Lynn Jenner
Goddard Space Flight Center, Greenbelt, MD
(Phone:  301 286-0045)

RELEASE:  99-37

WIRE SCIENCE INSTRUMENT RUNS OUT OF HYDROGEN

        Ground controllers are slowly gaining control of NASA's Wide-Field Infrared Explorer (WIRE), but the entire supply of
frozen hydrogen needed to cool its primary scientific instrument has been released into space, ending the scientific mission of
the spacecraft.

       "We are very disappointed at the loss of WIRE's science program," said Dr. Ed Weiler, NASA's Associate Administrator for space Science at NASA Headquarters, Washington, DC.  "We are establishing a formal anomaly investigation board to find out what happened, which will help us to plan future missions.  I'm confident that many of the scientific goals can be accomplished by upcoming missions such as the Space Infrared Telescope Facility, so it will be science delayed rather than science lost."

       Spacecraft controllers believe the primary telescope cover was released about three days earlier than planned. As a
result sunlight began to fall on the instrument's cryostat, a container of frozen hydrogen designed to cool the instrument.
The hydrogen then warmed up and vented into space at a much higher rate than it was designed to do, causing the spacecraft
to spin.  Controllers do not know what specifically caused the cover to be released.

     WIRE's primary instrument is a 30-centimeter aperture (12.5-inch) Cassegrain telescope enclosed inside a solid
hydrogen cryostat.  The cryostat was designed to cool the telescope's inner workings to minus-430 degrees F -- cold enough so that the telescope's own heat emissions would not mask the infrared light that it is trying to detect in space.

      By early Saturday, the spacecraft's rate of spin had stabilized at about 60 revolutions per minute, giving
controllers hope they could start the painstaking process of regaining control of the 563-pound spacecraft.  On Saturday,
ground controllers developed and uploaded a new computer program to WIRE that began imparting small, countering forces using the satellite's onboard magnetic attitude control system to gently slow the spacecraft's spin.

     Controllers have been successfully using this approach to slowly regain control of the spacecraft and reduce the spin rate
approximately 3 degrees per second per orbit.  WIRE is now rotating about 250 degrees per second.  The objective is to
reduce the spin rate sufficiently that the onboard system will take over and provide full attitude control. Controllers are
hopeful this will be accomplished by the end of this week.

     "The spacecraft was never designed to be controlled in this manner," said Jim Watzin, Small Explorer Project Manager, "so
it's slow, tedious work.  I'm confident by week's end we will have WIRE in a stable configuration, available for any analysis
deemed appropriate."

     WIRE was launched March 4 at 9:57 p.m. EST from Vandenberg Air Force Base, CA. When the spacecraft made its second pass over one of the WIRE tracking stations, ground controllers determined that WIRE was spinning instead of maintaining a stable position in orbit, and temperatures for the cryostat and the instrument were warmer than expected.

    After the anomaly investigation board completes its work with WIRE, engineers plan to use the spacecraft as an
engineering testbed to evaluate advanced attitude control systems, communications, and data handling and operations.

- end -

                 James Hartsfield
                 Johnson Space Center
                 (713) 483-5111

                 David Salsbury
                 Stanford University
                 (415) 723-2558

                 Release: 96-160

                 METEORITE YIELDS EVIDENCE OF PRIMITIVE LIFE ON
                 EARLY MARS
 

                 A NASA research team of scientists at the Johnson Space Center and at Stanford
                 University has found evidence that strongly suggests primitive life may have existed
                 on Mars more than 3.6 billion years ago.

                 The NASA-funded team found the first organic molecules thought to be of Martian
                 origin; several mineral features characteristic of biological activity; and possible
                 microscopic fossils of primitive, bacteria-like organisms inside of an ancient
                 Martian rock that fell to Earth as a meteorite. This array of indirect evidence of
                 past life will be reported in the Aug. 16 issue of the journal Science, presenting the
                 investigation to the scientific community at large to reach a future consensus that
                 will either confirm or deny the team's conclusion.

                 The two-year investigation was co-led by planetary scientists Dr. David McKay,
                 Dr. Everett Gibson and Kathie Thomas-Keprta of Lockheed-Martin, all from
                 JSC, with the major collaboration of a Stanford team headed by Professor of
                 Chemistry Dr. Richard Zare, as well as six other NASA and university research
                 partners.

                 "There is not any one finding that leads us to believe that this is evidence of past life
                 on Mars. Rather, it is a combination of many things that we have found," McKay
                 said. "They include Stanford's detection of an apparently unique pattern of organic
                 molecules, carbon compounds that are the basis of life. We also found several
                 unusual mineral phases that are known products of primitive microscopic
                 organisms on Earth. Structures that could be microsopic fossils seem to support all
                 of this. The relationship of all of these things in terms of location – within a few
                 hundred thousandths of an inch of one another – is the most compelling evidence."

                 "It is very difficult to prove life existed 3.6 billion years ago on Earth, let alone on
                 Mars," Zare said. "The existing standard of proof, which we think we have met,
                 includes having an accurately dated sample that contains native microfossils,
                 mineralogical features characteristic of life, and evidence of complex organic
                 chemistry."

                 "For two years, we have applied state-of-the-art technology to perform these
                 analyses, and we believe we have found quite reasonable evidence of past life on
                 Mars," Gibson added. "We don't claim that we have conclusively proven it. We
                 are putting this evidence out to the scientific community for other investigators to
                 verify, enhance, attack -- disprove if they can -- as part of the scientific process.
                 Then, within a year or two, we hope to resolve the question one way or the other."

                 "What we have found to be the most reasonable interpretation is of such radical
                 nature that it will only be accepted or rejected after other groups either confirm our
                 findings or overturn them," McKay added.

                 The igneous rock in the 4.2-pound, potato-sized meteorite has been age-dated to
                 about 4.5 billion years, the period when the planet Mars formed. The rock is
                 believed to have originated underneath the Martian surface and to have been
                 extensively fractured by impacts as meteorites bombarded the planets in the early
                 inner solar system. Between 3.6 billion and 4 billion years ago, a time when it is
                 generally thought that the planet was warmer and wetter, water is believed to have
                 penetrated fractures in the subsurface rock, possibly forming an underground water
                 system.

                 Because the water was saturated with carbon dioxide from the Martian
                 atmosphere, carbonate minerals were deposited in the fractures. The team's
                 findings indicate living organisms may also have assisted in the formation of the
                 carbonate, and some remains of the microscopic organisms may have become
                 fossilized, in a fashion similar to the formation of fossils in limestone on Earth. Then,
                 15 million years ago, a huge comet or asteroid struck Mars, ejecting a piece of the
                 rock from its subsurface location with enough force to escape the planet. For
                 millions of years, the chunk of rock floated through space. It encountered Earth's
                 atmosphere 13,000 years ago and fell in Antarctica as a meteorite.

                 It is in the tiny globs of carbonate that the researchers found a number of features
                 that can be interpreted as suggesting past life. Stanford found easily detectable
                 amounts of organic molecules called polycyclic aromatic hydrocarbons (PAHs)
                 concentrated in the vicinity of the carbonate. Researchers at JSC found mineral
                 compounds commonly associated with microscopic organisms and the possible
                 microscopic fossil structures.

                 The largest of the possible fossils are less than 1/100th the diameter of a human
                 hair, and most are about 1/1000th the diameter of a human hair – small enough that
                 it would take about a thousand laid end-to-end to span the dot at the end of this
                 sentence. Some are egg-shaped while others are tubular. In appearance and size,
                 the structures are strikingly similiar to microscopic fossils of the tiniest bacteria
                 found on Earth.

                 The meteorite, called ALH84001, was found in 1984 in Allan Hills ice field,
                 Antarctica, by an annual expedition of the National Science Foundation's Antarctic
                 Meterorite Program. It was preserved for study in JSC's Meteorite Processing
                 Laboratory and its possible Martian origin was not recognized until 1993. It is one
                 of only 12 meteorites identified so far that match the unique Martian chemistry
                 measured by the Viking spacecraft that landed on Mars in 1976. ALH84001 is by
                 far the oldest of the 12 Martian meteorites, more than three times as old as any
                 other.

                 Many of the team's findings were made possible only because of very recent
                 technological advances in high-resolution scanning electron microscopy and laser
                 mass spectrometry. Only a few years ago, many of the features that they report
                 were undetectable. Although past studies of this meteorite and others of Martian
                 origin failed to detect evidence of past life, they were generally performed using
                 lower levels of magnification, without the benefit of the technology used in this
                 research. The recent discovery of extremely small bacteria on Earth, called
                 nanobacteria, prompted the team to perform this work at a much finer scale than
                 past efforts.

                 The nine authors of the Science report include McKay, Gibson and
                 Thomas-Keprta of JSC; Christopher Romanek, formerly a National Research
                 Council post-doctoral fellow at JSC who is now a staff scientist at the Savannah
                 River Ecology Laboratory at the University of Georgia; Hojatollah Vali, a National
                 Research Council post-doctoral fellow at JSC and a staff scientist at McGill
                 University, Montreal, Quebec, Canada; and Zare, graduate students Simon J.
                 Clemett and Claude R. Maechling and post-doctoral student Xavier Chillier of the
                 Stanford University Department of Chemistry.

                 The team of researchers includes a wide variety of expertise, including
                 microbiology, mineralogy, analytical techniques, geochemistry and organic
                 chemistry, and the analysis crossed all of these disciplines. Further details on the
                 findings presented in the Science article include:

                 Researchers at Stanford University used a laser mass spectrometer -- the most
                 sensitive instrument of its type in the world – to look for the presence of the
                 common family of organic molecules called PAHs. When microorganisms die, the
                 complex organic molecules that they contain frequently degrade into PAHs. PAHs
                 are often associated with ancient sedimentary rocks, coals and petroleum on Earth
                 and can be common air pollutants. Not only did the scientists find PAHs in easily
                 detectable amounts in ALH84001, but they found that these molecules were
                 concentrated in the vicinity of the carbonate globules. This finding appears
                 consistent with the proposition that they are a result of the fossilization process. In
                 addtion, the unique composition of the meteorite's PAHs is consistent with what
                 the scientists expect from the fossilization of very primitive microorganisms. On
                 Earth, PAHs virtually always occur in thousands of forms, but, in the meteorite,
                 they are dominated by only about a half-dozen different compounds. The simplicity
                 of this mixture, combined with the lack of light-weight PAHs like napthalene, also
                 differs substantially from that of PAHs previously measured in non-Martian
                 meteorites.

                 The team found unusual compounds -- iron sulfides and magnetite -- that are
                 commonly produced by anaerobic bacteria and other microscopic organisms on
                 Earth. The compounds were found in locations directly associated with the
                 fossil-like structures and carbonate globules in the meteorite. Extreme conditions --
                 conditions very unlikely to have been encountered by the meteorite -- would have
                 been required to produce these compounds in close proximity to one another if life
                 were not involved. The carbonate also contained tiny grains of magnetite that are
                 almost identical to magnetic fossil remnants often left by certain bacteria found on
                 Earth. Other minerals commonly associated with biological activity on Earth were
                 found in the carbonate as well.

                 The formation of the carbonate or fossils by living organisms while the meteorite
                 was in the Antarctic was deemed unlikely for several reasons. The carbonate was
                 age dated using a parent-daughter isotope method and found to be 3.6 billion
                 years old, and the organic molecules were first detected well within the ancient
                 carbonate. In addition, the team analyzed representative samples of other
                 meteorites from Antarctica and found no evidence of fossil-like structures, organic
                 molecules or possible biologically produced compounds and minerals similiar to
                 those in the ALH84001 meteorite. The composition and location of PAHs organic
                 molecules found in the meteorite also appeared to confirm that the possible
                 evidence of life was extraterrestrial. No PAHs were found in the meteorite's
                 exterior crust, but the concentration of PAHs increased in the meteorite's interior to
                 levels higher than ever found in Antarctica. Higher concentrations of PAHs would
                 have likely been found on the exterior of the meteorite, decreasing toward the
                 interior, if the organic molecules are the result of contamination of the meteorite on
                 Earth.

                 --end--

     Contact: James Hathaway
     Hathaway@asu.edu
     602-965-6375
     Arizona State University College of Liberal Arts & Sciences

     Comets, Like Cars, Leave Carbon Monoxide In Their Wake

     Hitching a ride on a comet may be like latching onto a bus's tailpipe, a recent Arizona State University study found.
     The study, done by ASU astronomers and published in the February 10 issue of The Astrophysical Journal, found
     that comet gas tails, previously thought to be composed mostly of water, actually contain high concentrations of
     ionized carbon monoxide (CO) gas similar to the non-ionized form that hovers over the freeways of New York,
     Los Angeles and Phoenix.

     The heart of a comet is its nucleus, a dirty snowball a few kilometers in size that sheds gas and dust when heated
     by the Sun. Comets generally have two tails, a dust and a gas tail. Because the icy nucleus is made primarily of
     water ice, not dry ice (frozen carbon dioxide) or other ices, scientists previously assumed that the tails of comets
     would likewise be comprised mostly of water. Surprisingly, according to the ASU study, they're not.

     According to Susan Wyckoff, ASU astronomy professor and lead author of the paper, "these results are exciting
     because for nearly fifty years we've been using the dirty snowball model for comets and gotten a lot of evidence
     that water is the predominant molecule in the nuclei. When we measured ionized water and carbon monoxide
     levels in the tails, 10 to 20 million kilometers from the nuclei, we found that the ratio actually reverses."

     The ASU team, including Wyckoff, computer specialist Rodney Heyd and undergraduate student Rebecca Fox,
     explain that the lack of water ions in comet tails is due largely to the relatively fragile nature of water molecules
     compared with carbon monoxide molecules when exposed to sunlight.

     According to Wyckoff, survivability is the key factor that can explain the observations. "Because the gas tails of
     comets extend tens of millions of kilometers from the nuclei," said Wyckoff, "the molecules need to be able to
     survive the trip that takes several days while exposed to ultraviolet sunlight."

     Ultraviolet sunlight is very energetic and can break chemical bonds. Because the bond strength of carbon
     monoxide is much greater than that of water, carbon monoxide can survive this trip much better than water can.
     While a water molecule will break apart into hydrogen and oxygen atoms after only about one day of exposure to
     the sun, carbon monoxide is much heartier in the Sun's ultraviolet light, and can survive for about ten days. For this
     reason, it is mostly carbon monoxide gas, not water, which finally reaches the tail. The gas that makes this trip is
     ionized (missing one electron) and is propelled tailward by the Sun's magnetized solar wind.

     Observations that led to this discovery included the two recent comets-two of the brightest of this
     century-Hale-Bopp (of California cult fame) and Hyakutake, and were made using telescopes at the Kitt Peak
     National Observatory and the University of Arizona's Steward Observatory. The team was prompted to look at
     carbon monoxide levels after finding almost no water in the tail of Hale-Bopp.

     In addition to finding high levels of carbon monoxide, the ASU team also discovered an unidentified molecule in
     the comets' gas tails, one first seen first in Halley's Comet 13 years ago. According to Wyckoff, in the 13 years
     since that discovery the molecule has still not been identified. Wyckoff hopes that NASA's recently launched
     Stardust mission, set to rendezvous with comet Wild2 and bring back materials from the tail, will allow scientists to
     finally analyze and identify the unknown molecule.

                                               ###

     To see the ASU team's paper, visit http://www.journals.uchicago.edu/ApJ/journal/ and click on Rapid Release
     ApJ Letters. Photography showing gas and dust tails on Comet Hale-Bopp can be found at
     http://pulsar.la.asu.edu/~chris/comarch2/031597c-f.jpg and at
     http://pulsar.la.asu.edu/~chris/comarch/comarch.html .

Contact numbers:

Jane Greaves (JAC)
jsg@jach.hawaii.edu
phone (USA) (808) 969 6562 (until July 3rd)
phone (USA) (805) 683 6722, room 214 (from July 5th)

USA Press Contact:
Stuart Wolpert (UCLA)
stuartw@college.ucla.edu
phone (USA) (310) 206 0511

UK Press Contact:
Helen Walker (RAL)
hjw@ast.star.rl.ac.uk
phone (UK) 01235 446490

Wednesday 8th July, 1998

Astronomers discover a nearby star system just like our own Solar System

HILO, HAWAII -- An international team of astronomers from the Joint Astronomy Centre (JAC) in Hawaii, the University of California at Los Angeles (UCLA) and the Royal Observatory in Edinburgh announced today the discovery of a ring of dust particles around a nearby star, Epsilon Eridani, that appears to signify a Solar System very similar to our own.

The ring is "strikingly similar" to the outer comet zone in our Solar System, and shows an intriguing bright region that may be particles trapped around a young planet, said JAC astronomer Jane Greaves, who led the research team.

"What we see looks just like the comet belt on the outskirts of our Solar System, only younger," said Greaves, who presented the findings today at the "Protostars and Planets" Conference in Santa Barbara. "It's the first time we've seen anything like this around a star similar to our Sun. In addition, we were amazed to see a bright spot in the ring, which may be dust trapped in orbit around a planet."

Why is Epsilon Eridani so interesting?

Greaves was a member of the international team that reported new images of dusty disks around the hotter stars Fomalhaut and Vega in April (Dusty Disks). However, the new image of Epsilon Eridani is even more exciting for several reasons:

"Epsilon Eridani is far more similar to our Sun than either Vega Fomalhaut." she said. "This star system is a strong candidate for planets, but if there are planets, it's unlikely there could be life yet. When the Earth was this young, it was still being very heavily bombarded by comets and other debris."

"It is also a star in our local neighbourhood, being only about 10 light years away, which is why we can see so much detail in the new image"

Epsilon Eridani is clearly visible to the naked eye, in the constellation Eridanus (the River), which stretches from the foot of
Orion (near the bright star Rigel) to the 9th brightest star in the sky, the southerly Achernar (barely visible from the USA and Europe). Epsilon Eridani is among the 10 closest star systems to the Earth.

"If an astronomer could have seen what our Solar System looked like four billion years ago, it would have been very much as Epsilon Eridani looks today," said Benjamin Zuckerman, UCLA professor of physics and astronomy. "This is a star system very like our own, and the first time anyone has found something that truly resembles our Solar System; it's one thing to suspect that it exists, but another to actually see it, and this is the first observational evidence."

The research team -- which also includes astronomers from the University of Arizona, University College London, and the
Rutherford Appleton Laboratory -- has submitted its findings to the Astrophysical Journal Letters, the most widely-read
scholarly journal in astronomy.

More about the discovery:

Beyond Pluto in our Solar System is a region containing more than 70,000 large comets, and hundreds of millions of smaller ones, called the "Kuiper belt". The image obtained by Greaves' team shows dust particles that the astronomers believe are analogous to our Kuiper belt at the same distance from Epsilon Eridani as the Kuiper belt is from our Sun. Although the image cannot reveal comets directly, the dust that is revealed is believed to be debris from comets, Greaves said.

Epsilon Eridani's inner region contains about 1,000 times more dust than our Solar System's inner region, which may mean it has about 1,000 times more comets, the astronomers said. Epsilon Eridani is believed to be only 500 million years to 1 billion years old; our Sun is estimated to be 4.5 billion years old, and its inner region is believed to have looked very similar at that age.

In our Solar System, the first 600 million years was a time of "heavy bombardment" when the planets were assaulted by massive meteorites and other celestial objects until the gravitation of Jupiter and Saturn cleaned out these destructive objects. Life on Earth probably did not start until after the era of heavy bombardment, said JAC astronomer Wayne Holland.

How was the new image obtained?

The new image -- which is from short-radio wavelengths, and is not an optical picture -- was obtained using the 15-meter
James Clerk Maxwell Telescope at the Mauna Kea Observatory in Hilo, Hawaii. The JCMT is the world's largest telescope dedicated to the study of light at "submillimeter" wavelengths. The team of astronomers used a revolutionary new camera called SCUBA (Submillimeter Common User Bolometer Array), which was built by the Royal Observatory in Edinburgh (which is now the UK Astronomical Technology Centre). SCUBA uses detectors cooled to a tenth of a degree above absolute zero (-273 degrees Celsius) to measure the tiny amounts of heat emission from small dust particles at a wavelength close to one-millimeter.

Implications and mysteries of the new discovery

What is the significance of the similarity between Epsilon Eridani and our own Solar System?

"The implication is that if there is one system similar to ours at such a close star, presumably there are many others," Zuckerman said. "In the search for life elsewhere in the universe, we have never known where to look before. Now, we are closing in on the right candidates in the search for life."

Epsilon Eridani is probably too young to support even primitive life, the astronomers said, but there may be other similar star systems that are billions of years older, and are good candidates to search for life. Although astronomers have not yet located a star system that is the right age with the right atmosphere to support life, they are getting closer.

A region near the star that is partially evacuated indicates that planets may have formed, the astronomers said; the presence of planets is the most likely explanation for the absence of dust in this region because planets absorb the dust when they form.

What is the bizarre bright spot in the image obtained by the astronomers?

"There may be a planet stirring up the dust in the ring and causing the bright spot," said Bill Dent of the Royal Observatory,
Edinburgh, "or it could be the remnants of a massive collision between comets."

Epsilon Eridani is about three-quarters as massive as the sun, but only one-third as luminous. When astronomer Frank Drake conducted the first serious search for radio signals from other civilizations in the late 1950s, Epsilon Eridani was one of the first two stars he studied. Today, researchers know something Drake did not: Epsilon Eridani is much too young to have intelligent life. However, the new image shows there may be at least one planet, and perhaps life in the future.

In addition to Greaves, Holland, Zuckerman and Dent, the astronomers on the project are Gerald Moriarty-Schieven and Tim Jenness at JAC; Harold Butner at the University of Arizona, Tucson; Walter Gear at University College London; Helen Walker at the Rutherford Appleton Laboratory; and UCLA graduate students Richard Webb and Chris McCarthy.

Information and images are available on the World Wide Web at website http://www.jach.hawaii.edu/News/kbelt.html.
IMAGE CAPTION:
[http://www.jach.hawaii.edu/News/kbelt/kbelt_image.html]

The submillimetre image of Epsilon Eridani, and how the Solar System would look if seen from the same distance

The left image is a false-colour view of a ring of dust particles around Epsilon Eridani, taken with the SCUBA camera at the JCMT.

The right image is a sketch of how the Solar System would look (in optical light) to an astronomer looking from Eps Eri, drawn to the same scale.

The submillimetre image shows the emission from dust particles, each a fraction of a millimetre in size, orbiting around the star Epsilon Eridani. The false-colour scale shows where the brightest regions are (yellow/red), in contrast to the areas with very little dust (blue/black). The dust lies mainly in a ring around the star, with a radius of 60 Astronomical Units (60 times the size of the Earth's orbit). The star itself was not seen, because its small, hot surface radiates very little at submillimetre wavelengths.

On the outskirts of the Solar System, there are vast numbers of comets beyond the orbit of Pluto (40 Astronomical Units).
These make up the "Kuiper Belt". The sketch shows only a fraction of these comets, and they are not to scale. The giant planets -- Jupiter, Saturn, Uranus and Neptune (also not to scale) -- orbit inside this belt.

The location of the "belt" is remarkably similar in each picture. Epsilon Eridani is much younger than the Sun, only about 0.5-1 billion years old while the Sun is 4.5 billion years old. It is likely that that tiny dust particles around Eps Eri will gradually accumulate into comets like those in the Solar System's Kuiper Belt.

There is one prominent bright peak in the ring around Eps Eri, seen to the lower left of the star. This could be dust particles
trapped in an orbit close to a planet, or (less likely) the remnants of a major comet collision. No-one yet knows if Epsilon
Eridani has planets ... but the new image gives a clue that there may be.

In fact, a very similar picture has emerged of dust orbiting near the Earth. Dermott and co-workers made a simulation of dust trapped in orbits near the Earth, and their computer simulation can be seen here.
[http://www.jach.hawaii.edu/News/kbelt/natpic.gif] It was published in 1994, in the scientific journal Nature. There is a striking similarity between their model for the Earth and our actual image of epsilon Eridani!

New Haven, Conn. -- In the Greek myth of Phaethon, the chariot of the Sun inadvertently drives too close to the Earth, creating the Sahara desert with its scorching heat. Whether that myth is based in some small part on observations of a "superflare" emanating from the Sun and scorching the Earth in past millennia is a question that intrigues Yale University
astrophysicists Bradley E. Schaefer and Eric P. Rubenstein.

At a news conference today during the annual meeting of the American Astronomical Society in Austin, Tex., Schaefer and his colleagues reported that nine stars on which superflares have been observed during the past century are disturbingly similar to our Sun in size, age, luminosity and rotation speed. (Other collaborators on the research were Jeremy R. King, Space Telescope Science Institute, Baltimore, Md.; and Constantine P. Deliyannis, Indiana University, Bloomington).

"It's only natural to ask what would happen on Earth if such a superflare were to suddenly occur on our Sun, or to speculate why such flares apparently have not happened here," Schaefer said. He noted that a superflare -- a flare 100 to 10 million times larger than the largest flare ever seen on our Sun -- would severely disrupt radio communication,
burn out all orbiting satellites, black out power grids worldwide, and create spectacular auroras visible from the poles to the equator.

"Large superflares could warm a cold winter day into a hot summer day," he said. "But the primary damage would come from high energy radiation, which would react in the Earth's upper atmosphere to destroy the protective ozone layer for several years, thereby exposing the Earth's surface to harmful ultraviolet radiation with subsequent collapse of the food chain."

Fortunately, such grim possibilities appear to be unlikely, the researchers agreed. Any superflares on our Sun during the last 150 years of scientific monitoring would certainly have been noted, while any superflare within the last two millenia would likely have appeared in the historical record as a sudden heat wave or global aurora, Schaefer said.
Furthermore, a large superflare probably would have melted the icy surfaces of moons around Jupiter and Saturn, forming vast flood plains. The absence of smooth frozen surfaces on these moons means that large superflares have not occurred in the last billion years or so. "Despite the myth of Phaethon, our Sun apparently has only rare superflares, if
any," Schaefer concluded.

Stars like our Sun have superflares an average of about once a century, the researchers calculated, and it is just this type of star around which planets recently were discovered, opening the door to the exciting possibility of organic life flourishing elsewhere. It is unknown whether recurring superflares would encourage evolution by providing an energy
source for prebiotic chemical reactions or would prevent new lifeforms from gaining a foothold.

Next, Yale scientists hope to find more examples of superflares by monitoring a very large number of stars -- a feat that is possible using a Yale camera mounted on a telescope in Venezuela, which nightly scans more than a million solar-type stars in search of mysterious distant objects called quasars as part of the QUEST project. In addition, theoretical work
to understand the energy-release mechanism of stars might help answer the question of which stars are prone to superflares, Schaefer said.

One theory currently being studied by Rubenstein is that the stars on which superflares have been observed have relatively strong magnetic fields that interact with a nearby large planet about the size of Jupiter, causing the build-up and periodic release of vast amounts of energy.

Rubenstein believes that these outbursts are similar to energetic eruptions observed from some stars in binary systems, in which a pair of stars are gravitationally bound together and orbit around each other. A category of binary stars called RS CVn binaries routinely have eruptions
that release as much energy as superflares, he said.

While astronomers still don't know all of the details of what causes RS
CVn binaries to flare, most accept the theory that energy is released from
the intertwined magnetic fields between the two stars. At some point, the
twisted fields suddenly reorganize into a simpler geometry via a process
called magnetic reconnection, Rubenstein said. When this event occurs, the
magnetic field emerging from one star becomes connected temporarily to the
other star, and vice versa. Stored energy is released in the form of light
and X-rays as the magnetic reconnection occurs. "A similar process would
be a physical system composed of, say, rubber bands twisted together,"
Rubenstein said. "When the elastic bands are released, they suddenly snap
and fly off. The energy is released and channeled into propelling the
rubber bands instead of producing light."

All nine of the superflares identified by Schaefer are either from single
stars or stars with companions too distant to interact magnetically with
the flaring star. However, a nearby planet could cause the same reaction,
even though the planet would be difficult to detect, Rubenstein noted.

"Until two years ago, no planets outside of our solar system had been
detected. Now, more than a dozen planetary systems have been found, most
of which have planets with masses comparable to Jupiter that orbit close
to the parent star. In some cases, these planets are closer to their star
than Mercury is to our Sun," Rubenstein said.

If the Jupiter-sized planets around other stars also have strong magnetic
fields like Jupiter, the combination of proximity and magnetic field
strength could lead to magnetic interactions similar to those observed in
RS CVn binary systems. That interaction would then lead to energy being
stored and subsequently released in the form of a superflare. "Fortunately
for us, there is no danger of a magnetic reconnection being triggered by
Jupiter, which is too far from the Sun, or triggered by the inner four
planets, which have much smaller magnetic field strengths," Rubenstein
said.

Rubenstein's hypothesis can be tested by searching for "stars that have
strong magnetic fields and large, close-by planets," Schaefer said. "Such
stars would be more prone to superflares. In the meantime, we should not
fear Phaethon's chariot."

###

Note to Editors: Many of the observations for this study were made with
the Wisconsin-Indiana-Yale-National Optical Astronomy Observatories (WIYN)
3.5-meter telescope atop Kitt Peak National Observatory near Tucson,
Arizona. For further information, contact Professor Schaefer at (203)
432-3806, e-mail schaefer@grb2.physics.yale.edu; or Rubenstein at (203)
432-3028, e-mail ericr@astro.yale.edu .

• January 20, 1999 - New Scientist

US CONTACT: Barbara Thurlow, New Scientist Washington office Tel: 202-452-1178 or email newscidc@idt.net

EMBARGOED FOR RELEASE: January 20, 1999, 2 p.m. EST

Cataclysmic Explosions May Have Held Up Alien Visitors

GAMMA-RAY bursts -- incredibly powerful explosions that may be caused by collisions between collapsed stars -- could solve one of the oldest riddles about extraterrestrial civilizations: why haven't they reached Earth already? After studying the effects of gamma-ray bursts on life, an astrophysicist has concluded that aliens may have just started to explore their galaxies.

Enthusiasts for the existence of extraterrestrials have long been haunted by a simple question supposedly posed by the Nobel prizewinning physicist Enrico Fermi around 1950. Fermi pointed out that the Galaxy is about 100 000 light years across. So even if a spacefaring race could explore the Galaxy at only a thousandth of the speed of light, it would take them just 100 million years to spread across the entire Galaxy. This is far less than the Galaxy's age of about 10 billion years.

So if ETs exist in the Milky Way, where are they? Maybe they don't share the human urge to explore. Or perhaps there's another reason, says James Annis, an astrophysicist at Fermilab near Chicago. He thinks cataclysmic gamma-ray bursts often sterilise galaxies, wiping out life forms before they have evolved sufficiently to leave their planet (Journal of the British
Interplanetary Society, vol 52, p 19). GRBs are thought to be the most powerful explosions in the Universe, releasing as much energy as a supernova in seconds. Many scientists think the bursts occur when the remnants of dead stars such as neutron stars or black holes collide.

Annis points out that each GRB unleashes devastating amounts of radiation. "If one went off in the Galactic centre, we here two-thirds of the way out on the Galactic disc would be exposed over a few seconds to a wave of powerful gamma rays." He believes this would be lethal to life on land.

The rate of GRBs is about one burst per galaxy every few hundred million years. But Annis says theories of GRBs suggest the rate was much higher in the past, with galaxies suffering one strike every few million years -- far shorter than any plausible time scale for the emergence of intelligent life capable of space travel. That, says Annis, may be the answer to Fermi's question. "They just haven't had enough time to get here yet," he says. "The GRB model essentially resets the available time for the rise of intelligent life to zero each time a burst occurs."

Paul Davies, a visiting physicist at Imperial College, London, says the basic idea for resolving the paradox makes sense. "Any Galaxy-wide sterilising event would do," he says. However, he adds that GRBs may be too brief: "If the drama is all over in seconds, you only zap half a planet. The planet's mass shields the shadowed side." Annis counters that GRBs are likely to have many indirect effects, such as wrecking ozone layers that protect planets from deadly levels of ultraviolet radiation.

Annis also highlights an intriguing implication of the theory: the current rate of GRBs allows intelligent life to evolve for a few hundred million years before being zapped, possibly giving it enough time to reach the spacefaring stage. "It may be that intelligent life has recently sprouted up at many places in the Galaxy and that at least a few groups are busily engaged in spreading."

  ###

Author: Robert Matthews
New Scientist magazine issue 23rd Jan 99

PLEASE MENTION NEW SCIENTIST IF YOU USE THIS ARTICLE - THANK YOU

SKY & TELESCOPE'S NEWS BULLETIN
 
 

JANUARY 29, 1999
 
 

GAMMA-RAY BURST CAUGHT IN THE ACT
 
 

On the morning of January 23rd, astronomers bagged a trophy they have been

trying to capture for years: the first visible-light images of a gamma-ray

burst in progress. The burst took place in the northern part of the

constellation Bootes and was dubbed GRB 990123 for the date it was seen. It

displayed two intense surges about 25 and 40 seconds after it began, then

trailed off in a series of weaker pulses for the next 50 seconds. Its peak

intensity was so strong that it ranked in the top 2 percent of all bursts

on record.
 
 

Carl W. Akerlof and Timothy A. McKay (University of Michigan) managed to

capture the object less than a minute after the gamma-ray event began.

Their camera array, named the Robotic Optical Transient Search Experiment

(ROTSE), swings into action moments after an electronic network signals a

strong burst from the Compton Gamma-Ray Observatory satellite. ROTSE,

assembled from 35-millimeter camera lenses and parts culled from the

amateur astronomy market, began a 5-second exposure just 22 seconds after

GRB 990123 was detected. This first image showed an object shining at 12th

magnitude. By the next exposure, 25 seconds later, it had brightened to

magnitude 9. It faded to fainter than 14th magnitude during the next 10

minutes.
 
 

The catch turned out to be so bright and powerful that it may be hard to

explain by any theory yet devised. For a full report, see the News Page of

Sky & Telescope's Web site (http://www.skypub.com/news/news.html).
 

January 31, 1999 - from astro@lists.mindspring.com Of 'dark matter', inflation, and 'strings,' I believe that inflation is the ONLY theory postulated to explain 'problems' with the Big Bang -- namely the flatness and horizon problems. My impression is that string theory was generated by a desire to find an underlying unity in particle physics. (Is that correct?) Dark matter, despite being used to try to validate the critical density prediction of inflation, was initially postulated to explain anomalous motions within galaxies and galactic clusters -- in particular, why rotational speeds did not drop off with distance from the center in line with Newtonian predictions. So, it may be more appropriate to ascribe what Abel calls 'arrogance' to Newtonian rather than Big Bang theorists. :-)

Nevertheless, by coincidence, I have been thinking in the last couple of days about the analogy between the 'dark matter' postulate and the 'luminiferous ether' postulate. In particular, the latter did not offer any impediment to the motion of material bodies, and the former does not offer any impediment to the propagation of electromagnetic radiation. This seems a little hard for me to swallow. Perhaps there are some exercises that will widen my gullet?

Dark matter is essentially an attempt to use perturbation theory to explain the anomalous motions of stars in galaxies, and galaxies in clusters. It may be well to remember that perturbation theory was used in an earlier attempt to explain an anomaly in Merury's orbital motion.

Finally, however, that was explained by quite a different mechanism from perturbation by an inner planet that was even bestowed a name -- Vulcan. Could 'dark matter' prove to be as imaginary as Vulcan was?

While, as Abel says, there appear to be some problems for Big Bang Theory, it must be remembered that it explains many more things, including a large number of observations that confirmed its predictions -- particularly the Cosmic Background Radiation, or CBR for the acronymically addicted. As for the timescale required for large structures to form, that Abel referred to, I would point out that, among other things, there is more uncertainty in our estimates of the Age of the Universe than we would like. I know of nothing directly contradictory to Big Bang Theory. Though I've been told that Quantum Theory and Relativity are contradictory, or at least incompatible, I've never grasped how or why.

But we still need some theory to explain the anomalies is intra-galactic and intra-cluster motions. :-( It would be neat if such a theory accounted for some other 'funnies' as well -- like Gamma Ray bursts! ;-)

By the way, for those who missed it, The Sky & Telecope News Bulletin (1/29/99) said of GRB 990123, "The catch turned out to be so bright and powerful that it may be hard to explain by any theory yet devised." Hmmm.

Jega A. Arulpragasam <jega@thecia.net> Lunenburg, MA 42 deg 36'N; 71 deg 43'W

RUSSIAN SPACE MIRROR TO BE TESTED THURSDAY EVENING

An unusual and potentially very bright light will shine in the evening sky
over parts of North America and Europe this Thursday. That's when Russian
space officials say their Znamya 2.5 space mirror will be deployed and
tested by orbiting cosmonauts aboard the Mir space station. Future versions
of the satellite could someday shorten the long winter nights of
far-northern cities -- much to the chagrin of backyard skygazers.

The Znamya experiment calls for bouncing sunlight off a circular, 25-meter
(80-foot) reflector and directing the light toward several cities in Europe
and North America after sunset on February 4th. The light beam will be an
estimated 5-7 kilometers (3-4 miles) wide. If the experiment succeeds,
areas along the ground track could be bathed in light five to 10 times
brighter than the full Moon for a few seconds to a few minutes. Cosmonauts
Gennady Padalka and Sergei Avdeyev will orient the reflector by remote
control, attempting to keep it trained on ground targets for one or two
minutes at a time. Observers outside Znamya 2.5's directed beam could see
the spacecraft outshining virtually every star as it coasts across the sky
in an orbit 360 km (225 miles) high.

Amateur astronomers in the targeted cities or living along the ground track
will be well positioned to estimate the brightness of Znamya's reflected
beam of sunlight. According to SKY & TELESCOPE magazine, observers near the
ground track will see Znamya and Mir appear as a bright, slowly moving
"double star." Only if the beam passes directly over your location will
Znamya flare to full-Moon brilliance, and then only if the sky is clear.
Observers under cloudy skies may see the clouds brighten as if illuminated
from within by lightning.

"Most people don't realize you can see orbiting satellites from the
ground," says J. Kelly Beatty, SKY & TELESCOPE's senior editor. "Most are
quite faint and go unnoticed," he adds, "but this one could get so bright
it will be impossible to miss. Those who aren't expecting it may think
they've spotted a UFO."

Details about Znamya (Russian for "banner") are reported in SKY &
TELESCOPE's February issue and on its Web site (www.skypub.com). This Web
site also offers Mir visibility predictions for 100 cities in North America
and 100 other cities worldwide.

Here is the February 4th timetable released last weekend by officials of
the Space Regatta Consortium (SRC), which is funding the Znamya test. Note
that times are approximate and may change a little, depending on Mir's
exact orbit at the time of deployment. (* = February 5th)

     UT     Local time
    (GMT)   on Feb 4th    Event

    10:04                 Progress M-40 undocks from Mir
    11:34                 Znamya 2.5 reflector deploys from Progress
    13:12    6:12 pm      light beam on Karaganda, Kazakhstan
    14:45    5:45 pm      light beam on Saratov, Russia
    16:20    7:20 pm      light beam on Poltava, Ukraine
    17:54    6:54 pm      light beam on Liege, Belgium
    17:56    6:56 pm      light beam on Frankfurt, Germany
    23:54    5:54 pm      light beam on Winnipeg, Manitoba
    23:56    6:56 pm      light beam on Quebec City, Quebec
     1:30*   6:30 pm      light beam on Calgary, Alberta
     1:32*   7:32 pm      light beam on Devil's Lake, North Dakota
     2:13*                Test ends, reflector is released

SRC is a partnership involving seven Russian aerospace management and
engineering organizations. They eventually hope to loft whole
constellations of space mirrors orbiting 1,500 to 4,500 km (930 to 2,800
miles) high. With a diameter of 200 meters (650 feet), each satellite could
beam down a disk of light as wide as a city and up to 100 times the full
Moon's brightness. These cosmic klieg lights could be used to illuminate
high-latitude regions of Earth in the hours after sunset or before sunrise,
ostensibly to improve the spirits and productivity of those forced to
endure long, dark winters. But the prospect of an armada of giant space
mirrors has astronomers worried that our view of the starry sky will be
spoiled by light pollution from the satellites. "The best way to assess the
seriousness of this threat," says SKY & TELESCOPE's Beatty, "is for lots of
experienced skygazers both within and outside the ground track to watch for
Znamya on Thursday evening and estimate how bright it actually gets."
Observing reports may be e-mailed to SKY & TELESCOPE at znamya@skypub.com.

On February 4, 1993, SRC conducted an orbital test of a slightly smaller
reflector called Znamya 2. The spinning space mirror directed a 4-km-wide
(2.5-mile) spot of reflected sunlight along a swath of Europe that lay in
predawn darkness. Although much of the target area was blanketed by clouds,
a few observers reported seeing a 1-second-long flash nearly as bright as
the full Moon.

                                         ###

Additional information is available on SKY & TELESCOPE's Web site at
http://www.skypub.com/news/special/znamya.html

MEDIA RELATIONS OFFICE
JET PROPULSION LABORATORY
CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
PASADENA, CALIFORNIA 91109.  TELEPHONE (818) 354-5011
http://www.jpl.nasa.gov

Contact:  Mary Hardin
         (818) 354-0344

FOR IMMEDIATE RELEASE                         February 4, 1999

MARS GLOBAL SURVEYOR SUCCESSFULLY COMPLETES AEROBRAKING

     NASA's Mars Global Surveyor spacecraft will soon begin its
primary mapping mission after it successfully fired its main
rocket engine early this morning and raised its orbit completely
out of the Martian atmosphere to end the aerobraking phase of the
mission.

     The burn was executed at 12:11 a.m. Pacific time when the
flight team determined that the farthest point in the
spacecraft's orbit had dropped to 450 kilometers (279 miles)
above the Martian surface. During the next two weeks, the
spacecraft's closest approach to Mars will slowly drift south
until it has moved into a circular Sun-synchronous orbit, in
which the spacecraft will cross the Martian equator at about 2
a.m. local solar time.

     "The use of aerobraking has been a pioneering operation for
a spacecraft at Mars, and we now know that we can use this
technique with confidence for future Mars missions," said Glenn
E. Cunningham, deputy director of the Mars Exploration Program at
NASA's Jet Propulsion Laboratory.   "It has been a long and
arduous task that has turned into a valuable learning experience
for all of us - engineer and scientist alike.  The flight team
has done a superb job and we're really glad the aerobraking phase
of the mission is now successfully behind us. We're looking
forward to beginning the primary mapping mission within the next
few weeks."

     The start of the primary mapping mission has been delayed by
about a year due to a structural problem with the spacecraft's
solar panel that required the flight team to take a more cautious
approach to aerobraking to ensure that the weakened panel was not
overstressed.

     In addition to making a photographic map of the entire
planet during one full Martian year (687 Earth days), Mars Global
Surveyor will study the planet's topography, magnetic field,
mineral composition and atmosphere.

     "Global Surveyor will become our first weather satellite at
Mars. During the extended aerobraking phase, the spacecraft was
able to acquire some "bonus" science data that has yielded some
spectacular new findings about Mars.  We now have a profile of
the planet's northern polar cap and information about the unique
nature of its remnant magnetic fields," Cunningham said.

     During the aerobraking technique, the spacecraft uses
frictional drag as it skims through the planet's thin upper
atmosphere to alter the shape of its orbit around the planet.
First tested in the final days of the Magellan mission to Venus
in 1994, the technique is an innovative way of changing the
spacecraft's orbit while carrying less onboard fuel.

     When Global Surveyor arrived at Mars in September 1997, it
initially entered a looping, elliptical orbit around the planet
that has been gradually circularized through aerobraking.  Its
winged solar panels -- which feature a Kapton flap at the tip of
each wing for added drag -- supply most of the surface area that
slowed the spacecraft by a total of more than 1,200 meters per
second (about 2,700 miles per hour) during the entire aerobraking
phase. Since the start of  aerobraking, Surveyor's orbit around
Mars has shrunk from an initial elliptical orbit of 45 hours to
the now nearly circular orbit taking less than two hours to
complete.

     Flight controllers will again fire the spacecraft's main
engine on February 18 and perform a final "transfer to mapping
orbit" burn, which will lower Global Surveyor's closest approach
over Mars from 405 kilometers (253 miles) to approximately 379
kilometers (237 miles).   After a short period of calibrating the
science instruments, mapping will begin in early March.

     Mars Global Surveyor is the first mission in a long-term
program of Mars exploration known as the Mars Surveyor Program
that is managed by the Jet Propulsion Laboratory for NASA's
Office of Space Science, Washington, DC.  JPL's industrial
partner is Lockheed Martin Astronautics, Denver, CO, which
developed and operates the spacecraft.  JPL is a division of the
California Institute of Technology, Pasadena, CA.

                                #####