科普 神奇的宇宙----图片(每天更新中)

wsbswdx

CMBR Dipole: Speeding Through the Universe

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?

wsbswdx

M104 Hubble Remix

Explanation: The striking spiral galaxy M104 is famous for its nearly edge-on profile featuring a broad ring of obscuring dust. Seen in silhouette against a bright bulge of stars, the swath of cosmic dust lanes lends a hat-like appearance to the galaxy in optical images suggesting the more popular moniker, The Sombrero Galaxy. Here, Hubble Space Telescope archival image data has been reprocessed to create this alternative look at the well-known galaxy. The newly developed processing improves the visibility of details otherwise lost in overwhelming glare, in this case allowing features of the galaxy's dust lanes to be followed well into the bright central region. About 50,000 light-years across and 28 million light-years away, M104 is one of the largest galaxies at the southern edge of the Virgo Galaxy Cluster.

wsbswdx

Comet over California

Explanation: Still gracing northern skies, a fading Comet Holmes lies at the top edge of this colorful skyview, recorded on March 4. The reddish emission nebula below it is NGC 1499, also known as the California Nebula for its resemblance to the outline of the state on the US west coast. Of course, the two cosmic clouds by chance lie along nearly the same line-of-sight and so only appear to be close together and of similar size. The California Nebula is actually about 100 light-years long and 1,500 light-years away, drifting through the Orion Arm of our spiral Milky Way Galaxy. Comet Holmes is about 20 light-seconds in diameter, sweeping through our solar system a mere 25 light-minutes away, beyond the orbit of Mars. The molecules of the comet's gaseous coma fluoresce in sunlight. The California Nebula's glow is characteristic of hydrogen atoms recombining with long lost electrons, originally stripped away (ionized) by ultraviolet starlight. Providing the energetic starlight is Xi Persei, the prominent star below the nebula.

wsbswdx

Vela Supernova Remnant

Explanation: The plane of our Milky Way Galaxy runs through this complex and beautiful skyscape. At the northwestern edge of the constellation Vela (the Sails) the 16 degree wide, 30 frame mosaic is centered on the glowing filaments of the Vela Supernova Remnant, the expanding debris cloud from the death explosion of a massive star. Light from the supernova explosion that created the Vela remnant reached Earth about 11,000 years ago. In addition to the shocked filaments of glowing gas, the cosmic catastrophe also left behind an incredibly dense, rotating stellar core, the Vela Pulsar. Some 800 light-years distant, the Vela remnant is likely embedded in a larger and older supernova remnant, the Gum Nebula. The broad mosaic includes other identified emission and reflection nebulae, star clusters, and the remarkable Pencil Nebula.

wsbswdx

The International Space Station Expands Again

Explanation: The developing International Space Station (ISS) has changed its appearance again. Last month, the Space Shuttle orbiter Atlantis visited the ISS and added components that included the Columbus Science Laboratory. The entire array of expansive solar panels is visible in this picture taken by the Atlantis 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 past images. Also visible above are many different types of modules, a robotic arm, another impressive set of solar panels, and a supply ship. Construction began on the ISS in 1998.

wsbswdx

NGC 6334: The Cat's Paw Nebula

Explanation: Nebulae are perhaps as famous for being identified with familiar shapes as perhaps cats are for getting into trouble. Still, no known cat could have created the vast Cat's Paw Nebula visible in Scorpius. At 5,500 light years distant, Cat's Paw is an emission nebula with a red color that originates from an abundance of ionized hydrogen atoms. Alternatively known as the Bear Claw Nebula or NGC 6334, stars nearly ten times the mass of our Sun have been born there in only the past few million years. Pictured above, the end of the Cat's Paw nebula was imaged from the Blanco 4-meter Telescope in Chile.

wsbswdx

The LMC Galaxy in Glowing Gas

Explanation: What goes on inside of a galaxy? To help find out, astronomers from the Magellanic Cloud Emission Line Survey team imaged our neighboring LMC galaxy in spectacular detail and highlighted very specific colors of light emitted by glowing gas. The above mosaic of over 1,500 images of the Large Magellanic Cloud (LMC) is the result -- clicking on the image will bring up an image with much greater detail. The colors highlighted on the mosaic are light emitted by hydrogen (red), oxygen (green), and sulfur (yellow), while light from individual stars has been subtracted. The mosaic shows what a busy and violent place the inside of the LMC really is. Visible in the above image are many small planetary nebulas pushed out by low mass stars, large emission nebula of ambient interstellar gas set aglow by massive stars, and huge gaseous supernova remnants cast off by massive stars exploding. The extended connected filaments are mostly connected supernova remnants. The LMC, a familiar sight to an unaided eye in the southern hemisphere, spans about 15,000 light years and lies only about 180,000 light years distant.

wsbswdx

D. rad Bacteria: Candidate Astronauts

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.

wsbswdx

Apollo 12: Self-Portrait

Explanation: In November of 1969, Apollo 12 astronaut-photographer Charles "ete" Conrad recorded this masterpiece while documenting colleague Alan Bean's lunar soil collection activities on the Oceanus Procellarum. The image is dramatic and stark. The harsh environment of the Moon's Ocean of Storms is echoed in Bean's helmet, a perfectly composed reflection of Conrad and the lunar horizon. Is it art? Works of photojournalists originally intent on recording the human condition on planet Earth, such as Lewis W. Hine's images from New York City in the early 20th century, or Margaret Bourke-White's magazine photography are widely regarded as art. Similarly many documentary astronomy and space images can be appreciated for their artistic and esthetic appeal.

wsbswdx

LL Ori and the Orion Nebula

Explanation: This esthetic close-up of cosmic clouds and stellar winds features LL Orionis, interacting with the Orion Nebula flow. Adrift in Orion's stellar nursery and still in its formative years, variable star LL Orionis produces a wind more energetic than the wind from our own middle-aged Sun. As the fast stellar wind runs into slow moving gas a shock front is formed, analogous to the bow wave of a boat moving through water or a plane traveling at supersonic speed. The small, arcing, graceful structure just above and left of center is LL Ori's cosmic bow shock, measuring about half a light-year across. The slower gas is flowing away from the Orion Nebula's hot central star cluster, the Trapezium, located off the upper left corner of the picture. In three dimensions, LL Ori's wrap-around shock front is shaped like a bowl that appears brightest when viewed along the "bottom" edge. The beautiful picture is part of a large mosaic view of the complex stellar nursery in Orion, filled with a myriad of fluid shapes associated with star formation.

wsbswdx

Orion Nebula: The Hubble View

Explanation: Few cosmic vistas excite the imagination like the Orion Nebula. Also known as M42, the nebula's glowing gas surrounds hot young stars at the edge of an immense interstellar molecular cloud only 1,500 light-years away. The Orion Nebula offers one of the best opportunities to study how stars are born partly because it is the nearest large star-forming region, but also because the nebula's energetic stars have blown away obscuring gas and dust clouds that would otherwise block our view - providing an intimate look at a range of ongoing stages of starbirth and evolution. This detailed image of the Orion Nebula is the sharpest ever, constructed using data from the Hubble Space Telescope's Advanced Camera for Surveys and the European Southern Observatory's La Silla 2.2 meter telescope. The mosaic contains a billion pixels at full resolution and reveals about 3,000 stars. In apparent size, the picture is as large as the Full Moon. At the distance of M42 it spans thirteen light-years.

wsbswdx

Cartwheel of Fortune

Explanation: By chance, a collision of two galaxies has created a surprisingly recognizable shape on a cosmic scale - The Cartwheel Galaxy. The Cartwheel is part of a group of galaxies about 400 million light years away in the constellation Sculptor (two smaller galaxies in the group are visible below and left). Its rim is an immense ring-like structure over 100,000 light years in diameter, composed of star forming regions filled with extremely bright, massive stars. When galaxies collide they pass through each other, their individual stars do not come into contact. However, this ring-like shape is the result of gravitational disruption caused by a smaller galaxy passing through a large one, compressing the interstellar gas and dust and causing a star formation wave to move out like a ripple across the surface of a pond. This false-color composite image of the Cartwheel Galaxy is from space-based observatories. The Chandra X-ray Observatory data is in purple, the Galaxy Evolution Explorer ultraviolet view is in blue, the Hubble Space Telescope visible light picture is in green and the Spitzer Space Telescope infrared image is in red.

wsbswdx

A Roll Cloud Over Missouri

Explanation: What kind of cloud is this? A roll cloud. These rare long clouds may form near advancing cold fronts. In particular, a downdraft from an advancing storm front can cause moist warm air to rise, cool below its dew point, and so form a cloud. When this happens uniformly along an extended front, a roll cloud may form. Roll clouds may actually have air circulating along the long horizontal axis of the cloud. A roll cloud is not thought to be able to morph into a tornado. Unlike a similar shelf cloud, a roll cloud is completely detached from their parent cumulonimbus cloud. Pictured above, a roll cloud extends far into the distance in the summer of 2005 above Albany, Missouri, USA.

wsbswdx

Stardust Capsule Returns to Earth

Explanation: A flying saucer from outer space crash-landed in the Utah desert yesterday after being tracked by radar and chased by helicopters and airplanes. Like last time, no space aliens were involved. The saucer, the Stardust return capsule, is carrying bits of Comet Wild 2 captured two years ago during a rendezvous between Stardust and the ancient comet. The capsule is pictured above entering a temporary clean room in Utah before part of it is shipped to NASA's Johnson Space Center in Houston, Texas, USA. In the inset on the lower right, an artist depicts the capsule as it likely looked after it parachuted to a landing in the Utah desert. The upper right insert shows an image of the streaking capsule taken yesterday by a DC-8 chase plane. The bits of Comet Wild 2 stored in the Stardust return capsule are likely older than the Sun and will be inspected over the next few years for clues about the early years of our Solar System. You, too, can help look for dust grains in the Stardust aerogel!

wsbswdx

The Sombrero Galaxy from HST

Explanation: Why does the Sombrero Galaxy look like a hat? Reasons include the Sombrero's unusually large and extended central bulge of stars, and dark prominent dust lanes that appear in a disk that we see nearly edge-on. Billions of old stars cause the diffuse glow of the extended central bulge. Close inspection of the bulge in the above photograph shows many points of light that are actually globular clusters. M104's spectacular dust rings harbor many younger and brighter stars, and show intricate details astronomers don't yet fully understand. The very center of the Sombrero glows across the electromagnetic spectrum, and is thought to house a large black hole. Fifty million-year-old light from the Sombrero Galaxy can be seen with a small telescope towards the constellation of Virgo.

wsbswdx

Stars of the Galactic Center

Explanation: The center of our Milky Way Galaxy is hidden from the prying eyes of optical telescopes by clouds of obscuring dust and gas. But in this stunning vista, the Spitzer Space Telescope's infrared cameras, penetrate much of the dust revealing the stars of the crowded galactic center region. A mosaic of many smaller snapshots, the detailed, false-color image shows older, cool stars in bluish hues. Reddish glowing dust clouds are associated with young, hot stars in stellar nurseries. The galactic center lies some 26,000 light-years away, toward the constellation Sagittarius. At that distance, this picture spans about 900 light-years.

wsbswdx

Infrared Helix

Explanation: Over six hundred light years from Earth, in the constellation Aquarius, a sun-like star is dying. Its last few thousand years have produced the Helix Nebula (NGC 7293), a well studied and nearby example of a Planetary Nebula, typical of this final phase of stellar evolution. Emission in this infrared Spitzer Space Telescope image of the Helix comes mostly from the nebula's molecular hydrogen gas. The gas appears to be clumpy, forming thousands of comet-shaped knots each spanning about twice the size of our solar system. Bluer, more energetic radiation is seen to come from the heads with redder emission from the tails, suggesting that they are more shielded from the central star's winds and intense ultraviolet radiation. The nebula itself is about 2.5 light-years across. The Sun is expected to go through its own Planetary Nebula phase ... in another 5 billion years.

wsbswdx

The Tadpoles of IC 410

Explanation: This close-up view shows a portion of otherwise faint emission nebula IC 410 in striking false-colors. It also shows two remarkable denizens of the glowing gas cloud at the right - the "tadpoles" of IC 410. The picture is a composite of images taken through narrow band filters intended to trace atoms in the nebula. Emission from sulfur atoms is shown in red, hydrogen atoms in green, and oxygen in blue. Partly obscured by foreground dust, the nebula itself surrounds NGC 1893, a young galactic cluster of stars that energizes the glowing gas. Composed of denser, cooler gas and dust, the tadpoles are around 10 light-years long. Sculpted by wind and radiation from the cluster stars, their tails trail away from the cluster's central region. IC 410 lies some 12,000 light-years away, toward the constellation Auriga. At that distance, this image spans about 70 light-years.

wsbswdx

M45: The Pleiades Star Cluster

Explanation: Perhaps the most famous star cluster on the sky, the Pleiades can be seen without binoculars from even the depths of a light-polluted city. Also known as the Seven Sisters and M45, the Pleiades is one of the brightest and closest open clusters. The Pleiades contains over 3000 stars, is about 400 light years away, and only 13 light years across. Quite evident in the above photograph are the blue reflection nebulae that surround the brighter cluster stars. Low mass, faint, brown dwarfs have also been found in the Pleiades. (Editors' note: The prominent diffraction spikes are caused by the telescope itself and may be either distracting or provide aesthetic enhancement, depending on your point of view.)

wsbswdx

Arp 188 and the Tadpole's Tidal Tail

Explanation: In this stunning vista recorded with the Hubble Space Telescope's Advanced Camera for Surveys, distant galaxies form a dramatic backdrop for disrupted spiral galaxy Arp 188, the Tadpole Galaxy. The cosmic tadpole is a mere 420 million light-years distant toward the northern constellation Draco. Its eye-catching tail is about 280 thousand light-years long and features massive, bright blue star clusters. One story goes that a more compact intruder galaxy crossed in front of Arp 188 - from left to right in this view - and was slung around behind the Tadpole by their gravitational attraction. During the close encounter, tidal forces drew out the spiral galaxy's stars, gas, and dust forming the spectacular tail. The intruder galaxy itself, estimated to lie about 300 thousand light-years behind the Tadpole, can be seen through foreground spiral arms at the upper left. Following its terrestrial namesake, the Tadpole Galaxy will likely lose its tail as it grows older, the tail's star clusters forming smaller satellites of the large spiral galaxy.