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By Daniel Fischer Every page present in Europe & the U.S.!
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The latest issue!
| A German companion! (SuW version) Current mission news: MGS (latest pictures!) + Cassini + Galileo + NEAR |
Here is a Space.com page with a preview and updates. Get the brightness data from JPL and ICQ - and all the other info (incl. pictures!) from Bernhards Kometenprojekt!
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Case for close-by LMC, high Ho strengthensA certain class of binary stars promises to be an outstanding 'standard candle' which could provide the distance to the Large Magellanic Cloud - the basic step of the cosmological distance ladder - to a precision of a few percent. Two such detached, non-interacting, main sequence B-type eclipsing binary systems have now been investigated in detail in the LMC - and both of them, HV2274 and now HV982, yield identical distances of just 46 kiloparsec or 150 000 light years. And this is significantly closer than the 50 kpc or 163 000 light years that are usually adopted as the LMC distance. This, in turn, makes the Hubble constant some 8 % larger, favoring a value of at least 76 km/s/Mpc.The new technique combines the classical analysis of eclipsing binary light and radial velocity curves with analysis of the UV/optical energy distribution of the system. The former yields precise and theory-independent data for the stellar masses and radii, while the latter yields stellar temperatures and metallicity, reddening information and a distance 'attenuation factor'. Combining these results then provides a virtually complete description of the properties of the binary components and a precise distance determination - where no free parameters can be 'tuned'. Furthermore there are so many of these systems known in the LMC that not even the mean distance of this minor galaxy but also its 3D structure will one day be mapped. So far, only two binary distances have been determined, both leading to 45.8+/-1.5 kpc for the distance of LMC's center. The Ho Key Project, however (see Update # 132), had used 50 kpc, so their result of 71 (see the paper by Mould & al.) most likely has to be increased to at least 76 km/s/Mpc. Such a correction of the cosmological distance ladder would also remove the striking discrepancy between the distance determinations for NGC 4258 (see Update # 148 story 4). Adding in that possible other correction (see Update # 189 story 4) would push Ho in the realm of 90... (Press Release by Fitzpatrick & al. from the 196th AAS Meeting) |
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Radio astronomers secure much of high-frequency spectrumAstronomers using the millimeter-wave region of the radio spectrum have won crucial protection for their science: Dedicated allocations for radio astronomy have been given final approval by the 2,500 delegates to the World Radiocommunication Conference (WRC-00), which on June 2 concluded a month of deliberations in Istanbul, Turkey. Radio services can transmit in these parts of the spectrum as long as they don't hinder astronomers' attempts to catch faint signals from the cosmos. WRC-00 has protected for science all the frequencies between 71 and 275 Gigahertz (GHz) that radio astronomers currently use, adding more than 90 GHz of spectrum to the 44 GHz already set aside in this frequency range.As a result, radio astronomy is now allocated most of the frequencies between 71 and 275 GHz that can get through the Earth's atmosphere - all three atmospheric "windows", apart from their very edges. The new spectrum allocations for radio astronomy are the first since 1979. Millimeter-wave astronomy was then in its infancy and many of its needs were not yet known. As astronomers began to explore this region of the spectrum they found spectral lines from many interesting molecules in space. Many of those lines had not fallen into the areas originally set aside for astronomy, but most will be under the new allocations. |
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Search for planets in globular cluster comes up emptyIt had been a bold idea: monitoring the light of the thousands of stars in a globular cluster with the Hubble Space Telescope over an extended period, in the hope of catching several planets passing in front of their suns by a small dimming effect (see Update # 159 story 2 sidebar 2). Now the results are in: not one planet has turned up although some 17 dimming events would have been expected if planets were as frequent in globular clusters as they are in the vicinity of the Sun.Apparently planets in globular clusters are much rarer, if they exist at all. The high density of stars in globular clusters might suppress the formation of planets in the first place, it could be a lack of heavy elements that prevents their formation, or planets form but are often kicked out of their systems. The most bizarre idea: The tidal forces from neighboring stars just pull giant planets apart and destroy them. In any case the lack of planets in 47 Tucanae is "startling and unsettling" to leading planetary theorist Alan Boss. |
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Sugar in space: glycolaldehyde found near Galactic CenterThe prospects for life in the Universe just got sweeter, with the first discovery of a simple sugar molecule in space. The discovery of the sugar molecule glycolaldehyde in a giant cloud of gas and dust near the center of our own Milky Way Galaxy was made by scientists using the National Science Foundation's 12 Meter Telescope, a radio telescope on Kitt Peak, Arizona, that is threatened by immediate closure. The discovery means it is increasingly likely that the chemical precursors to life are formed in such clouds long before planets develop around the stars.Glycolaldehyde, an 8-atom molecule composed of carbon, oxygen and hydrogen, can combine with other molecules to form the more-complex sugars Ribose and Glucose. Ribose is a building block of nucleic acids such as RNA and DNA, which carry the genetic code of living organisms. Glucose is the sugar found in fruits. Glycolaldehyde contains exactly the same atoms, though in a different molecular structure, as methyl formate and acetic acid, both of which were detected previously in interstellar clouds. Glycolaldehyde is a simpler molecular cousin to table sugar. |
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NPOI resolves Polaris: an unusual Cepheid starThe Navy Prototype Optical Interferometer (NPOI), an array of telescopes near Flagstaff, AZ, currently possessing the resolving capability of a single 38-meter optical telescope, has revealed that Polaris is 46 times larger than our own Sun: This unprecedented direct radius measurement is precise enough to reveal important clues to the star's internal structure. Long known to be a "Cepheid" variable star, the new measurement confirms that Polaris is a Cepheid of a very unusual nature. Cepheids get brighter and dimmer because they constantly change size. A complex series of events deep in the atmosphere of these stars causes the outer layers of the stellar atmosphere to alternately expand and contract.Usually all the material in the outer atmosphere moves in the same direction at the same time. The NPOI observations of Polaris directly confirm an earlier discovery that Polaris is an "overtone pulsator": When Polaris pulsates, not all of its atmosphere moves in the same direction at the same time. The NPOI observations for Polaris show that the North Star has a radius of 46 +/- 3 solar radii. With an observed period of four days, theories say that if Polaris is a fundamental mode pulsator, like most Cepheids, it should only have a radius of 38 solar radii. The period-radius relation for overtone pulsators, however, predicts larger radii for Cepheids at all periods: When compared with this other period-radius relation the observed large radius for Polaris is in perfect agreement. |
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Mir crew back on Earth - and the next one will include a tourist!The next crew to visit the Mir space station will include a paying passenger - Dennis Tito, 59, a former scientist at NASA's Jet Propulsion Laboratory. The announcement was made on June 16, just as two Russian cosmonauts returned to Earth after spending the past few months reactivating Mir. Tito will be paying about $20 million for the one-week mission - details will be announced on June 19: MirCorp Press Releases.Coverage of the mission's end & new plans: Press Release, Spaceflight Now (earlier), Space.com, AP, RP, BBC, SPIEGEL, SpaceViews, SZ, AFP, CNN. Earlier coverage: AFP (earlier, still earlier), Space.com ( earlier), Moscow Times (long!), SpaceViews, CNN, Spaceflight Now, RP. Economic success unlikely? Fla. Today. SSTV images from Mir captured by radio hams: MAREX. ESA books 9 launches to the ISSon Ariane 5 rockets that will carry Automated Transfer Vehicles (ATVs) - it's Arianespace's biggest deal ever with a government institution: Spacefl. Now, SpaceViews, Space Daily. 'Tasty' space food a must for longer missions: Fla. Today. Robots to lend a hand during ISS EVAs: JSC Press Release, Space.com, CNN.An internal battle between Russia's space agency and its military could jeopardize the launch of Zvezda: Space.com. Zvezda's features: RP. Controllers are testing the docking systems aboard ISS for its arrival: Status. The system has failed: AvNow. Pizza Hut Zvezda rocket advertisement controversy continues: Space.com. More launch preparations: Space Daily, Fla. Today, Status. Proton passed key test for Zvezda flight with another launch: SpaceViews, Fla. Today. NEAR's Near-Infrared Sensor turned offOne of NEAR Shoemaker's six scientific instruments has been turned off after the NEAR mission team detected a power surge in the device - during routine operations on May 13, the Near-Infrared Spectrometer (NIS) inexplicably began drawing excessive current from the spacecraft's power supply and stopped sending data; after it wouldn't work on June 5, the NEAR team opted to keep the instrument off unless a solution comes up: News Flash, SpaceViews, CNN, Space.com, Fla. Today, SpaceRef.New pictures: two pits, around the bend, near the Ridge's end, inside the large crater, ideal lighting, twilight's last gleaming. And the weekly reports from June 9 and 16. NGST delayed to 2009 - it's too hardThe successor to the Hubble Space Telescope won't fly until the end of the decade, two years later than originally planned, because of the technical challenges involved - but the project will fly a prototype of the telescope that could conceivably be more powerful than Hubble itself: SpaceViews.A possible spin-off from Hubble technology could be a carbon coating developed for the experimental cryocooler that will be attached onto Hubble's NICMOS during the next servicing mission in 2001: GSFC Press Release (Spacefl. Now version). NASA's ACTS technology mission comes to an endAfter 81 months of operations and far exceeding its planned 24-month mission, NASA's Advanced Communications Technology Satellite (ACTS) has concluded its extensive experiments program: Glenn Center News Release.Pegasus carries Air Force experiments to orbit - a compact package of exotic space experiments was launched into Earth orbit on June 7: Homepages of TSX-5 at Orbital and USAF, previews by Spaceflight Now and Fla. Today, the status, an Orbital Press Release and reports by Space.com, SpaceViews, Fla. Today. No test flight for X-33 in sight - troubles abound for experimental vehicle: Fla. Today. The X-Prize contest goes on, with more than a dozen entrants competing for a $10 million payout after a spacecraft makes two round trips to the edge of space with three persons aboard: CNN. Galileo making longest looping orbit around JupiterGalileo continues to cruise through space on the longest and largest orbit around Jupiter since its arrival in December 1995 - the spacecraft's current orbit is 222 days long and will reach apojove at a distance of 290 Jupiter radii (20.7 million km) on Sept. 8: GLL This Week.The dust cloud around Ganymede is maintained by impacts from interplanetary dust particles, a detailled analysis has shown - dust measurements in the vicinities of satellites by spacecraft detectors are suggested as a beneficial tool to obtain more knowledge about the satellite surfaces, as well as dusty planetary rings maintained by satellites through the impact ejecta mechanism: Krüger & al. |
RHIC turned onNo space-shattering disaster - as some had feared - struck when the Relativistic Heavy Ion Collider (RHIC), the "HST of nuclear physics", started smashing atoms in mid-June: Homepage, Brookhaven, AIP, Weizmann Press Releases, NYT, Discovery, BBC, RP stories. The RHIC was safe, detailled studies had shown: Jaffe & al on "Speculative 'Disaster Scenarios' at RHIC."Major solar flares / no well-observable aurorae / China suffersA series of major flares, one of it of the rare white-light variety and the best-observed ever, occured on the Sun in early June and sent Coronal Mass Ejections towards Earth - but the detailled conditions on impact did not lead to widely visible aurorae: SpaceWeather.com, the current solar forecast and AstroAlert page, the aurora oval shape, an experimental predictions, the solar wind and Wetterleuchten.The early warnings for June 8 via NASA Science News, GSFC Press Release, Space.com, Discovery, SpaceRef (with many links), SunSpot, AP, SPIEGEL, SpaceViews, CNN. Little happened in the skies the following nights: CNN, BBC, RP, Space.com. But China's telecommunications were apparently affected: Space Daily, Space.com. Tracking geomagnetic storms with 4 radio telescopes through the intensity fluctuations or "scintillation" they produce in distant radio sources: U of CA Press Release. ESA approves funding to extend Ulysses missionThe European Space Agency has agreed to fund the Ulysses mission for an extra 2 years 9 months - until 30 September 2004: ESA Science News, SpaceViews, Space.com. First Cluster pair fueled: ESA Science News.ACRIMSAT's pointing fully restored after months of work: Space.com. How the IMAGE mission became reality, as told by the satellite's PI: NASA Science News. More meteorites from the Moon and Marscollected recently in Oman have brought the tally of martian meteorites to 16 and the number of lunar examples to 17 - all told, roughly 20,000 meteorites from all extraterrestrial sources have been found on Earth: Space.com.The observability of impacts on the Moon from the Earth is discussed in a WGN paper by Imponente & Sigismondi. Meteor lights up Colorado night - "Anyone who was out camping that weekend was blown away by the sight": Space.com. RadioShack to sponsor lunar roverLunaCorp has announced on June 15 that it has signed up electronics retailer RadioShack as the first corporate sponsor of its planned lunar rover mission - RadioShack is the first of what LunaCorp hopes to be several commercial sponsors for its Icebreaker Moon Rover, a mission planned for launch in late 2003 to survey the polar regions of the Moon in search for water ice: Homepage, Press Release (Spacefl. Now, Fla. Today versions), AvNow, Discovery, Space.com, SpaceRef, SpaceViews, CNN. Ice on Moon remains elusive: Space.com.Lunar Transient Phenomena still debated after some of the best evidence is seen: BBC, SZ. Superb lunar mosaic images: Heusner. Big solstice Moon: SpaceScience. How the energy from the lunar tides gets dissipated on Earth has finally been observed directly with the TOPEX/Poseidon satellite and its radar altimeter for ocean heights: NASA Science News. Americans would rather go to the Moon than abroadAccording to a new poll, 32 percent of all Americans would be willing to vacation on the Moon while only 20 percent would go to a foreign country; 37 percent opted for a beautiful beach, though: CNBC News Release.Astronaut photos from space still valuable for monitoring changes on Earth - some 400,000 images are on file: JSC Press Release.
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Compiled and written by Daniel Fischer
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