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Tabby's star is dimming at an incredible rate

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Re: Tabby's star is dimming at an incredible rate

#41

Post by XorNot »

tazjin wrote: post #37
antognini wrote: post #19

Earlier quoted context omitted.

There wouldn't be any observed lensing because you have to be the right distance between the lens and the source for that to be observed. (For objects of comparable mass, the lens has to be roughly halfway in between the source and the observer) But if there were a black hole accreting matter from the host star, there would be an accretion disk which would be visible in X-ray. A black hole is also too small to explai…

Black holes are uniformly sized?

Schwarzchild radius means black holes are small. To dim the light from a star you need something very high in surface area whereas black holes by definition are the most compact objects in the universe

Re: Tabby's star is dimming at an incredible rate

#42

Post by fjarlq »

simcop2387 wrote: post #18

Two reddit discussion that might be able to answer some questions we have here: https://www.reddit.com/r/Astronomy/comments/4waozn/new_paper... https://www.reddit.com/r/KIC8462852/comments/4w7qfi/ben_mont... They also contain links to the resulting paper itself

Reddit user sigbjoernwilderness's idea is pretty wild... can it be easily ruled out?

> Is this the last remaining explanation after Montet/Simon?

> The dimming comes from the shadow of a spaceship traveling on an (almost) straight line from KIC8462852 to Earth. The slow continuous dimming results from the increase of the apparent size of the approaching ship while Earth/Kepler is in the penumbra. The irregular dips happen when Kepler accidentally passes the antumbra. A rough estimation by simple geometry would suggest that the alien spaceship is quite big (> 100 km diameter), significantly slower than light velocity (http://archimedes.soup.io/post/632873371/) The c200 days of "rapid decreased flux" between Kepler-day 1100 and 1300 (first half of 2012) which Monet/Simon reported, followed by a series of large dips after day 1500, would suggest a course correction with the space ship now on its final homing trajectory. -- Comments?

-- https://www.reddit.com/r/KIC8462852/comments/4w7qfi/ben_mont...

Re: Tabby's star is dimming at an incredible rate

#43

Post by m_mueller »

tazjin wrote: post #37
antognini wrote: post #19

Earlier quoted context omitted.

There wouldn't be any observed lensing because you have to be the right distance between the lens and the source for that to be observed. (For objects of comparable mass, the lens has to be roughly halfway in between the source and the observer) But if there were a black hole accreting matter from the host star, there would be an accretion disk which would be visible in X-ray. A black hole is also too small to explai…

Black holes are uniformly sized?

Stellar ones have a soft upper boundary. If they are so old and massive that they become planetary or even stellar sized - well the'd start drawing stealing a good chunk of the host galaxy and form their own one - with blackjack and hookers. I.e. a flickering star would be the least of your worries ;-).

Re: Tabby's star is dimming at an incredible rate

#44

Post by jimmytidey »

civilian wrote: post #40
zackya89 wrote: post #16

Earlier quoted context omitted.

that headline though ?, online journalism at its worst, the chase for clicks, there really needs to be some solution to this problem journalism is dying and clickbait is where is at.

"Extraordinary claims require extraordinary evidence", and this is the weirdest star we've seen. Your claims of clickbait are out of line, because we really don't know and alien megastructures is a reasonable theory. And 'alien megastructures' isn't even the most ridiculous idea: https://www.reddit.com/r/KIC8462852/comments/4w7qfi/ben_mont...

This is an amazing theory. What could possibly be more out there than alien life? Alien life in a gigantic spaceship accidentally coming between you and a star.

Re: Tabby's star is dimming at an incredible rate

#45

Post by ethanbond »

m_mueller wrote: post #43
tazjin wrote: post #37

Earlier quoted context omitted.

Black holes are uniformly sized?

Stellar ones have a soft upper boundary. If they are so old and massive that they become planetary or even stellar sized - well the'd start drawing stealing a good chunk of the host galaxy and form their own one - with blackjack and hookers. I.e. a flickering star would be the least of your worries ;-).

What causes the soft upper boundary?

Re: Tabby's star is dimming at an incredible rate

#46

Post by imaginenore »

fjarlq wrote: post #42
simcop2387 wrote: post #18

Two reddit discussion that might be able to answer some questions we have here: https://www.reddit.com/r/Astronomy/comments/4waozn/new_paper... https://www.reddit.com/r/KIC8462852/comments/4w7qfi/ben_mont... They also contain links to the resulting paper itself

Reddit user sigbjoernwilderness's idea is pretty wild... can it be easily ruled out? > Is this the last remaining explanation after Montet/Simon? > The dimming comes from the shadow of a spaceship traveling on an (almost) straight line from KIC8462852 to Earth. The slow continuous dimming results from the increase of the apparent size of the approaching ship while Earth/Kepler is in the penumbra. The irregular dips h…

How can a ship 100 km in diameter cause any significant dimming of a star, which is 21,980,000 km in diameter? It would have to be pretty close to here and lined up just so perfectly.

Why even assume it's a spaceship and not an asteroid or a rogue planet?

Re: Tabby's star is dimming at an incredible rate

#47

Post by david-given »

jerf wrote: post #38
david-given wrote: post #36

Earlier quoted context omitted.

Finding information on this appears to be kinda hard, but it looks like the best estimate for the 'kill radius' of a supernova (i.e. will cause mass extinctions) is 30 light years. So this is about two orders of magnitudes away, which means the effect will be two orders of magnitude lesser. Eta Corina is a double star containing at least one hypergiant that's going to go supernova any epoch now, so it gets studied a…

"So this is about two orders of magnitudes away, which means the effect will be two orders of magnitude lesser." Inverse square applies here; moving 100 times farther away makes the effect 10,000 times less. (I have to say it "applies here" because people sometimes overapply the law. It only applies when something is spreading out in an even sphere. However, that applies to supernovae, or at least close enough.) You'…

> Inverse square applies here; moving 100 times farther away makes the effect 10,000 times less.

Oh, bah. Yes, of course. My upbringing in Flatland is obviously showing.

Re: Tabby's star is dimming at an incredible rate

#48

Post by singularity2001 »

Sunspots, debris and/or a distant cloud are not completely ruled out: https://arxiv.org/abs/1608.01316

Wiki:

The leading hypothesis, based on a lack of observed infrared light, is that of a swarm of cold, dusty comet fragments in a highly eccentric orbit.[12][13][14] Many small masses in "tight formation" orbiting the star have also been proposed.[9] The changes in brightness could be signs of activity associated with intelligent extraterrestrial life building a Dyson swarm.[9][15][16][17] The SETI Institute's initial radio reconnaissance of KIC 8462852, however, found no evidence of technology-related radio signals from the star.

https://en.wikipedia.org/wiki/KIC_8462852

Re: Tabby's star is dimming at an incredible rate

#50

Post by civilian »

imaginenore wrote: post #46
fjarlq wrote: post #42

Earlier quoted context omitted.

Reddit user sigbjoernwilderness's idea is pretty wild... can it be easily ruled out? > Is this the last remaining explanation after Montet/Simon? > The dimming comes from the shadow of a spaceship traveling on an (almost) straight line from KIC8462852 to Earth. The slow continuous dimming results from the increase of the apparent size of the approaching ship while Earth/Kepler is in the penumbra. The irregular dips h…

How can a ship 100 km in diameter cause any significant dimming of a star, which is 21,980,000 km in diameter? It would have to be pretty close to here and lined up just so perfectly. Why even assume it's a spaceship and not an asteroid or a rogue planet?

Because we're brainstorming here! They're not assuming anything.

But yes, that's exactly the theory, that the starship is somewhere between us and them, and it sometimes dips into the focal point of light.

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