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By Daniel Fischer Every page present in Europe & the U.S.!
| Ahead | Awards 
The latest issue!
| A German companion - only available here! Current mission news: MGS (latest pictures!) + Cassini + Stardust |
have been released on April 30, temporarily slowing down the web server of the STScI (there are now enough mirror sites to satisfy the demand, though): STScI, NASA, ESA HST and IfA Hawaii Press Releases and coverage by HC, BBC, CNN, S&T, Ast., New Sci. (earlier), NYT, WP, HT, OS, SC, FT (other story), ST, Sp (fr�her), RP, NZ (fr�her). |
Old and faint White Dwarfs confirm an age of the Universe of 13 to 14 GyrIt took even the Hubble Space Telescope a combined 8 days of exposure time, but the effort was worth it: The oldest and faintest White Dwarfs in the globular cluster Messier 4 have now been detected, at 30th magnitude. And because the way White Dwarfs cool and fade over time is pretty well known, the stars could be dated: They are 12.7±0.7 billion years old. And since they are the oldest stars in the Galaxy and one knows from other studies (about the formation of large-scale structure in the Universe) that it formed about one billion years after the Big Bang, the age of the Universe comes out to 13 to 14 billion years.This result fits well with the outcome of completely different calculations (that rest on various data sets on the large-scale structure of the Universe, irregularities in the Microwave Background Radiation and the current expansion velocity; see e.g. Update # 223) which yield 12 to 14 billion years: It is reassuring that modern cosmology seems to have come to grips with the fundamental numbers of the Universe, without contradictions. What it all means, is a different matter, though ... |
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Ultra-high Energy Cosmic Rays traced back to dormant Supermassive Black Holes?The statistics are poor, but the hint is tempting: 4 (out of some 40) Cosmic Ray particles with extremely high energies (UHECRs) seem to have come from four different galaxies in the constellation Ursa Major that are believed to harbor old Supermassive Black Holes with many millions of solar masses that were once powering quasar activity. This phase is long gone there now, but if (big if!) those SBHs are spinning, they would drag magnetic field lines with them and could act as tremendous particle accelerators. So far there is only one (other) galaxy known where X-ray spectral evidence indicates a spinning SBH.UHECRs are extremely rare: One hits a square kilometer on Earth only once per decade. Nonetheless large detectors have seen a few dozen of them in recent years, but until now the sources were a complete mystery: They had to be outside the Milky Way (there are no objects known here that could produce them), but within a few million light years (otherwise interactions with the Cosmic Microwave Background Radiation would have reduced their energy). One possible reason none of the other UHECRs could be traced back to a former quasar: The magnetic field in the Galaxy could have twisted their trajectories, an effect that is small in the direction to UMa. |
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The strongest link yet between a Gamma Ray Burst and a supernovais contained in X-ray spectra of the afterglow of GRB 011211 from the satellite XMM-Newton: They show »emission lines of magnesium, silicon, sulphur, argon, calcium and possibly nickel, arising in metal-enriched material with an outflow velocity of the order of one-tenth the speed of light. These observations strongly favor models where a supernova explosion from a massive star progenitor precedes the burst event and is responsible for the outflowing matter.« One such model would be the so-called supranova in which a massive star first collapses to a neutron star as in a regular supernova - but a few (in this case: about 4) days later the neutron star further collapses into a black hole. During that 2nd collapse the GRB is generated in a tightly beamed fashion - and in the case of GRB 011211 that beam of gamma rays was directed nearly towards us and so excited the supernova ejecta travelling towards us at hight speed. (Reeves & al., Nature 416 [April 4, 2002] 512-5) |
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ISS UpdateAtlantis is back, and the next Soyuz has reached the ISS - with a Russian, an Italian and a South African. A MPG PM on the Plasmakristall-Experiment, ESA Press Releases on Mandela calling and the liftoff, minutes of an Expedition 3 debriefing, a hi-res picture of the ISS with the new truss and coverage of May 2: ST, AFP. May 1: CNN, HC. April 30: AFP, ST, BBC. April 29: SN, BBC, AFP, Rtr, RP, NZ. April 28: NYT, AFP. |
April 27:
SN,
CNN,
SC,
ST,
Sp.
April 26:
WELT.
April 25:
Pictures,
ISS Status,
ESA News,
ST
(earlier),
BBC, SN,
Dsc,
SC,
AFP,
AP,
Ananova,
Sp,
RP, NZ.
April 24:
SN,
BBC.
April 23:
ABC, AFP,
Sp,
NZ.
April 22:
Sp.
April 20:
ST,
BBC.
April 19:
AW&ST, AFP,
AN, ST.
Shuttle successor may share little in common with its predecessor, a team of government and aerospace industry experts working under the SLI has said - 15 concepts will be studied further: MSFC Release [SN], SR, AN, HC, AFP, SC, ST, WELT. |
Rare line-up of all planets visible to the naked eyenow underway (see also last Update story 1 sidebar) : Science@NASA, ESA Science News, S&T, pictures of May 3 & April 29 and coverage by Ast., SC (earlier), Post-Gaz., RP.Ikeya-Zhang now fading, down to 4.5 mag. in early May: IZ + ISS, IZ + an aurora, S&T, SC. Aurorae on April 19/20 over Danmark: pictures by Lohf & Thannh�user. Big flare on April 21: SOHO pics. NASA, university scientists see prediction of solar storms in future: MSFC Press Release. Klipsi, the eclipse chaser, portrayed by SwissInfo. Lots of cold dust in the Virgo Clusterhas been found by German astronomers - it converts up to 50% of the visible radiation from the galaxies into infrared light: MPG PRI, RP.A small black hole whirling space around it seems to have been found by XMM-Newton during an outburst from the vicinity of a black-hole candidate called XTE J1650-500: ESA Science News. More SNO data confirm solar neutrino oscillationsThe number of electron-neutrinos is about 1/3 of the number expected, but the total number of all three types of neutrino agrees well with calculations, as had already been announced last June (see Update # 225 story 2): a paper by the SNO Collab., SNO and PPARC Press Releases, PNU, S&T, NYT, BBC, ST.Succession of relationships keeps heavenly bodies youngClusters where stars gather more densely than usual are veritable hotbeds of partner-swapping. Some stars engage in half a dozen or so relationships during their lifetime: NSU, NZ.Odd rotation behavior in stars - some adolescent stars rebel against the norm by spinning more slowly than their peers: JPL Release. Subaru finds huge gas cloud expanding around galaxyObservations with Suprime-Cam on Subaru Telescope have detected for the first time long filaments of ionized hydrogen gas extending 110,000 light years above the disk of the active galaxy NGC 4388: Press Release.Chandra views the Tarantula Nebula in the LMC - massive stars are producing intense radiation and searing winds of multimillion-degree gas that carve out gigantic super-bubbles in the surrounding gas: Chandra Release, MSFC Photo. Chandra observes titanic merger - the X-ray Observatory has provided the best X-ray image yet of two Milky Way-like galaxies in the midst of a head-on collision: Chandra Press Release, Sp, RP, NZ. Every 6th Near Earth Asteroid has a moonThis has been revealed by a recent series of radar discoveries (5 cases in total) - apparently these fast-rotating bodies were partially torn apart when they came too close to a terrestrial planet: JPL, Caltech and Cornell Press Releases (more) and coverage by BBC, PhysicsWeb, SC, RP.And double bodies in the Kuiper Belt aren't rare either, though there the formation mechanism is much more mysterious: STScI Press Release, NSU, SC, Sp, NZ. The first predictions for the Leonids of 2002 are out - Lyytinen & al. see two more storms, but not necessarily bigger than those of 2001: URSA Page. More trouble for astronomy on Mauna KeaA Hawaiian government body has sued NASA, charging that the construction of new telescopes atop the islands' tallest peak could threaten areas deemed sacred by many residents: LAT."Cultural Astronomy" - the role of astronomy in problems of general cultural interest: a looong website from Singapore. |
Lots of transiting small dark bodieshave been found during the OGLE program, but none of them have been proven to be planets yet: a paper by Udalski & al. and coverage by S&T and NZ.More evidence for planets in the disk of Beta Pic has been found in Keck observations of the innermost zones: Keck Press Release, Astron., CNN. Stable 'Earth' planets in 47 UMa's Habitable Zone after all?That's what a new British simulation indicates which may be thus show the possibility of billions of 'Earths' in the galaxy: RAS Press Release, BBC, BdW.Ground-based European Nulling Interferometer Experiment to hunt for exoplanets with the VLTI from 2006: ESA Science News. More money for Pluto (and Europa)?A loose bipartisan consensus is falling into place in the U.S. House of Representatives to add some $60m to NASA's FY 2003 budget earmarked specifically for NASA's on/off/on again Pluto-Kuiper Belt mission: SD, SR, Mikulski statement. What the mission is all about: SciAm (long!).Space Technology 7 to help LISA, the gravitational wave satellite constellation: AW&ST. Stardust sets new distance recordOn April 18th, the comet-bound mission reached its furthest distance from the Sun, also known as its aphelion - the spacecraft was 2.72 AU (407 mio. km) from the Sun and near the middle of the asteroid belt, the farthest distance ever reached by a solar-powered spacecraft: Status.CONTOUR is now at Cape Canaveral for its July 1 launch as all testing of the multi-comet spacecraft has been completed: JHU and NASA Press Releases. Mars Viking leader diesThe former NASA manager of the Viking missions to Mars, James S. Martin, Jr., has died April 14 after a long battle with cancer at 81: NASA News Release. Mars Odyssey has new project manager: JPL Release.A second mission extension for the MGS began in April 2002 and will continue the mission into late 2004: JPL Spotlight. New MGS pictures of gullies: MSSS. More studies of Martian hazards necessary, a reports by the National Research Council has said - a number of aspects of the Martian environment could pose risks to future astronauts, ranging from rough terrain to hazardous chemicals to native biological organisms: PR, New Sci., ST. Aqua launch now planned for May 4The primary role of the new NASA Earth observer, as the name implies, is to gather information about water in the Earth's system - equipped with six state-of-the-art instruments, Aqua will collect data on global precipitation, evaporation and the cycling of water: Homepage, summary, HC, NYT, New Sci., BBC. Earlier: JPL Release. Still earlier: AW&ST.Starshine 2 has reenteredEarth's atmosphere on April 26, ending the mission after just over four months - estimates say the fiery plunge back to Earth occurred within a few minutes of 11:00 UTC, most likely near the British Isles: News Page, SN. Earlier: Science@NASA.
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Compiled and written by Daniel Fischer
(send me a mail to [email protected]!), Skyweek
