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Fraser
2016-Feb-04, 07:20 PM
Did scientists find a giant alien structure around KIC 8462852? Probably not, but if they did, what would these structures look like? In the summer of 2015, astronomers announced a strange new discovery from NASA’s planet hunting Kepler space observatory. Some object was blocking out about 22% of the light from its parent star: KIC […]
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Ross 54
2016-Feb-06, 04:23 PM
The scientific paper that brought wide attention to the star KIC 8462852 (Boyajian, et al., Where's the Flux?) made a good case for eliminating all reasonable astrophysical explanations, but one -- disrupted comets. With Dr. Bradley Schaefer's work, we now see that even this explanation is unworkable. We're frequently told that the megastructures explanation is very, very improbable. At this point, I wonder-- which astrophysical explanation is there still, that is so very much more probable than the work of an extraterrestrial civilization?

DaveC426913
2016-Feb-06, 05:21 PM
At this point, I wonder-- which astrophysical explanation is there still, that is so very much more probable than the work of an extraterrestrial civilization?
One we haven't seen yet. An unusual red dwarf, pulsing in a way we haven't seen before.

Unexpected sure, but many orders of magnitude more plausible than alien mega-structures.

cjameshuff
2016-Feb-06, 05:40 PM
One we haven't seen yet. An unusual red dwarf, pulsing in a way we haven't seen before.

Unexpected sure, but many orders of magnitude more plausible than alien mega-structures.

A red dwarf that looks like a flickering F-type star, larger, brighter, and hotter than our sun, is rather less plausible than a megastructure. Whatever Tabby's Star is, it's not a red dwarf.



The scientific paper that brought wide attention to the star KIC 8462852 (Boyajian, et al., Where's the Flux?) made a good case for eliminating all reasonable astrophysical explanations, but one -- disrupted comets. With Dr. Bradley Schaefer's work, we now see that even this explanation is unworkable. We're frequently told that the megastructures explanation is very, very improbable. At this point, I wonder-- which astrophysical explanation is there still, that is so very much more probable than the work of an extraterrestrial civilization?

Comets never made sense, the amount of cometary matter it would imply was clearly unrealistic. However, I'm not aware of anything that excludes an icy debris belt from a planetary collision. This would not be stable in the long term, the ices would eventually sublimate and be carried away leaving warmer rocky material behind, and it is improbable that we would happen to observe it just when it's in this state (a factor this explanation shares with a growing alien megastructure), but it seems to be a relatively plausible natural explanation.

Ross 54
2016-Feb-06, 09:12 PM
Since we don't know the number of stars with megastructures under construction at any given time, it's not clear to me how we can know the probability of observing one.
Wouldn't the destructive collision of a planet (with another planet?) leave behind a great deal of dust? This seems to be the chief objection that has been raised to this explanation. Infrared scattering due to excess dust was reportedly looked for repeatedly in this system, but was not found.

publiusr
2016-Feb-06, 09:16 PM
The Vogons didn't even put the traffic cones up.

danscope
2016-Feb-06, 10:57 PM
BUT........they did grace their company with Vogon poetry :)