computer hard-disk readers

[TerraFrost]

A while ago, three physicists won the Nobel prize for work that was ultimately used to make hard drives. Although it isn't exactly new technology, here's a neat analogy:

"A computer hard-disk reader that uses a GMR sensor is equivalent to a jet flying at a speed of 30,000 kmph, at a height of just one metre above the ground, and yet being able to see and catalogue every single blade of grass it passes over."

source

[Drazo]

A bit off topic but I think hard drives that take longer to stop spinning is a sign of prolonged life because obviously, aside from more platters, there's less friction around any moving parts thus less wear. I love sound of my 200 GB hard drive (my second one) when it turns off it sounds like a jet engine turning off....and takes forever to stop spinning.

[TerraFrost]

The Lunar Laser Ranging experiment doesn't really have anything to do with Giant magnetoresistance, but the analogy given on wikipedia.org reminds me of the analogy given in this topics first post:

At the Moon's surface, the beam is only about 6.5 kilometers (four miles) wide[5] and scientists liken the task of aiming the beam to using a rifle to hit a moving dime 3 kilometers (two miles) away. The reflected light is too weak to be seen with the human eye, but under good conditions, one photon of the 10^17 photos aimed at the reflected will be received back on Earth every few seconds (they can be identified as originating from the laser because the laser is highly monochromatic). This is one of the most precise distance measurements ever made, and is equivalent in accuracy to determining the distance between Los Angeles and New York to one hundredth of an inch.[3][6] As of 2002 work is progressing on increasing the accuracy of the Earth-Moon measurements to near millimeter accuracy, though the performance of the reflectors continues to degrade with age.

[TerraFrost]

At the time, the gyroscopes were the most nearly spherical objects ever made. Approximately the size of ping pong balls, they are perfectly round to within forty atoms (less than 10 nm). If one of these spheres were scaled to the size of the earth, the tallest mountains and deepest ocean trench would measure only 2.4 m (8 ft) high.

source: http://en.wikipedia.org/wiki/Gravity_Probe_B