Largest Lens Ever Discovered

K Tanmay writes "A team of Astronomers have found a natural lens capable of resolving details as fine as 10 microarcseconds across - equivalent to seeing a sugar cube on the Moon, from Earth. The lens comprises of a cloud of interstellar gas, and works on the principle of scintillation; where the clumpiness inside a cloud of gas creates a density change thus bending and focusing the light. This technique, dubbed 'Earth-Orbit Synthesis', will be first used to study black holes in distant quasars, so don't expect spectacular wallpaper replacing images. There's also an interview with Dr. Hayley Bignall, an astronomer from the Joint Institute for Very Long Baseline Interferometry in Europe (JIVE), where she discusses the concept of using interstellar scintillation to get observations that we could never measure from here on earth." Update: 02/22 18:23 GMT by T : That wikipedia link had led to the wrong place; here's the definition for arcsecond if you still want to read it.

Comments

Re:Actually...

[DigitaLunatiC]

A starlike object that may send out radio waves and other forms of energy; large red shifts imply enormous recession velocities [dictionary.com]

Hope that's satisfactory.

Re:Actually...

[Anonymous Coward]

Quasi-Stellar Radio Source, IIRC. it doesn't explain a lot, though :)

Re: Actually...

[Black Parrot]

> What is a quasar?

Here's the Wikipedia article on quasars.

> I've never really had a satisfactory explanation for this.

Sorry; satisfaction isn't guaranteed.

IANAA

[3ryon]

I am not an astrophysist, but does the phrase, "will be first used to study black holes in distant quasars" have any meaning at all?

Re:IANAA

[Abcd1234]

Umm... yes. Supermassive blackholes are the leading candidates for the engines driving quasars. From Google:

"Quasar - an enormously bright object at the edge of our Universe that emits massive amounts of energy. In an optical telescope, they appear point-like, similar to stars, from which they derive their name. Their high luminosity is created from matter falling into a supermassive black hole in the centers of distant galaxies."

Re:IANAA

[merlin_jim]

I am not an astrophysist, but does the phrase, "will be first used to study black holes in distant quasars" have any meaning at all?

I was just about to post the same thing.

AFAIK, a quasar is a far-universe object with a particular radio signature which indicates that it is highly energetic. The best theories state that this is a result of a large graviational mass (which probably previously went through a fusing-of-hydrogen-into-helium star stage) collapsing to the point that the gravitational gradient causes the nuclei in the atoms to seperate from their electron orbitals, all the protons and electrons neutralizing, and thus is a large ball of very hot very energetic neutrons.

A black hole is what happens when not even the energy involved at that stage is enough to prevent the matter from collapsing further, to the point where light itself cannot enter, and the mathematical equations governing the workings of the universe completely break down.

It is possible for a black hole to be small enough to fit inside a quasar. The usual result is that all matter touching the black hole is sucked inside, quickly, and you eventually have a bigger black hole.

A black hole can exist on a quantum level; that is, on a scale such that it could only have been formed by quantum forces in the early universe, and that it has a very small event horizon. However, the neutron-star-gobbling behaviour detailed above is asymptotic. There is a point where such a black hole would not eat its parent star immediately; that is where the black hole is so small and its gravitational gradient so steep that it gains practically no mass, gobbling up mere atoms on each orbit (black holes this small can orbit inside of solid matter)... however if its just a little bit larger than that, there's an exponential growth factor of the rate of consumption, governed by orbital mechanics, size of the black hole, and structural integrity of the matter matrix in which it is embedded.

To put it another way, the black hole eating matter slows its orbit, which causes more matter infall as it passes through, because a neutron star (and every other substance we know of) is incredibly fluid under the gravitational forces at work. This causes the black hole to increase in size quickly, causing still more matter to infall.

The point? The only black holes inside quasars are smaller than nuclei. And if we can only see a sugar cube on the moon, there's no way we're seeing nuclei 10 billion light years away, so there's no fucking way this can be used to look at black holes inside quasars.

The story may have been referring to a search for quasars that are infalling to black holes near them (a distance of 0.5 light year or less would cause something like this to happen), or perhaps to two seperate categories of objects that this new effect could be used to investigate...

Very Large Array

[FTL]

Check out the telescope array they used to find this lens. I don't know what's more impressive, the sheer size or the fact that each of the dishes are mobile and shift up and down the tracks so that the array can reconfigure itself for different types of observations.

I remember seeing a photo of this array as a child. Back then it only had five dishes. I had no idea that it had been filled out. Why don't we hear about this sort of thing?

Re:Very Large Array

[Chordonblue]

Hmmm.. You get to see some GREAT views of it in action in 'Contact'! :)

Re:Very Large Array

[RobertFisher]

Actually, the VLA has pretty much been in its current configuration for almost 25 years : see this historical note for some of its amazing history. The reason why you probably saw only five dishes is that the array can be operated in different modes. Depending on whether an astronomer wants a highly zoomed-in, extremely high-resolution image, or a wider field of view with lower resolution, he can instruct the telescope operators to move the array dishes either closer or father (respectively) on their tracks. Its one of the most basic tricks of radio interferometry. Sometimes even a single dish is used to repeat an observation of a highly resolved region at the same frequency; although the single dish cannot match the resolution of the array, it _can_ detect the total power emitted, and therefore determine how much the high-resolution observation "missed".

You're absolutely right that we don't hear as much about radio astronomonical observations. There are probably a few reasons. The first stems from the fact that astronomers tend to specialize in a given waveband -- the knowledge and expertise that is required to observe in the optical is very different from that required to observe in the radio, and both are in turn radically different from that required to observe in gamma rays. A few exceptionally talented astronomers operate in a couple of bands, but almost none operate across the entire spectrum. Radio astronomers are a minority within the astronomical community, and while they do really great science, it is primarily on sources filled with cold gas or electrons gyrating in the magnetic field, and are somewhat more difficult to popularize than a snazzy Hubble photo. The other reason, I think, is largely cultural and political. NASA does a great job pushing its science (Hubble, Chandra, Spitzer, planetary missions) to the public's attention, and devotes a lot of its effort culling the media's attention. The remainder of the astronomical community, including the national radio and optical observatories, tends to be much more conservative, and does not make much of an effort to garner attention. Generally you will only hear of their work when the press appears at one of the American Astronomical Soceity (AAS) and snatches up a few of their stories to splash up in their papers and broadcasts.

This parent posting was really great, and I applaud the moderators who modded it up. However, sadly, it was the ONLY reasonable post modded at 5 -- the rest are just a bunch of idiots making stupid comments which some other idiot found funny. Posters and moderators should definitely try harder to keep postings on topic and technically worthy. That is, after all, what slashdot is all about.

Bob

Re:Black Holes in Distant Quasars

[beeplet]

Part of the problem with the idea that the red shift is a doppler effect is that the observed quasars are apparently all in a relatively spherical arrangement about the Earth, thus implying that the Earth must be the center of the observed universe

Nonsense. The observed quasars appear isotropic for the same reason the cosmic microwave background is isotropic: we are looking back at a fairly homogeneous early universe. It is more reasonable to infer that quasars appear roughly equidistant because they were common during some point in the evolution of the universe; it is the separation in time, not distance, that matters.

Re:Better name??

[Ralph Wiggam]

Sherley finally stopped fighting with Rerun last year when he died.

I think JIVE is a great name.

-B

Not the "Largest Lens Ever Discovered"

[barakn]

Entire galaxy clusters perform gravitational lensing. Galaxy clusters, in terms of mass and size, are vastly larger than these gas clouds, which are either a million kilometers away or wide, depending on how you interpret this poorly worded sentence:

The length of a telescope needed to peer into the mouth of the blazar would have to be gigantic, about a million kilometers wide.

Re:Let's Crush Wikipedia

[Anonymous Coward]

Wikipedia is fine at the moment.

Last time there were server problems, a few of the servers had exploded, one of the servers arrived pre-exploded, and the rest had been ordered but were still in the mail.

The funding problem could theoretically have been solved earlier, using a time machine, however that was not accomplished due to technical difficulties.

Wikipedia is an encyclopaedia, not a dictionary. The dictionary is called Wiktionary.

(Approximate quote from Wikipedia developer: Average response time is ~200ms, slashdotting barely registered.)

uhm...

[Hegestratos]

There's also an interview with Dr. Hayley Bignall, [...], where he discusses [...].

He? I know astrophysicist is a male-dominated profession. But a name like 'Hayley' should at the very least make one wonder. See this page to accurately determine Dr. Bignall's gender.

Furthermore, this is nothing really new; see this /. story, amongst others.

Still, it's a very creative way of increasing resolution! Not to mention difficult and time-consuming. I wonder how believable the results are. I use a similar technique (called Speckle Masking) to eliminate earth-atmosphere scintillation from Solar observations, with astounding results. These, however, can be checked against single 'lucky shot' images of extrodinary quality or observations from space...

Cheers,

Alfred

Re:Actually...

[Scott Ransom]

Actually, that is not satisfactory... Your definition was valid in the 60's and 70's but not today.

Now we know that they are distant galaxies that have active nuclei. The nuclei are powered by supermassive (10^6-10^8 solar masses) black holes. What we are seeing is the point-like emission from near these black holes (i.e. the jets and/or an accretion disk). The radiation is often visible in radio, optical, and X-ray bands.

PS: IAAA (I am an astronomer)

Re:Shit-for-Brains

[Anonymous Coward]

comprises = consists of
Your choice #1 uses "comprised" where you mean "composed."

so the choices are:
The lens comprises
or
The lens consists of
or
The lens is composed of

Re:Black Holes in Distant Quasars

[Anonymous Coward]

They appear roughly equidistant from the Earth, it is thought, because they were all in existence at roughly the same time. Remember that distance (on the intergalactic scale) equates to age, so that objects which lie a certain distance away appear to us as they actually were during a particular common epoch, not as they are now.