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tkdguy

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So...are you guys more apprehensive or more excited at the possibility of encountering extraterrestrial life in possession of intelligence roughly equal to our level of cognitive maturity?

 

Excited. Even if the sped of light is absolute and there's no quick way of transiting the 1400 light years between us, it's still comforting to know we aren't alone.

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So...are you guys more apprehensive or more excited at the possibility of encountering extraterrestrial life in possession of intelligence roughly equal to our level of cognitive maturity?

If they are more advanced they could be a threat to us. Because if we are more advanced we will likely be a threat to them.

 

But maybe we surprise ourself or they surprise us.

Maybe contact with alien, intelligent won't be like all the contacts between natives and the "civilised" People we had in the past of our planet.

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So...are you guys more apprehensive or more excited at the possibility of encountering extraterrestrial life in possession of intelligence roughly equal to our level of cognitive maturity?

I haven't considered it much, because I think the probability of this happening in my lifetime is vanishingly small. And "in my lifetime" can be loosely translated as "in the next 20 years".
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Longer than that. Last I heard they thought it would take two generations of orbiting optical interferometer array instruments, and all work on those had the plug pulled back in 2005. Figure 25 years after the date on which they fund those things again.

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An important piece toward solving that problem, but not the only one. Some of the J-type carbon stars seem to be significant lithium producers too, which is not understood.

 

(At one point I had measured more lithium abundances than anyone else so I am personally acquainted with this issue.)

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If someone built a megastructure in space(dyson sphere/swarm etc, ringworld, topopolis, etc.), would we have the means to detect and distinguish it?

Being able to detect those was the entire idea of thinking them up in the first place.

 

The asumption was that a sufficiently advanced civilsiation could build them. And how they would "look" to us from outside.

All variants have a pretty unique infrared signature. Often acompanied by dimmed luminosity from the star they surround. We have not found any. But that might also be because they are "awesome but impractical".

If you could build a dyson sphere, you had no need to build one.

 

 

"A Dyson sphere is a hypothetical megastructure that completely encompasses a star and hence captures most or all of its power output. It was first described by Freeman Dyson. Dyson speculated that such structures would be the logical consequence of the long-term survival and escalating energy needs of a technological civilization, and proposed that searching for evidence of the existence of such structures might lead to the detection of advanced intelligent extraterrestrial life."

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How long until we can image exoplanets like Kepler 452b directly?

This month's Scientific American has an article about rival teams working to image exo-jovians directly. Specifically, they want to view very young jovians in IR. There are two theories about how jovians form: runaway accretion, or the direct collapse of a large portion of the protoplanetary disk of gas and dust, like star formation in miniature. The latter process would leave the new jovian much hotter than accretion would -- at least at first. After 100 million years or so, the jovian has cooled enough that it's impossible to tell how they formed.

 

Imaging super-Earths will be a bit more challenging, but the field is advancing so quickly that I'd expect smaller planets to be imaged within 10-15 years after imaging relatively near-to-star jovians. (And I know that a couple very remote exo-jovians have already been imaged directly.)

 

Dean Shomshak

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the big thing I want to know is

 

What happens to the inside of the sphere with the solar wind

 

If someone built a megastructure in space(dyson sphere/swarm etc, ringworld, topopolis, etc.), would we have the means to detect and distinguish it?

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the big thing I want to know is

 

What happens to the inside of the sphere with the solar wind

First of the whole idea of living on the inside of a dyson sphere is faulty. You won't get gravity there from the mass of the sphere. Something about how gravity behaves and negates itself on the inside of a sphere, it is complicated. But no gravity from inside a spehee towards the spehere. But you still got gravity from the sun.

If you need to generate gravity, you propably waste more energy then you get from the sphere. So living on the inside surfac of the sphere is out of question.

 

Secondly we have to differentiate between a dyson sphere (solid) and dyson shell (humongous solar sail, with inside habitats dangling from the shell on ropes).

In a solid sphere (you propably live on the outside) the shell needs to be able to withstand the wind. It would accumulate inside. It won't dent from the wind. You either have to let it out in regular intervalls (emergency vent) or have the gas fall back into the star.

In a shell the hope/idea is that the wind will hit all areas equally, resulting in stability. Wich propably won't work out.

 

In short anything but a dyson swarm/net or a niven ringworld is highly unlikely to be found.

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Also speaking of super-Earths, this month's Discover magazine has a pretty neat article about planetologists trying to figure out whether they could be habitable. The questions are complex, because their geology could be quite different from anything we see in the Solar System.

 

Example: A planet won't stay habitable for long if it lacks a magnetic field. The interior of a super-Earth could easily be hotter than Earth's interior -- but the greater pressure could still prevent iron from liquefying. So, no liquid iron core to make a magnetic field. Except... the greater heat *could* liquefy magnesium oxide despite the greater pressure, possibly resulting in a magnesium oxide layer that churns to make a magnetic field.

 

The upshot, the scientists interviewed for the article say, is that whatever we try to imagine for super-Earths, the reality will probably turn out to be weirder and more widely varied. Because that's how it's been for, like EVERYTHING astronomers have found for the last several decades.

 

Dean Shomshak

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