Supernovae give us clues about the expansion of the Universe

Two international teams of astronomers provided a glimpse into the destiny of the Universe when they looked at distant stars and found that they were rushing apart at an accelerating rate.

Scientists discovered decades ago that the Universe has been expanding since the Big Bang. But whether the gravitational pull between galaxies could slow, and ultimately reverse, that expansion has been unknown.

This year's discovery showed that the expansion of the Universe is in fact speeding up. This implies that gravity is no match for the force that is pushing the Universe outwards in all directions, and that the expansion may continue, perhaps forever.

Number two

The runner-up for most important advance of the year concerns work on the nature of circadian rhythms. Almost every organism on Earth keeps track of the 24-hour cycle between night and day using its "circadian clock", a built-in mechanism that researchers found out a lot about in 1998.

Even bacteria tell the time

A quick succession of discoveries shed light on how the molecular "gears" driving the circadian clock respond to light and temperature cues and how they work together in different organisms. The results showed a surprising similarity between clock workings in organisms from bacteria to humans.

Remarkably, it appears that fruit flies and mice - separated by nearly 700 million years of evolution - share the same timekeeping proteins. Once again science has shown us how closely related is all life on Earth.

These developments may ultimately provide insight into overcoming jet lag and winter depression.

Best of the rest

• Nerve messenger - In 1998 researchers were finally able to answer an essential question about how cell membranes manage to allow in or out certain ions that are essential for sending messages along nerves.

• Combinational chemistry - They also continued to stretch the applications of combinatorial chemistry. This technique allows researchers to make and test hundreds of thousands of new compounds at once. It was used to produce new molecules for drug discovery and also to develop fuel cell catalysts and other industrial compounds.

  C. elegans: The first animal to have its genome completely sequenced

• Tiny worm - 1998 was also a landmark year in the sequencing of several microbial genetic blueprints. The tiny C. elegans worm has long been a workhorse for a wide variety of biological research topics, and at the close of the year its genome was the first from a multi-cellular animal to be sequenced.

  The genetic information obtained may eventually allow researchers to break new ground in understanding the evolutionary relationships among organisms.

• Neutrino mass - For years researchers have been on the trail of neutrinos, strange and ghostly sub-atomic particles that are of fundamental importance in the makeup of the universe.

  They were long thought to have no mass. This year an international team using the Super-Kamiokande neutrino detector in Japan claimed to have found evidence that neutrinos do have mass.

  It is a discovery which, if it holds up, should prompt a rethinking of the prevailing theory of the forces and particles that make up the Universe.

• Micromachines - In 1998 researchers married biological research tools with microchip technology to create a flurry of novel micromachines. These tiny gadgets can do the work of many lab technicians at once, performing tasks including processing DNA, screening blood samples, scanning for disease genes, and surveying gene activity in cells.

  Major microelectronics firms have now entered the biochip business after taking notice of this technology's potential.

• Quantum leaps - It was not exactly "Beam me up Scotty", but this year researchers in the US and Europe teleported information about the quantum state of a particle to a different location, where it was used to help recreate an identical particle.

  It is a far cry from Star Trek's transporter but this achievement is key for creating quantum computers, ultra-powerful machines that will one day offer incredible computing speed and power.