What type of telescope is chandra

They found a lack of bright stars near the center of the remnant. This implied that a star like the Sun did not donate material to the white dwarf until it reached critical mass. A merger between two white dwarfs is favored instead.

The paper is also available online. The paper is available online. This is significant because it may help answer some questions about our Sun's earliest days as well as some about the Solar System today.

Figure This artist's illustration depicts the object where astronomers discovered the X-ray flare. HOPS is called a young "protostar" because it is in the earliest phase of stellar evolution that occurs right after a large cloud of gas and dust has started to collapse.

Grosso et al. The flare is shown as a continuous loop in the inset box of the illustration. The rapid increase and slow decrease in the amount of X-rays is similar to the behavior of X-ray flares from young stars more evolved than HOPS No X-rays were detected from the protostar outside this flaring period, implying that during these times HOPS was at least ten times fainter, on average, than the flare at its maximum.

It is also 2, times more powerful than the brightest X-ray flare observed from the Sun, a middle-aged star of relatively low mass. This "outflow" removes angular momentum from the system, allowing material to fall from the disk onto the growing young protostar.

Astronomers have seen such an outflow from HOPS and think powerful X-ray flares like the one observed by Chandra could strip electrons from atoms at the base of it. This may be important for driving the outflow by magnetic forces. Assuming something similar happened in our Sun, the nuclear reactions caused by this collision could explain unusual abundances of elements in certain types of meteorites found on Earth.

Astronomers will need longer X-ray observations to determine how frequent such flares are during this very early phase of development for stars like our Sun. Figure The illustration shows HOPS surrounded by a donut-shaped cocoon of material dark brown — containing about half of the protostar's mass — that is falling in towards the central star.

Much of the light from the infant star in HOPS is unable to pierce through this cocoon, but X-rays from the flare blue are powerful enough to do so. Infrared light emitted by HOPS is scattered off the inside of the cocoon white and yellow.

The visualization has been loaded into a VR environment as a novel method of exploring these simulations, and is available for free at both the Steam and Viveport VR stores.

Each color represents different phenomena including Wolf-Rayet stars white , their orbits grey , and hot gas due to the supersonic wind collisions observed by Chandra blue and cyan. There are also regions where cooler material red and yellow overlaps with the hot gas purple.

Russell et al. Wolf-Rayet stars produce so much light that they blow off their outer layers into space to create supersonic winds. Watch as some of this material is captured by the black hole's gravity and plummets toward it. The center of the galaxy is too distant for Chandra to detect individual examples of these collisions, but the overall X-ray glow of this hot gas is detectable with Chandra's sharp X-ray vision. The white twinkling crosses are the Wolf-Rayet stars, and their orbits are in grey which can be toggled on and off.

The blue and cyan colors show the simulation's X-ray emission from hot gas due to the supersonic wind collisions observed by Chandra, while the red and yellow show all of the wind material, which is dominated by cooler gas and seen infrared and other telescopes. The purple is where the red and blue overlap. Each element of the simulation is loaded into the VR environment, creating a data-based simulation. By providing a six-degrees-of-freedom VR experience, the user can look and move in any direction they choose.

The user can also play the simulation at different speeds and choose between seeing all 25 winds or just one wind to observe how the individual elements affect each other in this environment. Espinasse et al. The black hole's strong gravity pulls material away from the companion star into an X-ray emitting disk surrounding the black hole.

These jets are pointed in opposite directions, launched from outside the event horizon along magnetic field lines. The inset shows a movie that cycles through the four Chandra observations, where "day 0" corresponds to the first observation on November 13th, , about four months after the jet's launch. The southern jet is too faint to be detected in the May and June observations. This means the object travels almost as quickly towards us as the light it generates, giving the illusion that the jet's motion is more rapid than the speed of light.

This included evidence that the jets are decelerating as they travel away from the black hole. These interactions might be the cause of the jets' deceleration. When the jets collide with surrounding material in interstellar space, shock waves — akin to the sonic booms caused by supersonic aircraft — occur. This process generates particle energies that are higher than that of the Large Hadron Collider.

This amount of mass is comparable to what could be accumulated on the disk around the black hole in the space of a few hours, and is equivalent to about a thousand Halley's Comets or about million times the mass of the Empire State Building.

Figure Astronomers may have discovered a new kind of survival story: a star that had a brush with a giant black hole and lived to tell the tale through exclamations of X-rays. Miniutti et al. The black hole, located in a galaxy called GSN , has a mass about , times that of the Sun, putting it on the small end of the scale for supermassive black holes. The stellar detritus enters into a disk surrounding the black hole and releases a burst of X-rays that Chandra and XMM-Newton can detect. In addition, King predicts gravitational waves will be emitted by the black hole and white dwarf pair, especially at their nearest point.

In this case, the rate of mass loss steadily slows down, and the white dwarf slowly spirals away from the black hole. This would be a remarkably slow and convoluted way for the universe to make a planet! First, it can take a more massive, surviving star too long to complete an orbit around a black hole for astronomers to see repeated bursts. Another issue is that supermassive black holes that are much more massive than the one in GSN may directly swallow a star rather than the star falling into orbits where they periodically lose mass.

Such encounters could be one of the main ways for black holes the size of the one in GSN to grow. If the white dwarf was the core of the red giant that was completely stripped of its hydrogen, then it should be rich in helium. The helium would have been created by the fusion of hydrogen atoms during the evolution of the red giant. This record-breaking, gargantuan eruption came from a black hole in a distant galaxy cluster hundreds of millions of light years away.

Helens in ripped off the top of the mountain," said Simona Giacintucci of the Naval Research Laboratory in Washington, DC, and lead author of the study. Galaxy clusters are the largest structures in the Universe held together by gravity, containing thousands of individual galaxies, dark matter, and hot gas.

This happens when matter falling toward the black hole is redirected into jets, or beams, that blast outward into space and slam into any surrounding material. Norbert Werner and colleagues reported the discovery of an unusual curved edge in the Chandra image of the cluster. They considered whether this represented part of the wall of a cavity in the hot gas created by jets from the supermassive black hole.

However, they discounted this possibility, in part because a huge amount of energy would have been required for the black hole to create a cavity this large. First, they showed that the curved edge is also detected by XMM-Newton, thus confirming the Chandra observation. Their crucial advance was the use of new radio data from the MWA and data from the GMRT archives to show the curved edge is indeed part of the wall of a cavity, because it borders a region filled with radio emission.

This emission is from electrons accelerated to nearly the speed of light. The acceleration likely originated from the supermassive black hole.

This shutdown can be explained by the Chandra data, which show that the densest and coolest gas seen in X-rays is currently located at a different position from the central galaxy. If this gas shifted away from the galaxy it will have deprived the black hole of fuel for its growth, turning off the jets.

Giacintucci, et al. Evidence for the biggest explosion seen in the Universe is contained in these composite images. The hot gas that pervades clusters like Ophiuchus gives off much of its light as X-rays. In the inset, Chandra's X-ray data are pink.

In the center of the Ophiuchus cluster is a large galaxy containing a supermassive black hole. Researchers have traced the source of this gigantic eruption to jets that blasted away from the black hole and carved out a large cavity in the hot gas. A labeled version includes a dashed line showing the edge of the cavity in the hot gas seen in X-rays from both Chandra and XMM-Newton.

Radio emission from electrons accelerated to almost the speed of light fills this cavity, providing evidence that an eruption of unprecedented size took place. Table 2: Some descriptive text to Figure This black hole has a mass of about 6. They have studied the jet in radio, optical, and X-ray light, including with Chandra.

And now by using Chandra observations, researchers have seen that sections of the jet are moving at nearly the speed of light. Some material from the inner part of the accretion disk falls onto the black hole and some of it is redirected away from the black hole in the form of narrow beams, or jets, of material along magnetic field lines.

Because this infall process is irregular, the jets are made of clumps or knots that can sometimes be identified with Chandra and other telescopes.

The X-ray data show motion with apparent speeds of 6. For example, the moving features could be a wave or a shock, similar to a sonic boom from a supersonic plane, rather than tracing the motions of matter. The team observed that the feature moving with an apparent speed of 6.

For this to occur the team must be seeing X-rays from the same particles at both times, and not a moving wave. The size of the ring around the black hole seen with the Event Horizon Telescope is about a hundred million times smaller than the size of the jet seen with Chandra.

The Chandra observations investigate ejected material within the jet that was launched from the black hole hundreds and thousands of years earlier. Figure This new multiwavelength image of the Crab Nebula combines X-ray light from the Chandra X-ray Observatory in blue with visible light from the Hubble Space Telescope in yellow and infrared light seen by the Spitzer Space Telescope in red.

This particular combination of light from across the electromagnetic spectrum highlights the nested structure of the pulsar wind nebula. The X-rays reveal the beating heart of the Crab, the neutron-star remnant from the supernova explosion seen almost a thousand years ago.

This neutron star is the super-dense collapsed core of an exploded star and is now a pulsar that rotates at a blistering rate of 30 times per second.

A disk of X-ray-emitting material, spewing jets of high-energy particles perpendicular to the disk, surrounds the pulsar. The infrared light in this image shows synchrotron radiation, formed from streams of charged particles spiraling around the pulsar's strong magnetic fields.

The visible light is emission from oxygen that has been heated by higher-energy ultraviolet and X-ray synchrotron radiation. The delicate tendrils seen in visible light form what astronomers call a "cage" around the rich tapestry of synchrotron radiation, which in turn encompasses the energetic fury of the X-ray disk and jets.

These multiwavelength interconnected structures illustrate that the pulsar is the main energy source for the emission seen by all three telescopes. The powerhouse "engine" energizing the entire system is a pulsar, a rapidly spinning neutron star, the super-dense crushed core of the exploded star.

The tiny dynamo is blasting out blistering pulses of radiation 30 times a second with unbelievable clockwork precision.

The movie is available to planetariums and other centers of informal learning worldwide. The interplay of the multiwavelength observations illuminate all of these structures. Without combining X-ray, infrared and visible light, you don't get the full picture. Figure This visualization features a three-dimensional multiwavelength representation of the Crab Nebula, a pulsar wind nebula that is the remains of an exploded star.

Summers, J. Olmsted, L. Hustak, J. DePasquale, G. This view zooms in to present the Hubble, Spitzer and Chandra images of the Crab Nebula, each highlighting one of the nested structures in the system. The video then begins a slow buildup of the three-dimensional X-ray structure, showing the pulsar and a ringed disk of energized material, and adding jets of particles firing off from opposite sides of the energetic dynamo.

This distinctive form of radiation occurs when streams of charged particles spiral around magnetic field lines. There is also infrared emission from dust and gas. Looking like a cage around the entire system, this shell of glowing gas consists of tentacle-shaped filaments of ionized oxygen oxygen missing one or more electrons. The tsunami of particles unleashed by the pulsar is pushing on this expanding debris cloud like an animal rattling its cage.

They reveal that the nebula is not a classic supernova remnant as once commonly thought. Instead, the system is better classified as a pulsar wind nebula. A traditional supernova remnant consists of a blast wave, and debris from the supernova that has been heated to millions of degrees.

In a pulsar wind nebula, the system's inner region consists of lower-temperature gas that is heated up to thousands of degrees by the high-energy synchrotron radiation.

You can understand the energy from the pulsar at the core moving out to the synchrotron cloud, and then further out to the filaments of the cage. Their initial step was reviewing past research on the Crab Nebula, an intensely studied object that formed from a supernova seen in by Chinese astronomers. The three-dimensional interpretation is guided by scientific data, knowledge and intuition, with artistic features filling out the structures. The effort combines a direct connection to the science and scientists of NASA's Astrophysics missions with attention to audience needs to enable youth, families and lifelong learners to explore fundamental questions in science, experience how science is done, and discover the universe for themselves.

It helps audiences understand how and why astronomers use multiple regions of the electromagnetic spectrum to explore and learn about our universe. Eventually all four clusters — each with a mass of at least several hundred trillion times that of the Sun — will merge to form one of the most massive objects in the universe.

Clusters consist of hundreds or even thousands of galaxies embedded in hot gas, and contain an even larger amount of invisible dark matter. Sometimes two galaxy clusters collide, as in the case of the Bullet Cluster , and occasionally more than two will collide at the same time. It contains two pairs of colliding galaxy clusters that are heading toward one another. The Chandra data revealed for the first time a shock wave — similar to the sonic boom from a supersonic aircraft — in hot gas visible with Chandra in the northern pair's collision.

Because this process depends on how far a merger has progressed, Abell offers a valuable case study, since the northern and the southern pairs of clusters are at different stages of merging. By contrast, in the northern pair, where the collision and merger has progressed further, the location of the heavy elements has been strongly influenced by the collision.

The highest abundances are found between the two cluster centers and to the left side of the cluster pair, while the lowest abundances are in the center of the cluster on the left side of the image. Data from the 6. Figure Each pair in the system contains two galaxy clusters that are well on their way to merging.

In the northern top pair seen in the composite image, the centers of each cluster have already passed by each other once, about to million years ago, and will eventually swing back around.

Schellenberger et al. When the star ran out of fuel, it collapsed onto itself and blew up as a supernova, possibly briefly becoming one of the brightest objects in the sky.

Although astronomers think that this happened around the year , there are no verifiable historical records to confirm this. Shortly after Chandra was launched aboard the Space Shuttle Columbia on July 23, , astronomers directed the observatory to point toward Cas A. Near the center of the intricate pattern of the expanding debris from the shattered star, the image revealed, for the first time, a dense object called a neutron star that the supernova left behind.

A new video shows the evolution of Cas A over time, enabling viewers to watch as incredibly hot gas — about 20 million degrees Fahrenheit — in the remnant expands outward. Hubble data from a single time period are shown to emphasize the changes in the Chandra data. Sato et al. Figure This video shows Chandra observations from to , or about the time it takes for a child to enter kindergarten and then graduate from high school. This gives astronomers a rare chance to watch as a cosmic object changes on human timescales, giving them new insight into the physics involved.

For example, particles in the blue outer shock wave carry more energy than those produced by the most powerful particle accelerators on Earth. As this blast wave hits material in its path it slows down, sending a shock wave backwards at speeds of millions of miles per hour video credit: Chandra X-ray Observatory, Published on 26 August The blast wave is composed of shock waves, similar to the sonic booms generated by a supersonic aircraft.

These expanding shock waves produce X-ray emission and are sites where particles are being accelerated to energies that reach about two times higher than the most powerful accelerator on Earth, the LHC Large Hadron Collider. These unusual reverse shocks are likely caused by the blast wave encountering clumps of material surrounding the remnant, as Sato and team discuss in their study.

This causes the blast wave to slow down more quickly, which re-energizes the reverse shock, making it brighter and faster. Particles are also accelerated to colossal energies by these inward moving shocks, reaching about 30 times the energies of the LHC.

In addition to finding the central neutron star , Chandra data have revealed the distribution of elements essential for life ejected by the explosion, have constructed a remarkable three dimensional model of the supernova remnant, and much more. These were combined with images taken by the Hubble Space Telescope between and This long-term look at Cas A allowed astronomers Dan Patnaude of CfA and Robert Fesen of Dartmouth College to learn more about the physics of the explosion and the resulting remnant from both the X-ray and optical data.

In addition to finding the central neutron star, Chandra data have revealed the distribution of elements essential for life ejected by the explosion, clues about the details of how the star exploded, and much more.

Chandra itself offered a significant leap in capability when it launched in It can observe X-ray sources — exploded stars, clusters of galaxies, and matter around black holes — times fainter than those observed by previous X-ray telescopes.

Figure Goddard scientist Will Zhang holds mirror segments made of silicon. The panel also deemed two other technologies — full-shell mirrors and adjustable optics — as being able to fulfill the requirements of the conceptual Lynx Observatory. This means future observatories could carry far more mirrors, creating a larger collection area for snagging X-rays emanating from high-energy phenomena in the universe.

Figure X-ray observatories like Chandra give us a new view of our universe beyond what we can see with our eyes. Goddard astrophysicist Dr. These include a couple X-ray observatories now being investigated as potential astrophysics Probe-class missions and another now being considered by the Japanese.

It has witnessed powerful eruptions from supermassive black holes. Astronomers have also used Chandra to map how the elements essential to life are spread from supernova explosions. For example, astronomers now use Chandra to study the effects of dark energy, test the impact of stellar radiation on exoplanets, and observe the outcomes of gravitational wave events.

It took decades of collaboration — between scientists and engineers, private companies and government agencies, and more — to make Chandra a reality. Northrup Grumman was and continues to be a prime contractor for Chandra, employing many staff members at the OCC. Draper decided to expand and not renew the OCC lease due to their own company growth. The new OCC brings all of the operational teams into one space to facilitate collaboration and situational awareness, but uses glass walls and physical separation to manage sound so individual team members can still effectively perform focused technical work.

They also created a purpose-built area for our spacecraft simulator, which was an important upgrade that will serve the mission well going forward. The Smithsonian Astrophysical Observatory in Cambridge, Massachusetts, controls Chandra's science and flight operations.

The corona is the outer atmosphere of a star. The results confirm that CMEs are produced in magnetically active stars and are relevant to stellar physics, and they also open the opportunity to systematically study such dramatic events in stars other than the Sun. Moreover, there is also expected to be an additional motion, always directed upwards, due to the CME associated with the flare".

The HETGS High-Energy Transmission Grating Spectrometer aboard Chandra is the only instrument that allows measurements of the motions of coronal plasmas with speeds of just a few tens of thousands of miles per hour. This is in excellent agreement with the expected behavior for the material linked to the stellar flare. Figure A giant stellar eruption detected for the first time. This artist's illustration depicts a CME from a star. The observed speed of the CME, however, is significantly lower than expected.

This suggests that the magnetic field in the active stars is probably less efficient in accelerating CMEs than the solar magnetic field. This event likely signaled the merger of two neutron stars and could give astronomers fresh insight into how neutron stars — dense stellar objects packed mainly with neutrons — are built.

If the jet is pointed along the line of sight to the Earth, a flash, or burst, of gamma rays can be detected. If the jet is not pointed in our direction, a different signal is needed to identify the merger. Figure These images show the location of an event, discovered by NASA's Chandra X-ray Observatory, that likely signals the merger of two neutron stars. Now, with the observation of a bright flare of X-rays, astronomers have found another signal, and discovered that two neutron stars likely merged to form a new, heavier and fast-spinning neutron star with an extraordinarily strong magnetic field.

The source is located in the Chandra Deep Field-South, the deepest X-ray image ever taken that contains almost 12 weeks of Chandra observing time, taken at various intervals over several years. The source appeared on March 22nd, and was discovered later in analysis of archival data. The X-rays showed a characteristic signature that matched those predicted for a newly-formed magnetar — a neutron star spinning around hundreds of times per second and possessing a tremendously strong magnetic field about a quadrillion times that of Earth's.

The amount of X-ray emission stayed roughly constant in X-ray brightness for about 30 minutes, then decreased in brightness by more than a factor of over 6. This showed that the neutron star merger produced a new, larger neutron star and not a black hole. That source, known as GW, produced a burst of gamma rays and an afterglow in light detected by many other telescopes, including Chandra.

Xue's team think that XT2 would also have been a source of gravitational waves, however it occurred before Advanced LIGO started its first observing run, and it was too distant to have been detected in any case. The source is in the outskirts of its host galaxy, which aligns with the idea that supernova explosions that left behind the neutron stars kicked them out of the center a few billion years earlier.

The galaxy itself also has certain properties — including a low rate of star formation compared to other galaxies of a similar mass — that are much more consistent with the type of galaxy where the merger of two neutron stars is expected to occur.

Massive stars are young and are associated with high rates of star formation. However, both estimates are highly uncertain because they depend on the detection of just one object each, so more examples are needed. Check out a new immersive, ultra-high-definition visualization. In this new visualization, the blue and cyan colors represent X-ray emission from hot gas, with temperatures of tens of millions of degrees; red shows ultraviolet emission from moderately dense regions of cooler gas, with temperatures of tens of thousands of degrees; and yellow shows of the cooler gas with the highest densities.

Sometimes clumps of gas will collide with gas ejected by other stars, resulting in a flash of X-rays when the gas is heated up, and then it quickly cools down. Farther away from the viewer, the movie also shows collisions of fast stellar winds producing X-rays.

These collisions are thought to provide the dominant source of hot gas that is seen by Chandra. When the outburst dies down the winds return to normal and the X-rays fade. The video can also be viewed on smartphones using the YouTube app.

Moving the phone around reveals a different portion of the movie, mimicking the effect in the VR goggles. Finally, most browsers on a computer also allow degree videos to be shown on YouTube. To look around, either click and drag the video, or click the direction pad in the corner. This one isn't as calming as the ones on Earth.

In a galaxy hosting a structure nicknamed the "Teacup," a galactic storm is raging. As matter in the central regions of the galaxy is pulled toward the black hole, it is energized by the strong gravity and magnetic fields near the black hole. The infalling material produces more radiation than all the stars in the host galaxy.

This kind of actively growing black hole is known as a quasar. Since then, professional astronomers using space-based telescopes have gathered clues about the history of this galaxy with an eye toward forecasting how stormy it will be in the future. This handle-shaped feature, which is located about 30, light-years from the supermassive black hole, was likely formed by one or more eruptions powered by the black hole.

Radio emission — shown in a separate composite image with the optical data — also outlines this bubble, and a bubble about the same size on the other side of the black hole. The amount of radiation required to ionize the atoms was compared with that inferred from optical observations of the quasar.

This comparison suggested that the quasar's radiation production had diminished by a factor of somewhere between 50 and over the last 40, to , years.

This inferred sharp decline led researchers to conclude that the quasar in the Teacup was fading or dying. The X-ray spectra that is, the amount of X-rays over a range of energies show that the quasar is heavily obscured by gas. This implies that the quasar is producing much more ionizing radiation than indicated by the estimates based on the optical data alone, and that rumors of the quasar's death may have been exaggerated.

Instead the quasar has dimmed by only a factor of 25 or less over the past , years. Such a wind, which was driven by radiation from the quasar, may have created the bubbles found in the Teacup. The Smithsonian's Astrophysical Observatory in Cambridge, MA, hosts the Chandra X-ray Center which operates the satellite, processes the data, and distributes it to scientists around the world for analysis.

The Center maintains an extensive public web site about the science results and an education program. Chandra carries four very sensitive mirrors nested inside each other. The energetic X-rays strike the insides of the hollow shells and are focussed onto electronic detectors at the end of the 9. Depending on which detector is used, very detailed images or spectra of the cosmic source can be made and analyzed. Chandra has imaged the spectacular, glowing remains of exploded stars, and taken spectra showing the dispersal of elements.

Chandra has observed the region around the supermassive black hole in the center of our Milky Way, and found black holes across the Universe. Chandra has traced the separation of dark matter from normal matter in the collision of galaxies in a cluster and is contributing to both dark matter and dark energy studies.

Electromagnetic radiation comes in a range of energies, known as the electromagnetic spectrum. The spectrum consists of radiation such as gamma rays, x-rays, ultraviolet, visible, infrared and radio. Electromagnetic radiation travels in waves, just like waves in an ocean. The energy of the radiation depends on the distance between the crests the highest points of the waves, or the wavelength. In general the smaller the wavelength, the higher the energy of the radiation. For historical reasons having to do with measuring distances to nearby stars, professional astronomers use the unit of parsecs, with one parsec being equal to 3.

A blackhole is a dense, compact object whose gravitational pull is so strong that - within a certain distance of it - nothing can escape, not even light. If a star has three times or more the mass of the Sun and collapses, it can form a black hole. These bizarre objects are found across the Universe -- within double star systems and at the centers of galaxies where giant black holes grow. X-ray telescopes like Chandra can see superheated matter that is swirling toward the event horizon of a black hole.

Chandra has revealed how black holes impact their environments, how they behave, and their role in helping shape the evolution of the cosmos. A supernova is the explosive death of a star, caused by the sudden onset of nuclear burning in a white dwarf star, or gravitational collapse of the core of massive star followed by a shock wave that disrupts the star.

Supernovas are some of the most dramatic events in the cosmos. These titanic events send shock waves rumbling through space and create giant bubbles of gas that have been superheated to millions of degrees. Chandra has captured supernovas and the remnants they've left behind in spectacular X-ray images, helping to determine the energy, composition, and dynamics of these celestial explosions.

Dark matter is a term used to describe matter that can be inferred to exist from its gravitational effects, but does not emit or absorb detectable amounts of light. The nature of dark matter is unknown. A substantial body of evidence indicates that it cannot be baryonic matter, i. The favored model is that dark matter is mostly composed of exotic particles formed when the universe was a fraction of a second old.

Such particles, which would require an extension of the so-called Standard Model of elementary particle physics, could be WIMPs weakly interacting massive particles , or axions, or sterile neutrinos. Dark energy is a hypothetical form of energy that permeates all space and exerts a negative pressure that causes the universe to expand at an ever-increasing rate. At the close of the 20th century, our perception of the Universe was jolted.

Instead of slowing down after the Big Bang, the expansion of the Universe was found to be accelerating. Was the cosmic acceleration due to Einstein's cosmological constant, a mysterious form of "dark energy," or perhaps a lack of understanding of gravity? The answer is still out there. By studying clusters of galaxies, X-ray astronomy is tackling this question using powerful techniques that are independent of other methods currently being employed or proposed for the future.

About Chandra Where is Chandra? Chandra NASA's Chandra X-ray Observatory is a telescope specially designed to detect X-ray emission from very hot regions of the Universe such as exploded stars, clusters The Sun and its planetary system formed Solar System One Star, eight planets, and a myriad of moons, comets, and asteroids.

Later, scientists announced a possible new kind of black hole in the galaxy M From eight months of observations, the scientists said the black hole could represent an evolutionary stage between small black holes formed from stars, and the much more massive ones lurking in the centers of galaxies.

Astronomers are on a continual hunt for "dark" matter , which is believed to be practically invisible stuff that makes most of the universe. So far, we can only detect it through its gravity. In , a team of astronomers spent more than hours using Chandra to watch the galaxy cluster 1E, which contains gas from a galaxy cluster collision.

Chandra's observations were combined with that of several other observatories. Researchers examined the effect the galaxy cluster had on gravitational lensing, which is a known way that gravity distorts the light from background galaxies.

Their observations of the gravity showed that normal matter and dark matter ripped apart during the galaxy collision. While the dark matter search continues, Chandra has been used to find other missing matter. In , researchers used Chandra and the European Space Agency's XMM-Newton observatory, probing a reservoir of gas resting along a wall of galaxies about million light-years away from Earth.

Scientists found evidence of baryons, which are electrons, protons and other particles that compose matter found through much of our universe. The researchers suspected the gas would contain a significant amount of this matter. While scientists continue to probe the nature of matter, Chandra continues to produce stunning pictures that also reveal the structure of the universe. These pictures include a survey of planetary nebulas and a fast-growing galaxy cluster , as well as a " superbubble " found in the Large Magellanic Cloud.

While G2 didn't produce the fireworks scientists hoped for, scientists did spot a megaflare that was times brighter than the black hole's normal quiescent state, three times brighter than the previous record holder.

The occasional reconfiguration of the field lines produces a bright x-ray outburst similar to magnetic flares seen on the sun. In , Chandra was one of several instruments that picked up a pulse of high-energy light from the powerful explosion caused by two merging neutron stars.

Observations with the National Science Foundation's Laser Interferometer Gravitational-wave Observatory LIGO had spotted gravitational waves tied to the collision, encouraging scientists to hunt for signs of the explosion's aftermath.