Surprising data from NASA's Stardust programme has revealed that comets have heat-formed components.

Scientists analysing samples from the seven-year mission to collect material from the tail of comet Wild 2 found glassy particles that must have been formed at high temperatures. Stardust curator Michael Zolensky said: "It seems that comets are a mixture of materials formed at all temperatures, at places very near the early sun and at places very remote from it."

Stardust principal investigator Donald Brownlee spelt out the paradox of the finding: "The interesting thing is we are finding these high-temperature minerals in materials from the coldest place in the solar system."

Stardust returned to Earth in the Utah desert back in January. Next for the international community of 150 scientists working on the samples is to examine the interstellar dust material the probe returned. ®

Related stories

• NASA probes underwater operations (30 March 2006)
• NASA deploys satellite swarm (23 March 2006)
• Stardust floats gently to Earth (16 January 2006)
• Situations vacant for eagle-eyed stardust spotters (12 January 2006)
• Countdown to launch for Deep Impact (11 January 2005)