Astronomy Picture

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Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.
2009 August 30

D. rad Bacteria: Candidate Astronauts
Credit: Michael Daly (Uniformed Services University of the Health Sciences), DOE Explanation: These bacteria could survive on another planet. In an Earth lab, Deinococcus radiodurans (D. rad) survive extreme levels of radiation, extreme temperatures, dehydration, and exposure to genotoxic chemicals. Amazingly, they even have the ability to repair their own DNA, usually with 48 hours. Known as an extremophile, bacteria such as D. rad are of interest to NASA partly because they might be adaptable to help human astronauts survive on other worlds. A recent map of D. rad's DNA might allow biologists to augment their survival skills with the ability to produce medicine, clean water, and oxygen. Already they have been genetically engineered to help clean up spills of toxic mercury. Likely one of the oldest surviving life forms, D. rad was discovered by accident in the 1950s when scientists investigating food preservation techniques could not easily kill it. Pictured above, Deinococcus radiodurans grow quietly in a dish.



Tomorrow's picture: blue hot stars

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Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.
2009 August 31

Open Cluster M25
Credit & Copyright: Jean-Charles Cuillandre (CFHT) & Giovanni Anselmi (Coelum Astronomia), Hawaiian Starlight Explanation: Many stars like our Sun were formed in open clusters. The above pictured open cluster, M25, contains thousands of stars and is about two thousand light years distant. The stars in this cluster all formed together about 90 million years ago. The bright young stars in M25 appear blue. Open clusters, also called galactic clusters, contain fewer and younger stars than globular clusters. Also unlike globular clusters, open clusters are generally confined to the plane of our Galaxy. M25 is visible with binoculars towards the constellation of the Archer ( Sagittarius).



Tomorrow's picture: shadow saturn

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Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.
2009 September 1

Shadows of Saturn at Equinox
Credit: Cassini Imaging Team, ISS, JPL, ESA, NASA Explanation: Unusual shadows and dark rings appeared around Saturn near its equinox last month. At that time -- early August -- Saturn's ring plane pointed directly at the Sun. Visible above, Saturn's moon Tethys casts a shadow visible only on the far right. Saturn's own shadow blacks out a large swath of rings on the right. The night side of Saturn glows with ringshine -- sunlight reflected by ring particles back onto Saturn. Images near equinox at Saturn are giving astronomers a chance to search for unexpected shadows that may illuminate previously unknown features of Saturn's complex ring system. Cassini, the robotic spacecraft orbiting Saturn that took this image, is not expected to survive to the next Saturnian equinox in 15 years.



Tomorrow's picture: farther along

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Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.
2009 September 2

Discovery's Rainbow
Credit: NASA, Ben Cooper (Launch Photography) Explanation: Just one minute before midnight EDT, Friday, August 28, the Space Shuttle Discovery began a long arc into a cloudy sky. Following the launch, a bright and remarkably colorful trail was captured in this time exposure from the Banana River Viewing Site, looking east toward pad 39A at the Kennedy Space Center. On STS-128, Discovery docked with the International Space Station Sunday evening. The 13-day mission will exchange space station crew members and deliver more than 7 tons of supplies and equipment. Of course, the equipment includes the Combined Operational Load Bearing External Resistance Treadmill (COLBERT).


Tomorrow's picture: Despina

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Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.
2009 September 3

Despina, Moon of Neptune
Credit: NASA, JPL, Ted Stryk Explanation: Despina is a tiny moon of Neptune. A mere 148 kilometers across, diminutive Despina was discovered in 1989, in images from the Voyager 2 spacecraft taken during its encounter with the solar system's most distant gas giant planet. But looking through the Voyager 2 data 20 years later, amateur image processor (and philosophy professor) Ted Stryk discovered something no one had recognized before -- images that show the shadow of Despina in transit across Neptune's blue cloud tops. His composite view of Despina and its shadow is composed of four archival frames taken on August 24, 1989, separated by nine minutes. Despina itself has been artificially brightened to make it easier to see. In ancient Greek mythology, Despina is a daughter of Poseidon (the Roman god Neptune).


Tomorrow's picture: edged out

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Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.
2009 September 4

6 Years of Saturn
Credit & Copyright: Alan Friedman Explanation: Today, planet Earth passes through the plane of Saturn's rings. From the perspective of earthbound astronomers, Saturn's rings will be edge-on. The problem is, Saturn itself is now very close to the Sun, low on horizon after sunset, so good telescopic images will be difficult to come by. Still, this composite of Saturn views taken from 2004 - 2009 (lower right to upper left) illustrates the change in ring tilt over the last six years and includes a nearly edge-on ring view, based on images captured earlier this year. While Saturn's south pole is clearly seen in the sequence, particularly at the lower right, it will be hidden in the coming years. Saturn's north pole will be increasingly visible, along with the tilting rings, as the planet emerges this fall in the predawn sky.


Tomorrow's picture: big Q

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Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.
2009 September 5

Supernova Remnant E0102-72
Credit: X-ray - NASA / CXC / MIT / D.Dewey et al., NASA / CXC / SAO / J.DePasquale;
Optical - NASA / STScI Explanation: The expanding debris cloud from the explosion of a massive star is captured in this multiwavelength composite, combining x-ray and optical images from the Chandra and Hubble telescopes. Identified as E0102-72, the supernova remnant lies about 190,000 light-years away in our neighboring galaxy, the Small Magellanic Cloud. A strong cosmic source of x-rays, E0102 was imaged by the Chandra X-ray Observatory shortly after its launch in 1999. In celebration of Chandra's 10th anniversary, this colorful view of E0102 and its environs was created, including additional Chandra data. An analysis of all the data indicates that the overall shape of E0102 is most likely a cylinder that is viewed end-on rather than a spherical bubble. The intriguing result implies that the massive star's explosion has produced a shape similar to what is seen in some planetary nebulae associated with lower mass stars. At the distance of the Small Magellanic Cloud, this field of view spans about 150 light-years.


Tomorrow's picture: speeders all

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Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.
2009 September 6

CMBR Dipole: Speeding Through the Universe
Credit: DMR, COBE, NASA, Four-Year Sky Map Explanation: Our Earth is not at rest. The Earth moves around the Sun. The Sun orbits the center of the Milky Way Galaxy. The Milky Way Galaxy orbits in the Local Group of Galaxies. The Local Group falls toward the Virgo Cluster of Galaxies. But these speeds are less than the speed that all of these objects together move relative to the cosmic microwave background radiation (CMBR). In the above all-sky map from the COBE satellite, radiation in the Earth's direction of motion appears blueshifted and hence hotter, while radiation on the opposite side of the sky is redshifted and colder. The map indicates that the Local Group moves at about 600 kilometers per second relative to this primordial radiation. This high speed was initially unexpected and its magnitude is still unexplained. Why are we moving so fast? What is out there?



Tomorrow's picture: club Jupiter

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Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.
2009 September 7

Jupiter Over the Mediterranean
Credit & Copyright: Tunç Tezel (TWAN) Explanation: This vacation included a sight to remember. Pictured above, a picturesque starscape capped a serene seascape as seen from Turkey this past August. In the above digitally stitched panorama, the Gelidonya Lighthouse shines in the foreground before a calm Mediterranean Sea. On the left, Jupiter is the brightest point in the image and since on the same side of the Sun as the Earth, was near its yearly brightest. Glowing just shy of magnitude -3, Jupiter was brighter than any star in the sky, and brighter even than Mars was during its famously bright opposition of 2003 August. On the right, the band of the Milky Way Galaxy fades into distant atmospheric haze above the Jupiter is nearing the closest part of its elliptical orbit to the Sun and so will appear even brighter during its next opposition in 2010 September.



Tomorrow's picture: Jupiter dark

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Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.
2009 September 8

Unexpected Impact on Jupiter
Credit: ALPO, Theo Ramakers Explanation: Two months ago, something unexpected hit Jupiter. First discovered by an amateur astronomer Anthony Wesley on 2009 July 19, the impact was quickly confirmed and even imaged by the Hubble Space Telescope the very next day. Many of the world's telescopes then zoomed in on our Solar System's largest planet to see the result. Some of these images have been complied into the above animation. Over the course of the last month and a half, the above time-lapse sequence shows the dark spot -- first created when Jupiter was struck -- deforming and dissipating as Jupiter's clouds churned and Jupiter rotated. It is now thought that a small comet -- perhaps less than one kilometer across -- impacted Jupiter on or before 2009 July 19. Although initially expected to be visible for only a week, astronomers continue to track atmospheric remnants of the impact for new information about winds and currents in Jupiter's thick atmosphere.



Tomorrow's picture: oregon trails