Jumps in space-time might explain the curious survival of energetic particles.

Space and time must be grainy, not smooth. Otherwise high-energy particles produced in astrophysical processes would not be detectable on Earth.

So says Richard Lieu of the University of Alabama in Huntsville. Many agree that jumps in space-time occur on scales that are far too small to measure, but the idea has not yet been proved. Lieu now shows that using this hypothesis can explain how highly

Fruit’s hidden colour reveals whether it will ripen.

Some green tomatoes have a rosy future; others do not. A sensor that picks up subtle differences in the light the fruits reflect could sort future salads from greens.

Many tomatoes are picked green and bathed in ripening gas ethylene. Fruit picked too early will never ripen. Discerning consumers avoid them and growers lose out.

A scanner that analyses the wavelengths green tomatoes bounce back can predict th

New algorithm exploits community structure of the web.

The web has spontaneously organized itself into communities. A new search algorithm that pinpoints these could help surfers find what they want and avoid offensive content.

Page builders can link anywhere. But they don’t, Gary Flake, of the NEC Research Institute in Princeton, and his colleagues have found. Instead, pages congregate into social groups that focus most of their attention on each other.

Web dir

Early humans came out of Africa again and again.

There were at least three major waves of early human migration out of Africa, our DNA suggests. Apparently the wanderers made love, not war: gene patterns hint that later emigrants bred with residents.

Human origins are contentious. Most researchers agree that there have been several major migrations out of Africa. Some hold that human populations in many regions evolved in parallel after Homo erectus left Africa around two mi

Gloves are coming off in ancient bacteria bust-up.

A claim to have found evidence of the oldest living things on Earth is being fiercely contested. The argument looks set to run and run, and no one may win, but it may lead to a better understanding of the origins of life on our planet.

The debate is academic, but its implications are not. The ’fossil bacteria’ in question are around 3.5 billion years old. That’s roughly one billion years older than the only confirmed fossil

Scientists at Umeå University in Sweden are putting forward an entirely new picture of climate change and the first immigration of trees following the last Ice Age. Research shows that 8,000-14,000 years ago the climate was considerably warmer than was previously thought. When it was at its warmest 9,000-10,000 years ago, the timberline was 500 m higher than today, and leafy trees grew in the mountains. The spruce immigrated considerably earlier that was assumed until now, and it probably came from t