Any civilization that is advanced enough to build structures big enough to block a measurable portion of it's star's light is one I hope never discovers us.

still think Klingons or Dominians they might be?!
;)

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non-profit org. Play4Life in Zagreb, Croatia, EU

Any civilization that is advanced enough to build structures big enough to block a measurable portion of it's star's light is one I hope never discovers us.

still think Klingons or Dominians they might be?!
;)

No, more like the Borg :)

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Bob DeWoody

My motto: Never do today what you can put off until tomorrow as it may not be required. This no longer applies in light of current events.

Still trying to determine if it's reasonable that comet fragments could dim Tabby's Star by up to 22 percent. Found a video of a comet passing in front of the Sun in 2011. The comet can barely be seen. No dimming can be discerned. What one can see of it is that it's glowing gasses brighten the surface of the Sun.

If a comet can be expected to emit enough light to make up for any dimming caused by its dust, how can comet fragments dim Tabby's Star, especially to such a high degree? A link to the video of the comet:
http://www.eurekalert.org/multimedia/pub/39952.php

Still trying to determine if it's reasonable that comet fragments could dim Tabby's Star by up to 22 percent. Found a video of a comet passing in front of the Sun in 2011. The comet can barely be seen. No dimming can be discerned. What one can see of it is that it's glowing gasses brighten the surface of the Sun.

If a comet can be expected to emit enough light to make up for any dimming caused by its dust, how can comet fragments dim Tabby's Star, especially to such a high degree? A link to the video of the comet:
http://www.eurekalert.org/multimedia/pub/39952.php

& Tabby's star is 50% larger than the Sun!

whatever it is, it's a BIG!
;)

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non-profit org. Play4Life in Zagreb, Croatia, EU

A star 50% larger than the sun is still a relatively small star. Betelgeuse on the other hand ai 700 times the size of the sun. Now that's big

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Bob DeWoody

My motto: Never do today what you can put off until tomorrow as it may not be required. This no longer applies in light of current events.

A star 50% larger than the sun is still a relatively small star. Betelgeuse on the other hand ai 700 times the size of the sun. Now that's big

yeah, I know that...

but colleague has put a video of a Sun with asteroid...on which asteroid is barely visible! ;)

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non-profit org. Play4Life in Zagreb, Croatia, EU

After re-reading your previous post I realised you were referring to the object or objects that are causing the dimming of the star. My bad.

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Bob DeWoody

My motto: Never do today what you can put off until tomorrow as it may not be required. This no longer applies in light of current events.

Or... that passing star that's supposed to have pulled all those comets from their Oort Cloud pulled something much larger instead, and that object then collided with a gas giant orbiting Tabby's Star or passed close enough to one to tear it apart.
I'm just having trouble wrapping my head around the sheer volume required for a cloud of comets to block 22% of the light from that star. If what we've observed in our own system is any guide we'd have to be talking about millions of comets in that cloud, no?

Or... that passing star that's supposed to have pulled all those comets from their Oort Cloud pulled something much larger instead, and that object then collided with a gas giant orbiting Tabby's Star or passed close enough to one to tear it apart.
I'm just having trouble wrapping my head around the sheer volume required for a cloud of comets to block 22% of the light from that star. If what we've observed in our own system is any guide we'd have to be talking about millions of comets in that cloud, no?

nope!

if that were the case, IR would be "totally in red zone"...& they observed Tabby star in IR!
;)

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non-profit org. Play4Life in Zagreb, Croatia, EU

The destruction of a planet-sized mass would leave a good deal of dust behind. This has been looked for repeatedly in the Tabby's Star system, and should have been detectable, but was not found.
Disrupted comets were selected as the one known natural phenomenon that was at least conceivable, given the available evidence. That's not the same as saying that comets are a probable explanation.
It's often been observed that comets have the advantage of being much more likely than the non-natural alternative which has been discussed. Frankly, I don't see how such a comparison can be made. We know nothing about the existence, number, or distribution of ET civilizations in the galaxy.
If they happen to be common, or if one civilization exists throughout our galaxy ( a possibility suggested by the reasoning behind the Fermi paradox) then megastructures of some sort might be more probable than a remarkably dense cluster of comet fragments.

Or... that passing star that's supposed to have pulled all those comets from their Oort Cloud pulled something much larger instead, and that object then collided with a gas giant orbiting Tabby's Star or passed close enough to one to tear it apart.
I'm just having trouble wrapping my head around the sheer volume required for a cloud of comets to block 22% of the light from that star. If what we've observed in our own system is any guide we'd have to be talking about millions of comets in that cloud, no?

nope!

if that were the case, IR would be "totally in red zone"...& they observed Tabby star in IR!
;)

From our perspective we have never observed the sun down the length of a comet's tail.

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The destruction of a planet-sized mass would leave a good deal of dust behind. This has been looked for repeatedly in the Tabby's Star system, and should have been detectable, but was not found.
Disrupted comets were selected as the one known natural phenomenon that was at least conceivable, given the available evidence. That's not the same as saying that comets are a probable explanation.
It's often been observed that comets have the advantage of being much more likely than the non-natural alternative which has been discussed. Frankly, I don't see how such a comparison can be made. We know nothing about the existence, number, or distribution of ET civilizations in the galaxy.
If they happen to be common, or if one civilization exists throughout our galaxy ( a possibility suggested by the reasoning behind the Fermi paradox) then megastructures of some sort might be more probable than a remarkably dense cluster of comet fragments.

again, Tabby star was watched in IR spectrum...if such a "destruction event" was happened, then a residual heat of the impact would show on IR!

no IR other than Sun, so no residual heat from planet-size collision!


also, their civilization & technology was not visible on IR...so either they don't produce so much power & waste...or they are not detectable over 1500ly away in comparison to their Tabby star!
;)

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non-profit org. Play4Life in Zagreb, Croatia, EU

Intriguing new developments on Tabby's Star. The records of observations of this star from 1890 to 1989 were gone over. During this 99 years, the star dimmed by a very substantial 16 percent. This is unprecedented in an F star on the main sequence, as Tabby's star is held to be.
If we were to hold to the current comet explanation for the stars dimming, there would have had to have been about 648,000 giant comets, each about 200 kilometers (120 miles) in diameter passing in front of this star, with their numbers increasing over time to account for consistently increased dimming.

Alternatively, we could be watching a Dyson swarm in the process of being built, with 16.3 percent more of the star's light collected, and so blocked from our view, in the course of a century. Because of the star's distance, this was actually happening about 1500 years ago.

Link to a scientific paper on this, below:

http://arxiv.org/abs/1601.03256

Let's wait for a while...after Aug-Sep 2016 we might be wiser! Even more in 2017...like I've posted earlier!
;)

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non-profit org. Play4Life in Zagreb, Croatia, EU

Story Update:

Dimming star remains mystery, but it's likely not caused by comets


(CNN)Remember that space anomaly of the dimming star that had everyone crying "aliens"? Well, it's still as mysterious as ever.

Theories surrounding the star system KIC 8462852, also known as Tabby's Star, ranged from comets to an "alien megastructure" after the online astronomy crowdsourcing site Planet Hunter discovered an unusual light fluctuation in the star system a few years ago.

http://www.cnn.com/2016/01/16/us/space-anomaly-remains-mystery/

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They wanted to wait until the star had another substantial dip in brightness, then analyze the light with the spectroscope. If no signs of dust were found, then larger objects would be assumed to be responsible.

Well, it now appears that Tabby's Star dimmed steadily for over a century. It's current brightness reportedly follows the declining trend established for the years 1890 to 1989. The searches for dust in that star system found none.

If we can now assume that larger objects are responsible for the dimming of this star, how large would they be? The two major short term dips in brightness amounted to 15 and 22 percent. That suggests objects about 550,000 to 700,000 miles in diameter.
Natural objects of those sizes would be stars, and would presumably shine conspicuously. We see no such stars near KIC 8462852, although the searches were sensitive enough to turn up a distant red dwarf companion star.

If they are an advanced species making a Dyson sphere...it would also indicate, most probably, an isolation type of advanced civilization...so any indication of them, if they are possible to hear - would be very nice to know more about them...of course, if that really is aliens out there?!

I'd be more cautions from now on...especial NOT sending them ANY signal!
we're seeing a Dyson sphere being built about 1.5 millennium ago...image what they do now?!
;)

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non-profit org. Play4Life in Zagreb, Croatia, EU

If they are an advanced species making a Dyson sphere.

we're seeing a Dyson sphere being built about 1.5 millennium ago

Quite a big jump from "if" to "we ARE"

I'd be more cautions from now on..

Yes I agree :-)

we ARE seeing SOMETHING...that we can't explain!

so far, all other hypothesis have been abandoned...one by one...so:

;)

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non-profit org. Play4Life in Zagreb, Croatia, EU

There are more things in the sky than those predicted by your philosophy (with excuses to Shakespeare). Witness the new super supernova for which there is no explanation.
Tullio

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No mid-infrared radiation, expected to be radiated by a Dyson Swarm as waste heat, has been detected. Some very energy efficient technology would need to be supposed.
Its been suggested that a Dyson swarm might have multiple layers of energy extraction, each leaving the energy level lower. This would render the outer layer with a temperature not far above that of open space. This would presumably not be readily detectable.