By Daniel Fischer
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Current mission news: MGS (latest pictures!) + Cassini + Stardust
The event in the early morning of May 31 will be tough - an annular eclipse practically at sunrise for Scotland, Iceland and Greenland: Espenak info, Williams info, Seal info, Klipsi info.
Rosetta faces unpleasant options: not one comet in sight that suits all wishesThe ambitious European comet mission Rosetta is in greater difficulties after the loss of the original launch window in January to comet 46P/Wirtanen (see Update # 247 lead) than it had seemed in the weeks since: Practically all of the potential targets have been eliminated for one reason or another. Only two possibilities remain at the moment: heading for 67P/Churyumov-Gerasimenko (nicknamed Chury) in February 2004 on an Ariane 5 P1+ or going to Wirtanen after all, in January 2004 on a Russian Proton DM. Both options carry severe technical risks, and with Chury also the survival, let alone scientific return, of the lander can not be guaranteed right now. Here are the pros and esp. cons as presented at the 12th meeting of Rosetta's Science Working Team at ESTEC in the Netherlands on Feb. 13:
First all-sky CMBR map from (W)MAP confirms current - weird - view of the UniverseJust a few years ago it would have been a stunning sensation, but when the analysis of the first year of observations with NASA's Microwave Anisotropy Probe (see Update # 225) was revealed - both in a press conference and in all technical detail on the web - on Feb. 11 it provided little more than a striking confirmation of what we had learned over the past 5 years: from balloon- and groundbased radiotelescopes scanning the Cosmic Microwave Background radiation (CMB) with ever greater detail (see e.g. Update # 223) as well as by scores of other means (starting in Update # 68). Still the results of MAP - renamed WMAP or Wilkinson Microwave Anisotropy Probe after a recently deceased leading CMB researcher - are a welcome addition to the mountain of results already in hand, as many of the key parameters that define our Universe are now known with much greater certainty.
Even using only the WMAP maps of the full sky, obtained in five wavelengths in order to remove all foreground sources, one can say e.g. that the baryon density is (0.024±0.001)/h², the overall matter density is (0.14±0.02)/h², the Hubble constant (divided by 100 km/s/Mpc) h is 0.72±0.05, the age of the Universe is 13.4±0.3 Gyr, and the Universe was 372'000±14'000 years old when radiation and matter decoupled. But if one combines the WMAP map with a few cosmological measurements obtained with other means, one can break various degeneracies and arrive at even more precise numbers. The WMAP researchers used data from two other CMB experiments that had higher angular resolution but observed only smaller fields (CBI and ACBAR), plus data of the large-scale structure of the Universe from the 2dFGRS galaxy survey and the Lyman-alpha forest caused by hydrogen clouds in intergalactic space and could thus conclude (amomg many other things), that
John Bahcall calls it "crazy and implausible", Bob Kirshner finds it "extravagant", and it is - with its dominance of Dark Energy and Dark Matter - certainly not what many had expected just half a decade ago. One of the WMAP papers, by Spergel et al., puts it into perspective: "Cosmology is now in a similar stage in its intellectual development to particle physics three decades ago when particle physicists converged on the current standard model. The standard model of particle physics fits a wide range of data, but does not answer many fundamental questions [...]. Similarly, the standard cosmological model has many deep open questions: What is the dark energy? What is the dark matter? What is the physical model behind inflation (or something like inflation)? Over the past three decades, precision tests have confirmed the standard model of particle physics and searched for distinctive signatures of the natural extension of the standard model: supersymmetry. Over the coming years, improving CMB, large scale structure, lensing, and supernova data will provide ever more rigorous tests of the cosmological standard model and search for new physics beyond the standard model."
Picture of Columbia's demise sharpens, but root cause still elusiveThe Columbia Accident Investigation Board on Feb. 13 released the first conclusions from a thermal analysis that indicates a breach of hot plasma into the orbiter's left wing as a key event. "Preliminary analysis by a NASA working group this week indicates that the temperature indications seen in Columbia's left wheel well during entry would require the presence of plasma (super heated gas surrounding the orbiter during re-entry)," the CAIB writes in its first official statement: "Heat transfer through the structure as from a missing tile would not be sufficient to cause the temperature indications seen in the last minutes of flight. Additional analysis is underway, looking at various scenarios in which a breach of some type, allowing plasma into the wheel well area or elsewhere in the wing, could occur." All possibilities are still on the table, from a hit by space debris to unexpected damage to the wing's leading edge (which many experts are considerin to be the most likely point for the breach) from the foam incident during launch. More recent insights:
Regarding the future of the ISS, meetings have taken place between NASA and Rosaviakosmos on overall resupply and crew exchange strategies, and between NASA and ESA on the potential rearrangement of taxi flights with ESA astronauts within this situation; these discussions have not yet reached conclusions and will be pursued. One option mentioned a lot: fly only two (one Russian, one American) on the next Soyuz in April/May, bring Expedition 6 home with the old Soyuz and wait for October. Meanwhile the crew that was meant to fly on the next Shuttle flight are still in training, and in parallel a crew for the next Soyuz flight are being trained in case they have to become the next Expedition crew. (With AW&ST of Feb. 17, 2003, p. 22-32)
Yet another hypothesis to explain the 'gullies on Mars'(see e.g. Updates # 194 and 232 story 2) has been presented by NASA researchers - in this view, based on images by the two current Mars orbiters, the gullies were created by trickling water from melting snow packs, not underground springs or pressurized flows, as had been suggested initially: JPL Release, Science@NASA [SN], ASU pictures [SR], APOD and coverage by S&T, Ast., BBC, New Sci., WP, UPI, AFP, Dsc., NYT, ST, SC, NZ, RP. The proposal is not new: SR. Earlier gully speculations: SC.
The south polar cap on the planet Mars consists primarily of water ice, and not carbon dioxide as previously believed - this view is based on an analysis of pits observed in the polar cap by the Mars Global Surveyor and Mars Odyssey spacecraft: a Caltech PR, more pictures and coverage by NSU, SC, BBC, Guardian, Ast., ST, Welt, NZ.
Models of possible water flow on Marshave been created based on new three-dimensional data from the Mars Global Surveyor spacecraft and a powerful state-of-the-art computer code: Ames Press Release. Early Mars warm enough to melt water? PSU Press Release. Mars without water? Astrobiol.Mag. How much water is there on Mars today? LANL Release [SD], Ast., Dsc., BBC, SC, NZ. Mars age questions: Univ. of Buffalo PR.
The first asteroid completely inside Earth's orbit(i.e. with an aphelion of less than 1 AU) has been discovered - 2003 CP20 was found near its maximum possible elongation from the sun of 76 deg, and the minimum possible distance from the earth is currently 0.19 AU (but passages within 0.05 AU of Venus are occurring): MPEC, the orbit, Ast., BBC, SC, NZ.
An impact/volcanism link after all? So far it's only a possible statistical association, while any mechanism remains elusive: Earthinst. PR. Shock waves through the Solar Nebula could explain water-rich meteorites: UA News. NEO researchers demand deeper survey, down to 200 meters: Workshop Report, NOAO Release, Nat'l Geogr.
A giant exoplanet orbiting a giant starwill not live long - the planet, just discovered in orbit about the giant star HD 47536 (23.5 solar diameters), already will perish within a few tens of millions of years: ESO Press Release, Ast., BBC, SC.
Another planet orbiting an even bigger star (26.3 solar diameters) has been announced at a conference in Germany: FSU Jena PM.
Planet formation on the fast track - a new concept has planets as massive as Jupiter form completely within just a few hundred years, rather than the millions mandated by today's most popular planet-formation model: Science News. Life on every third planet? NSU.
Magnetic storms on the Sun have weather cellsClusters of sunspots form their own weather patterns on the sun - large complexes of magnetic sunspots cause downdrafts in their vicinity that are fed by winds flowing into the sun from the surface and dissipated by strong winds flowing out from deep below the sunspots: Univ. of CO Press Release. Closing in on the physics behind CMEs: PPARC PR. Short-period soundwaves in the Sun: Göttingen PM. Früher: RP.
ESA chairs the International Living With a Star program, an unprecedented initiative in which space agencies worldwide are getting together to investigate how variations in the Sun affect the environment of Earth and the other planets, in the short and long term: ESA Science News. LWS missions assigned to APL: SD.
A report from the latest Totality Day at the Open University, covering mainly the Dec. 2002 solar eclipse, by the organizers.
The third-closest star (system)after the triple star Alpha Cen and Barnard's star has been discovered - SO025300.5+165258 has a very large proper motion of 5.06±0.03 arcsec/yr and a parallax of 0.43±0.13 arcsec: a paper by Teegarden & al., BBC, Welt. Young stars found near Earth, ideal to study planet formation: Swarthmore PR.
Coronal activity may be 'buried alive' in red giant stars - now astronomers have indirectly detected the presence of hot coronal gas in Aldebaran and Arcturus through UV emissions of highly charged carbon and oxygen detected by the FUSE satellite: Boulder PR.
A new end product of stellar evolution that looks like a brown dwarf has been found in the system EF Eridani: UCR News.
Star ejected from a triple system?Astronomers analyzing nearly 20 years of VLA data have discovered that a small star in a multiple-star system in the constellation Taurus probably has been ejected from the system after a close encounter with one of the system's more-massive components, presumed to be a compact double star: NRAO Press Release, NSU, ST, RP.
New class of star discovered, sub-dwarf B stars that pulsate like Jell-O, quivering in space through cycles that typically last an hour: UA News.
Stellar cocoons found in harsh environmentin the Carina nebula, including some oddballs with bulbous heads, irregular shapes and long, thin tails - each of these objects may harbor disks of gas and dust that could one day form planetary systems: NOAO, Boulder [SR] Press Releases, SC. The Orion proplyds, as observed with Keck: Keck Release, pictures, Ast.
Missing link found between old and young star clusters - about 100 star clusters have been discovered in the galaxy M 82 that are believed to be the ancestors of globular clusters: Univ. of Cambridge PR.
Huge eruption observed in Rho CasA huge eruption by a hypergiant star has blasted nearly 10,000 times the mass of the Earth into space: CfA Press Release, S&T, SC. This star might also be "best candidate for the next supernova": ING, NOSR Press Releases, Ast., NZ.
Supernovae did not play a role in Earth's mass extinctions as the explosion has to be closer than thought to cause environmental havoc: GSFC Release.
Short and long gamma-ray bursts different to the coreAn analysis of nearly 2,000 bursts has uncovered new discrepancies in the light patterns in bursts lasting less the two seconds and in bursts lasting longer than two seconds - one can now say with a high degree of statistical certainty that the two show a different physical behavior: PSU Press Release, Ast.
Another star tracked racing around the Galactic Center - S0-16 has passed within 60 AU of Sgr A*: UCLA PR, NSU. Feeding a galactic dragon: GSFC Press Release, SC, BBC. Black holes form first, galaxies follow: OSU Release.
Faint debris trail found in M 31The discovery of a faint trail of stars in the nearby Andromeda galaxy offers new evidence that large spiral galaxies have grown by gobbling up smaller satellite galaxies: UCSC Press Release.
A dwarf galaxy with most of its molecular gas in the outskirts and not near its center is IC 10: NRAO Press Release.
Pretty pictures from telescopes large and small
Adaptive Optics integrated into the secondary mirror of a telescope - crucial experiments were made in November 2002 and January 2003 at the 6.5-meter telescope at the MMT Observatory on Mount Hopkins, AZ: UA News [SR], Ast. AO also useful in opthalmology: Ast.
Staff returns to Mount Stromlo, eager to continue work and to rebuild the burned-down Australian observatory: Press Release.
South Pole telescope follows trail of neutrinos into deepest reaches of the UniverseIceCube, the extension of AMANDA, buried in Antarctic ice, promises unparalleled insight into such extraordinary astrophysical phenomena, calculations show: UCI and NorthEastern Press Releases, BBC. Earlier: NSU.
Compiled and written by Daniel Fischer