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The Astronomy Thread 
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Post The Astronomy Thread
Simulation describing the observed effects of a stellar remnant being ripped apart by a supermassive black hole.

Black Hole Caught Red-Handed in a Stellar Homicide


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Sun May 27, 2012 5:58 pm
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Post Re: The Astronomy Thread
You can hear the scream.


Sun May 27, 2012 6:26 pm
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Post Re: The Astronomy Thread
This is just tearing me apart..

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Sun May 27, 2012 7:23 pm
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Post Re: The Astronomy Thread
such a horrible choice of photo :p

We don't have a good enough telescope to see to THAT kind of resolution yet, although astronomers are pretty good at making educated guesses.

I'm just waiting for the projected 40 lens uberscope they want to put in the L point on the far side of the earth (to help shade from the sun), it should be able to resolve individual stars in distant galaxies <_<, although actually from what i hear getting them all into alignment will pose a difficulty, and thus give us really good shots of individual stars, but struggle with the whole rapid mapping of the galaxy with such high resolution.
with THEM we should be able to witness a realtime video of said stellar event.


Sun May 27, 2012 10:05 pm
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Post Re: The Astronomy Thread
Such an event must add lots of noise to certain radio frequencies. :o

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Mon May 28, 2012 4:41 am
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Post Re: The Astronomy Thread
Fotiadis_110 wrote:
I'm just waiting for the projected 40 lens uberscope they want to put in the L point on the far side of the earth (to help shade from the sun),
I don't think any of the Lagrangian points would provide much shade from the Sun. At best the Earth-Moon L2 would provide a brief period of shade while the moon is near full. The best(?) use of the Earth-Moon L2 would be to block radio transmissions from Earth.

That black hole video is fun, though!


Thu May 31, 2012 1:27 pm
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Post Re: The Astronomy Thread
In the Sun/Earth L2, Earth provides shade; if I recall correctly Herschel and other observatories are already in orbit around that point.

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Thu May 31, 2012 6:40 pm
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Post Re: The Astronomy Thread
I was gonna object against Riesstiu's last post, but apparently the umbra (full shadow) of the earth supposedly does reach almost exactly to (if not a bit beyond) the Sun-Eearth L2 :!:

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Fri Jun 01, 2012 7:47 am
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Post Re: The Astronomy Thread
Riess wrote:
In the Sun/Earth L2, Earth provides shade; if I recall correctly Herschel and other observatories are already in orbit around that point.
You're correct, Riess, and if Celestia is to be trusted, Earth would block most of the Sun's light at 1.5M km distance, … except for the fact that Herschel is in a Lissajous orbit around Sun/Earth L2 with an orbital radius of about 800'000 km which is about ½ of that radius, and would keep it out of Earth's shadow most of the time.


Fri Jun 01, 2012 4:29 pm
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Post Re: The Astronomy Thread
Timefly wrote:
Riess wrote:
In the Sun/Earth L2, Earth provides shade; if I recall correctly Herschel and other observatories are already in orbit around that point.
You're correct, Riess, and if Celestia is to be trusted, Earth would block most of the Sun's light at 1.5M km distance, … except for the fact that Herschel is in a Lissajous orbit around Sun/Earth L2 with an orbital radius of about 800'000 km which is about ½ of that radius, and would keep it out of Earth's shadow most of the time.


As long as the mirror isn't pointed within a certain angle to the sun, that doesn't matter. There's no light scattering in space. Besides, it has a "hood" to provide shade to the mirror if necessary.

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Sat Jun 02, 2012 2:10 am
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Post Re: The Astronomy Thread
fascinating, isn't there meant to be a super massive black hole at the centre f the galaxy?

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Sat Jun 02, 2012 3:07 am
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Post Re: The Astronomy Thread
I think it's a tad more than just "meant to be there" by now :P
It seems it'll be a while until ours gets to rip something apart tho, fortunately for us I would think.

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Sat Jun 02, 2012 7:50 am
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Post Re: The Astronomy Thread
A black hole eating a star. Astronomy turns astro-nom-nom-nom-y.


Mon Jun 04, 2012 12:40 am
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Post Re: The Astronomy Thread
GeoModder wrote:
Timefly wrote:
Riess wrote:
In the Sun/Earth L2, Earth provides shade; if I recall correctly Herschel and other observatories are already in orbit around that point.
You're correct, Riess, and if Celestia is to be trusted, Earth would block most of the Sun's light at 1.5M km distance, … except for the fact that Herschel is in a Lissajous orbit around Sun/Earth L2 with an orbital radius of about 800'000 km which is about ½ of that radius, and would keep it out of Earth's shadow most of the time.


As long as the mirror isn't pointed within a certain angle to the sun, that doesn't matter. There's no light scattering in space. Besides, it has a "hood" to provide shade to the mirror if necessary.


If your doing infrared work you can have solar heating induced noise regardless of the direction that the telescope is pointing.

Last time I read about a large interferometer telescope they wanted to put in orbit out beyond Jupiter's orbit to cut down on the noise generated by the solar irradiation. It was also supposed to be able to resolve continent sized objects at 10 light years.

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Mon Jun 04, 2012 8:38 pm
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Post Re: The Astronomy Thread
Yess, an astronomy thread!
I was on Gornergrat Observatory two weeks ago, as a culmination of my holidays between two projects (before i was sailing/"taxiing" and racing), and it was the first time i was really riding my astrography gear to the max. Results are quite unspectacular, but i learned a lot.
Maybe i´m going in July again (although Switzerland and especially Zermatt is horribly expensive), with better filters and stuff, and then i´m going trying the big ´uns,

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Wed Jun 06, 2012 6:42 am
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Post Re: The Astronomy Thread
Artfully done views of the recent Venus transit of the sun.


A nice closeup shot of Venus itself (from the Hinode spacecraft).
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Post Re: The Astronomy Thread
Gives you a really great idea of the scale of the solar system and just how big the sun really is when you see Venus so small next to it like that, even though it's much closer to us than the sun.


Thu Jun 07, 2012 5:17 am
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Post Re: The Astronomy Thread
ah, we missed that here in England, nice that it coincided with queens jubilee :)

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Thu Jun 07, 2012 7:38 am
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Post Re: The Astronomy Thread
Wintermute wrote:
Gives you a really great idea of the scale of the solar system and just how big the sun really is when you see Venus so small next to it like that, even though it's much closer to us than the sun.



Remind me of that "scale of the universe" flash video

http://scaleofuniverse.com/


Thu Jun 07, 2012 3:06 pm
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Post Alpha Centauri B b
The European Southern Observatory is reporting a detected planet (via radial velocity measurements) in very close orbit around Alpha Centauri B. The planet is only 1.1 Earth masses -- the smallest exoplanet yet detected -- but extremely close to the star (~6 million km radious, orbital period 3.236 days). Alpha Centauri B is slightly smaller and fainter than Sol, so the habitable zone would be right around Venus distance.

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I'm not sure exactly why the planet is designated "b" rather than "a", but those astronomers are a quirky lot.

Alpha Centauri is, of course, a binary system of two sunlike stars (A and B, spectral class G2V and K1V, respectively) 4.3 light years from Earth. It is the proposed location of many and varied inhabited planets throughout science fiction. Outsider proposes two: a Mars-sized planet in a roughly Mars-distance orbit around the A star, and a Venus-sized planet in an elongated orbit around the B star.

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http://www.eso.org/public/news/eso1241/
http://oklo.org/2012/10/16/alpha-centauri-b-b/
http://en.wikipedia.org/wiki/Alpha_Centauri

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Post Re: Alpha Centauri B b
Man, science is the best.

I've always wondered about binary systems. How close (or far) do the stars orbit from each other?

Also, how long before scientists start giving planets crazy sci-fi names instead of...well..."b"?

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Thu Oct 18, 2012 1:28 am
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Post Re: Alpha Centauri B b
I'd've thought they'd put a number on it rather than a letter - ie, if our sun is Sol, Mercury is Sol 1 or Sol I, Venus Sol 2 or Sol II, Terra Sol 3/Sol III, Mars Sol 4/Sol IV, etc. - so this would be Alpha Centauri B.I/Alpha Centauri B.1, with the letter indicating subsystem/star for multi-star systems.


Thu Oct 18, 2012 8:36 am
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Post Re: Alpha Centauri B b
hi hi

According to my sources at solstation.com:

Alpha Centauri A and B orbit with an average distance of about 23.7 AUs, swinging from 11.4 and 36 AUs distant in a highly elliptical orbit that lasts 79.9 years.

In a binary system, a planet must not be located too far away from its parent star, or its orbit will be unstable. If that distance exceeds about one fifth the closest approach of the other star, then the gravitational pull from the second star can disrupt the orbit of the planet.

Weigert and Holman in 1997 stated that recent (for the time) numerical integrations suggest that stable planetary orbits exist: within three AUs (four AUs for retrograde orbits) of either Alpha Centauri A or B in the plane of the binary's orbit; only as far as 0.23 AU for 90-degree inclined orbits; and beyond 70 AUs for planets circling both stars.

The presence of one close-orbiting planet usually indicates the presence of others, and many astronomers are now expected to devote more resources to detecting such potential planets around star B.

All in all, very exciting. :D


Thu Oct 18, 2012 9:00 am
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Post Re: Alpha Centauri B b
The AB periapsis of 11 AU is about Saturn distance, and the apoapsis of 36 AU is about Neptune/Pluto distance.

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It will be really interesting to see what kinds of planetary orbits such a system will have as more data shakes out over the coming years. In particular, I wonder whether the planets of A and B will be in the same plane (indicating that the two stars formed from the same disc), or whether they will be different indicating that the two stars formed from separate discs and subsequently captured each other. Though continuing discovery may be problematic for existing science fiction canon. :D

Regarding nomenclature: I believe planets are designated in the order in which they're found (rather than in the order from the primary), so it seems to me these designations are unlikely to stick in the long term if a complete planetary system is eventually identified. And of course, if we ever actually went there, they would be given more conventinal names. Though I suspect "Alpha Centauri" will always stick... it just sounds so nice.

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Post Re: Alpha Centauri B b
Count Casimir wrote:
Man, science is the best.

I've always wondered about binary systems. How close (or far) do the stars orbit from each other?

Also, how long before scientists start giving planets crazy sci-fi names instead of...well..."b"?


Woud you prefer P3X595?


Thu Oct 18, 2012 5:53 pm
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