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Virtual Telescope Zooms In On Milky Way Black Hole
Posted by
samzenpus
on Thu Sep 04, 2008 02:04 AM
from the old-bob dept.
from the old-bob dept.
FiReaNGeL writes "An international team has obtained the closest views ever of what is believed to be a super-massive black hole at the center of the Milky Way galaxy. The astronomers used radio dishes in Hawaii, Arizona and California to create a virtual telescope more than 2,800 miles across that is capable of seeing details more than 1,000 times finer than the Hubble Space Telescope. The target of the observations was the source known as Sagittarius A* ("A-star"), long thought to mark the position of a black hole whose mass is 4 million times greater than the sun. Though Sagittarius A* was discovered 30 years ago, the new observations for the first time have an angular resolution, or ability to observe small details, that is matched to the size of the event horizon."
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obligatory (Score:5, Funny)
Thats your basic Beowulf cluster of telescopes.
Re:obligatory (Score:4, Funny)
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Re:obligatory (Score:5, Interesting)
Appropriate in this case, because one of the most loved science fiction tale about the galatic core is Larry Niven's Beowulf Schaeffer story "At the Core" (collected in Neutron Star [amazon.com] ). Niven, however, was writing before the idea of a supermassive black hole was current.
Nonetheless, remembering Niven's story fills me with some dread at his suggestion that the close proximity of stars at the core would set off a chain of supernovas, eventually flooding the galactic periphery with deadly radiation. Now this Slashdot post has really put a downer on my day.
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Re:obligatory (Score:4, Interesting)
>... Now this Slashdot post has really put a downer on my day.
Just follow the example of the Pierson Puppeteers and you'll be safe.
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On closer inspection (Score:5, Funny)
An international team has obtained the closest views ever of what is believed to be a super-massive black hole at the center of the Milky Way galaxy.
*Zoom Out*... "Is that?.. It.. it.. it's Oprah eating a klondike bar. Sorry folks, our mistake."
Note (Score:3, Informative)
The milky way is our galaxy.
Also, 2 different brands of chocolate bar.
Re: (Score:3, Funny)
How very insightful of you, now all you need to do is to break one milky way open and look for any bubbles in it, if you find one tilt the bar so the bubbles interior don't get any light and take a photograph, send your milky way black hole to nasa.
I can do science me!
freeresearcher.com (Score:4, Insightful)
"a virtual telescope more than 2,800 miles across that is capable of seeing details more than 1,000 times finer than the Hubble Space Telescope"
- ok, but HST is an optical telescope, not "radio dish".
Re: (Score:3, Informative)
They both have angular resolution. The radio telescope in question still has 1000 times the angular resolution of Hubble.
What, exactly, is your peeve here?
Re:freeresearcher.com (Score:5, Insightful)
"a virtual telescope more than 2,800 miles across that is capable of seeing details more than 1,000 times finer than the Hubble Space Telescope"
- ok, but HST is an optical telescope, not "radio dish".
It's all part of the same electromagnetic spectrum [wikipedia.org]. The fact that you can only see a very narrow bit of it doesn't change the fact that the rest can be used to look at things with the right tools. The only difference is wavelength. If you had the right "eyes" it would all be the same to you.
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Re:freeresearcher.com (Score:5, Funny)
But if we don't see these things in the visible light spectrum, how will we ever recognize them during sightseeing trips? If someone tells us to "take a left at the purple nebula", but the nebula is actually brown in visible light, then we're going to get really, really lost.
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Interferometry (Score:5, Informative)
Can we stop saying "virtual telescopes" and start using the proper grown up terms? Interferometry and Aperture Synthesis aren't hard to understand. It's a pet peeve of mine, and slashdotters should be of a level of intelligence that they can understand this stuff.
http://en.wikipedia.org/wiki/Astronomical_interferometer [wikipedia.org]
http://en.wikipedia.org/wiki/Aperture_synthesis [wikipedia.org]
Yes you get the same angular resolution as a much larger telescope (one as big as the distance between the telescopes), which is why you do it. However it's important to note that you you don't increase the amount of radiation you're collecting - it's still just the sum of the telescopes you're using.
I'll try to put it simply. Let's use optical telescopes as a familiar example. (In practice optical interferometry is much harder than radio astronomy, but I digress). The larger the diameter of the mirror (or lens) the more light we collect, and the smaller an object we can look at with reasonable detail (There is a physical relationship between the diameter of the telescope and the smallest thing you can resolve with it). We could space multiple telescopes a good distance apart and increase how small a piece of the sky we can look at in detail. The detail we could now resolve depends on the distance between the telescopes. However we're still only collecting as much light in total as the sum of the light collected by each scope. So even though we can look at a much smaller part of the sky, we won't be able to brighten up the image as much as if we had the larger telescope. It's still worth doing and it still yields discoveries, but it's not the same as having a massive telescope.
Re:Interferometry (Score:5, Funny)
We synthesize what we must because we can.
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Re:Interferometry (Score:5, Interesting)
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Re:Interferometry (Score:5, Interesting)
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Re: (Score:3, Funny)
Apologies, it was a straight copy and paste of the title. Luckily, I posted them in Chrome, so you may sue Google if you have suffered any permanent injuries as they hold all the rights :).
Re:Interferometry (Score:4, Interesting)
Just out of curiosity, how far could you push something like this? If you had an array of Hubble sized telescopes in space and could put them whatever distance you'd like from each other, what sort of results could you get?
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Re:Interferometry (Score:4, Interesting)
Veery good ones, but putting a telescope in the sky is 10-100 times the cost of one on the earth. That's why they are building ALMA, and they play with VLA, and SKA (square kilometer array).
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Re: (Score:3, Funny)
... and they play with VLA, and SKA (square kilometer array).
Cool! Can they play reggae or jazz to? ;-)
"Darwin" (Score:5, Interesting)
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Re:Interferometry (Score:4, Informative)
Good question
http://en.wikipedia.org/wiki/Space_Interferometry_Mission [wikipedia.org]
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Space Interferometry Mission (SIM) (Score:5, Informative)
If you had an array of Hubble sized telescopes in space and could put them whatever distance you'd like from each other, what sort of results could you get?
That is basically the Space Interferometry Mission (SIM) [nasa.gov], which alas has had funding troubles recently. The component telescopes are not the size of the Hubble, but the idea is exactly as you suggest. One thing you could do with this is detect Earth sized planets in a solar system like ours out to a reasonable distance.
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Re:Interferometry (Score:5, Informative)
Yes. Please.
And while we're at it, can article-writers stop referring to the submillimeter/microwave portion of the spectrum as "radio"?
Linking together radio dishes is not a big deal - radio astronomy goes back to the 1930s, and the Very Long Baseline Array has stretched from Hawaii to the Virgin Islands for decades now.
Linking together JCMT and SMA with some dishes on the mainland is a big deal in submillimeter astronomy. The Cosmic Microwave Background wasn't even discovered until the 1960s, and then it took another couple decades to develop serious observing capabilities. There's plenty of interferometry on Mauna Kea, both within the SMA and between the SMA and JCMT and/or CalTech Submillimeter Observatory, but that's all relatively short-baseline.
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Re:Interferometry (Score:4, Informative)
And while we're at it, can article-writers stop referring to the submillimeter/microwave portion of the spectrum as "radio"?
Just out of interest, why? It is part of the RF spectrum, just way way way up there. It's also good to call it that, because it reminds people that it's part of the same thing as light, xrays, Ham Radio, and mobile phones.
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Re:Interferometry (Score:4, Interesting)
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Re: (Score:3, Insightful)
The thing that plugs into your cable or DSL isn't really a 'modem' either but that doesn't stop people from calling it one. 'Virtual telescope' is far easier for laymen to grasp. Yes, slashdotters can for the most part understand this stuff, but your pedantry isn't really called for.
Re:Interferometry (Score:4, Informative)
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Re: (Score:3, Interesting)
Re:Interferometry (Score:5, Insightful)
Then...
"I'll try to put it simply..."
And with two wiki links included? Sheesh... now I know you stated that
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Obligatory (Score:4, Funny)
- I'll be here the whole week. Tip your waitress. Try the veal.
Pics? (Score:5, Funny)
Re:Pics? (Score:5, Funny)
Pics or it didn't happen
I believe that the pictures look pretty similar to the screenshots of Doom 4.
Parent
Help Wanted? (Score:3, Insightful)
Pics or it didn't happen
Oh, we have lots of pretty pictures (of colorful surrounding gas). We just don't have enough picture details to determine what it is, that is happening.
What we could really use, like out of a science fiction story, is to stumble upon an ancient astronomer's time-lapse photo project. About 10-20 million years should be sufficient. But in case our stumbling plan fails, how would like to go down in history, sayyyy in 10-20 million years from now, as the guy who got the ball rolling?
Re:Pics? (Score:5, Funny)
Here is one high resolution picture of the blackhole
.
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First pics released! (Score:5, Funny)
Paths (Score:5, Funny)
Sagittarius A* ? :)
Dijkstra's Scorpio is better
Ok ok, I'm not a space nerd!
Muse (Score:5, Funny)
The Biggest....? (Score:4, Funny)
Hmm..... Near the "A-Star"?
Does this mean that in the center of our galaxy is the biggest "A-Hole" in our galaxy?
Re: (Score:3, Funny)
Re:so... (Score:5, Funny)
> what does the giant black hole spin around?
Windows Vista
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Re: (Score:3, Insightful)
The only thing in the Universe that is more dense and unexplained
The intelligence and Ego of George W Bush
Re:so... (Score:5, Funny)
An exceptionally massive turtle.
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Re: (Score:3, Informative)
[ ]
Re:Pics! (Score:5, Funny)
with the gravitational pull it would look like:
><
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Re:also... (Score:5, Informative)
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expanding ... (Score:4, Insightful)
To determine that something is expanding you must first know its dimensions. Since we don't know the dimensions of the universe, we can't really tell if it is expanding or not. There is movement within the observed portion of the universe that is compatible with the concept of an expanding universe.
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Black hole gravity (Score:3, Interesting)
General relativity makes no predictions about what is happening at the center of black holes - there is a singularity in the equations there. Worse, in general relativity singularities are (probably) never "naked" - if you go in to see what is happening you can never come back out, or send a signal back out, to tell us about it.
But, yet, the gravity of the black hole, as experienced outside, does increase with time as things get sucked in.
Re: (Score:3, Interesting)
Also, the expansion takes the form of things moving away from each other, not themselves getting bigger. Black holes don't suck things in anymore than the Earth sucks in the moon. If you get close enough, yeah, you'll fall in. But it's not like water going down a drain, or a vacuum. There are black holes in the center of the galaxy that are frighteningly huge, millions of solar masses... that aren't gobbling up stars. While their gravity is strong, the distances involved quickly makes the pull very wea
Re: (Score:3, Informative)
There is an accretion disk around the event horizon, where things (dust, gas) are orbiting around at nearly the speed of light. As these things rub together, and as new stuff gets added, there is lots of energy to be detected far away - especially in jets of very hot matter out of the poles.
The event horizon itself, for a black hole of this size, is not detectable. (Very small black holes should glow with Hawking radiation.)
Re:Black hole... where? (Score:5, Informative)
Here [mit.edu], actually.
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