#2006 mar

2006 March 11

Colors of Comet Pojmanski

Credit & Copyright: Adam Block (Caelum Observatory), R. Jay GaBany (Cosmotography.com)

Explanation: Comet Pojmanski flew by planet Earth last weekend on a surprise trip through the inner solar system. Then an easy binocular target for morning skygazers, Pojmanski ultimately showed off a long tail, but it also presented some lovely green-blue hues as gas molecules in its tenuous coma and tail fluoresced in the sunlight. Astronomers Adam Block and Jay GaBany recorded this colorful high-resolution view on March 3rd in the darkness just before twilight. The picture spans about one full moon on the sky. Comet Pojmanski (C/2006 A1) is outward bound and fading now, still visible in binoculars for northern hemisphere observers.

Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (USRA)

NASA Official: Jay Norris.

A service of: EUD at NASA / GSFC

2006 March 26

Doomed Star Eta Carinae

Credit: J. Morse (Arizona State U.), K. Davidson (U. Minnesota) et al., WFPC2, HST, NASA

Explanation: Eta Carinae may be about to explode. But no one knows when - it may be next year, it may be one million years from now. Eta Carinae's mass - about 100 times greater than our Sun - makes it an excellent candidate for a full blown supernova. Historical records do show that about 150 years ago Eta Carinae underwent an unusual outburst that made it one of the brightest stars in the southern sky. Eta Carinae, in the Keyhole Nebula, is the only star currently thought to emit natural LASER light. This image, taken in 1996, resulted from sophisticated image-processing procedures designed to bring out new details in the unusual nebula that surrounds this rogue star. Now clearly visible are two distinct lobes, a hot central region, and strange radial streaks. The lobes are filled with lanes of gas and dust which absorb the blue and ultraviolet light emitted near the center. The streaks remain unexplained. Will these clues tell us how the nebula was formed? Will they better indicate when Eta Carinae will explode?

Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (USRA)

NASA Official: Jay Norris.

A service of: EUD at NASA / GSFC

2006 March 25

Northern Spring on Mars

Credit: MSSS, JPL, NASA

Explanation: Astronomical spring came to planet Earth's northern hemisphere this week (and autumn to the south) with the equinox on March 20th. But on Mars, northern spring began on January 22nd. Still in northern springtime, the Red Planet currently has a similar appearance to this composite of images from previous years taken by the long-lasting Mars Global Surveyor spacecraft. The sprawling dark region near picture center is Syrtis Major, with the whitish Hellas impact basin just below, in the southern hemisphere. The four seasons on Earth each last about 90 earth days, while Mars' larger and more eccentric elliptical orbit results in seasons that are longer and vary more widely in length - from about 140 to 190 martian sols.

Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (USRA)

NASA Official: Jay Norris.

A service of: EUD at NASA / GSFC

2006 March 21

The Coma Cluster of Galaxies

Credit & Copyright: Jim Misti (Misti Mountain Observatory)

Explanation: Almost every object in the above photograph is a galaxy. The Coma Cluster of Galaxies pictured above is one of the densest clusters known - it contains thousands of galaxies. Each of these galaxies houses billions of stars - just as our own Milky Way Galaxy does. Although nearby when compared to most other clusters, light from the Coma Cluster still takes hundreds of millions of years to reach us. In fact, the Coma Cluster is so big it takes light millions of years just to go from one side to the other! Most galaxies in Coma and other clusters are ellipticals, while most galaxies outside of clusters are spirals. The nature of Coma's X-ray emission is still being investigated.

Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (USRA)

NASA Official: Jay Norris.

A service of: EUD at NASA / GSFC

2006 March 18

Red Spot Jr.

Credit & Copyright: Mike Salway

Explanation: Jupiter's Great Red Spot is a swirling storm seen for over 300 years, since the beginning of telescopic observations of the Solar System's ruling gas giant. But over the last month it has been joined by Red Spot Jr. Thought to be similar to the Great Red Spot itself, this not-so-great red spot was actually seen to form as smaller whitish oval-shaped storms merged and then developed the remarkable reddish hue. This webcam image showing the two red tinted Jovian storms was recorded on the morning of March 12 from the Central Coast of New South Wales, Australia - part of a series showing Jupiter's rotation. Similar in diameter to planet Earth, Red Spot Jr. is expected to last for a while, and trails the Great Red Spot by about an hour as the planet rotates. Astronomers still don't exactly understand why Jupiter's red spots are red.

Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (USRA)

NASA Official: Jay Norris.

A service of: EUD at NASA / GSFC

2006 March 10

Enceladus and the Search for Water

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

Explanation: Based on data from Cassini spacecraft instruments, researchers are now arguing that liquid water reservoirs exist only tens of meters below the surface of Saturn's small (500 kilometer diameter) but active moon Enceladus. The exciting new results center around towering jets and plumes of material erupting from the moon's surface. The plumes originate in the long tiger stripe fractures of the south polar region pictured here. Detailed models suport conclusions that the plumes arise from near-surface pockets of liquid water at temperatures of 273 kelvins (0 degrees Celsius), even though Enceladus has a surface temperature of about 73 kelvins (-200 degrees Celsius). Clearly an important step in the search for water and the potential for the origin of life beyond planet Earth, such near-surface reservoirs of water would be far more accessible than, for example, the internal ocean detected on the Jovian moon Europa.

Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (USRA)

NASA Official: Jay Norris.

A service of: EUD at NASA / GSFC

2006 March 2

Messier 101

Image Credit: NASA, ESA, CFHT, NOAO; Acknowledgement - K.Kuntz (GSFC), F.Bresolin (U.Hawaii), J.Trauger (JPL), J.Mould (NOAO), Y.-H.Chu (U. Illinois)

Explanation: Big, beautiful spiral galaxy M101 is one of the last entries in Charles Messier's famous catalog, but definitely not one of the least. About 170,000 light-years across, this galaxy is enormous, almost twice the size of our own Milky Way galaxy. M101 was also one of the original spiral nebulae observed by Lord Rosse's large 19th century telescope, the Leviathan of Parsontown. Assembled from 51 exposures recorded by the Hubble Space Telescope in the 20th and 21st centuries, with additional data from ground based telescopes, this mosaic of M101 is touted as the largest, most detailed spiral galaxy view ever released from Hubble. The sharp image shows stunning features along the galaxy's face-on disk of stars and dust along with background galaxies, some visible right through M101 itself. Also known as the Pinwheel Galaxy, M101 lies within the boundaries of the northern constellation Ursa Major, about 25 million light-years away.

Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (USRA)

NASA Official: Jay Norris.

A service of: EUD at NASA / GSFC

2006 March 17

The Big Dipper Cluster

Credit & Copyright: Noel Carboni

Explanation: A well-known asterism in northern skies, The Big Dipper is easy to recognize even when viewed upside down. Part of the larger constellation of Ursa Major, the bright dipper stars above are named (left to right along the dipper) Dubhe, Merak, Phecda, Megrez, Alioth, Mizar/Alcor, and Alkaid. Of course, stars in any given constellation are unlikely to be physically related. But surprisingly, most of the big dipper stars do seem to be headed in the same direction as they plough through space, a property they share with other stars spread out over an even larger area across the sky. Their measured common motion suggests that they all belong to a loose, nearby star cluster, thought to be on average only about 75 light-years away and up to 30 light-years across. The cluster is more properly known as the Ursa Major Moving Group.

Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (USRA)

NASA Official: Jay Norris.

A service of: EUD at NASA / GSFC