Asteroid 1998 QE2 and Moon

Radar data of asteroid 1998 QE2 obtained on May 29, 2013. The small moving white dot is the moon, or satellite, orbiting asteroid 1998 QE2. A sequence of radar images of asteroid 1998 QE2 was obtained on the evening of May 29, 2013, by NASA scientists using the 230-foot (70-meter) Deep Space Network antenna at Goldstone, California, when the asteroid was about 3.75 million miles (6 million kilometers) from Earth, which is 15.6 lunar distances.

The radar imagery revealed that 1998 QE2 is a binary asteroid. In the near-Earth population, about 16 percent of asteroids that are about 655 feet (200 meters) or larger are binary or triple systems. Radar images suggest that the main body, or primary, is approximately 1.7 miles (2.7 kilometers) in diameter and has a rotation period of less than four hours. Also revealed in the radar imagery of 1998 QE2 are several dark surface features that suggest large concavities. The preliminary estimate for the size of the asteroid's satellite, or moon, is approximately 2,000 feet (600 meters) wide. The radar collage covers a little bit more than two hours.

The radar observations were led by scientist Marina Brozovic of NASA's Jet Propulsion Laboratory, Pasadena, California.

The closest approach of the asteroid occurs on May 31 at 1:59 p.m. Pacific (4:59 p.m. Eastern / 20:59 UTC), when the asteroid will get no closer than about 3.6 million miles (5.8 million kilometers), or about 15 times the distance between Earth and the Moon. This is the closest approach the asteroid will make to Earth for at least the next two centuries. Asteroid 1998 QE2 was discovered on August 19, 1998, by the Massachusetts Institute of Technology Lincoln Near Earth Asteroid Research (LINEAR) program near Socorro, New Mexico.

Video credit: NASA/JPL-Caltech/GSSR

Note: For more information, see:
* NASA Radar Reveals Asteroid Has Its Own Moon
* Radar Movies Highlight Asteroid 1998 QE2 and Its Moon
* Approaching Asteroid Has Its Own Moon
* Big Asteroid Flyby
* Asteroid Moon Movie.

NGC 6752

This image from the Wide Field Imager on the MPG/ESO 2.2-meter telescope at the La Silla Observatory in Chile shows the globular star cluster NGC 6752 in the southern constellation of Pavo (The Peacock). Studies of this cluster using ESO’s Very Large Telescope have unexpectedly revealed that many of the stars do not undergo mass-loss at the end of their lives.

Photo credit: ESO

Note: For more information, see Low Sodium Diet Key to Old Age for Stars.

ESO 576-69

This new image from the NASA/ESA Hubble Space Telescope captures an ongoing cosmic collision between two galaxies — a spiral galaxy is in the process of colliding with a lenticular galaxy. The collision looks almost as if it is popping out of the screen in 3D, with parts of the spiral arms clearly embracing the lenticular galaxy’s bulge.

The image also reveals further evidence of the collision. There is a bright stream of stars coming out from the merging galaxies, extending out towards the right of the image. The bright spot in the middle of the plume, known as ESO 576-69, is what makes this image unique. This spot is believed to be the nucleus of the former spiral galaxy, which was ejected from the system during the collision and is now being shredded by tidal forces to produce the visible stellar stream.

Photo credit: ESA/Hubble & NASA; Acknowledgement: Luca Limatola

Messier 57 - The Ring Nebula

New view of the Ring Nebula (also known as Messier 57 or NGC 6720) by the Hubble Space Telescope.

From Earth’s perspective, the nebula looks like a simple elliptical shape with a shaggy boundary. However, new observations combining existing ground-based data with new NASA/ESA Hubble Space Telescope data show that the nebula is shaped like a distorted doughnut. This doughnut has a rugby-ball-shaped region of lower-density material slotted into in its central ‘gap’, stretching towards and away from us.

Photo credit: NASA, ESA, and C. Robert O'Dell (Vanderbilt University)

Big Weather on Hot Jupiters

Among the hundreds of new planets discovered by NASA's Kepler spacecraft are a class of exotic worlds known as "hot Jupiters." Unlike the giant planets of our own solar system, which remain at a safe distance from the sun, these worlds are reckless visitors to their parent stars. They speed around in orbits a fraction the size of Mercury’s, blasted on just one-side by starlight hundreds of times more intense than the gentle heating experienced by Jupiter here at home.

Meteorologists watching this video are probably wondering what kind of weather a world like that might have. The short answer is "big."

Heather Knutson of Caltech made the first weather map of a hot Jupiter in 2007.

"It's not as simple as taking a picture and--voila!—we see the weather," says Knutson. These planets are hundreds of light years from Earth and they are nearly overwhelmed by the glare of their parent stars. "Even to see the planet as a single pixel next to the star would be a huge accomplishment."

Instead, Knutson and colleagues use a trick dreamed up by Nick Cowan of Northwestern University. The key, she explains, is that "most hot Jupiters are tidally locked to their stars. This means they have a permanent dayside and a permanent night side. As we watch them orbit from our vantage point on Earth, the planets exhibit phases--e.g., crescent, gibbous and full. By measuring the infrared brightness of the planet as a function of its phase, we can make a rudimentary map of temperature vs. longitude."

This exoplanet weather map shows temperatures on a hot Jupiter known as "HAT-P-2b".

NASA’s Spitzer Space Telescope is the only infrared observatory with the sensitivity to do this work. Since Knutson kick-started the research in 2007, nearly a dozen hot Jupiters have been mapped by astronomers using Spitzer.

The most recent study, led by Nikole Lewis, a NASA Sagan Exoplanet Fellow working at MIT, shows a gas giant named HAT-P-2b. "We can see daytime temperatures as high as 2400 K," says Lewis, "while the nightside drops below 1200K. Even at night," she marvels, "this planet is ten times hotter than Jupiter."

These exoplanet maps may seem crude compared to what we’re accustomed to on Earth, but they are a fantastic accomplishment considering that the planets are trillions of miles away.

The maps show huge day-night temperature differences typically exceeding 1000 degrees. Researchers believe these thermal gradients drive ferocious winds blowing thousands of miles per hour.

Without regular pictures, researchers can’t say what this kind of windy weather looks like. Nevertheless, Knutson is willing to speculate using climate models of Jupiter as a guide.

"Weather on hot Jupiters," she predicts, "is really big."

Over the years, planetary scientists have developed computer models to reproduce the storms and cloud belts in Jupiter’s atmosphere. If you take those models and turn up the heat, and slow down the rotation to match the tidally-locked spin of a hot Jupiter, weather patterns become super-sized. For instance, on a hot Jupiter the Great Red Spot might grow as large as a quarter the size of the planet and manifest itself in both the northern and southern hemispheres.

"Just imagine what that would look like--a pair of giant eyes staring out into space!" says Lewis.

Meanwhile, Jupiter’s famous belts would widen so much that only two or three would fit across the planet’s girth.

Ordinary clouds of water and methane couldn’t form in such a hot environment. Instead, Knutson speculates that hot Jupiters might have clouds made of silicate—that is, "rock clouds."

"Silicates are predicted to condense in such an environment," she says. "We're already getting some hints that clouds might be common on these planets, but we don’t yet know if they’re made of rock."

For now just one thing is certain: The meteorology of hot Jupiters is out of this world.

Video credit: NASA

Galactic Formation - Cosmic Swirly Straws

Created with the help of supercomputers, this simulation shows the formation of a massive galaxy during the first 2 billion years of the universe. Hydrogen gas is gray, young stars appear blue, and older stars are red. The simulation reveals that gas flows into galaxies along filaments akin to cosmic bendy, or swirly, straws.

Video credit: N-Body Shop at University of Washington

Note: For more information, see Galaxies Fed by Funnels of Fuel.

Fifteen Years of the Very Large Telescope

This selection of images — one per year in the life of the VLT — gives a taste of its huge scope and scientific productivity since first light in May 1998. The images are as follows: 1998: NGC 1232 (eso9845), 1999: NGC 3603 (eso9946), 2000: Messier 104, the Sombrero Galaxy (eso0007), 2001: Messier 16 in the infrared (eso0142), 2002: the Horsehead Nebula (eso0202), 2003: NGC 613 (eso0338), 2004: first candidate exoplanet image (eso0428), 2005: NGC 1097 center (eso0534), 2006: NGC 1313 (eso0643), 2007: ESO 593-IG 008 (eso0755), 2008: center of the Milky Way (eso0846), 2009: the Jewel Box cluster (eso0940), 2010: Messier 17 in the infrared (potw1044a), 2011: the Eyes galaxies (eso1131), 2012: the Carina Nebula in the infrared (eso1208) and 2013: IC 2944 (eso1322).

Image credits: ESO/P.D. Barthel/M. McCaughrean/M. Andersen/S. Gillessen et al./Y. Beletsky/R. Chini/T. Preibisch

Note: For more information, see ESO's Very Large Telescope Celebrates 15 Years of Success.

SGR 0418+5729

SGR 0418+5729: A magnetar located in our galaxy, about 6,500 light years from Earth.

This graphic shows a magnetar called SGR 0418+5729 (SGR 0418 for short), a type of neutron star that has a relatively slow spin rate and generates occasional large blasts of X-rays. Most magnetars have extremely high magnetic fields on their surface that are ten to a thousand times stronger than for the average neutron star. New data from NASA’s Chandra X-ray Observatory, ESA’s XMM-Newton and NASA's Swift and RXTE satellites shows that SGR 0418 is exceptional, with a surface magnetic field similar to that of mainstream neutron stars. In the image on the left, data from Chandra shows SGR 0418 as a pink source in the middle. Optical data from the William Herschel telescope in La Palma and infrared data from NASA’s Spitzer Space Telescope are shown in red, green and blue. On the right is an artist’s impression giving a close-up view of SGR 0418. This illustration highlights the weak surface magnetic field of the magnetar, and the relatively strong, wound-up magnetic field lurking in the hotter interior of the star. SGR 0418 is located about 6,500 light years from Earth.

Scale: Image is about 2 arcmin across. (about 3 light years).

Image credit: X-ray: NASA/CXC/CSIC-IEEC/N.Rea et al; Optical: Isaac Newton Group of Telescopes, La
Palma/WHT; Infrared: NASA/JPL-Caltech; Illustration: NASA/CXC/M.Weiss.

Note: For more information, see SGR 0418+5729: A Hidden Population of Exotic Neutron Stars.

Galactic Merger HXMM01

Several telescopes have teamed up to discover a rare and massive merging of two galaxies that took place when the universe was just 3 billion years old (its current age is about 14 billion years). The galaxies, collectively called HXMM01, are churning out the equivalent of 2,000 suns a year. By comparison, our Milky Way hatches about two to three suns a year. The total number of stars in both colliding galaxies averages out to about 400 billion suns.

The Herschel Space Observatory first spotted the colliding duo in images taken with longer-wavelength infrared light, as shown in the image at left. Follow-up observations from many telescopes helped determine the extreme degree of star-formation taking place in the merger, as well as its incredible mass.

The image at right (Figure 1) shows a close-up view, with the merging galaxies circled. The red data are from the Smithsonian Astrophysical Observatory's Submillimeter Array atop Mauna Kea, Hawaii, and show dust-enshrouded regions of star formation. The green data, taken by the National Radio Astronomy Observatory's Very Large Array, near Socorro, New Mexico, show carbon monoxide gas in the galaxies. In addition, the blue shows starlight.

The blue blobs outside of the circle are galaxies located much closer to us. These visible-light observations are from NASA's Hubble Space Telescope and the W.M. Keck Observatory atop Mauna Kea, Hawaii.

Image credit: ESA/NASA/JPL-Caltech/UC Irvine/STScI/Keck/NRAO/SAO

Note: For more information, see Herschel Space Observatory Finds Galaxy Mega Merger.

Bright Explosion on the Moon

For the past 8 years, NASA astronomers have been monitoring the Moon for signs of explosions caused by meteoroids hitting the lunar surface. "Lunar meteor showers" have turned out to be more common than anyone expected, with hundreds of detectable impacts occurring every year.

They've just seen the biggest explosion in the history of the program.

"On March 17, 2013, an object about the size of a small boulder hit the lunar surface in Mare Imbrium," says Bill Cooke of NASA's Meteoroid Environment Office. "It exploded in a flash nearly 10 times as bright as anything we've ever seen before."

Anyone looking at the Moon at the moment of impact could have seen the explosion--no telescope required. For about one second, the impact site was glowing like a 4th magnitude star.

Ron Suggs, an analyst at the Marshall Space Flight Center, was the first to notice the impact in a digital video recorded by one of the monitoring program's 14-inch telescopes. "It jumped right out at me, it was so bright," he recalls.

The 40 kg meteoroid measuring 0.3 to 0.4 meters wide hit the Moon traveling 56,000 mph. The resulting explosion1 packed as much punch as 5 tons of TNT.

Cooke believes the lunar impact might have been part of a much larger event.

"On the night of March 17, NASA and University of Western Ontario all-sky cameras picked up an unusual number of deep-penetrating meteors right here on Earth," he says. "These fireballs were traveling along nearly identical orbits between Earth and the asteroid belt."

This means Earth and the Moon were pelted by meteoroids at about the same time.

“My working hypothesis is that the two events are related, and that this constitutes a short duration cluster of material encountered by the Earth-Moon system," says Cooke.

One of the goals of the lunar monitoring program is to identify new streams of space debris that pose a potential threat to the Earth-Moon system. The March 17th event seems to be a good candidate.

Controllers of NASA's Lunar Reconnaissance Orbiter have been notified of the strike. The crater could be as wide as 20 meters, which would make it an easy target for LRO the next time the spacecraft passes over the impact site. Comparing the size of the crater to the brightness of the flash would give researchers a valuable "ground truth" measurement to validate lunar impact models.

Unlike Earth, which has an atmosphere to protect it, the Moon is airless and exposed. "Lunar meteors" crash into the ground with fair frequency. Since the monitoring program began in 2005, NASA’s lunar impact team has detected more than 300 strikes, most orders of magnitude fainter than the March 17th event. Statistically speaking, more than half of all lunar meteors come from known meteoroid streams such as the Perseids and Leonids. The rest are sporadic meteors--random bits of comet and asteroid debris of unknown parentage.

U.S. Space Exploration Policy eventually calls for extended astronaut stays on the lunar surface. Identifying the sources of lunar meteors and measuring their impact rates gives future lunar explorers an idea of what to expect. Is it safe to go on a moonwalk, or not? The middle of March might be a good time to stay inside.

"We'll be keeping an eye out for signs of a repeat performance next year when the Earth-Moon system passes through the same region of space," says Cooke. “Meanwhile, our analysis of the March 17th event continues.”

Footnote: (1) The Moon has no oxygen atmosphere, so how can something explode? Lunar meteors don't require oxygen or combustion to make themselves visible. They hit the ground with so much kinetic energy that even a pebble can make a crater several feet wide. The flash of light comes not from combustion but rather from the thermal glow of molten rock and hot vapors at the impact site.

Video credit: NASA

4C+29.30: Black Hole Powered Jets Plow Into Galaxy

4C+29.30: A galaxy located about 850 million light years from Earth.

The intense gravity of a supermassive black hole can be tapped to produce immense power in the form of jets moving at millions of miles per hour. A composite image shows this happening in the galaxy known as 4C+29.30 where X-rays from Chandra (blue) have been combined with optical (gold) and radio (pink) data. The X-rays trace the location of superheated gas around the black hole, which is estimated to weigh 100 million times the mass of our Sun. Some of this material may eventually be consumed by the black hole, and the magnetized, whirlpool of gas near the black hole could in turn, trigger more output to the radio jet. The optical light image shows the stars in this galaxy. A torus of gas and dust surrounds the black hole and blocks most of the optical light coming from there. Because of this, astronomers refer to this type of source as a hidden or buried black hole.

Scale: Image is 45 arcsec on a side (180,000 light years).

Image credit: X-ray: NASA/CXC/SAO/A.Siemiginowska et al, Optical: NASA/STScI; Radio: NSF/NRAO/VLA)

Note: For more information, see 4C+29.30: Black Hole Powered Jets Plow Into Galaxy.

A Whiff of Dark Matter on the ISS

In science fiction, finding antimatter on board your spaceship is not good news. Usually, it means you're moments away from an explosion.

In real life, though, finding antimatter could lead to a Nobel Prize.

On April 3rd, researchers led by Nobel Laureate Samuel Ting of MIT announced that the Alpha Magnetic Spectrometer, a particle detector operating onboard the International Space Station since 2011, has counted more than 400,000 positrons, the antimatter equivalent of electrons. There’s no danger of an explosion, but the discovery is sending shock waves through the scientific community.

"These data show the existence of a new physical phenomenon," wrote Ting and colleagues in an article published in the Physical Review Letters. "It could be a sign of dark matter."

The Alpha Magnetic Spectrometer (“AMS” for short) was delivered to the ISS by the space shuttle Endeavour on its final flight in May 2011. In its first 18 months of operations, from May 19, 2011 to December 10, 2012, the AMS analyzed 25 billion cosmic ray events. Of these, an unprecedented number were unambiguously identified as positrons.

Cosmic rays are subatomic particles such as protons and helium nuclei accelerated to near-light speed by supernova explosions and other violent events in the cosmos. Researchers have long known that cosmic rays contain a sprinkling of antimatter. Italy's PAMELA satellite detected high-energy positrons in 2009, and NASA's Fermi gamma-ray observatory confirmed the find two years later.

But where do the positrons come from? The Universe is almost completely devoid of antimatter, so the positron fraction of cosmic ray electrons--as much as 10%--is a little surprising.

One idea is dark matter. Astronomers know that the vast majority of the material Universe is actually made of dark matter rather than ordinary matter. They just don't know what dark matter is. It exerts gravity, but emits no light, which makes it devilishly difficult to study.

The Alpha Magnetic Spectrometer mounted outside the International Space Station.

A leading theory holds that dark matter is made of a particle called the neutralino. Collisions between neutralinos should produce a large number of high-energy positrons, which the AMS should be able to detect with unprecedented sensitivity.

"The accuracy of our measurements is 1%, which is excellent, and we have statistics unmatched by any other spacecraft," says Ting.

"So far the evidence supports the hypothesis of dark matter. But," he cautions," it does not rule out another possibility--pulsars."

Pulsars are strongly-magnetized neutron stars formed in the aftermath of supernova explosions. They can spin on their axes thousands of times a second, flinging particles into space with fantastic energies that accelerators on Earth can't match. Among these particles are pairs of electrons and positrons.

AMS can distinguish between pulsars and dark matter--but not yet. "We need more data at higher energies to decide which is the correct explanation," says Ting. "It is only a matter of time, perhaps months or a few years."

Built by scientists from 16 countries with support from the US Department of Energy, the Alpha Magnetic Spectrometer will continue operating for the rest of the life of the space station ­ at least until 2020. Between now and then, the mystery of dark matter could be solved, once and for all.

Video credit: NASA

NASA Scientists Find Moon, Asteroids Share History

Scientists have now discovered that studying meteorites from the giant asteroid Vesta helps them understand the event known as the "lunar cataclysm," when a repositioning of the gas giant planets destabilized a portion of the asteroid belt and triggered a solar-system-wide bombardment.

NASA and international researchers have discovered that Earth's moon has more in common than previously thought with large asteroids roaming our solar system.

Scientists from NASA's Lunar Science Institute (NLSI) in Moffett Field, California, discovered that the same population of high-speed projectiles that impacted our lunar neighbor four billion years ago, also hit the giant asteroid Vesta and perhaps other large asteroids.

The research unveils an unexpected link between Vesta and the moon, and provides new means for studying the early bombardment history of terrestrial planets. The findings are published in the March issue of Nature Geoscience.

"It's always intriguing when interdisciplinary research changes the way we understand the history of our solar system," said Yvonne Pendleton, NLSI director. "Although the moon is located far from Vesta, which is in the main asteroid belt between the orbits of Mars and Jupiter, they seem to share some of the same bombardment history."

The findings support the theory that the repositioning of gas giant planets like Jupiter and Saturn from their original orbits to their current location destabilized portions of the asteroid belt and triggered a solar system-wide bombardment of asteroids billions of years ago, called the lunar cataclysm.

The research provides new constraints on the start and duration of the lunar cataclysm, and demonstrates that the cataclysm was an event that affected not only the inner solar system planets, but the asteroid belt as well.

The moon rocks brought back by NASA Apollo astronauts have long been used to study the bombardment history of the moon. Now the ages derived from meteorite samples have been used to study the collisional history of main belt asteroids. In particular, howardite and eucrite meteorites, which are common species found on Earth, have been used to study asteroid Vesta, their parent body. With the aid of computer simulations, researchers determined that meteorites from Vesta recorded high-speed impacts which are now long gone.

Researchers have linked these two datasets and found that the same population of projectiles responsible for making craters and basins on the moon were also hitting Vesta at very high velocities, enough to leave behind a number of telltale, impact-related ages.

The team's interpretation of the howardites and eucrites was augmented by recent close-in observations of Vesta's surface by NASA's Dawn spacecraft. In addition, the team used the latest dynamical models of early main belt evolution to discover the likely source of these high velocity impactors. The team determined that the population of projectiles that hit Vesta had orbits that also enabled some objects to strike the moon at high speeds.

"It appears that the asteroidal meteorites show signs of the asteroid belt losing a lot of mass four billion years ago, with the escaped mass beating up on both the surviving main belt asteroids and the moon at high speeds" says lead author Simone Marchi, who has a joint appointment between two of NASA's Lunar Science Institutes, one at the Southwest Research Institute in Boulder, Colorado, and another at the Lunar and Planetary Institute in Houston. "Our research not only supports the current theory, but it takes it to the next level of understanding."

Image credit: NASA/GSFC/ASU/JPL-Caltech/UCLA/MPS/DLR/IDA

Space Oddity

A revised version of David Bowie's Space Oddity, recorded by Commander Chris Hadfield on board the International Space Station.

Video credit: Guitar and Vocals: Chris Hadfield; Video produced by Evan Hadfield and edited by Andrew Tidby; Music produced and mixed by Joe Corcoran with piano arrangement by Emm Gryner. Special thanks to David Bowie, NASA, ROSCOSMOS and the CSA.

Circular CME

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.

Video credit: Solar Dynamics Observatory/NASA

HR 8799 Planetary System

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.

Image credit: Courtesy of Project 1640

Note: For more information, see Sifting Through the Atmospheres of Far-off Worlds.

Debris Disk Around a White Dwarf Star

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.

Illustration credit: NASA, ESA, STScI, and G. Bacon (STScI)

Note: For more information, see Hubble Finds Dead Stars "Polluted" with Planetary Debris.

GRB 130427A

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.

Image credit: NASA/DOE/Fermi LAT Collaboration

Note: For more information, see NASA's Fermi, Swift See 'Shockingly Bright' Burst.

Hot Gas Falling Into Sagittarius A*

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.

Illustration credit: ESA/C. Carreau

Note: For more information, see:
* Milky Way Black Hole Snacks on Hot Gas
* Galactic Centre
* Herschel Reveals the Milky Way's Warm Heart

Vega VV02, Ready for Liftoff

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.

Photo credit: ESA–S. Corvaja, 2013