Tokyo, Kantō, Japan
May 20, 2012
Image Credit: Itsuo Inouye/AP Photo
March 31, 2017
Phoenicis Lacus region of Mars
Mars digital-image mosaic merged with color of the MC-17 quadrangle, Phoenicis Lacus region of Mars. Two of the four largest shield volcanoes on Mars are within the northwestern part, the south half of Pavonis Mons and Arsia Mons. The eastern part includes Syria and Sinai Plana. Most of the quadrangle forms the Tharsis plateau--the highest plateau on Mars; its elevation, 10 km, is twice that of the Tibetan Plateau, the highest plateau on Earth. Also in the northeastern part is Noctis Labyrinthus, a complex system of fault valleys at the west end of Valles Marineris. The south-central part is marked by the large fault system, Claritas Fossae. Latitude range -30 to 0 degrees, longitude range 90 to 135 degrees.
Image Credit: NASA/JPL/USGS
Explanation from: http://photojournal.jpl.nasa.gov/catalog/pia00177
Kepler-10b: A Scorched World
Kepler-10b is a scorched world, orbiting at a distance that's more than 20 times closer to its star than Mercury is to our own Sun. The daytime temperature's expected to be more than 2,500 degrees Fahrenheit, hotter than lava flows here on Earth. Intense radiation from the star has kept the planet from holding onto an atmosphere. Flecks of silicates and iron may be boiled off a molten surface and swept away by the stellar radiation, much like a comet's tail when its orbit brings it close to the Sun.
Image Credit: NASA/Kepler Mission/Dana Berry
Explanation from: https://www.nasa.gov/mission_pages/kepler/multimedia/images/kepler10_3.html
Lenticular Galaxy NGC 4526
This neat little galaxy is known as NGC 4526. Its dark lanes of dust and bright diffuse glow make the galaxy appear to hang like a halo in the emptiness of space in this new image from the NASA/ESA Hubble Space Telescope.
Although this image paints a picture of serenity, the galaxy is anything but. It is one of the brightest lenticular galaxies known, a category that lies somewhere between spirals and ellipticals. It has hosted two known supernova explosions, one in 1969 and another in 1994, and is known to have a colossal supermassive black hole at its centre that has the mass of 450 million Suns.
NGC 4526 is part of the Virgo cluster of galaxies. Ground-based observations of galaxies in this cluster have revealed that a quarter of these galaxies seem to have rapidly rotating discs of gas at their centres. The most spectacular of these is this galaxy, NGC 4526, whose spinning disc of gas, dust, and stars reaches out uniquely far from its heart, spanning some 7% of the galaxy's entire radius.
This disc is moving incredibly fast, spinning at more than 250 kilometres per second. The dynamics of this quickly whirling region were actually used to infer the mass of NGC 4526’s central black hole — a technique that had not been used before to constrain a galaxy’s central black hole.
This image was taken using Hubble’s Wide Field Planetary Camera 2.
Image Credit: ESA/Hubble & NASA, Judy Schmidt
Explanation from: https://www.spacetelescope.org/images/potw1442a/
The Lagoon Nebula
Like a Dali masterpiece, this image of Messier 8 from the NASA/ESA Hubble Space Telescope is both intensely colourful and distinctly surreal. Located in the constellation of Sagittarius (The Archer), this giant cloud of glowing interstellar gas is a stellar nursery that is also known as the Lagoon Nebula.
Although the name definitely suits the beauty of this object, “lagoon” does suggest tranquillity and there is nothing placid about the high-energy radiation causing these intricate clouds to glow. The massive stars hiding within the heart of the nebula give off enormous amounts of ultraviolet radiation, ionising the gas and causing it to shine colourfully, as well as sculpting the surrounding nebula into strange shapes. The result is an object around four to five thousand light-years away which, on a clear night, is faintly visible to the naked eye.
Since it was first recorded back in the 1747 this object has been photographed and analysed at many different wavelengths. By using infrared detectors it is possible to delve into the centre of these dusty regions to study the objects within. However, while this optical image, taken with the Advanced Camera for Surveys (ACS) on the Hubble Space Telescope, cannot pierce the obscuring matter it is undoubtedly one of the most visually impressive.
Messier 8 is an enormous structure — around 140 by 60 light-years in extent — to put this in perspective the orbit of Neptune stretches only about four light-hours from our own Sun.
This picture was created from exposures taken with the Wide Field Channel of the Advanced Camera for Surveys on Hubble. Light from glowing hydrogen (through the F658N filter) is coloured red. Light from ionised nitrogen (through the F660N filter) is coloured green and light through a yellow filter (F550M) is coloured blue. The exposure times through each filter are 1560 s, 1600 s and 400 s respectively. The blue-white flare at the lower left of the image is scattered light from a bright star just outside the field of view. The field of view is about 3.3 by 1.7 arcminutes.
Image Credit: ESA/Hubble & NASA
Explanation from: https://www.spacetelescope.org/images/potw1120a/
March 30, 2017
NGC 4424 & LEDA 213994 Galaxies
Some astronomical objects have endearing or quirky nicknames, inspired by mythology or their own appearance. Take, for example, the constellation of Orion (The Hunter), the Sombrero Galaxy, the Horsehead Nebula, or even the Milky Way. However, the vast majority of cosmic objects appear in astronomical catalogues, and are given rather less poetic names based on the order of their discovery.
Two galaxies are clearly visible in this Hubble image, the larger of which is NGC 4424. This galaxy is catalogued in the New General Catalogue of Nebulae and lusters of Stars (NGC), which was compiled in 1888. The NGC is one of the largest astronomical catalogues, which is why so many Hubble Pictures of the Week feature NGC objects. In total there are 7840 entries in the catalogue and they are also generally the larger, brighter, and more eye-catching objects in the night sky, and hence the ones more easily spotted by early stargazers.
The smaller, flatter, bright galaxy sitting just below NGC 4424 is named LEDA 213994. The Lyon-Meudon Extragalactic Database (LEDA) is far more modern than the NGC. Created in 1983 at the Lyon Observatory it contains millions of objects. However, many NGC objects still go by their initial names simply because they were christened within the NGC first. No astronomer can resist a good acronym, and “LEDA” is more appealing than “the LMED”, perhaps thanks to the old astronomical affinity with mythology when it comes to naming things: Leda was a princess in Ancient Greek mythology.
Image Credit: ESA/Hubble & NASA
Explanation from: https://www.spacetelescope.org/images/potw1713a/
Extreme Planets
This artist's concept depicts the pulsar planet system discovered in 1992 using the Arecibo radio telescope in Puerto Rico. Three pulsar planets - the first of any kind ever found outside our Solar System - circling a pulsar called PSR B1257+12. Pulsars are rapidly rotating neutron stars, which are the collapsed cores of exploded massive stars. They spin and pulse with radiation, much like a lighthouse beacon. Here, the pulsar's twisted magnetic fields are highlighted by the blue glow.
All three pulsar planets are shown in this picture; the farthest two from the pulsar (closest in this view) are about the size of Earth. Radiation from charged pulsar particles would probably rain down on the planets, causing their night skies to light up with auroras similar to our Northern Lights. One such aurora is illustrated on the planet at the bottom of the picture.
Since this landmark discovery, more than 160 extrasolar planets have been observed around stars that are burning nuclear fuel. These planets are still the only ones around a dead star. They also might be part of a second generation of planets, the first having been destroyed when their star blew up. The Spitzer Space Telescope's discovery of a dusty disk around a pulsar might represent the beginnings of a similarly "reborn" planetary system.
Image Credit: NASA/JPL-Caltech
Explanation from: http://photojournal.jpl.nasa.gov/catalog/PIA08042
The south pole of Jupiter
This enhanced-color image of Jupiter's south pole and its swirling atmosphere was created by citizen scientist Roman Tkachenko using data from the JunoCam imager on NASA's Juno spacecraft.
Juno acquired the image, looking directly at the Jovian south pole, on February 2, 2017, at 6:06 a.m. PST (9:06 a.m. EST) from an altitude of about 63,400 miles (102,100 kilometers) above Jupiter's cloud tops. Cyclones swirl around the south pole, and white oval storms can be seen near the limb -- the apparent edge of the planet.
Image Credit: NASA/JPL-Caltech/SwRI/MSSS/Roman Tkachenko
Explanation from: http://photojournal.jpl.nasa.gov/catalog/PIA21381
Earth seen from the International Space Station
ISS, Orbit of the Earth
September 2016
Image Credit: NASA/ESA
March 29, 2017
Cyclone Debbie
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| On March 28 at 03:42 UTC (1:42 p.m. AEST Queensland local time /Mar. 27 at 11:42 p.m. EST) NASA-NOAA's Suomi NPP satellite captured this visible image of Tropical Cyclone Debbie over eastern Australia. |
Before Debbie made landfall, NASA's Aqua satellite analyzed the temperatures in the storm on Mar. 27 at 0347 UTC (Mar. 26 at 11:47 pm. EST). The infrared imagery showed a large area of cloud top temperatures in thunderstorms around Debbie's eye as cold as near minus 63.1 degrees Celsius or minus 81.6 degrees Fahrenheit. Cloud top temperatures that cold have been shown to produce heavy rainfall.
Cyclone Debbie made landfall north of Proserpine at Airlie Beach on March 28, shortly after noon AEST/Queensland local time (0200 UTC/March 27 at 10 p.m. EST). The Australian Bureau of Meteorology noted wind gusts stronger than 160 mph (260 kph) were recorded near landfall.
The strong winds downed trees and powerlines. Power losses occurred in a large area between the towns of Bowen and Mackay, according to Ergon Energy. The Townsville airport and ocean ports were closed.
Shortly after Debbie's 30-mile-wide (50 km) eye made landfall, the VIIRS instrument aboard NASA-NOAA's Suomi NPP satellite captured a visible image of the storm at 03:42 UTC (1:42 p.m. AEST Queensland local time /Mar. 27 at 11:42 p.m. EST). The image showed a thick band of powerful thunderstorms wrapped around the cloud-filled eye.
At 11:58 p.m. AEST/Queensland local time (9:58 a.m. EST/U.S.), the Australian Bureau of Meteorology (ABM) noted that the Warning Zone extended from Bowen to St Lawrence, including Mackay and the Whitsunday Islands, and extending inland to Mount Coolon and Moranbah.
At that time, ABM noted that maximum sustained winds near Debbie's center were near 52.8 mph (85 kph) with higher gusts. Debbie was centered near 20.8 degrees south latitude and 147.5 degrees east longitude, about 71.4 miles (115 kilometers) west southwest of Proserpine and 24.8 miles (40 kilometers) southwest of Collinsville. Debbie continued to move inland in a west-southwesterly direction at (9.3 mph) 15 kph.
ABM noted "Tropical cyclone Debbie is expected to weaken further to a tropical low during the next few hours. During the day today, this remnant low will curve from the current southwesterly motion to a more southerly track over inland Queensland.
Although the peak winds near Debbie's center are weakening rapidly tonight, heavy rainfall is expected to continue across the region for the next 12 to 24 hours, gradually contracting southwards with the system."
Image Credit: NASA/NOAA
Explanation from: https://www.nasa.gov/feature/goddard/2017/91p-southern-pacific-ocean
Stars Born in Winds from Supermassive Black Holes
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| Artist’s impression of a galaxy forming stars within powerful outflows of material blasted out from supermassive black holes at its core. Results from ESO’s Very Large Telescope are the first confirmed observations of stars forming in this kind of extreme environment. The discovery has many consequences for understanding galaxy properties and evolution. |
Observations using ESO’s Very Large Telescope have revealed stars forming within powerful outflows of material blasted out from supermassive black holes at the cores of galaxies. These are the first confirmed observations of stars forming in this kind of extreme environment. The discovery has many consequences for understanding galaxy properties and evolution. The results are published in the journal Nature.
A UK-led group of European astronomers used the MUSE and X-shooter instruments on the Very Large Telescope (VLT) at ESO’s Paranal Observatory in Chile to study an ongoing collision between two galaxies, known collectively as IRAS F23128-5919, that lie around 600 million light-years from Earth. The group observed the colossal winds of material — or outflows — that originate near the supermassive black hole at the heart of the pair’s southern galaxy, and have found the first clear evidence that stars are being born within them.
Such galactic outflows are driven by the huge energy output from the active and turbulent centres of galaxies. Supermassive black holes lurk in the cores of most galaxies, and when they gobble up matter they also heat the surrounding gas and expel it from the host galaxy in powerful, dense winds.
“Astronomers have thought for a while that conditions within these outflows could be right for star formation, but no one has seen it actually happening as it’s a very difficult observation,” comments team leader Roberto Maiolino from the University of Cambridge. “Our results are exciting because they show unambiguously that stars are being created inside these outflows.”
The group set out to study stars in the outflow directly, as well as the gas that surrounds them. By using two of the world-leading VLT spectroscopic instruments, MUSE and X-shooter, they could carry out a very detailed study of the properties of the emitted light to determine its source.
Radiation from young stars is known to cause nearby gas clouds to glow in a particular way. The extreme sensitivity of X-shooter allowed the team to rule out other possible causes of this illumination, including gas shocks or the active nucleus of the galaxy.
The group then made an unmistakable direct detection of an infant stellar population in the outflow. These stars are thought to be less than a few tens of millions of years old, and preliminary analysis suggests that they are hotter and brighter than stars formed in less extreme environments such as the galactic disc.
As further evidence, the astronomers also determined the motion and velocity of these stars. The light from most of the region’s stars indicates that they are travelling at very large velocities away from the galaxy centre — as would make sense for objects caught in a stream of fast-moving material.
Co-author Helen Russell (Institute of Astronomy, Cambridge, UK) expands: “The stars that form in the wind close to the galaxy centre might slow down and even start heading back inwards, but the stars that form further out in the flow experience less deceleration and can even fly off out of the galaxy altogether.”
The discovery provides new and exciting information that could better our understanding of some astrophysics, including how certain galaxies obtain their shapes; how intergalactic space becomes enriched with heavy elements; and even from where unexplained cosmic infrared background radiation may arise.
Maiolino is excited for the future: “If star formation is really occurring in most galactic outflows, as some theories predict, then this would provide a completely new scenario for our understanding of galaxy evolution.”
Image Credit: ESO/M. Kornmesser
Explanation from: https://www.eso.org/public/news/eso1710/
Milky Way Galaxy seen over VLT’s four 8.2-metre Unit Telescopes
ESO's Very Large Telescope (VLT) looks more like a very small telescope in this image! From this perspective, it is difficult to make out the silhouettes of the VLT’s four 8.2-metre Unit Telescopes, which sit atop Cerro Paranal in the Chilean Atacama Desert.
The VLT’s location was very carefully selected. It is vital for the site to be as dry as possible, as water vapour can absorb infrared light and degrade observations. In order to reduce the effects of Earth’s atmosphere as far as possible, the VLT is at 2600 metres above sea level, minimising the amount of atmosphere sitting between it and the stars.
Due to its remote location, Paranal manages to be mostly undisturbed and light-free. Even the winding roads that lead through the Atacama Desert to the observation site are dimly lit to avoid unnecessary light pollution.
In this image, a trail of stars cuts across the the night sky like smoke rising from a celestial chimney. This is our home galaxy, the Milky Way. Towards the top of the image you can see a brighter and wider section — this is the star-filled galactic bulge, which sits at the heart of the Milky Way.
Image Credit: ESO/B. Tafreshi
Explanation from: https://www.eso.org/public/images/potw1713a/
Was 49 Galaxy Merger
A supermassive black hole inside a tiny galaxy is challenging scientists' ideas about what happens when two galaxies become one.
Was 49 is the name of a system consisting of a large disk galaxy, referred to as Was 49a, merging with a much smaller "dwarf" galaxy called Was 49b. The dwarf galaxy rotates within the larger galaxy's disk, about 26,000 light-years from its center. Thanks to NASA's Nuclear Spectroscopic Telescope Array (NuSTAR) mission, scientists have discovered that the dwarf galaxy is so luminous in high-energy X-rays, it must host a supermassive black hole much larger and more powerful than expected.
"This is a completely unique system and runs contrary to what we understand of galaxy mergers," said Nathan Secrest, lead author of the study and postdoctoral fellow at the U.S. Naval Research Laboratory in Washington.
Data from NuSTAR and the Sloan Digital Sky Survey suggest that the mass of the dwarf galaxy's black hole is huge, compared to similarly sized galaxies, at more than 2 percent of the galaxy's own mass.
"We didn't think that dwarf galaxies hosted supermassive black holes this big," Secrest said. "This black hole could be hundreds of times more massive than what we would expect for a galaxy of this size, depending on how the galaxy evolved in relation to other galaxies.”
The dwarf galaxy's black hole is the engine of an active galactic nucleus (AGN), a cosmic phenomenon in which extremely high-energy radiation bursts forth as a black hole devours gas and dust. This particular AGN appears to be covered by a donut-shaped structure made of gas and dust. NASA's Chandra and Swift missions were used to further characterize the X-ray emission.
Normally, when two galaxies start to merge, the larger galaxy's central black hole becomes active, voraciously gobbling gas and dust, and spewing out high-energy X-rays as matter gets converted into energy. That is because, as galaxies approach each other, their gravitational interactions create a torque that funnels gas into the larger galaxy's central black hole. But in this case, the smaller galaxy hosts a more luminous AGN with a more active supermassive black hole, and the larger galaxy's central black hole is relatively quiet.
An optical image of the Was 49 system, compiled using observations from the Discovery Channel Telescope in Happy Jack, Arizona, uses the same color filters as the Sloan Digital Sky Survey. Since Was 49 is so far away, these colors are optimized to separate highly-ionized gas emission, such as the pink-colored region around the feeding supermassive black hole, from normal starlight, shown in green. This allowed astronomers to more accurately determine the size of the dwarf galaxy that hosts the supermassive black hole.
The pink-colored emission stands out in a new image because of the intense ionizing radiation emanating from the powerful AGN. Buried within this region of intense ionization is a faint collection of stars, believed to be part of the galaxy surrounding the enormous black hole. These striking features lie on the outskirts of the much larger spiral galaxy Was 49a, which appears greenish in the image due to the distance to the galaxy and the optical filters used.
Scientists are still trying to figure out why the supermassive black hole of dwarf galaxy Was 49b is so big. It may have already been large before the merger began, or it may have grown during the very early phase of the merger.
"This study is important because it may give new insight into how supermassive black holes form and grow in such systems," Secrest said. “By examining systems like this, we may find clues as to how our own galaxy’s supermassive black hole formed.”
In several hundred million years, the black holes of the large and small galaxies will merge into one enormous beast.
Image Credit: DCT/NRL
Explanation from: https://www.nasa.gov/feature/jpl/nustar-probes-puzzling-galaxy-merger
CoRoT-2a: Star Blasts Planet With X-rays
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| This artist's representation shows the CoRoT-2 system, which is found about 880 light years from Earth. The system, which is estimated to be between 100 and 300 million years old, contains a star and a planet in close orbit around it. The separation between the star and the planet is only three percent of the distance between the Earth and the Sun, causing some exotic effects not seen in our solar system. The illustration shows the material, in blue, being stripped off the planet as X-rays from the star pummel the planet. |
- A star is blasting a planet in its orbit with an extremely high level of X-rays.
- This high-energy radiation is eroding the planet at a rate of 5 million tons of material per second.
- The planet, in turn, may be speeding up the star's rotation, which keeps the star's magnetic fields very active.
This graphic contains an image and illustration of a nearby star, named CoRoT-2a, which has a planet in close orbit around it. The separation between the star and planet is only about 3 percent of the distance between the Earth and the Sun, causing some exotic effects not seen in our solar system.
The planet-hosting star is located in the center of the image. Data from NASA's Chandra X-ray Observatory are shown in purple, along with optical and infrared data from the Panchromatic Robotic Optical Monitoring and Polarimetry Telescopes (PROMPT) and the Two Micron All Sky Survey (2MASS). CoRoT-2a is surrounded by a purple glow showing that it is an X-ray source.
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| A nearby star is pummeling a companion planet with a barrage of X-rays a hundred thousand times more intense than the Earth receives from the Sun. New data from NASA's Chandra X-ray Observatory and the European Southern Observatory's Very Large Telescope suggest that high-energy radiation is evaporating about 5 million tons of matter from the planet every second. This result gives insight into the difficult survival path for some planets. This sequence shows images of a nearby star named CoRoT-2a. The composite image contains X-rays from Chandra (purple) of CoRoT-2a along with optical and infrared data of the field of view in which the star is found. Not seen in these images -- but still detectable in the data -- is a planet known as CoRoT-2b in an extremely close orbit around the star. The Chandra data indicate that the planet is being blasted by X-rays with such intensity that some 5 million tons of material are being eroded from CoRoT-2a every second. |
This star is pummeling its companion planet -- not visible in this image -- with a barrage of X-rays a hundred thousand times more intense than the Earth receives from the Sun. Data from Chandra suggest that high-energy radiation from CoRoT-2a is evaporating about 5 million tons of matter from the nearby planet every second, giving insight into the difficult survival path for some planets. The artist's representation shows the material, in blue, being stripped off the planet.
The Chandra observations provide evidence that CoRoT-2a is a very active star, with bright X-ray emission produced by powerful, turbulent magnetic fields. This magnetic activity is represented by the prominences and eruptions on the surface of the star in the illustration.
Such strong activity is usually found in much younger stars and may be caused by the proximity of the planet. The planet may be speeding up the star's rotation, causing its magnetic fields to remain active longer than expected. Support for this idea comes from observations of a likely companion star to CoRoT-2a that orbits at a distance about a thousand times greater than the distance between the Earth and the Sun. This star is visible in the image as the faint, nearby star located below and to the right of CoRoT-2a. It is also shown as the bright background star in the illustration. This star is not detected in X-rays, perhaps because it does not have a close-in planet like CoRoT-2b to cause it to stay active.
The planet, CoRoT-2b, was discovered by the French Space Agency's Convection, Rotation and planetary Transits (CoRoT) satellite in 2008. It is located about 880 light years from Earth and has a mass about 3 time that of Jupiter.
Image Credit: X-ray: NASA/CXC/Univ of Hamburg/S.Schröter et al; Optical: NASA/NSF/IPAC-Caltech/UMass/2MASS, UNC/CTIO/PROMPT; Illustration: NASA/CXC/M.Weiss
Explanation from: http://chandra.harvard.edu/photo/2011/corot/
