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Update # 166 of January 13th, 2000, at 17:00 UTC
Fat MACHOs bend starlight - 'naked' Black Holes adrift in the Galaxy?A dark, extremely compact body with 6 solar masses: What else other than a lonely Black Hole could that be? Two such mystery objects have been discovered by the Massive Compact Halo Object (MACHO) collaboration by the microlensing effect they had on background stars, and the mass determinations seem conclusive, thanks to coordinated ground-based and Hubble photometry. No known celestial object with such a high mass is known that would not also emit enough light to have been seen during the observations of the two microlensing events. If the objects are isolated black holes, they could be the remnants of exploded massive stars. One alternative interpretation of the data has already come to the attention of the Cosmic Mirror, though: The massive MACHOs could be isolated neutron stars (with masses around 1.4 suns) - surrounded by massive disks. |
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Number of NEAs down by a factor of 2NASA scientists taking a census of large asteroids in our solar system neighborhood have cut their estimate in half - the revised calculation comes from data gathered by NASA's Near-Earth Asteroid Tracking System (NEAT). Until now the population of large, near-Earth asteroids was thought to be between 1000 and 2000, but now it seems that there are only between 500 and 1000 NEAs larger than 1 km in diameter - about half the old number. (Rabinowitz & al., Nature of Jan. 13, p. 165-6)The new figures may represent good news in the quest to achieve NASA's stated goal of finding 90% of all large NEAs by 2010. Right now 322 are known: That was a fairly small fraction of 2000 asteroids, but 322 represents a large chunk of the newly calculated total. The 90% catalog completeness could be reached within 20 years, despite the limited funding of the NEO search programs. (The famous 'impact' movies of 1998, in contrast, have grossed over 900 million dollars by now, according to the IMDB: Armageddon is at #11 with 554 and Deep Impact at #50 with 349 mill.$...) |
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Zvezda launch slips to August, another Shuttle-poor year loomsBecause the engines of the Proton that was to launch the ISS' most important module are so rotten that they have to be replaced, Russia had to admit on Jan. 11 that the Zvezda won't fly until August the earliest! During the investigation of last October's failed Proton launch it had been found that the rocket's engines were suffering from basically the same flaws that had brought down another Proton in July: contamination due to dirty conditions in the Voronezh Mechanical Plant where the engines were built in the 1992/3 period."An examination of the parts of the failed LV Ser. No. 38602 revealed metallic or non-metallic debris in internal chambers of Stage II such as a piece of asbestos fabric under the 8D411K-13 valve head, traces of aluminum and copper, and sand," the investigation report says: "the engines installed on Stages II and III of the Proton LVs that failed during the July 5 or October 27 missions and the engines that failed in the November 5, 1992 lot-by-lot tests were all manufactured in the 1992/93 period. The latter period is characterized by a slump in the production of liquid rocket engines at the Voronezh Mechanical Plant (down to 19% of the 1986 level in 1992) combined with the launch of civil-oriented production by the Engine Department in 1992. From that point in time on, the per-produced-item number of non-compliances has jumped up." The new large delay of the Zvezda launch makes it more likely that NASA will fly a shuttle mission to the embryonic ISS before the module arrives: The task of the astronauts would be the first major repairs (!) of the station as two out of six batteries of the Zarya module have already failed. The same orbiter and the same astronauts (or most of them) would then fly again after the Zvezda has finally arrived, in order to prepare the station for its first permanent crew. A decision on this double mission is expected by the end of the month. Still, like in 1999 there will be only 2 or 3 missions in 2000... |
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Galileo continues mission despite unclear financesFinds best evidence ever for ocean under Europa's ice today during a Jan. 3rd, 2000, flybyAlthough NASA still hasn't decided what to do with the Galileo Jupiter orbiter now that even the extended mission (that ran all through 1998 and 1999) is over, and related JPL announcements contradict each other, the controllers let the mission continue for the time being. Hopes are for a "Galileo Millennium Mission" carrying on with several moon flybys through 2000. Already on January 3rd, Galileo performed another close flyby of Europa (closest approach: 351 km), in an encounter planned especially around magnetometric measurements. This time everything went without a glitch, and the crucial data were in hand and analyzed already on January 10th.The results seem to be clear-cut and to provide "powerful new evidence that a liquid ocean lies beneath Europa's icy crust": Galileo's magnetometer observed directional changes consistent with the type that would occur if Europa contained a shell of electrically conducting material, such as a salty, liquid ocean, somewhere in the outer 100 kilometers. Jupiter's magnetic field at Europa's position changes direction every 5 1/2 hours, and such a changing field can drive electrical currents in a conductor, such as an ocean. Those currents produce a field similar to Earth's magnetic field, but with its magnetic north pole near Europa's equator and constantly moving. In fact, it is actually reversing direction entirely every 5-1/2 hours. Galileo's new data showed that the pole's position had moved (measurements during earlier flybys hadn't been conclusive), thus providing key evidence for the existence of an ocean. It is not likely that the electric currents on Europa flow through solid surface ice, but melted ice containing salts is a fairly good conductor, as would be partially melted ice or slush. While there is ample evidence on the icy surface of Europa that the interior of the moon was liquid at some point in the past, the magnetometric data are the first that all but prove the existence of an ocean under the ice today - a remarkable discovery for a spacecraft that should long have retired by now...
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How watching The Plejades makes for better potatoes...The origin of a seemingly bizarre 'astronomical' rule used for centuries by farmers in the Andes to decide when to plant new potatoes has now been found: The number of stars the naked eye sees in the Plejades star cluster (which can be 11 in dark places) depends on the absence or presence of wispy cirrus clouds that are otherwise hard to detect in the night sky - and these clouds are Nature's early warning system for El Niño conditions which in turn affect the quantity of rainfall many months in the future. The farmers' traditional rule says that the rainfall during the growing season of October to May can be predicted from the brightness of stars in the Pleiades asterism in June: The brighter the stars, they say, the more abundant the rains. (Orlove & al., Nature Jan. 6, 2000, p. 68-71) |
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Leonids'99: the complete picture!A very detailled article on the Leonid meteor storm of 1999 (see Updates # 158 and 160) has now been prepared by the IMO - based on 277172 meteors: Bulletin 15 of the International Leonid Watch.The HST is resuming its scientific workTwo sets of Early Release Observations have been scheduled for this week, but one will need approximately two weeks to process the data and transform it into pictures ready for release: GSFC Press Release, SpaceViews story.A Hubble Heritage image of a starburst in NGC 4214: STScI Press Release, Space.com and CNN stories. Meanwhile the commissioning of the XMM has resumed and all instruments are now on: ESA Science News, Space.com, Space Daily. And the successes of Chandra so far are reviewed in the NYT. Commercial future for Mir found?A Western venture capital company will apparently provide funding to support sending a crew to the Russian space station as early as March - but details are as sketchy as ever: SpaceViews. More insights in Mir's future: Space Daily, Fla. Today, Space.com, BBC, SpaceViews again. |
Space VLBI yields sharpest quasar images yetLed by Japan's ISAS, the VLBI Space Observatory Program enables about 40 Earth-based radio telescopes from more than 15 countries to co-observe with the Japanese space VLBI satellite HALCA - new images will be revealed next week: JPL Press Release, Space.com story.Terra healthy, checkout continuesAfter more than 3 weeks of the spacecraft being on-orbit, NASA controllers report Terra Mission operations are going extremely well, with no significant problems at this time: Space Daily. How the computer trouble was fixed: SpaceViews, Space.com.ACRIMSAT had problems, too, with its gyros: Space.com. Another safe mode for SOHO - Emergency Sun Reacquisition entered: SpaceRef.
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Compiled and written by Daniel Fischer
