Discussion in 'Science, Tech, & Space Exploration' started by nivek, Aug 2, 2018.

1. CasualBystanderCelestial

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Well... That's just speculation.

If you have a giant generator to feed the radio you just need to down convert prompt radiation to the correct frequency.

A Chicxulub sized asteroid (about 15 kilometers) would give enough power for about 8 bursts.

2. 3FEL9Islander

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Heh, Yeah I have to agree with you on that. Didn't understand at first just how powerful they were.
But I still dont understand how the determine the actual output of the FRBs since they are not exactly sure how far away they are from earth.

Free-space path loss - Wikipedia

"the power density due to path loss by spreading of the electromagnetic energy yielding loss proportional to the square of distance"

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4. Thomas R. MorrisonDowning petulant pilots with logic since 2018

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No. AAVs are commonly known to be devoid of emissions; it's a key performance characteristic and has been for over 70 years.

You keep ignoring the fact that it takes an equal magnitude of antimatter to convert matter into energy. I already showed you the math - producing 200 gigatons of antimatter is an unthinkably ambitious project.

The gravitational binding energy of the Earth is about 2.24 x 10^32 Joules. A perfectly efficient 400 gigaton matter/antimatter bomb yields about 3.3074 x 10^31 J. So a detonation of that magnitude would be enough to blow the Earth into small chunks - it's within an order of magnitude of blowing the entire planet into dust.

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5. CasualBystanderCelestial

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Yup - that is correct, given Earth technology.

The signals come from 3 billion light years away and would have taken about 6 billion years to get here.

If someone dyson sphered a sun - they could easily power the transmitter.

But all you really have to do is neutralize the short range bonding forces and about 99.9999% of the mass of matter converts to energy as the nucleus unbinds into a shower of quarks.

The side benefit is you can collect the electrons and have a huge negative charge source.

Several ways they could collect the energy.

Actually annihilating matter is sort of hard and looks like a zero sum game based on our current knowledge.

6. Thomas R. MorrisonDowning petulant pilots with logic since 2018

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No we're talking about a fundamental law of physics here - the conservation of baryon number. It's not just a technological issue.

What? No. If a signal comes from 3 billion LYs away, it takes 3 billion years for it to get here.

Sure, but since a typical star like ours possesses >99.8% of the mass of the system, a civilization would have to cannibalize an awful lots of planets in order to build a Dyson sphere. I doubt that anyone would go to the trouble. Because long before a civilization would have the capability of absorbing many entire planetary systems for raw materials, they'd be able to build their own fusion reactors.

No, it doesn't work like that. Quarks can't exist alone, for one thing. Due to the asymptotic freedom of quantum chromodynamics, it actually takes an increasing level of energy to remove quarks from the nucleus, until you get into pair production territory. So it costs energy to overcome the strong force - there's no magical way to just "turn off" the nuclear strong force.

Removing electrons requires overcoming the electrostatic charge interaction with the nucleus. There's no way to just "turn off" that field either.

There doesn't appear to be any information in these signals. So they're almost certainly a naturally occurring event, not a technological one.

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7. 3FEL9Islander

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Expansion of the universe , or signal scattering ?

8. 3FEL9Islander

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LoL Pure fantasy

9. CasualBystanderCelestial

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It is actually impure fantasy.

10. CasualBystanderCelestial

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The fabric universe according to scientists, is stretching like a piece of rubber.

This redshifts light, much like stretching a spring reduces the turns per inch.

11. 3FEL9Islander

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Someone told me its like watching piece a doe with raisins on top ferment. The individual raisins are unaffected but the distance between them increases.

12. CasualBystanderCelestial

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The muffin analogy works. The raisins inside the muffin are further apart too.

Perhaps the universe is fermenting...

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13. CasualBystanderCelestial

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Well... no.

Expansion of the universe - Wikipedia

Using their example of a quasar 4 billion LY away.

1. The light was emitted from 4 billion LY away.
2. The light traveled 13 billion LY. This
3. The quasar is now 28 billion LY away and if the expansion of the universe was instantaneously stopped right now, light from the quasar would take 28 billion years to get here, and not be redshifted at all.

Last edited: Aug 9, 2018
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Yeah, I gotta back Casual on this, A Dyson sphere while theoretical is more than a fantasy, There is a scale called the Kardashev scale that proposes an order to technological advancement in possible extraterrestrial development, Kardashev scale - Wikipedia

And a Dyson sphere on this Scale, Is a Type 2 civilization achievement. In fact, The Idea of the Kardashev scale depends on a civilizations ability to harness the power of stars, A Dyson sphere while never discovered, Is all but Expected to exist in the vastness of the cosmos, And in the eyes of most astrophysicists.

15. Thomas R. MorrisonDowning petulant pilots with logic since 2018

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When astronomers talk about cosmological-scale observations to the press, they don’t use proper distance or comoving distance, they use lookback time as a measure of distance, like we see at this NASA page:

“Current observations suggest that the Universe is about 13.7 billion years old. We know that light takes time to travel, so that if we observe an object that is 13 billion light years away, then that light has been traveling towards us for 13 billion years. Essentially, we are seeing that object as it appeared 13 billion years ago.”
The Cosmic Distance Scale

"Suppose we use the parsec definition above. That is, based upon the light we currently see, how far away is a quasar with redshift z = 6? Another way to say this would be "How far away was the quasar when the light left it?" This turns out to be about 1.2 billion parsecs. It's tempting to convert this to light years, and thus say it was about 3.9 billion light years away, but this is misleading. Because the cosmos was expanding as the light traveled to us, it actually took the light about 12.8 billion years to reach us. So its light travel time distance is actually 12.8 billion light years. This is the most common "distance" used, since it's easy to compare with the age of the light."
How We Define Distance In An Expanding Universe

Otherwise they'd have to specify either A.) the distance at the time the light was emitted, or B.) the distance to the object now in comoving coordinates. So instead they use the time-of-flight, which is the lookback time, because in this example we're seeing the object as it was 3 billion years ago, i.e. the light has traveled a distance of 3 billion light-years. That's a lot easier than trying to explain either the distance to the object when the light was emitted, which was closer than it is now, or the comoving distance, which we can only infer, and which would only confuse people because the most distant objects are presently much further away in light-years than the age of the universe.

This is why most astronomers grit their teeth over the fact that pop science writers refuse to use the cosmological redshift factor z instead using lookback time as a measure of distance: the redshift is the only real observable, and any distance scale is only a derivative of that.

No, lol - "most astrophysicists" don't expect Dyson spheres to exist. The engineering issues are enormous and any civilization capable of building such a monstrous thing would've produced their own fusion reactors long before that point in their technological evolution...or probably found an altogether more useful source of energy than fusion.

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Pages are loading really slow for me this morning, I don't know why I think it's my router,

Hmm, I still need to get the star trek out of my physics, But, Wouldn't antimatter be the perfect energy source for pretty much any Civilization, By the way, I have no way to Check this, How much Clout does Nicoli Kardashev have in the scientific community? Things like that are hard to check into.

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That's not to mention though. My idea of how to construct a Dyson sphere would be more like a swarming orbit of solar cells, producing and releasing more into orbit until no light could escape, It could take thousands of years to do this, And we would need more material than the earth has, So I can understand how it would be an impossibility for us. But, maybe not for every culture.

Though the material and engineering problems would be would be difficult, I work around the principle that nothing is impossible. It's kind of like Thomas Edison, He tried hundreds of filaments for the light bulb before he found tungsten, He was asked about this once by a reporter, He told them, He never got discouraged because, in those failed attempts, He found hundreds of ways not to make a light bulb. I'm optimistic to a fault, But I do realize it is a fault though lol. In short, What seems impossible for us today, May not be in maybe a thousand years

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Ahh, That link got me to reading up on Freeman Dyson, I like that guy. He's not the most credible in his field. At least currently, he likes to go against the grain. people tend to view him as a Doc Brown kind of guy, "Kinda out there" but I still like the man

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19. Thomas R. MorrisonDowning petulant pilots with logic since 2018

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Yeah antimatter is the most efficient energy source, but it seems that antimatter is hard to come by. I heard an interesting idea once about violating the law of baryon conservation, which could change the equation dramatically, but so far it seems like antimatter is quite sparse and of course making it costs a mad magnitude of energy, so...

Honestly all I know about Kardashev is his scale of civilizations - which is a cool idea, if a bit facile. I mean, all he was trying to do is find a way to categorize civilizations by using obvious "yardsticks" of energy control. So I put him in a category akin to Frank Drake: they came up with fun ideas, but not particularly challenging ideas.

Oh if we're ever capable of building a Dyson sphere, it'll take much longer to get to that point than a millennium. And like I said, by the time we can do it, we won't need to.

Edison was more tenacious than bright, frankly. The guy can't hold a candle to Tesla - that's who really spawned the modern era.

Dyson was awesome - people with big ideas are wonderful. Sometimes those ideas change the world. Sometimes they're just fun to think about. Either way it's a win-win.

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