5 ms·

Astronomers may have found giant alien 'megastructures' orbiting star

18 points by awjr 11y ago

DomBlack 11y ago
Link to the paper http://arxiv.org/pdf/1509.03622v1.pdf http://arxiv.org/pdf/1509.03622v1.pdf
fjarlq 11y ago
Phil Plait's take on it: http://www.slate.com/blogs/bad_astronomy/2015/10/14/weird_star_strange_dips_in_brightness_are_a_bit_baffling.html http://www.slate.com/blogs/bad_astronomy/2015/10/14/weird_st...
hliyan 11y ago
As much as I'd like to believe it, another case like the faster-than-light-neutrino incident is more likely than alien megastructures.
koverstreet 11y ago
Just finished reading the paper. It's worth reading - it's well written and they've already put a lot of effort into characterizing the star, and modelling/ruling out any explanations they could think of. The thing that makes this star _really_ peculiar is the lack of any excess infrared - if there was as much material (dust, asteroids, debris) orbiting the star as you'd expect from how often/how much the star is being occulted (that is, there should be a lot more material on orbits that don't intersect with our line of sight) - then there should be quite a bit of excess infrared radiation from all that material, but we don't. The most plausible explanation they could come up with is comets - but the profile of the occultation events doesn't match comets very well (sharp dip initially corresponding to the optically thick head of the comet, then a slower rise back to normal from the tail). My question regarding the comet hypothesis is - could there even be enough material in the oort cloud to produce the amount of occultation we're seeing? Given that Jupiter apparently only occults our sun by 1% and we're seeing 22% occultation here, it seems unlikely. You'd have to assume an average object size to calculate % occultation -> mass of occulting objects, but we should be able to make a reasonable assumption on that from observations in our own solar system. And apparently our own oort cloud has been estimated at a few earth masses, so if that's typical we've got a rough upper bound for the amount of material available. I wonder if anyone's done that calculation yet.
dang 11y ago
https://news.ycombinator.com/item?id=10386214 https://news.ycombinator.com/item?id=10386214

18 points by awjr 11y ago

Link to the paper http://arxiv.org/pdf/1509.03622v1.pdf http://arxiv.org/pdf/1509.03622v1.pdf

Phil Plait's take on it: http://www.slate.com/blogs/bad_astronomy/2015/10/14/weird_star_strange_dips_in_brightness_are_a_bit_baffling.html http://www.slate.com/blogs/bad_astronomy/2015/10/14/weird_st...

hliyan 11y ago

As much as I'd like to believe it, another case like the faster-than-light-neutrino incident is more likely than alien megastructures.

koverstreet 11y ago

Just finished reading the paper. It's worth reading - it's well written and they've already put a lot of effort into characterizing the star, and modelling/ruling out any explanations they could think of. The thing that makes this star _really_ peculiar is the lack of any excess infrared - if there was as much material (dust, asteroids, debris) orbiting the star as you'd expect from how often/how much the star is being occulted (that is, there should be a lot more material on orbits that don't intersect with our line of sight) - then there should be quite a bit of excess infrared radiation from all that material, but we don't. The most plausible explanation they could come up with is comets - but the profile of the occultation events doesn't match comets very well (sharp dip initially corresponding to the optically thick head of the comet, then a slower rise back to normal from the tail). My question regarding the comet hypothesis is - could there even be enough material in the oort cloud to produce the amount of occultation we're seeing? Given that Jupiter apparently only occults our sun by 1% and we're seeing 22% occultation here, it seems unlikely. You'd have to assume an average object size to calculate % occultation -> mass of occulting objects, but we should be able to make a reasonable assumption on that from observations in our own solar system. And apparently our own oort cloud has been estimated at a few earth masses, so if that's typical we've got a rough upper bound for the amount of material available. I wonder if anyone's done that calculation yet.

dang 11y ago

https://news.ycombinator.com/item?id=10386214 https://news.ycombinator.com/item?id=10386214