杏吧原创

1 Brain atlas

It鈥檚 biology鈥檚 final frontier. The brain is the most complex organ in the human body and much of it is still uncharted territory. Despite decades of research, scientists are still unclear about the anatomical boundaries of some of the different brain regions, let alone the finer detail. What we need is a really good map 鈥� and that鈥檚 what the Seattle-based Allen Institute for Brain Science is working on.

Set up last year with $100 million from Microsoft co-founder Paul Allen, the organisation鈥檚 first goal is to produce the Allen Brain Atlas. This will be a three-dimensional map of gene expression that will show which neurons make which neurotransmitters and other chemicals, to help divide the brain into functional regions.

The team is using the mouse brain, as many mouse genes are already known and inbred lab strains can be used that are almost genetically identical. Apart from higher cognitive functions, many of the workings of the mouse brain are shared with humans. The map-making process itself is likely to yield numerous discoveries, but it will also be an invaluable resource for other scientists.

The researchers aim to chart all the genes expressed in the brain 鈥� up to 20,000 鈥� through a technique called 鈥渋n situ hybridisation鈥�. This involves bathing a thin slice of tissue in a solution of chemically labelled DNA or RNA that binds to or is 鈥渃omplementary鈥� to the messenger RNA for each gene, showing in which cells it is switched on and making protein. The Allen team will do this for numerous brain slices to build up a 3D atlas with resolution down to the cellular level. They will start with genes with known functions but will have to characterise many new ones.

The huge task is likely to take five years, but data will be put online in quarterly updates, with the results for the first few hundred genes ready by June. Expect some interesting signposts to the way ahead.

2 Venus transit

On 8 June, 5 billion people will be treated to a sight no living person has ever seen 鈥� the planet Venus passing across the face of the sun. The last time this happened was in 1882.

The transit will last about 6 hours and will be visible from just about everywhere in the world except for a few regions in and around the Pacific. With an appropriate filter to protect your eyes, such as the eclipse-viewing glasses available during the last solar eclipse, Venus will appear as a round black dot crossing the sun鈥檚 bright face.

Astronomers first observed a transit of Venus in 1639, and there have only been four since then. They occur in pairs, eight years apart, once every 120 years or so. After this year鈥檚 transit there will be another in 2012.

Historically, transits of Venus were a source of great excitement for astronomers. The English astronomer Edmund Halley realised that by timing how long it took Venus to cross the sun鈥檚 disc in different parts of the world, it was possible to calculate the distance to the sun from simple geometry. That, in turn, allowed astronomers to calibrate the distances to all the planets.

With this in mind, scientists sailed to remote corners of the globe to measure transits of Venus in 1761 and 1769. Some expeditions met with disaster. Crew members were killed in crossfire from the seven years war between England and France. Some died in epidemics or became prisoners of war. Others reached their destination in time for the transit, only to find cloudy skies that made their trip pointless. One Frenchman returned home after almost 12 years to find is relatives had sold off his possessions, assuming he was dead.

But some, including the British explorer Captain James Cook who was in Tahiti for the transit of 1769, got excellent measurements. Combined with the 1761 measurement, Cook鈥檚 result gave astronomers their first accurate value for the sun鈥檚 distance 鈥� within 1 per cent of the modern figure of 149,598,000 kilometres, made by bouncing radar off the surface of Venus.

This year, the European Southern Observatory is coordinating a programme it hopes will encourage millions of people to follow in these pioneers鈥� footsteps and work out the sun鈥檚 distance for themselves.

3 Other worlds

NASA鈥檚 Martian landers have already got 2004 off to a nail-biting start, but the world of space exploration will have another two tense moments later this year when the journey of one big-budget spacecraft ends and another begins. In February, the European Space Agency hopes to send off its comet-chasing spacecraft Rosetta. And in July, NASA鈥檚 Cassini spacecraft 鈥� the largest interplanetary probe ever built 鈥� will reach its destination, Saturn.

Rosetta is the first probe designed to orbit a comet and drop a landing craft onto its nucleus. The billion-euro spacecraft was originally scheduled for launch in January 2003 aboard an Ariane 5 rocket. After an eight-year journey, it was due to rendezvous with a comet called Wirtanen in 2011.

But when an Ariane 5 rocket failed in December 2002, ESA took fright and put Rosetta on ice. Now the plan is to launch it on 26 February, this time with a different target, comet Churyumov-Gerasimenko (or 鈥淐hury鈥�).

杏吧原创s will have to wait until 2014 for Rosetta to reach the comet. But some say the extra wait will pay off because Chury is about four times as wide as Wirtanen, making it a much more spectacular comet. Rosetta will circle Chury as the comet journeys into the inner solar system and starts to fizzle in the sun鈥檚 radiation.

As Rosetta鈥檚 journey begins, the Cassini spacecraft will be nearing its destination. Launched in 1997, the $3.4 billion spacecraft is as high as a two-storey building. Cassini will have travelled about 3.2 billion kilometres when it goes into orbit around Saturn on 1 July. It will remain there for four years, exploring the planet, its magnificent ring system and its myriad moons.

On Christmas day, a probe called Huygens built by ESA will separate from the orbiter and head for Titan, Saturn鈥檚 largest and most intriguing moon. Titan is the only moon in the solar system with an atmosphere 鈥� at its surface the atmospheric pressure is 60 per cent higher than Earth鈥檚 鈥� and astronomers suspect there are seas of methane, hidden from view by dense clouds. They won鈥檛 have to wait long to find out: Huygens is due to touch down on Titan three weeks later.

4 Nationwide quantum network

Singapore is hoping to become the first nation with a nationwide network of communication channels protected by quantum cryptography. Of course, it won鈥檛 be quite as difficult for this small island state as it might be for some nations, but it would still represent a significant achievement.

The security of quantum cryptography relies on the properties of 鈥渆ntangled鈥� pairs of photons to carry the key that protects data. The fragile nature of quantum entanglement means that once the key has been established, those exchanging information can be assured that no one can read their secrets undetected.

The initial step, scheduled for the first half of this year, will be a joint effort by the National University of Singapore, Nanyang Technological University and the government-funded A^*STAR agency and the defence-focused Temasek Laboratories. They will send photons through the air from the rooftop of one skyscraper and pick them up using detectors on another a kilometre away. The team will start by transmitting single photons, only moving on to entangled pairs once they have learned how to overcome their main obstacle: the weather.

The initial experiments will investigate how efficiently the photons can be detected through air turbulence, wind and rain. Skyscrapers sway, so even moderate winds could push the detector out of the photons鈥� path. To overcome this, the researchers may need to integrate motion-tracking technology into the standard cryptography set-up.

Once these challenges have been met, the team believes it will be relatively straightforward to establish a quantum network across the island. The researchers aim to create a star-shaped network, with photons beamed to and from a central hub. Representatives of Singapore鈥檚 ministry of defence and the country鈥檚 industrial and banking communities will be watching the demonstration with interest.

5 Son of hubble

Astronomers may have to wait until 2011 for the first images from the Hubble space telescope鈥檚 successor, but work on its main mirror will start in earnest this year. When complete, the James Webb Space Telescope will be 2.5 times the diameter of Hubble yet will weigh just one-third as much. To keep the weight down, NASA has opted to build the mirror from 18 lightweight beryllium hexagons, each measuring 1.3 metres across. Once the craft has reached its final destination 1.5 million kilometres from Earth, these will unfold to create a mirror 6.5 metres in diameter.

With such a large mirror, the Webb telescope will be able to see distant objects 400 times fainter than those studied with the largest ground-based telescopes, including the first generation of stars born a few hundred million years after the big bang. And unlike its predecessor it will be able to peer through the gas and dust that hides young stars and planetary systems, observing mostly at infrared wavelengths that can penetrate thick veils of cloud.

To prevent infrared radiation from the sun and Earth swamping its detectors, the Webb telescope will also be fitted with a giant sunshade. When it is unfurled 鈥� at the same time as its mirror and solar panels 鈥� the shade will be as large as a tennis court and will keep the telescope chilled to 35 kelvin. Hubble doesn鈥檛 need cooling because it observes visible and ultraviolet wavelengths.

Northrop Grumman, the California-based company selected by NASA to build the mirror, is taking every precaution to avoid the problem that dogged Hubble鈥檚 first three years in space. A flaw in Hubble鈥檚 main mirror dashed hopes of producing sharp, detailed images of distant galaxies, until astronauts on board the space shuttle Endeavour installed instruments to correct the defect. With the Webb telescope orbiting almost four times farther away than the moon, a similar rescue mission would be impossible.

6 Atkins verdict

Here鈥檚 a prediction you can put money on. There will be a lot more fuss about the Atkins diet.

This controversial weight-loss programme, much loved by celebrities, turns conventional wisdom on its head by allowing people to eat as much protein and fat as they like but not carbohydrates. A team of doctors at the University of Pennsylvania is poring over the data from the biggest medical test yet for Atkins, comparing it with a conventional calorie-controlled diet in a group of 132 people. They will soon report their verdict 鈥� whether Atkins promotes weight loss as successfully as it promotes itself.

But didn鈥檛 a study last year give Atkins the definitive thumbs-up? No, although you could be forgiven for getting that impression. In May, researchers announced results from two clinical trials, one lasting six months and a smaller one lasting a year. Both showed that the Atkins dieters got a head start, reporting greater loss in the first three to six months than a control group. But at the end of the year-long trial there was no significant difference between the groups.

Unfortunately these studies were either too small or too short to allow the researchers to draw statistically sound conclusions. But the larger study has continued for another six months, and those results 鈥� due next year 鈥� will be more conclusive.

7 Giant telescope

By the end of this year, there will be a new eye trained on the skies 鈥� one that promises to overcome the policies of past South African governments that excluded black people from science and technology. The $30 million Southern African Large Telescope is due for completion in December, and will be the largest single optical telescope in the southern hemisphere. Sited at Sutherland in the Northern Cape province of South Africa, SALT was proposed by the South African government as a way to enable the country鈥檚 researchers to pursue world-class science while also raising its standards in science, technology and engineering.

One of the partners involved in the telescope, Rutgers University in New Jersey, has already begun a programme of training black South African PhD students in astronomy techniques. And some 60 per cent of the telescope鈥檚 construction costs are being spent in South Africa. Companies tendering for a slice of the work were asked to specify to what extent they are black-owned and what programmes they have in place for developing skills in disadvantaged communities.

When completed, SALT will sport a hexagonal mirror array 11 metres across. It will record distant stars, galaxies and quasars a billion times fainter than objects visible to the naked eye. This will enable SALT astronomers to carry out spectroscopic studies on the light from distant celestial objects and will add to cosmologists鈥� studies of the early universe. The SALT astronomers, who will carry out observations on behalf of any researchers granted telescope time, are also planning to look for gamma-ray bursters and extra-solar planets.

8 Bitter blocker

Last summer, food scientist Beverly Tepper hosted a bizarre drinks party in her lab at Rutgers University in New Jersey. She took the most acrid drinks she could find 鈥� black coffee and grapefruit juice 鈥� and removed all the bitterness simply by stirring in a tiny amount of an ordinary-looking white powder.

It wasn鈥檛 a sweetener but a 鈥渂itter blocker鈥�, a chemical designed to stop human taste buds from detecting bitter flavours (New 杏吧原创, 1 March 2003, p 14). Manufacturer Linguagen of Cranbury, New Jersey, has gained clearance for the compound and the first products containing bitter blockers will hit the shelves this year.

That鈥檚 good news if you eat a lot of pre-prepared foods. Food processing tends to intensify bitter flavours, so food companies mask them with lashings of salt, fat and sugar. A pinch of bitter blocker 鈥� about 400 parts per million 鈥� makes these additives unnecessary. Linguagen鈥檚 pioneering bitter blocker, adenosine monophosphate (AMP), is likely to find its way into all sorts of food products.

Bitter foods get their taste from a cascade of biochemical reactions. When taste receptor cells in the mouth detect bitter compounds, they release a protein called gustducin that triggers a series of reactions. AMP stops the release of gustducin by bonding to the taste receptors in place of the bitter compounds.

Both Linguagen and its competitor Senomyx of La Jolla, California, are working on more potent blockers for another valuable market 鈥� masking the extreme bitterness of many widely used pharmaceuticals such as cough and cold remedies and anti-ulcer drugs.

Bitter blockers definitely work, says Tepper. Adding AMP to coffee brought out its roasted flavours, she says, while the grapefruit juice had much more of a citrus tang.

9 Solar sailing

A rocket carrying the first spacecraft driven by a solar sail will break the surface of the Barents Sea later this year, shot into orbit from a converted Russian nuclear submarine. The three-stage rocket will deposit a modest craft called Cosmos 1 in an orbit high above the international space station. Within a few days, the craft will unfurl eight shiny Mylar sails each measuring 14 metres across. These will harness the radiation pressure of photons streaming from the sun to lift the craft to higher orbits.

It will be a proud day for Louis Friedman, director of the California-based Planetary Society, who has been dreaming of setting sail in space for more than 25 years. In 1975, Friedman headed NASA鈥檚 effort to rendezvous with Halley鈥檚 comet using a solar sail-powered craft. But the mission was grounded because it was based on untested technology and thought to be too risky. Now media company Cosmos Studios is backing this much less ambitious mission, whose only goal is to prove the solar sail concept.

The aim for Cosmos 1 is to survive just a few kilometres with a flimsy unfurled sail, enough for mission operators to measure how far the spacecraft climbs with the sun鈥檚 photons in its sails. The next step will be to measure the speed of ions in the solar wind as they move around the sail, and to aim a beam of high-energy microwave photons at the sail from Earth to measure its effect on the craft鈥檚 orbit.

A successful solar sailing mission will boost the prospect of missions designed to collect samples from elsewhere in the solar system and return them to Earth. That鈥檚 because a spacecraft powered by a solar sail would need far less fuel than one that uses conventional rockets. It may not be long before a mission to bring back samples from Mercury, or even some of the outer planets, could appear on the drawing board.

10 Hunt for atlantis

It could be 2004鈥檚 most fabulous expedition: a voyage to the lost world of Atlantis. But the people planning it are no crystal-waving cranks. A team of underwater archaeologists has pinpointed a submerged island whose features match some of Plato鈥檚 legendary description. They hope to find evidence that prehistoric hunter-gatherers lived there before the island flooded at the end of the last ice age.

Jacques Collina-Girard, an archaeologist at the University of Aix-en-Provence in France, first suggested the idea back in 2001 while studying human migration patterns during the last ice age. To see whether prehistoric people could have crossed from Europe into North Africa, he reconstructed a map of the western European coastline some 19,000 years ago, when the sea level was 130 metres lower than it is now. The map revealed an archipelago whose largest island, called Spartel, lay just west of the Strait of Gibraltar, the spot described by Plato (New 杏吧原创, 22 September 2001, p 17).

What鈥檚 more, the time given by Plato for Atlantis鈥檚 watery demise 鈥� 11,000 years ago 鈥� matches records from coral reefs suggesting that the postglacial rise in sea levels accelerated briefly to 2 metres per century around the same time. Such a rise could have inundated Spartel and helped to foster tales of a flooded island that eventually inspired Plato鈥檚 myth.

Collina-Girard has teamed up with Paul Henri Nargeolet and George Tulloch, the underwater explorers who discovered the wreck of the Titanic. They will head for Spartel in July and use a manned submersible to explore the hilly island, which lies between 55 and 200 metres under water. The preliminary survey will take 10 days and will involve mapping the island with sonar and sampling sediments for dating.

They may also find archaeological sites, says Collina-Girard, but this would depend on the team finding caves with sediments that can be sampled for flint tools. If they strike it lucky, the team will have discovered the first underwater coastal archaeological site.