Cosmologist Stephen Hawking plans to retire next year. The 66-year-old author of the popular science bestseller A Brief History of Time became famous for his theories about gravity, black holes, the big bang, and the nature of time.

Hawking, the Lucasian Professor of Mathematics at Cambridge University (a position once held by Isaac Newton), plans to step down at the end of the academic year, in accordance with a University policy of retirement at the end of the academic year in which officeholders turn 67, the Associated Press reports.

Another 66-year-old scientist at Cambridge, Peter Lawrence, argues against mandatory retirement ages for scientists in the May issue of the science journal Nature, saying that many well-known scientists have done excellent work after traditional retirement age. "Mandatory retirement policies condone and institutionalize discrimination," he writes.

But Hawking, who is paralyzed by motor neuron disease, intends to continue his exploration of time and space at Cambridge in a smaller role. He believes that space exploration may be the key to the survival of the human race.

Hawking told CNN earlier this month that if humans can survive the next 200 years and learn to live in space, then our future will be bright. "I believe that the long-term future of the human race must be in space," he said. "It will be difficult enough to avoid disaster on planet Earth in the next 100 years, let alone next thousand, or million. The human race shouldn't have all its eggs in one basket, or on one planet. Let's hope we can avoid dropping the basket until we have spread the load." Read more!

Oct. 28, 2008: Stop! Take your finger off that doorbell. Something spooky is happening behind your back. Turn around, tip back your mask, and behold the sunset.

It's a Halloween sky show.

On Oct. 31st, the crescent Moon will sneak up on Venus for a close encounter of startling beauty. The gathering is best seen just after sunset when the twilight is pumpkin-orange and Halloween doorbells are chiming in earnest. Venus hovers just above the southwestern horizon, the brightest light in the sky, while the exquisitely slender Moon approaches just a few degrees below: sky map.

Above: Venus and the crescent Moon photographed in July 2007 by Dan Bush of Albany, Missouri. The scene will be much the same on Halloween 2008. [Larger image]

Okay, stop staring. There's candy to be gathered.

One night later, you can give the sequel your undivided attention. On Nov. 1st, Venus and the Moon emerge from the twilight side-by-side, Venus on the right, the Moon on the left: sky map. Look carefully at the Moon. Can you see a ghostly image of the full Moon inside the bright horns of the crescent? That’s called "Earthshine" or sometimes "the da Vinci glow" because Leonardo da Vinci was the first person to explain it: Sunlight hits Earth and ricochets to the Moon, casting a sheen of light across the dark lunar terrain. A crescent Moon with Earthshine is one of the loveliest sights in the heavens.

The show continues on Nov. 2nd with Venus, the still-slender crescent Moon, and Jupiter arrayed in a broad line across the southwestern sky: sky map. This linear arrangement attracts attention almost as much as the luminosity of its points: Venus, the Moon and Jupiter are the brightest objects in the heavens, visible from light-polluted cities even before the twilight sky fades to black.

Trace your finger upward along the line—that is where the Moon is going. Nightfall on Nov. 3rd reveals the Moon transported to Jupiter: sky map. The two form a pair so tight and eye-catching, it may take your breath away.

As hard as it may be to believe, these nights of dark beauty are just a hint of things to come. The real show begins one month after Halloween when Venus, the Moon, and Jupiter converge on a tiny patch of sky no bigger than the end of your thumb held at arm's length: sky map. Dec. 1st is the best night to look, even better than Halloween.

Now that's scary. Read more!

Chandrayaan-1 spacecraft has entered deep space after crossing the 150,000 km (one and a half lakh km) distance mark from the Earth. This happened after the successful completion of the spacecraft’s third orbit raising manoeuvre today (October 26, 2008) morning.

During this manoeuvre which was initiated at 07:08 IST, the spacecraft’s 440 Newton liquid engine was fired for about nine and a half minutes. With this, Chandrayaan-1 entered a much higher elliptical orbit around the Earth. The apogee (farthest point to Earth) of this orbit lies at 164,600 km while the perigee (nearest point to Earth) is at 348 km. In this orbit, Chandrayaan-1 takes about 73 hours to go round the Earth once.

The antennas of the Indian Deep Space Network at Byalalu are playing a crucial role in tracking and communicating with Chandrayaan-1 spacecraft in such a high orbit. The spacecraft performance is normal. More orbit raising manoeuvres are planned in the coming few days to take Chandrayaan-1 towards the Moon.

Read more!

by Sean Walker

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Asteroid 2008 UZ drifted across the field during an evening imaging run. Click on the image to see an animation of the object's movement.

Paul Mortfield

Despite the growing number of professional surveys searching for near-Earth asteroids, amateurs still can bag a few new discoveries.

Amateur Paul Mortfield spends time with every imaging run he completes blinking each exposure and comparing the results to older survey images to see if something new appeared.

The effort has paid off. Mortfield has been credited with the discovery of two new asteroids, officially designated 2008 UY and 2008 UZ. Both objects are roughly 20th magnitude, and barely noticeable above the background signal in his exposures.

"Using a 16-inch telescope at f/8.9, I managed to capture these faint objects slowly drifting across my CCD images while taking 15-minute exposures," Mortfield explains. "They were only noticeable when I stretched each frame and blinked the results. I suppose if this stuff was easy, everyone would be doing it!"

Mortfield details a few simple steps that any imager can perform to search for asteroids, variable stars, and supernovae, as well as other scientifically useful information, hidden in the images we capture every clear night. Read about his experiences in Sky & Telescope's December issue, on newsstands now.

Read more!

Associated Press/AP Online By MARCIA DUNN

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CAPE CANAVERAL, Fla. - NASA's efforts to get the ailing Hubble Space Telescope working again have hit a snag, and engineers are trying to figure out their next step.

Officials had hoped to have the 18-year-old observatory back in business Friday, after it stopped sending pictures three weeks ago. But a pair of problems cropped up Thursday, and now recovery operations are on hold.

It's unclear how long the telescope will be prevented from transmitting its stunning photos of the cosmos.

The soonest it could be operating fully again is late next week, said Art Whipple, a Hubble manager. At worst, the observatory might remain inactive until astronauts arrive with a replacement part next year.

"We're still optimistic," he told reporters Friday.

Flight controllers at Goddard Space Flight Center in Greenbelt, Md., began the lengthy process of restoring data transmission on Wednesday. Everything was going well, until late Thursday afternoon.

First, a low-voltage power supply problem prevented one of Hubble's cameras from being rebooted properly, and then computer trouble struck and all efforts ceased.

It's too soon to know whether the two problems are related, said Whipple.

"We're in the early stage of going through a mountain of data that has been downloaded over the last 24 hours," he said at a news conference.

Hubble's command and data-handling system for science instruments failed late last month and prevented the telescope from capturing and beaming down data used to create the pictures for which Hubble is known.

Because of the breakdown, NASA delayed its final Hubble repair mission by shuttle astronauts that was set for October. The mission won't happen until at least February, possibly later.

The latest setback is not expected to further delay the shuttle mission, Whipple said.

The recovery efforts involved switching to a backup channel for the command and data-handling system that had been dormant since the telescope was launched in 1990. That part, at least, seemed to go well, Whipple said.

So far, this isn't the longest that Hubble has been inactive since NASA's 1993 mission to correct its blurred vision. In 1999, science operations were halted about six weeks because of gyroscope failures that were remedied by astronauts whose flight quickly followed the breakdown.

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On the Net:

NASA: http://www.nasa.gov/mission-pages/hubble/main/index.html

A service of YellowBrix, Inc. Read more!

NEW DELHI, India (CNN) -- India launched its first lunar mission on Wednesday, with hopes of achieving high-resolution images of the moon's topography and diving into the international space race.

For India the $80 million mission puts the country on the inside track of a fast-developing Asian space race.

The unmanned lunar orbiter Chandrayaan-1, or "moon craft" in ancient Sanskrit, came at 6:20 a.m. Wednesday (8:50 p.m. ET) from the Sriharikota space center in southern India.

The two-year mission seeks high-resolution imaging of the moon's surface, especially the permanently shadowed polar regions, according to the Indian Space Research Organization. It will also search for evidence of water or ice and attempt to identify the chemical breakdown of certain lunar rocks, the group said.

Despite the numerous missions to the moon over the past 50 years, "we really don't have a good map of the moon," said Miles O'Brien, CNN chief technology and environment correspondent. "The goal is to come up with a very intricate, three-dimensional map of the moon."

The Chandrayaan-1 is carrying payloads from the United States, the European Union and Bulgaria, and India plans to share the data from the mission with other programs, including NASA. Watch the launch of India's first lunar mission »

SRO said on its Web site that the mission would lay the groundwork for future lunar missions and "probe the physical characteristics of the lunar surface in greater depth than previous missions by other nations."

"It will also give us a deeper understanding about the planet Earth itself or its origins," a statement on the Web site said. "Earlier missions did not come out with a full understanding of the moon and that is the reason scientists are still interested. This will lay the foundation for bigger missions and also open up new possibilities of international networking and support for planetary programs."

Until now, India's space launches have been more practical, with weather warning satellites and communiations systems, The Associated Press cited former NASA associated administrator Scott Pace as saying.

To date, only the U.S. Russia, the European Space Agency, Japan and China have sent missions to the moon, according to AP.

Critics of the mission have questioned its $80 million price tag, saying the money should have been spent by the government to improve education and fight poverty.

But, "there are scientists that would argue that there are plenty of things we don't know about the moon ... and India might have the know-how" to find answers, said CNN's Sara Sidner in New Delhi.

The United States and the Soviet Union dominated the field of lunar exploration from the late 1950s. The United States is preparing for its own mission slated for next spring -- the first U.S. lunar mission in more than a decade, according to NASA.

Soviet spacecraft were the first to fly by, land on and orbit the moon. Luna 1, launched on January 2, 1959, and sped by the moon two days later.

Luna 2 was launched on an impact mission on September 12, 1959, striking the surface two days later. Luna 9 launched on January 31, 1966, becoming the first craft to successfully land on the moon and send back data, touching down on the surface on January 31, 1966, and transmitting until February 3, 1967, when its batteries ran out.

Luna 10 was launched March 31, 1966, entered lunar orbit on April 3, and operated for 56 days.

But the United States' Apollo missions were the first manned missions to reach the moon, culminating with six missions that set down on the surface. The first, Apollo 11, left earth on July 16, 1969, and landed astronauts Neil Armstrong and Edwin Aldrin on the lunar surface on July 20 while command module pilot Michael Collins orbited above. The astronauts returned safely to earth on July 24.
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Most recently India's fellow Asian nations, China and Japan, put lunar orbiters in place. Japan launched the Kaguya orbiter in October 2007, followed by China's launch of the Chang'e mission a few weeks later. Video Watch what is shaping up to be a new space race »

"Each nation is doing its own thing to drive its research technology for the well-being of that nation," AP quoted Charles Vick, a space analyst for the Washington think tank GlobalSecurity.org, as saying. Read more!

Rob Cardinal was looking for an asteroid, but found a comet. / Photo by Leanne Yohemas

Watch a short video of the comet
Comet.wmv or Comet2.mov

Rob Cardinal was looking for an asteroid, but ended up finding a comet. It is the first time a comet has been discovered at U of C’s Rothney Astrophysical Observatory, which is located about 35 kilometres southwest of Calgary, and only the second Canadian discovery of a comet, using a Canadian telescope, in nearly a decade.

On Oct. 1, Cardinal thought he saw something move while observing a patch of sky near the North Celestial Pole while using the observatory's Baker-Nunn telescope. A subsequent computer analysis of the images taken, showed a moving object that although faint by visual standards, was actually exceptionally bright for what was a suspected asteroid at the time.

A few more pictures taken about a week later verified that a never-before-seen member of our solar system had been discovered, and it was confirmed by other observations by astronomers in the U.S. and Japan and the Minor Planet Center, based at Harvard University, that it was a new comet. As per protocol, it was named after Cardinal and is officially designated as C/2008 T2 Cardinal.

“I was so excited when I found out,” says the astronomer. “It’s satisfying to see your hard work pay off.”

Russ Taylor, the head of the physics and astronomy department, called the find a tribute to the team of scientists and the dark sky quality at the observatory.

“Alan Hildebrand, who holds the Canada Research Chair in Planetary Science, and his research team at the Rothney have put together the premier wide-field telescope for space imaging in Canada. The discovery of comet Cardinal is an exciting achievement,” he says.

There is not much known yet about the Cardinal comet. U of C scientists are trying to determine more information about its orbit, whether its passing by Earth is periodic or whether it will only come by the sun once, which would mean its orbit is parabolic.

“The vast majority of the known comets, and the comets now being discovered, are found near a region of the sky called the ecliptic–that's because their orbits are similar to the orbits of the planets,” says Phil Langill, the observatory’s director.

"Comet Cardinal is on a very unusual orbit compared to normal solar system objects–it’s almost 60 degrees out of alignment with all the others. It is currently near the north star. It was brilliant for Alan and Rob to search that part of the sky, because everyone else is looking where the likelihood of asteroid discovery is high."

Cardinal says the comet is visible right now only in the northern hemisphere until June and after that, it will be visible, and likely brighter, in the southern hemisphere.

Langill says that if you could get hold of cometary material, you would be holding a 4.5 billion year old piece of history, with clues about how things were when the Sun and the solar system came together. Comet Cardinal is made up of bits of debris and ice left over when the solar system was created.

Langill adds he credits the local community for remembering to keep their lights off at night. The observatory has been working with the MD of Foothills to educate folks about smart lighting choices, light abatement, and what the astronomers at the U of C’s observatory do.

“This discovery can, in part, be attributable to them,” he says. Read more!

On 56th indepence day, August 15 2003, India's Prime Minister Atal Bihari Vajpayee announced. "Our country is now ready to fly high in the field of science. I am pleased to announce that India will send her own spacecraft to the moon by 2008. It is being named Chandrayaan-1". In Sanskrit (language of Ancient India) "Chandrayaan" means "Moon Craft".

Moon has always fascinated Indians from ancient days and now 21st century india is ready to land on moon! Chandrayaan-1 is the first mission towords the dream.

In Chandrayaan-1, the lunar craft would be launched using Polar Satellite Launch Vehicle (PSLV) weighing 1304 kg at launch and 590 kg at lunar orbit. Lunar craft would orbit around moon 100 km from moon surface.

ISRO inviated international space orgnization to particpate in the project by providing suitable scientific payloads(instrument for experiments). ISRO selected
3 (C1XS, SIR-2, SARA) payload from ESA (European Space Agency)
1 (RADOM) from BSA (Bulgarian Academy of Science),
2 (MiniSAR, M3) from NASA (National Aeronautics and Space Administration)

http://www.chandrayaan-i.com/chandrayaan1/index1.html







Read more!

The country is about to begin its campaign to conquer the moon, setting the tone for its role in a future global effort to colonise earth’s natural satellite. Nirad Mudur reports from Bangalore

On October 22, the Chandrayaan-1 spacecraft is expected to blast off from Sriharikota and aim for the moon, making India join an elite club of a handful of nations to have tried sojourning at the earth’s natural satellite.

Just days ago, action stations at the Indian Space Research Organisation (Isro) moved
Chandrayaan-1 from the Isro Space Applications Centre (Isac) in Bangalore to the Satish Dhawan Space Centre (SDSC) at Sriharikota, about 80km north of Chennai. The spacecraft will orbit the moon for two years at an altitude of 100km before Isro’s scientists will intentionally crash it into the moon’s surface.

Some critics have suggested India is merely reinventing the wheel since the Americans and the Soviets have already done substantial work on the moon, not to speak of their numerous manned moon missions: between 1958 and 1976, the two superpowers carried out 69 unmanned and manned moon missions; the six successful US manned missions, starting with Apollo 11, between 1969 and 1972, and the three USSR missions between 1970 and 1976 were applauded the world over. Contrast this with Isro scientists saying that India is still not equipped to send its own ‘vyomanauts’ (‘vyom’ is ‘space’ in Sanskrit) to the moon.

India may be late, but it has an agenda. “Till now, moon missions have been in localised spaces,” says M Annadurai, mission director, Chandrayaan-1. “But we are planning to cover the entire moon, both sides of it — the one which faces the earth and the one which faces away.” (You may recall from your school science class that the moon rotates around its axis and revolves around the earth in roughly the same time: 28 days. Therefore, one side of the moon always faces the earth while the other always remains hidden.) Read more!

The landmark 10th anniversary of the Hubble Space Telescope's Hubble Heritage Project is being celebrated with a 'landscape' image from the cosmos. Cutting across a nearby star-forming region, called NGC 3324, are the "hills and valleys" of gas and dust displayed in intricate detail. Set amid a backdrop of soft, glowing blue light are wispy tendrils of gas as well as dark trunks of dust that are light-years in height. NGC 3324 is located in the constellation Carina, about 7,200 light-years away from Earth. This image is a composite of data taken with two of Hubble's science instruments. Data taken with the Advanced Camera for Surveys (ACS) in 2006 isolated light emitted by hydrogen. More recent data, taken in 2008 with the Wide Field Planetary Camera 2 (WFPC2), isolated light emitted by sulfur and oxygen gas. To create a color composite, the data from the sulfur filter are represented by red, from the oxygen filter by blue, and from the hydrogen filter by green. http://hubblesite.org/newscenter/archive/releases/2008/34/

Read more!

(CNN) -- Space tourist Richard Garriott has arrived at the International Space Station for a 10-day stay for which he paid the Russian government an estimated $30 million.

Richard Garriott gives the "OK" signal before taking off on a Soyuz rocket for the International Space Station.

A Russian Soyuz spacecraft, which docked with the space station at 4:38 a.m. ET Tuesday, carried Garriott, along with NASA astronaut Michael Fincke and Russian cosmonaut Yuri Lonchakov.

Garriott, a Texan who made a fortune in the video game industry, is the son of former NASA astronaut Owen Garriott.

The elder Garriott, who watched Tuesday's docking at Russia's mission control, flew in 1973 on Skylab, a U.S. forerunner of the International Space Station.

While Richard Garriott said the flight was a fulfillment of his dream to follow in his father's footsteps, he said he will also try to make it a commercial success.

Garriott said he would use the space trip to conduct protein crystal growth experiments for a biotech company co-founded by his father. He is also being paid to wear a watch as a test of its performance in microgravity. Watch Garriott's rocket lift off »

Garriott is the sixth private citizen to buy a ticket to the space station from the Russian government.



BAIKONUR, Kazakhstan (AP) -- A Soyuz spacecraft with two Americans and a Russian on board lifted off from Kazakhstan on Sunday for the international space station.

The Soyuz TMA-13 capsule carrying American computer game millionaire Richard Garriott soared into a clear sky atop a Russian rocket as the latest paying space traveler's family watched from a viewing platform. Also aboard were U.S. astronaut Michael Fincke and Russian cosmonaut Yuri Lonchakov.

The rocket lifted off on schedule at 1:01 p.m. (3:01 a.m. EDT), sending an orange flare behind it as it streaked upward. The craft entered orbit about 10 minutes later.

"I'm elated, elated," said Richard Garriott's father, Owen, a former U.S. astronaut who is the first American to see his child follow in his footsteps and reach space. "They're in orbit, that's good."

Garriott's mother Eve and his girlfriend, Kelly Miller, shed tears of joy and relief at the successful launch.

"This is cool, this is cool," Miller said.

The Soyuz is to dock Tuesday with the international space station, where Garriott will spend about 10 days conducting experiments -- including some whose sponsors helped fund his trip -- and photographing Earth to measure changes since his father snapped pictures from the U.S. station Skylab in 1973.

He is to return to Earth in a Soyuz capsule with cosmonaut Segei Volkov, whose father also traveled to space -- making him the first second-generation space traveler.

Garriott, a Texan who made his fortune designing computer fantasy games, dreamed of space as a child but learned as a youth that he could not become a NASA astronaut because of his poor eyesight. He paid a reported US$30 million for his voyage.

"I'm really happy for him. It's one of the things he's wanted to do most in his life. I spent a lot of time listening to him about when he goes up in space," Miller said.

"He's like a kid in a candy shop," she said. "And I already want him to come back."

Garriott, 47, is a board member and investor in Space Adventures Ltd., a U.S.-based company that has organized flights aboard Russian craft for five other millionaires including the first paying space tourist, California businessman Dennis Tito, in 2001.

The most recent paying traveler, billionaire American software engineer Charles Simonyi, also watched the launch and drank champagne with Garriott's family after the craft reached orbit.

Also on hand was Yi So-yeon, a bioengineer who became South Korea's first astronaut when she traveled to the space station last spring.

Yi and two crew mates had a rough ride back to Earth when their capsule failed to separate on time, sending it into a steep trajectory and subjecting them to powerful gravitational forces in a so-called "ballistic" descent -- the second straight and the third since 2003.

The chief of Russia's space agency Roskosmos, Anatoly Perminov, pledged Saturday that a ballistic landing would not be repeated, and Yi played down any concerns.

"We already had a lot of training for ballistic re-entry, so it's not a big deal," she said, adding that she felt "lucky" to be one of the few people who have had the experience.

"I guess if he also has a ballistic landing, he will feel lucky because he will also be a member of the ballistic landing club," she said.

Perminov said Saturday that increasingly strained ties between Moscow and Washington will not stand in the way of further space exploration. Soyuz rockets and capsules will be the only way to put people on the space station after the U.S. space shuttle fleet is retired in 2010.

Perminov said recent U.S. congressional decisions on future collaboration and the presence of U.S. astronauts at the launch site in Kazakhstan showed that politics would not block cooperation. Congress earlier this month gave NASA permission to purchase seats on Soyuz capsules after 2010. Read more!

Earth atmosphere’s molecules detected by Venus Express

Scientists using ESA’s Venus Express are trying to observe whether Earth is habitable. Silly, you might think, when we know that Earth is richly stocked with life. In fact, far from being a pointless exercise, Venus Express is paving the way for an exciting new era in astronomy.

Venus Express took its first image of Earth with its Visible and Infrared Thermal Imaging Spectrometer (VIRTIS) soon after its launch in November 2005. About a year after the spacecraft established itself in Venus’s orbit, David Grinspoon, a Venus Express Interdisciplinary Scientist from the Denver Museum of Nature & Science, Colorado, suggested a programme of sustained Earth observation.
“When the Earth is in a good position, we observe it two or three times per month,” says Giuseppe Piccioni, Venus Express VIRTIS Co-Principal Investigator, at IASF-INAF, Rome, Italy. The instrument has now amassed approximately 40 images of Earth over the last two years.

The images of Earth cover both visible and near-infrared regions of the spectrum and can be split into spectra, in order to search for the signature of molecules in the Earth’s atmosphere.

The value of the images lies in the fact that Earth spans less than a pixel in Venus Express’s cameras. In other words, it appears as a single dot with no visible surface details. This situation is something that astronomers expect to soon face in their quest for Earth-sized worlds around other stars.

“We want to know what can we discern about the Earth’s habitability based on such observations. Whatever we learn about Earth, we can then apply to the study of other worlds,” says Grinspoon.

Since 1995, astronomers have been discovering these extrasolar planets and now know of more than three hundred. As observational techniques have been refined and the data continuously taken, so smaller and smaller planets have been discovered.

Now, with CNES–ESA’s COROT and NASA’s Kepler missions, the prospect of discovering Earth-sized worlds in Earth-like orbits around other stars is better than ever. “We are now on the verge of finding Earth-like planets,” says Grinspoon.


As has been proved with the discovery of gas giant planets, as soon as astronomers know that they are there, they invent all sorts of innovative methods to separate the planet’s feeble light from the overwhelming glare of the star.

One thing has become obvious from the study of Earth using Venus Express: determining whether a planet is habitable is not going to be easy. “We see water and molecular oxygen in Earth’s atmosphere, but Venus also shows these signatures. So looking at these molecules is not enough,” says Piccioni.

Instead, astronomers are going to have to search for more subtle signals, perhaps the so-called red edge caused by photosynthetic life. “Green plants are bright in the near infrared,” says Grinspoon. The analysis to see whether this red edge is visible is just beginning.

The team will also compare spectra of the Earth’s oceans with those taken when the continents are facing Venus Express. “We have initiated the first sustained programme of Earth observation from a distant platform,” says Grinspoon. Although the observations may not tell us anything new about the Earth, they will allow us to unveil far-off worlds, making them seem more real than simply dots of light.


For more information:

David Grinspoon, Venus Express interdisciplinary scientist, Denver Museum of Nature & Science, Colorado, USA
Email: David.Grinspoon @ dmns.org

Giuseppe Piccioni, VIRTIS co-Principal Investigator, IASF-INAF, Rome, Italy
Email: Giuseppe.piccioni @ iasf-roma.inaf.it

Pierre Drossart, VIRTIS co-Principal Investigator, Observatoire de Paris-LESIA, France
Email: Pierre.Drossart @ obspm.fr

Håkan Svedhem, ESA Venus Express Project Scientist
Email: Hakan.Svedhem @ esa.int Read more!

On 7 October, asteroid 2008 TC3 hit Earth and exploded in the atmosphere over northern Sudan. Amazingly, the Meteosat-8 Rapid Scanning Service managed to capture the impact.

There was a spectacular show in the sky early Tuesday morning when a small asteroid entered the earth's atmosphere, releasing a huge amount of light and energy before exploding. This brief flash was captured by Meteosat-8 in Rapid Scan Service, as the image to the left shows. (IR3.9 channel, 7 October 2008 at 02:45:47 UTC).

The asteroid 2008 TC3 entered the Earth's atmosphere at a velocity of 12.8 kilometres per second at around 02:46 UTC above northern Sudan, Africa. As it entered the Earth’s atmosphere, it compressed the air in front of it. The compression heated the air, which in turn heated the object to create a spectacular fireball, releasing huge amounts of energy as it disintegrated and exploded in the atmosphere, dozens of kilometres above ground.

The asteroid exploded with the energy of around one kiloton, equal to the power of a small nuclear bomb. Infrasound detector arrays in Kenya also detected a sound wave from the direction of the expected impact corresponding to the energy of 1.1-2.1 kilotons of TNT.

2008 TC3 was discovered on 6 October by astronomers using the Mt. Lemmon telescope in Arizona as part of the NASA-funded Catalina Sky Survey for near-Earth objects. Asteroids the size of 2008 TC3 hit Earth a few times a year, but what is special about this event is that it is the first time one has been discovered before it hit. The estimated time of arrival was also precise. At 01:45 UTC, JPL scientist Paul Chodas announced, "We estimate that this object will enter the Earth's atmosphere at around 2:45:28 UTC and reach maximum deceleration around 2:45:54 UTC at an altitude of about 14 km. These times are uncertain by +/-15 seconds or so." The figure on the left shows the predicted impact point. (Credit: Peter Brown, University of Western Ontario).

Half an hour before the predicted impact, Jacob Kuiper, general aviation meteorologist at the Koninklijk Nederlands Meteorologisch Instituut (KNMI), the Dutch weather service, informed an official of Air France-KLM at Amsterdam airport about the possibility that crews of its airliners in the vicinity of the impact would have a chance of seeing a fireball. And it was a success! A KLM airliner roughly 1,400 km south-west of the predicted atmospheric impact position observed a short bright flash just before the expected impact time.

The images taken by Meteosat-8 confirm that the asteroid entered the atmosphere exactly as estimated. Read more!

A team of internationally renowned astronomers and opticians may have found a way to make "unbelievably large" telescopes on the Moon.

"It's so simple," says Ermanno F. Borra, physics professor at the Optics Laboratory of Laval University in Quebec, Canada. "Isaac Newton knew that any liquid, if put into a shallow container and set spinning, naturally assumes a parabolic shape—the same shape needed by a telescope mirror to bring starlight to a focus. This could be the key to making a giant lunar observatory."

Borra, who has been studying liquid-mirror telescopes since 1992, and Simon P. "Pete" Worden, now director of NASA Ames Research Center, are members of a team taking the idea for a spin.

Right: An artist's concept of a spinning liquid mirror telescope on the Moon. Credit: Univ. of British Columbia.

On Earth, a liquid mirror can be made quite smooth and perfect if it its container is kept exactly horizontal and rests on a low-vibration low-friction air bearing that is spun by a synchronous motor having one stable speed. "It doesn't need to spin very fast," says Borra. "The rim of a 4-meter–diameter mirror—the largest I've made in my lab—travels only 3 miles per hour, about the speed of a brisk walk. In the low gravity of the Moon, it would spin even slower."

Most liquid-mirror telescopes on Earth have used mercury. Mercury remains molten at room temperature, and it reflects about 75 percent of incoming light, almost as good as silver. The biggest liquid-mirror telescope on Earth, the Large Zenith Telescope operated by the University of British Columbia in Canada, is 6 meters across—a diameter 20 percent larger than the famous 200-inch mirror of the Hale telescope at Palomar Observatory in California. Yet when completed in 2005, the Canadian Palomar-class liquid-mirror telescope cost less than $1 million to build—only a few percent the cost of a solid-mirror telescope of the same diameter--and, for that matter, only a sixth of Palomar's original cost in 1948.

Those economics are making astronomers sit up and begin noodling out plans for a lunar observatory.

"Our study [with Borra] started when I was still an astronomy professor at the University of Arizona before I came to NASA in 2006," Worden recalls. "The real appeal of this approach is that we could get an unbelievably large telescope on the Moon."

Mercury is unworkable on the Moon: it's very dense and thus heavy to launch, it's very expensive, and it would evaporate quickly when exposed to the lunar vacuum. In recent years, however, Borra and his colleagues have been experimenting with a class of organic compounds known as ionic liquids. "Ionic liquids are basically molten salts," Borra explains. "Their evaporation rate is almost zero, so they would not vaporize in the lunar vacuum. They can also remain liquid at very low temperatures." He and his colleagues are now seeking to synthesize ionic liquids that remain molten even at liquid-nitrogen temperatures.

Below: The University of British Columbia's 6-meter Large Zenith Telescope uses a liquid mirror to scan the heavens. [more]

Much less dense than mercury, ionic liquids are only slightly denser than water. Although not highly reflective themselves, a spinning mirror of an ionic liquid can be coated with an ultrathin layer of silver just as if it were a solid mirror. Weirdest of all, the silver layer is so thin—only 50 to 100 nanometers—that it actually solidifies. In the vacuum of space, a liquid mirror coated with a thin solid layer of silver would neither evaporate nor tarnish.

A liquid mirror can't be tilted away from the horizontal because the fluid would pour out, destroying the mirror. But that does not mean a liquid mirror telescope cannot be pointed. Optical designers are now experimenting with ways of electromechanically warping secondary mirrors suspended above a liquid mirror—or even slightly warping the liquid mirror itself—to aim at angles away from the vertical. Similar techniques are used to point the great Arecibo radio telescope in Puerto Rico.

Furthermore, says Borra, "if the telescope is located anywhere other than exactly at the poles, with each rotation of Earth or Moon it would scan a circular strip of sky. And the rotational axis of the Moon wobbles with a period of 18.6 years; so over a period of 18.6 years, the telescope would actually look at a good-sized region of the sky."

Right: The 1000-ft Arecibo radio telescope in Puerto Rico cannot be moved, but it can still scan a wide swath of sky using movable secondary mirrors. A lunar liquid mirror telescope might employ similar techniques. [more]

Locating a major liquid-mirror telescope near the lunar poles is appealing. The telescope itself could reside near the bottom of a permanently shadowed crater where it would stay at cryogenic temperatures, desirable for the best infrared astronomy. Yet solar panels could be erected on nearby permanently illuminated mountain peaks to generate power to keep the mirror spinning.

The fact that a liquid-mirror telescope always looks straight up vastly simplifies its construction and reduces mass by eliminating heavy mounts, gearing, and pointing-control systems needed for a steerable telescope. "All you'd need is the liquid-mirror container, which might be an umbrella-like device that self-deploys, plus a nearly frictionless superconducting bearing and its drive motor," Borra says. Worden estimates that all the materials for an entire lunar telescope 20 meters across would be "only a few tons, which could be boosted to the Moon in a single Ares 5 mission in the 2020s." Future telescopes might have mirrors as large as 100 meters in diameter—larger than a football field.

"A mirror that large could peer back in time to when the universe was very young, only half a billion years old, when the first generation of stars and galaxies were forming," Borra exclaimed. "Potentially more exciting is pure serendipity: new things we might discover that we just don't expect."

Says Worden: "Putting a giant telescope on the Moon has always been an idea of science fiction, but it soon could become fact."

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Yesterday, NASA's MESSENGER spacecraft flew past Mercury and photographed a broad swath of never-before-seen terrain. The first of more than 1,200 high-resolution images are arriving back at Earth now.

"The MESSENGER team is extremely pleased by the superb performance of the spacecraft and the payload," says MESSENGER Principal Investigator Sean Solomon of the Carnegie Institution of Washington. "We are now on the correct trajectory for eventual insertion into orbit around Mercury, and all of our instruments returned data as planned."

This spectacular image – one of the first to be returned – was snapped by the spacecraft's Wide Angle Camera (WAC) about 90 minutes after MESSENGER's closest approach to Mercury, when the spacecraft was at a distance of about 27,000 kilometers.

he most striking characteristic of this newly imaged area is the large pattern of rays streaking downward from the planet's northern regions. The ray system appears to emanate from a relatively young crater previously seen in Earth-based radar images but photographed by a spacecraft for the very first time just yesterday. This view of the planet is distinctly unique from what MESSENGER saw during its first flyby in Jan. 2008.

In the mid-1970s when Mariner 10 flew past Mercury three times, the probe imaged less than half the planet. MESSENGER's first flyby in January of this year covered another 20 percent of the planet's surface. Yesterday, Oct. 6th, MESSENGER successfully completed its second flyby of Mercury, unveiling another 30 percent of Mercury's surface that had never before been seen by spacecraft.

"When these data have been digested and compared, we will have a global perspective of Mercury for the first time," notes Solomon.

Data from the flyby continue to stream down to Earth, including higher resolution close-up images of this previously unseen terrain.

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