The pixelated planet above is actually our own planet Earth seen in gamma rays [ http://universe.nasa.gov/press/2005/050325b.html ] - the most energetic form of light. In fact, the gamma rays [ http://cossc.gsfc.nasa.gov/epo/vu/overview/whatare/ process.html ] used to construct this view [ http://heasarc.gsfc.nasa.gov/docs/objects/heapow/archive/solar_system/cgro_earth.html ] pack over 35 million electron volts [ http://hyperphysics.phy-astr.gsu.edu/hbase/ electric/ev.html#c1 ] (MeV) compared to a mere two electron volts (eV) for a typical visible light photon. The Earth's gamma-ray glow [ http://antwrp.gsfc.nasa.gov/apod/ap990417.html ] is indeed very faint, and this image was constructed by combining data from seven years of exposure during the life of the Compton Gamma Ray Observatory [ http://cossc.gsfc.nasa.gov/ ], operating [ http://cossc.gsfc.nasa.gov/epo/vu/overview/gro/ gro.html ] in Earth orbit from 1991 to 2000. Brightest near the edge and faint near the center, the picture indicates that the gamma rays are coming from high in Earth's atmosphere. The gamma rays are produced as the atmosphere interacts with high energy cosmic rays [ http://antwrp.gsfc.nasa.gov/apod/ap001202.html ] from space, blocking [ http://coolcosmos.ipac.caltech.edu/cosmic_classroom/ multiwavelength_astronomy/multiwavelength_astronomy/ orbit.html ] the harmful radiation from reaching the surface. Astronomers need to understand [ http://xxx.lanl.gov/abs/astro-ph/0410487 ] Earth's gamma-ray glow well as it can interfere with observations of cosmic gamma-ray sources [ http://cossc.gsfc.nasa.gov/epo/vu/index.html ] like pulsars, supernova remnants [ http://antwrp.gsfc.nasa.gov/apod/ap041105.html ], and distant active galaxies powered by supermassive black holes [ http://csep10.phys.utk.edu/astr162/lect/active/ smblack.html ].
BATSE GRB Final Sky Map
Title
BATSE GRB Final Sky Map
Explanation
What causes the most powerful explosions in the universe? The BATSE [ http://gammaray.msfc.nasa.gov/batse/ ] modules that flew on the Compton Gamma Ray Observatory [ http://cossc.gsfc.nasa.gov/cgro/index.html ] allowed more insight into enigmatic gamma-ray burst [ http://www.sciam.com/0797issue/0797fishman.html ] (GRB) explosions than ever before. From 1991-2000, BATSE detected 2704 GRBs, much more than ever previously recorded. The above final sky map [ http://gammaray.msfc.nasa.gov/batse/grb/skymap/ ] of GRB locations (and fluence [ http://science.nasa.gov/newhome/headlines/ast21oct99_1.htm ]) shows them to occur at random locations on the sky - strong evidence [ http://antwrp.gsfc.nasa.gov/debate/debate95.html ] that GRBs [ http://science.msfc.nasa.gov/newhome/help/tutorials/batse/chapter4.htm ] occur across our universe and not in sky bands indicative of our Solar System [ http://antwrp.gsfc.nasa.gov/apod/ap990529.html ] or our Galaxy [ http://antwrp.gsfc.nasa.gov/apod/ap980321.html ]. As with any successful mission, answers create more questions, and astronomers continue to puzzle over what object creates a GRB [ http://glast.gsfc.nasa.gov/GSD/sec06.html ], and what happens in the initial stages of the explosion. BATSE [ http://www.batse.com/ ]'s legacy includes recording [ http://umbra.nascom.nasa.gov/batse/batse_years.html ] 1190 gamma-ray flares from the Sun [ http://hesperia.gsfc.nasa.gov/sftheory/ ] and the discovery of Terrestrial Gamma Flashes [ http://gammaray.msfc.nasa.gov/batse/tgf/ ], unusual bursts of gamma rays [ http://antwrp.gsfc.nasa.gov/apod/ap000324.html ] that emanate from the Earth [ http://antwrp.gsfc.nasa.gov/apod/ap990131.html ] itself. To protect people from an uncontrolled re-entry, Compton [ http://antwrp.gsfc.nasa.gov/apod/ap000116.html ] was recently crashed [ http://antwrp.gsfc.nasa.gov/apod/ap000603.html ] into the Pacific Ocean [ http://www.odci.gov/cia/publications/factbook/zn.html ].
The Milky Way's Gamma-Ray Ha
…
Title
The Milky Way's Gamma-Ray Halo
Explanation
Our Milky Way galaxy appears to be surrounded by a halo of gamma rays [ http://tigre.ucr.edu/halo/halo.html ]. Gamma rays are the most energetic form of electromagnetic radiation [ http://imagine.gsfc.nasa.gov/docs/science/know_l1/emspectrum.html ], with more than a hundred thousand times the energy of visible light, but known gamma-ray sources [ http://antwrp.gsfc.nasa.gov/apod/ap970222.html ] don't account for the diffuse distribution of this high-energy glow. This surprising result is based on data [ http://tigre.ucr.edu/halo/tipsh.html ] from the EGRET instrument onboard the Compton Gamma Ray Observatory [ http://antwrp.gsfc.nasa.gov/apod/ap970606.html ]. In this false color all-sky image centered on the Milky Way [ http://antwrp.gsfc.nasa.gov/apod/ap970517.html ], the brown and green regions indicate brighter, known sources of gamma-rays. The galactic center and plane clearly standout as do some distant galaxies seen near the top and bottom of the picture. The dim, blue regions above and below the plane correspond to our Galaxy's unexpected gamma-ray halo. " What causes the halo? " Future gamma-ray telescopes [ http://www-glast.stanford.edu ] could solve this mystery. However, the excitement has already inspired tantalizing speculation about the solution including, collisions of low energy photons with high-energy cosmic rays [ http://antwrp.gsfc.nasa.gov/apod/ap961016.html ], high energy electrons accelerated by a previous burst of Milky Way star formation [ http://antwrp.gsfc.nasa.gov/apod/ap971027.html ], and exotic interacting particles which make up Dark Matter [ http://antwrp.gsfc.nasa.gov/htmltest/gifcity/matter.html ].
The Gamma Ray Sky
Title
The Gamma Ray Sky
Explanation
What if you could "see" gamma rays? [ http://cossc.gsfc.nasa.gov/cossc/nasm/VU/vu.html ] If you could, the sky would seem to be filled [ http://cossc.gsfc.nasa.gov/cossc/pics.html ] with a shimmering high-energy glow from the most exotic [ http://cossc.gsfc.nasa.gov/cossc/news.html ] and mysterious objects in the Universe [ http://antwrp.gsfc.nasa.gov/apod/ap971218.html ]. In the early 1990s NASA's orbiting Compton Observatory [ http://antwrp.gsfc.nasa.gov/apod/ap970606.html ], produced this premier vista of the entire sky in gamma rays [ http://cossc.gsfc.nasa.gov/cossc/nasm/VU/overview/ g_rayuni/g_rayuni.html ] - photons with more than 40 million times the energy of visible light [ http://cossc.gsfc.nasa.gov/cossc/whatgam.html ]. The diffuse gamma-ray glow from the plane of our Milky Way Galaxy [ http://antwrp.gsfc.nasa.gov/apod/ap970517.html ] runs horizontally through the false color image. The brightest spots in the galactic plane (right of center) are pulsars [ http://antwrp.gsfc.nasa.gov/apod/ap980211.html ] - spinning magnetized neutron stars formed in the violent crucibles of stellar explosions [ http://antwrp.gsfc.nasa.gov/apod/ap961114.html ]. Above and below the plane, quasars [ http://antwrp.gsfc.nasa.gov/apod/ap971206.html ], believed to be powered by supermassive black holes [ http://antwrp.gsfc.nasa.gov/apod/ap971019.html ], produce gamma-ray beacons at the edges of the universe. The nature of many [ http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1996A%26AS%2E%2E120C%2E465M&db_key=AST ] of the fainter sources remains unknown [ http://www-glast.stanford.edu/ ].
Gamma-Ray Moon
Title
Gamma-Ray Moon
Explanation
If you could see gamma rays [ http://antwrp.gsfc.nasa.gov/apod/ap000722.html ] - photons with a million or more times the energy of visible light - the Moon would appear brighter than the Sun! The startling notion is demonstrated by this image of the Moon from the Energetic Gamma Ray Experiment Telescope (EGRET [ http://cossc.gsfc.nasa.gov/docs/cgro/cgro/egret.html ]) in orbit on NASA's Compton Gamma Ray Observatory [ http://cossc.gsfc.nasa.gov/docs/cgro/index.html ] from April 1991 to June 2000. Then, the most sensitive instrument of its kind, even EGRET could not see the quiet Sun which is extremely faint at gamma-ray energies. So why [ http://www.aas.org/publications/baas/v28n4/aas189/abs/ S025002.html ] is the Moon bright? High energy charged particles, known as cosmic rays [ http://imagine.gsfc.nasa.gov/docs/features/topics/snr_group/ cosmic_rays.html ], constantly bombard the unprotected lunar surface generating gamma-ray photons. EGRET's gamma-ray vision [ http://cossc.gsfc.nasa.gov/docs/cgro/epo/vu/ index.html ] was not sharp enough to resolve a lunar disk or any surface features, but its sensitivity reveals the induced gamma-ray [ http://antwrp.gsfc.nasa.gov/apod/ap050331.html ] moonglow. So far unique [ http://glast.gsfc.nasa.gov/ ], the image was generated from eight exposures made during 1991-1994 and covers a roughly 40 degree wide field of view with gamma-ray intensity represented in false color.
GLAST Gamma Ray Sky Simulati
…
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.
GLAST Arrives
Tucked inside a shipping con
…
6/3/08
Description
Tucked inside a shipping container, NASA's Gamma-ray Large Area Space Telescope arrives by truck at Kennedy Space Center in Florida, where the spacecraft will under go final preparations before launch. GLAST will launch aboard a Delta II rocket from Launch Pad 17-B on Cape Canaveral Air Force Station. </br></br> Photo credit: NASA/Kim Shiflett</br> March 4, 2008
Date
6/3/08
GLAST Launches From Kennedy
…
Spacecraft begins mission to
…
Description
Spacecraft begins mission to study gamma rays.
A Mystery In Gamma Rays
Title
A Mystery In Gamma Rays
Explanation
Gamma rays [ http://cossc.gsfc.nasa.gov/cossc/outreach/nasm/VU/ ] are the most energetic form of light, packing a million or more times the energy of visible light photons. What if you could see [ http://cossc.gsfc.nasa.gov/cossc/outreach/images/ ] gamma rays? If you could, the familiar skyscape [ http://antwrp.gsfc.nasa.gov/apod/ap990410.html ] of steady stars would be replaced [ http://antwrp.gsfc.nasa.gov/apod/ap980321.html ] by some of the most bizarre objects known [ http://www.skypub.com/tips/basics/dsonames.html ] to modern astrophysics [ http://ads.harvard.edu/ ] -- and some which are "unknown". When the EGRET [ http://lheawww.gsfc.nasa.gov/docs/gamcosray/EGRET/ instrument_description.html ] instrument on the orbiting Compton Gamma-ray Observatory [ http://antwrp.gsfc.nasa.gov/apod/ap000116.html ] surveyed the sky in the 1990s, it cataloged 271 celestial sources [ http://cossc.gsfc.nasa.gov/cossc/descriptions/ egret_src.html ] of high-energy gamma-rays. These sources are very different from the powerful gamma-ray bursters [ http://antwrp.gsfc.nasa.gov/apod/ap991104.html ] that flash and fade rapidly from view, and researchers identified some with exotic black holes [ http://antwrp.gsfc.nasa.gov/apod/ap980729.html ], neutron stars [ http://cossc.gsfc.nasa.gov/cossc/outreach/descriptions/ egret_pulsars.html ], and distant flaring galaxies [ http://antwrp.gsfc.nasa.gov/apod/ap981226.html ]. But 170 of the cataloged sources, shown in the above all-sky [ http://antwrp.gsfc.nasa.gov/apod/ap980523.html ] map, remain unidentified. Many sources [ http://pao.gsfc.nasa.gov/gsfc/spacesci/structure/cgro.htm ] in this gamma-ray mystery map likely belong to the already known classes of gamma-ray emitters and are simply obscured or too faint to be otherwise positively identified. However, astronomers recently called attention [ http://pao.gsfc.nasa.gov/gsfc/spacesci/structure/cgro.htm#press ] to the ribbon of sources winding through the plane of the galaxy, projected here along the middle of the map, which may represent a large unknown class of galactic gamma-ray emitters. In any event, the unidentified sources could remain a mystery until the planned launch of the more sensitive Gamma-ray Large Area Space Telescope [ http://www-glast.sonoma.edu/ ] in 2005.
Installation of Chandra X-Ra
…
Name of Image
Installation of Chandra X-Ray Observatory Charged-Coupled Imaging Spectrometer
Date of Image
1997-04-15
Full Description
This photograph captures the installation of the Chandra X-Ray Observatory, formerly Advanced X-Ray Astrophysics Facility (AXAF), Advanced Charged-Coupled Device (CCD) Imaging Spectrometer (ACIS) into the Vacuum Chamber at the X-Ray Calibration Facility (XRCF) at Marshall Space Flight Center (MSFC). The AXAF was renamed Chandra X-Ray Observatory (CXO) in 1999. The CXO is the most sophisticated and the world's most powerful x-ray telescope ever built. It observes x-rays from high-energy regions of the universe, such as hot gas in the remnants of exploded stars. The ACIS is one of two focal plane instruments. As the name suggests, this instrument is an array of CCDs similar to those used in a camcorder. This instrument will be especially useful because it can make x-ray images and measure the energies of incoming x-rays. It is the instrument of choice for studying the temperature variation across x-ray sources, such as vast clouds of hot-gas intergalactic space. MSFC's XRCF is the world's largest, most advanced laboratory for simulating x-ray emissions from distant celestial objects. It produces a space-like environment in which components related to x-ray telescope imaging are tested and the quality of their performances in space is predicted. TRW, Inc. was the prime contractor for the development of the CXO and NASA's MSFC was responsible for its project management. The Smithsonian Astrophysical Observatory controls science and flight operations of the CXO for NASA from Cambridge, Massachusetts. The CXO was launched July 22, 1999 aboard the Space Shuttle Columbia (STS-93).
Chandra X-Ray Observatory Im
…
Name of Image
Chandra X-Ray Observatory Image of Black Hole
Date of Image
2000-04-01
Full Description
This Chandra X-Ray Observatory (CXO) image is a spectrum of a black hole, which is similar to the colorful spectrum of sunlight produced by a prism. The x-rays of interest are shown here recorded in bright stripes that run rightward and leftward from the center of the image. These x-rays are sorted precisely according to their energy with the highest-energy x-rays near the center of the image and the lower-energy x-rays farther out. The spectrum was obtained by using the Low Energy Transmission Grating (LETG), which intercepts x-rays and changes their direction by the amounts that depend sensitively on the x-ray energy. The assembly holds 540 gold transmission gratings. When in place behind the mirrors, the gratings intercept the x-rays reflected from the telescope. The bright spot at the center is due to a fraction of the x-ray radiation that is not deflected by the LETG. The spokes that intersect the central spot and the faint diagonal rays that flank the spectrum itself are artifacts due to the structure that supports the LETG grating elements. (Photo credit: NASA Cfa/J. McClintock et al)
The X-Ray Moon Credit: DARA,
…
Title
The X-Ray Moon Credit: DARA, ESA [ http://www.esrin.esa.it/ ], MPE [ http://www.mpe-garching.mpg.de/ ], NASA [ http://www.nasa.gov/ ], J.H.M.M. Schmitt
Explanation
This X-Ray [ http://antwrp.gsfc.nasa.gov/apod/lib/glossary.html#X-ray ] image of the Moon [ http://antwrp.gsfc.nasa.gov/apod/ap960919.html ] was made by the orbiting Roentgen Observatory Satellite (ROSAT [ http://heasarc.gsfc.nasa.gov/docs/heasarc/missions/rosat.html ]) in 1990. It shows three distinct regions: a bright X-ray sky, a bright part of the Moon, and a relatively dark part of the Moon. The bright X-ray sky is due to the diffuse cosmic X-ray background [ http://www.rosat.mpe-garching.mpg.de/survey/sxrb/ ]. The bright lunar crescent shines because it reflects X-rays emitted by the Sun [ http://antwrp.gsfc.nasa.gov/apod/ap960727.html ]. The dark lunar face is in shadow and so stands stands out from the relatively bright background - but, surprisingly it is not completely dark! Where do those X-rays from? They are currently thought to result from energetic particles from the solar wind [ http://www-spof.gsfc.nasa.gov/Education/Intro.html ] bombarding the lunar surface.
X-ray Moon and X-ray Star
Title
X-ray Moon and X-ray Star
Explanation
An X-ray star winks out behind the Moon in these before and after views of a lunar occultation [ http://www.sky.net/~robinson/iotandx.htm ] of the galactic X-ray source designated GX5-1 [ http://heasarc.gsfc.nasa.gov/Images/rosat/rosat18.html ]. The false color images were made using data from the ROSAT orbiting observatory [ http://heasarc.gsfc.nasa.gov/docs/rosat/rosat3.html ] and show high energy X-rays in yellow (mostly from GX5-1), and lower energy X-rays in red (the Moon reflecting X-rays from the Sun [ http://antwrp.gsfc.nasa.gov/apod/ap951004.html ]). GX5-1 is a binary system [ http://heasarc.gsfc.nasa.gov/docs/binary.html ] consisting of a neutron star [ http://antwrp.gsfc.nasa.gov/apod/lib/glossary.html#ns ] and a companion star in mutual orbit about the system's center of mass. The gas in the companion star's outer envelope falls toward the neutron star and accumulates in a disk [ http://antwrp.gsfc.nasa.gov/apod/ap951226.html ] around it. This disk material swirls deeper in to the neutron star's gravitational well [ http://antwrp.gsfc.nasa.gov/htmltest/rjn_bht.html ], and is finally dumped onto its surface - in the process creating tremendous temperatures and generating the high energy X-rays.
X-Ray Moon
Title
X-Ray Moon
Explanation
This x-ray image [ http://heasarc.gsfc.nasa.gov/docs/rosat/gallery/ misc_moon2.html ] of the Moon [ http://antwrp.gsfc.nasa.gov/apod/ap960919.html ] was made by the orbiting ROSAT [ http://heasarc.gsfc.nasa.gov/docs/rosat/rhp_geninfo.html ] (Röntgensatellit [ http://heasarc.gsfc.nasa.gov/docs/rosat/gallery/ wilhelm.html ]) Observatory in 1990. In this digital picture, pixel brightness corresponds to x-ray intensity. Consider the image in three parts: the bright hemisphere of the x-ray moon, the darker half of the moon, and the x-ray sky [ http://antwrp.gsfc.nasa.gov/apod/ap000819.html ] background. The bright lunar hemisphere shines in x-rays [ http://imagine.gsfc.nasa.gov/docs/science/know_l1/ history1_xray.html ] because it reflects x-rays emitted by the sun ... just as it shines at night [ http://antwrp.gsfc.nasa.gov/apod/ap000113.html ] by reflecting visible sunlight. The background [ http://heasarc.gsfc.nasa.gov/docs/objects/ background/background.html ] sky has an x-ray glow in part due to the myriad of distant, powerful active galaxies, unresolved in the ROSAT picture but recently detected in Chandra Observatory x-ray images [ http://antwrp.gsfc.nasa.gov/apod/ap000114.html ]. But why isn't the dark half of the moon completely dark? It's true that the dark lunar face is in shadow [ http://antwrp.gsfc.nasa.gov/apod/ap980312.html ] and so is not reflecting solar x-rays [ http://antwrp.gsfc.nasa.gov/apod/ap981221.html ]. Still, the few x-ray photons which seem to come from the moon's dark half are currently thought to be caused by energetic particles in the solar wind [ http://www-spof.gsfc.nasa.gov/Education/wsolwind.html ] bombarding the lunar surface.
Chandra X-ray Images of Eart
…
Name
Chandra X-ray Images of Earth Aurora on Jan 24, 30, Feb 15 & Apr 13, 2004
A Sequence of Soft X-Ray Pho
…
Name of Image
A Sequence of Soft X-Ray Photographs of the Sun
Date of Image
1973-01-01
Full Description
This montage is a sequence of soft x-ray photographs of the boot-shaped coronal hole rotating with the sun. The individual pictures were taken about 2 days apart by the Skylab telescope. Most of the apparent changes in this 6-day period resulted from a changing perspective. Skylab data helped demonstrate that coronal holes are sources of high-velocity streams in the solar wind. These high-velocity streams can be electrons, protons, and atomic nuclei that spray out from the Sun into interplanetary space. When the coronal hole is near the center of the Sun, as in view 2, the sprinkler is directed at Earth. These high-speed streams of solar wind distort Earth's magnetic field and disturb it's upper atmosphere.
X-ray Transit Of Mercury
Title
X-ray Transit Of Mercury
Explanation
This sequence of [ http://www.solar.isas.ac.jp/sxt_co/980626.html ] false color X-ray images captures a rare event - the passage [ http://www.arrakis.es/~xgarciaf/paso.htm ] or transit of [ http://www.dsellers.demon.co.uk/venus/ven_ch4.htm ] planet Mercury in front of the Sun. Mercury's small disk [ http://www.seds.org/nineplanets/nineplanets/mercury.html ] is silhouetted against the bright background of X-rays from the hot Solar Corona [ http://antwrp.gsfc.nasa.gov/apod/ap970217.html ]. It appears just to the right of center in the top frame and moves farther right as the sequence progresses toward the bottom. The dark notch is a coronal hole near the Solar South Pole [ http://ulysses.jpl.nasa.gov/ ], while a flaring coronal bright point can be seen to the left of the notch in the top frames. The frames were recorded [ http://www.lmsal.com/SXT/html2/Mercury_Transit_of_Solar_Corona.html ] on November 6, 1993 by the Soft X-ray Telescope [ http://www.lmsal.com/SXT/homepage.html ] on board the orbiting Yohkoh satellite [ http://www.lmsal.com/cgi-bin/yopos ]. Transits of Mercury (and Venus) were historically used to discover the geometry of the solar system [ http://beast.as.arizona.edu/textbook/text/CH03.html ] and to map planet Earth [ http://pacific.vita.org/pacific/cook/ ] itself.
Polishing X-ray Mirror Mandr
…
Name of Image
Polishing X-ray Mirror Mandrel
Date of Image
1999-04-01
Full Description
NASA's Space Optics Manufacturing Center has been working to expand our view of the universe via sophisticated new telescopes. The Optics Center's goal is to develop low-cost, advanced space optics technologies for the NASA program in the 21st century - including the long-term goal of imaging Earth-like planets in distant solar systems. To reduce the cost of mirror fabrication, Marshall Space Flight Center (MSFC) has developed replication techniques, the machinery, and materials to replicate electro-formed nickel mirrors. The process allows fabricating precisely shaped mandrels to be used and reused as masters for replicating high-quality mirrors. MSFC's Space Optics Manufacturing Technology Center (SOMTC) has grinding and polishing equipment ranging from conventional spindles to custom-designed polishers. These capabilities allow us to grind precisely and polish a variety of optical devices, including x-ray mirror mandrels. This image shows Charlie Griffith polishing the half-meter mandrel at SOMTC.
Inspection of the Replicated
…
Name of Image
Inspection of the Replicated X-ray Mirror Mandrel
Date of Image
1999-04-01
Full Description
NASA's Space Optics Manufacturing Center has been working to expand our view of the universe via sophisticated new telescopes. The Optics Center's goal is to develop low-cost, advanced space optics technologies to the NASA program in the 21st century - including the long-term goal of imaging Earth-like planets in distant solar systems. To reduce the cost of mirror fabrication, Marshall Space Flight Center (MSFC) has developed replication techniques, the machinery, and materials to replicate electro-formed nickel mirrors. The process allows fabricating precisely shaped mandrels to be used and reused as masters for replicating high-quality mirrors. Photograph shows J.R. Griffith inspecting a replicated x-ray mirror mandrel.
Space Optic Manufacturing -
…
Name of Image
Space Optic Manufacturing - X-ray Mirror
Date of Image
1998-08-31
Full Description
NASA's Space Optics Manufacturing Center has been working to expand our view of the universe via sophisticated new telescopes. The Optics Center's goal is to develop low-cost, advanced space optics technologies for the NASA program in the 21st century - including the long-term goal of imaging Earth-like planets in distant solar systems. To reduce the cost of mirror fabrication, Marshall Space Flight Center (MSFC) has developed replication techniques, the machinery and materials to replicate electro-formed nickel mirrors. The process allows fabricating precisely shaped mandrels to be used and reused as masters for replicating high-quality mirrors. This image shows a lightweight replicated x-ray mirror with gold coatings applied.
ROSAT Explores The X-Ray Sky
Title
ROSAT Explores The X-Ray Sky
Explanation
Launched in 1990, the orbiting ROSAT observatory [ http://heasarc.gsfc.nasa.gov/docs/rosat/rosat.html ] explored the Universe by viewing the entire sky in x-rays [ http://imagine.gsfc.nasa.gov/docs/science/know_l1/ history1_xray.html ] -- photons with about 1,000 times more energy than visible light. This ROSAT survey [ http://www.xray.mpe.mpg.de/rosat/survey/sxrb/12/ass.html ] produced the sharpest, most sensitive image of the x-ray sky to date. The all-sky image is shown with the plane of our Milky Way Galaxy [ http://antwrp.gsfc.nasa.gov/apod/ap980523.html ] running horizontally through the center. Both x-ray brightness and relative energy are represented with red, green, and blue colors indicating three x-ray energy ranges (from lowest to highest). Bright x-ray spots near the galactic plane are within our own Milky Way. The brightest region (right of center) is toward the Vela Pulsar [ http://antwrp.gsfc.nasa.gov/apod/ap000609.html ] and the Puppis supernova remnant [ http://antwrp.gsfc.nasa.gov/apod/ap991209.html ]. Bright sources beyond our Galaxy are also apparent, notably the Virgo cluster of galaxies [ http://www.seds.org/messier/more/virgo.html ] (near top right) and the Large Magellanic Cloud (LMC) [ http://www.seds.org/messier/xtra/ngc/lmc.html ]. The LMC is easy to find here as several of the black stripes (blank areas caused by missing data) seem to converge on its position (lower right). Over large areas of the sky a general diffuse background of x-rays [ http://chandra.harvard.edu/press/00_releases/ press_011400bg.html ] dominates. Hot gas in our own Galaxy provides much of this background and gives rise to the grand looping structures [ http://antwrp.gsfc.nasa.gov/apod/ap990503.html ] visible in the direction of the galactic center (image center). Unresolved extragalactic sources also add to this background, particularly above and below the plane. Despite the x-ray sky's exotic appearance, a very familiar feature is visible - the gas and dust clouds which line the plane of our galaxy absorb x-rays as well as optical light and produce the dark bands running through the galactic center [ http://antwrp.gsfc.nasa.gov/apod/ap000629.html ].
The X-Ray Sky
Title
The X-Ray Sky
Explanation
What if you could see X-rays [ http://antwrp.gsfc.nasa.gov/apod/lib/glossary.html#X-ray ]? If you could, the night sky [ http://antwrp.gsfc.nasa.gov/htmltest/jbonnell/www/multiw_sky.html ] would be a strange and unfamiliar place. X-rays are about 1,000 times more energetic than visible light photons and are produced in violent and high temperature astrophysical environments. Instead of the familiar steady stars, the sky would seem to be filled with exotic binary star systems [ http://antwrp.gsfc.nasa.gov/apod/ap951226.html ] composed of white dwarfs [ http://antwrp.gsfc.nasa.gov/apod/ap950910.html ], neutron stars [ http://antwrp.gsfc.nasa.gov/apod/ap951122.html ], and black holes [ http://antwrp.gsfc.nasa.gov/apod/ap951127.html ], along with flare stars, X-ray bursters, pulsars [ http://pulsar.princeton.edu/rpr.shtml ], supernova remnants [ http://antwrp.gsfc.nasa.gov/apod/ap951203.html ] and active galaxies [ http://antwrp.gsfc.nasa.gov/apod/ap951022.html ]. This X-ray image of the entire sky was constructed with Skyview [ http://skyview.gsfc.nasa.gov ], using data from the first High Energy Astronomy Observatory (HEAO 1) [ http://heasarc.gsfc.nasa.gov/docs/heao1/ heao1a2_gifbrowser.html ], and plotted in a coordinate system centered on the galactic center with the north galactic pole at the top. Sources near the galactic center are seen to dominate in this false color map which shows regions of highest X-ray intensity in yellow. Astronomers' ability to observe the sky at X-ray energies will be greatly enhanced by the recently launched X-ray Timing Explorer (XTE [ http://heasarc.gsfc.nasa.gov/docs/ xte/xte_1st.html ]) satellite.
The Cosmic X-Ray Background
Title
The Cosmic X-Ray Background
Explanation
Early on, x-ray satellites [ http://heasarc.gsfc.nasa.gov/docs/corp/ observatories.html ] revealed a surprising cosmic background [ http://chandra.harvard.edu/xray_sources/ background.html ] glow of x-rays and astronomers have struggled to understand its origin. Now, peering through [ http://sci.esa.int/content/news/ index.cfm?aid=23&cid=45&oid=25139 ] a hole in the obscuring gas and dust of our own Milky Way Galaxy, the powerful orbiting XMM-Newton telescope [ http://antwrp.gsfc.nasa.gov/apod/ap991221.html ] has recorded this deep image of the x-ray sky [ http://antwrp.gsfc.nasa.gov/apod/ap000819.html ], resolving some of the mysterious background [ http://antwrp.gsfc.nasa.gov/apod/ap000114.html ] into many faint individual sources. The tantalizing image [ http://sci.esa.int/content/searchimage/ searchresult.cfm?aid=23&cid=45&ooid=25141 ] is color-coded, with red representing relatively low energy x-rays, photons with 500 or so times the energy of visible light. Green and blue colors correspond to increasingly energetic x-rays with up to about 10,000 times visible light energies. Notably, the faint sources tend to be green and blue, showing x-ray characteristics of huge amounts of material falling into massive black holes in very distant galaxies. Do massive black holes [ http://oposite.stsci.edu/pubinfo/PR/2000/22/ index.html ] reside in the hearts of all large galaxies? The XMM-Newton results add [ http://arxiv.org/abs/astro-ph/0011271 ] to the growing consensus that they do and that, from across the universe [ http://universe.gsfc.nasa.gov/ ], x-rays produced as matter feeds these black holes account for [ http://xxx.lanl.gov/abs/astro-ph/0008019 ] the cosmic x-ray background.
Solstice Sun In Soft X-rays
Title
Solstice Sun In Soft X-rays
Explanation
The solstice occurs today at 8:56 PM Eastern Standard Time. At the solstice the sun reaches [ http://www.nsta.org/programs/sst/aws/Default.htm ] its most southerly position in the sky [ http://www.archaeoastronomy.com/index.html ] and winter begins for the Northern Hemisphere while summer starts South of the Equator. This false-color image of the sun was made [ http://www.lmsal.com/YPOP/ProjectionRoom/latest.html ] about 48 hours before the solstice in the light of soft (lower energy) X-rays by a telescope on board the space-based Yohkho solar observatory [ http://www.solar.isas.ac.jp/english/index.html ]. The normally bright, visible solar surface or photosphere appears dark in X-ray light while active regions in the solar corona [ http://www.lmsal.com/YPOP/Spotlight/Tour/active2.html ] which lie above the photosphere are particularly X-ray bright. Solar photospheric temperatures are about 6,000 degrees C. but the X-ray bright coronal regions have temperatures of millions of degrees. Why is the sun's corona so hot [ http://www.lmsal.com/YPOP/Spotlight/Tour/tour05.html ]?
Gamma Ray Observatory (GRO)
…
Title
Gamma Ray Observatory (GRO) in ground support structure at TRW
Description
The Gamma Ray Observatory (GRO) is positioned in a support structure in TRW's assembly room for checkout and processing prior to shipment to the Kennedy Space Center (KSC). GRO is the heaviest NASA science satellite ever to be deployed by the Space Shuttle into low Earth orbit. GRO's trunnions are locked into the support structure. From left to right are three of the four GRO instruments including the Oriented Scintillation Spectrometer Experiment (OSSE), the Imaging Compton Telescope (COMPTEL), and the Energetic Gamma Ray Experiment Telescope (EGRET). The Burst and Transient Source Experiment (BATSE) equipment is located on GRO's corners. GRO, which weighs just over 35,000 pounds (15,876 kilograms), is a space-based observatory scheduled to be put into space by Atlantis, Orbiter Vehicle (OV) 104, next year. GRO is designed to study the universe in an invisible, high-energy form of light known as gamma rays. Gamma rays, which cannot penetrate the Earth's atmosphere, are of interest to
Date Taken
1990-06-13
STS-37 Gamma Ray Observatory
…
Title
STS-37 Gamma Ray Observatory (GRO) at KSC Payload Hazardous Servicing Fac
Description
Kennedy Space Center (KSC) workers at the Payload Hazardous Servicing Facility are removing the Gamma Ray Observatory (GRO) from its storage container. GRO, one of four NASA Great Observatories, arrived at KSC on 02-06-90 from the California plant of builder TRW. Weighing a massive 34,700 pounds, GRO will be the heaviest payload without an upper stage ever carried aboard the Space Shuttle. It is scheduled for deployment from Atlantis, Orbiter Vehicle (OV) 104, during STS-37.
Date Taken
1990-05-07
STS-37 Gamma Ray Observatory
…
Title
STS-37 Gamma Ray Observatory (GRO) held by RMS over OV-104's payload bay
Description
The Gamma Ray Observatory (GRO) with its solar array (SA) panels deployed is grappled by the remote manipulator system (RMS) and held over Atlantis', Orbiter Vehicle (OV) 104's, payload bay (PLB) during systems checkout. GRO's four complement instruments are visible: the Energetic Gamma Ray Experiment Telescope (EGRET) (at the bottom), the Imaging Compton Telescope (COMPTEL) (center), the Oriented Scintillation Spectrometer Experiment (OSSE) (top), and Burst and Transient Source Experiment (BATSE) (on four corners). This view taken by the STS-37 crew shows the GRO backdropped against clouds over water on the Earth's surface.
Date Taken
1991-04-11
Artist concept - Gamma Ray O
…
Title
Artist concept - Gamma Ray Observatory (GRO) orbits Earth after STS-37 deploy
Description
Artist concept shows Gamma Ray Observatory (GRO) orbiting Earth after STS-37 deployment. The high gain antenna (HGA) and solar array (SA) panels are deployed. The four complement instruments are visible including: the Burst and Transient Source Experiment (BATSE) (at the four corners of the satellite), the Oriented Scintillation Spectrometer Experiment (OSSE) (left), the Imaging Compton Telescope (COMPTEL) (center), and the Energetic Gamma Ray Experiment Telescope (EGRET) (right).
Date Taken
1990-03-01
HETE-2 Rides Pegasus
Title
HETE-2 Rides Pegasus
Explanation
The Stargazer [ http://www.orbital.com/LaunchVehicles/Pegasus/stargazer.htm ], a modified Lockheed L-1011 aircraft, soared into the skies above Kwajalein [ http://www.smdc.army.mil/kmr.html ] Atoll in the pacific on October 9th. A small satellite observatory known as the High Energy Transient Explorer - 2 (HETE-2 [ http://space.mit.edu/HETE/ ]) was tucked into Stargazer's winged Pegasus rocket [ http://www.orbital.com/LaunchVehicles/Pegasus/pegasus.htm ], slung beneath the large trimotor jet's fuselage. Dropped [ http://science.ksc.nasa.gov/payload/missions/hete-2/ ] from its mother ship, the Pegasus then successfully flew HETE-2 into orbit. HETE-2's [ http://space.mit.edu/HETE/spacecraft.html ] mission is to hunt gamma-ray bursts, brief, random flashes of high energy photons from the distant cosmos. Gamma-ray bursts [ http://science.nasa.gov/newhome/headlines/ ast26mar99_1.htm ] are impressive, believed to be the most powerful explosions in the Universe, but so few have been well located and studied that the nature of [ http://xxx.lanl.gov/abs/astro-ph/0010176 ] the bursters themselves is still shrouded in mystery. HETE-2's x-ray and gamma-ray instruments will be able to rapidly alert ground-based observatories to point toward ongoing, bright gamma-ray bursts. Communications antennae and solar panels neatly folded, HETE-2 is seen [ http://space.mit.edu/HETE/pictures/ ] here being carefully enclosed in the Pegasus nose fairing.
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![The X-Ray Moon Credit: DARA, ESA [ http://www.esrin.esa.it/ ], MPE [ http://www.mpe-garching.mpg.de/ ], NASA [ http://www.nasa.gov/ ], J.H.M.M. Schmitt](http://mm04.nasaimages.org/MediaManager/srvr?mediafile=/Size1/NVA2-4-NA/8085/moon_rosat.jpg&userid=1&username=admin&resolution=1&servertype=JVA&cid=4&iid=NVA2&vcid=NA&usergroup=NASA_Astronomy_Picture_of_the_Day_Collecti-4-Admin&profileid=16)
