its value for traditional, non-SETI astronomy: in August 2017 it detected several dozen repeating fast radio bursts (FRBs) from a distant dwarf galaxy – for details see www.astronomerstelegram.org/?read=10675.

http://breakthroughinitiatives.org/news/14

Offline sanman

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Offline Mongo62

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Re: Hyperbolic Hyperbole or Interstellar Interloper? ('Oumuamua)
« Reply #283 on: 12/13/2017 01:28 AM »
Explaining the elongated shape of 'Oumuamua by the Eikonal abrasion model

The photometry of the minor body with extrasolar origin (1I/2017 U1) 'Oumuamua revealed an unprecedented shape: Meech et al. (2017) reported a shape elongation b/a close to 1/10, which calls for theoretical explanation. Here we show that the abrasion of a primordial asteroid by a huge number of tiny particles ultimately leads to such elongated shape. The model (called the Eikonal equation) predicting this outcome was already suggested in Domokos et al. (2009) to play an important role in the evolution of asteroid shapes.

Ejection of rocky and icy material from binary star systems: Implications for the origin and composition of 1I/`Oumuamua

In single star systems like our own Solar system, comets dominate the mass budget of bodies that are ejected into interstellar space, since they form further away and are less tightly bound. However 1I/`Oumuamua, the first interstellar object detected, appears asteroidal in its spectra and in its lack of detectable activity. We argue that the galactic budget of interstellar objects like 1I/`Oumuamua should be dominated by planetesimal material ejected during planet formation in circumbinary systems, rather than in single star systems or widely separated binaries. We further show that in circumbinary systems, rocky bodies should be ejected in comparable numbers to icy ones. This suggests that a substantial fraction of additional interstellar objects discovered in the future should display an active coma. We find that the rocky population, of which 1I/`Oumuamua seems to be a member, should be predominantly sourced from A-type and late B-star binaries.

Offline JasonAW3

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Re: Hyperbolic Hyperbole or Interstellar Interloper? ('Oumuamua)
« Reply #284 on: 12/13/2017 03:04 AM »
Scanning for signs of technology:

https://www.theatlantic.com/science/archive/2017/12/yuri-milner-oumuamua-interstellar-asteroid/547985/

Probably wouldn't be a bad idea to point an x-ray telescope at this asteroid.  An IR check could also be useful, primarily to get an idea of stresses from its' tumbling.  Any chance of getting radar images of it, or is it too far out now?
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Offline Star One

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Hyperbolic Hyperbole or Interstellar Interloper? ('Oumuamua)
« Reply #285 on: 12/13/2017 05:02 PM »
Decent summation of where we stand now with our knowledge of Oumuamua.

« Last Edit: 12/13/2017 05:02 PM by Star One »

Offline whitelancer64

Scanning for signs of technology:

https://www.theatlantic.com/science/archive/2017/12/yuri-milner-oumuamua-interstellar-asteroid/547985/

Probably wouldn't be a bad idea to point an x-ray telescope at this asteroid.  An IR check could also be useful, primarily to get an idea of stresses from its' tumbling.  Any chance of getting radar images of it, or is it too far out now?

It has already been observed in IR, by Spitzer. Hubble was also used for observations. It is currently farther from the Sun than Mars is, much too far for good radar data on it. Had we discovered it before its closest approach to Earth (which was still 24 million kilometers, 15 million miles away), we could have gotten some OK radar images of it.
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Offline Zed_Noir

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Re: Hyperbolic Hyperbole or Interstellar Interloper? ('Oumuamua)
« Reply #287 on: 12/14/2017 01:36 AM »
Decent summation of where we stand now with our knowledge of Oumuamua.



Doesn't rule anything out except that it is unlikely to be pile of stuff from accumulated space debris.




Offline RotoSequence

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Re: Hyperbolic Hyperbole or Interstellar Interloper? ('Oumuamua)
« Reply #288 on: 12/14/2017 01:51 AM »
Space Time did an episode on Oumuamua  :)


Offline Dao Angkan

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Re: Hyperbolic Hyperbole or Interstellar Interloper? ('Oumuamua)
« Reply #289 on: 12/14/2017 07:15 PM »
Sky News in the UK had a live interview yesterday with one of the SETI guys at one of their observatories in the US. The presenter did a good job of asking sensible questions for what could be a sensationalist story, and the SETI guy did a good job of explaining what they're doing to the lay-person. There was even a discussion on the difference between METI and SETI (the presenter brought up that Stephen Hawking says that we should hide from ET), the SETI guy acknowledged that there is a big debate about this, but he falls on the "hide" side, and that SETI only listens.

It was a fun news piece (which is always welcome), whilst also showing science and astronomy in a good light. I don't know if SETI will ever find anything, but I think they do a good job of inspiring people and making space fun.

Offline ncb1397

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Re: Hyperbolic Hyperbole or Interstellar Interloper? ('Oumuamua)
« Reply #290 on: 12/14/2017 08:09 PM »
Quote
Interstellar Visitor Stays Silent: No Signs of Life Yet on 'Oumuamua
https://www.space.com/39100-interstellar-object-oumuamua-alien-life-search.html?utm_source=notification

Probably not the best strategy to broadcast on the net when you will be listening if you want to pick something up from something that may not want you picking anything up. But any signals would likely be directional and thus this will probably only pick up anything if it was trying to make contact.
« Last Edit: 12/15/2017 03:30 AM by ncb1397 »

Offline Dao Angkan

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Re: Hyperbolic Hyperbole or Interstellar Interloper? ('Oumuamua)
« Reply #291 on: 12/14/2017 08:54 PM »
Quote
Interstellar Visitor Stays Silent: No Signs of Life Yet on 'Oumuamua
https://www.space.com/39100-interstellar-object-oumuamua-alien-life-search.html?utm_source=notification

Probably not the best strategy to broadcast on the net when you will be listening if you want to pick something up from something that may not want you pick anything up. But any signals would likely be directional and thus this will probably only pick up anything if it was trying to make contact.

So we can say that they're not METI at least! :)
« Last Edit: 12/14/2017 08:54 PM by Dao Angkan »

Offline JasonAW3

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Re: Hyperbolic Hyperbole or Interstellar Interloper? ('Oumuamua)
« Reply #292 on: 12/14/2017 11:31 PM »
Scanning for signs of technology:

https://www.theatlantic.com/science/archive/2017/12/yuri-milner-oumuamua-interstellar-asteroid/547985/

Probably wouldn't be a bad idea to point an x-ray telescope at this asteroid.  An IR check could also be useful, primarily to get an idea of stresses from its' tumbling.  Any chance of getting radar images of it, or is it too far out now?

It has already been observed in IR, by Spitzer. Hubble was also used for observations. It is currently farther from the Sun than Mars is, much too far for good radar data on it. Had we discovered it before its closest approach to Earth (which was still 24 million kilometers, 15 million miles away), we could have gotten some OK radar images of it.

This may seem slightly off topic, but it might not be a bad idea to orbit a few radio telescopes, maybe in the Earth - Moon Lagrange points, or possibly the solar Lagrange points.  A strong RF point source that could be used for long range radio mapping wouldn't be a bad idea as well.  Not only would they be useful for stellar observation, but useful for deep space observation of asteroids, comets, planets and other unusual objects.

      We could probably use inflatable structures for the telescopes, as this would provide the most structure for the least mass.
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Online hop

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Re: Hyperbolic Hyperbole or Interstellar Interloper? ('Oumuamua)
« Reply #293 on: 12/16/2017 10:35 PM »
Karen Meech and collaborators secured additional HST time http://www.stsci.edu/cgi-bin/get-proposal-info?id=15447&observatory=HST

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We request four additional HST/WFC3/UVIS orbits of 1I/217 U1 ('Oumuamua), our Solar System's first interstellar visitor, in order to complete our DD program 15405. Our science goal is to obtain precise astrometry along an extended arc length in order  to identify the region from which this object originated. Since the rotational light curve of 'Oumuamua shows variations of as much as 2.5 mag in brightness, a secure detection in the HST single exposures needed to maximize astrometric precision can only be assured in observations conducted at light curve maximum. However, we and other teams have recently determined that `Oumuamua is in a state of excited rotation and that, contrary to our intial expectations, we cannot predict the rotational phase in early January from existing data. We thus request four additional HST orbits that will allow us to sample `Oumuamua's light curve at multiple rotation phases, thereby ensuring that program 15405 will obtain a secure, final detection of our target that is crucial for this program to achieve its scientific objective.

Offline Star One

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Re: Hyperbolic Hyperbole or Interstellar Interloper? ('Oumuamua)
« Reply #294 on: 12/18/2017 03:52 PM »
Interstellar object ‘Oumuamua covered in 'thick crust of carbon-rich gunk

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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.

https://www.theguardian.com/science/2017/dec/18/interstellar-object-oumuamua-covered-in-thick-crust-of-carbon-rich-gunk

Offline jebbo

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Re: Hyperbolic Hyperbole or Interstellar Interloper? ('Oumuamua)
« Reply #295 on: 12/18/2017 04:26 PM »
The paper cited above:

Spectroscopy and thermal modelling of the first interstellar object 1I/2017 U1 ‘Oumuamua
Quote
During the formation and evolution of the Solar System, significant numbers of cometary and asteroidal bodies were ejected into interstellar space1,2. It is reasonable to expect that the same happened for planetary systems other than our own. Detection of such interstellar objects would allow us to probe the planetesimal formation processes around other stars, possibly together with the effects of long-term exposure to the interstellar medium. 1I/2017 U1 ‘Oumuamua is the first known interstellar object, discovered by the Pan-STARRS1 telescope in October 2017 (ref. 3). The discovery epoch photometry implies a highly elongated body with radii of ~ 200 × 20 m when a comet-like geometric albedo of 0.04 is assumed. The observable interstellar object population is expected to be dominated by comet-like bodies in agreement with our spectra, yet the reported inactivity of 'Oumuamua implies a lack of surface ice. Here, we report spectroscopic characterization of ‘Oumuamua, finding it to be variable with time but similar to organically rich surfaces found in the outer Solar System. We show that this is consistent with predictions of an insulating mantle produced by long-term cosmic ray exposure4. An internal icy composition cannot therefore be ruled out by the lack of activity, even though ‘Oumuamua passed within 0.25 au of the Sun.
https://www.nature.com/articles/s41550-017-0361-4?utm_content=bufferc0423&utm_medium=social&utm_source=twitter.com&utm_campaign=buffer

Offline Star One

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Hyperbolic Hyperbole or Interstellar Interloper? ('Oumuamua)
« Reply #296 on: 12/18/2017 04:52 PM »
An ideal habitat for basic life especially as that coating would probably protect it from the worst of interstellar radiation.

Quote
Fitzsimmons' team estimates that outer layer might have reached temperatures as high as 300 degrees Celsius during 'Oumuamua's closest pass of the sun, but that it would have provided enough insulation to prevent ice inside from vaporizing. Which raises the question: Could it have protected life inside the asteroid, perhaps waterborne microbes, from vaporizing as well?

I mean, technically? Yes. But Meech says that a far greater risk to microbial life would be the same cosmic rays that cooked 'Oumuamua's outside in the first place. Only if something were buried deep inside of the asteroid (say, at a distance of a few meters) would it be shielded from the harsh radiation of space.

https://www.wired.com/story/oumuamua-probably-isnt-a-spaceshipbut-it-could-have-passengers/
« Last Edit: 12/18/2017 05:18 PM by Star One »

Offline Mongo62

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Re: Hyperbolic Hyperbole or Interstellar Interloper? ('Oumuamua)
« Reply #297 on: 12/19/2017 01:01 AM »
On Distinguishing Interstellar Objects Like `Oumuamua From Products of Solar System Scattering

Schneider (2018) explored the possibility that 'Oumuamua is a Solar System object, and concluded that if it is, it must have been scattered by "another, yet unknown planet." I provide an extremely conservative upper limit on post-scattering velocities in the Solar System to show that 'Oumuamua is moving far to quickly to be the result of any hypothetical single scattering event between any bound Solar System objects within 21 au (a distance within which our understanding of objects capable of scattering 'Oumuamua is presumably complete).

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Offline Mongo62

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Re: Hyperbolic Hyperbole or Interstellar Interloper? ('Oumuamua)
« Reply #299 on: 12/20/2017 12:55 AM »
What and Whence 1I/`Oumuamua?

The first confirmed interstellar interloper in our Solar System, 1I/`Oumuamua, is likely to be a minor body ejected from another star, but its brief flyby and faintness made it difficult to study. Two remarkable properties are its large (2-2.5 mag) rotational variability and its motion relative to the Sun before encounter. The former suggests an extremely elongated (>10:1) shape and the latter an origin from the protoplanetary disk of a young star in a nearby association. 1I/`Oumuamua's variability can also be explained if it is a contact binary of near-equilibrium ellipsoidal components and heterogeneous surfaces, i.e. brighter, dust-mantled inner-facing hemispheres and darker, dust-free outer-facing poles. The probability that 1I/`Oumuamua has the same motion as a young stellar association is <1%. One explanation for the youth of 1I/`Oumuamua relative to the Solar neighborhood mean it that loss of dust mantles and darkening of lag surfaces by cosmic rays renders similar objects undetectable in a few 100's of Myr. In this scenario, 1I/`Oumuamua is smaller and much less massive, but represents a more numerous population of ejected planetesimals. Studies of such objects are a potential means to probe early planet formation, complementing observations of protoplanetary disks and studies of meteorites.

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