Magnetic forces behind northern lights explained

A fleet of five small satellites, called Themis, observed the beginning of a geomagnetic storm in February, while ground observatories recorded the brightening of the northern lights.

A team led by UCLA scientist Vassilis Angelopoulos confirmed that the observed storm about 80,000 miles from Earth was triggered by a phenomenon known as magnetic reconnection. Every so often, the Earth's magnetic field lines are stretched like rubber bands by solar energy, snap, are thrown back to Earth and reconnect, in effect creating a short circuit.

This stored-up energy powers the northern and southern lights, Angelopoulos said.

Low sperm count, soy foods linked

Eating half a serving per day of soy-based foods could significantly lower a man's sperm count, Harvard researchers reported Wednesday in the journal Human Reproduction.

The study is the largest in humans to look at the relationship between semen quality and a plant form of the female sex hormone estrogen known as phytoestrogen, which is plentiful in soy-rich foods.

From Times Staff and Wire Reports