What are those planes doing?.......


Edit to fix page distortion-Dot

Astronomy Picture of the Day
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2006 July 22


Mira: The Wonderful Star
Credit: X-ray Image: M. Karovska (Harvard-Smithsonian CfA) et al., CXC / NASA
Illustration: M.Weiss(CXC)
Explanation: To seventeenth century astronomers, Omicron Ceti or Mira was known as a wonderful star - a star whose brightness could change dramatically in the course of about 11 months. Modern astronomers now recognize an entire class of long period Mira-type variables as cool, pulsating, red giant stars, 700 or so times the diameter of the Sun. Only 420 light-years away, red giant Mira (Mira A, right) itself co-orbits with a companion star, a small white dwarf (Mira . Mira B is surrounded by a disk of material drawn from the pulsating giant and in such a double star system, the white dwarf star's hot accretion disk is expected to produce some x-rays. But this sharp, false-color image from the Chandra Observatory also captures the cool giant star strongly flaring at x-ray energies, clearly separated from the x-ray emission of its companion's accretion disk. Placing your cursor over the Chandra x-ray image of Mira will reveal an artist's vision of this still wonderful interacting binary star system.

THE IMAGE IS BETTER IN THE LINK:
http://antwrp.gsfc.nasa.gov/apod/

Credit: M. Romaniello (ESO) et al., ESA, NASA -

Explanation: A mere 168,000 light-years distant, this large, lovely cluster of stars, NGC 1850, is located near the outskirts of the central bar structure in our neighboring galaxy, the Large Magellanic Cloud. A first glance at this Hubble Space Telescope composite image suggests that this cluster's size and shape are reminiscent of the ancient globular star clusters which roam our own Milky Way Galaxy's halo. But NGC 1850's stars are young ... making it a type of star cluster with no known counterpart in the Milky Way. NGC 1850 is also a double star cluster, with a second, compact cluster of stars visible here below and to the right of the large cluster's central region. Stars in the large cluster are estimated to be 50 million years young, while stars in the compact cluster are younger still, with an age of about 4 million years. In fact, the smaller cluster contains T-Tauri stars, thought to be low mass, solar-type stars still in the process of formation. The glowing nebula at the left, like the supernova remnants in our own galaxy, testifies to violent stellar explosions, indicating short-lived massive stars were also present in NGC 1850. Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (USRA) NASA Technical Rep.: Jay Norris. Specific rights apply. A service of: LHEA at NASA/ GSFC & Michigan Tech. U.

Astronomy Picture of the Day
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2006 July 23


The Belt of Venus over the Valley of the Moon
Credit & Copyright: Christine Churchill
Explanation: Although you've surely seen it, you might not have noticed it. During a cloudless twilight, just before sunrise or after sunset, part of the atmosphere above the horizon appears slightly off-color, slightly pink. Called the Belt of Venus, this off-color band between the dark eclipsed sky and the blue sky can be seen in nearly every direction including that opposite the Sun. Straight above, blue sky is normal sunlight reflecting off the atmosphere. In the Belt of Venus, however, the atmosphere reflects light from the setting (or rising) Sun which appears more red. The Belt of Venus can be seen from any location with a clear horizon. Pictured above, the Belt of Venus was photographed above morning fog in the Valley of the Moon, a famous wine-producing region in northern California, USA. The belt is frequently caught by accident in other photographs.

Astronomy Picture of the Day
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2006 July 25


Jupiter's Two Largest Storms Nearly Collide
Credit & Copyright: Travis Rector (U. Alaska), Chad Trujillo (Caltech) et al., Gemini Obs., AURA, NSF
Explanation: Two storms systems larger than Earth are nearly colliding right now on planet Jupiter. No one was sure what would happen, but so far both storms have survived. In the above false-color infrared image taken last week by the Gemini Observatory in Hawaii, the red spots appear white because their cloud tops tower above other clouds. Blue color represents lower clouds than white, while clouds colored red are the deepest. The smaller red spot, sometimes called Red Spot Jr. or just Oval BA, turned red earlier this year for reasons unknown. If both Jovian hurricanes continue to survive, they will surely pass near each other again in a few years since they revolve around Jupiter at different rates. Astronomers will continue to monitor Red Spot Jr. closely, however, to see if it will remain red when it rotates away from the larger Great Red Spot.

Credit: NASA

NGC 604 is an H II region inside the Triangulum Galaxy. It was discovered by William Herschel on September 11, 1784. It is one of the largest H II regions in the Local Group of galaxies; at the galaxy's estimated distance of 2.4 million light-years its longest diameter is roughly 700 light-years (200 + parsecs), over 20 times the size of the visible portion of the Orion Nebula. Over 6300 times more luminous than the Orion Nebula, if it were at the same distance it would outshine Venus. Like all emission nebulae, its gas is ionized by a cluster of massive stars at its center

Astronomy Picture of the Day
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2006 July 27


NGC 7331 and Beyond
Credit & Copyright: R. Jay GaBany (Cosmotography.com)
Explanation: Spiral galaxy NGC 7331 is often touted as an analog to our own Milky Way. About 50 million light-years distant in the northern constellation Pegasus, NGC 7331 was recognized early on as a spiral nebula and is actually one of the brighter galaxies not included in Charles Messier's famous 18th century catalog. Since the galaxy's disk is inclined to our line-of-sight, deep telescopic exposures often result in an image that evokes a strong sense of depth. The effect is further enhanced in this well-framed view by the galaxies that lie beyond this beautiful island universe. The background galaxies are about one tenth the apparent size of NGC 7331 and so lie roughly ten times farther away.

Credit: Apollo 9, NASA


One hundred seventy-three years ago on February 8th, Jules Verne was born in Nantes, France. Inspired by a lifelong fascination with machines, Verne wrote visionary works about "Extraordinary Voyages" including such terrestrial travels as Around the World in 80 Days, Journey to the Centre of the Earth, and Twenty Thousand Leagues Under the Sea. In 1865 he published the story of three adventurers who undertook a journey From the Earth to the Moon. Verne's characters rode a "projectile-vehicle" fired from a huge cannon constructed in Florida, USA. Does that sound vaguely familiar? A century later, the Saturn V rocket and NASA's Apollo program finally turned this work of fiction into fact, propelling adventuresome trios on what was perhaps Verne's most extraordinary voyage. This stirring floodlit view shows the Apollo 9 space-vehicle atop its Saturn V. Launched from a spaceport in Florida in 1969, the Apollo 9 crew were the first to test all lunar landing hardware in space.

Astronomy Picture of the Day
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2006 August 23


Sandy Gas Jets Hypothesized on Mars
Illustration Credit & Copyright: Ron Miller (ASU)
Explanation: What's causing seasonal dark spots on Mars? Every spring, strange dark spots appear near the Martian poles, and then vanish a few months later. These spots typically span 50 meters across and appear fan shaped. Recent observations made with THEMIS instrument onboard NASA's Mars Odyssey, currently orbiting Mars, found the spots to be as cold as the carbon dioxide (CO2) ice beneath them. Based on this evidence, a new hypothesis has been suggested where the spots are caused by explosive jets of sand-laden CO2. As a pole warms up in the spring, frozen CO2 on the surface thins, perforates, and begins to vent gaseous CO2 held underneath. Within this hypothesis, interspersed dark sand would explain the color of the spots, while the underlying frozen CO2 would explain the coolness of the spots. Pictured above, an artist depicts what it might be like to stand on Mars and witness the venting of these tremendous gas and dust jets.

Credit: Hubble, NASA.

Streaming out from the center of the galaxy M87 like a cosmic searchlight is one of nature's most amazing phenomena, a black-hole-powered jet of electrons and other sub-atomic particles traveling at nearly the speed of light. In this Hubble telescope image, the blue jet contrasts with the yellow glow from the combined light of billions of unseen stars and the yellow, point-like clusters of stars that make up this galaxy. Lying at the center of M87, the monstrous black hole has swallowed up matter equal to 2 billion times our Sun's mass. M87 is 50 million light-years from Earth.

Astronomy Picture of the Day
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2006 August 24


The Matter of the Bullet Cluster
Composite Credit: X-ray: NASA/CXC/CfA/ M.Markevitch et al.;
Lensing Map: NASA/STScI; ESO WFI; Magellan/U.Arizona/ D.Clowe et al.
Optical: NASA/STScI; Magellan/U.Arizona/D.Clowe et al.;
Explanation: The matter in galaxy cluster 1E 0657-56, fondly known as the "bullet cluster", is shown in this composite image. A mere 3.4 billion light-years away, the bullet cluster's individual galaxies are seen in the optical image data, but their total mass adds up to far less than the mass of the cluster's two clouds of hot x-ray emitting gas shown in red. Representing even more mass than the optical galaxies and x-ray gas combined, the blue hues show the distribution of dark matter in the cluster. Otherwise invisible to telescopic views, the dark matter was mapped by observations of gravitational lensing of background galaxies. In a text book example of a shock front, the bullet-shaped cloud of gas at the right was distorted during the titanic collision between two galaxy clusters that created the larger bullet cluster itself. But the dark matter present has not interacted with the cluster gas except by gravity. The clear separation of dark matter and gas clouds is considered direct evidence that dark matter exists.

Meteor through M45!

CREDIT: 2005, 2006, Dick Locke. All Rights Reserved.

"The Pleiades" is Messier object 45, and is also known as "The Seven Sisters." It is an open star cluster and features a nice blue reflection nebula. As it resembles a small dipper, it is often mistaken for the Little Dipper. (The real Little Dipper is much larger and always directly North.) Generally there are only 6 stars clearly visible in this object, and there's been discussion as to why there are seven sisters instead of six. This object is quite high in the sky and well-placed for viewing in the Fall. More info about The Pleiades is at SEDS. Quoting SEDS: Their Japanese name is "Subaru", which was taken to christen the car of same name. The Persian name is "Soraya", after which the former Iranian empress was named. Old European (e.g., English and German) names indicate they were once compared to a "Hen with Chicks".

Astronomy Picture of the Day
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2006 August 25


Blue Lagoon
Credit & Copyright: Russell Croman
Explanation: Stars come and go as you slide your cursor over this engaging image of M8, aka the Lagoon Nebula. Of course, the nebula is itself a star-forming region, but the stars that appear and disappear here include background and foreground stars that by chance lie along the same line of sight. In this "for fun" comparison of two nearly identical digital images, the stellar point sources were removed from one image by computer processing to leave only the diffuse emission from the glowing gas clouds. In both pictures, red emission (H-alpha emission) from atomic hydrogen dominates the cosmic lagoon's visible light, but narrow band filters were used to record the image data and map the hydrogen emission to green hues, with emission from sulfur atoms in red and oxygen in blue. The lovely Lagoon Nebula spans about 30 light-years at an estimated distance of 5,000 light-years toward the constellation Sagittarius.

Astronomy Picture of the Day
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2006 August 28


Eight Planets and New Solar System Designations
Credit: International Astronomical Union
Explanation: How many planets are in the Solar System? This popular question now has a new formal answer according the International Astronomical Union (IAU): eight. Last week, the IAU voted on a new definition for planet and Pluto did not make the cut. Rather, Pluto was re-classified as a dwarf planet and is considered as a prototype for a new category of trans-Neptunian objects. The eight planets now recognized by the IAU are: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune. Solar System objects now classified as dwarf planets are: Ceres, Pluto, and the currently unnamed 2003 UB313. Planets, by the new IAU definition, must be in orbit around the sun, be nearly spherical, and must have cleared the neighborhood around their orbits. The demotion of Pluto to dwarf planet status is a source of continuing dissent and controversy in the astronomical community.

Credit: NASA

The Rosette Nebula from the DSS-I.

Astronomy Picture of the Day
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2006 August 29


Supernova Remnant E0102 from Hubble
Credit: Hubble Heritage Team, ESA, NASA
Explanation: It's the blue wisp near the bottom that's the remnant of a tremendous recent supernova explosion. The large pink structure looming to the upper right is part of N76, a large star forming region in our neighboring Small Magellanic Cloud (SMC) galaxy. The supernova remnant wisp, with full coordinate name 1E0102.2-7219 and frequently abbreviated as E0102, also lies in the SMC, about 50 light years away from N76. The above image is a composite of several images taken by the Hubble Space Telescope. E0102 is of research interest because we see it as it appeared only 2,000 years after its explosion. Examination of E0102 therefore gives clues about how an enigmatic supernova works and what materials it dispersed into the surrounding interstellar medium.

Astronomy Picture of the Day
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2006 August 30


A Backward Sunspot and the New Solar Cycle
Credit: MDI, SOHO, ESA, NASA
Explanation: Why is sunspot 905 backwards? Perhaps it is a key marker for the beginning of a new magnetic cycle on our Sun. Every 11 years, our Sun goes through a magnetic cycle, at the end of which its overall magnetic orientation is reversed. An 11-year solar cycle has been observed for hundreds of years by noting peaks and valleys in the average number of sunspots. Just now, the Sun is near Solar Minimum, and likely to start a long progression toward the most active time, called Solar Maximum, in about 5.5 years. An indicator that the sun's magnetic field is reversing is the appearance of sunspots with the reverse magnetic polarity than normal. A few weeks ago, one small candidate reverse sunspot was sighted but faded quickly. Now, however, a larger sunspot with negative polarity is being tracked. This sunspot, numbered 905, appears as the unusual white spot in the above magnetic image of the Sun taken with the SOHO spacecraft a few days ago. In the past few days, Sunspot 905 has actually begun to break apart and might also become the source of coronal mass ejections and explosive solar flares. Solar astronomers predict that the coming Solar Maximum will be unusually active

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2006 August 31


Extra Galaxies
Credit & Copyright: 2006 Astr. Campers, Adam Block (Caelum Obs.), CSS, U. Arizona Alum. Assoc.
Explanation: Careful inspection of the full field of view for this sharp composite image reveals a surprising number of galaxies both near and far toward the constellation Ursa Major. The most striking is clearly NGC 3718, a warped spiral galaxy found near picture center. NGC 3718's faint spiral arms look twisted and extended, its bright central region crossed by obscuring dust lanes. A mere 150 thousand light-years to the right is another large spiral galaxy, NGC 3729. The two are likely interacting gravitationally, accounting for the peculiar appearance of NGC 3718. While this galaxy pair lies about 52 million light-years away, the remarkable Hickson Group 56 can also be seen clustered just below NGC 3718. Hickson Group 56 consists of five interacting galaxies and lies over 400 million light-years away.

This news group is not the place for this kind of post, but I was elevating an injured left foot, and this is the result.


If you think Sne produce excess amounts of very small grain dust, namely hydrocarbons, think again. The progenitor of Sn E0102 was a 20 solar mass Wolf-Rayett star. It may have shed its outer envelope in high stellar winds. When the core blew, the blast obliterated a sizeable bulk of the local stellar dust which it did form, prior to the supernova.

What it left behind was largely ionized elements like O, Ne, Mg, but curiously, little hydrogen. Type Ia supernovae lack H in their spectrum, for instance, but they are when a white dwarf binary explosion takes out the white dwarf (lack of H).

Hydrogen is found in the residual material of Type II Sne, of progenitor stars mostly larger than 5 solar masses. But, how to account for this apparently large 2000 year old remnant leaving little dust, and little hydrogen? Aren't we told that supernovae from massive and supermassive stars produce dust, as well?

The answer might be a Type Ib, which is when a supermassive Wolf-Rayet star, of 20-25 solar masses, sheds material through intense winds, later followed by a collapse and explosion. In the end, little residual hydrogen remains.

Normally, anything that large will also leave a black hole. The Sn E0102 in the SMC, may have shed enough pre-supernova material from its outer envelope to allow a neutron star to remain after the star collapsed.

If you look at the frequencies where neutron stars can be detected (radio and x-ray), E0102 may appear to have a central bright spot, i.e. neutron star. As well, there may be a black hole, which I illustrated in the in Hubble Telescope image. There may be traces remaining from a Sn driven bi-polar jet.



BTW, the HST image from APOD is west-up. I had to change it to north-up for my comparison images. They show the SMC featuring H-alpha, OIII, and SII; the supernova remnant (SNR) in infrared (where the SNR does not show in 3-8 microns, but apparently does at 24 microns as mostly interstellar medium swept up in the explosion); an images in radio, optical, and x-ray.

The optical images show the SNR is oxygen rich, but not H rich. The HST image does include an H-alpha filter, but none shows up in the SNR. H-alpha is found in the outer layer of the nebula, however, as is natural to that region.

The x-ray image largely shows elemental O, Mg, S, at millions of degrees- not dust. The darker blue material is "blue shifted", and the lighter colored material is from a reverse shock (false color is used in radio, IR, and x-ray images). There are two final x-ray images of remnants with neutron stars. No neutron core is so obvious in E0102.

Perhaps E0102 will produce a pulsar, or a black hole. But, where the dust in galaxies comes from, may not be so much supernovae, but the stellar winds preceeding a supernova; as well as planetary nebulae from red giants.



http://s75.photobucket.com/albums/i287/shunastronomy/SMC1/

Wolf-Rayet stars are few and far between. They come and go fairly quickly. Here is one of the 10 or so W-R stars known in the Milky Way. The Magellanic Clouds have an exceptional number. The Small Magellanic has around a dozen.

Tidal shocks have surprising results.

Very interesting post shun I had no idea!

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2006 September 2


Dusty Spiral M66
Credit: M. Neeser (Univ.-Sternwarte Munchen), P. Barthel (Kapteyn Astron. Institute), H. Heyer, H. Boffin (ESO), ESO
Explanation: When morning twilight came to the Paranal Observatory in Chile, astronomers Mark Neeser and Peter Barthel interrupted their search for faint quasars, billions of light-years away. And just for a moment, they used Very Large Telescopes at the European Southern Observatory to appreciate the beauty of the nearby Universe. One result was this stunning view of beautiful spiral galaxy M66, a mere 35 million light-years away. About 100 thousand light-years across with striking dust lanes and bright star clusters along sweeping spiral arms, M66 is well known to astronomers as a member of the Leo Triplet of galaxies. Gravitational interactions with its neighborhood galaxies have likely influenced the shape of dusty spiral M66.

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2006 September 4


The Large Magellanic Cloud in Infrared
Credit: NASA/JPL-Caltech/M. Meixner (STScI) & the SAGE Legacy Team
Explanation: Where does dust collect in galaxies? To help find out, a team of researchers took the most detailed image ever of gas clouds and dust in the neighboring Large Magellanic Cloud (LMC) galaxy. The composite image, shown above, was taken by the Spitzer Space Telescope in infrared light, which highlights the natural glow of the warm materials returned to the interstellar medium by stars. The above mosaic combines 300,000 individual pointings to create a composite 1,000-times sharper than any previous LMC image. Visible are vast clouds of gas and dust, showing in graphic detail that dust prefers regions near young stars (red-tinted bright clouds), scattered unevenly between the stars (green-tinted clouds), and in shells around old stars (small red dots). Also visible are huge caverns cleared away by the energetic outflows of massive former stars. The faint blue (false-color) glow across the bottom is the combined light from the old stars in the central bar of the LMC. The LMC is a satellite galaxy to our own Milky Way Galaxy, spans about 70,000 light years, and lies about 160,000 light years away toward the southern constellation of the Swordfish (Dorado).

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2006 September 8


Messier 110
Credit & Copyright: Johannes Schedler (Panther Observatory)
Explanation: This very sharp telescopic vista features the last object in the modern version of Charles Messier's catalog of bright clusters and nebulae - Messier 110. A dwarf elliptical galaxy, M110 (aka NGC 205) is actually a bright satellite of the large spiral galaxy Andromeda, making M110 a fellow member of the local group of galaxies. Seen through a foreground of nearby stars, M110 is about 15,000 light-years across. That makes it comparable in size to satellite galaxies of our own Milky Way, the Large and Small Magellanic Clouds. Though elliptical galaxies are normally thought to be lacking in gas and dust to form new stars, M110 is known to contain young stars, and faint dust clouds can easily be seen in this detailed image at about the 7 and 11 o'clock positions relative to the galaxy center

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2006 September 14


M33: Spiral Galaxy in Triangulum
Credit & Copyright: Thomas V. Davis (tvdavisastropix.com)
Explanation: The small, northern constellation Triangulum harbors this magnificent face-on spiral galaxy, M33. Its popular names include the Pinwheel Galaxy or just the Triangulum Galaxy. M33 is over 50,000 light-years in diameter, third largest in the Local Group of galaxies after the Andromeda Galaxy (M31), and our own Milky Way. About 3 million light-years from the Milky Way, M33 is itself thought to be a satellite of the Andromeda Galaxy and astronomers in these two galaxies would likely have spectacular views of each other's grand spiral star systems. As for the view from planet Earth, this detailed, wide field image nicely shows off M33's blue star clusters and pinkish star forming regions which trace the galaxy's loosely wound spiral arms. In fact, the cavernous NGC 604 is the brightest star forming region, seen here at about the 1 o'clock position from the galaxy center. Like M31, M33's population of well-measured variable stars have helped make this nearby spiral a cosmic yardstick for establishing the distance scale of the Universe

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2006 September 15


11 Hour Star Trails
Credit & Copyright: Josch Hambsch
Explanation: Fix your camera to a tripod, lock the shutter open, and you can make an image of star trails - graceful concentric arcs traced by the stars as planet Earth rotates on its axis. Of course, the length of the star trails will depend on the exposure time. While exposures lasting just five minutes produce a significant arc, in about 12 hours a given star would trace out half a circle. But in any long exposure, the background glow from light-polluted skies can build up to wash out the trails. Still, astronomer Josch Hambsch produced this stunning composite of star trails around the South Celestial Pole with an effective "all night" exposure time of almost 11 hours. To do it, he combined 128 consecutive five minute long digital exposures recorded in very dark night skies above Namibia. In his final image, the background glow on the right is due in part to the faint, arcing Milky Way.

Astronomy Picture of the Day
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2006 September 18


Eris: The Largest Known Dwarf Planet
Credit & Copyright: W. M. Keck Observatory
Explanation: Is Pluto the largest dwarf planet? No! Currently, the largest known dwarf planet is (136199) Eris, renamed last week from 2003 UB313. Eris is just slightly larger than Pluto, but orbits as far as twice Pluto's distance from the Sun. Eris is shown above in an image taken by a 10-meter Keck Telescope from Hawaii, USA. Like Pluto, Eris has a moon, which has been officially named by the International Astronomical Union as (136199) Eris I (Dysnomia). Dysnomia is visible above just to the right of Eris. Dwarf planets Pluto and Eris are trans-Neptunian objects that orbit in the Kuiper belt of objects past Neptune. Eris was discovered in 2003, and is likely composed of frozen water-ice and methane. Since Pluto's recent demotion by the IAU from planet to dwarf planet status, Pluto has recently also been given a new numeric designation: (134340) Pluto. Currently, the only other officially designated "dwarf planet" is (1) Ceres.

All these are wonderful!

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2006 October 7


COBE All-Sky Map
Credit: COBE Project, DMR, NASA
Explanation: This historic all-sky map is based on the first two years of data from NASA's COsmic Background Explorer (COBE) satellite, launched in November of 1989. The map shows minute temperature variations (red is hotter) imprinted on the Cosmic Microwave Background (CMB) radiation by structures in the early Universe. These detailed measurements of the CMB and other COBE results ushered in an age of precision cosmology, and exactly confirmed the predictions of the Big Bang theory. Playing leading roles in the COBE project, for their resulting discoveries John C. Mather (NASA, Goddard Space Flight Center), and George F. Smoot (UC Berkeley) were selected to receive the 2006 Nobel Prize in Physics.

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2006 October 9


Mars Rover at Victoria Crater Imaged from Orbit
Credit: HiRISE, MRO, LPL (U. Arizona), NASA
Explanation: An unusual spot has been found on Mars that scientists believe is not natural in origin. The spot appears mobile and is now hypothesized to be a robot created by an intelligent species alien to Mars. In fact, the spot appears to be NASA's robotic Opportunity rover currently rolling across Mars. The ability to see the Martian rover from orbit has recently been demonstrated by the High Resolution Imaging Science Experiment on NASA's Mars Reconnaissance Orbiter (MRO). The new spacecraft achieved orbit around Mars in 2006 March. Last week, MRO imaged the location of Victoria Crater and the rover Opportunity that had just arrived there. In the above image at spectacularly high resolution, objects about one meter in size are resolved, and this includes the rolling rover. Such images may help scientists better determine if any safe path exists for Opportunity to enter large crater. In the inset image on the upper left, the whole of Victoria Crater was also imaged by MRO.

These are some amazing pictures, thanks everyone and keep`m comming.

EDIT: Image resized at request of poster - Waspie_Dwarf

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2006 October 11


Markarian's Chain of Galaxies
Credit & Copyright: The Palomar-Quest Survey Team, CalTech
Explanation: Across the heart of the Virgo Cluster of Galaxies lies a striking string of galaxies known as Markarian's Chain. The chain, pictured above, is highlighted on the lower right with two large but featureless lenticular galaxies, M84 and M86, and connects through several large spiral to the upper left, including M88. The home Virgo Cluster is the nearest cluster of galaxies, contains over 2,000 galaxies, and has a noticeable gravitational pull on the galaxies of the Local Group of Galaxies surrounding our Milky Way Galaxy. The center of the Virgo Cluster is located about 70 million light years away toward the constellation of Virgo. At least seven galaxies in the chain appear to move coherently, although others appear to be superposed by chance. The above image is just a small part of a mosaic dubbed the Big Picture taken by the Samuel Oschin Telescope at Palomar Observatory, in California, USA. A mural of the Big Picture will be displayed at the newly renovated Griffith Observatory near Los Angeles, California.

Astronomy Picture of the Day
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2006 December 8


NGC 2174: Emission Nebula in Orion
Credit & Copyright: Dan Kowall (Photonhunter.com)
Explanation: A lesser known sight in the nebula-rich constellation Orion, NGC 2174 can be found with binoculars near the head of the celestial hunter. About 6,400 light-years distant, the glowing cosmic cloud surrounds loose clusters of young stars. Covering an area larger than the full Moon on the sky, this stunning narrow band image adopts a typical color mapping of the atomic emission from NGC 2174. The false-color mapping shows otherwise red hydrogen emission in green hues and emphasizes sulfur emission in red and oxygen in blue. Placing your cursor on the image will reveal an alternative image of the nebula made through broad band filters. The broad band image combines filters in a closer analogy to human vision, dominated by the red glow of hydrogen.
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Many enjoyed this thread, so if it's alright with the Mods, I'm going to start this up again.

Astronomy Picture of the Day
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2006 December 9


Three Planets in Dawn Skies
Credit & Copyright: Tunc Tezel
Explanation: Three children of the Sun rise in the east in this peaceful dawn skyview recorded December 7th near Bolu, Turkey. Inner planet Mercury, fresh from its second transit of the 21st century, stands highest in the bright sky at the top right. Gas giant Jupiter lies below the cloud bank near picture center. A newsworthy Mars is also visible, right of Jupiter and just above the dark cloud bank. On Sunday, these planets will form a much tighter grouping before sunrise, while in the coming days the western sky after sunset will be ruled by brilliant planet Venus, also known as the evening star.
EDIT: VIEW FULL SIZE IMAGE

Astronomy Picture of the Day
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2006 December 10
http://antwrp.gsfc.nasa.gov/apod/image/061...an_apollo17.jpg
CLICK LINK TO SEE IMAGE.

Apollo 17 Panorama: Astronaut Running
Credit: Apollo 17 Crew, NASA; Mosaic Assembled & Copyright: M. Constantine (moonpans.com)
Explanation: What would it be like to explore the surface of another world? In 1972 during the Apollo 17 mission, astronaut Harrison Schmitt found out first hand. In this case, the world was Earth's own Moon. In this recently compiled panorama of lunar photographs originally taken by astronaut Eugene Cernan, the magnificent desolation of the barren Moon is apparent. Visible above and by scrolling right are lunar rocks in the foreground, lunar mountains in the background, some small craters, a lunar rover, and astronaut Schmidt on his way back to the rover. A few days after this image was taken, humanity left the Moon and has yet to return.

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2006 December 12


Light Deposits Indicate Water Flowing on Mars
Credit: Mars Global Surveyor
Explanation: What's creating light-toned deposits on Mars? Quite possibly -- water! Images of the same parts of mid-latitude Mars taken over the years but released only last week have shown unexpected new light-toned deposits where there were none before. One clear case is shown above, where the same crater on Mars is shown as photographed in 1999 August and again in 2005 September. The unusual deposit is visible only on the more recent photograph. Apparent tributaries near the bottom bolster the leading hypothesis that water gushed out of the crater wall, flowed down the crater, and soon evaporated into the thin Martian atmosphere. Although frozen water-ice has been known near the Martian poles for years, free flowing surface water like this was not expected to be seen in the mid-latitudes of Mars. If confirmed, such water springs might make more of Mars hospitable to life and human visitation than previously believed.

SOURCE

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2006 December 13

http://antwrp.gsfc.nasa.gov/apod/image/061...ami_nso_big.gif
Click Link for GIF image

A Large Tsunami Shock Wave on the Sun
Credit: NSO/AURA/NSF and USAF Research Laboratory
Explanation: Tsunamis this large don't happen on Earth. One week ago, a large solar flare from an Earth-sized sunspot produced a tsunami-type shock wave that was spectacular even for the Sun. Pictured above, the tsunami wave was captured moving out from active region AR 10930 by the Optical Solar Patrol Network (OSPAN) telescope in New Mexico, USA. The resulting shock wave, known technically as a Moreton wave, compressed and heated up gasses including hydrogen in the photosphere of the Sun, causing a momentarily brighter glow. The above image was taken in a very specific red color emitted exclusively by hydrogen gas. The rampaging tsunami took out some active filaments on the Sun, although many re-established themselves later. The solar tsunami spread at nearly one million kilometers per hour, and circled the entire Sun in a matter of minutes.

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2006 December 14


Mountains of Titan
Credit: VIMS Team, U. Arizona, ESA, NASA
Explanation: Peering through the thick, hazy atmosphere of Saturn's largest moon, an infrared camera onboard the Cassini spacecraft recorded this view of the tallest mountains ever seen on Titan. Captured during a flyby in late October, the high resolution, false-color mosaic shows a mountain range about 150 kilometers long and about 1.5 kilometers high - likened to the Sierra Nevada mountain range of the western United States, planet Earth. Along Titan's mountain ridges lie bright deposits, thought to be methane snow or other organic material. The icy mountains of Titan were probably formed like Earth's mid-ocean ridges, from material welling up to fill gaps created as surface tectonic plates spread apart.

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2006 December 15


NGC 1055 and M77
Credit & Copyright: Robert Gendler
Explanation: Large spiral galaxy NGC 1055 (top left) joins spiral M77 in this lovely cosmic view toward the constellation Cetus. The narrowed, dusty appearance of edge-on spiral NGC 1055 contrasts nicely with the face-on view of M77's bright nucleus and spiral arms. Both over 100,000 light-years across, the pair are dominant members of a small galaxy group about 60 million light-years away. At that estimated distance, M77 is one of the most remote objects in Charles Messier's catalog and is separated from fellow island universe NGC 1055 by at least 500,000 light-years. The mosaicked field is about the size of the full Moon on the sky and includes colorful foreground Milky Way stars (with diffraction spikes) along with more distant background galaxies.

The new Chandra observations include estimates of the total energy content of the Universe. As shown in this illustration, dark energy is estimated to contribute about 75% of the energy in the Universe, dark matter about 21% and normal matter about 4%. Only the normal matter can be directly detected with telescopes, and about 85% of this is hot, intergalactic gas, as detected in Chandra observations of galaxy clusters.

(Credit: NASA/CXC/M.Weiss)

Astronomy Picture of the Day
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2006 December 17


A Force from Empty Space: The Casimir Effect
Credit & Copyright: Umar Mohideen (U. California at Riverside)
Explanation: This tiny ball provides evidence that the universe will expand forever. Measuring slightly over one tenth of a millimeter, the ball moves toward a smooth plate in response to energy fluctuations in the vacuum of empty space. The attraction is known as the Casimir Effect, named for its discoverer, who, 50 years ago, was trying to understand why fluids like mayonnaise move so slowly. Today, evidence is accumulating that most of the energy density in the universe is in an unknown form dubbed dark energy. The form and genesis of dark energy is almost completely unknown, but postulated as related to vacuum fluctuations similar to the Casimir Effect but generated somehow by space itself. This vast and mysterious dark energy appears to gravitationally repel all matter and hence will likely cause the universe to expand forever. Understanding vacuum fluctuations is on the forefront of research not only to better understand our universe but also for stopping micro-mechanical machine parts from sticking together.

NASA Remote Controlled Large Aircraft 20 Years Ago

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2006 December 18


Aurora Over Iowa
Credit & Copyright: Stan Richards (NightSkyEvents.com)
Explanation: Last Thursday evening, stars were not the only lights in Iowa skies. Spectacular northern lights also shone from the heavens, extending across the midwestern USA and other locations not often graced with auroral displays. The wide-ranging auroral activity was triggered as a large solar flare - an energetic cloud of particles blasted outward from the Sun a few days earlier - collided with planet Earth's magnetosphere. Alerted to conditions ripe for aurora, photographer Stan Richard recorded this apparition over Saylorville Lake, near Des Moines, Iowa, USA. While the colorful rays seem to end just above the water, they are actually at altitudes of 100 kilometers or more.


Tomorrow's picture: massive stars

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2006 December 19


Massive Stars in Open Cluster Pismis 24
Credit: NASA, ESA and J. M. Apellániz (IAA, Spain).
Explanation: How massive can a normal star be? Estimates made from distance, brightness and standard solar models had given one star in the open cluster Pismis 24 over 200 times the mass of our Sun, making it a record holder. This star is the brightest object located just to the right of the gas front in the above image. Close inspection of images taken recently with the Hubble Space Telescope, however, have shown that Pismis 24-1 derives its brilliant luminosity not from a single star but from three at least. Component stars would still remain near 100 solar masses, making them among the more massive stars currently on record. Toward the image left, stars are still forming in the associated emission nebula NGC 6357, including several that appear to be breaking out and illuminating a spectacular cocoon.