A revised version of David Bowie's Space Oddity, recorded by Commander Chris Hadfield on board the International Space Station.
A corona mass ejection (CME), associated with a solar flare, blew out from just around the edge of the Sun today in a glorious roiling wave (May 1, 2013). The video, taken in extreme ultraviolet light by NASA's Solar Dynamics Observatory spacecraft, covers about 2.5 hours. SOHO's C2 and C3 coronagraphs shows a large, bright, circular cloud of particles heading out into space. STEREO spacecraft, from their different perspectives in space, observed the flare. CME's carry over a billion tons of particles at over a million miles per hour.
This image shows the HR 8799 planets with starlight optically suppressed and data processing conducted to remove residual starlight. The star is at the center of the blackened circle in the image. The four spots indicated with the letters b through e are the planets. This is a composite image using 30 wavelengths of light and was obtained over a period of 1.25 hours on June 14 and 15, 2012.
A team of researchers belonging to a group called Project 1640, which is partly funded by NASA's Jet Propulsion Laboratory, Pasadena, California, used the Palomar Observatory near San Diego to obtain detailed spectra of the four planets. The results are revealing new information about the atmospheres of the four giant, red planets.
This illustration is an artist's impression of the thin, rocky debris disc discovered around the two Hyades white dwarfs. Rocky asteroids are thought to have been perturbed by planets within the system and diverted inwards towards the star, where they broke up, circled into a debris ring, and were then dragged onto the star itself.
The maps in this animation show how the sky looks at gamma-ray energies above 100 million electron volts (MeV) with a view centered on the north galactic pole. The first frame shows the sky during a three-hour interval prior to GRB 130427A. The second frame shows a three-hour interval starting 2.5 hours before the burst, and ending 30 minutes into the event. The Fermi team chose this interval to demonstrate how bright the burst was relative to the rest of the gamma-ray sky. This burst was bright enough that Fermi autonomously left its normal surveying mode to give the LAT instrument a better view, so the three-hour exposure following the burst does not cover the whole sky in the usual way.
This artist's concept illustrates the frenzied activity at the core of our Milky Way galaxy. The galactic center hosts a supermassive black hole in the region known as Sagittarius A*, or Sgr A*, with a mass of about four million times that of our sun. The Herschel space observatory has made detailed observations of surprisingly hot gas that may be orbiting or falling toward the supermassive black hole.
A dense torus of gas and dust surrounds the galactic center and occupies the innermost 15 light-years of our galaxy. Enshrouded within the disk is a central cavity, with a radius of a few light-years, filled with warm dust and lower density gas.
Part of this gas is being heated by the strong ultraviolet radiation from massive stars that closely orbit the central black hole. Heating also likely results from strong shocks, generated in collisions between gas clouds, or in material flowing at high speeds.
ESA’s Vega VV02 rocket is ready for liftoff, 4 May, 2013 (GMT).
Vega VV02 is the first of the five flights scheduled in ESA’s Vega Research and Technology Accompaniment – VERTA – program, which aims to demonstrate the flexibility of the launch system. At a minimum rate of two launches per year, the program will allow the smooth introduction of Vega for commercial exploitation.
VV02 will loft Proba-V, the first of four ESA missions, into space. Proba-V carries a reduced version of the Vegetation instrument currently flying on the Spot satellites to provide a daily overview of global vegetation growth.
This first VERTA flight will also demonstrate Vega's capability to launch multiple payloads into two different orbits. Proba-V, the prime payload, will be released first. The remaining two payloads: Vietnam Natural Resources, Environment and Disaster Monitoring Satellite (VNREDSat-1) built by Astrium for the Vietnamese government and the Estonian cubesat (ESTCube-1) will be released later, into a different orbit.
When we look into the distant cosmos, the great majority of the objects we see are galaxies: immense gatherings of stars, planets, gas, dust, and dark matter, showing up in all kind of shapes. This Hubble picture registers several, but the galaxy cataloged as 2MASX J05210136-2521450 stands out at a glance due to its interesting shape.
This object is an ultra-luminous infrared galaxy which emits a tremendous amount of light at infrared wavelengths. Scientists connect this to intense star formation activity, triggered by a collision between two interacting galaxies.
The merging process has left its signs: 2MASX J05210136-2521450 presents a single, bright nucleus and a spectacular outer structure that consists of a one-sided extension of the inner arms, with a tidal tail heading in the opposite direction, formed from material ripped out from the merging galaxies by gravitational forces.
The image is a combination of exposures taken by Hubble’s Advanced Camera for Surveys, using near-infrared and visible light.
The Danish 1.54-meter telescope located at ESO’s La Silla Observatory in Chile has captured a striking image of NGC 6559, an object that showcases the anarchy that reigns when stars form inside an interstellar cloud. This region of sky includes glowing red clouds of mostly hydrogen gas, blue regions where starlight is being reflected from tiny particles of dust and also dark regions where the dust is thick and opaque.
This image covers many shallow irregular pits with raised rims, concentrated along ridges and other topographic features. How did these odd features form?
One idea is that they could be from sublimation of shallow lenses of nearly pure ice, but why do the pits have raised rims? They can't be impact craters with such fortuitous alignment and irregular margins. They aren't wind-blown deposits because there are many boulders, too big to be moved by the wind. There are younger wind-blown drifts on top of the pits, and there's no clear connection to volcanism.
Some speculate that there were ancient oceans over this region--could that somehow explain these features? Ancient glaciation is another possibility, perhaps depositing ice-rich debris next to topographic obstacles.Future images of this region may provide clues, but for now this is a mystery.
NGC 6240: A pair of colliding spiral galaxies about 330 million light years from Earth.
Scientists have used Chandra to make a detailed study of an enormous cloud of hot gas enveloping two large, colliding galaxies in the system known as NGC 6240. This unusually large reservoir of gas contains as much mass as 10 billion Suns, spans about 300,000 light years, radiates at a temperature of more than 7 million degrees, and glows in X-rays (purple). The Chandra data have been combined with optical data from the Hubble, which show long tidal tails from the merging galaxies, extending to the right and bottom of the image.
Scale: Image is 3 arcmin across (About 290,000 light years).
These delicate wisps of gas make up an object known as SNR B0519-69.0, or SNR 0519 for short. The thin, blood-red shells are actually the remnants from when an unstable progenitor star exploded violently as a supernova around 600 years ago. There are several types of supernova, but for SNR 0519 the star that exploded is known to have been a white dwarf star — a Sun-like star in the final stages of its life.
SNR 0519 is located over 150,000 light-years from Earth in the southern constellation of Dorado (The Dolphinfish), a constellation that also contains most of our neighboring galaxy the Large Magellanic Cloud (LMC). Because of this, this region of the sky is full of intriguing and beautiful deep sky objects.
The LMC orbits the Milky Way galaxy as a satellite and is the fourth largest in our group of galaxies, the Local Group. SNR 0519 is not alone in the LMC; the NASA/ESA Hubble Space Telescope also came across a similar bauble a few years ago in SNR B0509-67.5, a supernova of the same type as SNR 0519 with a strikingly similar appearance.
The spinning vortex of Saturn's north polar storm resembles a deep red rose of giant proportions surrounded by green foliage in this false-color image from NASA's Cassini spacecraft. Measurements have sized the eye at a staggering 1,250 miles (2,000 kilometers) across with cloud speeds as fast as 330 miles per hour (150 meters per second).
This image is among the first sunlit views of Saturn's north pole captured by Cassini's imaging cameras. When the spacecraft arrived in the Saturnian system in 2004, it was northern winter and the north pole was in darkness. Saturn's north pole was last imaged under sunlight by NASA's Voyager 2 in 1981; however, the observation geometry did not allow for detailed views of the poles. Consequently, it is not known how long this newly discovered north-polar hurricane has been active.
The images were taken with the Cassini spacecraft narrow-angle camera on November 27, 2012, using a combination of spectral filters sensitive to wavelengths of near-infrared light. The images filtered at 890 nanometers are projected as blue. The images filtered at 728 nanometers are projected as green, and images filtered at 752 nanometers are projected as red. In this scheme, red indicates low clouds and green indicates high ones.
The view was acquired at a distance of approximately 261,000 miles (419,000 kilometers) from Saturn and at a sun-Saturn-spacecraft, or phase, angle of 94 degrees. Image scale is 1 mile (2 kilometers) per pixel.
Andromeda, also known as M31, is the nearest major galaxy to our own Milky Way.
The Herschel observatory, a European space telescope for which NASA helped build instruments and process data, has stopped making observations after running out of liquid coolant as expected.
The European Space Agency mission, launched almost four years ago, revealed the universe's "coolest" secrets by observing the frigid side of planet, star and galaxy formation.
"Herschel gave us the opportunity to peer into the dark and cold regions of the universe that are invisible to other telescopes," said John Grunsfeld, associate administrator for NASA's Science Mission Directorate at NASA headquarters in Washington. "This successful mission demonstrates how NASA and ESA can work together to tackle unsolved mysteries in astronomy."
Confirmation the helium is exhausted came today, at the beginning of the spacecraft's daily communication session with its ground station in Western Australia. A clear rise in temperatures was measured in all of Herschel's instruments.
Herschel launched aboard an Ariane 5 rocket from French Guiana in May 2009. NASA's Jet Propulsion Laboratory in Pasadena, California, built components for two of Herschel's three science instruments. NASA also supports the U.S. astronomical community through the agency's Herschel Science Center, located at the California Institute of Technology's Infrared Processing and Analysis Center in Pasadena.
Herschel's detectors were designed to pick up the glow from celestial objects with infrared wavelengths as long as 625 micrometers, which is 1,000 times longer than what we can see with our eyes. Because heat interferes with these devices, they were chilled to temperatures as low as 2 kelvins (minus 271 degrees Celsius, or 456 Fahrenheit) using liquid helium. The detectors also were kept cold by the spacecraft's orbit, which is around a stable point called the second Lagrange point about 930,000 miles (1.5 million kilometers) from Earth. This location gave Herschel a better view of the universe.
"Herschel has improved our understanding of how new stars and planets form, but has also raised many new questions," said Paul Goldsmith, NASA Herschel project scientist at JPL. "Astronomers will be following up on Herschel's discoveries with ground-based and future space-based observatories for years to come."
The mission will not be making any more observations, but discoveries will continue. Astronomers still are looking over the data, much of which already is public and available through NASA's Herschel Science Center. The final batch of data will be public in about six months.
"Our goal is to help the U.S. community exploit the nuggets of gold that lie in that data archive," said Phil Appleton, project scientist at the science center.
Highlights of the mission include:
-- Discovering long, filamentary structures in space, dotted with dense star-making knots of material.
-- Detecting definitively, for the first time, oxygen molecules in space, in addition to other never-before-seen molecules. By mapping the molecules in different regions, researchers are learning more about the life cycles of stars and planets and the origins of life.
-- Discovering high-speed outflows around central black holes in active galaxies, which may be clearing out surrounding regions and suppressing future star formation.
-- Opening new views on extremely distant galaxies that could be seen only with Herschel, and providing new information about their high rates of star formation.
-- Following the trail of water molecules from distant galaxies to the clouds of gas between stars to planet-forming solar systems.
-- Examining a comet in our own solar system and finding evidence comets could have brought a substantial fraction of water to Earth.
-- Together with NASA's Spitzer Space Telescope, discovering a large asteroid belt around the bright star Vega.
Other findings from the mission include the discovery of some of the youngest stars ever seen in the nearby Orion "cradle," and a peculiar planet-forming disk of material surrounding the star TW Hydra, indicating planet formation may happen over longer periods of time than expected. Herschel also has shown stars interact with their environment in many surprising ways, including leaving trails as they move through clouds of gas and dust.
The tiny red spot in this image is one of the most efficient star-making galaxies ever observed, converting gas into stars at the maximum possible rate. The galaxy is shown here in an image from NASA's Wide-field Infrared Survey Explorer (WISE), which first spotted the rare galaxy in infrared light.
Visible-light observations from NASA's Hubble Space Telescope (inset) reveal that the starlight in this galaxy is extraordinarily compact, with most of the light emitted by a region just a fraction of the size of the Milky Way galaxy. Within that tiny region, stars are forming at a rate hundreds of times that of our galaxy.
Astronomers have combined these star-formation and size measurements from WISE and Hubble, with a measurement of the amount of gas -- fuel for star formation -- from the IRAM Plateau de Bure interferometer to confirm that SDSSJ1504+54 is forming stars at the maximum theoretical rate. This is a case of star formation at its most extreme.
This artist’s impression shows the exotic double object that consists of a tiny, but very heavy neutron star that spins 25 times each second, orbited every two and a half hours by a white dwarf star. The neutron star is a pulsar named PSR J0348+0432 that is giving off radio waves that can be picked up on Earth by radio telescopes. Although this unusual pair is very interesting in its own right, it is also a unique laboratory for testing the limits of physical theories.
This system is radiating gravitational radiation, ripples in spacetime. Although these waves (shown as the grid in this picture) cannot be yet detected directly by astronomers on Earth they can be sensed indirectly by measuring the change in the orbit of the system as it loses energy.
As the pulsar is so small the relative sizes of the two objects are not drawn to scale.
This illustration shows a messy, chaotic galaxy undergoing bursts of star formation. This star formation is intense; it was known that it affects its host galaxy, but this new research shows it has an even greater effect than first thought. The winds created by these star formation processes stream out of the galaxy, ionizing gas at distances of up to 650,000 light-years from the galactic center.
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This NASA Hubble Space Telescope image of Comet (C/2012 S1) ISON was photographed on April 10, when the comet was slightly closer than Jupiter’s orbit at a distance of 386 million miles from the Sun (394 million miles from Earth).
Even at that great distance the comet is already active as sunlight warms the surface and causes frozen volatiles to sublimate. A detailed analysis of the dust coma surrounding the solid, icy nucleus reveals a strong, jet blasting dust particles off the sunward-facing side of the comet’s nucleus.
Preliminary measurements from the Hubble images suggest that the nucleus of ISON is no larger than three or four miles across. This is remarkably small considering the high level of activity observed in the comet so far, said researchers. Astronomers are using these images to measure the activity level of this comet and constrain the size of the nucleus, in order to predict the comet’s activity when it skims 700,000 miles above the sun's roiling surface on November 28.
The comet’s dusty coma, or head of the comet, is approximately 3,100 miles across, or 1.2 times the width of Australia. A dust tail extends more than 57,000 miles, far beyond Hubble’s field of view.
More careful analysis is currently underway to improve these measurements and to predict the possible outcome of the sungrazing perihelion passage of this comet.
This image was taken in visible light. The blue false color was added to bring out details in the comet structure.
ISON stands for International Scientific Optical Network, a group of observatories in ten countries who have organized to detect, monitor, and track objects in space. ISON is managed by the Keldysh Institute of Applied Mathematics, part of the Russian Academy of Sciences.
The Universe is rarely static, although the timescales involved can be very long. Since modern astronomical observations began we have been observing the birthplaces of new stars and planets, searching for and studying the subtle changes that help us to figure out what is happening within.
The bright spot located at the edge of the bluish fan-shaped structure in this Hubble image is a young star called V* PV Cephei, or PV Cep. It is a favorite target for amateur astronomers because the fan-shaped nebulosity, known as GM 1-29 or Gyulbudaghian’s Nebula, changes over a timescale of months. The brightness of the star has also varied over time.
Images of PV Cep taken in 1952 showed a nebulous streak, similar to a comet’s tail. However, these had vanished when new images of the star were obtained some twenty-five years later. Instead, the blue fan-shaped nebula had appeared. Twenty-five years is a very short period on cosmic timescales, so astronomers think that the mysterious streak may have been a temporary phenomenon, such as the remnants of a massive stellar flare — similar to the solar flares we are used to seeing in the Solar System.
At the same time as this was happening, the star itself was brightening. This provided the light to illuminate the newly formed fan-shaped nebula. This brightening might be related to the start of the hydrogen-burning phase of the star, which would mean that it was reaching maturity.
PV Cep is thought to be surrounded by a disc of gas and dust, which would stop light from escaping in all directions. The fan-like appearance is therefore probably a result of starlight escaping from the dust disc and projecting onto the nebula.
PV Cep is located in the northern constellation of Cepheus at a distance of over 1600 light-years from Earth.
This face-on color view of Enceladus was taken by the international Cassini spacecraft on 31 January 2011, from a distance of 81,000 km, and processed by amateur astronomer Gordan Ugarković.
This image shows the Orion B molecular cloud, a vast star-forming complex in the constellation Orion, as viewed at far-infrared wavelengths with ESA's Herschel Space Observatory. At about 1300 light-years, Orion B is one of the closest regions of star formation.
This massive stellar nursery reveals itself through the glow of cosmic dust in the interstellar material that pervades it. Heated by radiation from newborn stars, the dust shines brightly at far-infrared wavelengths, revealing a tangled network of filaments.
The bright yellow, white and pink areas in the image are the densest regions, where many protostars and newborn stars are found. Darker regions correspond to colder portions of the cloud where star formation is not as active. On the right-hand side of the image, the cloud exhibits a very sharp edge where the material in Orion B is being compressed by powerful winds blowing from clusters of massive stars located beyond the field of this image. These mighty stellar winds have sculpted the iconic Horsehead Nebula, glowing brightly on the right-hand edge of the Herschel image.
Herschel's far-infrared view of Orion B also shows other pockets of star-forming gas and dust nestled in the intricate structure of this cloud: NGC 2024, also known as the Flame Nebula, and NGC 2023 on the right-hand side of the image, to the left of the Horsehead Nebula; and NGC 2071 and NGC 2068 on the left-hand side of the image.
This false-color image combines data acquired with the PACS instrument at 70 micron (shown in blue) and 160 micron (shown in green) and with the SPIRE instrument at 250 micron (shown in red).
SN 1006: A supernova remnant whose progenitor explosion was seen from Earth over a thousand years ago.
A long Chandra observation reveals SN 1006 supernova remnant in exquisite detail. By overlapping ten different pointings of Chandra's field-of-view, astronomers have stitched together a cosmic tapestry of the debris field that was created when a white dwarf star exploded, sending its material hurtling into space as seen from Earth over a millennium ago. In this new Chandra image, low, medium, and higher-energy X-rays are colored red, green, and blue respectively. Since SN 1006 belongs to the class of supernovas used to measure the expansion of the Universe, the new Chandra data provide insight into these important objects.
Scale: Image is 34 arcmin across. (about 70 light years)
The diagram compares the planets of the inner solar system to Kepler-62, a five-planet system about 1,200 light-years from Earth in the constellation Lyra. The five planets of Kepler-62 orbit a star classified as a K2 dwarf, measuring just two thirds the size of the sun and only one fifth as bright. At seven billion years old, the star is somewhat older than the sun.
Much like our solar system, Kepler-62 is home to two habitable zone worlds, Kepler-62f and Kepler-62e. Kepler-62f orbits every 267 days and is only 40 percent larger than Earth, making it the smallest exoplanet known in the habitable zone of another star. The other habitable zone planet, Kepler-62e, orbits every 122 days and is roughly 60 percent larger than Earth.
The size of Kepler-62f is known, but its mass and composition are not. However, based on previous exoplanet discoveries of similar size that are rocky, scientists are able to determine its mass by association.
The two habitable zone worlds orbiting Kepler-62 have three interior companions, two larger than the size of Earth and one about the size of Mars. Kepler-62b, Kepler-62c and Kepler-62d, orbit every five, 12, and 18 days, respectively, making them very hot and inhospitable for life as we know it.
The artistic concepts of the Kepler-62 planets are the result of scientists and artists collaborating to help imagine the appearance of these distant worlds.
The diagram compares the planets of the inner solar system to Kepler-69, a two-planet system about 2,700 light-years from Earth in the constellation Cygnus. The two planets of Kepler-69 orbit a star that belongs to the same class as our sun, called G-type.
Kepler-69c, is 70 percent larger than the size of Earth, and is the smallest yet found to orbit in the habitable zone of a sun-like star. Astronomers are uncertain about the composition of Kepler-69c, but its orbit of 242 days around a sun-like star resembles that of our neighboring planet Venus. The companion planet, Kepler-69b, is just over twice the size of Earth and whizzes around its star once every 13 days.The artistic concepts of the Kepler-69 planets are the result of scientists and artists collaborating to help imagine the appearance of these distant worlds.
Astronomers have used NASA's Hubble Space Telescope to photograph the iconic Horsehead Nebula in a new, infrared light to mark the 23rd anniversary of the famous observatory's launch aboard the space shuttle Discovery on April 24, 1990.
Looking like an apparition rising from whitecaps of interstellar foam, the iconic Horsehead Nebula has graced astronomy books ever since its discovery more than a century ago. The nebula is a favorite target for amateur and professional astronomers. It is shadowy in optical light. It appears transparent and ethereal when seen at infrared wavelengths. The rich tapestry of the Horsehead Nebula pops out against the backdrop of Milky Way stars and distant galaxies that easily are visible in infrared light.
Hubble has been producing ground-breaking science for two decades. During that time, it has benefited from a slew of upgrades from space shuttle missions, including the 2009 addition of a new imaging workhorse, the high-resolution Wide Field Camera 3 that took the new portrait of the Horsehead.
This artist's impression shows the "starburst" galaxy HFLS3. The galaxy appears as little more than a faint, red smudge in images from the Herschel space observatory. But appearances can be deceiving for it is making stars more than 2,000 times faster than our own Milky Way galaxy, one of the highest star-formation rates ever seen in any galaxy. Amazingly, it is seen at a time when the universe was less than a billion years old, challenging galaxy evolution theories.
A team of astronomers has used ALMA (the Atacama Large Millimeter/submillimeter Array) to pinpoint the locations of over 100 of the most fertile star-forming galaxies in the early Universe.
The best map so far of these distant dusty galaxies was made using the Atacama Pathfinder Experiment (APEX), but the observations were not sharp enough to unambiguously identify these galaxies in images at other wavelengths. ALMA needed just two minutes per galaxy to pinpoint each one within a comparatively tiny region 200 times smaller than the broad APEX blobs, and with three times the sensitivity.
This image shows six of the galaxies as seen in the sharp new observations by ALMA (in red). The big red circles indicate the regions where galaxies had been detected by APEX. The earlier telescope did not have sharp enough images to pin down the identity of the galaxies, many candidates appear in each circle. The ALMA observations, at submillimeter wavelengths, are overlaid on an infrared view of the region as seen by the IRAC camera on the Spitzer Space Telescope (colored blue).
This graphic of Jupiter's moon Europa maps a relationship between the amount of energy deposited onto the moon from charged-particle bombardment and the chemical contents of ice deposits on the surface in five areas of the moon (labeled A through E).
Energetic ions and electrons tied to Jupiter's powerful magnetic field smack into Europa as the field sweeps around Jupiter. The magnetic field travels around Jupiter even faster than Europa orbits the planet. Most of the energetic particles hitting Europa strike the moon's "trailing hemisphere," the half facing away from the direction Europa travels in its orbit. The "leading hemisphere," facing in the direction of travel, receives fewer of the charged particles.
Researchers assessed the amount of sulfate hydrates -- compared with relatively pristine water -- in the surface ice in five widely distributed areas of Europa. They used data from observations made by the near infrared spectrometer (NIMS) instrument on NASA's Galileo spacecraft, which orbited Jupiter from 1995 to 2003. They found that the concentration of frozen sulfuric acid on the surface varies greatly. It ranges from undetectable levels near the center of Europa's leading hemisphere, to more than half of the surface material near the center of the trailing hemisphere. The concentration is closely related to the amount of energy received from electrons and sulfur ions striking the surface, with a distribution controlled by interactions between Jupiter and Europa's magnetic fields.
This pattern could provide direction for the best places to study the surface of Europa for learning about material churned up from the moon's subsurface, which includes a deep saltwater ocean beneath an icy shell. The portions of the surface least affected by the bombardment of charged particles from above are most likely to preserve the original chemical compounds that erupted from the interior. Understanding the chemical ingredients of Europa's subsurface ocean could help scientists determine whether, as many suspect, the ocean could have supported life in the past or even now.
The images of Europa used for the base maps of this figure were taken by the solid state imager on Galileo. The areas labeled A through E are the areas covered by five sets of NIMS observations, and color-coded with darker, bluer portions having more sulfate hydrates and brighter, pinker portions having more water ice. The mapped patterns for energy input are derived from models for the flux of electrons and ions delivered by Jupiter's magnetic field. The color-code key at the right is labeled in units of mega electron volts per square centimeter per second.
Globular clusters are relatively common in our sky, and generally look similar. However, this image, taken using the NASA/ESA Hubble Space Telescope, shows a unique example of such a cluster — Palomar 2.
Palomar 2 is part of a group of 15 globulars known as the Palomar clusters. These clusters, as the name suggests, were discovered in survey plates from the first Palomar Observatory Sky Survey in the 1950s, a project that involved some of the most well-known astronomers of the day, including Edwin Hubble. They were discovered quite late because they are so faint — each is either extremely remote, very heavily hidden behind blankets of dust, or has a very small number of remaining stars.
This particular cluster is unique in more than one way. For one, it is the only globular cluster that we see in this part of the sky, the northern constellation of Auriga (The Charioteer). Globular clusters orbit the center of a galaxy like the Milky Way in the same way that satellites circle around the Earth. This means that they normally lie closer in to the galactic center than we do, and so we almost always see them in the same region of the sky. Palomar 2 is an exception to this, as it is around five times further away from the center of the Milky Way than other clusters. It also lies in the opposite direction — further out than Earth — and so it is classed as an “outer halo” globular.
It is also unusual due to its brightness. The cluster is veiled by a mask of dust, dampening the apparent brightness of the stars within it and making it appear as a very faint burst of stars. The stunning NASA/ESA Hubble Space Telescope image above shows Palomar 2 in a way that could not be captured from smaller or ground-based telescopes — some amateur astronomers with large telescopes attempt to observe all of the obscure and well-hidden Palomar 15 as a challenge, to see how many they can pick out from the starry sky.
The soft glow in the picture above is NGC 2768, an elliptical galaxy located in the northern constellation of Ursa Major (The Great Bear). It appears here as a bright oval on the sky, surrounded by a wide, fuzzy cloud of material. This image, taken by the NASA/ESA Hubble Space Telescope, shows the dusty structure encircling the center of the galaxy, forming a knotted ring around the galaxy’s brightly glowing middle. Interestingly, this ring lies perpendicular to the plane of NGC 2768 itself, stretching up and out of the galaxy.
The dust in NGC 2768 forms an intricate network of knots and filaments. In the center of the galaxy are two tiny, S-shaped symmetric jets. These two flows of material travel outwards from the galactic center along curved paths, and are masked by the tangle of dark dust lanes that spans the body of the galaxy.
These jets are a sign of a very active center. NGC 2768 is an example of a Seyfert galaxy, an object with a supermassive black hole at its center. This speeds up and sucks in gas from the nearby space, creating a stream of material swirling inwards towards the black hole known as an accretion disc. This disk throws off material in very energetic outbursts, creating structures like the jets seen in the image above.
Kappa Coronae Borealis, based on Herschel PACS observations at 100 μm. North is up and east is left. The star is in the center of the frame (not visible in this graphic) with an excess of infrared emission detected around it, interpreted as a dusty debris disc containing asteroids and/or comets. The inclination of the planetary system is constrained at an angle of 60º from face-on.
This chart shows data from NASA's Kepler space telescope, which looks for planets by monitoring changes in the brightness of stars. As planets orbit in front of a star, they block the starlight, causing periodic dips. The plot on the left shows data collected by Kepler for a star called KOI-256, which is a small red dwarf. At first, astronomers thought the dip in starlight was due to a large planet passing in front of the star. But certain clues, such as the sharpness of the dip, indicated it was actually a white dwarf -- the dense, heavy remains of a star that was once like our sun. In fact, in the data shown at left, the white dwarf is passing behind the red dwarf, an event referred to as a secondary eclipse. The change in brightness is a result of the total light of the system dropping.
The plot on the right shows what happens when the white dwarf passes in front of, or transits, the star. The dip in brightness is incredibly subtle because the white dwarf, while just over half as massive as our sun, is only the size of Earth, much smaller than the red dwarf star. The blue line shows what would be expected given the size of the white dwarf. The red line reveals what was actually observed: the mass of the white dwarf is so great, that its gravity bent and magnified the light of the red star. Because the star's light was magnified, the transiting white dwarf blocked an even smaller fraction of the total starlight than it would have without the distortion. This effect, called gravitational lensing, allowed the researchers to precisely measure the mass of the white dwarf.
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