Credit:

NASA, ESA, and the Hubble SM4 ERO Team

Explanation:

The bright clusters and nebulae of planet Earth’s night sky are often named for flowers or insects, and NGC 6302 is no exception. With an estimated surface temperature of about 250,000 degrees C, the central star of this particular planetary nebula is exceptionally hot though — shining brightly in ultraviolet light but hidden from direct view by a dense torus of dust. This dramatically detailed close-up of the dying star’s nebula was recorded by the newly upgraded Hubble Space Telescope. Cutting across a bright cavity of ionized gas, the dust torus surrounding the central star is near the center of this view, almost edge-on to the line-of-sight. Molecular hydrogen has been detected in the hot star’s dusty cosmic shroud. NGC 6302 lies about 4,000 light-years away in the arachnologically correct constellation Scorpius.

Credit & Copyright:

Adam Block, Mt. Lemmon SkyCenter, U. Arizona

Explanation:

Unspeakable beauty and unimaginable bedlam can be found together in the Trifid Nebula. Also known as M20, this photogenic nebula is visible with good binoculars towards the constellation of Sagittarius. The energetic processes of star formation create not only the colors but the chaos. The red-glowing gas results from high-energy starlight striking interstellar hydrogen gas. The dark dust filaments that lace M20 were created in the atmospheres of cool giant stars and in the debris from supernovae explosions. Which bright young stars light up the blue reflection nebula is still being investigated. The light from M20 we see today left perhaps 3,000 years ago, although the exact distance remains unknown. Light takes about 50 years to cross M20.

Credit:

X-ray (NASA/CXC/CfA/E.O’Sullivan); Optical (Canada-France-Hawaii-Telescope/Coelum)

Description:

This beautiful image gives a new look at Stephan’s Quintet, a compact group of galaxies discovered about 130 years ago and located about 280 million light years from Earth. The curved, light blue ridge running down the center of the image shows X-ray data from the Chandra X-ray Observatory. Four of the galaxies in the group are visible in the optical image (yellow, red, white and blue) from the Canada-France-Hawaii Telescope. A labeled version identifies these galaxies (NGC 7317, NGC 7318a, NGC 7318b and NGC 7319) as well as a prominent foreground galaxy (NGC 7320) that is not a member of the group. The galaxy NGC 7318b is passing through the core of galaxies at almost 2 million miles per hour, and is thought to be causing the ridge of X-ray emission by generating a shock wave that heats the gas.

Additional heating by supernova explosions and stellar winds has also probably taken place in Stephan’s Quintet. A larger halo of X-ray emission – not shown here – detected by ESA’s XMM-Newton could be evidence of shock-heating by previous collisions between galaxies in this group. Some of the X-ray emission is likely also caused by binary systems containing massive stars that are losing material to neutron stars or black holes.

Stephan’s Quintet provides a rare opportunity to observe a galaxy group in the process of evolving from an X-ray faint system dominated by spiral galaxies to a more developed system dominated by elliptical galaxies and bright X-ray emission. Being able to witness the dramatic effect of collisions in causing this evolution is important for increasing our understanding of the origins of the hot, X-ray bright halos of gas in groups of galaxies.

Stephan’s Quintet shows an additional sign of complex interactions in the past, notably the long tails visible in the optical image. These features were probably caused by one or more passages through the galaxy group by NGC 7317.

Credit & Copyright:

Jason Jennings

Explanation:

Connecting the Pipe Nebula to the colorful region near bright star Antares is a dark cloud dubbed the Dark River, flowing from the picture’s left edge. Murky looking, the Dark River’s appearance is caused by dust obscuring background starlight, although the dark nebula contains mostly hydrogen and molecular gas. Surrounded by dust, Antares, a red supergiant star, creates an unusual bright yellowish reflection nebula. Above it, bright blue double star Rho Ophiuchi is embedded in one of the more typical bluish reflection nebulae, while red emission nebulae are also scattered around the region. Globular star cluster M4 is just seen above and right of Antares, though it lies far behind the colorful clouds, at a distance of some 7,000 light-years. The Dark River itself is about 500 light years away. The colorful skyscape is a mosaic of telescopic images spanning nearly 10 degrees (20 Full Moons) across the sky in the constellation Scorpius.

Credit:

Optical: ESO/E. Helder; X-ray: NASA/CXC/Univ. of Utrecht/J.Vink et al.

Description:

Using Chandra, growing supermassive black holes have been discovered in a sample of blobs, immense reservoirs of hydrogen gas located in the early Universe.These black holes and bursts of star formation are believed to be illuminating and heating the gas in the blobs. This represents a “coming of age” for the galaxies and black holes as they start to switch off their rapid growth.
This image of data from NASA’s Chandra X-ray Observatory and the European Southern Observatory’s Very Large Telescope shows a part of the roughly circular supernova remnant known as RCW 86. This remnant is the remains of an exploded star, which may have been observed on Earth in 185 AD by Chinese astronomers. By studying this remnant, a team of astronomers was able to understand new details about the role of supernova remnants as the Milky Way’s super-efficient particle accelerators. The team shows that the shock wave visible in this area is very efficient at accelerating particles and the energy used in this process matches the number of cosmic rays observed on Earth.

The VLT data (colored red in the composite) was used to measure the temperature of the gas right behind the shock wave created by the stellar explosion. Using X-ray images from Chandra (blue), taken three years apart, the researchers were also able to determine the speed of the shock wave to be between one and three percent of the speed of light. The temperature found by these latest results is much lower than expected, given the measured shock wave’s velocity. The researchers conclude that the missing energy goes into accelerating the cosmic rays.

Description:

NASA’s MESSENGER spacecraft captured this image on January 14, 2008, during its closest approach to Mercury. The image reveals a variety of intriguing surface features, including craters as small as 300 yards across. The image also shows landscapes near Mercury’s equator on the side of the planet never before imaged by spacecraft. These highly detailed close-ups enable planetary geologists to study the processes that have shaped Mercury’s surface over the past 4 billion years. One of the highest and longest scarps cliffs yet seen on Mercury curves from the top center down across the right side of this image. Great forces in Mercury’s crust have thrust the terrain occupying the left two-thirds of the picture up and over the terrain to the right. An impact crater has subsequently destroyed a small part of the scarp near the top of the image. This image was taken from a distance of 3,600 miles from surface of the planet and shows a region approximately 100 miles across.

Credit:

NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington

Credit:

Andrew Fruchter (STScI) et al., WFPC2, HST, NASA

Explanation:

In 1787, astronomer William Herschel discovered the Eskimo Nebula. From the ground, NGC 2392 resembles a person’s head surrounded by a parka hood. In 2000, the Hubble Space Telescope imaged the Eskimo Nebula. From space, the nebula displays gas clouds so complex they are not fully understood. The Eskimo Nebula is clearly a planetary nebula, and the gas seen above composed the outer layers of a Sun-like star only 10,000 years ago. The inner filaments visible above are being ejected by strong wind of particles from the central star. The outer disk contains unusual light-year long orange filaments. The Eskimo Nebula spans about 1/3 of a light year and lies in our Milky Way Galaxy, about 3,000 light years distant, toward the constellation of the Twins (Gemini).

Credit:

ESO,L. Calçada, Alan Stern

Description:

We passed the milestone of being one-third of the distance to Pluto last year, but today — March 19, 2009 — after 38 months and almost 2 billion kilometers of flight, New Horizons has completed precisely one-third of the days in its journey to Pluto. That’s quite a milestone, and we on the mission team celebrate the closing of this chapter of our historic journey across the great expanse of our planetary system, and the opening of mid-cruise, as I described in my January posting

But you won’t have to wait another three years for our next significant distance and flight-time milestones — they come next year, when we cross the halfway point! But whenever quoting such milestones, I have to be careful about the meaning. So when will our spacecraft be halfway to Pluto? Well, that depends on which halfway you mean. (No, I am not kidding.)

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Description:

During the STS-119 mission’s first spacewalk, astronauts Richard Arnold and Steve Swanson (out of frame) connected bolts to permanently attach the S6 truss segment to S5. The spacewalkers plugged in power and data connectors to the truss, prepared a radiator to cool it, opened boxes containing the new solar arrays and deployed the Beta Gimbal Assemblies, containing masts that support the solar arrays.

Image Credit:

NASA

Credit:

NASA/JPL/University of Arizona

Description:

Mars’ seasonal cap of carbon dioxide ice (dry ice) has eroded many beautiful terrains as it sublimates (goes directly from ice to vapor) every spring. In this region we see troughs that form a starburst pattern.

In other areas these radial troughs have been referred to as “spiders,” simply because of their shape. In this region the pattern looks more dendritic as channels branch out numerous times as they get further from the center. The troughs are believed to be formed by gas flowing beneath the seasonal ice to openings where the gas escapes, carrying along dust from the surface below. The dust falls to the surface of the ice in fan-shaped deposits.