Unexplained phenomenon

A UFO from District 9

Unexplained phenomenon: A UFO from District 9. Photograph: PR

The fact the Guardian's Bad Science column has now surpassed 300 articles may indicate that the public's interest in debunking myths is nearly as voracious as their appetite for the paranormal and unexplained - the subject of a special edition Google logo today.

The image used is of an ascending UFO - familiar to us all from the X-files and Doctor Who, and soon as the subject of the new film District 9, ascience fiction thriller in which ugly aliens invade South Africa and are herded into a slum.

But statistics released by the National Archives this August would suggest the silver screen is not the only place we are seeing UFOs. Sightings are not as rare a sighting as you might expect, with over 800 reports being detailed between 1993 and 1996.

This August's publication is the fourth batch of data released by the National Archives on this topic. It also details crop circles and shows reports relating to different areas of Britain - with explanations of what may have caused lights. Simon Rogers helpfully extracted 50 of the most interesting ones to look at in his datablog.

The explanations given for each incident indicate that the MoD do not spend a great deal entertaining the thought of extraterrestrial life. But Alokh Jha met astrobiologist Dr Lewis Dartnell from University College London to speculate about what form life might take elsewhere in the Solar System and beyond.

In the Guardian's science weekly podcast, Dr Dartnell says: "Astrobiology is going out there and being proactive, and searching and exploring the solar system - building probes to go to Mars for example to test the sands that we scoop up. One of the first things we need to think about is what is life in the first place? We're looking for molecules like DNA and proteins."

Meanwhile NASA this week has released new images of the surface of Mars, taken from its reconnaisance orbiter - one step closer, perhaps, to finding out if life on other planets is really fact, or just science fiction.