1999 Images

1999 Spacepics: Please note that images are chronicled by date - most recent listed first.

ON THE DAY THE SOLAR WIND DISAPPEARED,
SCIENTISTS SAMPLE PARTICLES DIRECTLY
FROM THE SUN

From May 10-12, 1999, the solar wind that blows constantly from the Sun virtually disappeared -- the most drastic and longest-lasting decrease ever observed.

Dropping to a fraction of its normal density and to half its normal speed, the solar wind died down enough to allow physicists to observe particles flowing directly from the Sun's corona to Earth. This severe change in the solar wind also changed the shape of Earth's magnetic field and produced an unusual auroral display at the North Pole.

Data visualization of the X ray emissions over the North Pole during the "polar rain" of electrons on May 11, 1999. The emissions were detected by the PIXIE instrument on NASA's Polar spacecraft.

GSFC Press Release 99-145
EDITOR'S NOTE: Images, movies, captions, and more detailed background information associated with this release are available on the Internet at:

http://www-spof.gsfc.nasa.gov/istp/news/9912

13 December 1999

Data from Goddard's Mars Orbiter Laser Altimeter (MOLA) played a key role in helping scientists determine the primary landing site for the Mars Polar Lander. Engineers are aiming for a 200 kilometers (125 miles) long and 20 kilometers (12-1/2 miles) wide strip of gentle, rolling plains.  Launched on January 3, 1999, Mars Polar Lander will study the soil and look for ice beneath the surface of the Martian south pole.

Landing Site Preview

Scientists used data from MOLA to learn about elevation changes within the primary landing site (marked with an oval.) Colors in the inset image correspond to changes in elevation. White colors indicate elevations in excess of 3012 meters, red shows elevations between 2500m - 3012m, yellow shows elevations 2450m - 2500m, dark cyan shows elevations 2150m-2450m, dark violet shows elevations from 320m - 2150m. The topography in these images is vertically exaggerated by a factor of 5.

More information visit our Mars page

02 December 1999

  Image Credit: NASA and The Hubble Heritage Team (STScI)

02 December 1999

This troupe of four galaxies, known as Hickson Compact Group 87 (HCG 87), is performing an intricate dance orchestrated by the mutual gravitational forces acting between them. The dance is a slow, graceful minuet, occurring over a time span of hundreds of millions of years.

The Wide Field and Planetary Camera 2 on NASA's Hubble Space Telescope (HST) provides a striking improvement in resolution over previous ground-based imaging. In particular, this image reveals complex details in the dust lanes of the group's largest galaxy member (HCG 87a), which is actually disk-shaped, but tilted so that we see it nearly edge-on. Both 87a and its elliptically shaped nearest neighbor (87b) have active galactic nuclei which are believed to harbor black holes that are consuming gas.

HCG 87 was selected for Hubble imaging by members of the public who visited the Hubble Heritage website (http://heritage.stsci.edu) during the month of May and registered their votes. The HST exposures of the winning target were then acquired in July 1999 by the Hubble Heritage Team and guest astronomers Sally Hunsberger (Lowell Observatory, Flagstaff, Arizona) and Jane Charlton (Pennsylvania State University).

Image Credit: The Hubble Heritage Team (AURA/STScI/NASA).

NOTE TO EDITORS: For additional information, please contact Lisa Frattare, STScI, 3700 San Martin Drive, Baltimore, MD 21218, (phone) 410-338-4724, (fax) 410-338-4579, (e-mail) frattare@stsci.edu.

Image files are available on the Internet at:

http://heritage.stsci.edu/

http://oposite.stsci.edu/pubinfo/pr/1999/31 or via links in

http://oposite.stsci.edu/pubinfo/latest.html and

http://oposite.stsci.edu/pubinfo/pictures.html

Higher resolution digital versions (300 dpi JPEG and TIFF)

are available at:

http://oposite.stsci.edu/pubinfo/pr/1999/31/pr-photos.html

02 September 1999

NASA SELECTS MINIATURE SPACECRAFT TO TEST SPACE TECHNOLOGY

They're each about the size of a large birthday cake, weigh about as much as a desktop computer, and are smart enough to fly in formation far from Earth while they test new technologies. They are three very small satellites, called the Nanosat Constellation Trailblazer mission, and today NASA selected them as the agency's latest New Millennium mission. The mission will validate methods of operating several spacecraft as a system, and test eight technologies in the harsh space environment near the boundary of Earth's protective magnetic field, or magnetosphere.

HQ Press Release 99-095

19 August 1999

MATTER'S FINAL PLUNGE ON BLACK HOLE ROLLER COASTER DETECTED

The final cry from material streaming toward a black hole at more than 6 million miles per hour -- possibly the first evidence of matter actually falling into a black hole -- was detected by scientists at NASA's Goddard Space Flight Center in Greenbelt, Md. This is distinct from the readily observed phenomena of matter swirling around or away from a black hole. The result, gathered from the evidence of X-ray signatures from hot gas in a galaxy 100 million light years away, appears in an upcoming article in Astrophysical Journal Letters.

Resembling a gigantic hubcap in space, a 3,700 light-year-diameter dust disk encircles a 300 million solar-mass black hole in the center of the elliptical galaxy NGC 7052.

GSFC Press Release 99-089

Related Links:

Information about black holes is at:
http://imagine.gsfc.nasa.gov/docs/introduction/black_holes.html

More pictures and info is at:
http://antwrp.gsfc.nasa.gov/htmltest/rjn_bht.html

The Hubble Space Telescope photographed gas and dust swirling around a massive black hole in a nearby galaxy:
http://oposite.stsci.edu/pubinfo/pr/1998/22/

16 August 1999

Eclipse 99

On Wednesday, August 11, 1999, a total eclipse of the Sun will be visible from within a narrow corridor that traverses the Eastern Hemisphere. The path of the Moon's umbral shadow begins in the Atlantic and crosses Central Europe, the Middle East, and India where it ends at sunset in the Bay of Bengal. A partial eclipse will be seen within the much broader path of the Moon's penumbral shadow, which includes Northeastern North America, all of Europe, Northern Africa and the western half of Asia. This event is the last total solar eclipse of the 20th century, and it will benefit formal and informal education communities alike.

Eclipse 99 Website - fact-filled website on this eclipse, a history of eclipses and future eclipses.  Visit this site for images and movies from the Aug. 11 Eclipse.

11 August 1999

Caption

STIFF SOLAR ATMOSPHERE CANCELS DANCE AND GETS HOT

Coronal loops, immense coils of hot gas on the surface of the Sun, vibrate wildly after the blast wave from a solar flare hits them. However, their dance is quickly squelched by resistance from the Sun's outer atmosphere (corona). The corona restricts motion due to internal friction hundreds of millions of times greater than expected, according to recent observations from NASA's Transition Region and Coronal Explorer (TRACE) spacecraft.

GSFC Press Release 99-088

05 August 1999

A huge, billowing pair of gas and dust clouds are captured in this stunning NASA Hubble Space Telescope image of the supermassive star Eta Carinae.

Using a combination of image processing techniques (dithering, subsampling and deconvolution), astronomers created one of the highest resolution images of an extended object ever produced by Hubble Space Telescope. The resulting picture reveals astonishing detail.

Even though Eta Carinae is more than 8,000 light-years away, structures only 10 billion miles across (about the diameter of our solar system) can be distinguished. Dust lanes, tiny condensations, and strange radial streaks all appear with unprecedented clarity.

Eta Carinae was observed by Hubble in September 1995 with the Wide Field Planetary Camera 2 (WFPC2). Images taken through red and near-ultraviolet filters were subsequently combined to produce the color image shown. A sequence of eight exposures was necessary to cover the object's huge dynamic range: the outer ejecta blobs are 100,000 times fainter than the brilliant central star.

Eta Carinae was the site of a giant outburst about 150 years ago, when it became one of the brightest stars in the southern sky. Though the star released as much visible light as a supernova explosion, it survived the outburst. Somehow, the explosion produced two polar lobes and a large thin equatorial disk, all moving outward at about 1.5 million miles per hour.

The new observation shows that excess violet light escapes along the equatorial plane between the bipolar lobes. Apparently there is relatively little dusty debris between the lobes down by the star; most of the blue light is able to escape. The lobes, on the other hand, contain large amounts of dust which preferentially absorb blue light, causing the lobes to appear reddish.

Estimated to be 100 times more massive than our Sun, Eta Carinae may be one of the most massive stars in our Galaxy. It radiates about five million times more power than our Sun. The star remains one of the great mysteries of stellar astronomy, and the new Hubble images raise further puzzles. Eventually, this star's outburst may provide unique clues to other, more modest stellar bipolar explosions and to hydrodynamic flows from stars in general.

Photo Credit: Jon Morse (University of Colorado), and

NASA Investigating Team: Kris Davidson (University of Minnesota), Bruce Balick (University of Washington), Dennis Ebbets (Ball Aerospace), Adam Frank (University of Minnesota), Fred Hamann (University of California - San Diego), Roberta Humphreys (University of Minnesota), Sveneric Johansson (Lund Observatory), Jon Morse (University of Colorado), Nolan Walborn (Space Telescope Science Institute), Gerd Weigelt (Max Planck Inst. for Radio Astronomy, Bonn), and Richard White (Space Telescope Science Institute)

Image files in GIF and JPEG format and captions may be accessed on Internet via anonymous ftp from oposite.stsci.edu in /pubinfo.

GIF JPEG PRC96-23a Eta Carinae color gif/EtaCarC.gif jpeg/EtaCarC.jpg Higher resolution digital versions (300dpi JPEG) of the release photographs will be available temporarily in /pubinfo/hrtemp: 96-23a.jpg (color), 96-23abw.jpg (black/white).

GIF and JPEG images, captions and press release text are available via World Wide Web at: http://www.stsci.edu/pubinfo/PR/96/23.html   and via links in: http://www.stsci.edu/pubinfo/latest.html   or http://www.stsci.edu/pubinfo/pictures.html .

GSFC Press Release
Images and Captions

ETA CARINAE SPECTRA

These are spectra of light emitted by hydrogen atoms in Eta Carinae and its surrounding nebula. The spectra were taken by the Space Telescope Imaging Spectrograph (STIS) instrument on board the Hubble Space Telescope. A spectrograph separates light into its component colors, which correspond to different wavelengths. This is similar to the way a prism separates white light into a rainbow of distinct colors. By analyzing light this way, astronomers learn a great deal about the object emitting the light, such as its temperature, chemical composition, and motion. The light used by STIS for this graph corresponds to hydrogen alpha emission, which appears red to the human eye.

The spectra are from different times during the star's recent doubling of brightness; December 1997 (top left), November 1998 (top right), March 1998 (bottom left), February 1999 (bottom right). The horizontal axis of each spectrum displays the wavelength, or color, of the light. Shorter wavelengths (more blue) are on the left and longer wavelengths (more red) are on the right. The vertical axis measures the brightness (intensity) of the light. The diagonal axis is the area around Eta Carinae imaged by STIS. The peak is light from Eta Carinae, and smaller peaks in the foreground are light from the surrounding nebula.

A wide "canyon" is especially prominent on the left side of the December 1997 and March 1998 spectra. This is due to the blocking of light, called an absorption feature, that probably results from an extended atmospheric "wind" of gas being blown from the surface of Eta Carinae. Note that in the spectra on the right, this canyon grows smaller and almost disappears in the February 1999 spectrum. This indicates that the wind varies with time and has recently changed substantially.

A narrow canyon can also be seen on the left side of the peaks closer to the top. This newly discovered feature indicates high density gas between the star and the observer. Its depth also changes with time. One explanation is that a rotating disk of gas surrounding Eta Carinae alternately brings high and low density regions into view, with the dense regions blocking more light when they rotate between us and Eta Carinae.

Image Credit: NASA/STScI/ Ted Gull / Phil Plait

GSFC Press Release
Images and Captions

GSFC Press Release
Images and Captions

GSFC Press Release
Images and Captions

HUBBLE COMPLETES EIGHT-YEAR EFFORT TO MEASURE EXPANDING UNIVERSE

The Hubble Space Telescope Key Project Team today announced that it has completed efforts to measure precise distances to far-flung galaxies, an essential ingredient needed to determine the age, size and fate of the universe.

"Before Hubble, astronomers could not decide if the universe was 10 billion or 20 billion years old," said team leader Wendy Freedman of the Observatories of the Carnegie Institution of Washington. "The size scale of the universe had a range so vast that it didn't allow astronomers to confront with any certainty many of the most basic questions about the origin and eventual fate of the cosmos. After all these years, we are finally entering an era of precision cosmology. Now we can more reliably address the broader picture of the universe's origin, evolution and destiny."

See the HQ Press Release for further details.

NEW FINDINGS NARROW THEORIES ON COSMIC RAY ORIGIN

Where do those fast-flying atoms that pelt the Earth come from? Scientists catching cosmic rays with a NASA spacecraft have tightened the constraints on the evolving theory of how atoms travelling at nearly the speed of light are produced in stars and are strewn across the Universe through star explosions, or supernovae.

Cosmic rays bombard the Earth's atmosphere constantly. These highly energetic particles are not "rays," however, but rather atoms that were stripped of their electrons when they were accelerated to enormous speeds. While many scientists agree that the energy of supernovae is needed to produce cosmic rays, debates rage over the "seed particles," or the actual atoms that are being accelerated. Are the particles accelerated directly from a supernova, like shrapnel in an explosion? Or are they from dust and gas already present in the region between stars, bumped to high speeds by the blast wave of a supernova explosion?

Results from NASA's Advanced Composition Explorer (ACE) suggest that cosmic rays are not accelerated directly from supernovae, as some current models predict. Rather, it is material that has been sitting around for hundreds of thousands of years that gets accelerated by the shock wave of a supernova explosion.

Dr. Paul Hink of Washington University in St. Louis (WUSL) and a team of scientists from WUSL, California Institute of Technology, NASA's Jet Propulsion Laboratory and NASA's Goddard Space Flight Center present these results from the ACE Cosmic Ray Isotope Spectrometer (CRIS) at the Centennial Meeting of the American Astronomical Society in Chicago on May 31, 1999.   See the GSFC Press Release for further details.

31 May 1999

Astronomers Detect Activity From "Quiet" Supermassive Black Holes

Astronomers have heard the first shy words from seemingly quiet supermassive black holes in the form of a unique type of X-ray light. These black holes exist in the centers of the oldest, largest galaxies and have a mass of about a billion suns, compressed into a region comparable to the size of our solar system.

For more detail, check these links:
GSFC Press Release 99-036

13 April 1999

Astronomers Discover "Middleweight" Black Holes

The field of black holes, formerly dominated by heavyweights packing the gravitational punch of a billion Suns and lightweights just a few times heavier than our Sun, now has a new contender -- a just-discovered mysterious class of "middleweight" black holes, weighing in at 100 to 10,000 Suns.

For more detail, check these links:
HQ Press Release 99-051

13 April 1999

Find First Observational Evidence For "Hypernova" Explosion

Astronomers at Northwestern University and University of Illinois have detected the first observational evidence for the remnants of a hypernova, an explosion a hundred times more energetic than an exploding star (supernova) and the possible source of powerful gamma ray bursts, the most energetic events known in the Universe other than its creation as a result of the Big Bang.

For more detail, check these links:
GSFC Press Release 99-035

12 April 1999

Astronomers Solve The Case Of The Unknown Star Explosion, Discover Rare Coupling Of Elements

Astronomers have pieced together the scene of a crime that no one saw: a 700-year-old star explosion nearly as bright as a full moon, undocumented by early stargazers and unknown to modern-day astronomers until only very recently. Clues came in the form of two radioactive elements never before seen together in such explosions, a rare event that offers a new avenue to test star explosion theories.

For more detail, check this link:
GSFC Press Release 99-037

08 April 1999

FUSE Satellite Arrives In Florida For Launch Preparations

NASA's Far Ultraviolet Spectroscopic Explorer (FUSE) satellite arrived Thursday, April 1 at NASA Hangar AE on Cape Canaveral Air Station to begin prelaunch processing for launch next month.

For more detail, check these links:
KSC Press Release 23-99
FUSE Homepage

02 April 1999

Solar Structures Can Help Forecast
Largest Solar Blasts

"S" marks the spot for scientists trying to forecast solar eruptions that can damage satellites, disrupt communications networks and cause power outages.

Using the Japanese Yohkoh spacecraft, NASA-sponsored scientists have discovered that an S-shaped structure often appears on the Sun in advance of a violent eruption, called a coronal mass ejection, that is as powerful as billions of nuclear explosions.

"Early warnings of approaching solar storms could prove useful to power companies, the communications industry and organizations that operate spacecraft, including NASA," said Dr. George Withbroe, science director for Sun-Earth Connection research at NASA Headquarters. "This is a major step forward in understanding these tremendous storms." (Details) 

NOTE TO EDITORS: Images and supporting material can be found on the Internet at: http://solar.physics.montana.edu/press/  http://www.isas.ac.jp/info/sat/yohkoh-e.html#Tag:0   http://solar.physics.montana.edu/YPOP/

15 March 1999

Hubble Finds More Evidence of Galactic Cannibalism

This beautiful, eerie silhouette of dark dust clouds against the glowing nucleus of the elliptical galaxy NGC 1316 may represent the aftermath of a 100 million year old cosmic collision between the elliptical and a smaller companion galaxy.

A number of faint objects are scattered across the image, including both reddish galaxies in the distant background and bluer, point-like star clusters orbiting NGC 1316. These clusters, relatively loosely-knit swarms containing a few thousand stars each, are smaller and fainter than those found in other elliptical galaxies. These clusters are too old to have been created in the collision which produced the dusty debris we see today, and too young to have been torn apart by galactic tidal forces. The clusters may have been born in the course of a still earlier collision, or belonged to the galaxy which most recently fell victim to NGC 1316.

The picture was taken in April of 1996 with the Wide Field Planetary Camera 2. The color rendition was constructed using separate images taken in blue and red light. NGC 1316 is located 53 million light-years away in the constellation Fornax. The field of view shown is about 12,000 light-years across.

Credit: Carl Grillmair (California Institute of Technology) and NASA
The Space Telescope Science Institute is operated by the Association of Universities for Research in Astronomy, Inc. (AURA), for NASA, under contract with the Goddard Space Flight Center, Greenbelt, MD. The Hubble Space Telescope is a project of international cooperation between NASA and the European Space Agency (ESA).

( Full Story) (2/18/99)

18 February 1999

SOHO Spacecraft Detects Source Of High Speed "Wind" From The Sun

Like water gushing through cracks in a dam, scientists observed "fountains" of electrified gas, called the solar wind, flowing around magnetic regions on the Sun to begin a two million mile per hour rush into space. Using the Solar and Heliospheric Observatory (SOHO) spacecraft, American and European scientists observed solar wind flows coming from the edges of honey-comb shaped patterns of magnetic fields at the surface of the Sun. These observations are presented in the Feb. 5 issue of SCIENCE magazine. The research will lead to better understanding of the high speed solar wind, a stream of electrified gas that affects the Earth's space environment.

For more detail, check this link:
Press Release 99-020

04 February 1999

Gamma Ray Burst Imaged For First Time

Astronomers racing the clock managed to take the first-ever optical images of one of the most powerful explosions in the Universe -- a gamma ray burst -- as it was occurring on Saturday, Jan. 23, 1999. Gamma ray bursts produce more energy in a very short period than the rest of the entire Universe combined. (Details)

01 February 1999

Third EGRET Catalog

Press Release 99-002

An online version of the Third EGRET Catalog is available by clicking the link and will be published in an upcoming issue of Astrophysical Journal Supplements.

Researchers working with the Energetic Gamma Ray Experiment Telescope (EGRET) on NASA's Compton Gamma Ray Observatory spacecraft have cataloged the entire high-energy gamma-ray sky as we know it, from pulsars in our own Galaxy to blazars at the farthest ends of the Universe.

This Third EGRET Catalog, presented at the 193rd American Astronomical Society Meeting in Austin, Texas, contains 271 gamma-ray sources detected from 1991-1995, including the Large Magellanic Cloud, the great solar flare of 1991, a probable radio galaxy, and 170 sources yet unidentified.

"This catalog includes all the high-energy gamma ray sources in the Universe that could be detected by EGRET," said Dr. Robert Hartman, an astrophysicist on the EGRET team at NASA's Goddard Space Flight Center. "This is a huge step for gamma-ray astronomy from the early days 25 years ago, yet in many ways the field is still in its infancy."

19 January 1999

Press Release 99-003
Photo Release 99-005P

X-Ray Pulsar With Companion Star Images

This is an artist's conception of an X-ray pulsar in a binary star system: Matter from a companion star, most likely a Red Giant, channels onto a rapidly spinning neutron star at its magnetic poles. Magnetic fields run in loops from pole to pole. Radiation in the form of X-rays appears to pulse on and off as hot patches of gas are exposed at the poles with the neutron star's rotation. (The axis of rotation is different from the axis of the magnetic field.) The neutron star -- more massive than the Sun yet with a diameter of only 10-15 kilometers -- is extremely dense. Its strong gravitational force accelerates infalling matter to high energies.

Art Credit: Maggie Masetti, NASA

THE ONLY KNOWN BURSTING PULSAR PROVIDES CLUES TO PULSAR NATURE

Astronomers observing the unique "Bursting Pulsar" -- the only pulsar known to generate both regular pulses and frequent enormous bursts of radiation -- have characterized the relationship between the two phenomena. This may shed light on the pulsing mechanism behind other pulsars and how it is affected by magnetic fields, companion stars and occasional bursts of radiation.

Dr. Michael Stark, an astrophysicist with NASA's Goddard Space Flight Center (GSFC) and the University of Maryland, College Park, and Dr. Keith Jahoda, astrophysicist in the X-ray branch at GSFC, present their findings at the 193rd American Astronomical Society Meeting in Austin, Texas.

11 January 1999