Feeds

Boffins explain greatest ever free kick

Roberto Carlos and his amazing exponential spiral

Providing a secure and efficient Helpdesk

Scientists have agreeably concluded that Roberto Carlos's 1997 free kick against France - a seemingly impossible blast into the back of the net from 115ft - was not the fluke some have claimed.

While hapless French keeper Fabien Barthez might have taken solace from the thought that perhaps a gust of wind had accounted for the ball's improbable trajectory, the fact is that it was all down to Carlos and his amazing exponential spiral.

That's according to a team of researchers from the École Polytechnique in Palaiseau, near Paris, who demonstrated that while the ball's trajectory initially conformed to the Magnus effect, which gives a spinning sphere a curved path, the distance of this particular free kick added a surprise ending.

By firing plastic balls into a tank of water, the boffins showed that if a football's spin speed remains constant, "its trajectory follows an exponential spiral", with the bend "surprisingly" increasing as drag slows the ball down.

In the final phase, where both velocity and spin decrease, the ball tends to follow a straight line before hitting the back of the net.

The distance here is critical. Researchers Christophe Clanet and David Quéré explained: "When shot from a large enough distance, and with enough power to keep an appreciable velocity as approaching the goal, the ball can have an unexpected trajectory.

"Carlos' kick started with a classical circular trajectory but suddenly bent in a spectacular way and came back to the goal, although it looked out of the target a small moment earlier.

"People often noticed that Carlos' free kick had been shot from a remarkably long distance, we show in our paper that this is not a coincidence, but a necessary condition for generating a spiral trajectory."

The full explanation of the Roberto Carlos exponential spiral can be found here in the latest edition of New Journal of Physics. ®

Internet Security Threat Report 2014

More from The Register

next story
MARS NEEDS WOMEN, claims NASA pseudo 'naut: They eat less
'Some might find this idea offensive' boffin admits
LOHAN crash lands on CNN
Overflies Die Welt en route to lively US news vid
Comet Siding Spring revealed as flying molehill
Hiding from this space pimple isn't going to do humanity's reputation any good
Experts brand LOHAN's squeaky-clean box
Phytosanitary treatment renders Vulture 2 crate fit for export
No sail: NASA spikes Sunjammer
'Solar sail' demonstrator project binned
Carry On Cosmonaut: Willful Child is a poor taste Star Trek parody
Cringeworthy, crude and crass jokes abound in Steven Erikson’s sci-fi debut
Origins of SEXUAL INTERCOURSE fished out of SCOTTISH LAKE
Fossil find proves it first happened 385 million years ago
Human spacecraft dodge COMET CHUNKS pelting off Mars
Odyssey orbiter yet to report, though - comet's trailing trash poses new threat
prev story

Whitepapers

Forging a new future with identity relationship management
Learn about ForgeRock's next generation IRM platform and how it is designed to empower CEOS's and enterprises to engage with consumers.
Why and how to choose the right cloud vendor
The benefits of cloud-based storage in your processes. Eliminate onsite, disk-based backup and archiving in favor of cloud-based data protection.
Three 1TB solid state scorchers up for grabs
Big SSDs can be expensive but think big and think free because you could be the lucky winner of one of three 1TB Samsung SSD 840 EVO drives that we’re giving away worth over £300 apiece.
Reg Reader Research: SaaS based Email and Office Productivity Tools
Read this Reg reader report which provides advice and guidance for SMBs towards the use of SaaS based email and Office productivity tools.
Security for virtualized datacentres
Legacy security solutions are inefficient due to the architectural differences between physical and virtual environments.