Thus a large object could block 22% of the star's light while covering a much smaller percentage of its disk. This also explains why the dips in the light curve are pointed on the bottom, not flat.
I don't think so. Unless the hot pole and the obscuring object are very closely similar in angular size, then you'll not get a tight peak, but a flat-bottom or complex-bottom profile. It depends very closely on the intensity profile of the "hot pole", and the sharpness of the edge of the shading object.
causing its visible pole to slowly precess away from us. That would explain the gradual dimming.
Hmmm, that might work. The pole would actually have to be on the limb at the moment... and the progression wouldn't be linear with time.
(Unless they're all so addicted to video games that nobody want to have the lag of moving further from the server.)
For a Dyson thing the size of the Earth's orbit (actually, it's need to be a bit bigger, because this star is a bit brighter than the Sun), the server could be up to 16 light minutes away, if you did most of your signal travel by laser/ microwave. If you went round the outside, up to 25 light minutes.
So, these magnificent engineers who can design and build two things that we can't do ("replicators" ; Dyson "things"), haven't grasped the importance of designing in safety in their tools - which is something that we at least try.
If you're willing to believe in a civilization capable of building a Dyson sphere, how much more of a stretch is it to believe they could do it in a few centuries? ...
I mean, yeah, I have some idea of the energies involved, and I'm not sure I can envision a process that would run at that pace producing anything other than streams of plasma at gamma-ray temperatures.
You cast the problem clearly for yourself. Assembling some megastructure far smaller than a Dyson S(-phere/ -warm) would involve moving considerable masses of material from point A to point B, and changing it's momentum somewhere along that path. This is called "doing work".
Doing work produces heat. We don't see that heat. Problem.
I love it when people make judgements on the capabilities of an alien race. By definition, they are alien, so we can make no generalizations.
No?
They're 454 parsecs away. If they're exposed to different laws of physics to us, then we really don't understand the universe, and our technology is going to fall apart no £$^%$&%*$£ NO CARRIER
Oh, that hasn't happened. So, they have the same physics as us. Actually, the same chemistry as us (both are closely coupled by the spectroscopy of the star - same physics and same chemistry as us). So we've got a good knowledge of what their environment was 1500 years ago.
We've no reason to believe there is anything spectacularly different to our environment there. So the same general limits as apply to our environment apply to this environment. We're not seeing bucket-loads of magnetic monopole in our environment, so we're not going to see them naturally in that environment. While we do see these weird short-term spikes in the light pattern, the rest of the spectrum is fairly normal (though there is an intriguing and unusual secular dimming on a century-scale). More weirdly, the spikes are (by my count) 24 dips and only about 10 rises - which doesn't look like a MACHO transit light profile from an intermediate object (which wouldn't explain the secular variation anyway.
Thermodynamics doesn't work like that. If your organism doesn't absorb or emit electromagnetic radiation between 350 and 750 nm wavelength ("light") - at that point you're not talking about this star. This star DOES have something absorbing electromagnetic radiation between 350 and 750 nm wavelength ("light") - and does absorb between (say) 750 and 1500 nm wavelength ("heat"), then it will also be emitting at wavelengths greater than 1500nm.
Actually, strictly, any body at a temperature greater than absolute zero (which is unattainable), emits at all wavelengths, though the flux varies greatly with wavelength.
If they use something like an alcubierre metric based warp drive, then the gravitational fields around the craft will scatter the star's light into vectors that are no longer straight lines away from the star. This will result in the star's effective brightness being reduced.
... and in other directions, the light will be enhanced.
Actually, the maths for such space distortions was done - decades ago. For the MACHO project.
Get enough of them going in and out of the system routinely, and you will get the observed phenomenon.
Having just been looking at the data, I see 24 dips in the time period, and 10 spikes. So... something must be aimed pretty close to directly at us (or away, or in a cone of directions about our location). There would need to be some sort of unidirectional flow to produce that discrepancy in deviations from the norm.
>{?and your model accounts for the secular (long-term, century scale) dimming just how... ?
[W]hat if a star were bombarded with large inert bodies consisting of iron or other materials that would create inconsistent light output as those semisolid bodies materials moved about within the mixture?
A couple of years ago analysis of a star's light showed that it had recently had a large amount of debris similar to asteroids. I'm struggling to find the reference, I'm getting interference from the story that we're discussing at the moment. Can't find it. There's lots of reports of detecting silicates in the atmosphere of white dwarfs (e.g. http://arxiv.org/pdf/1007.2252... ; tracing forwards from that should get you a lot of stuff) But, no matter ; the spectral patterns caused by solid (silicate, asteroidal) bodies impacting stars is not a new topic, and there's plenty of evidence that the process is fairly well understood. Unless you're going to call the original researchers incompetent (which is not a good idea, unless you're actually working full time in that field yourself), it's safe to assume that they've covered this possibility, otherwise one or other of the people listed in the references of that 2010 review article would have raised the question.
We need to think outside the box,
Think outside the box as much as you like. But you are constrained by the evidence. In this case, TFP start it's abstract with "The star KIC 8462852 is a completely-ordinary F3 main sequence star," so your scenario doesn't fit the reality. It might be interesting for some other star, but not this one.
You're thinking of nuclear "waste" and other unstable mid-table elements - those will decay substantially in mere thousands of years
Even eka-Manganese (as Mendeleev named it's placeholder in the periodic table ; technetium otherwise ; the lowest mass element with no naturally occurring stable isotopes) has isotopes with half-lives in the 200,000 to 4,000,000 year range, which would survive a 100,000 year journey without problems.
Actually, you'd want to be careful what isotopes you used. The presence of short-lived isotopes (say 150,000 years) would constrain the time of flight of the attack.
have it course-correct in 1000 years and then securely delete the information on the computer that did the course correction (so that the computer's function can't be reverse-engineered)
I think that impacting a surface at dozens of kilometres per second counts as "secure delete." Your computer is going to be vapourised on impact.
No, any alien capable of building a Dyson sphere would have eliminated all asteroids capable of causing problems long before the megastructure got big enough
This is a trope that has appeared in SF. To demonstrate "would have" you'd need to deal with both in-system debris - material in orbit around the star that you're encapsulating - and have an infallible system for dealing with random incoming debris from outside the star's orbit. The one is a big deal to achieve ; the second is something that would require detailed continuous observation with infallible hair-trigger responses. Which is going to cost a lot.
How would we, today detect an incoming extra-solar asteroid? Well, we could rely on a ring of telescopes in the Kuiper Belt - except that our hypothetical megastructure has cleared out their Kuiper Belt, because it's part of the problem. Plus there's nothing to prevent the incoming projectile from coming in from any direction. But you can build your big telescopes in the Kuiper Belt and have them look towards the poles ; you'd need interception hardware to be pre-placed in a range of high-angle orbits, but that's small beer to a Dyson-building civilisation. Now, you complete your Dyson - be it Sphere or Swarm - and all of a sudden you've trapped 90% plus of the light leaving your star, so it's suddenly a LOT harder to see anything out there that's coming in.
Of course, all that hardware will need maintenance. Or, if it goes off-line, it'll become a uncontrolled debris itself, adding to the threat.
I don't see Dyson spheres being any great use for anything other than getting thermonuclear power without having to build your own fusion reactor.
When they say we have enough nukes to destroy the earth many times over they don't mean blow it into tiny pieces just destroy all life on earth.
Hmmm. "Destroy all life on Earth"... tricky. Even with our whole arsenal, we're pretty unlikely to get everything even on the surface of the Earth. Unless you count the surface of the oceans as "the surface", which neglects the whole bottom several kilometres of the oceans. There's representatives of every phylum other than land plants there, and you're going to have to work hard to annihilate all stored/ buried seeds on land.
You could probably wipe the land clean pretty fast, but to actually destroy all marine life (and all life in thicker soils) is a much harder task.
I've always been suspicious of the "deep biosphere" idea, but there certainly is life in rocks down to several kilometres depth (I've bagged the samples myself). So that's another excavation target you'd need.
... is the Hawking is doing this year's Reith Lectures. That should mean a 4 to 6 hour set of lectures for an intelligent audience which he has had months to prepare.
IF IBE is so obviously flawed, but it is being deployed for the use of hogh profile and high value targets, then this makes it a highly desirable target for hacking.
Firstly, the discovery of such an incriminating file would be kept EXTREMELY quiet by the investigation team. Possession of the file would then be "guilty knowledge," and action for further investigation.
Then, you ant to look for copies of the file in circulation. This is what virus scanners - at both individual computer AND at the gateways of large service providers are for, and do. So, either through a tame person at major virus vendors, or by crafting a version of the file that contains a piece of malware, you "inform" the virus industry of this particular file, with this particular fingerprint / set of heuristics, etc. Get those into the regular updates of the major anti-virus providers, and you should get alerts from the existing systems if the file is passing around.
And you still don't announce it. This information comes out at trial, if then.
The report isn't very clear on this, but the connection is this :
It isn't known when the first humans got to America (nor is it known if they left any descendents), but it was before about 13000 years before present. The record of human fossils in the parts of NE Asia near to North America is very, very sparse. This find shows that humans of about 45000 years ago had the behaviours and technologies necessary to survive at least part of the year at 72 degrees north, and if they could do it at the Yenisei, there's nothing in particular to stop them from doing it further East, towards America.
Oh, it's an AC - they can't comment back. But I hope this clarifies things a bit.
Bone that is alive - or recently dead - cuts under the knife in a different way to bone that has been dead for days or longer. It's a basic of the study of bones and wounds, which has obvious interest to the police. Not just your "is this that missing hooker?" local Police Department, but also those looking at (alleged) mass graves from the Bosnian/ Somali/ Sudanese... conflicts.
If you're hearing that said, then you need to get a less-biased quote mine. In the last several thousand years, averaged over the planet, it has not been hotter. But in the longer term (looking back to e.g. the PETM), it has been hotter, consequent on dumping carbon into the atmosphere at rates that we are exceeding these days. Those climate excursions took in excess of 100,000 years to turn around, which is why they mark a mass extinction.
For mammoths - and many other grazing animals, the problem is not temperature, but whether or not they can get at food under the snow.
When the Arctic was colder, the moisture would have frozen out of the air further out in the margins (Scandanavia, Korea, Kamchatka) leaving Central Siberia very cold, but dry. At which point, the long daylight hours of the summer can produce relatively large amounts of growth which can be eaten in the winter - if it's not buried under the snow.
Oooh, sorry, cremation is external application of heat, typically burning propane, but in some cases you can use oil or wood.
I remember when the Ebola crisis was burning around in the area (I was working in West Africa at the time) and people were wondering why bodies were being buried in bleach-soaked body bags, instead of being burned.
The WHO's guidelines call for about 100kg of wood per corpse to cremate them safely, while the body bag and bleach weighs about 10kg. That makes a difference when you have hundreds of bodies to deal with. 200 bodies is a full lorry load of wood, which if you'renot got any access better than a dirt road, is a LOT.
One of the very first "projects" reported for many of the first generation of computers was actually the production of tables of pre-calculated range, windage etc corrections for artillery aiming. I've heard that story for the Manchester Colossus, and several others. It might be a credible cover story, or it might be because checking the output is probably relatively simple.
That was in the late 1940s and early 1950s. At that time the rocket people were re-implementing the V-programmes, looking at novel propellants (if you can find a copy of "Ignition", invest a day in reading it. Any book where the frontispiece has a "before" and "after" photograph where you need to use distant trees to align "before" and "after" is about an exciting, dynamic field of study). Design of new rocket systems didn't really kick off until they proved that nuclear subs could hide under Arctic ice for months AND surface...
They didn't invent this stuff for going to the stars - they invented it for blowing human beings into pieces.
Slashdot Mirror
Because the dimmings are (1) too deep, (2) too irregular and (3) there's that pesky secular (century+) change too.
I don't think so. Unless the hot pole and the obscuring object are very closely similar in angular size, then you'll not get a tight peak, but a flat-bottom or complex-bottom profile. It depends very closely on the intensity profile of the "hot pole", and the sharpness of the edge of the shading object.
Hmmm, that might work. The pole would actually have to be on the limb at the moment ... and the progression wouldn't be linear with time.
For a Dyson thing the size of the Earth's orbit (actually, it's need to be a bit bigger, because this star is a bit brighter than the Sun), the server could be up to 16 light minutes away, if you did most of your signal travel by laser/ microwave. If you went round the outside, up to 25 light minutes.
Lag is not an appropriate explanation.
Hmm, there's a contradiction in there somewhere.
You cast the problem clearly for yourself. Assembling some megastructure far smaller than a Dyson S(-phere/ -warm) would involve moving considerable masses of material from point A to point B, and changing it's momentum somewhere along that path. This is called "doing work".
Doing work produces heat. We don't see that heat. Problem.
No?
They're 454 parsecs away. If they're exposed to different laws of physics to us, then we really don't understand the universe, and our technology is going to fall apart no £$^%$&%*$£ NO CARRIER
Oh, that hasn't happened. So, they have the same physics as us. Actually, the same chemistry as us (both are closely coupled by the spectroscopy of the star - same physics and same chemistry as us). So we've got a good knowledge of what their environment was 1500 years ago.
We've no reason to believe there is anything spectacularly different to our environment there. So the same general limits as apply to our environment apply to this environment. We're not seeing bucket-loads of magnetic monopole in our environment, so we're not going to see them naturally in that environment. While we do see these weird short-term spikes in the light pattern, the rest of the spectrum is fairly normal (though there is an intriguing and unusual secular dimming on a century-scale). More weirdly, the spikes are (by my count) 24 dips and only about 10 rises - which doesn't look like a MACHO transit light profile from an intermediate object (which wouldn't explain the secular variation anyway.
It's very peculiar. It's also tea time for me!
That's the question.
Actually, strictly, any body at a temperature greater than absolute zero (which is unattainable), emits at all wavelengths, though the flux varies greatly with wavelength.
Actually, the maths for such space distortions was done - decades ago. For the MACHO project.
Having just been looking at the data, I see 24 dips in the time period, and 10 spikes. So ... something must be aimed pretty close to directly at us (or away, or in a cone of directions about our location). There would need to be some sort of unidirectional flow to produce that discrepancy in deviations from the norm.
>{?and your model accounts for the secular (long-term, century scale) dimming just how ... ?
The sources that give him the answers he wants.
A couple of years ago analysis of a star's light showed that it had recently had a large amount of debris similar to asteroids. I'm struggling to find the reference, I'm getting interference from the story that we're discussing at the moment. Can't find it. There's lots of reports of detecting silicates in the atmosphere of white dwarfs (e.g. http://arxiv.org/pdf/1007.2252... ; tracing forwards from that should get you a lot of stuff) But, no matter ; the spectral patterns caused by solid (silicate, asteroidal) bodies impacting stars is not a new topic, and there's plenty of evidence that the process is fairly well understood. Unless you're going to call the original researchers incompetent (which is not a good idea, unless you're actually working full time in that field yourself), it's safe to assume that they've covered this possibility, otherwise one or other of the people listed in the references of that 2010 review article would have raised the question.
Think outside the box as much as you like. But you are constrained by the evidence. In this case, TFP start it's abstract with "The star KIC 8462852 is a completely-ordinary F3 main sequence star," so your scenario doesn't fit the reality. It might be interesting for some other star, but not this one.
Even eka-Manganese (as Mendeleev named it's placeholder in the periodic table ; technetium otherwise ; the lowest mass element with no naturally occurring stable isotopes) has isotopes with half-lives in the 200,000 to 4,000,000 year range, which would survive a 100,000 year journey without problems.
Actually, you'd want to be careful what isotopes you used. The presence of short-lived isotopes (say 150,000 years) would constrain the time of flight of the attack.
I think that impacting a surface at dozens of kilometres per second counts as "secure delete." Your computer is going to be vapourised on impact.
This is a trope that has appeared in SF. To demonstrate "would have" you'd need to deal with both in-system debris - material in orbit around the star that you're encapsulating - and have an infallible system for dealing with random incoming debris from outside the star's orbit. The one is a big deal to achieve ; the second is something that would require detailed continuous observation with infallible hair-trigger responses. Which is going to cost a lot.
How would we, today detect an incoming extra-solar asteroid? Well, we could rely on a ring of telescopes in the Kuiper Belt - except that our hypothetical megastructure has cleared out their Kuiper Belt, because it's part of the problem. Plus there's nothing to prevent the incoming projectile from coming in from any direction. But you can build your big telescopes in the Kuiper Belt and have them look towards the poles ; you'd need interception hardware to be pre-placed in a range of high-angle orbits, but that's small beer to a Dyson-building civilisation. Now, you complete your Dyson - be it Sphere or Swarm - and all of a sudden you've trapped 90% plus of the light leaving your star, so it's suddenly a LOT harder to see anything out there that's coming in.
Of course, all that hardware will need maintenance. Or, if it goes off-line, it'll become a uncontrolled debris itself, adding to the threat.
I don't see Dyson spheres being any great use for anything other than getting thermonuclear power without having to build your own fusion reactor.
Hmmm. "Destroy all life on Earth" ... tricky. Even with our whole arsenal, we're pretty unlikely to get everything even on the surface of the Earth. Unless you count the surface of the oceans as "the surface", which neglects the whole bottom several kilometres of the oceans. There's representatives of every phylum other than land plants there, and you're going to have to work hard to annihilate all stored/ buried seeds on land.
You could probably wipe the land clean pretty fast, but to actually destroy all marine life (and all life in thicker soils) is a much harder task.
I've always been suspicious of the "deep biosphere" idea, but there certainly is life in rocks down to several kilometres depth (I've bagged the samples myself). So that's another excavation target you'd need.
Prepare to get it in chunks over the next month.
What, you want it now? Tough.
No?
Then, you ant to look for copies of the file in circulation. This is what virus scanners - at both individual computer AND at the gateways of large service providers are for, and do. So, either through a tame person at major virus vendors, or by crafting a version of the file that contains a piece of malware, you "inform" the virus industry of this particular file, with this particular fingerprint / set of heuristics, etc. Get those into the regular updates of the major anti-virus providers, and you should get alerts from the existing systems if the file is passing around.
And you still don't announce it. This information comes out at trial, if then.
It isn't known when the first humans got to America (nor is it known if they left any descendents), but it was before about 13000 years before present. The record of human fossils in the parts of NE Asia near to North America is very, very sparse. This find shows that humans of about 45000 years ago had the behaviours and technologies necessary to survive at least part of the year at 72 degrees north, and if they could do it at the Yenisei, there's nothing in particular to stop them from doing it further East, towards America.
Oh, it's an AC - they can't comment back. But I hope this clarifies things a bit.
Bone that is alive - or recently dead - cuts under the knife in a different way to bone that has been dead for days or longer. It's a basic of the study of bones and wounds, which has obvious interest to the police. Not just your "is this that missing hooker?" local Police Department, but also those looking at (alleged) mass graves from the Bosnian/ Somali/ Sudanese ... conflicts.
If you're hearing that said, then you need to get a less-biased quote mine. In the last several thousand years, averaged over the planet, it has not been hotter. But in the longer term (looking back to e.g. the PETM), it has been hotter, consequent on dumping carbon into the atmosphere at rates that we are exceeding these days. Those climate excursions took in excess of 100,000 years to turn around, which is why they mark a mass extinction.
Why do you think that?
For mammoths - and many other grazing animals, the problem is not temperature, but whether or not they can get at food under the snow.
When the Arctic was colder, the moisture would have frozen out of the air further out in the margins (Scandanavia, Korea, Kamchatka) leaving Central Siberia very cold, but dry. At which point, the long daylight hours of the summer can produce relatively large amounts of growth which can be eaten in the winter - if it's not buried under the snow.
(I had a friend do that - about 20,000 plants in a commercial greenhouse across the river from Queen Brenda's house. Got caught, which was a bummer.)
I remember when the Ebola crisis was burning around in the area (I was working in West Africa at the time) and people were wondering why bodies were being buried in bleach-soaked body bags, instead of being burned.
The WHO's guidelines call for about 100kg of wood per corpse to cremate them safely, while the body bag and bleach weighs about 10kg. That makes a difference when you have hundreds of bodies to deal with. 200 bodies is a full lorry load of wood, which if you'renot got any access better than a dirt road, is a LOT.
That was in the late 1940s and early 1950s. At that time the rocket people were re-implementing the V-programmes, looking at novel propellants (if you can find a copy of "Ignition", invest a day in reading it. Any book where the frontispiece has a "before" and "after" photograph where you need to use distant trees to align "before" and "after" is about an exciting, dynamic field of study). Design of new rocket systems didn't really kick off until they proved that nuclear subs could hide under Arctic ice for months AND surface ...
They didn't invent this stuff for going to the stars - they invented it for blowing human beings into pieces.