The Cosmic Mirror

of News events across the Universe

Archival Issues # 1 til 10 of Oct. 10 til Nov. 2, 1996

Compiled and written by Daniel Fischer, Skyweek - back to the Archive

Update #10 of Nov. 2, 1996 0:45 UTC

Posted from Cambridge, MA, U.S.A.

Another big extinction event linked to an impact?

This time it is even more controversial than the connection between the mass extinction 65 Myr ago and the Mexican impact event once was. A geologist claims that the same shocked microscopic quartz crystals that were crucial in proving that link are also present in sediments from the late Permian period, which ended about 250 Myr ago. No mechanism other than a tremendous impact (or a man-made explosion) seems to be able to cause this kind of damage to quartz. The Perm/Trias transition was marked by one of the greatest extinctions ever, and palaeontologists had come up with many clever non-astronomical explanations. Be prepared for more controversy in coming months... (Science Now Oct. 30, 1996)

Another Martian Meteorite in the Headlines

This time it is EETA79001, another Antarctic meteorite that had been the most famous one until 1/4 year ago. It was the first one in which pockets of Martian air had been detected, which led to the widespread acceptance of the Martian origin of the SNC meteorites (Ad Astra July 1996). And it was again EETA79001 in which British researchers claim to have found the first organic matter from Mars in 1989 (Nature July 20, 1989, p. 220-222). Now the same scientists have given a news conference in London, claiming even stronger evidence for this result which was controversial at the time. EETA79001 is much younger than ALH84001: Significant traces of life from Mars in this rock would be strong evidence for life enduring on that planet til the present time.

In 1989 there was suspicion that the organic matter could have been terrestrial contamination, but now the sample was from a part of the meteorite that had been sealed in a glasslike substance before EETA79001 landed in Antarctica. The evidence apparently is purely isotopic: Carbon atoms extracted from the rock have an isotope ratio matching the C ratio in methane produced by bacteria. The British geochemists applied the same test to the carbon compounds in ALH84001 and found the same isotope ratio again - but to claim that this is proof of present live on Mars (as one of the scientists had said) is pretty bold... ( Science Now Oct. 31 + Boston Globe + Florida Today Nov. 1, 1996)

China plans manned spaceflight for 1999

A secret project named "Project 921" has been described to members of an internatiomnal delegation visiting Chinese space centers: Apparently the are plans to launch one or two astronauts in a Gemini-like capsule on a Long March rocket in 1999 - for purely political reasons, namely to celebrate the 50th birthday of the communist state. The development of the capsule must have been under way for several years as should have been the training of the astronauts - they will have watched the mixed success of Long March launches in recent years with great interest... For 1998, the visitors heard, an unmanned test flight is planned. And there seem to be even vague plans for a Chinese space station, to be launched around 2020. (AW&ST Oct. 21, 1996, p.22)

Briefly noted:

The third Galileo encounter with a Jovian satellite begins today: The highlight of " C3 " will be a flight over Callisto at an altitude of 1118 km). This is going to happen exactly. Meanwhile the launch of the Pegasus rocket with SAC-B and HETE has been halted until at least Monday.

The HST images of the current dust storm on Mars (see Update #7) have already become available: When watching them remember how small the Martian disk is a the moment! Meanwhile a group of young students will take a virtual trip to Mars this month when they remotely steer a Russian-built robotic rover through a barren Arizona desert from their classrooms. Using their computers and the Internet, the students will control the rover as it navigates through a sparsely-vegetated area during a NASA field test to simulate future robotic exploration of the red planet - and everybody can look on here.

111 molecules in space are known to date: The largest one is HC9N with 11 atoms (claims that HC11N has been seen as well turned out to be incorrect). Nearly all of the larger molecules are carbon chains; only three of them are rings, and no ball-shaped fullerenes have been found so far. The laboratory study of long carbon chains (a somewhat dangerous pastime, as some of the compounds are explosive) is now catching up with the astronomical observations. (Talk by M. McCarthy in Cambridge, MA, on Oct. 31st, 1996).

Update #9 of Oct. 31, 1996 01:00 UTC

Posted from Cambridge, MA, U.S.A.

Pegasus launch delayed til Friday

The countdown for the winged rocket carrying SAC-B and HETE (see Update #8) ran to t-5 seconds, but then the countdown was stopped when one of the rudder pins did not retract from the Pegasus rocket. Soon the battery power for the rocket's fins expired, forcing the abort and scrub for Oct. 30th.The launch of Pegasus/HETE and SAC-B, to occur off Wallops Island, Va., is now scheduled for no earlier than Friday. Over the next 48 hours, controllers will continue to troubleshoot yesterday's problem, and replace the fin batteries for the next attempt. (Adapted from Florida Today Online)
Meanwhile, learn more about the history of the Gamma Ray Bursts which SAC-B and especially HETE are to study - and about Violence in the Cosmos in general!

Briefly noted:

Still no firm launch date set for STS-80: Only on Monday will managers decide whether to launch Columbia on Nov. 8th - mysterious damage found in the retrieved boosters from the last mission is causing considerable concern. STS-80 will be a very special mission for one of the passengers: It's mission number six for Story Musgrave, who with 61 years is also the oldest active astronaut. (Florida Today Oct. 30, and Boston Globe Oct. 29, 1996)

Are the "DIBs" simple hydrogen molecules? It's one of the oldest unsolved mysteries in astrophysics: What component of the interstellar medium is causing widely observed diffuse absorption bands in stellar spectra? Most astronomers were betting on complicated molecules with many atoms (PAHs, e.g., or fullerenes) - but now it seems possible that simple molecular hydrogen is to blame, albeit in a specially excited state. (Science Now Oct. 29, 1996)

Spectacular new image of the ocean floor: A dramatic geophysical data product from the NOAO is visualizing the spreading of the sea floor and the formation of new earth crust by color-coding is age. This image can also be bought from the U.S. government. (CNN Online Oct. 30, 1996)

Update #8 of Oct. 29, 1996 18:45 UTC

Posted from Cambridge, MA, U.S.A. (includes DPS'96 wrap-up)

Launch of new High-Energy Astrophysics Spacecraft Approaches

Oct. 30 is the latest date set for the launch of HETE and SAC-B, an American and an Argentinian small satellite with instruments for x-ray and gamma astronomy. The launch window opens around 17:30 UTC on that day. They are supposed to fly on a Pegasus-XL winged rocket, and the launch delay by one day was apparently caused by problems in related small science satellites due to fly on the Pegasus.

SAC-B (Scientific Applications Satellite-B) is an international cooperative project between NASA and the Space Agency of Argentina, CONAE. The spacecraft, which is managed by the GSFC International Projects Office, will observe solar flares, gamma ray bursts, the diffuse cosmic X-ray background and energetic neutral atoms. Argentina has built the satellite (total mass 181 kg) and one instrument, NASA built two others, and Italy provided the solar arrays and yet another instrument.

HETE, the High Energy Transient Experiment, weighs only a little more than 100 kg and was built at the MIT in Cambridge, MA. It carries three instruments: a gamma burst detector, an x-ray camera with a coded mask, and UV cameras. Together these instruments will try to solve one of the greatest mysteries of contemporary astrophysics: Where do the Gamma Ray Bursts (GRBs) originate? Not only will the satellite itself try to observe the bursts and their possible aftereffects itself: It will broadcast the detection of a burst in realtime over a freely available radio link to astronomers around the world. Any amateurs up to the challenge?! (With NASA News Release # 213 Oct. 21, 1996)

Most of Earth's Oxygen Supply Produced by Geologic Events ?

Did global-scale geologic events produce the bulk of the Earth's oxygen supply - and not the plant life in its early oceans, as the traditional view sees it? Research performed at the NASA Ames Research Center by David DesMarais correlates oxygen "surges" in the atmosphere 2.2 to 2.0 billion years ago with changes in the amount of carbon stored in Earth's crust at that time when several of Earth's "micro" continents crashed together forming new, stable modern-sized continents. As the continental fragments collided, towering mountain ranges formed. Their steep slopes produced rapid erosion and sedimentation, key to the new theory presented at a meeting in Denver.

Orgnic matter is normally consumed by bacteria and animals, a process that utilizes oxygen (respiration), producing energy and carbon dioxide and water as by-products. According to DesMarais, when huge amounts of organic matter were buried during cataclysmic collisions, oxygen was freed to accumulate in Earth's early atmosphere. "The cycle of photosynthesis (which produces oxygen) and respiration (where oxygen is consumed) is an almost break-even process," DesMarais said. Only when large amounts of organic material are buried in ocean sediments during tectonic upheavals can the amount of oxygen in the atmosphere increase substantially, he added.

An independent recent study concludes that approximately three large continental masses were assembled between 2.5 and 1.9 billion years ago by the collision of smaller land masses. Two of these were assembled between 2.2 and 1.9 billion years ago. These collisions formed Himalayan-class mountains with high rates of sedimentation in the ocean, burying organic matter. According to DesMarais, the formation of stable, large continents also protects and stores larger amounts of organic carbon for hundreds of millions of years, further allowing the atmosphere to accumulate large amounts of free oxygen. (Adapted from NASA News Release # 219 Oct. 29, 1996)

Strange double-meteor detected seismically

The unique meteoroid that flew through the Earth's atmosphere twice on two subsequent orbits, before it went down somewhere in California (see Update #3), has also been detected by a network of 31 seismographs. During its final entry the meteor exploded in midair at least twice, and soundwaves similar to sonic booms were detected by the seismographs. From those signals the point of impact of any remaining meteoritic particles could be narrowed down further: It is the Rose Valley near Little Lake, a desert region at the base of the southeastern flank of the Sierra Nevada. All those heading out there now should be warned, though: The $ 5000 reward for the first chunk of the meteorite recovered will only be paid out for a piece weighing more han 4 ounces... (New York Times Oct. 27, 1996)

Final Brief Notes from the 28th DPS Meeting in Tucson, AZ:

Water from the Rings is Raining onto Saturn! A remarkable hypothesis about the short lifetime of Saturn's spectacular ring system has apparently been confirmed by UV spectroscopy with the Hubble Space Telescope: At wavelengths below 180 nm there is an enormous water absorption feature in the clouds of the planet which is due to water - which can be traced back to the ring system. The latter is being eroded by micrometeorite hits, and some of the chipped-off particles get negatively charged and follow Saturn's magnetic field lines straight into its cloud deck. This fact will allow to determine the erosion rate (and thus the age) of the rings from the water abundance of Saturn's clouds.

Still Haze left from Shoemaker-Levy 9 on Jupiter! Both with its spectrographs and with its cameras the Hubble Space Telescope can still see hazy reminders of The Great Comet Crash more than two years ago. The spectrographic data over the past 27 months have tracked an ammonia enhancement after the impacts which was slowly "eaten away" by solar photons but still hadn't returned to the pre-impact level in June of 1996. To actually see the comet haze, clever image processing is required, though: Pre-impact images have to be carefully subtracted from current views. By doing just that two teams had no trouble detecting the remaining material in the UV, also this June: It has by now spread to between 15 and 80 degrees South.

Hale-Bopp's water production rises and rises: Radio astronomers have confirmed the findings from the Hubble Space Telescope (see Update #6) that this comet is producing more water each time it is observed, with the value going up with the -5.8th power of the distance from the sun; just now the value is approaching 10**30 water molecules per second. In contrast the production of carbon monoxide is rising only with the -1.9th power of the heliocentric distance: Water is clearly the dominant driver now.

Second, bigger SPACEWATCH telescope finally under construction: With 1.8 meters aperture it will be the largest instrument in the world dedicated to search for potentially Earth-threatening asteroids. While the mirror was purchased already in 1969, it took a lot of time and effort to raise the money for the telescope and its building (now under construction on Kitt Peak, AZ, next to the old but successful SPACEWATCH camera - 1/4 came from private donations! The new instrument should be able to find 80 000 unknown asteroids each year, most of them in the main belt, but a fraction will be Near-Earth Objects. Around the world the search for them is intensifying now - check this list from a competing Arizona-based program.

More URL's from the Meeting (see Update #6.1) and a correction: The Space Telescope-related online catalogs and sky survey data have moved here recently. An on-line Solar System Data and Ephemeris Computation Service is Horizons. Planetary-research interest groups worth a visit are the Planetary Society and the amateur ALPO. Other places of interest advertised at the DPS'96 were the new efforts for educational programs during NASA missions (POETRY) and SETI, the SEDSAT-1 project and a shop for Space Art.

Update #7 of Oct. 26, 1996 22:30 UTC

Posted from the 28th DPS Meeting in Tucson, AZ, U.S.A.

Stunning HST views: Dust storm on Mars continues

The public will see them only on November 4th, shortly before the Mars Global Surveyor gets launched, but they were already shown at the planet conference here in cold and rainy Tucson: color Hubble images of the planet Mars that show the evolution of a dust storm at high Northern latitudes. The storm was first discovered by Todd Clancy as a brown patch somewhat overlapping the Northern polar cap on Sept. 16th. By October 15th the dusty cloud had mutated into a curly wave which had moved completely onto the polar cap. This is only a minor dust storm which did not affect the global temperature of the Martian atmosphere. Planetwide duststorms, however, can raise the temperature by many degrees, a phenomenon that was last measured in 1995 (only in the radio spectrum, as the planet was virtually unobservable at the time).

For the coming months Mars will be a - relatively - frequent target for the Hubble Space Telescope; 3 to 5 orbits per month will be devoted, which is a lot for a planetary program. But the HST's (and groundbased observers') support is needed for a safe landing o the Mars Pathfinder: It cannot take any close-up pictures of Mars during its approach and requires detailled knowledge of the state of the Martian atmosphere. No major dust storms are likely when it arrives next July 4th, but when the Mars Global Surveyor enters the Martian atmosphere in September, the storm season will have begun. Unfortunately the HST cannot help then: Mars will already be quite close to the sun. Check out this site for the 'use' of Mars in education!

Neptune's changing clouds keeps puzzling astronomers

The planet currently most distant from the Sun is also the most dynamic one: No other major planet keeps changing its face as frequently. When Voyager 2 came by in 1989, a Great Dark Spot was the dominating feature, then it disappeared a few years later, and around 1993 major activity erupted in the Northern hemisphere. When Hubble took its first post-repair images in 1994, there were still many clouds North of the equator, but in 1995 and 1996 the main remaining features were two bands of bright clouds in the South.

The latest images from August 13th confirm this pattern: From 1994 to 1996 the planet has basically stayed the same, at least w.r.t. the band structure - apparently a new stable situation, but markedly different from 1989. In the years before 1989 crude groundbased images had shown yet another distribution of the Neptunian clouds (and therefore apparently also of its bands): One could speculate that the atmospheric pattern switches every 5 years or so. For that reason some 9 HST orbits per year are dedicated to this planet: It is well possible that the Space Telescope will still be around when Neptune does it again...

Other News from the 28th DPS Meeting:

Neptune brighter than ever before! Within the last decades the brightness of the planet has been going up all the time, from 7.82 to now 7.72 mag, while this secular trend was modulated in rhythm with the solar cycle (the more sunspots the dimmer Neptune). Whether both phenomena are really related to the sun is hard to say, but quite a number of phenomena on the gas planets seem to react to the sun, such as the Great White Storms on Saturn and the changes on Uranus which has now much better visible clouds than 10 years ago.

Triton is boring - at least when you observe it with the Hubble Space Telescope: This large moon of Neptune which showed a stunningly complicated and active surface to Voyager 2 is just a totally featureless disk for the HST. But on Pluto - which shares many physical characteristics with Triton - the HST sees a lot (see below): Imagine what this planet might look like for a visiting spacecraft...

Does Pluto's surface change? Given that this planet is just 8 pixels in diameter even for Hubble, it is very difficult to turn images into reliable maps and to compare maps from different epochs. Typical maps have a resolution of about 600 km (with a diameter of the planet of 2300 km), and to obtain them reliably more than one image is needed. The single orbit that was given to Pluto during the Life from the HST program was thus basically useless: The new image from early 1996 does show differences relative to the 1994 pictures, but it is impossible to say whether the pattern of frost deposits has changed in the 2 years or not.

Charon's orbit is excentric: This is a very new discovery coming from the monitoring of the orbit of Pluto's moon with the HST. It is still to early to put a number on the orbital eccentricity, but in the future it might be possible to deduce perturbations by other members of the Kuiper belt.

Saturn's F ring is inclined: Observations of the occultation of a star by this mysteriously warped narrow ring on Nov. 22, 1995, have shown that it is inclined by 0.006 +/- 0.002 degrees against the equator of Saturn. This is the first detection of an inclination in Saturn's rings. The finding explains why the F ring changed its brightness abruptly during the 1995 ring plane crossings.

Update #6.1 of Oct. 25, 1996 23:30 UTC (Oct. 26 16:30 UTC)

Posted from the 28th DPS Meeting in Tucson, AZ, U.S.A.

The "other" Planets: Why are some excentric?

With about 8 extrasolar planetary systems discovered, one can slowly start to look for patterns. One criterion to sort the planets by is their mass, but perhaps the excentricity of their orbits is more important. That's at least what G. Marcy of Lick Observatory is proposing, one of the particularly successful planet hunters.

There seem to be three classes of planetary systems: Those like our own, with a Jupiter-sized object in a Jupiter-like orbit (the only "other" one of this category is the one of 47 UMa), those like the one around 51 Peg, with Jupiter-like objects in very close orbit around their star (in total 4 cases are known to date) - and those like 70 Vir, HD 114762 and 16 Cyg B (see Update #4) with excentric orbits. Tau Bootis is a particularly weird member of class #2, by the way: It is not only very close to its "sun" but also pretty massive (some 4 Jupiter masses). This system must be in total tidal lock, with the star forcing the planet to show it always the same face - and vice versa!

What causes the excentricity in some planetary systems is far from clear, but theorists are busy at work right now. Meanwhile the planet hunt with the most successful technique, looking for periodic patterns in the radial velocities of stars, is continuing. The Lick group has reached the greatest level of accuracy, 3 meters per second - an impressive task, since this means looking for spectral lines moving a mere 1/1000 of one pixel back and forth over weeks to years. But only then can one reliably detect Jupiter-size planets in orbits around other stars. And the hunt for the first other "Uranus" or "Neptune" is already on...

Astronomers still optimistic about Hale-Bopp

While many in the amateur community are increasingly worried about the "performance" of comet Hale-Bopp (which only a few days ago finally broke the 'barrier' of 5.0 mag, according to current observations), comet professionals don't waiver in their excitement. Just take Hal Weaver. The latest spectrographic observations from the Hubble Space Telescope, for example, taken in late September, show the all-important water production rate well on a typical track which would reach 3 to 5 times 10**30 molecules per second at perihelion - almost 10 times the figure that Halley had at the same distance from the sun.

Even more importantly for the visual observer, the dust production which was more or less steady in the last 12 months, has finally started to catch up with the water production - actually Hale-Bopp is one of the most dust-rich comets ever studied in detail! So lets wait and watch: This comet with its BIG nucleus (30 to 40 km in diameter, according to Hubble images with the coma removed) will have more surprises in store. There are for example the half-dozen dust jets which appeared in its coma just when the main driver of the activity switched from carbon monoxide (CO) to water this summer: They basically don't move, which could indicate an outstandingly long rotation period of the nucleus.

So scientists are already having lots of fun with this cosmic visitor: There is the hypothesis, for example, that its nucleus is composed of fragments of different chemical composition. That could explain why the production of carbon monoxide is behaving very differently from the water production (it is flattening out, while the latter is rising and rising). Unfortunately Hubble won't be able to watch, though: From now til next August - when everything will be over (the best viewing window is next March to April) - the comet is closer than 50 degrees to the sun. And that's the limit for the HST...

Galileo Probe solves nagging Shoemaker-Levy mystery!

One of the many unsolved questions that the Great Comet Crash of 1994 left behind was the nature of the amazing circular rings that emanated from every impact spot and just moved on without slowing down. This indicated that some wave phenomenon (and not the actual transport of matter) was to blame - but what kind of wave? Based on the models of the Jovian atmosphere available in 1994 and 1995, Andy Ingersoll had figured out that only one special kind of wave at great depth could possible have the right speed (of 450 meters per second) - but only if Jupiter was extremely rich in water.

The Galileo Probe, of course, found the opposite, an extremely dry Jupiter, at least in the Hot Spot region that it accidentally fell into. While the debate is still raging on how global the dryness of Jupiter really is (and whether the "missing" water can't be hidden somewhere, e.g. in the thunderclouds Galileo has imaged North of the Red Spot or other phenomena), a clever Japanese - working at the National Research Center for Earth Science and Disaster Prevention, of all places - may have solved the mystery.

Shingo Watada has taken the new atmospheric profile data that also came out of the Galileo Probe mission and calculated the sound speed at various heights. And there it was: a "trap" for soundwaves between the 1 bar level of the atmosphere and 300 km above it that had not existed in the pre-Galileo atmosphere model! Sound waves from the impact explosions could have travelled inside this channel, being reflected up and down and thus slowing their actual horizontal speed to some 500 m/s: just right to explain the larger, outer wave. Moreover these sound waves would have existed at the right altitude where the dark material actually condensed that made the rings visible in the first place.

Some URL's discovered at the DPS Meeting:

Try out counting craters on Jupiter's moons or join groundbased observers monitoring them - or relive the adventures of observing Jupiter in daytime in support of the Galileo mission.

The Stardust mission to a comet has a newly designed homepage as has Science magazine (which devoted its Oct. 18 issue to many papers on the Galileo orbiter). And you can also watch the new Palomar Sky Survey in progress or observe stellar occultations by asteroids. [Listing corrected; see more in Update #8]

Update #5 of Oct. 24, 1996 02:40 UTC

Posted from the 28th DPS Meeting in Tucson, AZ, U.S.A.

Daylight Fireball over the Netherlands!

The following report has just come in from Casper ter Kuile from the Netherlands: "Dear observers! As previously stated by Urjan Poerink of the 'Dutch working group meteors' a daylight fireball has been observed from the eastern and northern part of the Netherlands. Our well-known meteorologist Jacob Kuiper from the National Meteorological Weather Service (KNMI) has gathered lots of observations regarding this event. It might turn out that this fireball could well be a meteoritedropper!

From a number of observations we are able to conclude that this fireball appeared above Germany (Niedersachsen, Schleswig-Holstein, Mecklenburg-Vorpommeren), Denmark or the Baltic sea. The uncertainty is rather big still.We urgently ask our German and Danisch colleagues to pay attention to this special event! Dutch meteorobservers of the DMS and WGM will join efforts in an interviewsession this weekend in the north-eastern part of the Netherlands to gain more knowledge on the trajectory of this very special event. Sorry, I forget to mention the date of this big bright daylightfireball. October 17, 11:35 UT."(2 Circulars from late Oct. 23 and early Oct. 24, 1996)

Meteorite-travel from Mars to Earth? No Problem!

It has been known for some time that meteoroids can travel between the planets (see e.g. Gladman et al., Science March 8, p. 1387-92) - and now there a full computer simulation of what can happen when an object is "launched" from Mars (as the consequence of a large impact). Several workstations around the world integrated the highly chaotic trajectories of thousands of test particles: First, they stay in the vicinity of Mars, then their orbits get increasingly disturbed, and finally they crash into Venus (7% of all cases), the Earth (another 7%), Mars (9%) or the Sun (32%). About 10% reach Jupiter and get thrown out of the solar system, and the remaining 35% 'survive' for millions of years.

The 'trip' from Mars to Earth can be very quick if the meteoroid gets launched with a high speed and in the right direction: perhaps one in 10**8 goes even on a direct 6-month trajectory to Earth. Since some exobiological experiments have shown that primitive life can withstands many months of exposure to space if it is protected by some meteoritic crust, it is rather likely that any life which may have arisen on Mars would sooner or later end up on Earth! The other way around would be much rarer: The gravitational field of the Earth is much greater than Mars', and there is also the atmosphere which hampers any 'launch attempt'. (Talk by J. Burns at the DPS-Meeting)

Io has a high-altitude ionosphere

Scientists participating in NASA's Galileo mission have discovered that the Galileo spacecraft may have flown though a dense, high-altitude ionosphere during its encounter with Jupiter's volcanic moon Io last December. This discovery suggests that Io's atmosphere is time variable and is made of volcanic gas lofted to very high altitudes. Plasma Science sensors on the spacecraft found a very dense region of ionized oxygen, sulfur and sulfur dioxide at 555 miles on Io that obviously was pumped into that region by Io's volcanic activity. Instead of being swept away by Jupiter's rotating magnetosphere as anticipated, the ionized gases surprisingly remain with Io.

Passage of the Galileo spacecraft through an ionosphere was not expected because images of the volcanic plumes previously taken with the Voyager spacecraft indicated that the plume heights extended only to a few hundred kilometers or less. A radio occultation by the Pioneer 10 spacecraft in 1973 indicated ionospheric heights only about 30 to 60 miles above the surface. No one expected to see this at 900 kilometers' altitude. The difference between what Pioneer saw and what Galileo has observed indicates that Io's atmosphere and ionosphere are variable and may grow and shrink with more or less volcanic activity. (adapted from NASA News # 216 Oct. 23, 1996)

Other News from the 28th DPS Meeting:

Lunar Transient Phenomena near edges of maria: A comparision of these strange flashes on the moon (which have been reported for at least 450 years) with the new geologic maps of the moon generated from Clementine's images is indicating some possibly revealing correlations. Not only is there a concentration of "LTP"s near the edges of maria; the reported events also tend to be in craters with rims of distinctly bluer composition. This compositional difference may have resulted from recent slumping of the rim, accompanied by the appearance of fresher underlying material. The LTPs may thus be associated with outgassing of volatiles collected in mare basalts.

Clementine's Moon map delivers new quality: With the help of this little lunar mission from early 1994 the cartographic control net for the Moon has been improved from 1-2 km on the near and 10 km on the far side to better than 200 meters globally. Several automated procedures were developed to aid in finding matchpoints, with a successrate exceeding 90%: This software is available on the Internet.

Plans for a 4 meter coronagraph useful for both solar and other astronomical studies are currently being drawn: CLEAR or the Coronographic & Low Emissivity Astronomical Reflector would be an obstruction-free off-axis Gregorian with 0.1 arc sec resolution and probably some adaptive optics. It could revolutionize the study of the exospheres (extremely thin outer atmospheres) of the Moon, Mercury and Jupiter and could look for asteroidal satellites (which some simulation say are frequent). And in the distant Universe CLEAR would be ideal for imaging the halos of galaxies.

Update #4 of Oct. 23, 1996 23:55 UTC

Posted from the 28th Annual Meeting of the Division for Planetary Sciences

of the American Astronomical Society (DPS) in Tucson, AZ, U.S.A.

Yet another Planetary System - again no twin of our own

One year ago most astronomers would have proclaimed that our own Solar System would be typical, and computer simulations had underpinned that idea. But each and every other planetary system that has been discovered in the last 12 months looks different - and the newest case is no exception. Announced just an hour ago here at the world's largest planetary science conference, the planet of 16 Cygni B has a mass of equal or greater than 1.5 times that of Jupiter and a semimajor axis of 1.7 AU. But unlike other Jupiter-sized planets in near-circular orbits of the order of one 1 AU that circle 47 UMa and Lalande 21185, this one has a large excentricity of about 0.7!

The reason could be that 16 Cygni is a double (or even triple) star, albeit a strange one: The components A and B move around one another every few 100 000 years on a very excentric orbit (e = 0.90...0.95) with a semimajor axis of some 4000 AU and a periastron of a mere 200 AU. Right now the two stars (which are about 70 light years away) are separated by 33 arc sec or 700 AU: their last close approach took place just a few thousand years ago. The third component, by the way, is 7 magnitudes fainter and stands 70 arc sec away.

It may well be the double nature of 16 Cygni that has 'pumped' up the excentricity of the planet's orbit. On the other hand it might be typical that planets born in double stars start out on excentric orbits to begin with. Or there is yet another mechanism at work that none has thought of yet. Whatever the reason: Although 16 Cyg B is a near-perfect twin of our Sun (with 1.00 +/- 0.05 solar masses and a temperature identical to the first 3 digits), its planetary system clearly isn't. (Press conference by W. Cochran on Oct. 23, 1996, at the 28th DPS Meeting, who is one of four discoverers, working in two totally independent teams)

Other News from the 28th DPS Meeting:

The News from Mars is... No News: That's the state of the quest for evidence for (past) life on Mars. Several members of the Houston-based team that caused such a stir two months ago, including Dave McKay, gave presentations today to both the media and the scientific community - but no new evidence was presented. To the contrary, actually: McKay all but retracted his earlier comments on possible life traces in a 2nd Martian meteorite (see Update # 2) which he now considers "so shaky we don't want to talk about it", and he didn't elaborate on the evidence for cell walls in some of the tiny structures in ALH84001 that he had mentioned in a House hearing on Sept. 12th.

The plan is now to get even thinner cuts of samples of the meteorite for TEM analysis and to try looking for biogenic traces with light fluorescence microscopy. Otherwise McKay et al. have been busy responding to a flurry of critical letters Science has received in recent weeks (which will be published soon) and to study many samples of extremely tiny structures in terrestrial stones that some interpret as nannofossils or nannobacteria. In his talks McKay showed strikingly similar structures from the Earth and from Mars - even if the "Martian fossils" might turn out to be some inorganic artefacts in the end, the current activity would have brought forward micropalaeontology on Earth a great deal.

The Great Red Spot's center is counterrotating! This is one of the many puzzling findings from Galileo's early orbits around Jupiter. The understanding how this gigantic storm is structured in 3D has grown quite a bit, thanks to Galileo's visible and especially IR images, but why it acts like it does, remains to be studied. Meanwhile the first images from the 2nd encounter (Ganymede-2) have become available.

Can Hyakutake's X-rays be explained by dust? According to a new model the strikingly bright X-ray emission that ROSAT saw from this comet (and lots of others in the past) could be solar X-rays scattered by extremely small dust particles of just 5 nm scale. This can explain the intensity of the cometary x-rays quite well - but how would one account for the fast variations of this intensity that were measured and did not reflect variations in the output of the sun?

Update #3 of Oct. 21, 1996 23:45 UTC

Posted from Tuscon, Arizona, U.S.A.

The Meteor(!) that came twice!

This could well be the most unusual meteoritic event that hit the Earth since Tunguska: A meteoroid about the size of a car first grazed the Earth's atmosphere, causing a spectacular fiery display over much of the Western U.S., then left the atmosphere again but reentered one orbit later and crashed into California.

At least that's the story that astronomers have figured out from the available visual observations from Oct. 3rd: The interval between the two sightings was 100 minutes, equal to one Keplerian orbit of the Earth at low altitude, and the distance between the original path across the sky in New Mexico and Texas and the later track seen in California is 25 degrees of longitude, exactly the amount the Earth has rotated onwards in these 100 minutes.

Now a reward of $U.S. 5000 is being offered for parts of the meteoroid that could have reached the ground in California. This event, while unique, somewhat resembles the famous fireball of Aug. 11, 1972, which was also caused by a meteoroid grazing the outer atmosphere and then returning into space. But this one never returned, although some predict it might do so next summer. (The Arizona Republic Oct. 19, 1996)

Really Live Images from Mars on the Internet

That's what NASA is promising for the upcoming Mars Pathfinder and Mars Global Surveyor missions. The old rule that the data from space missions, including images, "belong" to the mission scientists for some time, with only selected bits reaching the public at their choosing, is being rapidly eroded these days. In contrast to the on-going Galileo mission where the slow trickle of bits from Jupiter hampers efforts to make full images available right away, the new Mars mission images will be piped into the WWW as soon as possible!

While there may still be some delay in the case of the orbiting Surveyor, the images from the IMP (Imager for Mars Pathfinder) instrument will reach "viewers" on the Internet at the very moment they appear on the monitors of JPL - that is, if both the launch on Dec. 2nd and the touchdown on July 4th, 1997, are successful. And not only images but also daily weather reports will be available from the lander: Together with efforts to bring the Mars news to Earth big style (in the " Life from Mars" program) this will be a completely new Martian experience... (Mesa Tribune Oct. 17, 1996)

A Martian visit for Deep Space One?

The Deep Space One spacecraft, the first in the new New Millennium series of NASA technology demonstrators, will not only visit an asteroid and a comet but will also make a - moderately - close flyby of Mars, which just happens to be in the right place. After launch in July of 1998, DS1 will encounter asteroid McAuliffe on Jan. 28, 1999, Mars on April 19, 2000 and comet West-Kohoutek-Ikemura on June 6, 2000. Interestingly DS1 cannot approach Mars arbitrarily close because there is a legal 'zone of avoidance': If you want to get closer you have to sterilize your hardware, and New Millennium doesn't want to pay for that.

The instrumentation of Deep Space One (which will travel with the help of an ion engine, the first ever to go on an interplanetary journey) has already been chosen. There will be a combined camera and spectrograph as well as fields & particles instruments. But science really isn't the main issue for this mission: Even if DS1 just flies but doesn't report one bit of science data, it would still be considered a full success, technically. However, in order to enhance the science output, there will be a team of small body experts on hand to optimize the camera and operations. (On Location at the Arizona company that builds DS1; with additional insights from JPL: D. Fischer)

Update #2 of Oct. 15, 1996 12:50 UTC

Famous German Institute faces Closure!

It came as a shock to the space science community in Germany: One of their most important institutes, the Max Planck Institute for Aeronomy will most likely be closed within the next few years. Many past, present and future endeavours of Europe's space science were and are based here, e.g. the cameras of the comet spacecraft Giotto and Rosetta or a major spectrograph of SOHO. Between 1994 and 2000 the Max Planck Society has to lay off 11% of its staff in the Western Bundeslaender, to make up for funding shortages and heavy investment into the East (i.e. the former GDR).

The policy of the society is to kill whole institutes instead of laying off a few people everywhere: This is supposed to keep the 'survivors' competitive. Fortunately the MPAe is the only victim in the field of physics, chemistry and technology. The decision to close it down has still to be confirmed by the MPG senate in November; the future of the science programs run from there is totally unclear at the moment. (DF, based on an interview with a high-ranking MPG officer)

Rosetta loses one of its landers

Bad news galore for Europe's space scientists: A sudden decision by the Jet Propulsion Lab to withdraw its funding for the Champollion comet lander has killed this joint venture between France and the U.S. Champollion was supposed to accompany the German-led RoLand on the Rosetta spacecraft to comet Wirtanen.

Now RoLand will be the only surface science package of Rosetta, maybe a little bigger than planned: The French are scrambling to get some of their instruments aboard. The U.S. comet community, though, has been had once more: First they don't get their Halley Intercept Mission, then they loose CRAF, and now Champollion. The Deep Space-1 mission to comet West-Kohoutek-Ikemura and the Stardust mission seem to be healthy, though - and there is talk of a Deep Space-5 mission which would basically be a Champollion without an orbiter. (DF, based on interviews with various Rosetta people; see also Nature of 10 October, page 469)

Suspected fossils in other Martian meteorites

The researcher who brought you the "evidence of past Martian biota" in the famous meteorite ALH84001 from Mars have now found similar microstructures resembling microfossils in at least one other stone from Mars. If this is confirmed and the fossils in both ALH84001 and the other Mars meteorite(s) turn out to be genuine, the likelyhood of present life on Mars would rise dramatically. This is because ALH84001 is 4 billions years old, while the others all date back only some 1.3 billion years. So if there was (microbial) life on the Read Planet in its infancy and billions of years later, there would be every reason to believe that it survived until today.

Dave McKay, who leads the investigation, had already earlier expressed his belief in the power of Martian life: Once started, he told the Space News it would always find warm places to cling on. (CBS [Evening News] 11 October) Later he somewhat retracted his comments to CBS and is now speaking of only "very preliminary evidence" for fossil evidence in the younger Martian meteorites.[2: 96/10/15]

Briefly noted:

Solar eclipse major success: Many European countries enjoyed their best partial solar eclipse in years, and public observatories had a field day with 1000's of visitors. But the media coverage of the eclipse was also a bleak reminder of the staggering incompetence of average news people to deal with astronomical events: The "recommendations" for safe observations given by various German TV stations ranged from the bizarre to the outright dangerous...

Mass of the Galactic Center nailed down: The clever use of modern speckle imaging techniques in the near infrared has finally allowed the measurement of proper stellar motions in the vicinity of Sgr A*, the mysterious central object of our galaxy. Combined with radial velocity measurements it is now clear that the stars are on simple Keplerian orbits around a central point mass of 2.5 +/- 0.4 million solar masses. The likelyhood that Sgr A* is a massive black hole has thus increased, though the high mass alone is not a definitive proof. (Nature 3 October, page 415-7)

Update #1.3 of Oct. 10, 1996 19:00 UTC

Physics Nobel Prize with Cosmological Implications

This year's Nobel Prize in Physics for the discovery of superfluid helium, i.e. events at extremely low temperatures in the laboratory, is nonetheless something astronomers should take note of: There are parallels to events which may have taken place in the very early Universe and led to the formation of topological defects such as cosmic strings. Find out more anout the Nobel Prize in Physics 1996 from The Official Announcement of the Swedish Academy, Lots of Pages from the Cornell University, or A detailled directory of physics laureates.

Anti-gravity engine working, held under wraps?

Apparently a Finnish experimental paper that describes a magnetic engine which reduces the weight of everthing placed above it by 2% was first accepted for publication by the prestigious Journal of Physics D - and then withdrawn. Now everybody is wondering: Was "Podkletnov's antigravity device" a joke from the beginning - or was the paper withdrawn because it actually worked so well that it was to be patented first? (New Scientist 21 Sept. 1996 7) Some more notes on these weird events can be found - albeit on a website from the science fringe...

Planetary researcher predicts Mars-sized planets beyond Pluto

Why is there almost no mass beyond the orbit of the planet Neptune? Even the planet Pluto, thousands of "Kuiper Belt Objects" in the size range 100 to 400 km, and billions of cometary nuclei don't add up to more than one earth mass - while some 50 earth masses might be expected in the range 50 to 75 astronomical units beyond Neptune's orbit. That there is so little mass in the range 30 - 50 AU is easy to understand, given the strong gravitational influence of Neptune. But beyond 50 AU observational data are pretty scarce and any planet even of substantial size (comparable to Pluto or even Mars) would be well hidden in the "twilight zone" - and could nonetheless be discovered within the next few years, thanks to advances in widefield imaging. (Talk by A. Stern, SWRI, in Bonn, Germany, on Oct. 10, 1996)

Deep Partial Solar Eclipse coming to Europe!

The deepest partial eclipse of the sun (not a total one, unfortunately) can be seen all over Europe on the afternoon of Saturday, Oct. 12th - and the weather forecast, at least for Germany, is excellent. Detailled information plus live pictures of the eclipse will be available from the Society for Popular Astronomy in the U.K., while the European Southern Observatory has thought about didactial experiments the eclipse could be used for. And there is always Sky & Telescope.

Briefly noted:

Still no Galileo images from the Ganymede-2 encounter more than a month ago have been released by the JPL - it's about time! Keep your watch on The Galileo Homepage for any new developments.

Two comets of 5th magnitude can be seen in the sky, Hale-Bopp in the evening at 5.2 to 5.6 mag (falling more and more behind even conservative predictions...), and Tabur all night long in UMa at 5.0 to 5.6 mag (all estimates from Oct. 7 til 9th). Both comets have faint tails: Follow their development in the sky and on a special page for comet observations.

Big planet conference ahead: The 28th Annual Meeting of the Division for Planetary Sciences of the American Astronomical Society will take place in Tucson, AZ, from Oct. 23-26 - expect several important announcements (which I already have, but which are embargoed until the 23rd - sorry). Abstracts are available. If technology permits, The Cosmic Mirror will 'broadcast' live from the conference.

Compiled and written by Daniel Fischer (send me a mail to!), Skyweek