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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

#31

Post by lucb1e »

jerf wrote: post #22
lucb1e wrote: post #20

Earlier quoted context omitted.

Well whatever it is, we probably have 1000+ years to save ourselves right? If whatever caused it comes at us at 50% light speed, which sounds unlikely given how fast that already is, we'd still have 700 years. I'm pretty sure that if human's resources were suddenly all turned towards getting the hell out of here, we could certainly pull it off for a good part of the population in a few hundred years. Whether we'd eve…

"Well whatever it is, we probably have 1000+ years to save ourselves right?" No. That time has already passed. If we see signs that the star will go nova "in one year", we have one year, not 1481. The popular idea that we see "the past" in the sky is not really the best way to think about it. It is far more accurate to say that there is no such thing as "the" present, and what we see in the sky really is our present.…

So what's the risk if it turns supernova in one year? As you say, it's 1500 ly away, not You sound way more expert on this than me (I had no idea lightyears had a notation, ly, nor that supernovas are dangerous to us as far as 50ly away), so I'll assume what you say is accurate, but I still see no imminent threat.

I'm also not suggesting we'd have the full 1481 years, since we don't see what's presently there but what was there, but as long as the phenomenon doesn't travel at the speed of light (and it doesn't, or we would be experiencing it already, since we can observe the effect) we still have time.

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

#32

Post by lucb1e »

ridgeguy wrote: post #25
lucb1e wrote: post #20

Earlier quoted context omitted.

Well whatever it is, we probably have 1000+ years to save ourselves right? If whatever caused it comes at us at 50% light speed, which sounds unlikely given how fast that already is, we'd still have 700 years. I'm pretty sure that if human's resources were suddenly all turned towards getting the hell out of here, we could certainly pull it off for a good part of the population in a few hundred years. Whether we'd eve…

Depends on how long ago "they" developed telescopes capable of viewing Earth with good resolution. We know in principle how to build such instruments. "They" may have watched the Romans build roads and sussed out their mining activities from atmospheric spectroscopy. Or much earlier, signs of agriculture. In which case they could be here...right about...just a sec, somebody's at the door....

My post was under the assumption it wasn't an alien lifeform. If that's what the person I responded to meant, then I see his/her point better. Still, if we finally found life, I'd prefer for them to be close rather than far.

Curiosity killed the cat, but I'd rather learn about the aliens (if they are indeed arriving on our doorstep soon) than know they're too far away for either of us to make it in time.

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

#33

Post by noiv »

zackya89 wrote: post #16
aarmenante wrote: post #4

> In the meantime, we would remind you that it's very, very unlikely that this strange flickering star has anything to do with aliens (and is even more exciting if it doesn't - because, hello new space phenomena!). I think aliens would be a little bit more exciting... Might just be me though.

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.

I hope one day title bashing turns into a global no-ads movement.

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

#34

Post by mjevans »

jerf wrote: post #22
lucb1e wrote: post #20

Earlier quoted context omitted.

Well whatever it is, we probably have 1000+ years to save ourselves right? If whatever caused it comes at us at 50% light speed, which sounds unlikely given how fast that already is, we'd still have 700 years. I'm pretty sure that if human's resources were suddenly all turned towards getting the hell out of here, we could certainly pull it off for a good part of the population in a few hundred years. Whether we'd eve…

"Well whatever it is, we probably have 1000+ years to save ourselves right?" No. That time has already passed. If we see signs that the star will go nova "in one year", we have one year, not 1481. The popular idea that we see "the past" in the sky is not really the best way to think about it. It is far more accurate to say that there is no such thing as "the" present, and what we see in the sky really is our present.…

From an intelligent life angle, what would really save us is that, aside from a number of planets to observe, we haven't really been all that interesting until the last 100-200 years; when we started actually emitting signs of intelligent life in to space.

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

#36

Post by david-given »

lucb1e wrote: post #31
jerf wrote: post #22

Earlier quoted context omitted.

"Well whatever it is, we probably have 1000+ years to save ourselves right?" No. That time has already passed. If we see signs that the star will go nova "in one year", we have one year, not 1481. The popular idea that we see "the past" in the sky is not really the best way to think about it. It is far more accurate to say that there is no such thing as "the" present, and what we see in the sky really is our present.…

So what's the risk if it turns supernova in one year? As you say, it's 1500 ly away, not You sound way more expert on this than me (I had no idea lightyears had a notation, ly, nor that supernovas are dangerous to us as far as 50ly away), so I'll assume what you say is accurate, but I still see no imminent threat. I'm also not suggesting we'd have the full 1481 years, since we don't see what's presently there but wha…

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 lot. It's 7500 light years away and I believe it's judged not to be a threat, although there may be ozone layer damage and it's probably not healthy to be an unshielded astronaut.

However supernovae appear to emit gamma ray bursts along their axes. These can travel very large distances. Eta Corina's isn't point our way, but Tabby's Star? Who knows. 1500 light years is basically point blank range for a GRB, so if one is coming our way that would be very bad news. Like, worse than mass extinction grade bad news.

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

#37

Post by tazjin »

antognini wrote: post #19
simcop2387 wrote: post #9

Earlier quoted context omitted.

Not entirely sure why, but I suspect because they haven't been able to determine if there's any lensing going on of the star that you'd expect to see if something like that entered the system. But I do believe that they'd see higher energy (x-ray, gamma?) bursts if it was removing material from the star which would lead to a different kind of variability. We know roughly what that should look like because of other bi…

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?

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

#38

Post by jerf »

david-given wrote: post #36
lucb1e wrote: post #31

Earlier quoted context omitted.

So what's the risk if it turns supernova in one year? As you say, it's 1500 ly away, not You sound way more expert on this than me (I had no idea lightyears had a notation, ly, nor that supernovas are dangerous to us as far as 50ly away), so I'll assume what you say is accurate, but I still see no imminent threat. I'm also not suggesting we'd have the full 1481 years, since we don't see what's presently there but wha…

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're right that I neglected gamma ray bursts. But it also doesn't seem like this star could be building up to that, since it requires conditions not evident there. (I'm just following up on my point, not implying that you claimed otherwise.)

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

#39

Post by b34r »

antognini wrote: post #19
simcop2387 wrote: post #9

Earlier quoted context omitted.

Not entirely sure why, but I suspect because they haven't been able to determine if there's any lensing going on of the star that you'd expect to see if something like that entered the system. But I do believe that they'd see higher energy (x-ray, gamma?) bursts if it was removing material from the star which would lead to a different kind of variability. We know roughly what that should look like because of other bi…

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…

Based on current science, there are many geometries of black holes. We can't speak in such absolutes.

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

#40

Post by civilian »

zackya89 wrote: post #16
aarmenante wrote: post #4

> In the meantime, we would remind you that it's very, very unlikely that this strange flickering star has anything to do with aliens (and is even more exciting if it doesn't - because, hello new space phenomena!). I think aliens would be a little bit more exciting... Might just be me though.

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...

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