Nasa’s Jet Propulsion Laboratory has landed robotic explorers on the surface of Mars, sent probes to outer planets and operates a worldwide network of antennae that communicates with interplanetary spacecraft.

The US government may resume funding of embryonic stem cell research for now, an appeals court said, but the short-term approval may be of little help to research scientists caught in a legal battle that has just begun.

Hundreds of same-sex marriages kept San Francisco City Hall offices open and buzzing through the weekend, with gay and lesbian couples waiting hours to exchange vows and conservative activists promising a relentless legal challenge.

Gay and lesbian couples rushed to San Francisco to celebrate Valentine’s Day with weddings at City Hall today as officials continued to defy state law by issuing marriage licences to same-sex partners.