Image for Zone of repugnance

Zone of repugnance

Duration: 04:28

The fastest living thing on the planet can be found in the most unlikely places. Saprobes, found in horse manure, grow quickly. The pilobolus can do 0-20 in 2 millionths of a second and pull 20,000 G. Astronauts on a space shuttle have to cope without about 4G, get anything past about 5G and people start passing out. Watching the spores on the top of the fungus, at normal speed they seem to just vanish, it's so fast, it's invisible to our eyes. With the development of ultra high speed cameras, it's only recently we have been able to see these horse poo superstars. Slowed down 10,000 times we can see the spores hurtling through the air, so fast it's like us being catapulted to 100 times the speed of sound. All of which begs the question: why? Why does a fungus that lives in poo need to be the speediest thing on the planet? Well it's all to do with the zone of repugnance. For the fungal family to survive, their spores need to get eaten by another grass eater. To do that, they need to get away from the area around the poo, known as the zone of repugnance, and that means clearing overtwo metres. The problem is that the air becomes too thick - the smaller you are, relatively speaking, the thicker the air becomes. The only solution therefore is to go so fast you can power through the air to get to the fresh grass beyond. Underneath each spore, a tiny bubble of liquid pressure builds up, until finally it bursts, launching the spore at its tip more than two metres away.

Available since: Fri 14 May 2010

Credits

Presenter
Richard Hammond
Director
Gavin Maxwell
Producer
Gavin Maxwell
Producer
Simon Finch
Executive Producer
Anne Laking
Executive Producer
Gary Hunter
Presenter
Richard Hammond
Director
Gavin Maxwell
Producer
Gavin Maxwell
Producer
Simon Finch
Executive Producer
Anne Laking
Executive Producer
Gary Hunter
Presenter
Richard Hammond
Director
Gavin Maxwell
Producer
Gavin Maxwell
Producer
Simon Finch
Executive Producer
Anne Laking
Executive Producer
Gary Hunter

This clip is from

Richard Hammond's Invisible Worlds Speed Limits

1/3 Using high-speed cameras, Richard Hammond goes beyond the limits of the naked eye.

First broadcast: 16 Mar 2010

Image for Speed Limits Not currently available on BBC iPlayer

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