Posted on 03/20/2019 12:42:50 AM PDT by LibWhacker
This study, which has combined images from the Hubble Space Telescope with spectroscopic observations from the GTC, has confirmed the existence of a new example of a gravitational lens, a phenomenon predicted by Albert Einstein's theory of General Relativity. In this case, the observed effect is due to the alteration caused by a galaxy that acts like a magnifying glass amplifying and distorting, in four separate images in the form of a cross, the light of another galaxy located 20,000 million light years away.
One of the most striking conclusions of Albert Einstein's theory of general relativity is that the trajectory of light curves in the presence of matter. This effect can be observed in the case of light emitted by a distant galaxy, when its light passes close to another galaxy on its way to the observer. The phenomenon is known as gravitational lensing, because it is comparable to the deviation of light rays by the classic glass lenses. Similarly, gravitational lenses act like magnifying glasses that change the size, shape, and intensity of the image of the distant object.
Depending on the degree of alignment of the two sources, multiple images of the distant source can be observed, such as four separate images in the form of a cross (hence the name "Einstein's cross"), rings, or arcs. It is in general extremely difficult to spot a gravitational lens, because the separation between the images produced by the lens is usually very small, requiring high-resolution images to see them. It was precisely analyzing Hubble Space Telescope high-resolution images that it was possible to locate an asterism that looked like a new example of Einstein cross.
An exceptional discovery
However, spotting four points of light in the shape of a cross positioned around a galaxy does not assure us that it is a lens, so we must show that the 4 images belong to the same object. To do this spectroscopic observations are needed. For this reason, a team of Italian scientists led by Daniela Bettoni of the Padova Observatory and Riccardo Scarpa of the IAC, decided to observe spectroscopically with GTC the supposed lens. According to Scarpa, "the result could not have been better. The atmosphere was very clean and with minimum turbulence (seeing), which allowed us to clearly separate the emission of three of the four images. The spectrum immediately gave us the answer we were looking for, the same emission line due to ionized hydrogen appeared in all three spectra at the same wavelength. There could be no doubt that it was actually the same source of light".
A new Einstein cross had been discovered, named J2211-0350 according to its coordinates on the sky. The object acting as a lens turns out to be an elliptical galaxy located at a distance of approximately 7 billion light years (z = 0.556), while the source is at least 20 billion light years away (z = 3.03). "Normally the source is a quasar, it was with great surprise that we realized the source in this case was another galaxy, in fact a galaxy with very intense emission lines which indicates it is a young object still forming large amounts of stars", explain Bettoni. Quite an achievement for GTC, considering only another lens of this type was known.
New research tool
Thanks to these new observations, presented in The Astrophysical Journal, astronomers now have one more tool to investigate the Universe. Gravitational lenses are important because they allow the study of the Universe in a unique way. Because the light of the different images, initially the same light, follows different paths in the Universe, thus any spectral differences must be due to the material that is between us and the source. Moreover, if the source is variable, we can see a time delay (one image illuminates before the others), which provides valuable information about the shape of the Universe.
Of course, the mass of the lens responsible for bending the light can be accurately derived, providing an important independent method to weight galaxies. Finally, as with a normal glass lens, the gravitational lens concentrates toward us the light from the source, making it possible to see intrinsically unreachable objects. In this case it could be calculated that the source is 5 times brighter than it would be without the lens.
Aha, very cool! Was wondering how we could "see" something 20 billion light years away when it seems to me that the so-called Cosmic Dark Age* would prevent any light that far out from reaching us. So this must be the answer... right?... right?... I don't know. Just trying to grok.
*In Big Bang cosmology, shortly after the blazingly bright Big Bang itself, there came a time when the universe was utterly dark. This period, before the first stars were born, and is thought to have lasted several hundred million years in our 13.8-billion-year-old universe. Astronomers call it the Cosmic Dark Ages... Source
If these "Einstein Crosses” are what these orthodox cosmologists claim they are, then it is amazing that we are so conveniently sitting right at the exact focal length for them to make such well focused images on 90° axes. I think that if they were such lenses there would be hundreds more which produce fuzzy, out-of-focus "Einstein Crosses" or even "Einstein Rings" where the light fails to come into focus. We don’t see that. . . Nor do we see light bent around in a single image matching another we see in the other side. We should.
The universe is about 13.8 billion years old, so any light we see has to have been travelling for 13.8 billion years or less – we call this the ‘observable universe’.
However, the distance to the edge of the observable universe is about 46 billion light years because the universe is expanding all of the time.
Imagine that a photon of light is emitted from a point on the edge of our observable universe.
While that photon has been travelling through space, the universe has expanded. We have moved away from the point where the light was emitted, and it has moved away from us!
Though the light might have only travelled for 13.8 billion years, the distance from us to the point it came from is, at present, 46 billion light years!
So how big is our universe? Well we don’t really know, but it’s big. So big that even light hasn’t had time to cross it in nearly 14 billion years! And it’s still getting bigger all of the time.
Read more at: https://phys.org/news/2015-10-big-universe.html#jCp
Here’s are some examples of Einstein Rings...
https://www.skyandtelescope.com/astronomy-news/einstein-rings/
And you are right. The alignment, as well as the focus,
needs to be right for us to see it. If we were in another
galaxy, we likely wouldn’t have seen this one, yet other
alignments could present themselves.
On occasion.
Now, if we could happen upon TWO such galactic gravity
lenses, with the right separation between them, and in
alignment and focus with us, then we might get to
see Four identical little Einstein Rings around an
Einstein Cross.
And see very, very far away indeed.
That’s why I challenge this "Einstein Cross" as what we should be seeing is a ring, or a blur, but four separately displayed images on 90° axes? What "lens" mechanism creates that? They toss off a spiral galaxy as an explanation, then blithely add the object being 4x displayed is actually FIVE TIMES more brilliant than any of the images for it to be so imaged. Say what? What is this super bright object? Something is not right here. Ad hoc explanations when pulled from thin vacuums don’t work.
I get what you’re saying. The only thing I can think of that would make any sense is some kind of polarized light (only waving 2 directions), but what do we know of that does that? *shrug*
It’s a pretty picture. I’ll get excited when they stop blaming the universe on dark matter/energy.
Sun dogs
Yes. Not a perfect analog, but very close.
But, since the only tangible measurement is through “visible light”, the universe is expanding at the speed of light.
The term “lens” is an analogy. The actual behavior of light depends on the geometry of the space through which it passes. This is calculated using the field equations of General Relativity, which are exceptionally complex and difficult to solve, but the basic idea is reasonably simple.
Most of us probably had geometry at some point. Almost certainly, that geometry was Euclidean geometry. This is geometry resulting from certain “self-evident” assumptions called postulates. For centuries this was the only geometry. In the 19th century, though, mathematicians realized that other geometries are possible. They began to develop these non-Euclidean geometries, even though it was “evident” that Euclidean geometry describes the universe.
Well, as maybe you guessed, the true geometry of the universe is NOT Euclidean. We only think it is because we don’t often deal with large distances. An anology is that the geometry of the earth’s surface appears Euclidean at small scale but not at large scale. Since we know the earth is non-Euclidean because it’s curved. By analogy, we say that the universe is also curved. The field equations simply relate this curvature to something easier to measure — energy. Energy causes curvature. This includes matter as well (E=mc^2).
There’s another phenomenon caused by matter, gravity. Gravity is just the name we called curvature before we understood this. Gravity IS curvature. It is also why we get “lensing”. It is not the same phenomenon as a glass lens though, so results from such lenses don’t apply
Of all the lines perpendicular to an ellipse, only four of them intersect the center point of the ellipse.
Ping.
“This includes matter as well (E=mc^2).”
Chicken / egg ?
Which came first? Matter or Space ?
I don’t get it. Shouldn’t there be 6 points of light, like in the Star of David? Einstein was Jewish. Why would he invent something in the shape of a cross?
The concept is fun, a natural telescope. The second lens would help greatly in power but also we are probably seeing the image inverted and reversed right now because of focal length. The second lens would turn it right side up in to proper perspective. lol
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