Bon voyage

NASA's Voyager 1 spacecraft has left the Solar System — probably. Space scientists are still quibbling about whether the probe has or hasn't actually crossed the critical boundary, called the terminal shock layer, where the solar wind hits the interstellar medium. Either way, Voyager is now 13.5 billion kilometres away from us — about 90 times the distance between Earth and the Sun. It should reach the next nearest star in 40,000 years.

Meet the ancestors

Fossils found near the village of Herto in Ethiopia were revealed to be the oldest yet of modern Homo sapiens. The skulls — of two adults and a child who lived 160,000 years ago — support the idea that modern humans originated in Africa, and that Neanderthals were a branch of the human evolutionary tree that later went extinct. Cut marks on the skulls suggest that the first modern humans had some mortuary practices. And marks on nearby animal bones suggest that these people may have dined on hippopotamuses.

Condensed matter

Two teams of physicists cracked the problem of making Bose–Einstein condensates out of molecules rather than atoms. Such condensates are a strange state of matter in which the constituent particles occupy the same quantum state and so behave as a single particle. Atomic condensates were achieved in 1995, but their molecular equivalents proved a harder nut to crack. By cooling atoms with a laser and squeezing them together with magnetic fields, researchers managed to create loose molecular bonds — the molecules then collapsed into a condensate.

Look, no gonads!

Both eggs and sperm were produced in the lab from mouse embryonic stem cells. Sperm cells, which were grown in culture from male embryonic cells, were even used successfully to fertilize natural mouse eggs. The lab-made eggs were, intriguingly, grown from both female and male cells. The ability to grow eggs in a dish should provide a boost for studies of fertility and cloning — if they turn out to be normal.

Blow up

The origins of long γ-ray bursts — which last longer than a few seconds — were pinned down at last. These bursts are some of the most energetic events in the Universe. Astronomers witnessed the death of a massive star and recorded a γ-ray burst from the same event. The spectacular stellar show proved that some, if not all, long γ-ray bursts are associated with supernovae, the catastrophic explosions that end the lives of the largest stars. The origin of shorter γ-ray bursts remains a mystery.