Came across an interesting article over on the IEEE website which excited me on several levels. Firstly it is about the newly confirmed U.S. Secretary of Energy, Steven Chu – who is less a politician and more a very good scientist. Such a rarity to have a scientist holding such an important job in US politics!
However, the article is talking about a technique he has developed – based on an atomic interferometer, which relies on the weird quantum world to measure the effect of gravity wherever the detector is based. Gravity, being a consequence (or cause?) of mass is therefore variable depending on how much heavy mass you have around you. Stand on loosely tilled soil, and gravity will be lower than if you are standing on solid rock.
Hence, by measuring gravity, you can map the world – very useful for working out what is deep under the soil, such as oil – but also as a potential future replacement for navigation devices.
I just happen to think that no matter how useful navigating by GPS satellite is – navigating by gravity fluctuations in the ground measured by a quantum atomic interferometer just ticks the awesome box in so many ways.
Incidentally – thanks to the way time is affected by gravity – the clocks in GPS satellites run at a slower speed to the clocks on the planets surface, and need regular resetting by a signal from the ground to keep them in sync with us humans.
Which I think is rather amazing in its own right.