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By Daniel Fischer Every page in Europe & the U.S.!
| Ahead | Awards The latest issue! 
| An experimental German companion. Current mission news: MGS (latest pictures!) + Cassini + Galileo + NEAR |
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SRTM launch now set for Feb. 11th, 17:30-19:40 UTC: KSC status report. Nomad wrapup - 5 of 7 stones tagged by robot were meteorites: Sp. D., Wired.
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Extremely distant galaxies in the Hubble Deep FieldObservations of the famous Hubble Deep Fields North and South with the space telescope's WFPC2 and NICMOS IR cameras as well as ground-based telescopes have led to the identification of over 4000 extremely distant galaxies (see Update # 118 - last story - for earlier work by the same group). While spectra of these faint galaxies cannot be taken with current large telescopes, it is possible to guess their redshifts from photometry in just a few color bands quite reliably: Nearly 1000 galaxies in the HDF have redshifts greater than 2, more than 50 have redshifts greater than 5 - and the redshifts of several galaxies even exceed 10!While this is remarkable by itself, it could also revolutionize our understanding of the star formation history of the Universe. Previous analysis of ythe HDF had suggested that star formation reached its peak relatively recently, at roughly half the current age of the Universe. But the new data show no such peak: The activity continues to increase as one looks back farther and farther in time. The early Universe was much more active than believed, with star formation proceeding at more than 100 times the present rate - a challenge for theorists. (SUNY Press Release of Jan. 12th) |
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What slows down stars? 'Magnetic disk-locking' questionedHow do young stars get rid of the enormous spin they must acquire when the condense out of their birth cloud? Leading star-formation theories currently use a mechanism called magnetic disk-locking, in which still-forming stars can become magnetically "locked" under certain circumstances to the slowly swirling disks of gas and dust that are frequently found to encircle young stars. The young star's field acts as a sort of leash, tying the star to its disk and braking it down. But an infrared search for such disks around young stars in active stellar nurseries has turned up many without disks - and on the other hand fast rotating young stars were common. This means that another braking mechanism must be invoked: Perhaps stellar winds carry the angular momentum away at one point? (Press Release of Jan. 12th) |
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"Superbubble" led to formation of a ring of molecular cloudsA new analysis of a survey of molecular clouds has now led to the conclusion that the creation of several star forming clouds in our galaxy was triggered by a battery of massive supernova explosions 40 - 50 million years ago: Most of the star forming clouds within a few thousand light years of our sun are expanding away from a central location. This point in space also coincides with a large, 50 million-year-old star cluster in the constellation Perseus - and a series of supernova explosions there seems to have created a "superbubble" of superheated gas in interstellar space that pushed ambient thin gas into a "supershell" of denser, cool gas - which eventually fragmented into dark clouds of star forming gas (i.e. molecular clouds) on the perimeter of the bubbleIn early stages superbubbles grow rapidly as gas heated by supernovas expands quickly into the galaxy. Our galaxy is a collection of gas, stars and dust, flattened into a thin disk like a CD. The gas in the disk of the galaxy gets thinner as away from the center plane, similar to how the Earth's atmosphere becomes thinner at higher altitudes. As the nearly spherical bubble grows, it expands more quickly where the gas is thinner and balloons out, like the mushroom cloud from a nuclear explosion on Earth. In the middle of the disk the expansion slows considerably as much of the high pressure hot gas expands into the 'cap' of the mushroom. The middle is also where gas is dense enough to provide enough material to the supershell for new cloud formation. The intersection of a supershell and the galactic disk has been dubbed a "super-ring" by scientists and is where the gas is densest - and exactly such a ring was now found in the molecular cloud survey: It has been named the Gould's Belt Super-ring (or GBS), and our Sun is located inside it but close to the edge. Although one can accurately measure the velocity at which the Gould's Belt Super-ring is expanding, one cannot accurately measure the distance of its gas from Earth. Further study is necessary to confirm the new findings, and future missions such as NASA's Space Interferometry Mission (SIM) will be essential to support the suspicion that this ring of gas is indeed part of a supershell. |
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The next big X-ray satellite: Japan's Astro-EIt's the 3rd major X-ray astronomy mission to launch within several months: After NASA's Chandra last July and ESA's XMM (still no decent name...) last December it's now Japan's turn. On February 8th at 1:30 UTC an M-5 rocket will launch the Astro-E satellite (which should get a colorful name after reaching orbit): It will showcase an entirely new technology in X-ray detection that not only will serve as a test bed for future missions but also will earn the distinction of being the coldest known object in space.It is the X-ray Spectrometer (XRS), developed jointly by NASA's GSFC and Japan's ISAS which measures the heat created by individual X-ray photons, as opposed to converting X-rays to electrical charges and then collecting that charge, which is the mechanism in other X-ray detectors. Using this new technique, it is possible to measure the energies of individual X-rays with a precision some 10 times greater than with previous X-ray sensors. To sense the heat of a single photon, however, the XRS detector must be cooled to an extremely low temperature, only 0.06 degrees Kelvin - what makes the XRS detector the coldest object in space. Astro-E is primarily a spectroscopy mission: Along with the XRS are four X-ray Imaging Spectrometer (XIS) instruments (for 0.4 - 10 keV) and the Hard X-Ray Detector (HXD, for 10 - 700 keV). The imaging instrument utilizes detectors similar to those flown on ASCA, Astro-E's precursor, yet with twice the collection efficiency at certain X-ray wavelengths. The HXD will extend Astro-E's observation ability into the "hard" or higher-energy X-ray wavelengths with the highest sensitivity ever achieved. Astro-E will attain a near-Earth circular orbit of approximately 550 km. Its payload weighs 1650 kg and measures 6.5 x 5.4 x 2.1 m. |
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Triple test of space technologies in Soyuz rocket launchOn February 9th at 5:20 UTC a Soyuz rocket will take off from Baikonur with an unusual payload: The new Fregat upper stage will be tested with a dummy payload and two novel reentry systems will be tried out that could "revolutionize the transportation of good between orbital stations and the Earth."
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NEAR's first rendezvous burn a success!Preliminary indications show the NEAR spacecraft is on a steady path to Eros, after a braking maneuver on Feb. 3rd adjusted its approach speed and trajectory toward the large asteroid. At 17:00 UTC, NEAR's medium-sized thrusters fired for 90 seconds and eased the spacecraft from 69 km/h (relative to Eros) to 29 km/h. The maneuver also moves NEAR's trajectory about 100 km closer to its target. The operation was a slightly modified version of the rendezvous burn scheduled for Feb. 2nd, which was canceled after NEAR went into "safe" hold.Mission operators at the Applied Physics Laboratory sent new commands to NEAR late on the 2nd, dividing the original maneuver into two parts. A second burn on Feb. 8 will bump NEAR's approach speed to 35 km/h and put it back on its original track to the asteroid. All critical science operations - including a low-phase flyby on Feb. 13 - remain on schedule. The flyby will put NEAR directly between the sun and Eros, affording a unique opportunity to map the asteroid's minerals under optimal lighting. The safe mode had been caused by incorrect data input to the spacecraft attitude control system as onboard accelerometers were powered up, which resulted in a small autonomous engine firing. Fuel expenditure was insignificant. However, some science observations were lost that were scheduled to take place during the time that the spacecraft was in safe hold. After another major effort on the part of the sequencing and operations teams, a new set of commands has been loaded on the spacecraft to recover the most critical of these observations, which include image sequences of Eros and an infrared spectrometer mirror geometry test. |
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JAWSAT and its satellites: Some good and some bad newsOne week after the maiden launch of the Minotaur rocket with its scores of small satellites (see Update # 170 story 3), some of them are in good shape, others are not:
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200 years ago: Herschel discovers the IR!February 11th marks the 200th anniversary of the day when the famous astronomer Sir William Herschel discovered infrared rays, while he was studying sunlight. Today, infrared radiation from celestial objects provides some of the most important information about the universe available to astronomers. In 1800 Herschel published the results of a series of experiments he had carried out "on the heating powers of coloured rays." Herschel spread sunlight out into a spectrum and placed thermometers into the light of different colours. He noticed that red light gave him the greatest temperature rise, but was most surprised to find that a thermometer placed off the red end of the spectrum where no light was visible recorded an even higher temperature.Herschel deduced that the thermometer was registering invisible radiant heat, what he called "calorific rays". He went on to prove that this radiant heat - what we now call infrared radiation - obeyed the same laws of reflection and refraction as visible light. Infrared astronomy has come a long way in the 200 years since those early observations of the Sun by Herschel. Most infrared radiation from space cannot be measured from Earth's surface because the atmosphere absorbs so much. Astronomers overcome this problem by building telescopes on high mountains in very dry places, by flying balloon experiments, and most recently by using satellites, such as ESA's Infrared Space Observatory. (RAS Press Release # 2 of Feb. 4, 2000) |
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Amateur photograph of big 'lunar impact' questionableGerman newspapers and astronomers alike have been confused this week by a strange photograph taken by a Berlin amateur on Jan. 18: Did he capture a gigantic impact plume on the Moon - or rather optical reflections inside his telescope? To most astrophotographers the latter explanation is clear. The original negative is now being scrutinized by planetary scientists while a 2nd independent picture as well as a visual sighting of a lunar transient during that night have been reported. |
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Mars still an attractive targetOver the next five years, four space agencies want to send spacecraft to Mars, with many others hitching rides - their representatives converged in London last week for the first meeting of the International Mars Exploration Working Group (IMEWG) since the loss of NASA's MCO and MPL: IMEWG Homepage, ESA Science News, SpaceViews story.The search for MPL signals continues - again the data analysis will take a few days: JPL Release, CNN, Space.com, AP stories. It's a complex operation: Stanford story. Quiet please at Jodrell Bank: BBC. Sand avalanches on Mars seen in recent MGS pictures: MSSS Release, CNN, Space.com stories. Cassini uses its High Gain Antenna nowLast week the Saturn-bound spacecraft executed a smooth transition to the HGA - prior to this, Cassini was nominally oriented with the HGA toward the Sun for thermal control purposes. The increased performance of the HGA will enable the high data rates required for instrument checkout and Jupiter activities later this year - this will be the nominal configuration for the remainder of the mission: SigEvents.The 5th in-flight checkout of the Titan probe Huygens was successfully completed during the night of 2 to 3 February - while the Cassini/Huygens spacecraft continues flying through the asteroid belt, on its way to Jupiter: ESA Science News. Tons of proposals for future ESA spacecrafthave been received for the flexi missions F2 & F3 (to be launched in 2007 to 2009) - a list of fancy names and acronyms (but without explanations) is provided by ESA Science News. For ESA's long-term strategy see Update # 153 story 5 sidebar.SMART-1 spacecraft and payload take shape for Moon journeyThe phase C-D activities that started last November require that the precise design of the spacecraft (see Update # 153 story 5) be finalised by the end of this February and that a Structural and Thermal Model of the spacecraft be available by the second half of the year. The payload development is already proceeding at full speed: ESA Science News. |
Goldin threat: Launch Zvezda by summer or we use our own ICM!The head of the U.S. space agency hopes the Russians will launch their service module to the ISS this year, but if they fail again, he says, the U.S. will put up its own in December - the Interim Control Module (ICM). The decision will be made in July: NYT, Fla. Today, Aviation Now, BBC, SpaceViews.Russia promises to fly Zvezda by June in response to Goldin: Space.com. What the ISS will eventually look like is getting more unclear: Fla. Today. How the ISS will be used commercially - a master plan: Space.com. Shuttle schedule hinges on Zvezda launch: Fla. Today. Mir's orbit to be boosted 40 to 60 kilometers higher by the newly arrived Progress ship: AFP. How Mir will come back to life: Space.com. Movie shooting still possible on-board Mir - if money is found: Space.com. Solar smoke ringsThe Sun put on a dynamic show this week with a series of swirling coronal mass ejections, beginning on January 28, 2000: SpaceScience, Space.com.The first daylight image of an aurora - clever use of a red filter made it possible from Kiruna: EZ = Space.com. Light and shadow in the Carina NebulaHubble spots unseen details of a mysterious, complex structure within NGC 3372: STScI Press Release; CNN, Discovery, BBC stories.
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All other historical issues can be found in the Archive.
The U.S. site of this Cosmic Mirror has been visited
since it was issued (the German site has no counter).
Compiled and written by Daniel Fischer
(send me a mail to [email protected]!), Skyweek
