NASA/ESA Hubble Space Telescope Image: A cross-section of the Universe

This is an image of a galaxy cluster taken by the NASA/ESA Hubble Space Telescope gives a remarkable cross-section of the Universe, showing objects at different distances and stages in cosmic history.

They range from cosmic near neighbours to objects seen in the early years of the Universe. 

The 14-hour exposure shows objects around a billion times fainter than can be seen with the naked eye. 

Credit: NASA, ESA

An image of a galaxy cluster taken by the NASA/ESA Hubble Space Telescope gives a remarkable cross-section of the Universe, showing objects at different distances and stages in cosmic history.

They range from cosmic near neighbours to objects seen in the early years of the Universe. The 14-hour exposure shows objects around a billion times fainter than can be seen with the naked eye.

This new Hubble image showcases a remarkable variety of objects at different distances from us, extending back over halfway to the edge of the observable Universe.

The galaxies in this image mostly lie within about five billion light-years of us, but the field also contains objects that are both closer and more distant.

Studies of this region of the sky have shown that many of the objects that appear to lie close together may actually be billions of light-years apart.

This is because several groups of galaxies lie along our line of sight, creating something of an optical illusion.

Hubble's cross-section of the Universe is completed by distorted images of galaxies in the very distant background.

These objects are sometimes distorted due to a process called gravitational lensing, an extremely valuable technique in astronomy for studying very distant objects.

This lensing is caused by the bending of the space-time continuum by massive galaxies lying close to our line of sight to distant objects.

One of the lens systems visible here is called CLASS B1608+656, which appears as a small loop in the centre of the image. It features two foreground galaxies distorting and amplifying the light of a distant quasar.

The light from this bright disc of matter, which is currently falling into a black hole, has taken nine billion years to reach us—two thirds of the age of the Universe.

As well as CLASS B1608+656, astronomers have identified two other gravitational lenses within this image. Two galaxies, dubbed Fred and Ginger by the researchers who studied them, contain enough mass to visibly distort the light from objects behind them.

Fred, also known more prosaically as [FMK2006] ACS J160919+6532, lies near the lens galaxies in CLASS B1608+656, while Ginger ([FMK2006] ACS J160910+6532) is markedly closer to us.

Despite their different distances from us, both can be seen near to CLASS B1608+656 in the central region of this Hubble image.

Dark Matter: Cosmologists weigh cosmic filaments and voids

A zoomed-out view of galaxies identified by the Sloan Digital Sky Survey. 

Filaments and voids are visible at this scale.

Cosmologists have established that much of the stuff of the universe is made of dark matter, a mysterious, invisible substance that can't be directly detected but which exerts a gravitational pull on surrounding objects.

Dark matter is thought to exist in a vast network of filaments throughout the universe, pulling luminous galaxies into an interconnected web of clusters, interspersed with seemingly empty voids.

Researchers at the University of Pennsylvania have measured the "weight" of these cosmic voids and filaments for the first time, showing the former are not as empty as they look.

The studies of voids and filaments are currently available on the ArXiv (arXiv:1402.3302) and were conducted by graduate student Joseph Clampitt and professor Bhuvnesh Jain of the Department of Physics and Astronomy in Penn's School of Arts & Sciences.

Gravitational lensing, the tiny distortions of distant galaxy images due to intervening matter, allows scientists to weigh galaxies by measuring how much their light bends.

Voids, on the other hand, are enormous, seemingly empty spaces in the universe with scarcely any galaxies visible — an arrangement that makes measuring their contents through lensing more difficult.

While galaxies and filaments have more mass than the average regions of the universe, voids have less mass than average.

This unbalanced distribution causes matter to rapidly move away from voids and towards the concentrations of mass along the cosmic filaments that lie between them.

A depiction of filaments and voids from The Max Planck Institute for Astrophysics’ Millennium Simulation Project.

"This means that voids act like objects with an effectively negative mass," Clampitt said, "such that even light rays bend away from them. They act roughly like concave lenses, the opposite of big galaxies, which act like convex lenses."

Clampitt and Jain detected the tiny distortions produced by voids on the images of nearly 40 million galaxies in the Sloan Digital Sky Survey.

This breakthrough came just a few months after they, along with Masahiro Takada of Tokyo University's Institute for the Physics and Mathematics of the Universe, detected the lensing signal from the dark matter filaments that connect galaxies.

"The measurements came as a wonderful surprise," Jain said. "Theoretical studies had predicted that we'd have to wait for much bigger surveys well into the future to detect void lensing. Joseph's ingenious analysis techniques extracted a subtle signal no one had seen before."

Their results show that voids are not as empty as they appear. Dark matter and other dim structures permeate all the way to the center of the voids.

"Although the density of this matter is far less than average," Clampitt said, "it is somewhat surprising that the voids are not as empty as the galaxy distribution suggests."

"The density at the center of a typical void," Jain said, "is about half the mean density in the universe, but that still leaves the voids with an enormous deficit in mass, about a thousand trillion times the mass of the sun."

NASA Hubble Team Finds Monster 'El Gordo' Galaxy

NASA's Hubble Space Telescope has weighed the largest known galaxy cluster in the distant universe, catalogued as ACT-CL J0102-4915, and found it definitely lives up to its nickname -- El Gordo (Spanish for "the fat one").

By measuring how much the cluster's gravity warps images of galaxies in the distant background, a team of astronomers has calculated the cluster's mass to be as much as 3 million billion times the mass of our sun. 

Hubble data show the galaxy cluster, which is 9.7 billion light-years away from Earth, is roughly 43 percent more massive than earlier estimates.

The team used Hubble to measure how strongly the mass of the cluster warped space. 

Hubble's high resolution allowed measurements of so-called "weak lensing," where the cluster's immense gravity subtly distorts space like a funhouse mirror and warps images of background galaxies. 

The greater the warping, the more mass is locked up in the cluster.

Image Credit: NASA/ESA

Hubble Image: Magnifying the distant universe

Credit: ESA/Hubble & NASA, Acknowledgement: Nick Rose

Galaxy clusters are some of the most massive structures that can be found in the Universe, large groups of galaxies bound together by gravity.

This image from the NASA/ESA Hubble Space Telescope reveals one of these clusters, known as MACS J0454.1-0300.

Each of the bright spots seen here is a galaxy, and each is home to many millions, or even billions, of stars.

Astronomers have determined the mass of MACS J0454.1-0300 to be around 180 trillion times the mass of the sun.

Clusters like this are so massive that their gravity can even change the behavior of space around them, bending the path of light as it travels through them, sometimes amplifying it and acting like a cosmic magnifying glass.

Thanks to this effect, it is possible to see objects that are so far away from us that they would otherwise be too faint to be detected.

In this case, several objects appear to be dramatically elongated and are seen as sweeping arcs to the left of this image.

These are galaxies located at vast distances behind the cluster, their image has been amplified, but also distorted, as their light passes through MACS J0454.1-0300.

This process, known as gravitational lensing, is an extremely valuable tool for astronomers as they peer at very distant objects.

This effect will be put to good use with the start of Hubble's Frontier Fields program over the next few years, which aims to explore very distant objects located behind lensing clusters, similar to MACS J0454.1-0300, to investigate how stars and galaxies formed and evolved in the early Universe.

Chandra and XMM-Newton: Direct measurement of distant black hole's spin

Multiple images of a distant quasar known as RX J1131-1231 are visible in this combined view from Chandra (pink) and Hubble (red, green, and blue). 

Credit: NASA/CXC/Univ of Michigan/R.C.Reis et al; Optical: NASA/STSc

Astronomers have used NASA's Chandra X-ray Observatory and the European Space Agency's (ESA) XMM-Newton to show a supermassive black hole six billion light years from Earth is spinning extremely rapidly.

This first direct measurement of the spin of such a distant black hole is an important advance for understanding how black holes grow over time.

Chandra X-ray Observatory

Black holes are defined by just two simple characteristics: mass and spin.

While astronomers have long been able to measure black hole masses very effectively, determining their spins has been much more difficult.

In the past decade, astronomers have devised ways of estimating spins for black holes at distances greater than several billion light-years away, meaning we see the region around black holes as they were billions of years ago.

However, determining the spins of these remote black holes involves several steps that rely on one another.

Rubens Reis

"We want to be able to cut out the middle man, so to speak, of determining the spins of black holes across the universe," said Rubens Reis of the University of Michigan in Ann Arbor, who led a paper describing this result that was published online Wednesday in the journal Nature.

Reis and his colleagues determined the spin of the supermassive black hole that is pulling in surrounding gas, producing an extremely luminous quasar known as RX J1131-1231 (RX J1131 for short).

ESA XMM-Newton

Because of fortuitous alignment, the distortion of space-time by the gravitational field of a giant elliptical galaxy along the line of sight to the quasar acts as a gravitational lens that magnifies the light from the quasar.

Gravitational lensing, first predicted by Einstein, offers a rare opportunity to study the innermost region in distant quasars by acting as a natural telescope and magnifying the light from these sources.

Mark Reynolds

"Because of this gravitational lens, we were able to get very detailed information on the X-ray spectrum – that is, the amount of X-rays seen at different energies – from RX J1131," said co-author Mark Reynolds also of Michigan.

"This in turn allowed us to get a very accurate value for how fast the black hole is spinning."

The X-rays are produced when a swirling accretion disk of gas and dust that surrounds the black hole creates a multimillion-degree cloud, or corona near the black hole.

X-rays from this corona reflect off the inner edge of the accretion disk.

The strong gravitational forces near the black hole alter the reflected X-ray spectrum. The larger the change in the spectrum, the closer the inner edge of the disk must be to the black hole.

More information: Paper: dx.doi.org/10.1038/nature13031

ESA NASA Hubble Image: A space-time magnifying glass

Galaxy cluster Abell S1077, as seen by the NASA/ESA Hubble Space Telescope’s Wide Field Camera 3 and the Advanced Camera for Surveys. 

Credit: ESA/Hubble & NASA 

Bright arcs are smeared around the heart of galaxy cluster Abell S1077 in this image taken by the NASA/ESA Hubble space telescope.

The arcs are stretched images of distant galaxies distorted by the cluster's enormous gravitational field.

Galaxy clusters are large groupings of galaxies, each hosting millions of stars. They are the largest existing structures in the Universe, bound by the gravitational attraction between them.

The amount of matter condensed in such groupings is so high that their gravity is enough to warp even the fabric of space-time, distorting the path that light takes when it travels through the cluster.

In some cases, this phenomenon produces an effect somewhat like a magnifying lens, allowing us to see objects that are aligned behind the cluster and that would otherwise be undetectable from Earth.

In this image, stretched stripes that look like scratches on a lens are in fact galaxies whose light is heavily distorted by the gravitational field of the cluster.

Astronomers use the effects of gravitational lensing to peer far back in time and space to see the furthest objects located in the early Universe.

One of the record holders is galaxy MACS0647-JD, whose light was magnified by galaxy cluster MACS J0647+7015 and has been travelling for 13.3 billion years to reach Earth.