NEPTUNE DIAMONDS. The crushing conditions inside Neptune and Uranus are recreated at UC Berkeley, where a tiny sample of methane is squeezed in a diamond anvil press up to pressures of 30-50 GPa (more than 0.5 million atm) and heated with laser light to temperatures to 3000 K. Scattered x rays and infrared light indicate that some of the methane is being converted into 10-micron-sized diamonds and certain polymers at pressures much below what had been expected. This result might lead to some re-assessment of planetary interiors since a widespread dissociation of methane would release considerable energy, affecting the dynamics and evolution of the planet in a big way. (Benedetti et al., Science, 1 October 1999.)