It's Full of Stars

First Image Ever Obtained from Mercury Orbit

At 5:20 am EDT on Mar. 29, 2011, MESSENGER captured this historic image of Mercury. This image is the first ever obtained from a spacecraft in orbit about the Solar System’s innermost planet. Over the subsequent six hours, MESSENGER acquired an additional 363 images before downlinking some of the data to Earth. The MESSENGER team is currently looking over the newly returned data, which are still continuing to come down.

Source: NASA.

APOD - Valles Marineris: The Grand Canyon of Mars

Credit: Viking Project, USGS, NASA

Explanation: The largest canyon in the Solar System cuts a wide swath across the face of Mars. Named Valles Marineris, the grand valley extends over 3,000 kilometers long, spans as much as 600 kilometers across, and delves as much as 8 kilometers deep. By comparison, the Earth’s Grand Canyon in Arizona, USA is 800 kilometers long, 30 kilometers across, and 1.8 kilometers deep. The origin of the Valles Marineris remains unknown, although a leading hypothesis holds that it started as a crack billions of years ago as the planet cooled. Several geologic processes have been identified in the canyon. The above mosaic was created from over 100 images of Mars taken by Viking Orbiters in the 1970s.

APOD: MWC 922 - The Red Square Nebula

Credit & Copyright: Peter Tuthill (Sydney U.) & James Lloyd (Cornell)

Explanation: What could cause a nebula to appear square? No one is quite sure. The hot star system known as MWC 922, however, appears to be embedded in a nebula with just such a shape. The above image combines infrared exposures from the Hale Telescope on Mt. Palomar in California, and the Keck-2 Telescope on Mauna Kea in Hawaii. A leading progenitor hypothesis for the square nebula is that the central star or stars somehow expelled cones of gas during a late developmental stage. For MWC 922, these cones happen to incorporate nearly right angles and be visible from the sides. Supporting evidence for the cone hypothesis includes radial spokes in the image that might run along the cone walls. Researchers speculate that the cones viewed from another angle would appear similar to the gigantic rings of supernova 1987A, possibly indicating that a star in MWC 922 might one day itself explode in a similar supernova.

APOD: Mercury and Jupiter at Sunset

Image Credit & Copyright: Göran Strand

Explanation: When warm sunset hues begin to fade, two celestial beacons now shine in the evening twilight, Mercury and Jupiter. Wandering away from the Sun in planet Earth’s sky, Mercury will offer good views this month as spring approaches in the northern hemisphere where the ecliptic plane makes a steep angle with the western horizon. But Jupiter will continue sinking lower in the sky after sunset. In fact, the normally elusive Mercury shines well above Jupiter and the orange sunset glow in this serene sky. Captured earlier this week from the island of of Frösön in northern Sweden, the scene looks across Lake Storsjön toward the village of Hallen and distant mountains. Of course, even better views of Mercury can be had by the MESSENGER spacecraft, now orbiting the Solar System’s innermost planet!

APOD: Saturn’s Serpent Storm

Image Credit & Copyright: Brian Combs

Explanation: Late last year, a new, remarkably bright storm erupted in Saturn’s northern hemisphere. Nicknamed “the Serpent Storm”, the northern hemisphere disturbance is still going strong and now circles far around the planet. Offering spectacular space-based views to the Saturn-orbiting Cassini spacecraft, the storm shows enough contrast with the banded cloud tops to be visible with even modest ground-based equipment, as seen in this sharp image from Buena Vista, Georgia, USA, planet Earth. Amateur astronomers first spotted the bright storm in early December 2010, with the ringed gas giant rising in predawn skies, and continue to monitor the storm’s progress.

APOD: Sideways Galaxy NGC 3628

Image Credit & Copyright: Ken Crawford (Rancho Del Sol Obs.)

Explanation: Dark dust lanes cut across the middle of this gorgeous island universe, a strong hint that NGC 3628 is a spiral galaxy seen sideways. About 35 million light-years away in the northern springtime constellation Leo, NGC 3628 bears the distinction of being the only member of the well known Leo triplet of galaxies not in Charles Messier’s famous catalog. Otherwise similar in size to our Milky Way Galaxy, the disk of NGC 3628 is clearly seen to fan out near the edges. A faint arm of material extends to the upper left. The distorted shape and faint tidal tail suggest that NGC 3628 is interacting gravitationally with the other spiral galaxies in the Leo triplet, M66 and M65. The dusty disk of NGC 3628 is also dotted with the telltale reddish hues of star-forming regions in this sharp telescopic view. Explore the full resolution version here.

APOD: AE Aurigae and the Flaming Star Nebula

Image Credit & Copyright: Rolf Geissinger

Explanation: AE Aurigae is the bright star below and left of center in this evocative portrait of IC 405, also known as the Flaming Star Nebula. Embedded in the cosmic cloud, the hot, variable O-type star energizes the glow of hydrogen along convoluted filaments of atomic gas, its blue starlight scattered by interstellar dust. But AE Aurigae wasn’t formed in the nebula it illuminates. Retracing the star’s motion through space, astronomers conclude that AE Aurigae was probably born in the Orion Nebula. Close gravitational encounters with other stars ejected it from the region, along with another O star, Mu Columbae, over two million years ago. The runaway stars have drifted in opposite directions ever since, separating at about 200 kilometers per second. This sharp, detailed image of IC 405 spans over 5 light-years at the nebula’s estimated distance of 1,500 light-years in the northern constellation Auriga, the Charioteer.

APOD: Discovery in Twilight

Image Credit & Copyright: Tamas Ladanyi (TWAN)

Explanation: As evening twilight faded on March 7, sky gazers around planet Earth enjoyed a beautiful pairing of young crescent Moon and brilliant planet Jupiter. Along with stars setting in the west, the two bright celestial beacons, Moon above and Jupiter below, leave short trails in this well-planned time exposure, a composite of 54 individual frames each 4 seconds long. On its final flight, the Space Shuttle Discovery and International Space Station form the second close pairing in the night skyscape. Still glinting in the sunlight in low Earth orbit, they gracefully trace overlapping arcs from lower right to upper left. Moon, Jupiter, Discovery, and ISS are reflected in the calm waters of Lake Bakonybél, Hungary. Want to see the sequence of frames as a short youtube video? Check it out here. In the video, the trails of the ISS and Discovery are seen to separate as the pair passes above the Moon.

APOD: The International Space Station Expands Again

Credit: STS-133 Shuttle Crew, NASA

Explanation: The developing International Space Station (ISS) has changed its appearance again. In a recently completed rendezvous, the Space Shuttle orbiter Discovery, in its final flight, visited the ISS and added components that included the Leonardo Multi Purpose Logistics Module. The ISS and many of its modules and expansive solar panels are visible in the above picture taken by the Discovery Crew after leaving the ISS to return to Earth. The world’s foremost space outpost can be seen developing over the past several years by comparing the above image to other past images. Also visible above are many different types of modules and supply ships. Construction began on the ISS in 1998.

This is how astronauts keep their hair trimmed at the ISS.

Photo by Italian astronaut Paolo Nespoli.

APOD: Titan, Rings, and Saturn from Cassini

Credit: Cassini Imaging Team, ISS, JPL, ESA, NASA

Explanation: How thin are the rings of Saturn? Brightness measurements from different angles have shown Saturn’s rings to be about one kilometer thick, making them many times thinner, in relative proportion, than a razor blade. This thinness sometimes appears in dramatic fashion during an image taken nearly along the ring plane. The robot Cassini spacecraft now orbiting Saturn has now captured another shot that dramatically highlights the ring’s thinness. The above image was taken in mid January in infrared and polarized light. Titan looms just over the thin rings, while dark ring shadows on Saturn show the Sun to be above the ring plane. Close inspection of the image will show the smaller moon Enceladus on the far right. Cassini, humanity’s first mission to orbit Saturn, currently has operations planned until 2017.

Guarapiranga Dam in São Paulo, Brazil, as seen from the ISS.

Source: astronaut Paolo Nespoli.

A Thin Blue Line

A docked Russian Soyuz spacecraft (right) backdropped by the thin line of Earth’s atmosphere and the blackness of space is featured in this image, which was taken by the STS-133 crew. The image also features a portion of the International Space Station’s Quest airlock and solar array panels.

Source: NASA.

Lisbon, Portugal, as seen from the ISS by astronaut Paolo Nespoli.

A Good Day for a Spacewalk

Emerging from the Quest airlock on the International Space Station, astronaut Alvin Drew began his shared spacewalking duties with fellow astronaut Steve Bowen. Drew and Bowen completed the STS-133 mission’s first spacewalk on Monday, Feb. 28. Drew is the 200th human to perform a spacewalk, his first. This is Steve Bowen’s sixth spacewalk. This is the 154th spacewalk supporting assembly and maintenance of the space station and the 234th excursion conducted by U.S. astronauts.

Source: NASA.