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-   -   Oumuamua signals: SETI's listening (http://www.oldrocketforum.com/showthread.php?t=17017)

blackshire 12-13-2017 02:06 AM

Oumuamua signals: SETI's listening
 
Hello All,

Enough doubt exists that the interstellar asteroid Oumuamua may *not* be a natural object that additional observations—including radio telescope observations by SETI and Breakthrough Listen, to detect any leakage radiation from it—are now being conducted (see: http://www.google.com/search?ei=Vdo...1.0.ShVFCFHnMbY ). Its natural-seeming photometric reddish color (combined with its very odd total lack of cometary outgassing despite this), its needle-like proportions (~800 meters long, yet only ~80 meters wide), its obvious strength and solidity (a “rubble pile” of those proportions would have broken apart even given Oumuamua’s relatively slow rotation), and its high-velocity entry into our solar system, have raised suspicions among some scientists that Oumuamua might possibly be an interstellar probe or a starship—perhaps a derelict one—instead of a natural object.

mojo1986 12-13-2017 06:45 AM

An interstellar probe or a starship? I'm betting it's not. Those SETI guys should have better things to do...........

astronwolf 12-13-2017 09:41 AM

It does excite the imagination, but lack of cometary out-gassing and a red color are IMHO not possible clues that this may be a spaceship. Deep space objects seem to get coated with a red-colored goo that is composed of a class of compounds called tholins. And there is no reason a priori that an object flying past us on a hyperbolic trajectory through the solar system should out-gas.

It's a fairly small object with a low albedo. Amazing that they even saw it last October.

blackshire 12-13-2017 06:08 PM

Quote:
Originally Posted by astronwolf
It does excite the imagination, but lack of cometary out-gassing and a red color are IMHO not possible clues that this may be a spaceship. Deep space objects seem to get coated with a red-colored goo that is composed of a class of compounds called tholins. And there is no reason a priori that an object flying past us on a hyperbolic trajectory through the solar system should out-gas.

It's a fairly small object with a low albedo. Amazing that they even saw it last October.
I agree that the starprobe/starship hypothesis is quite unlikely (all of the scientists who are conducting the radio and optical observations of Oumuamua also think that), but--as Carl Sagan would say--we should beware of Earth chauvinisms and human chauvinisms. The "default mental image" of an interstellar vehicle--in human minds--is that of a manufactured craft, but alien minds might, perhaps based on their own space-faring experience, conceive of an asteroid outfitted (or even re-configured) as a starprobe or a starship instead, and:

Even a few human beings--scientists and engineers, as well as science fiction writers--who have contemplated and studied the problems posed by interstellar space flight have suggested using (and even re-shaping) asteroids for use as starships, particularly slow (sub-relativistic velocity) ones. The "walls" of such asteroids would provide shielding against radiation (including galactic cosmic rays) and interstellar particle impacts, as well as help to maintain an even interior temperature for equipment and occupants (if any). Also:

While it is unlikely that Oumuamua is an interstellar vehicle of any kind (it probably *is* a tholins-coated asteroid--or a thickly-coated comet nucleus, perhaps--that was ejected from its stellar system of origin by a Jovian planet [and or companion star] gravitational encounter), it doesn't hurt to give it another, more detailed look. Whether it is natural or artificial (or a modified natural celestial body), any new--or even confirmatory, or dis-confirmatory--data that can be gleaned from Oumuamua is worthwhile to obtain.

tbzep 12-13-2017 06:47 PM

99.999% unlikely. However, it takes only a few keystrokes to receive and study possible radio emissions, so why not take a peek?

blackshire 12-13-2017 07:01 PM

Quote:
Originally Posted by tbzep
99.999% unlikely. However, it takes only a few keystrokes to receive and study possible radio emissions, so why not take a peek?
Indeed--also, some astronomers think that such "interstellar interlopers" may be more common, and may pass (undetected) through our solar system, than has been thought up to now. (Small, dark objects that never pass closer to the Sun than, say, Saturn, might never be seen; even closer solar encounters might go unnoticed if they occurred sunward of the Earth [when Comet Halley transited the Sun's disc during its 1910 apparition, its nucleus--which is several times larger than Oumuamua--wasn't seen at all].) In addition:

Proposed missions to Oumuamua have been formulated. Here (see: http://danielmarin.naukas.com/2017/...%CA%BBoumuamua/ ) is a proposal for an SLS-launched (SpaceX’s BFR could also do it) probe that could reach Oumuamua. The text is in Portuguese (the proposal is from Brazil), but FreeTranslation www.freetranslation.com can translate it into English. Such a probe could also--in principle (although spacecraft longevity would be an issue)--be sent to another star, in which case a laser communication system could be used instead of the "baseline" 1-meter dish antenna.

blackshire 12-13-2017 07:19 PM

Speaking of interstellar probes:

The founder of “Project Vagabond” http://twitter.com/VagabondArmada posted here (see: http://twitter.com/_TheGeoff/status/933480336025145345 ) about an interesting multi-star mission; as he described it (I have also copied it below):

Project Vagabond‏ @VagabondArmada Nov 21 More
Replying to @EricMamajek

A probe in an slightly elliptical Galactic orbit, but traveling in the counter-revolving direction would be best case - going by stars at an average of about 460 km/sec - it could rack up an enormous number of stellar flybys. Easy for a machine.

tbzep 12-13-2017 08:32 PM

Oumuamua...what a name! Next one to come through should be called Mahna Mahna!

https://www.youtube.com/watch?v=y5W60VwDkas

blackshire 12-13-2017 09:28 PM

Quote:
Originally Posted by tbzep
Oumuamua...what a name! Next one to come through should be called Mahna Mahna!

https://www.youtube.com/watch?v=y5W60VwDkas
Thank you for posting this video--I'd forgotten about them! There are other, hardly less unusual, naming traditions for various types of celestial bodies. :-) With classical Greco-Roman names being pretty "mined out" (Chiron-type "ice-teroids" are named after centaurs, asteroids were named after goddesses and nymphs [and later, gods, universities, pets, astronomers' girlfriends, etc.]), "Sesame Street" represents a fresh "vein" of names for interstellar asteroids and comets. (The fact that such objects will likely never be seen again or visited, unless there are great space propulsion advances, also makes giving them whimsical names less problematic [astronomers could stick with their official, alphanumeric designations], and the unofficial names given to lunar features for Apollo provide a precedent of sorts.) For example:

As well as Mahna Mahna (which would continue the repeating-syllables format of Oumuamua), future "I-class" asteroids and comets could be given names such as Count von Count and Maughty-moot-mope. Binary I-class objects could be given names that cover *both* components. Thus, we may one day discover interstellar interlopers that leave the Sol system with monikers such as Bert & Ernie, Buddy & Jim (two ^human^ comedians who appeared on "Sesame Street" during its early years), and Geeful & Gonk (these last two resided on an extra-solar planet called Snu [pronounced "snoo"], so they have an intrinsic interstellar association...).

tbzep 12-13-2017 09:48 PM

And we can't forget the guy singing Mahna Mahna, Bip Bippadotta.

A few others that have stuck with me for 50 years in addition to the more common Cookie Monster, Big Bird, Grover, Oscar, etc. are:
Marvelous Martha (MMMMMMMM, Martha! cartoon segment)
Wicked Wanda (cartoon segment)
Yip Yips (aliens......cow, book, telephone)

This post was brought to you by the letters Q and U and the number 6.


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