Every now and then a space rock hits the world's media – sometimes almost literally. Threatening asteroids that zoom past the Earth, fireballs in the sky seen by hundreds of people and mysterious craters which may have been caused by impacting meteorites; all make ESA's planned mission Don Quijote look increasingly timely.

The uncertainty surrounding whether a meteorite impacted in South America recently highlights the need to know more about these pieces of natural space debris and their trajectories. ESA has always been interested in such endeavours and conducted a number of studies into how it might best help.

Researchers have discovered that even the gruesome and brutal lifestyle of the Evarcha culicivora, a blood gorging jumping spider indigenous to East Africa, can’t help but be tempted by that ‘big is beautiful’ mantra no matter what the costs.

A study recently published in Ethology found that despite the inherent risk of sexual cannibalism, virgin females were attracted to bigger males when losing their virginity before opting for the safer smaller male as a longer term mate choice.

Everyone knows how a bicycle works - or so we think. But for 150 years why a moving bicycle can, all by itself, be so stable has been something of a mystery.

"Bicycle manufacturers have never been able to say precisely how a bicycle works," explains Dr Arend Schwab of the Faculty of Mechanical, Maritime and Materials Engineering (3mE). "They have always had to refine their designs purely through experimentation. In our model, they can enter into the computer all of the various factors that influence the stability and handling of their bicycle.

The majority of patients who undergo male to female sex-change surgery are happy with the results, despite the fact that complications are common, according to a study of over 200 patients in the September issue of the urology journal BJU International.

A research team from the Departments of Urology and Psychiatry at University Hospitals of Leicester NHS Trust, UK, explored the initial experiences of 222 patients who had undergone surgery and 70 who took part in detailed follow-ups.

They found that 88 per cent of patients were happy with their surgery at their first post-operative clinic visit, seven per cent were unhappy and five per cent made no comment.

"We've never seen anything quite like it," says solar physicist Lika Guhathakurta from NASA headquarters.

Last week she sat in an audience of nearly two hundred colleagues at the "Living with a Star" workshop in Boulder, Colorado, and watched in amazement as Saku Tsuneta of Japan played a movie of sunspot 10926 breaking through the turbulent surface of the sun. Before their very eyes an object as big as a planet materialized, and no one was prepared for the form it took.

"It looks like a prehistoric trilobite," said Marc De Rosa, a scientist from Lockheed Martin's Solar and Astrophysics Laboratory in Palo Alto, Calif.

Researchers in the MIT Media Lab's Biomechatronics Group have created an exoskelton device to lighten the burden for soldiers by transferring that weight directly to the ground, effectively taking a load off the back of the person wearing the device.

In the September issue of the International Journal of Humanoid Robotics, the researchers report that their prototype can successfully take on 80 percent of an 80-pound load carried on a person's back, but there's one catch: The current model impedes the natural walking gait of the person wearing it.

"You can definitely tell it's affecting your gait," said Conor Walsh, a graduate student who worked on the project, but "you do feel it taking the load off and you definitely feel less stress on your upper body."