Galaxy Group HCG 87

Galaxy Group HCG 87



Posing fo this cosmic family photo are the galaxies of HCG Hickson Compact Group)87, about four hundred millionlight-years distant toward the amphibious constellatio Capricornus.The large edge-onspiral near picture center, the fuzzyelliptical galaxy immediately to its right, and thespiral near the top of the image are identified members of thegroup, while the small spira galaxy in the middle is likely amore distant background galaxy.In any event, a careful examination of the deep image reveals othergalaxies which certainly lie far beyon HCG 87.While not exactly locked i agroup hug, the HCG 87 galaxiesare interactinggravitationally, influencing theirfellow group members' structure and evolution This new imageis from an instrument undergoing commissioningon th Gemini Observatory'sSouth Telescope at Cerro Pachon, Chile.It compares favorably with views of this photogenic galaxy grouprecorded by th HubbleSpace Telescope.

Frosty Mountains on Mars

Frosty Mountains on Mars



What causes the unusual white color on some Martian mountains? The answer can be guessed by noticing that the bright areas disappear as springtime takes hold in the south of Mars: dry ice. Dry carbon dioxide ice sublimates directly to gas from its frozen state. The frosty mountains, named Charitum Montes, have been covered with carbon dioxide ice over the Martian winter. The serene scene pictured above is not a photograph, but rather a computationally constructed digital illusion resulting from the fusion of two color images from the Mars Orbital Camera and topographic data from the Mars Orbiter Laser Altimeter. Both instruments operate from the Mars Global Surveyor robot spacecraft currently orbiting Mars. The red planet continues to grow larger in terrestrial skies as Earth and Mars move closer to their recent-record closest approach on August 27.

Orange Sun Simmering

Orange Sun Simmering



Even a quiet Sun is a busy place. The above image, taken in a single color of light called Hydrogen Alpha, records a great amount of detail of the simmering surface of our parent star. The gradual darkening towards the Sun's edge, called limb darkening, is caused by increased absorption of relatively cool solar gas. Further over the edge, a giant prominence is visible, while a different prominence can be seen in silhouette as the dark streak near the image center. Two active areas of the Sun are marked by bright plages. The above amateur photograph of the Sun was taken just last month through a small telescope and a standard digital camera. In contrast, there are times when our Sun appears much more active.

Launch of the Spirit Rover Toward Mars

Launch of the Spirit Rover Toward Mars



Next stop: Mars. Last month the first of two missions to Mars was launched from Cape Canaveral, Florida, USA above a Boeing Delta II rocket.Pictured above, solid fuel boosters are seen falling away as light from residual exhaust is reflected by the soaring rocket.The Mars Exploration Rover dubbed Spirit is expected to arrive at the red planet this coming January. Upon arriving, parachutes will deploy to slow the spacecraft and surrounding airbags will inflate. The balloon-like package will then bounce around the surface a dozen times or more before coming to a stop. The airbags will then deflate, the spacecraft will right itself, and the Spirit rover will prepare to roll onto Mars. The robotic Spirit is expected to cover as much as 40 meters per day, much more than Sojourner, its 1997 predecessor. Spirit will search for evidence of ancient Martian water, from which implications might be drawn about the possibility of ancient Martian life.A second rover named Opportunity was successfully launched on July 7 and will arrive at Mars a few weeks later.

The Aquarius Dwarf

The Aquarius Dwarf



Our Milky Way Galaxy is not alone. It is part of a gathering of about 50 galaxies known as the Local Group. Members include the Great Andromeda Galaxy (M31), M32, M33, the Large Magellanic Cloud, the Small Magellanic Cloud, Dwingeloo 1, several small irregular galaxies, and many dwarf elliptical an dwarf spheroidal galaxies. Pictured above is the Aquarius Dwarf, a faint dwarf irregular galaxy over 3 million light years away. An earlier APOD erroneously identified the above image as the Sagittarius Dwarf.