The Cosmic Mirror

of News events across the Universe

Winner of the and in 1997!

Daniel Fischer is also the 1997 winner of the
Bruno-H.-Buergel-Preis of the Astronomische Gesellschaft

Also check out Astronomy Now's Breaking News and Florida Today's Online Space Today!
Current mission news: Pathfinder (DLR) + MGS (science!) + Cassini + Galileo

Cassini on its way to Saturn!

An interesting footnote to the debate and protests about the safety of the radioisotope batteries: A local newspaper put a Cassini representative (Steve Edberg, well known to amateur astronomers from his time with the International Halley Watch) and a leading protester at a table and had them debate for four hours.

Now the focus is finally on the mission itself - which starts with 7 years of "cruise", leading to a dramatic arrival in the Saturn system. Funding shortages have led to the sad decision to forgo any scientific observations during the Venus and Earth flybys or to visit any asteroid enroute, like Galileo did. However, after the 4 year baseline mission in orbit around Saturn as well as the Huygens probe mission are finished, an extended mission is thought possible.

Briefly noted:

The Mars Global Surveyor has temporarily halted its aerobraking after strange things happened to the misaligned solar array (which at first had been pushed almost into the correct position!). And the MGS is also delivering preliminary Martian science data, including a new image!

Mir finally jettisoned the old Progress ship, making room for the new cargo craft already launched. And Atlantis is back - after having probably located the main leaks of the Spektr module when bursts of air were pumped in and debris floated out.

NASA has selected two new Small Explorer missions: HESSI (launch in 2000) will study flares on the Sun, GALEX (2001) galaxies in the UV. In case one of these missions runs into severe development trouble, BOLT could study gamma ray bursts. And there might also be a TWINS mission with two satellites taking 3-D images of the Earth's magnetosphere.

The 50th anniversary of the 'breaking of the sound barrier' on Oct. 14, 1947, has been celebrated widely - the first supersonic flight set the stage for the U.S. space program. Only one day before the anniversary Thrust SSC broke the sound barrier on the ground as well - but this time spin-offs for the rest of us are less likely...

In a nutshell: The - probably - most luminous star known has been imaged by Hubble's NICMOS camera, causing some excitement (and note the 55537 degrees C - what a precision... :-). / A bright meteor over Texas was seen in broad daylight on Oct. 9th. / A new large robotic telecope will become available in 1999.

A current picture of Hale-Bopp still shows jet activity. / The planned test of the MIRACL laser gun has been cancelled - perhaps forever. / Temperature measurements from space are important for climate studies. / And the HET telescope has been inaugurated.

First MGS Mars close-ups published!

Most of the images are of relatively poor quality, as the MGS spacecraft is not yet in the orbit for which the MOC was designed - and still the views are quite dramatic! Two of the best images have now been released in several versions, along with "context" frames derived from Viking Orbiter images. And even this ist just a sneak preview: MGS has been using atmospheric drag to reduce the size of its orbit for the past three weeks, and will achieve a circular orbit only 400 km (248 mi) above the surface early next year. Mapping operations begin in March 1998. At that time, MOC narrow angle images will be 5-10 times higher resolution than these pictures!

Mir/Atlantis EVA successful; new Mir computer installed

Meanwhile the launch of the first components of the ISS is only 9 months away, and all 15 nations involved in the giant project have just finalized the assembly sequence: the FGB and Node 1 will be launched in June and July, the Service Module in December, 1998. Most important for Europe: Columbus goes already in October, 2002. No longer around to celebrate it, however, will be the German space agency: DARA ceased to exist Oct. 1st and is being re-integrated into the German Aerospace Research Establishment (DLR).

Ariane 5: Second launch attempt slipped to late October

Briefly noted:

Following a special attitude change the Canadian RADARSAT is now observing Antarctica as no radar satellite could do before. The aim is to study changes to the ice cover of the continent.

The Lewis satellite was destroyed when it re-entered the atmosphere on Sept. 28th - contact to the experimental Earth observer had been lost soon after launch when a mis-firing thruster spun up the satellite.

In a nutshell: Future small missions to comets are reviewed here. / What Earth would look like as a Black Hole and related relativistic ideas have been studied in Austria where the results were presented at the annual Meeting of the AG in Innsbruck. / New images from ISO have been published as has been a new HST image of Betelgeuze (with a remarkable hot spot at one rotation pole). / And you can follow the development of the current El Nino from space.

Cosmological distance of GRB's proven?

MGS: Mars has a magnetic field

Briefly noted:

Yet another solar-terrestrial event is under way but NASA says, do not fear... Detailed documentation about the rivers of plasma inside the Sun can be found at Stanford, more on helioseismology learned from GONG and HiDHN.

Shuttle mission STS-86 is under way, close to docking with Mir - never before had the fate of a misson hung in the balance hours before liftoff, but Goldin declared Mir safe for a visit, following independent advice.

In a nutshell: Hale-Bopp is back in the news after a successful observation by Hubble, and there is more to report. An excellent collection of images has also turned up. / Pictures of the lunar eclipse of Sept. 16 have been published by ESO, Austrian students and ... well, see for yourself :-) / A high resolution map of the Earth has been created by the USGS. / The HST has found an isolated neutron star. / And great Earth images from SeaWIFS have been released.

Mars Global Surveyor safely in orbit!

The IAU Circulars are now on the web

The user surface is still somewhat confusing, but give it a try: Click here and enter the number 6743, then hit enter. This should give you a circular issued on Sept. 13th; on the top and bottom of the page you can click to further releases. There are even some historical issues available: Try "1" for the latest news - from 1922. Or enter "5000" for the famous IAUC on the launch of Hubble. The Cosmic Mirror congratulates the Central Bureau for Astronomical Telegrams and the IAU Comm. 6 (which oversees the CBAT) to its bold decision!

Briefly noted:

The launch of Cassini is being delayed to at least Oct. 13 because the Huygens probe has been damaged in late August. At this time Cassini and Huygens had just been mated to the Titan rocket, to which they have returned after the successful repair of the torn Huygens insulation. The heated debate about the safety of Cassini's RTGs is continuing, however, with sometimes bizarre claims being made. One radical Munich city council member, e.g., claims that after a launch failure of Cassini everyone on Earth would die...

News Capsules: The launch of the Lunar Prospector has been delayed to Nov. 23. / Hubble has discovered a huge crater on asteroid Vesta and amazing UV effects around a galactic central region. / The 99th launch of an Ariane was a success; on board were Eutelsat Hotbird 3 and Meteosat 3. / The Pentagon is pondering an anti-satellite laser test. / New ISO Images of the Hubble Deep Field have been released. / The FORTE s/c has been launched on Aug. 29th. / And new SOHO results shed light on the inner workings of the Sun.

Lewis and ACE launched; Lewis in trouble

More luck for the Advanced Composition Explorer (ACE) which was launched on August 25th. This spacecraft will be stationed in a Lagrangian point between Sun and Earth and study the composition of the solar wind with nine instruments. And yet another launch of a small satellite is imminent: FORTE, for Fast On-orbit Recording of Transient Events: It is an advanced radio frequency impulse detection and characterization experiment. Emphasis is on the measurement of electromagnetic pulses, primarily due to lightning. The Pegasus lauch is set for Aug. 28th.

Sagan Station, Sojourner still going strong after 50+ days

During the first 30 days about 1.2 Gbit of data were returned, including 9669 IMP and 384 rover camera images as well as 4 million weather measurements: The amount of data is twice than was was hoped for! New pictures were published today after a lengthy gap. The only instrument from which new information is slow in coming is the APXS - here lengthy recalibrations in the lab are necessary to get rid of the surprisingly strong influence of Mars' thin atmosphere on the soil and rock spectra. Eventually all information will be retrieved.

Meanwhile the Mars Global Surveyor is closing in on Mars - you can follow the progress in the current status reports. Most interesting news at the moment> the collection of images taken during approach has grown with three views from August 20th (also discussed here). So the MGS is already 4 times as successful as the Mars Observer which obtained precisely one Mars image... :-) For other funny aspects of Mars check out what Hollywood made of it.

And the Hubble constant is ... 73, really!

All those galaxies are mere stepping stones, though: They are 'used' to calibrate an amazing number of secondary distance indicators which then extend the distance scale to distances large enough to measure the more or less pure Hubble expansion of the Universe. The 73 value - which first surfaced in the spring of 1996 - has grown more stable in the past year, and when the project finishes in 1998 all bets are that the 'real' value of Ho will be in that vicinity. What does all that mean?

Not much, unfortunately! If the density of the Universe were closed to the critical one, Ho=73 would mean that the age of the Cosmos is just 9 Gyr (10**9 years). That would be a clear contradiction to the established ages of the oldest stars and would call for a modification of the standard big bang model, probably by introducing the cosmological constant (want more math? :-). But if the density of the Universe is low, as many observations suggest, then the age of the Universe could be close to 12 Gyr, and may be marginally consistent with the oldest stars... (The Sidereal Times, newspaper of the 23rd General Assembly of the IAU, # 5, Aug. 22, 1997, p.1)

Briefly noted:

Discovery observed Hale-Bopp: After its on-time launch and deployment of CRISTA, a German atmosphere research satellite, the crew found some time for astronomical observations: Here is more about this SWUIS experiment, and here are some Hale-Bopp images! The shuttle returned on Aug. 19th.

Meanwhile the new Mir crew succeeded with the the crucial spacewalks: On August 22nd the cosmonauts had no trouble reconnecting the Spektr solar arrays and inspecting the module's interior, though powering up Mir is a slow process. As expected the small breaches in Spektr's hull were not found from the inside - all hopes are now focused on a spacewalk on Sept. 3rd. In Russia preparations for an actual repair operation in October are underway, but even if reparing Spektr fully turns out to be impossible, the challenge alone would be a major learning experience for future ISS operations, the U.S. and Russian partners agree.

News Capsules: For the first time, Fluor has been found in interstellar space. A disk around a young star has been found in the radio by planetary discologist V. Mannings. A new instrument for Hubble has been selected, to go up in 2002.

Find out how strange is the universe and how old ist it? Watch Hubble split Mira or how the first 8.2-m telescope for the VLT takes shape. A new telescope for the South Pole has been delivered, while NASA scientists dream of building a warp drive.

The Heaven's Gate folks are back; fortunately there are still skeptics around. Another weird idea by R. Hoagland has been smashed! Have you ever wondered how to make money from asteroids? And you can help find the real aliens! And finally, look at a raw image of the Earth in the UV with an apparent 'mini-comet' disintegrating, to be found near the end of the new version of the Small Comets FAQ.

Comet Mysteries: one solved(?), two remain

The analysis of the flood of observations has just begun. Some results came fast, such as the discovery of molecules never seen in comets but now readily detected esp. in the sub-millimeter range (such as HCOOH, HNCO, HCCCN, H2CS, SO, SO2, HCO+, NH2CHO and CH3OCHO). Other molecules seem to have been detected, but are not yet identified. And understanding the temporal behavior of the production rates is another challenge: There could be indications of an inhomegeneous structure of the comet's nucleus, either a relic of its formation or the product of past perihelion passages of Hale-Bopp. Three of the major comet puzzles of 1996 and 1997, however, were

• the "gas arcs" in Hyakutake's inner coma, imaged especially well by the WIYN telescope (look at the March 25 images!). There are still several competing theories how these structures were formed, whether secondary nuclei (that split off the main nucleus) and/or shock features were involved.
• the neutral sodium tail of Hale-Bopp, discovered in April of 1997 (see also Update #53). There are by now at least six different ideas where the sodium (Na) came from (the nucleus, the coma, the dust tail, an invisible special dust tail(!), the plasma tail...) and how it got out to the distance where it was sighted, but none of the models is strong.
• Basically solved, however, is the origin of the X-rays from comets: The proposal that heavy ions in the solar wind get their electrons back in the coma and happily emit some high-energy photons in the process (see Update #47) has gained wide acceptance. The only competing idea (solar X-rays reflected by extremely small dust particles, "attodust", in the coma) was withdrawn at the conference by its main proponent! (Talks at the conference by Weaver, Krasnopolsky and others)

Briefly noted:

Pathfinder has discovered its own backshell!

Other news from the press conference:

• In order to reconfigure the ageing batteries of the lander it will be turned off overnight in a few days. But the scientific operations should continue for months afterwards and will only be affected marginally. The Pathfinder meteorologists are particularly interested in operations continuing for many more months: In about one (Earth) month the climate should start changing.

• The automatic operation of Sojourner, when she is just provided with waypoints and a target to go to, is working wonderfully, and the rover has already travelled quite a distance around the lander and traversed several small obstacles. One reporter was so impressed by a VR representation of Sojourners journey that he actually wanted to buy the system for his car... :-)

• And the Pathfinder IMP team stands by its statement that the opacity of the sky is a constant 0.4-0.5 - the HST analysis arriving at significantly lower values must be in error (it is difficult). Looking skywards IMP is seeing lots of structure in the (water-ice) clouds, sees them moving, and has imaged beautiful sunrises and sunsets. However, the 'pale blue dot', out Earth, was behind clouds when its picture was to be taken. (via NASA Select TV, courtesy of the MIT and the DPS Press Officer, July 31, 1997)

Redshift 4.92: New cosmic distance record set!

The results show the young galaxy is as far as 13 billion light-years from us, based on an estimated age for the universe of approximately 14 billion years - or insert its redshift of 4.92 into your favorite cosmological model (at such a high z value distances and ages depend critically on the adopted values for the Hubble and cosmological constant and so on).

In any case the high z places the galaxy far back in time during the "formative years" of galaxy birth and evolution, less than a billion years after the birth of the universe in the Big Bang in some world models.The detailed image shows that bright dense knots of massive stars power this object. Due to the firestorm of starbirth within it, the galaxy is intrinsically one of the brightest young galaxies in the universe, blazing with the brilliance of more than ten times our own Milky Way. (adopted from STScI PR #25 of July 30, 1997)

And again: "microfossils" in a meteorite claimed...

The object in question is a rare type of space rock called a carbonaceous chondrite. Carbonaceous chondrites are unusually rich in water and carbon compounds, the atomic building blocks of living organisms: they also contain a surprising number of other organic molecules, and have peculiarly low density. No one was sure where the Australian carbonaceous chondrite came from - certainly not from Mars. It has a composition similar to that of a large asteroid, Ceres, and of Phobos, one of the two moons of Mars and possibly a captured asteroid.

The announcement at a major SPIE conference has been greeted with even more scepticism than the 'Mars meteorite' claims one year ago: There, at least, the NASA scientists had several lines of evidence and not just some electron microscope images. And one should not forget that microscopic evidence alone has led to various 'life signs in meteorites' claims over the past 30 years - none of which was ever confirmed... (San Francisco Examiner July 31, 1997)

Who's still believing in 51 Pegasi?

Grays conclusions center on the temporal behavior of the so-called spectral line bisector curvature of 51 Peg: The star's spectral line shape changes over time in a manner very characteristic of stellar oscillations. One can make up a model with gravity mode oscillations of 51 Peg's surface that reproduce the line shape changes almost perfectly. At least five groups of researchers are now waiting for the next good observing wind of the star (coming up this fall) and will throw the latest of spectroscopic technology at 51 Peg.

Gray, who as a purely 'stellar' astronomer has no stake in extrasolar planet research, made it clear that he only dismisses this one particular case. He has no problems with many other extrasolar planets reported for other stars, especially when the radial velocity amplitudes are really large. And Cochran reminded the audience of many other stars that show radial velocity effects looking like planet effects but which are known to be intrinsic pulsations. Even for the pulsating star, Delta Cephei, a companion was once claimed... (July 31, 1997)

Briefly noted:

Further upgrades to the NEAT asteroid hunting system should make it possible to find more than 75% of all potentially Earth-threatening ateroids larger than 1 km within the next 10 years (and almost all of them by 2015). Just working temporarily with one camera the system has found an amazing number of asteroids, and two more cameras will probably be mounted to two other similar air force telescopes. So far the astronomers are only guests there (on 1-year contracts), but their cameras are so much better than the military ones that there are now plans to keep them installed permanently and to use them both for asteroid hunting and satellite tracking. (News conference at the conference by E. Helin, July 30, 1997)

The opacity of the Martian atmosphere is still not clear (no pun intended): The analysis of frequent HST observations of Mars' clouds and dustiness still yields values significantly below those reported by the Pathfinder IMP camera team. E.g. on July 9th the optical depth from dust in the Pathfinder area was found by Hubble to be about 0.2, with hardly any noticable clouds. The 20-30% discrepancy is unresolved. (News conference at the conference by P. James, July 30, 1997) Meanwhile Sojourner got stuck but is free again while it continues to circle the Sagan Memorial station. (Florida Today July 31, 1997)

Hale-Bopp's sodium tail remains a mystery: There are many attempts already to explain the phenomenon, ranging from the neutralization of ions in the plasma tail over a gas source at or near the nucleus to four different gas production processes possible in the dust tail. The neutral sodium (Na) abundance actually increases. down the tail - and the position of the Na tail relative to the ion and dust tail changed at least once from March to April. (News conference at the conference by J. Wilson, July 31, 1997)

Another astronaut will fly to Mir this September than was planned: David Wolf will have so serve as a back-up for spacewalks and has to fit into a specific kind of spacesuit - what Wendy Lawrence doesn't. (NASA News July 30, 1997) Meanwhile Mir commander Tsibliev has said in an interview that he is not only innocent of causing the dangerous Progress crash in June - but that his steering skills actually avoided a deadly crash of Progress into the Mir core module... (CNN Online July 30, 1997)

We almost understand Jupiter's Europa

What we know about Europa from detailled Galileo observations and theoretical modelling is

• that Europa is internally concentrated like the Earth, with a 150 km thick layer of H20 (in what ever state) above a silica mantle and an iron core. Whether Europa has a magnetic field is not clear, however; there could be a weak dipole, tilted 45 degrees against the rotation axis (which would be rather unusual);
• that Europa's crust is decoupled from the core (be it by an ocean or just ductile ice), which leads to specific stress patterns in the crust, in addition to tidal stresses. It is now possible to derive relative ages of Europa's band-like surface features (in the near infrared they get brighter the older they are), and their global pattern rotates in a characteristic way over geologic timescales;
• and that the famous 'triple bands' that dominate large parts of Europa's surface are volcanic and not tectonic features (because their margins are diffuse and not sharp-edged as tectonic plate boundaries would be).

• Spacecraft must shrink yet another order of magnitude! The Discovery program with its NEAR and Pathfinder successes is just a first step, cutting the spacecraft weight and cost by a factor of up to ten and the development time by a factor three (compared to typical NASA s/c 10 years ago). But the goal must be spacecraft that weigh 10's of kg and cost 10's of millions of $ and are launched one year after program start.
• Earth science, classical planetary science and astrophysics dealing with planet detection out to distances of 100 light years must be integrated into one powerful program that also includes biologists. Goldin announced the upcoming foundation of a new institute to that effect that would operate in a kind of virtual way, having a big budget (100's of millions of $) but hardly any buerocracy.
• Current electronics and systems approaches must be replaced by thinking spacecraft, electronics that use DNA instead of FETs and work more complex than just with Boolean algebra. Robots must shrink to one inch. "We will darken the sky" with micro-spacecraft, Goldin told the stunned scientists, making the "last 50 years look like child's play."

Briefly noted:

SeaStar will fly on August 1st NASA announced today: this satellite from Orbital Sciences is carrying a NASA instrument which will deliver the first color images of the Earth on a global scale. (NASA News #161 of July 29, 1997)

Ice on the Moon remains unconfirmed: An attempt to reproduce the analysis of the Clementine radar experiments has not yielded any conclusive results so far - actually there is not even a confirmation of any radar power returned from the South polar region at all. The studies continue... (Progress report by R. Simpson at the conference, July 29, 1997)

Mathilde's low density remains a mystery

The expected density was about 2.5 g/cm**3, like the chondrite meteorites that the spectrum of Mathilde resembles closely (for experts: it's like a dehydrated C I or C M). The fact that the density is only half as big could in principle have three explanations:

• The asteroid is in fact a cloaked comet nucleus, i.e. it's a ball of ice that just happens to be coated by a crust that mimicks an ordinary meteorite. This scenario doesn't make sense, however, because this remarkable asteroid has many deep craters - and all the ejecta seen on the surface are as dark (albedo around 4%) as the rest. If the interior would be very different, we would see it.
• The asteroid is made out of a very different material than its exterior suggests - but why would the spectrum of Mathilde then resemble perfectly ordinary asteroids and meteorites so much?
• This leaves us with the widely accepted explanation that Mathilde has lots of holes: 40 to 50 % of the body is empty space. Mathilde thus seems to be a perfect example of a cosmic 'rubble pile', an agglomerate of loosely connected boulders. (Interestingly such a view of asteroids has already been published - in a Donald Duck cartoon some 40 years ago!)

Shouldn't the impacts have destroyed Mathilde alltogether - or rather have fused the boulders together? And shouldn't there be a satellite that could have slowed the rotation period (which 'normally' would be 5 to 15 hours) to the present value? NEAR undertook a dedicated search for such satellites when it receded from Mathilde but came up empty. And so the most successful asteroid flyby of all three (the optical navigation went perfect, despite all odds; more than 300 of the 534 images taken actually show Mathilde) has once more demonstrated how little we actually know about minor planets. (Talk and news conference at the conference by J. Veverka, July 28th, 1997)

Near Earth Asteroids - reshaped by planetary tides?

• The poor asteroid could be torn apart totally and then form a nice chain of mini-asteroids, strongly resembly comet Shoemaker-Levy 9 after its 1992 Jupiter encounter.
• Or the particles were torn apart and then came back together, forming an asteroid and a satellite - looking like Ida and Dactyl.
• Or a body just like Geographos formed after the particles reunited, extremely elongated and with the same strange 'bottle-like' form Geographos seems to have, according to the radar data, including little cusps at both ends. (Talk by B. Bottke at the conference, July 28, 1997)

Did the 'Vesta chips' weather? About 20 asteroids are known with orbital elements similar to the big asteroid Vesta that also have very similar spectra - in the visible light, that is. In the Near-IR, however, they are much redder than Vesta: This probably means that these 'Vesta chips' have suffered from 'space weathering.' Or aren't these bodies related to Vesta at all? Nowhere else, however, in the asteroid belt, are asteroids with optical spectra so similar to Vesta, which makes a common origin likely. (Talk at the conference by T. Burbine, July 28, 1997)

Arecibo radar measurements of Mathilde are planned this fall: As one of the first asteroids of this program after the upgrade of the Arecibo antenna Steve Ostro is planning to observe NEAR's first asteroid Mathilde this November. The radar images should allow to arrive at a much better value of the volume of the asteroid (with an error of only 9%) and thus a better density - if the (largely unknown) rotation state of Mathilde allows for a complete mapping (and the telescope is working all the time). If the observations run into trouble there are more opportunities in 2001 and 2014 - we just have to be patient... (Talk at the conference by S. Ostro, July 28, 1997)

Briefly noted:

The age of the surface of the Jupiter moon Europa stays controversial: The only way to guess it is to count impact craters, and the time history (and even the present rate) of impacts is far from clear. Nonetheless good arguments can be made that at least some areas of Europa (notably the 'ice raft' region) are only 1 to 100 million years old. This is a small fraction of the total age of Europa (4.6 billion years) - which means to a geologist that Europa is active today and that the likelyhood of an ocean still being there below the icy crust is high. (News conference at the conference by C. Chapman, July 28, 1997)

A new powerful online ephemeris calculation system has been created at the Jet Propulsion Laboratory: The Solar System Dynamics package will generate custom ephemerides, visibility calculations, physical data and more.

Go to the previous 10 issues. Other historical issues can be found in the Archive.