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By Daniel Fischer Every page present in Europe & the U.S.!
| Ahead | Awards 
The latest issue!
| A German companion! (SuW version) Current mission news: MGS (latest pictures!) + Cassini + Stardust |
the atmosphere over the Middle East on Jan. 31 without causing harm: a NASA Release, coverage by CNN, BBC, Discovery, AFP, Reuters, APOD, SPIEGEL, RP, NZ and previews by GSFC, SFGate, Astron., BBC, New Sci., AN, CNN, ST and SN. HESSI launch set for Feb. 5 - the High Energy Solar Spectroscopic Imager will study solar flares: GSFC, RAS and earlier Berkeley Releases and the Status. Yohkoh remains out of commission - over six weeks have passed since the solar eclipse mishap (see Update # 231 header), and very little progress has been made in recovering the Japanese X-ray satellite: SN.
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Major controversy over dusty consequences of impactsA scientific paper, coming along with an agressively worded press release, has caused big excitement among those planetary scientists who deal with impacts of asteroids (and comets) and their environmental consequences: The new study concludes that even the Chicxulub impact 65 Myr ago was not big enough to throw so much fine dust into the atmosphere that photosynthesis was shut down. If that result, which is based on extrapolations and not the actual detection of that dust in sediments, is true then there were other mechanisms at work which caused the famous K/TB mass extinction after that impact.This would be no big deal (several such mechanisms have been hypothesized over the years anyway) - but if even such a big impact of a 10-km asteroid or comet was a poor dust producer, smaller (and more frequent) ones would be even less dangerous. And the alternate mechanisms would probably not work at all for smaller impacts. The famous 'global catastrophy threshold', at which human civilization would collapse and billions would die might then be way above the 1-km limit often assumed in the current 'planetary defense' debate. The new study has already been attacked from several angles - it'll be interesting to see where the ongoing debate is leading and what political consequences on the current and planned near earth asteroid search programs it may have. |
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Our Milky Way as seen from way aboveIt's a picture no spacecraft will be able to take in a very long time: a bird's eye view of our own spiral galaxy. It's not a perfect view, in that it shows the central bar clearly but not the spiral arms, but it's based on direct astronomical observations and not some extrapolations from other galaxies. The picture, unveiled at a big astronomical conference in the U.S. in January, is based on the space positions of some 30,000 carbon stars that were identified among 500 million stars in the 2MASS infrared sky survey - because these stars share roughly the same absolute luminosity, their apparent IR brightness yielded a distance, making possible the final plot.A spiral galaxy rotating »the wrong way«has been identified thanks to dusty filaments that show clearly on which side of its disk we are looking: The spiral arms of NGC 4622 are not following, as all current models of spiral structure formation predict, but leading the rotation. "We were absolutely stunned by this result," says one of the discoverers, who already thinks he knows what happened: "We have suspected for a long time that NGC 4622 has suffered from some kind of interaction with another galaxy. Its two outer arms are lopsided, meaning something has disturbed it. The new HST images suggest, in fact, that NGC 4622 has consumed a small companion galaxy. In the center we see new evidence for a merger between NGC 4622 and a smaller galaxy. This could be the key to understanding the unusual leading arms." |
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Is our Solar System (with its Jupiter) typical after all?Most of the planetary systems of other stars discovered so far seem weird, with their (multi-)Jupiter-mass objects on either very close or on rather excentric orbits - there has not been one discovery of another »solar system« in which there is another Jupiter on a Jupiter-like orbit (i.e. circular at some 5 AU). This fact has raised more than one eyebrow among planetary theorists who had been able to demonstrate wonderfully - until 1995, that is - that our own Solar System is the typical outcome of the evolution of a circum-solar disk of dust. Were they all wrong, and is our solar system a rarity after all?
Not so fast, says a new analysis by two Australian astronomers
who make »the observational case for Jupiter being a typical
massive planet« - although currently all the radial-velocity
programs are not sensitive (or haven't observed long) enough to
detect an exo-Jupiter on a 12-year-orbit. But there have been so
many exoplanet discoveries by now that trends are emerging in a
diagram plotting minimum mass vs. orbital period: As one moves
closer to the current detection limit, there is a growing
overabundance of exoplanets with low masses and long orbital
periods. Extrapolating from that trend one can dare to state that
exoplanets with a mass of one Jupiter are three times as common
as those with two Jupiter masses.
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Brown Dwarf companion imaged just 14 AU next to a starIt's not the first Brown Dwarf discovered in close proximity of another star, but it sets a record in a different way: Never before has a BD companion been imaged directly just 14 Astronomical Units from its star. In this case it's 15 Sagittae, and the existence of a brown dwarf there at 55 to 78 times the mass of planet Jupiter raises puzzling questions about its formation. It is probably too massive to have formed the way we believe that planets do, namely from a circumstellar disk of gas and dust when the star was young. The finding suggests that a diversity of processes act to populate the outer regions of other solar systems. The parent star is very similar to our Sun, yet its brown dwarf companion has a mass dozens of times the combined mass of all the planets in our solar system.»Plejades phenomenon« fakes protoplanetary systemsNot all dust one finds around a young star actually belongs to it and will eventually turn into a disk from which planets can be born: It can happen that a star is just moving through a pre-existing cloud of old dust which then reflects its light. This is the case with the famous Plejades star cluster where the faint reflection nebula is due to such »borrowed« dust - and such a »Plejades phenomenon« has now turned out to be rather common in the Milky Way. Hoping to image for the first time extrasolar analogs to the Kuiper Belt U.S. astronomers found that the dust surrounding five stars out of 100 surveyed is actually a cloud of interstellar dust on a collision course with each star. The research team cautions that, in some cases, a star could have a circumstellar debris disk and interact with interstellar dust simultaneously: High-resolution observations are needed to see the origin of far-infrared emission from these stars, to distinguish between disks and other dusty structures. |
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Licht echoes imaged around a 3rd supernovaFirst it was seen in 1988 around the famous Supernova 1987A, then around SN 1991T - and now a third case of a small ring of light around a supernova has been found some two years after the explosion on SW 1998bu. An echo results when light emitted near supernova maximum is redirected toward the earth by dust scattering and delayed by ther increased path length, and there are actually two echos in an HST image, an outer ring with radius of 0.24"�0.01" and a inner component with a full width at half maximum of 0.14"�0.01". Using a Cepheid distance to M96 of 10.5 Mpc, the dust producing the outer ring is placed at an average distance of 120�15 parsec from the supernova and this may correspond to the distance between the supernova and the disk of M96. The inner echo comes from dust which is no more than 10 parsec from the explosion and which may have surrounded the progenitor.Nearby supernova involved in an eco-disaster 2 Myr ago?So far it's just an intriguing speculation, but there are three lines of evidence that could be linked - and constitute the first known case in which a moderately distant supernova explosion has caused a significant ecological effect on Earth, including the extinction of a number of marine species.
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Cosmic background radiations and the history of star formationover the complete history of the Universe are making headlines one again (see also Update # 200) - while one study uses deep sky surveys from no fewer than five different space observatories (and 3 radio telescopes) to put most of the action into the z~0.8 realm, another one based on 2MASS has most of the star formation between z=1 and 7 - and a third one, extrapolating from the Hubble Deep Field, sees the main starburst even farther back.
The »color of the Universe«: a pale turqoise greenThis funny »study« is also a spin-off of systematic attempts to understand the star formation history of the Universe: More than 200,000 galaxy spectra collected during the 2dF Galaxy Redshift Survey so far have been added up carefully (after correcting for the redshifts) - and then the color was calculated by which such a mix of all galaxies would appear to the human eye. "The color is quite close to the standard shade of pale turqoise, although it's a few percent greener," says Karl Glazebrook, an assistant professor of astronomy in the Krieger School of Arts and Sciences at Hopkins. For computer buffs, the RGB values are 0.269, 0.388, 0.342. It's the large numbers of old red stars and young blue stars in the universe that add up to green today, but it was not always the case: The universe probably started with a "blue period" early in its history dominated by young blue stars, has moved into the current "green period," and will eventually enter a final "red period" where decreased star formation allows older, redder stars to dominate the Universe. |
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The hunt for gravitational waves is onFor the first time in history several big laser interferometers built for the hunt for gravitational waves from deep space have been operating in parallel from Dec. 28, 2001, until Jan. 14: In the U.S. states of Washington and Louisiana and in Germany, the LIGO interferometers and the smaller but still powerful GEO 600 were working most of the time during that interval. And while no signal was detected during this largely engineering-oriented run (and none was expected by experts anyway), this was a major milestone in the hunt for gravitational waves.»Hint of supersymmetry« just a math error ...A widely reported claim of a possible violation of the standard model of particle physics (Update # 218 story 3) has been withdrawn for the time being: While the experiment was o.k., the theoretical predictions that it had been found to be in conflict with have since turned out to be flawed! Deeply hidden math errors in several independent (!) papers all conspired to work into the same direction. Compared to the corrected value the experimental result is not in significant disagreement anymore, but the measurements continue and a new, even better value will be announced this year. And this time there is much more confidence that the theorists have done their homework, too ... |
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ISS UpdateRussia's contribution to the ISS is under review, according to this document, while NASA has released a list of requirements for ISS visitors and the work on an amateur telescope for the ISS is making progress. Coverage of Feb. 2: HT, SC, New Sci. Feb. 1: OS, NYT, CNN, HC, StarTrek.com, BBC. |
Jan. 31:
SR,
SC,
FT,
ST.
Jan. 30:
Nashville
Business Journal,
AFP,
SC.
Jan. 28:
SN,
AFP.
Jan. 26:
HC,
CNN,
AFP
(other story),
ST,
BBC.
Jan. 25:
Reuters,
FT.
Jan. 24:
FT.
Jan. 22:
AFP.
HST SM-3B Update: Columbia has finally been rolled to the launch pad after delays - a long mission preview, the status and coverage of Jan. 31: FT. Jan. 29: FT, ST. Jan. 28: FT. Jan. 24: FT. |
Stardust changes course, aims for cometNASA's comet-bound spacecraft Stardust has successfully completed a critical deep space maneuver, positioning itself on a course to encounter comet Wild 2 in January 2004 and collect dust from the comet - at 21:56 UTC on January 18, Stardust fired its thrusters for nearly 111 seconds, increasing the speed of the spacecraft by 2.65 m/s: JPL Release, CNN.Mars Odyssey has reached its final orbit on Jan. 30, after small orbit trim maneuvers complemented the larger maneuvers executed two weeks earlier and tweaked the orbit to just the right altitude and ground track coverage: Mission Status, SPIEGEL. A new Mars atlas, based on MGS images: MSSS Atlas. CONTOUR shipped to GSFC, with the launch of the multi-comet mission set for July 1: JHU Press Release, WP. Star occultation by Titan observed with AOOn Dec. 20, 2001, Saturn's moon Titan occulted both stars of a binary system - the spatially resolved observation of the occultation with an Adaptive Optics system provides a new, powerful technique for investigating Titan's atmosphere from Earth: details & pictures, the Palomar AO page and an Astronomy story (that is not an "exclusive", BTW - the CM had it already on Jan. 26 ...).NASA ballon down after record flightA NASA scientific balloon has set a new flight record of almost 32 days after completing two orbits around the South Pole - the record-breaking balloon carried the Trans-Iron Galactic Element Recorder (Tiger) experiment, designed to search for the origin of cosmic rays, atomic particles that travel through the galaxy at near light-speeds and shower the Earth constantly: NASA Release [SN, SR], Homepage, Astronomy, CNN, APOD, SPIEGEL, NZ.Hi-res SRTM products releasedDisplaying spectacular new 3-D images and animations of California from space, JPL scientists on Jan. 22 announced the release of high-resolution topographic data of the continental United States gathered during the February 2000 Shuttle Radar Topography Mission: JPL Release, PIA 033... 28, 29, 30, 31, 32, 33, 34 and NYT.The first pictures from the PROBA satellite launched last October have been released - it's a demonstrator satellite, set to lead the way for future small missions: ESA Release. SPOT 5 nearly finished: BBC. Teledesic down to 30 satellite constellation - initially almost 1000 satellites were planned: Press Release, ST. |
Another LINEAR erupts - C/2000 WM1 has jumped from 6m to 3mwithin a day in late January and is holding the naked eye brightness ever since (but the comet is currently visible only in the Southern hemisphere): Charts & light curves, pictures of January and Feb. 1 and Astronomy and NZ stories.New comet could reach 4th mag. in March! C/2002 C1 (Ikeya-Zhang) is now in Cetus with 9th mag.: an early ephemeris and charts.
2nd Faulkes telescope goes to Siding SpringTwo 2-meter telescopes dedicated solely to education will be built in Hawaii and Australia by a British philantrope: Homepage of the Faulkes Telescope Project, a Press Release on the Australian scope and Aussie media coverage.Last White Oval on Jupiter colliding with the GRF - pictures of Jan. 26 and Feb. 2 and an SC story. Galactic bars destroy themselvesby driving interstellar gas towards the galactic center, where the mass buildup ultimately disrupts the orbits of the bar stars: BIMA Press Release.Radio mapping of molecular clouds in nearby spiral galaxy M 33 reveals an important role of magnetic fields in early star formation: Berkeley Press Release. Turbulence and thick gas as a possible precursor to galactic evolutionIn a huge river of primordial hydrogen flowing from the neighboring Magellanic Clouds into our own Milky Way galaxy, astronomers have discovered the first evidence of turbulence and concluded that the invisible, hot mass of gas surrounding our galaxy is much thicker than physicists previously thought: Cornell Press Release.
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All other historical issues can be found in the Archive.
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Compiled and written by Daniel Fischer
(send me a mail to [email protected]!), Skyweek
