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NASA's Hubble Looks for Poss
…
| Title |
NASA's Hubble Looks for Possible Moon Resources |
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NASA's Hubble Looks for Poss
…
| Title |
NASA's Hubble Looks for Possible Moon Resources |
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NASA's Hubble Looks for Poss
…
| Title |
NASA's Hubble Looks for Possible Moon Resources |
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NASA's Hubble Looks for Poss
…
| Title |
NASA's Hubble Looks for Possible Moon Resources |
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NASA's Hubble Looks for Poss
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| Title |
NASA's Hubble Looks for Possible Moon Resources |
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NASA's Hubble Looks for Poss
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| Title |
NASA's Hubble Looks for Possible Moon Resources |
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The Tycho Catalog Skymap
| Title |
The Tycho Catalog Skymap |
| Abstract |
This image set is a skymap of stars from the Tycho and Hipparcos star catalogs. The maps are plotted in Platte-Carre projection (Cylindrical-Equidistant) using celestial coordinates making them suitable for mapping onto spheres in many popular animation programs. The stars are plotted as gaussian point-spread functions (PSF) so the size and amplitude of the stars corresponds to their relative intensity. The stars are also elongated in Right Ascension (celestial longitude) based on declination (celestial latitude) so stars in the polar regions will still be round when projected on a sphere. Stars fainter than the "threshold magnitude", usually selected as 5th magnitude, have their magnitude-intensity curve adjusted so they appear brighter than they really are. This makes the band of the Milky Way more visible. Stellar colors are assigned based on B and V magnitudes (B and V are stellar magnitudes measured through different filters). If Tycho B and V magnitudes are unavailable, Johnson B and V magnitudes are used instead. From these, an effective stellar temperature is derived using the algorithms described in Flower (ApJ 469, 355 1996). Corrections were noted from Siobahn Morgan (UNI). The effective temperature was then converted to CIE tristimulus X,Y,Z triples assuming a blackbody emission distribution. The X,Y,Z values are then converted to red-green-blue color pixels. About 2.4 million stars are plotted, but many may be below the pixel intensity resolution. The three most conspicuously missing objects on these maps are the Andromeda galaxy (M31) and the two Magellanic Clouds. [The images in this visualization were updated August 28, 2007 to fix a bug in the star generation algorithm.] |
| Completed |
2007-08-14 |
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Fires in Turkey's Adana Regi
…
| Title |
Fires in Turkey's Adana Region |
| Description |
Dozens of fires were detected in the Adana region of Turkey on June 15, 2003, by the Moderate Resolution Imaging Spectroradiometer (MODIS) on the Terra satellite. The fires have been marked with red dots in this true-color image. The Adana region is a low-lying coastal area ringed by the Taurus Mountains to the north and the Nur Mountains, covered in green vegetation, to the east. Because this region is one of the most agriculturally productive in the whole country, it is likely these fires are being used in for agricultural activities such as land clearing. At bottom right is Syria. The high-resolution image provided above is 500 meters per pixel. The MODIS Rapid Response System provides this image at MODIS' maximum spatial resolution of 250 meters. Image courtesy Jeff Schmaltz, MODIS Rapid Response Team, NASA GSFC |
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In the Heart of the Crab
| Title |
In the Heart of the Crab |
| Explanation |
The supernova [ http://imagine.gsfc.nasa.gov/docs/science/know_l1/supernovae.html ] explosion that formed the Crab Nebula [ http://www.seds.org/messier/m/m001.html ] was first seen [ http://oposite.stsci.edu/pubinfo/pr/96/22/crabhist.html ] on the year 1054. Last week, astronomers released [ http://heritage.stsci.edu/public/2000june1/crab.html ] a new image of the still-evolving center of the explosion. The above representative-color photograph [ http://heritage.stsci.edu/public/2000june1/displaycrab.html ] was taken in colors emitted by specific elements [ http://chemlab.pc.maricopa.edu/periodic/about.html#history ] including hydrogen [ http://chemlab.pc.maricopa.edu/periodic/h.html ] (orange), nitrogen [ http://pearl1.lanl.gov/periodic/elements/7.html ] (red), sulfur [ http://pearl1.lanl.gov/periodic/elements/16.html ] (pink), and oxygen [ http://pearl1.lanl.gov/periodic/elements/8.html ] (green), with the result appearing oddly similar to a Jackson Pollock [ http://metalab.unc.edu/wm/paint/auth/pollock/ ] painting. Visible is a complex array of gas filaments [ http://antwrp.gsfc.nasa.gov/apod/ap980208.html ] rushing out at over 5 million kilometers per hour. Even at these tremendous speeds, though, it takes a filament over 600 years to cross the 3 light year [ http://www.howstuffworks.com/question94.htm ] wide frame. The rapidly spinning neutron star [ http://www.astro.umd.edu/~miller/nstar.html ] remnant [ http://antwrp.gsfc.nasa.gov/apod/ap981128.html ] of this ancient cataclysm [ http://violet.pha.jhu.edu/~wpb/hstcrab/hstcrab.html ] is visible as the lower of the two bright stars just above the photograph [ http://heritage.stsci.edu/public/2000june1/crabtable.html#facts ] center. The Crab Nebula [ http://antwrp.gsfc.nasa.gov/apod/ap991122.html ] (M1 [ http://antwrp.gsfc.nasa.gov/apod/ap960626.html ]) is located 6,500 light-years away towards the constellation [ http://www.starshine.com/frankn/constell.asp ] of Taurus [ http://www.astronomical.org/constellations/tau.html ]. |
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Apollo 17: VIP Site Anaglyph
| Title |
Apollo 17: VIP Site Anaglyph |
| Explanation |
Get out your red/blue glasses and check out [ http://www.apolloarchive.com/apollo_gallery.html ] this stereo scene from Taurus-Littrow valley on the Moon! The color anaglyph [ http://en.wikipedia.org/wiki/Anaglyph_image ] features a detailed [ http://antwrp.gsfc.nasa.gov/apod/ap040417.html ] 3D view of Apollo 17's Lunar Rover [ http://www.batsinthebelfry.com/rover/index.php ] in the foreground -- behind it lies the Lunar Module and distant lunar hills. Because the world was going to be able to watch [ http://history.nasa.gov/40thann/videos.htm ] the Lunar Module's [ http://antwrp.gsfc.nasa.gov/apod/ap060107.html ] ascent stage liftoff via the rover's TV camera, this parking place [ http://www.boulder.swri.edu/~durda/Apollo/ landing_sites.html ] was also known as the VIP [ http://en.wikipedia.org/wiki/ Very_Important_Person_(person) ] Site. In December [ http://antwrp.gsfc.nasa.gov/apod/ap040605.html ] of 1972, Apollo 17 astronauts Eugene Cernan and Harrison Schmitt spent about 75 hours on the Moon, while colleague Ronald Evans orbited overhead. The crew returned with 110 kilograms of rock and soil [ http://www.nasm.si.edu/exhibitions/cchoice/moonrocks/ moonrocks6.htm ] samples, more than from any of the other lunar landing sites. Cernan and Schmitt are still the last to walk [ http://www.alanbeangallery.com/ ] (or drive) on the Moon [ http://www.hq.nasa.gov/alsj/frame.html ]. |
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GLAST Gamma Ray Sky Simulati
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| Title |
GLAST Gamma Ray Sky Simulation |
| Explanation |
What shines in the gamma-ray sky? This simulated image models the intensities of gamma rays [ http://cossc.gsfc.nasa.gov/epo/nasm/VU/index.html ] with over 40 million times the energy of visible light, and represents how the sky might appear to the Gamma-ray Large Area Space Telescope [ http://glast.gsfc.nasa.gov ] (GLAST) after its first year in orbit. Familiar steady stars are absent from the dramatic 80x80 degree field which looks directly away from the center of the Galaxy. Instead, the Geminga [ http://imagine.gsfc.nasa.gov/docs/science/how_l2/timing.html ] and Crab pulsars [ http://oposite.stsci.edu/pubinfo/pr/96/22.html ] - bizarre, spinning stellar corpses known to be neutron stars [ http://antwrp.gsfc.nasa.gov/apod/ap980425.html ] - are the two brightest gamma-ray sources. These and other gamma-ray bright objects in the field, monstrous active galaxies [ http://imagine.gsfc.nasa.gov/docs/science/know_l2/ active_galaxies.html ] and still unknown [ http://antwrp.gsfc.nasa.gov/apod/ap000324.html ] sources, have been detected by the Energetic Gamma-Ray Experiment Telescope [ http://cossc.gsfc.nasa.gov/cossc/egret/ ] (EGRET) on the orbiting Compton Gamma-Ray Observatory [ http://cossc.gsfc.nasa.gov ]. However, most of the simulated sources are new - extrapolating current ideas and anticipating discoveries resulting from GLAST's improved gamma-ray vision [ http://glast.gsfc.nasa.gov/ Anticen/ ]. The central broad band of faint gamma-ray emission is due to high-energy cosmic rays [ http://antwrp.gsfc.nasa.gov/apod/ap980618.html ] colliding with interstellar gas in the outer spiral arms of the Milky Way [ http://antwrp.gsfc.nasa.gov/apod/ap980523.html ], while below is a diffuse energetic glow from prominent molecular clouds [ http://antwrp.gsfc.nasa.gov/apod/ap970430.html ] in Monoceros, Orion, Auriga, and Taurus. Intended to explore [ http://www-glast.sonoma.edu/ ] extreme environments in the distant cosmos [ http://universe.gsfc.nasa.gov/ ] and planned for launch in 2005, GLAST is under development by NASA, U.S., and international partners. |
|
Composite Crab
| Title |
Composite Crab |
| Explanation |
The Crab Nebula is cataloged as M1, the first object on Charles Messier's [ http://www.seds.org/messier/xtra/history/biograph.html ] famous list of things which are not comets. In fact, the Crab [ http://www.seds.org/messier/more/m001_rosse.html ] is now known to be a supernova remnant [ http://imagine.gsfc.nasa.gov/docs/science/know_l2/ supernova_remnants.html ], expanding debris from the death explosion of a massive star. This intriguing [ http://chandra.harvard.edu/photo/2006/crab/ ] false-color image combines data from space-based observatories, Chandra [ http://chandra.harvard.edu/ ], Hubble [ http://hubblesite.org/ ], and Spitzer [ http://www.spitzer.caltech.edu ], to explore the debris cloud [ http://chandra.harvard.edu/photo/2006/crab/ animations.html ] in x-rays (blue-purple), optical (green), and infrared (red) light. One of the most exotic objects known to modern astronomers, the Crab Pulsar [ http://antwrp.gsfc.nasa.gov/apod/ap050326.html ], a neutron star spinning 30 times a second, is the bright spot near picture center. Like a cosmic dynamo [ http://antwrp.gsfc.nasa.gov/apod/ap990929.html ], this collapsed remnant of the stellar core powers the Crab's emission across the electromagnetic spectrum. Spanning about 12 light-years, the Crab Nebula is 6,500 light-years away in the constellation Taurus [ http://www.allthesky.com/constellations/taurus/ ]. |
|
September Sky
| Title |
September Sky |
| Explanation |
Star clusters, planets, and a red giant posed for this portrait of the night [ http://antwrp.gsfc.nasa.gov/apod/ap000708.html ] sky from rural Jasper County, Iowa, USA. Astrophotographer [ http://geocities.com/stanzman_2001/ ] Stan Richard recorded the four minute time exposure looking east around midnight on September 3rd at Ashton-Wildwood Park. To avoid star trails [ http://pages.prodigy.net/pam.orman/JoeTrails.html ], his camera was mounted on a barndoor-style [ http://casa.colorado.edu/~rachford/widefield/ barndoor.html ] tracker to compensate for the Earth's rotation [ http://antwrp.gsfc.nasa.gov/apod/ap000715.html ]. Can you identify his celestial subjects? (Click on the image for a labeled version.) The Pleiades [ http://www.pantheon.org/mythica/articles/p/ pleiades.html ] and Hyades [ http://www.pantheon.org/mythica/articles/h/hyades.html ], the closest open or galactic star clusters [ http://www.seds.org/messier/open.html ] to the Sun, should be recognizable to beginning stargazers [ http://starchild.gsfc.nasa.gov/ ]. Of course gas giant Jupiter [ http://galileo.jpl.nasa.gov/jupiter/jupiter.html ] rules as the brightest object in the picture and the largest planet in the Solar System, but second largest planet Saturn [ http://www.jpl.nasa.gov/cassini/Kids/stories/ ] is also visible nearby. For sheer size cool red giant star Aldebaran [ http://www.astro.uiuc.edu/~kaler/sow/aldebaran.html ] is more impressive though, spanning about forty times the diameter of the Sun. Sixty light-years away and yellowish in this picture, Aldebaran is known as Alpha Tauri, the brightest star in Taurus [ http://aibn47.astro.uni-bonn.de/~gallery/constellations/ taurus/ ], the Bull. |
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XZ Tauri System Ejects Gas B
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| Title |
XZ Tauri System Ejects Gas Bubble |
| Explanation |
Why is the binary star system XZ Tauri emitting a hot bubble of expanding gas? Although astronomers can only presently speculate, the Hubble Space Telescope [ http://www.stsci.edu/hst/ ] clearly documents this unusual behavior in three dramatic photographs [ http://oposite.stsci.edu/pubinfo/PR/2000/32/pr-photos.html ] over the past five years. Even without knowing why, the recently released [ http://oposite.stsci.edu/pubinfo/PR/2000/32/content/prc0032a.txt ] sequence [ http://oposite.stsci.edu/pubinfo/PR/2000/32/index.html ] shows in unprecedented clarity the beginnings of a cooling zone -- a region where the expanding gas bubble cools off by emitting light as electrons [ http://www-spof.gsfc.nasa.gov/Education/welect.html ] and ions [ http://www-spof.gsfc.nasa.gov/Education/wposion.html ] meet and recombine [ http://www.mpia-hd.mpg.de/THEORY/preprints/kessel/1999/dissertation/node20.html ]. The XZ Tauri [ http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=1999ApJ...515L..35K ] star system is known to reside in the Taurus [ http://www.seds.org/Maps/Stars_en/Fig/taurus.html ] star forming region located about 500 light-years [ http://einstein.stcloudstate.edu/Dome/constellns/lightyear.html ] away. XZ Tau [ http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=1990A%26A...230L...1H ] is composed of two very young stars separated by roughly the same distance as between our Sun and Pluto [ http://www.seds.org/nineplanets/nineplanets/overview.html ]. The bubble has been expanding over the past thirty years and now extends to nearly fifteen times the binary [ http://antwrp.gsfc.nasa.gov/apod/binary_stars.html ] separation. |
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October Skylights
| Title |
October Skylights |
| Explanation |
With brilliant Venus [ http://nssdc.gsfc.nasa.gov/planetary/factsheet/ venusfact.html ] above the western horizon at sunset and Jupiter [ http://galileo.jpl.nasa.gov/ ] and Saturn [ http://www.jpl.nasa.gov/cassini/ ] high in the east by early evening, November's night sky is filled with bright planets. October's sky featured bright planets as well and, triggered by the active Sun, some lovely auroral displays [ http://www.exploratorium.edu/learning_studio/ auroras/ ]. This colorful aurora was recorded by astrophotographer Wade Clark in skies above Hamilton, Washington, USA on the night of October 4th. Through the shimmering northern lights [ http://climate.gi.alaska.edu/Curtis/aurora/ aurora.html ] Jupiter and Saturn are easy to spot [ http://antwrp.gsfc.nasa.gov/apod/ap000929.html ] flanking the V-shaped head of Taurus [ http://server.remc12.k12.mi.us/csplanet/myth/ taurus.html ] the Bull. Of course, just above lies the lovely Pleiades star cluster. Solar activity [ http://spaceweather.com/ ] will also produce auroral shows in November, particularly at high northern and southern latitudes. Plus, November skygazers can certainly anticipate a celestial performance on the evening of the 17th/18th -- the moonlit Leonid meteor shower [ http://spacescience.com/headlines/y2000/ast10oct_1.htm ]. |
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Long Leonid
| Title |
Long Leonid |
| Explanation |
Just last week this long lovely Leonid shower [ http://spacescience.com/headlines/y2000/ ast21nov_1.htm ] meteor arced through the night. Captured on [ http://www.comet-track.com/meteor/leonids00/ leonids00.html ] November 17/18 by photographer [ http://www.comet-track.com ] Bob Yen, the meteor trail spans about 70 times the apparent diameter of the full moon in the skies above Mt. Wilson, California, USA. The Leonid's path flashes from the outskirts of constellation Gemini [ http://www.seds.org/Maps/Stars_en/Fig/ gemini.html ] to the triangle-shaped head of Taurus [ http://www.astro.uiuc.edu/~kaler/sow/ taurus-p.html ] (lower right). Of course, the trail points back toward Leo, the shower's [ http://comets.amsmeteors.org/meteors/showers/ leonids.html ] eponymous radiant, while passing near such night sky notables as galactic star cluster M35 [ http://www.seds.org/messier/m/m035.html ] (upper left) and Taurus's brightest star, red giant Aldebaran [ http://www.astro.uiuc.edu/~kaler/sow/ aldebaran.html ]. Though the sky was ruled by a bright but waning Moon and brilliant Jupiter, the Leonid meteor shower [ http://www.spaceweather.com/meteors/gallery_18nov00.html ] still awed observers at dark sky locations with peak rates of hundreds of meteors per hour. |
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Apollo 17's Moonship
| Title |
Apollo 17's Moonship |
| Explanation |
Awkward and angular looking, Apollo 17's lunar module Challenger [ http://nssdc.gsfc.nasa.gov/cgi-bin/database/www-nmc?72-096C ] was designed for flight [ http://users.specdata.com/home/pullo/lm_mis1.htm ] in the vacuum of space. This sharp picture from the command module America [ http://nssdc.gsfc.nasa.gov/cgi-bin/database/www-nmc?72-096A ], shows Challenger's ascent stage in lunar orbit. Small reaction control thrusters are at the sides of the moonship with the bell of the ascent rocket engine itself underneath. The hatch allowing access to the lunar surface [ http://www.hq.nasa.gov/alsj/a17/a17main.html ] is visible in the front and a round radar antenna appears at the top. This spaceship performed gracefully, landing on the moon and returning the Apollo astronauts to the orbiting command module in December of 1972 - but where is Challenger now? [ http://nssdc.gsfc.nasa.gov/planetary/lunar/apolloloc.html ] Its descent stage remains at the Apollo 17 landing site, Taurus-Littrow [ http://cass.jsc.nasa.gov/pub/expmoon/Apollo17/A17_lsite.html ]. The ascent stage was intentionally crashed nearby after being jettisoned from the command module prior to the astronauts' return [ http://www.hq.nasa.gov/alsj/a17/a17.homeward.html ] to planet Earth. Apollo 17's mission [ http://antwrp.gsfc.nasa.gov/apod/ap970504.html ] was the sixth and last time astronauts have landed on the moon. |
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NGC 1410/1409: Intergalactic
…
| Title |
NGC 1410/1409: Intergalactic Pipeline |
| Explanation |
These two galaxies [ http://oposite.stsci.edu/pubinfo/PR/2001/02/index.html ] are interacting in a surprising way, connected by a "pipeline" of obscuring material that runs between them over 20,000 light-years of intergalactic space. Silhouetted [ http://antwrp.gsfc.nasa.gov/apod/ap000511.html ] by starlight, the dark, dusty ribbon appears to stretch from NGC 1410 (the galaxy at the left) and wrap itself around NGC 1409 (at right). A mere 300 million light-years distant in the constellation of Taurus [ http://aibn47.astro.uni-bonn.de/~gallery/constellations/ taurus/ ], the pair's recent collision has likely drawn out this relatively thin lane of material which is only about 500 light-years wide. Though the Hubble Space Telescope image dramatically illustrates [ http://www.astr.ua.edu/keel/research/ngc1410.html ] how galaxies exchange matter when they collide, it also presents challenges to current pictures of galaxy evolution [ http://oposite.stsci.edu/pubinfo/PR/97/34/ af3.html ]. The titanic collision has [ http://antwrp.gsfc.nasa.gov/apod/ap981219.html ] triggered star formation in NGC 1410 as evidenced by its blue star forming regions, yet NGC 1409 remains devoid of hot, young blue stars [ http://oposite.stsci.edu/pubinfo/PR/97/34/af4.html ] even though observations indicate that material is flowing into it. Bound by gravity, these two [ http://www.astr.ua.edu/white/pairs/individual.html ] galaxies are doomed to future collisions, merging [ http://oposite.stsci.edu/pubinfo/PR/97/34/ index.html#Animations ] over time into one. |
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Stars and the Solstice Sun
| Title |
Stars and the Solstice Sun |
| Explanation |
If you could turn off the atmosphere's [ http://webexhibits.org/causesofcolor/ 14B.html ] ability to scatter overwhelming sunlight, today's daytime sky might look something like this ... with the Sun surrounded by the stars of the constellations Taurus and Gemini. Of course, today is the Solstice [ http://en.wikipedia.org/wiki/Solstice ]. Traveling along the ecliptic plane [ http://www.phy6.org/stargaze/Secliptc.htm ], the Sun is at its northernmost position in planet Earth's sky, marking the astronomical [ http://www.badastronomy.com/bad/misc/ badseasons.html ] beginning of summer [ http://shakespeare.mit.edu/midsummer/ ] in the north. Accurate for the exact time of today's Solstice, this composite image also [ http://www.astropix.com/HTML/SHOWCASE/SOLSTICE.HTM ] shows the Sun at the proper scale (about the angular size [ http://chandra.harvard.edu/photo/scale.html ] of the Full Moon). Open star cluster M35 [ http://antwrp.gsfc.nasa.gov/apod/ap060419.html ] is to the Sun's left, and the other two bright stars in view are Mu and Eta [ http://antwrp.gsfc.nasa.gov/apod/ap040408.html ] Geminorum. Digitally superimposed on a nighttime image of the stars, the Sun itself is a composite of a picture taken through a solar filter and a series of images of the solar corona recorded during the solar eclipse [ http://antwrp.gsfc.nasa.gov/apod/ap980311.html ] of February 26, 1998 by Andreas Gada. |
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Strange Orange Soil on the M
…
| Title |
Strange Orange Soil on the Moon |
| Explanation |
How did orange soil appear on the Moon? This mystery began [ http://antwrp.gsfc.nasa.gov/apod/ap010523.html http://www.hq.nasa.gov/office/pao/History/alsj/a17/a17.sta4.html ] when astronaut Harrison Schmidt [ http://antwrp.gsfc.nasa.gov/apod/ap010523.html http://www.hq.nasa.gov/alsj/a17/a17.crew.html#jackbio ] noticed the off-color patch near Apollo 17 [ http://antwrp.gsfc.nasa.gov/apod/ap001209.html ]'s Taurus-Littrow [ http://cass.jsc.nasa.gov/pub/expmoon/Apollo17/A17_lsite.html ] landing site in 1972. Schmidt and fellow astronaut Eugene Cernan [ http://www.hq.nasa.gov/alsj/a17/a17.crew.html#genebio ] scooped up some of the unusual orange soil [ http://www.hq.nasa.gov/office/pao/History/alsj/a17/a17.sta4.html ] for detailed inspection back on Earth. Pictured above [ http://images.jsc.nasa.gov/images/pao/AS17/10076006.htm ] is a return sample shown greatly magnified, with its discovery location shown in the inset [ http://images.jsc.nasa.gov/images/pao/AS17/10075960.htm ]. The orange soil [ http://www.lpi.usra.edu/expmoon/Apollo17/A17_sampact.html ] contains particles less than 0.1 millimeter across, some of the smallest particles yet found on the Moon [ http://www.nasm.edu/galleries/attm/wl.so.1.html ]. Lunar geologists now think that the orange soil [ http://www.solarviews.com/cap/moon/moondust.htm ] was created during an ancient fire-fountain [ http://www.solarviews.com/cap/volc/fountain.htm ]. Detailed chemical and dating analyses indicate [ http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=1996LPI....27..303D ] that during an explosive volcanic eruption 3.64 billion years ago, small drops [ http://antwrp.gsfc.nasa.gov/apod/ap000322.html ] of molten rock cooled rapidly into the nearly spherical colored grains. The origin of some of the unusual elements found in the soil [ http://curator.jsc.nasa.gov/curator/lunar/lunar.htm ], however, remains unknown. |
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The T Tauri Star Forming Sys
…
| Title |
The T Tauri Star Forming System |
| Explanation |
What did the Sun look like before there were planets? A prototype laboratory for the formation of low mass stars like our Sun is the T Tauri system [ http://etacha.as.arizona.edu/~eem/ttau/ ], one of the brighter star systems toward the constellation [ http://www.physics.csbsju.edu/astro/asp/constellation.faq.html ] of Taurus [ http://www.astronomical.org/constellations/tau.html ]. In young systems [ http://heasarc.gsfc.nasa.gov/docs/rosat/gallery/stars_ttauri.html ], gravity causes a gas cloud [ http://antwrp.gsfc.nasa.gov/apod/ap990511.html ] to condense. The situation then usually becomes quite complex, as some of the infalling gas is heated so much by collisions that it is immediately expelled as an outgoing wind [ http://antwrp.gsfc.nasa.gov/apod/ap000318.html ]. Complex geometries including jets [ http://antwrp.gsfc.nasa.gov/apod/ap991129.html ] and disks [ http://antwrp.gsfc.nasa.gov/apod/ap991219.html ] form as the infalling and outflowing gas collide and interact with a changing magnetic field [ http://antwrp.gsfc.nasa.gov/apod/ap001203.html ]. Pictured above [ http://www.cfht.hawaii.edu/Science/Astros/Imageofweek/ciw290500.html ] is a false-color image of the T Tauri system itself, which turns out to be a binary [ http://antwrp.gsfc.nasa.gov/apod/ap970219.html ]. In a few million years [ http://www.go.ednet.ns.ca/~larry/stars/prtostar.html ], the central condensate will likely become hot enough to ignite nuclear fusion [ http://fusedweb.pppl.gov/ ], by which time much of the surrounding circumstellar material will either have fallen in or have been driven off by the stellar wind [ http://www-istp.gsfc.nasa.gov/Education/wsolwind.html ]. At that time, a new star [ http://antwrp.gsfc.nasa.gov/apod/ap971008.html ] will shine. |
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The Pulsar Powered Crab
| Title |
The Pulsar Powered Crab |
| Explanation |
In the Summer of 1054 [ http://www.chaco.com/park/archaeology/nebula.html ] A.D. Chinese astronomers reported [ http://www.stsci.edu/pubinfo/PR/96/22/crabhist.html ] that a star in the constellation of Taurus [ http://www.astro.wisc.edu/~dolan/constellations/ constellations/Taurus.html ] suddenly became as bright as the full Moon. Fading slowly, it remained visible for over a year. It is now understood that a spectacular supernova explosion [ http://antwrp.gsfc.nasa.gov/apod/ap980217.html ] - the detonation of a massive star whose remains [ http://antwrp.gsfc.nasa.gov/apod/ap980613.html ] are now visible as the Crab Nebula [ http://antwrp.gsfc.nasa.gov/apod/ap010325.html ]- was responsible for the apparition. The core of the star collapsed [ http://www.stsci.edu/pubinfo/PR/96/22/pulsars.html ] to form a rotating neutron star [ http://www.astro.umd.edu/~miller/nstar.html ] or pulsar [ http://pulsar.princeton.edu/rpr.shtml ], one of the most exotic objects known to modern astronomers. Like a cosmic lighthouse, the rotating Crab pulsar generates beams of radio, visible, x-ray and gamma-ray energy [ http://cossc.gsfc.nasa.gov/images/epo/gallery/ pulsars/index.html ] which, as the name suggests, produce pulses as they sweep across our view. Using a stunning series of visible light images [ http://oposite.stsci.edu/pubinfo/PR/96/22.html#Photos ] taken with the Hubble Space Telescope (HST) in 1995, astronomers have discovered spectacular pulsar powered motions within the Crab nebula. Highlights of this HST Crab "movie" [ http://www.stsci.edu/pubinfo/PR/96/22.html#Movies ] show wisps of material moving away from the pulsar at half the speed of light, a scintillating halo, and an intense knot of emission dancing, sprite-like, above the pulsar's pole. Only 10 kilometers wide but more massive than the sun, the pulsar's energy drives the dynamics and emission of the nebula itself which is more than 10 light-years across. |
|
Moonless Perseid Sky
| Title |
Moonless Perseid Sky |
| Explanation |
Last weekend, dark, moonless night skies brought many sightings of Perseid meteors [ http://science.nasa.gov/headlines/y2007/ 11jul_greatperseids.htm ] to skygazers all over [ http://spaceweather.com/meteors/gallery_12aug07.htm ] planet Earth. Early Sunday morning astronomer John Chumack's camera captured this Perseid [ http://meteorshowersonline.com/perseids.html ] meteor streak with a flare near the end of its track over Yellow Springs, Ohio. The single, four minute long exposure looks toward the constellation of Taurus and the eastern horizon. The meteor streak points back to the annual meteor [ http://ssd.jpl.nasa.gov/?meteor_streams ] shower's radiant [ http://antwrp.gsfc.nasa.gov/apod/ap070812.html ] in Perseus off the upper left corner of the picture. Of course [ http://spaceweather.com/meteors/perseids/images2007/ skymap_north.gif ], the view includes the well-known Pleiades [ http://www.astro.uiuc.edu/~kaler/sow/pleiades-p.html ] Star cluster (near top center) with a bright yellowish planet Mars below it. Also seen with a yellowish tint but not quite as bright as Mars, the giant star Aldebaran [ http://www.astro.uiuc.edu/~kaler/sow/aldebaran.html ] anchors the V-shaped Hyades [ http://www.astro.uiuc.edu/~kaler/sow/hyades-p.html ] star cluster left of center, above the trees. |
|
Apollo 17's Lunar Rover
| Title |
Apollo 17's Lunar Rover |
| Explanation |
In December of 1972, Apollo 17 [ http://antwrp.gsfc.nasa.gov/apod/ap001209.html ] astronauts Eugene Cernan and Harrison Schmitt spent about 75 hours exploring [ http://www.hq.nasa.gov/alsj/a17/a17j.html ] the Moon's Taurus-Littrow valley [ http://cass.jsc.nasa.gov/pub/expmoon/Apollo17/A17_lsite.html ] while colleague Ronald Evans orbited overhead. Cernan and Schmitt were the last humans to walk or ride on the Moon - aided in their explorations [ http://antwrp.gsfc.nasa.gov/apod/ap010523.html ] by a Lunar Roving Vehicle [ http://www-sn.jsc.nasa.gov/PlanetaryMissions/EXLibrary/docs/ ApolloCat/Part1/LRV.htm ]. The skeletal-looking lunar rover was [ http://www.hq.nasa.gov/office/pao/History/alsj/ lrvhand.html ] just over 10 feet long, 6 feet wide and easily carried astronauts, equipment, and rock samples in the Moon's [ http://nssdc.gsfc.nasa.gov/planetary/factsheet/moonfact.html ] low gravity (about 1/6 Earth's). In this picture [ http://www.hq.nasa.gov/alsj/a17/images17.html ], Cernan stands at the back of the rover which carried the two astronauts in lawn-chair style seats. An umbrella-shaped high gain antenna and TV camera are mounted in the front. Powered by four 1/4 horsepower electric motors, one for each wheel [ http://antwrp.gsfc.nasa.gov/apod/ap990501.html ], this rover was driven a total of about 18 miles across the lunar surface [ http://www.hq.nasa.gov/alsj/frame.html ]. Its estimated top speed was a blazing 8 miles per hour. |
|
Pioneer 10: The First 7 Bill
…
| Title |
Pioneer 10: The First 7 Billion Miles |
| Explanation |
"Q:" What was made by humans and is 7.3 billion miles away? "A:" Pioneer 10 -- and 1997 was the 25th anniversary [ http://quest.arc.nasa.gov/pioneer10/ ] of its launch. Almost 11 light-hours distant, Pioneer 10 is presently [ http://spaceprojects.arc.nasa.gov/Space_Projects/pioneer/ PNStat.html ] about twice as far from the Sun as Pluto, and bound for interstellar space [ http://spaceprojects.arc.nasa.gov/Space_Projects/pioneer/ path.html ] at 28,000 miles per hour. The distinction of being the first human artifact to venture beyond the known planets [ http://heasarc.gsfc.nasa.gov/docs/cosmic/solar_system.html ] of the Solar System is just one in a long list of firsts for this spacefaring ambassador [ http://antwrp.gsfc.nasa.gov/apod/ap960630.html ], including, the first spacecraft to travel through the asteroid belt and explore the outer Solar System [ http://antwrp.gsfc.nasa.gov/apod/ap961214.html ], the first spacecraft to visit Jupiter [ http://ccf.arc.nasa.gov/galileo_probe/index.html ], and the first to use a planet's gravity to change [ http://www.jpl.nasa.gov/basics/bsf4-1.htm#gravity ] its course and to reach solar-system-escape velocity. Pioneer 10's mission [ http://quest.arc.nasa.gov/pioneer10/mission/ index.html ] is nearing an end. Now exploring the distant reaches of the heliosphere [ http://earth.agu.org/revgeophys/neugeb01/neugeb01.html ] it will soon run out of sufficient electrical power to operate science instruments. However, the 570 lb. spacecraft [ ftp://ftp.hq.nasa.gov/pub/pao/pressrel/1997/97-031.txt ] will continue to coast and in 300,000 years or so it will pass within about 3 light years of nearby star [ http://cassfos02.ucsd.edu/public/nearest.html ] Ross 248. Ross 248 is a faint red dwarf just over 10 light years distant in the constellation Taurus. (Note: In 1998 Voyager 1 [ http://vraptor.jpl.nasa.gov/voyager/voyager.html ], launched 5 years later but traveling faster than Pioneer 10, became humanity's most distant spacecraft.) |
|
Apollo 17: Shorty Crater Pan
…
| Title |
Apollo 17: Shorty Crater Panorama |
| Explanation |
In December of 1972, Apollo 17 [ http://www.lpi.usra.edu/expmoon/Apollo17/ Apollo17.html ] astronauts Eugene Cernan and Harrison Schmitt spent about 75 hours on the Moon [ http://www.hq.nasa.gov/office/pao/History/alsj/ ] in the Taurus-Littrow [ http://www.hq.nasa.gov/alsj/a17/a17OTM.html ] valley, while colleague Ronald Evans orbited overhead. This sharp panorama is digitally stitched together from pictures taken by Cernan as he and Schmitt roamed the valley floor [ http://antwrp.gsfc.nasa.gov/apod/ap040417.html ]. Starting with a view of the imposing South Massif, scrolling the panorama to the right will reveal Schmitt and the lunar rover [ http://antwrp.gsfc.nasa.gov/apod/ap040605.html ] at the edge of Shorty Crater, near the spot where geologist Schmitt discovered orange [ http://antwrp.gsfc.nasa.gov/apod/ap010523.html ] lunar soil. The Apollo 17 crew returned with 110 kilograms of rock [ http://www.nasm.si.edu/exhibitions/cchoice/moonrocks/ moonrocks6.htm ] and soil samples, more than was returned from any of the other lunar landing sites [ http://www.boulder.swri.edu/~durda/Apollo/ landing_sites.html ]. Now thirty five years later, Cernan and Schmitt are still the last [ http://antwrp.gsfc.nasa.gov/apod/ap051210.html ] to walk on the Moon [ http://antwrp.gsfc.nasa.gov/apod/ap060826.html ]. |
|
Apollo 17's Moonship
| Title |
Apollo 17's Moonship |
| Explanation |
Awkward and angular looking, Apollo 17's lunar module Challenger [ http://nssdc.gsfc.nasa.gov/nmc/tmp/1972-096A.html ] was designed for flight [ http://users.specdata.com/home/pullo/lm_mis1.htm ] in the vacuum of space. This sharp picture from the command module America [ http://nssdc.gsfc.nasa.gov/nmc/tmp/1972-096C.html ], shows Challenger's ascent stage in lunar orbit. Small reaction control thrusters are at the sides of the moonship with the bell of the ascent rocket engine itself underneath. The hatch allowing access to the lunar surface [ http://www.hq.nasa.gov/alsj/a17/a17main.html ] is visible in the front and a round radar antenna appears at the top. This spaceship performed gracefully, landing on the moon and returning the Apollo astronauts to the orbiting command module in December of 1972 - but where is Challenger now? [ http://nssdc.gsfc.nasa.gov/planetary/lunar/ apolloloc.html ] Its descent stage remains [ http://www.boulder.swri.edu/~durda/Apollo/ ls_17_5aa.html ] at the Apollo 17 landing site [ http://www.boulder.swri.edu/~durda/Apollo/ landing_sites.html ], Taurus-Littrow [ http://cass.jsc.nasa.gov/pub/expmoon/Apollo17/ A17_lsite.html ]. The ascent stage was intentionally crashed nearby after being jettisoned from the command module prior to the astronauts' return [ http://www.hq.nasa.gov/alsj/a17/a17.homeward.html ] to planet Earth. Apollo 17's mission [ http://antwrp.gsfc.nasa.gov/apod/ap970504.html ] was the sixth and last time astronauts have landed on the moon. "Editor's note:" Eric Jones, Apollo Lunar Surface Journal [ http://www.hq.nasa.gov/alsj/ frame.html ] editor, comments, "If you look at the [... large, dark] triangular window, you'll see a bright rectangular area - which is the rendezvous window - beneath it, a bright arc. After much discussion, my team of volunteers and I concluded that the bright arc is the top of [mission commander] Gene Cernan's bubble helmet lit by sunlight ..." |
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Saturn and Vesta in Taurus
| Title |
Saturn and Vesta in Taurus |
| Explanation |
Last November, while skygazing [ http://pages.prodigy.net/pam.orman/ JoeGallery.html ] toward the constellation Taurus [ http://hou.lbl.gov/~vhoette/Explorations/StarHop/ ], astrophotographer Joe Orman arranged this time exposure to include the lovely Hyades and Pleiades star clusters in the field of his telephoto lens. A distance of 400 light-years [ http://school.discovery.com/ schooladventures/universe/itsawesome/lightyears/ ] for the close-knit Pleiades [ http://antwrp.gsfc.nasa.gov/apod/ap010506.html ] and 150 light-years for the V-shaped [ http://www.aspsky.org/mercury/mercury/9803/hyades.html ] Hyades [ http://astro.estec.esa.nl/Hipparcos/hyades.html ] puts these clusters in the general galactic neighborhood [ http://www.anzwers.org/free/universe/ 250lys.html ] of the Sun. Punctuating the Hyades' appearance, bright yellow Aldebaran [ http://www.astro.uiuc.edu/~kaler/sow/aldebaran.html ], 60 light-years away, is not actually a member of the cluster, but it is Taurus' brightest star. Above Aldebaran a yellower, even brighter Saturn [ http://space.jpl.nasa.gov/cgi-bin/wspace?tbody=6& vbody=3&month=11&day=17¢ury=20&decade=0&year=1&hour=00& minute=0&rfov=30&fovmul=-1&bfov=30 ] is is seen about 1.2 light-hours [ http://casswww.ucsd.edu/public/tutorial/Intro.html ] from our fair planet. Last and least massive [ http://aa.usno.navy.mil/hilton/asteroid_masses.htm ], one of the faint specks below Aldebaran is main-belt asteroid [ http://www.seds.org/nineplanets/nineplanets/ asteroids.html ] Vesta, a mere 13 light-minutes [ http://www.unmuseum.org/speed.htm ] away. Still cruising through Taurus, Vesta [ http://oposite.stsci.edu/pubinfo/PR/95/20.html ] is steadily approaching a close alignment or conjunction [ http://scienceworld.wolfram.com/astronomy/ Conjunction.html ] with Saturn on March 19. Need a program [ http://pages.prodigy.net/pam.orman/ JoeAlmanac2002.html ] to follow the players? Click on the image for a labeled version. |
|
M1: The Crab Nebula
| Title |
M1: The Crab Nebula |
| Explanation |
In the year 1054 a star in the constellation of Taurus exploded in a spectacular supernova [ http://antwrp.gsfc.nasa.gov/apod/lib/glossary.html#sn ] so bright it appeared to dominate the sky except for the Sun and Moon for many days. It left behind one of the most brilliant nebulae, listed first in Charles Messier's [ http://antwrp.gsfc.nasa.gov/apod/lib/glossary.html#messier ] list of nebulous sky objects. Today we know that the center of the nebula houses the remnant of the explosion: a spinning neutron star [ http://antwrp.gsfc.nasa.gov/apod/lib/glossary.html#ns ] called a pulsar. The Crab pulsar is visible in almost every part of the electromagnetic spectrum, and has been a useful astronomical tool. It is still unclear how the the pulsar emits the light that we see. For more information on M1 see The Electronic Universe Project's write-up. [ http://zebu.uoregon.edu/messier/m1.txt ] Many images of Messier objects can be found in The Electronic Universe Project's The Galaxy Gallery: Messier Objects. [ http://zebu.uoregon.edu/messier.html ] Tomorrow's picture: M15: A Great Globular Cluster |
|
Planets in the West
| Title |
Planets in the West |
| Explanation |
Have you seen any bright planets lately? Chances are if you've been outside under clear skies [ http://currentsky.com/ ] just after sunset, then you have. Now shining in the west as bright "stars [ http://nfo.edu/astro/planets.htm ]" in the night sky, are all five planets of the solar system known to [ http://www.nasm.si.edu/ceps/etp/discovery/ etpdiscovery.html ] ancient astronomers - Mercury, Venus, Mars [ http://mars.jpl.nasa.gov/ funzone.html ], Saturn, and Jupiter [ http://www.seds.org/nineplanets/nineplanets/ jupiter.html ]. Recorded from Holt, Michigan, USA about 40 minutes after sunset on April 14th, this digital image [ http://www.pa.msu.edu/people/frenchj/const/index2.html ] captures three of them, Venus, Mars, and Saturn [ http://www.jpl.nasa.gov/solar_system/planets/ saturn_index.html ], along with a young crescent Moon [ http://antwrp.gsfc.nasa.gov/apod/ap000728.html ]. Also indicated are the Pleiades [ http://antwrp.gsfc.nasa.gov/apod/ap010506.html ] star cluster and bright red giant star Aldebaran [ http://www.earthsky.com/Features/ Skywatching/pronounce.html ] in Taurus. Mercury [ http://www.psrd.hawaii.edu/Jan97/ MercuryUnveiled.html ], setting, is lost in the trees and glow along the horizon, while Jupiter is off the top of this view. The coming weeks [ http://www.darkhorizons.org/planets.htm ] will see photo opportunities galore as all five planets gradually move closer together, posing after sunset with the Moon and stars in the western sky [ http://www.skyviewcafe.com/skyview.shtml ]. Venus [ http://antwrp.gsfc.nasa.gov/apod/ap020330.html ], Mars, and Saturn will form the closest trio, drawing within a 5 degree circle (about the apparent size of your fist with arm extended) above Aldebaran by May 3rd. |
|
Lunar Module at Taurus-Littr
…
| Title |
Lunar Module at Taurus-Littrow |
| Explanation |
Can the Hubble Space Telescope [ http://hubblesite.org/ ] take a picture that shows the Apollo lunar modules [ http://users.specdata.com/home/pullo/lm_mis1.htm ] on the Moon? With its 2.4 meter diameter mirror [ http://hubblesite.org/sci.d.tech/nuts_.and._bolts/optics/ ], the smallest object that the Hubble can resolve [ http://astrosun.tn.cornell.edu/courses/astro201/ purpose.htm ] at the Moon's distance [ http://www.nineplanets.org/luna.html ] of around 400,000 kilometers is about 80 meters across. So, from low Earth orbit even Hubble's sharp vision can not image the Apollo lunar module descent stages, at most a few meters across, left behind [ http://antwrp.gsfc.nasa.gov/apod/ap981213.html ] at the lunar landing sites [ http://nssdc.gsfc.nasa.gov/planetary/lunar/ apolloland.html ]. A space telescope over ten times the size of Hubble could ... or a much smaller telescope in close lunar orbit. In fact, this picture does just resolve Apollo 17's Lunar Module, Challenger [ http://antwrp.gsfc.nasa.gov/apod/ap020105.html ], and its shadow on the cratered floor [ http://antwrp.gsfc.nasa.gov/apod/ap020128.html ] of the Taurus-Littrow valley in the Moon's Mare [ http://www.fourmilab.ch/earthview/lunarform/ maria.html ] Serenitatis. It was taken in 1972 from the Apollo 17 Command Module, America [ http://nssdc.gsfc.nasa.gov/nmc/tmp/ 1972-096A.html ], orbiting about 100 kilometers above the Moon's surface and covers an area about 1.1 kilometers wide. Using a web site [ http://www.boulder.swri.edu/~durda/Apollo/ landing_sites.html ] created by Dan Durda of Southwest Research Institute, armchair astronauts can explore orbital views of this and the 5 other Apollo [ http://www.hq.nasa.gov/office/pao/History/apollo.html ] lunar landing sites. |
|
Semeis 147: Supernova Remnan
…
| Title |
Semeis 147: Supernova Remnant |
| Explanation |
It's easy to get lost following the intricate filaments in this stunningly detailed image [ http://www.galaxyimages.com/s147.html ] of faint supernova remnant [ http://chandra.harvard.edu/xray_sources/ supernovas.html ] Simeis 147. Seen towards the constellation Taurus [ http://antwrp.gsfc.nasa.gov/apod/ap020118.html ] it covers nearly 3 degrees (6 full moons) on the sky corresponding to a width of 150 light-years at the stellar debris cloud's estimated distance of 3,000 light-years. On three separate nights in December 2001 and January 2002 astronomer [ http://www.galaxyimages.com/ ] Steve Mandel accumulated a total of over eight hours of exposure time to compose this image. He used an astronomical CCD camera, telephoto lens, and his specially designed adapter to allow such wide-field digital imaging [ http://www.galaxyimages.com/gallery.html ]. He also used a narrow H-alpha [ http://antwrp.gsfc.nasa.gov/apod/ap020822.html ] filter to transmit only the the light from recombining hydrogen atoms in the expanding nebulosity, defining the regions of shocked, glowing gas [ http://antwrp.gsfc.nasa.gov/apod/ap000426.html ]. This supernova remnant has an apparent age of about 100,000 years (light from the original explosion first reached Earth 100,000 years ago) but it is not the only aftermath [ http://antwrp.gsfc.nasa.gov/apod/ap011026.html ] of the massive stellar explosion. The cosmic catastrophe also left behind [ http://www.astro.psu.edu/users/pspm/ arecibo/s147/s147.html ] a spinning neutron star or pulsar, all that remains [ http://oposite.stsci.edu/pubinfo/PR/96/22/pulsars.html ] of the star's dense core. |
|
Apollo 17: Last on the Moon
| Title |
Apollo 17: Last on the Moon |
| Explanation |
In December of 1972, Apollo 17 [ http://antwrp.gsfc.nasa.gov/apod/ap020128.html ] astronauts Eugene Cernan and Harrison Schmitt spent about 75 hours [ http://www.hq.nasa.gov/alsj/a17/a17j.html ] on the Moon, in the Taurus-Littrow valley [ http://cass.jsc.nasa.gov/pub/ expmoon/Apollo17/A17_lsite.html ], while colleague Ronald Evans orbited overhead [ http://antwrp.gsfc.nasa.gov/apod/ap020628.html ]. Near the beginning of their third and final excursion [ http://www.hq.nasa.gov/alsj/a17/a17.eva3prep.html ] across the lunar surface [ http://www.hq.nasa.gov/office/pao/History/alsj/ ], Schmitt took this picture of Cernan flanked by an American flag and their lunar rover's [ http://antwrp.gsfc.nasa.gov/apod/ap010609.html ] umbrella-shaped high-gain antenna. The prominent [ http://www.hq.nasa.gov/alsj/a17/ a17.fam-mtn.html ] Sculptured Hills lie in the background while Schmitt's reflection can just be made out in Cernan's helmet. The Apollo 17 crew [ http://www.ari.net/nss/askastro/Apollo17/ home.html ] returned with 110 kilograms of rock and soil samples, more than from any of the other lunar landing sites [ http://www.boulder.swri.edu/~durda/Apollo/ landing_sites.html ]. And after thirty years, Cernan and Schmitt are still the last to walk [ http://www.alanbeangallery.com/ ] on the Moon. |
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The Pulsar Powered Crab
| Title |
The Pulsar Powered Crab |
| Explanation |
In the Summer of 1054 A.D. Chinese astronomers reported [ http://www.stsci.edu/pubinfo/PR/96/22/crabhist.html ] that a star in the constellation of Taurus [ http://bradley.bradley.edu/~dware/taurus.html ] suddenly became as bright as the full Moon. Fading slowly, it remained visible for over a year. It is now understood that a spectacular supernova explosion [ http://antwrp.gsfc.nasa.gov/apod/ap951027.html ] - the detonation of a massive star whose remains [ http://antwrp.gsfc.nasa.gov/apod/ap960509.html ] are now visible as the Crab Nebula [ http://antwrp.gsfc.nasa.gov/apod/ap951122.html ]- was responsible for the apparition. The core of the star collapsed [ http://www.stsci.edu/pubinfo/PR/96/22/pulsars.html ] to form a rotating neutron star [ http://astro.uchicago.edu/home/web/miller/nstar.html ] or pulsar [ http://pulsar.princeton.edu/rpr.shtml ], one of the most exotic objects known to 20th century astronomy. Like a cosmic lighthouse, the rotating Crab pulsar generates beams of radio, visible, x-ray and gamma-ray energy [ http://heasarc.gsfc.nasa.gov/cossc/descriptions/egret_pulsars.html ] which, as the name suggests, produce pulses as they sweep across our view. Using a stunning series of visible light images taken with the Hubble Space Telescope (HST) [ http://www.stsci.edu/pubinfo/PR/96/22.html ], astronomers have recently discovered spectacular pulsar powered motions within the Crab nebula. Highlights of this HST Crab "movie" [ http://www.stsci.edu/pubinfo/PR/96/22.html#Movies ] show wisps of material moving away from the pulsar at half the speed of light, a scintillating halo, and an intense knot of emission dancing, sprite-like, above the pulsar's pole. Only 6 miles wide but more massive than the sun, the pulsar's energy drives the dynamics and emission of the nebula itself which is more than 10 lightyears across. In the HST image above [ http://www.stsci.edu/pubinfo/PR/96/22/A.html ], the pulsar is the left most of the two bright central stars. |
|
Apollo 17: Boulder in Stereo
| Title |
Apollo 17: Boulder in Stereo |
| Explanation |
Humans left the Moon [ http://antwrp.gsfc.nasa.gov/apod/ap021212.html ] over thirty years ago, but donning red-blue glasses [ http://mpfwww.jpl.nasa.gov/MPF/mpf/ glasses.html ] (red for the left eye) you can share this excellent stereo [ http://antwrp.gsfc.nasa.gov/apod/ap010310.html ] perspective view of their last stomping ground. Recorded [ http://images.jsc.nasa.gov/images/pao/AS17/ 10075973.htm ] by Eugene Cernan, the scene depicts his fellow astronaut and geologist Harrison Schmitt next to a large split boulder on the floor of the narrow Taurus-Littrow valley located at the eastern edge of the lunar Mare Serenitatis. Parked nearby, their lunar rover [ http://antwrp.gsfc.nasa.gov/apod/ap010609.html ] is visible beyond the boulder at the right. During their stay the Apollo 17 astronauts explored [ http://www.hq.nasa.gov/office/pao/History/alsj/ ] the unusually dark terrain at the Taurus-Littrow landing site [ http://www.boulder.swri.edu/~durda/Apollo/ landing_sites.html ] and deployed explosives to test [ http://cass.jsc.nasa.gov/pub/expmoon/ Apollo17/A17_Experiments_LSPE.html ] the internal geology of the Moon. Apollo 17 returned the most lunar rocks and soil samples of any lunar mission [ http://www.badastronomy.com/bad/tv/foxapollo.html ]. |
|
The Crab that Played with th
…
| Title |
The Crab that Played with the Planet |
| Explanation |
Wandering [ http://es.rice.edu/ES/humsoc/Galileo/Things/ saturn.html ] through the constellation Taurus, Saturn made [ http://science.nasa.gov/headlines/y2002/13dec_saturn.htm ] its closest approach to planet Earth last month, tilting its lovely rings toward appreciative skygazers while rising high in midnight skies. On January 4th and 5th, Saturn also crossed in front of the high and far-off [ http://www.boop.org/jan/justso/crab.htm ] Crab Nebula (M1), a cosmic cloud of debris from a stellar explosion and first on the list of astronomer Charles Messier's [ http://antwrp.gsfc.nasa.gov/apod/ap960626.html ] celestial sights. But Saturn and the Crab [ http://www.marcush.net/astronomy/m1.html ] made poor playmates, as light from the bright planet overwhelmed the the diffuse nebula, all but hiding the Crab during the transit [ http://www.surveyor.in-berlin.de/himmel/ indexe.html#saturn ]. Taken on January 2nd, a few days before their closest encounter, this composite digital image illustrates the problem. The subtle nebula [ http://www.seds.org/messier/m/m001.html ] is just visible at the right, while on the left, light from a drastically over-exposed Saturn overflows its pixels. Composited into the image is a correctly exposed picture of ringed Saturn [ http://antwrp.gsfc.nasa.gov/apod/ap021104.html ] with the Saturnian moons labeled. The well-exposed Saturn image was also taken on January 2nd, but captured with an exposure lasting only a fraction of a second, in contrast with the tens of seconds of exposure time required to reveal the Crab. |
|
Hale-Bopp: Climbing Into Sou
…
| Title |
Hale-Bopp: Climbing Into Southern Skies |
| Explanation |
Fighting the glow of the setting sun and the city lights of Cape Town, South Africa, comet Hale-Bopp [ http://www.saao.ac.za/sky/comet.html ] is just visible near the center of this panoramic view - photographed on May 3rd. In the foreground is the Strand beach front, about 50 km East of Cape Town, while the Cape Peninsula mountain ranges can be seen at the left along the horizon. The bright star visible above and to the left of the comet is the red giant Aldebaran [ http://www.astro.wisc.edu/~dolan/constellations/hr/1457.html ] in the constellation Taurus. As Hale-Bopp [ http://antwrp.gsfc.nasa.gov/apod/ap970505.html ] continues its outbound journey during the month of May it will climb higher into evening southern skies. Still a bright comet [ http://galileo.ivv.nasa.gov/comet/news82.html ] it is now providing an enjoyable and much anticipated showing [ http://galileo.ivv.nasa.gov/comet/brown4.html ] for Southern Hemisphere observers [ http://www.saao.ac.za/ ]. |
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Help Aldebaran Map the Moon
| Title |
Help Aldebaran Map the Moon |
| Explanation |
Turn on your camcorder, go outside, and become an astronomer. How? [ http://www.sky.net/~robinson/0729prls.htm ]. Tomorrow morning, our Moon [ http://antwrp.gsfc.nasa.gov/apod/ap970728.html ap960730.html ] will pass directly in front of Aldebaran [ http://www.bo.astro.it/copernic/alde-eng.html ], the brightest star in this picture and in entire constellation of Taurus [ http://www.astro.wisc.edu/~dolan/constellations/constellations/Taurus.html ]. Aldebaran [ http://antwrp.gsfc.nasa.gov/apod/ap970728.html http://www.adler.uchicago.edu/ISE/TAURUS4.HTM ] is visible to the left and below Comet Hale-Bopp in the above photograph [ http://galileo.ivv.nasa.gov/comet/cat1.html ], which was taken on April 30th in Tenerife [ http://www.cistia.es/cabildotf/ ], Spain. This occultation is valuable because disappearance times from different locations can be used to map the height of the lunar terrain [ http://antwrp.gsfc.nasa.gov/apod/ap960420.html ] at the occultation points. You can help by clicking here [ http://www.sky.net/~robinson/iotandx.htm ], where a site will detail how to tape a familiar cable channel and then take your still-running camcorder [ http://www.sky.net/~robinson/0729camc.htm ] outside to tape the occultation of Aldebaran [ http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1983ApJ%2E%2E%2E265%2E%2E325S&db_key=AST&nosetcookie=1 ] by the Moon. You can then donate your VCR tape to science by mailing it to this address [ http://www.sky.net/~robinson/0729prls.htm ]. Leave yourself plenty of time [ http://www.sky.net/~robinson/0729tysd.htm ] for a practice run and be sure to check the weather before going to a lot of trouble! |
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Bright Meteor, Dark Sky
| Title |
Bright Meteor, Dark Sky |
| Explanation |
Has Orion the Hunter acquired a new weapon? If you turn your head sideways (counterclockwise) you might notice the familiar constellation of Orion [ http://www.astro.wisc.edu/~dolan/constellations/constellations/Orion.html ], particularly the three consecutive bright stars that make up Orion's belt [ http://www.adler.uchicago.edu/ISE/ORION4.HTM ]. But in addition to the stars that compose his sword [ http://www.adler.uchicago.edu/ISE/ORION4.HTM ], Orion [ http://www.astro.wisc.edu/~dolan/constellations/extra/OrionStory.html ] appears to have added some sort of futuristic light-saber, possibly in an attempt to finally track down Taurus the Bull [ http://astro.gmu.edu/constellation/TAU.html ]. Actually, the bright streak is a meteor from the Perseid Meteor Shower [ http://antwrp.gsfc.nasa.gov/apod/ap970811.html ], a shower that put on an impressive display last Tuesday morning, when this photograph was taken. This meteor [ http://www.seds.org/nineplanets/nineplanets/meteorites.html ] was likely a small icy pebble shed years ago from Comet Swift-Tuttle [ http://antwrp.gsfc.nasa.gov/apod/ap960219.html ] that evaporated as it entered Earth's atmosphere [ http://liftoff.msfc.nasa.gov/academy/space/atmosphere.html ]. |
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Apollo 17: Boulder on the Mo
…
| Title |
Apollo 17: Boulder on the Moon |
| Explanation |
Twenty five years ago humans roamed the Moon [ http://www.nasm.edu/APOLLO/LunarTop10.html ]. Pictured here during the last moon landing [ http://antwrp.gsfc.nasa.gov/apod/ap970504.html ], scientist-astronaut Harrison Schmitt [ http://www.hq.nasa.gov/alsj/a17/a17.crew.html#jackbio ] was photographed [ http://images.jsc.nasa.gov/images/pao/AS17/10075973.htm ] standing next to a huge, split boulder. Apollo 17 [ http://www.nasm.edu/APOLLO/AS17/Apollo17_fact.html ] was one of six missions that landed humans on the moon [ http://www.hq.nasa.gov/alsj/ ] and returned them safely. Apollo 17 [ http://www.nasm.edu/APOLLO/AS17/Apollo17_MissionObj.html ] explored the unusually dark terrain at the Taurus-Littrow landing site, deployed explosives to test the internal geology of the Moon [ http://bang.lanl.gov/solarsys/apo17.htm ], and returned the most rocks of any lunar mission. |
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Apollo 17's Lunar Rover
| Title |
Apollo 17's Lunar Rover |
| Explanation |
In December of 1972, Apollo 17 [ http://antwrp.gsfc.nasa.gov/apod/ap031109.html ] astronauts Eugene Cernan and Harrison Schmitt spent about 75 hours exploring [ http://www.hq.nasa.gov/alsj/a17/a17j.html ] the Moon's Taurus-Littrow valley [ http://www.lpi.usra.edu/expmoon/Apollo17/ A17_lsite.html ] while colleague Ronald Evans orbited overhead [ http://antwrp.gsfc.nasa.gov/apod/ap020628.html ]. Cernan and Schmitt were the last humans to walk or ride on the Moon - aided in their explorations [ http://antwrp.gsfc.nasa.gov/apod/ap010523.html ] by a Lunar Roving Vehicle [ http://ares.jsc.nasa.gov/HumanExplore/Exploration/ EXLibrary/docs/ApolloCat/Part1/LRV.htm ]. The skeletal-looking lunar rover was [ http://www.hq.nasa.gov/office/pao/History/alsj/ lrvhand.html ] just over 10 feet long, 6 feet wide and easily carried astronauts, equipment, and rock samples in the Moon's [ http://nssdc.gsfc.nasa.gov/planetary/factsheet/moonfact.html ] low gravity (about 1/6 Earth's). In this picture [ http://www.hq.nasa.gov/alsj/a17/images17.html ], Cernan stands at the back of the rover which carried the two astronauts in lawn-chair style seats. An umbrella-shaped high gain antenna and TV camera are mounted in the front. Powered by four 1/4 horsepower electric motors, one for each wheel [ http://antwrp.gsfc.nasa.gov/apod/ap040417.html ], this rover was driven a total of about 18 miles across the lunar surface [ http://www.hq.nasa.gov/alsj/frame.html ]. Its estimated top speed was a blazing 8 miles per hour. |
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Canaries Sky
| Title |
Canaries Sky |
| Explanation |
This gorgeous view of [ http://www.mclink.it/personal/MC7872/deepvoid/deepskyen.htm ] stars, nebulae, and the Milky Way comes from the dark night sky [ http://www.mclink.it/personal/MC7872/deepvoid/index.html ] above the lovely island of La Palma in the Canaries archipelago [ http://www.ing.iac.es/lapalma/history.html ]. The picture was made by a group of experienced astrophotographers who traveled there to take advantage of the ideal observing conditions [ http://www.ing.iac.es/ ] near La Palma's Observatorio del Roque de los Muchachos [ http://www.ing.iac.es/orm/orm.html ]. Skygazers can easily pick out several of their favorite astronomical objects [ http://antwrp.gsfc.nasa.gov/apod/ap980214.html ] in this wide angle time exposure which covers about 40 degrees on winter the sky. Faint stars along the plane of our Galaxy compose the delicate, luminous band of the Milky Way [ http://antwrp.gsfc.nasa.gov/apod/ap980226.html ] stretching across the image from the bottom left. The familiar constellation [ http://www.adler.uchicago.edu/ISE/menu.html ] of Orion [ http://antwrp.gsfc.nasa.gov/apod/ap970817.html ] the hunter is also easy to find, with glowing nebulae [ http://antwrp.gsfc.nasa.gov/apod/ap980127.html ] highlighting [ http://antwrp.gsfc.nasa.gov/apod/ap980201.html ] the hunter's belt and sword. Orion's [ http://antwrp.gsfc.nasa.gov/apod/ap961202.html ] famous red giant star Betelgeuse [ http://antwrp.gsfc.nasa.gov/apod/ap970216.html ], near picture center, has a yellowish cast and Rigel is [ http://antwrp.gsfc.nasa.gov/apod/ap980209.html ] the bright star in Orion at lower right. Brilliant white Sirius [ http://antwrp.gsfc.nasa.gov/apod/ap960902.html ], near the bottom, is the brightest star in the picture (and in Earth's night sky). Sirius, is part of the constellation Canis Major [ http://www.astro.wisc.edu/~dolan/constellations/ constellations/Canis_Major.html ] (Big Dog). Across the Milky Way, above and to the left of Sirius, is slightly less brilliant Procyon, brightest star of Canis Minor [ http://www.astro.wisc.edu/~dolan/constellations/ constellations/Canis_Minor.html ]. A V-shaped group [ http://www.adler.uchicago.edu/ISE/HYAPLEIA.HTM ] of yellowish stars at the upper right, part of Taurus the bull [ http://www.astro.wisc.edu/~dolan/constellations/ constellations/Taurus.html ], is dominated by the red giant Aldebaran [ http://www.bo.astro.it/copernic/alde-eng.html ]. |
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An Extrasolar Planet?
| Title |
An Extrasolar Planet? |
| Explanation |
This infrared Hubble Space Telescope view [ http://oposite.stsci.edu/pubinfo/pr/1998/19/index.html ] may contain the first ever direct image of a planet outside our own solar system. The picture shows a very young double star located about 450 light-years away toward the constellation of Taurus [ http://www.astro.wisc.edu/~dolan/constellations/ constellations/Taurus.html ]. Cataloged as TMR-1 (Taurus Molecular Ring star 1), the binary system is still embedded in the dust cloud that formed it. This double star and dust cloud are the brightest grouping in the picture, glowing strongly at infrared wavelengths. A filament extends from the binary system toward the lower left and points toward the spot of light representing the candidate planet. Astronomers believe this planet is a "runaway" object [ http://oposite.stsci.edu/pubinfo/pr/1998/19/astrofile.html ] which was gravitationally ejected, the filament tracing the path to its present location at about 1500 times the Earth-Sun distance [ http://antwrp.gsfc.nasa.gov/apod/ap960727.html ] from the parent star system. Models suggest that the planet and binary system [ http://antwrp.gsfc.nasa.gov/apod/ap970219.html ] are a mere 300,000 years old, with the planet having a mass of about 2 to 3 Jupiters. Future observations to look for the planet's continued runaway motion and spectral signatures should be able to confirm the nature of this object. While this and other tantalizing discoveries [ http://antwrp.gsfc.nasa.gov/apod/ap971005.html ] of extrasolar planetary objects [ http://wwwusr.obspm.fr/departement/darc/planets/encycl.html ] and protoplanetary disks [ http://antwrp.gsfc.nasa.gov/apod/ap961207.html ] don't seem to offer direct examples of solar systems [ http://www.empire.net/~whatmoug/Extrasolar/extrasolar_visions.html ] like our own [ http://www.seds.org/nineplanets/nineplanets/nineplanets.html ], they do strongly hint that planet formation [ http://www.sciam.com/explorations/052796explorations.html ] is a varied and common process. |
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Pioneer 10: The First 6 Bill
…
| Title |
Pioneer 10: The First 6 Billion Miles |
| Explanation |
"Q:" What was made by humans and is 6.5 billion miles away? "A:" Pioneer 10 - and last year was the 25th anniversary of its launch [ http://quest.arc.nasa.gov/pioneer10/ ]. More than 9.5 light-hours distant, Pioneer 10 is presently [ http://spaceprojects.arc.nasa.gov/Space_Projects/pioneer/PNStat.html ] about twice as far from the Sun as Pluto [ http://antwrp.gsfc.nasa.gov/apod/ap970204.html ], bound for interstellar space at 28,000 miles per hour. The distinction of being the first human artifact to venture beyond the Solar System [ http://spaceprojects.arc.nasa.gov/Space_Projects/pioneer/path.html ] is just one in a long list of firsts for this spacefaring ambassador [ http://antwrp.gsfc.nasa.gov/apod/ap960630.html ], including, the first spacecraft to travel through the asteroid belt and explore the outer Solar System [ http://antwrp.gsfc.nasa.gov/apod/ap961214.html ], the first spacecraft to visit Jupiter [ http://ccf.arc.nasa.gov/galileo_probe/index.html ], the first to use a planet's gravity to change its course and to reach solar-system-escape velocity, and the first spacecraft to pass beyond the known planets. Pioneer 10's mission is nearing an end [ http://quest.arc.nasa.gov/pioneer10/mission/index.html ] - now exploring the distant reaches of the heliosphere [ http://earth.agu.org/revgeophys/neugeb01/neugeb01.html ] it will soon run out of sufficient electrical power to operate science instruments. However, the 570 lb. spacecraft will continue to coast [ ftp://ftp.hq.nasa.gov/pub/pao/pressrel/1997/97-031.txt ] and in 30,000 years or so it will pass within about 3 light years of a nearby star [ http://antwrp.gsfc.nasa.gov/apod/ap961019.html ] known as Ross 248. Ross 248 is a faint red dwarf just over 10 light years distant in the constellation Taurus. (Note: This year Voyager 1 [ http://vraptor.jpl.nasa.gov/voyager/voyager.html ], launched 21 years ago but traveling faster than Pioneer 10, became humanity's most distant spacecraft.) |
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The Pulsar Powered Crab
| Title |
The Pulsar Powered Crab |
| Explanation |
In the Summer of 1054 [ http://www.chaco.com/park/archaeology/nebula.html ] A.D. Chinese astronomers reported [ http://www.stsci.edu/pubinfo/PR/96/22/crabhist.html ] that a star in the constellation of Taurus [ http://www.astro.wisc.edu/~dolan/constellations/ constellations/Taurus.html ] suddenly became as bright as the full Moon. Fading slowly, it remained visible for over a year. It is now understood that a spectacular supernova explosion [ http://antwrp.gsfc.nasa.gov/apod/ap980217.html ] - the detonation of a massive star whose remains [ http://antwrp.gsfc.nasa.gov/apod/ap980613.html ] are now visible as the Crab Nebula [ http://antwrp.gsfc.nasa.gov/apod/ap951122.html ]- was responsible for the apparition. The core of the star collapsed [ http://www.stsci.edu/pubinfo/PR/96/22/pulsars.html ] to form a rotating neutron star [ http://astro.uchicago.edu/home/web/miller/nstar.html ] or pulsar [ http://pulsar.princeton.edu/rpr.shtml ], one of the most exotic objects known to 20th century astronomy. Like a cosmic lighthouse, the rotating Crab pulsar generates beams of radio, visible, x-ray and gamma-ray energy [ http://heasarc.gsfc.nasa.gov/cossc/descriptions/egret_pulsars.html ] which, as the name suggests, produce pulses as they sweep across our view. Using a stunning series of visible light images taken with the Hubble Space Telescope (HST) [ http://www.stsci.edu/pubinfo/PR/96/22.html ], astronomers have discovered spectacular pulsar powered motions within the Crab nebula. Highlights of this HST Crab "movie" [ http://www.stsci.edu/pubinfo/PR/96/22.html#Movies ] show wisps of material moving away from the pulsar at half the speed of light, a scintillating halo, and an intense knot of emission dancing, sprite-like, above the pulsar's pole. Only 6 miles wide but more massive than the sun, the pulsar's energy drives the dynamics and emission of the nebula itself which is more than 10 lightyears across. In this HST image [ http://www.stsci.edu/pubinfo/PR/96/22/A.html ], the pulsar is the left most of the two bright central stars. |
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Twin Proto-Planetary Disks
| Title |
Twin Proto-Planetary Disks |
| Explanation |
Sun-like stars [ http://imagine.gsfc.nasa.gov/docs/science/know_l2/sun_parts.html ] are forming - and probably planets too [ http://wwwusr.obspm.fr/departement/darc/planets/encycl.html ] - hidden inside [ http://donald.phast.umass.edu/theses/dianne/chap1/node5.html ] Lynds 1551, an interstellar cloud of molecular gas and dust in the constellation [ http://www.mtwilson.edu/Education/ConQuiz/ ] Taurus. Using new receivers, coordinated radio telescopes at the Very Large Array [ http://www.nrao.edu/vla/html/VLAhome.shtml ] near Socorro, New Mexico, USA, can now sharply image the dusty proto-planetary disks surrounding these young stars at radio wavelengths. Just announced, this exciting example [ http://www.nrao.edu/pr/protodisks.html ] shows a false-color radio [ http://antwrp.gsfc.nasa.gov/apod/ap980917.html ] picture of twin disks in a double star system [ http://antwrp.gsfc.nasa.gov/apod/ap970219.html ]! A yellow bar indicates the scale in astronomical units (AUs) where one AU is the average distance between the Earth and Sun. The stars (unseen near the center of each disk) are about 45 AUs apart, comparable to the radius of the orbit of Pluto [ http://nssdc.gsfc.nasa.gov/planetary/factsheet/plutofact.html ]. Similar proto-planetary disks [ http://antwrp.gsfc.nasa.gov/apod/ap980423.html ] have been seen around single stars, but these twin disks are much smaller, each limited in size by the gravity of the nearby companion star [ http://astrosun.tn.cornell.edu/courses/astro201/kepler_binary.htm ]. In fact, if large planets form orbiting near the edges of these disks they may be ejected from the binary system [ http://antwrp.gsfc.nasa.gov/apod/ap980529.html ]. |
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GLAST Gamma-Ray Sky Simulati
…
| Title |
GLAST Gamma-Ray Sky Simulation |
| Explanation |
This simulated image models the intensities of gamma rays [ http://cossc.gsfc.nasa.gov/cossc/outreach/nasm/VU/ ] with over 40 million times the energy of visible light, and represents how the sky might appear to the proposed Gamma-ray Large Area Space Telescope [ http://glast.gsfc.nasa.gov ] (GLAST) after its first year in orbit. Familiar steady stars are absent from the dramatic 80x80 degree field which looks directly away from the center of the Galaxy. Instead, the Geminga [ http://imagine.gsfc.nasa.gov/docs/science/how_l2/timing.html ] and Crab pulsars [ http://oposite.stsci.edu/pubinfo/pr/96/22.html ] - bizarre, spinning stellar corpses known to be neutron stars [ http://antwrp.gsfc.nasa.gov/apod/ap980425.html ] - are the two brightest gamma-ray sources. These and other bright objects in the field, dense pulsars [ http://antwrp.gsfc.nasa.gov/apod/ap980211.html ], monstrous active galaxies [ http://imagine.gsfc.nasa.gov/docs/science/know_l2/active_galaxies.html ], and still unknown sources, have been detected by the Energetic Gamma-Ray Experiment Telescope [ http://cossc.gsfc.nasa.gov/cossc/egret/ ] (EGRET) on the orbiting Compton Gamma-Ray Observatory [ http://cossc.gsfc.nasa.gov ]. However, most of the simulated point sources are new - extrapolating current ideas and anticipating discoveries resulting from GLAST's improved gamma-ray vision [ http://glast.gsfc.nasa.gov/Anticen/ ]. The central broad band of faint gamma-ray emission is due to high-energy cosmic rays [ http://antwrp.gsfc.nasa.gov/apod/ap980618.html ] colliding with interstellar gas in the outer spiral arms of the Milky Way [ http://antwrp.gsfc.nasa.gov/apod/ap980523.html ], while below is a diffuse energetic glow from prominent molecular clouds [ http://antwrp.gsfc.nasa.gov/apod/ap970430.html ] in Monoceros, Orion, Auriga, and Taurus. Intended to explore [ http://perry.sonoma.edu/ ] the most extreme energy sources in the distant cosmos [ http://universe.gsfc.nasa.gov/ ] and planned for launch in 2005, the GLAST mission [ http://wwwmipd.gsfc.nasa.gov/glast/glast.htm ] is under development [ http://glast.gsfc.nasa.gov/Summary/ ] by NASA and a collaboration of U. S. and international partners. |
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Simeis 147: Supernova Remnan
…
| Title |
Simeis 147: Supernova Remnant |
| Explanation |
It's easy to get lost following the intricate filaments in this detailed image [ http://www.robgendlerastropics.com/Semeis.html ] of faint supernova remnant [ http://chandra.harvard.edu/xray_sources/ supernovas.html ] Simeis 147. Seen towards the constellation Taurus [ http://www.allthesky.com/constellations/taurus/ ] it covers nearly 3 degrees (6 full moons) on the sky corresponding to a width of 150 light-years at the stellar debris cloud's estimated distance of 3,000 light-years. The color composite image includes eight hours of exposure time with an H-alpha [ http://www.robgendlerastropics.com/ HARGB.html ] filter, transmiting only the light from recombining hydrogen atoms in the expanding nebulosity and tracing the regions of shocked, glowing gas [ http://antwrp.gsfc.nasa.gov/apod/ap000426.html ]. This supernova remnant has an apparent age of about 100,000 years - meaning light from the massive stellar explosion first reached Earth 100,000 years ago - but this expanding remnant is not the only aftermath [ http://antwrp.gsfc.nasa.gov/apod/ap011026.html ]. The cosmic catastrophe also left behind [ http://arxiv.org/abs/ astro-ph/0306628 ] a spinning neutron star or pulsar, all that remains [ http://hubblesite.org/newscenter/newsdesk/archive/releases/ 1996/22/astrofile/#2 ] of the original star's core. |
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Apollo 17's Moonship
| Title |
Apollo 17's Moonship |
| Explanation |
Awkward and angular looking, Apollo 17's lunar module Challenger [ http://nssdc.gsfc.nasa.gov/cgi-bin/database/www-nmc?72-096C ] was designed for flight [ http://users.specdata.com/home/pullo/lm_mis1.htm ] in the vacuum of space. This sharp picture from the command module America [ http://nssdc.gsfc.nasa.gov/cgi-bin/database/www-nmc?72-096A ], shows Challenger's ascent stage in lunar orbit. Small reaction control thrusters are at the sides of the moonship with the bell of the ascent rocket engine itself underneath. The hatch allowing access to the lunar surface [ http://www.hq.nasa.gov/alsj/a17/a17main.html ] is visible in the front and a round radar antenna appears at the top. This spaceship performed gracefully, landing on the moon and returning the Apollo astronauts to the orbiting command module in December of 1972 - but where is Challenger now? [ http://nssdc.gsfc.nasa.gov/planetary/lunar/apolloloc.html ] Its descent stage remains at the Apollo 17 landing site, Taurus-Littrow [ http://cass.jsc.nasa.gov/pub/expmoon/Apollo17/A17_lsite.html ]. The ascent stage crashed nearby after being jettisoned from the command module prior to the astronauts' return [ http://www.hq.nasa.gov/alsj/a17/a17.homeward.html ] to planet Earth. Apollo 17's mission [ http://antwrp.gsfc.nasa.gov/apod/ap970504.html ] was the sixth and last time astronauts have landed on the moon. |
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Portrait of RY Tauri
| Title |
Portrait of RY Tauri |
| Explanation |
A star emerges from its natal cloud of gas and dust in this tantalizing portrait [ http://www.gemini.edu/ index.php?option=content&task=view&id=129&Itemid=42 ] of RY Tauri, a small stellar nursery [ http://antwrp.gsfc.nasa.gov/apod/ap010604.html ] at the edge of the Taurus molecular cloud, a mere 450 light-years away. Illuminating a region that spans about 2/3 of a light-year, the youthful [ http://www.daviddarling.info/encyclopedia/T/TTauri.html ], central star is large, cool [ http://www.go.ednet.ns.ca/~larry/stars/prtostar.html ], and known to vary [ http://www.aavso.org/vstar/vsots/0201.shtml ] in brightness. Still collapsing, in a few million years the star's winds [ http://www.phy6.org/Education/wsolwind.html ] will likely clear out the gas and dust clouds, as it settles down to become a steady main sequence star like the Sun. What remains could well include a planetary system [ http://antwrp.gsfc.nasa.gov/apod/ap021011.html ]. The image data for RY Tauri is from the Gemini Observatory [ http://antwrp.gsfc.nasa.gov/apod/ap030909.html ], on Mauna Kea, Hawaii -- based on observations proposed by [ http://hia-iha.nrc-cnrc.gc.ca/cgo/contest_e.html ] the Astronomy Club of Dorval, Quebec. |
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