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  1. Standard member sonhouse
    Fast and Curious
    23 Jan '16 21:32
    http://arstechnica.co.uk/science/2016/01/stars-bizarre-optical-antics-go-back-at-least-a-century/

    Now they can see this is not a new thing, dimming going on for a century at least. Probably a LOT longer than that.

    Mystery deepens. It can't be comets. And certainly not aliens building a Dyson sphere.
  2. 24 Jan '16 06:34
    Originally posted by sonhouse
    And certainly not aliens building a Dyson sphere.
    Why not? The only excuse for ruling that out in the article is that they would have to be building it quite fast (over the course of a century or more). Anyone capable of building a Dyson sphere might also be capable of fast construction.
  3. Standard member sonhouse
    Fast and Curious
    24 Jan '16 17:09
    Originally posted by twhitehead
    Why not? The only excuse for ruling that out in the article is that they would have to be building it quite fast (over the course of a century or more). Anyone capable of building a Dyson sphere might also be capable of fast construction.
    It wasn't the speed I was thinking of as far as problems with that concept. I just thought if they were building a sphere, the dimming wouldn't have that kind of random pattern. Presumably it would be in some kind of orbit, I would think it would have to revolve around its sun so that looked to me like it would have to have a periodic light intensity pattern not that on off on wait 40 years, on, off, wait 12 years etc.
  4. 24 Jan '16 17:24
    Originally posted by sonhouse
    It wasn't the speed I was thinking of as far as problems with that concept. I just thought if they were building a sphere, the dimming wouldn't have that kind of random pattern. Presumably it would be in some kind of orbit, I would think it would have to revolve around its sun so that looked to me like it would have to have a periodic light intensity pattern not that on off on wait 40 years, on, off, wait 12 years etc.
    Given that we know nothing about what some alien civilization might be doing with their Dyson sphere it seems rather premature to make any conclusions about it.

    There is no reason to think it is a complete sphere. It could be something as simple as a very large solar sail type structure. And they could be moving it around or adjusting it over time depending on what it is being used for all resulting in a different amount of radiation coming our way. It just seems you are ruling it out based on your own expectations not on what is actually possible. That is like seeing an alien spacecraft and then saying: it can't be a spacecraft, it doesn't have wings. I would have made wings.
  5. Standard member sonhouse
    Fast and Curious
    24 Jan '16 17:38 / 2 edits
    Originally posted by twhitehead
    Given that we know nothing about what some alien civilization might be doing with their Dyson sphere it seems rather premature to make any conclusions about it.

    There is no reason to think it is a complete sphere. It could be something as simple as a very large solar sail type structure. And they could be moving it around or adjusting it over time depe ...[text shortened]... craft and then saying: it can't be a spacecraft, it doesn't have wings. I would have made wings.
    Very VERY large structure for sure. I wonder what size telescope it will take to suss out just what is going on? 1200 light years is pretty close on a galactic scale, since the milky way is 200,000 light years across. Not going to be going there any time soon though

    Assuming the star is 1.6 million km diameter, at that distance it works out to an arc second size of 18.5 MICRO arc seconds. Taking Hubble to have a resolution of 50 milli-arc seconds at a mirror size of 2 meters, 1000 X bigger would still leave it at 50 micro arc seconds so it might take 10000X bigger or a mirror effective size of 20,000 meters or 20 km. It could be done but nobody is going to make a single mirror that large so it would have to be an array of smaller mirrors with separation of 20 km like a dozen Hubble's scattered across a 20 Km area. Or something similar. Won't be seeing THAT this century either.

    One problem getting higher resolution that way is they are pushing the limits already as to how far the scopes can be separated. I think max right now is less than a km.

    It might be able to be made on the ground but it sure would not be cheap. Billions I would expect even if they can extend the array size to 20 km like that. I think the furthest separation now is about 300 meters or so, which would max out at about 400 micro-arc seconds.
  6. 24 Jan '16 19:42
    Originally posted by sonhouse
    I wonder what size telescope it will take to suss out just what is going on?
    One does not need clear focused images to suss things out. Almost all astronomy is based on what are effectively point sources to telescopes. Instead there is an awful lot of information available in the spectrum and intensity of light.

    For this particular case I think the solution will be to survey all closer stars and see if there are any others with similar characteristics that we can examine a bit more easily. Alternatively if we find many such stars far away we might find a pattern in the behaviours. I certainly doubt that the main breakthroughs will come from massive telescopes.
  7. Standard member sonhouse
    Fast and Curious
    25 Jan '16 21:15 / 1 edit
    Originally posted by twhitehead
    One does not need clear focused images to suss things out. Almost all astronomy is based on what are effectively point sources to telescopes. Instead there is an awful lot of information available in the spectrum and intensity of light.

    For this particular case I think the solution will be to survey all closer stars and see if there are any others with ...[text shortened]... the behaviours. I certainly doubt that the main breakthroughs will come from massive telescopes.
    I wonder if radio telescopes have gotten involved with this study yet? When a multitude of these devices spread out over the entire Earth's surface and some in space, the resolution of the entire array is much better than any optical scope, multiple or no.

    The astronomers studying that star would have to pitch a nice case to get observing
    time though.

    I think it will require a massive increase in res power of whatever we use, perhaps to analyse what is going on very close to the star, are there clouds of cold dense gas in that system? I don't think we can tell based on what we see with scopes just yet.

    Radio telescopes are much better at sniffing out cold gas in the interstellar medium.
  8. 08 Feb '16 23:14
    Originally posted by sonhouse
    http://arstechnica.co.uk/science/2016/01/stars-bizarre-optical-antics-go-back-at-least-a-century/

    Now they can see this is not a new thing, dimming going on for a century at least. Probably a LOT longer than that.

    Mystery deepens. It can't be comets. And certainly not aliens building a Dyson sphere.
    That would be the headquarters for the DNC.
  9. Standard member sonhouse
    Fast and Curious
    09 Feb '16 23:33
    Originally posted by whodey
    That would be the headquarters for the DNC.
    Is this Republican humor or Libertarian? Or perhaps a play on Digital Numerical Control which is what most machinists use today?