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tkdguy

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I managed to show Hubble to younger boy a couple weeks back.  Happened to check the sat tracker on my phone at just the right time.  We watched it sail past from our driveway.

 

I can never time the ISS flybys though.  I saw it once on a July 4th, incredibly bright, with a Space Shuttle trailing behind.  The fireworks that followed shortly thereafter paled in comparison.  I haven't seen the space station since.

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In this month's Scientific American:

 

* A feature article on "the emptiest place in the universe." Astronemers have found a "supervoid" -- a volume of space about 1.8 billion light-years waide that is incredibly deficient in galaxies or anything else. It lies in the direction of another cosmic anomaly, the large "cold spot" in the WMAP image of the cosmic background radiation. A supervoid should cause such a cold spot, but -- large though it is -- the supervoid still doesn't seem big enough to explain the WMAP cold spot through known physics. More observations are needed to nail down the supervoid's size more precisely. It is possible, though (if I understand the author correctly), that this might be the first clue to accelerated expansion and dark energy that doesn't depend on supernova measurements. Or possibly modified gravity or other new physics.

 

* Another feature article on the OSIRIS_REx mission to retrieve material from a carbonaceous chondrite asteroid. The target asteroid, Bennu, is particularly important because it's an Earth-grazer with an unstable orbit.

 

And in non-space news, the issue includes an article about the neurochemistry of making zombies. No, really. The zombies are cockroaches, and the perpetrator is a wasp, but still -- zombies.

 

Ah, Nature. You never cease to amaze and terrify me.

 

Dean Shomshak

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xkcd actually dealt with that argument. It is not really one:

realistic_criteria.png

https://xkcd.com/1232/

 

It is realy just an argument from people who have no good argument against space exploration, and try to bring out a dead-beat argument.

Once you realise it is a dead-beat argument, all you will hear is a surrender by the other party.

 

Global extinction by planetary event is still a likely possibility. And might be a core driving factor in conflicts.

People being actually raised with a example for "the pale blue dot" in thier nightsky might have tremedous social effect once they return home. Same way most other "studying abroad" has positive effect on leaders right now.

I asume colonising another planet would either accelerate "solving all problems" or even make it possible in the first palce.

 

Same way Urbino once helped fan the flames of Renaisance.

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The bizarre light curve of KIC 8462852 is even more bizarre than originally thought.

 

link but that's to the arXiv preprint server, so it's a technical journal paper in pre-referee form. Page 4 of that PDF has the long-term light curve, and while it doesn't look like Mickey Mouse or anything, there's nothing in the known Universe that does that.

 

Less informative but more readable bit here

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Here we go: what the Kepler mission was supposed to do.

 

A CATALOG OF KEPLER HABITABLE ZONE EXOPLANET CANDIDATES, submitted to Astrophysical Journal.

 

Twenty prime candidates: confirmed planets, all in the "conservative" (i.e., least optimistic habitable zone definition) HZ, planets with radii less than twice that of Earth. Another hundred candidates (some not yet confirmed) in the more optimistic HZ and accepting any planetary radius. This is out of somewhat more than 4000 total planets/planetary candidates found by Kepler.

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http://phys.org/news/2016-08-scientists-unveil-earth-like-planet.html

 

Proxima Centauri? Whoa. That's only 4.2 light years away. If it can be substantiated, that's really exciting. I wonder how fast a probe could travel there, using the best drawing-board propulsion tech we could come up with this century. At .042 c, it would take 100 years.

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http://phys.org/news/2016-08-scientists-unveil-earth-like-planet.html

 

Proxima Centauri? Whoa. That's only 4.2 light years away. If it can be substantiated, that's really exciting. I wonder how fast a probe could travel there, using the best drawing-board propulsion tech we could come up with this century. At .042 c, it would take 100 years.

Proxima is a bit wierder then Alpha and Beta.

It is that 3rd star that elipses around Centauri A+B. Wich technically makes Alpha Centrauri a tripple star system. Or two star systems walking together?

Also since it orbit brings it closer and farther from the earth, it and Alpha Centauri Proper switch who is "closest to the sun" every other milennia.

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I can just see the protests this is going to cause. From the somewhat reasonable "We have no idea what the long-term effects are going to be" to the "I'm Jeb here and I'ma telling you that the gubmint is using these plasmoid x-rays ta mind control people. Thanks for takin' ma call George."

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http://phys.org/news/2016-08-scientists-unveil-earth-like-planet.htmlProxima Centauri? Whoa. That's only 4.2 light years away. If it can be substantiated, that's really exciting. I wonder how fast a probe could travel there, using the best drawing-board propulsion tech we could come up with this century. At .042 c, it would take 100 years.

Trying to scratch out how to detect such a planet. It'd have to be, really roughly, 0.04 AUs away from a star of Proxima's luminosity (0.0017 Lsun). It'd be in roughly a 28-day orbit, and the stellar velocity induced by that planet would be roughly 5 cm/s. Nope, not gonna see that. Astrometric orbit is even less detectable, and direct imaging seems even more like NFW regime.

 

That kind of forces you to an eclipse if you are gonna see it. Assuming same size planet as Earth, that means planet disk is 0.004 of the stellar disk area. Yeah, that's easy, probably easy enough to do from the ground.

 

But eclipses are really unlikely. Insanely unlikely.

 

Well, let's see what's in the official statement. Tomorrow, you say?

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No, it'll be tidally locked to Proxima, almost certainly. With a distance from Proxima to the G-K dwarf pair of at least 5500 AU's, the planet is about 1/7 of a million times closer to Proxima than the others. Now, it is possible (since that orbit isn't known) that Proxima's orbit will carry it quite close to the alpha Cen pair's barycenter, but it's very unlikely to have any effect on a locked condition around Proxima.

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No, it'll be tidally locked to Proxima, almost certainly. With a distance from Proxima to the G-K dwarf pair of at least 5500 AU's, the planet is about 1/7 of a million times closer to Proxima than the others. Now, it is possible (since that orbit isn't known) that Proxima's orbit will carry it quite close to the alpha Cen pair's barycenter, but it's very unlikely to have any effect on a locked condition around Proxima.

 

How stable would this planet's orbit be? (Yes, I did just finish The Three-Body Problem.)

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