Hubble Finds Double Einstein Ring

[Jay-qu]

NASA's Hubble Space Telescope has revealed a never-before-seen optical alignment in space: a pair of glowing rings, one nestled inside the other like a bull's-eye pattern. The double-ring pattern is caused by the complex bending of light from two distant galaxies strung directly behind a foreground massive galaxy, like three beads on a string.

 

lefthttp://hypography.com/gallery/files/1/1/0/1/web_print_395270_thumb.jpg[/img]More than just a novelty, this very rare phenomenon can offer insight into dark matter, dark energy, the nature of distant galaxies, and even the curvature of the universe.

 

The ring was found by an international team of astronomers led by Raphael Gavazzi and Tommaso Treu of the University of California, Santa Barbara. The discovery is part of the ongoing Sloan Lens Advanced Camera for Surveys (SLACS) program. The team is reporting its results at the 211th meeting of the American Astronomical Society in Austin, Texas. A paper has been submitted to The Astrophysical Journal.

 

The phenomenon, called gravitational lensing, occurs when a massive galaxy in the foreground bends the light rays from a distant galaxy behind it, in much the same way as a magnifying glass would. When both galaxies are exactly lined up, the light forms a circle, called an "Einstein ring," around the foreground galaxy. If another background galaxy lies precisely on the same sightline, a second, larger ring will appear.

 

Because the odds of seeing such a special alignment are estimated to be 1 in 10,000, Tommaso says that they "hit the jackpot." The odds of seeing this phenomenon are less than winning two consecutive bets on a single number at Roulette.

 

"Such stunning cosmic coincidences reveal so much about nature. Dark matter is not hidden to lensing," added Leonidas Moustakas of the Jet Propulsion Laboratory in Pasadena, Calif. "The elegance of this lens is trumped only by the secrets of nature that it reveals."

 

The massive foreground galaxy is almost perfectly aligned in the sky with two background galaxies at different distances. The foreground galaxy is 3 billion light-years away. The inner ring and outer ring are comprised of multiple images of two galaxies at a distance of 6 billion and approximately 11 billion light-years.

 

SLACS team member Adam Bolton of the University of Hawaii's Institute for Astronomy in Honolulu first identified the lens in the Sloan Digital Sky Survey (SDSS). "The original signature that led us to this discovery was a mere 500 photons (particles of light) hidden among 500,000 other photons in the SDSS spectrum of the foreground galaxy," commented Bolton.

 

"The twin rings were clearly visible in the Hubble image, added Tommaso. "When I first saw it I said 'wow, this is insane!' I could not believe it!"

 

The distribution of dark matter in the foreground galaxies that is warping space to create the gravitational lens can be precisely mapped. Tommaso finds that the fall-off in density of the dark matter is similar to what is seen in spiral galaxies (as measured by the speed of a galaxy's rotation, which yields a value for the amount of dark matter pulling on it), though he emphasizes there is no physical reason to explain this relationship.

 

In addition, the geometry of the two Einstein rings allowed the team to measure the mass of the middle galaxy precisely to be a value of 1 billion solar masses. The team reports that this is the first measurement of the mass of a dwarf galaxy at cosmological distance (redshift of z=0.6).

 

A sample of several dozen double rings such as this one would offer a purely independent measure. The comparative radius of the rings could also be used to provide an independent measure of the curvature of space by gravity. This would help in determining the matter content of the universe and the properties of dark energy.

 

Observations of the cosmic microwave background (a relic from the Big Bang) favor flat geometry. A sample of 50 suitable double Einstein rings would be sufficient to measure the dark matter content of the universe and the equation of state of the dark energy (a measure of its pressure) to 10 percent precision. Other double Einstein rings could be found with wide-field space telescope sky surveys that are being proposed for the Joint Dark Energy Mission (JDEM) and recently recommended by the National Research Council.

 

Credit: NASA, ESA, R. Gavazzi and T. Treu (University of California, Santa Barbara)

[Earth Prince]

the universal shape so far as our cosmos is concerned is the sphere. why should all forms that we see in the universe have the shape of a sphere. I think the sphere is the creation of gravitational forces which seek the center of the sphere. In the center of the sphere is the black hole, the center of gravity in the sphere under consideration.

 

A question I want to ask the forum is that if there is a law of gravity pushing everything into a common center, then shouldn't there be a counterbalancing force, the law of levitation? If there was only gravity, then everything will collapse into a common center. What force makes water vapour to rise?

 

Ladies and gentlemen, it is time man begun to tap the force of levitation, the counterpart to the force of gravity. thank you

[Tormod]

the universal shape so far as our cosmos is concerned is the sphere. why should all forms that we see in the universe have the shape of a sphere.

 

What evidence do you offer that everything is sphere-shaped?

[freeztar]

A question I want to ask the forum is that if there is a law of gravity pushing everything into a common center, then shouldn't there be a counterbalancing force, the law of levitation?

 

There are lots of counterbalancing forces such as centrifugal force (which is not really a true force).

 

If there was only gravity, then everything will collapse into a common center.

 

Fortunately for us then, there's more than just gravity.

 

What force makes water vapour to rise?

Again, there's hardly ever only a single force at work. Look up evaporation.

[Earth Prince]

Thanks for your useful comments about gravity. - about the sphere - most if not all planets and their satellites have spherical shapes. motion may give some objects like galaxies spiral shapes with many arms but when you take a map of the galaxy you will see that it is a flattened sphere in rapid motion. put some water in your palms and sprinkle it in the air and you will see spheres of water rise out of your hand before falling on the ground. Can we call the sphere the default shape? The reason for this spherical shape is that gravity in any body seeks a common center - or should I say drives mass to a common center. As someone said, there are many other forces in motion like levitation which drives substance away from the common center and the various other counterbalancing forces - like cyclical motion.

[freeztar]

Levitation is not a force, it is a process.

Levitation - Wikipedia, the free encyclopedia

[Pyrotex]

...most if not all planets and their satellites have spherical shapes. ...you will see spheres of water ...Can we call the sphere the default shape? The reason for this spherical shape....

Just as there are many problems for which the answer is "2" {like, what is 12 divided by 6}, there are many problems for which the answer is a sphere.

 

There really is no such thing as a "default" shape in the Universe, if you mean a shape that is taken if no other forces or processes are at work. Random swirls and filaments can be seen everywhere just as often as spheres. Consider the shape of a tree.

 

No, things take shapes for good reasons. Their history of forces and experiences determine their shape.

 

If gravity is the dominant force over a collection of matter, then most forces on that matter will tend to be in the direction of their common Center of Mass (which can be calculated). This will always tend to make the collection more spherical, not less spherical.

 

As for beads of water, it is a different force: Surface Tension. At the border between water and air, the water molecules pull on each other like rubber bands. The force is not "to the center" but along the surface. However, this has the affect of trying to MINIMIZE the surface area of the blob. What is the shape with the minimum surface area for a given volume? A sphere.

 

Spheres also come about out of random motion. Consider spherical galaxies. No one star is in a "spherical orbit". Most of them are in highly elliptical or chaotic orbits. Yet, ON AVERAGE, the placement of stars appears to be a sphere. It's just what you would expect, from statistics.

 

The spherical shape is associated with attractive forces, surface tension, random distributions, minimum area, equilibrium, circular motion and symmetry. That's a LOT of good, solid reasons.

 

But there is nothing "magic" or "default" about the sphere.

[Tormod]

I think the basic mistake is assuming that the universe is spherical simply because large-scale objects tend to appear spherical. At the really huge scales they don't, however. Look at superclusters, for example...just endless walls of galaxies and space.

 

The *observable* universe appears spherical, which can be easily explained, while we have absolutely no proof as to the shape of the entire universe (if we can claim that the phrase "entire universe" has a meaning at all...). :doh: