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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 |
will accompany the next Expedition on their Soyuz launch on Oct. 18 at 5:37 UTC, while the next shuttle will not launch before Sep. 12, 2004: ESA and NASA Releases on the Soyuz, a GAO Report on the impact of the grounding of the shuttle fleet, the charter and a summary of an Oct. 16 Hearing on manned spaceflight and coverage of Oct. 17: BBC 2, 1, AFP 2, 1, ARRL. Oct. 16: SN, FT 2, 1, SC. Oct. 15: FT, AFP, ST. Oct. 14: FT, AFP, ST. Oct. 13: BBC, AP. Oct. 10: FT. Oct. 9: SR, AP, SD, AFP, SC, ST. Oct. 8: FT, SC. Oct. 7: SR. Oct. 6: ST. Oct. 5: WP, ST. Oct. 4: WP, ST, RP. Oct. 3: SN, FT, SR, CNN, ABC, SC, ST 2, 1.
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First Chinese manned spaceflight total success - but what next?The launch was on time at 1:00 UTC on October 15 and so was the return of Shenzhou 5 with China's first yuhangyuan, Yang Liwei, 21½ hours later: 42½ years after the Soviet Union and the U.S., China has now demonstrated its ability to send its own into orbit, on a home-grown rocket and in a capsule that, though inspired by Russia's Soyuz, is also featuring many unique features. The question now is: for what purpose? Several reasons have been suggested by observers or are evident anyway. The flight of Shenzhou 5 should
But the big mystery remains: What role will yuhangyuans (as the space travellers are called in China; »taikonaut« is not used there) play in the space program as a whole? Big investments have been announced in recent months, both in space science (where a series of unmanned lunar missions is in the making as seems to be at least one optical space telescope) and in launcher development. For example a new familily of launchers should be ready by 2008 to carry 25 tons(!) into LEO and 14 tons into GTO. One major payload is said to be a mysterious (astronomical?) observing platform that would be put in LEO - might that be a destination for future yuhangyuans? Stay tuned ... |
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Is the topology of the Universe written on the wall?There may be another deep insight into the fundamental structure of the Universe hidden in the map of temperature fluctuations of the cosmic microwave background radiation delivered by the WMAP satellite (see Update # 249 story 2): is the Universe of infinite or finite extent? This question is related to but fundamentally independent of the fact whether space is curved or not. WMAP's results say that it is pretty flat, i.e. Euclidian in nature, but such a Universe could still be finite if the overall topology is more complex than Euclidian. Mathematically a wide variety of topologies are possible and a specific one is not predicted by cosmology's fundamental equations: One has to measure it, using astronomical data.And there is one piece of evidence indeed for a flat but finite Universe: The quadrupole component of the power spectrum of the CMB fluctuations is much smaller than expected in a Euclidian flat Universe. In other words: There are hardly any waves frozen into the CMB that are larger than 60° on the sky. This could have a variety of explanations, but the »simplest« one (for a mathematician, that is) would be to assume a non-Euclidian topology. And there is one that would explain the quadrupole deficit and would fit the measured flatness of space (Omega_total = 1.02±0.02, says WMAP): It is called Poincaré dodecahedral space. It would be a weird Universe where you could walk in one direction and eventually end up where you started. Here is how it works (and it has nothing to do with space »looking like a soccer ball« as some have written): A dodecahedron is a 3D structure made of 12 pentagons. A spherical dodecahedron is the same but »blown up« into a sphere: This increases the edge angle from about 117° to exactly 120° - and you can take 120 of these objects to tile the surface of a hypersphere - the three-dimensional surface (which represents what we experience as space) of a four- dimensional ball - without any gaps. We would thus experience a pretty much Euclidian space, but it would be »stitched together« in a weird fashion: This cannot be visualized, of course, but mathematically it works. And there is only one way to do it: Poincaré dodecahedral space has strictly defined properties which can - and must - be tested for in reality. One prediction is that Omega_total = 1.013: This is in agreement with the current error bars of the WMAP measurement, and in future it may be possible to get even sharper bounds on Omega_total. A second prediction results from the stitching-together effect: There should be temperature correlations in the CMB along matching circles in the sky! By sheer coincidence (?) the results on such a test were published one day before the dodecahedron model and its predictions appeared in Nature: The WMAP map was checked for all kinds of circles of different sizes - and those predicted by the model were just not there! As nice as it was (for a mathematician), it doesn't seem to work. Any Universe with a topology scale smaller than 24 Gigaparsec (78 billion light years) is ruled out by the lack of circles in the sky with similiar temperature patterns, but that does not prove that space is infinite: While many interesting topologies seem to fail the test, it is still possible that the Universe is flat and finite, but just not as small as in the dodecahedron model. WMAP's current extended mission or the Planck satellite promise some further insights. (Luminet & al., Nature 425 [Oct. 9, 2003] 593-5) |
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Galileo sent useful data til the very end!When the Galileo spacecraft was sunk into Jupiter on September 21 (see last Update story 3), it was broadcasting science data in real-time, but they could not be seen immediately - only weeks later it has become clear that the very final experiment was a smashing (no pun intended) success. To get the information out of the soon-to-be-fried data buffer, Galileo was programmed to increase the transmission rate from 20 to 32 bits per second: The signal was now so faint that it could be not recognized in real-time anymore and the displays at mission control all froze. This was expected, though, and Galileo's final broadcast was also recorded by broad-band receivers for later painstaking analysis.Days afterwards it emerged that the data could be extracted from these recordings indeed, and by early October is was clear that everything could be read: Galileo had delivered useful science til the very end, i.e. the moment it vanished behind Jupiter's limb, just minutes before burning up. Everything is there, from magnetic field and particle measurements to photometry in Amalthea's orbit (where strange flashes, perhaps from small moonlets, had been seen last November). Even the final seconds will be of use as the fading of the signal strength while Galileo slipped behind Jupiter contains information on the atmosphere's density. Future textbooks and space missions alike will profit from Galileo's final achievement. (AW&ST of Oct. 6, 2003 p. 44) |
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Laser AO in use at the KeckA major milestone in took place recently at the W.M. Keck Observatory when scientists, for the first time, used a laser to create an artificial guide star on the Keck II to correct the blurring of a star with adaptive optics: Keck Press Release.Largest gamma-ray observatory MAGIC opens on La Palma: Homepage, Pressemitt., Ast., NSU, NZ, Welt. SIRTF focused successfully - in addition to achieving final focus, the telescope has cooled to an operating temperature of approximately 5 Kelvin: JPL Release, ST. New minimum distance record for an asteroid!Tiny (and harmless) 2003 SQ222 approached Earth to within 80,000 km on September 27: Lowell Press Release, New Sci., S&T, Ast., BBC, SC, Closest Approach list.Spectacular bolide photo was none but apparently shows a Sun-illuminated contrail from a plane instead - although new images add additionals twists to the 'saga': the original APOD with an updated caption, helpful articles from CCNet (items 6-8; earlier with links to the new pictures, still earlier and even earlier), SC and CENAP and less helpful ones from BBC (earlier), ICWales (earlier, with a picture from a different perspective), Indep. Various meteor(ite) news of late: CCNet (item 11), WP, BBC, Plan. Soc. 'Lost' asteroid Hermes recoveredIt was the most famous one as it came pretty close to Earth in 1937 and is rather big: MPEC, NEO News [SR], S&T (earlier), CCNet (items 1-3; earlier, items 6-8), New Sci., BBC, AFP, RP.Did comets make life on Earth possible? Comets may have supplied at least part of the raw material for the origin of life on Earth: Nat'l Geogr. Chicxulub the big killer after all? CCNet (item 7). The first direct evidence of crystalline silicates in a proto-planetary disk surrounding a Sun-like star: NAOJ Press Release, BBC. 37 Gem best star for life? At least in the solar neighborhood: New Sci., AFP, BBC. Hunting for exoplanets' moons w/Eddington: ESA. Tons of Brown Dwarf spectra measured, show relationship to planets: Keck Release, BdW. "Black Drop" effect explainedTRACE observations of the 1999 transit of Mercury show that this phenomenon - often seen during transits of Venus in centuries past - is caused by the limb darkening of the Sun convolved with the PSF of the optics: a paper by Schneider & al. and an earlier poster. |
Four possible explanations for the loss of CONTOURhave now been pointed out - the probable proximate cause for this accident was structural failure of the spacecraft due to plume heating during the embedded solid-rocket motor burn: NASA Release [SR, SN], Ast., ST.Comet Encke returns on its 59th observed passage; the appearances date back to when it was first seen by French observer Pierre M�chain in 1786: S&T. Predictions for the Leonids of 2003do not give hope for more than 120 meteors per hour - but that's still more than usual: Vaubaillon page; also Jenniskens and Cooke, SC.U.S. gov't money for amateur astronomers? A bill makes progress: ST, Ast. Light pollution a topic in British parliament - the House of Commons science and technology committee have criticised the government for an "inconsistent approach" to the issue: BBC. Titan may have oily oceansThe giant Arecibo radio telescope in Puerto Rico has transmitted pulses of radio waves towards Titan, and analysis of the dim echoes suggests the presence of craters filled with oily oceans or lakes beneath the clouds: Cornell PR, Lorenz article, New Sci., BBC, SC, Welt.Small moons of Uranus, Neptune recovered, discovered - Uranus now has 27 known satellites: an IfA page [SR] and an updated list, Ast. (earlier). Confessions of an angry astrophysicistfor whom the ways this science is working today look terribly flawed can be found in a radical essay by López-Corredoira currently in Basel - while overblown in various respects ("cosmology is not a real science") it still seems to contain some uneasy thruths ...
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Compiled and written by Daniel Fischer
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