Scientists believe they are on the verge of measuring gravitational waves, one of the most elusive phenomena in the universe, for the first time. Albert Einstein predicted the existence of these waves as part of his general theory of relativity. He argued that when a mass accelerates, it causes the fabric of spacetime around it to stretch and squeeze. The waves have remained elusive to scientists for a simple reason: gravity is such a weak force that it produces extremely tiny waves, and no instrument has usually been sensitive enough to detect them. But that limitation may soon be over. Yesterday, scientists at Hanford in the US kicked off an experiment with a $350m (£200m) machine called Ligo which they are confident will bring the first evidence for the existence of Einstein's elusive waves. Next month, Ligo will be joined by the Geo 600 detector in Hanover, which cost €7m (£4.7m) and is being run by scientists from Glasgow, Cardiff, Birmingham and Hanover universities. The first attempt to detect the waves was made in the 1960s by University of Maryland physicist Joseph Weber. His experiment involved suspending a 1 ton aluminium bar in a vacuum and waiting to see if any passing gravity waves caused it to expand and contract. Unfortunately, he got too many false alarms and his detections were discredited. Modern detectors use lasers to measure the change in distance caused by gravity waves between two test masses. The Ligo and Geo 600 systems are so sensitive they can detect changes in distance which are less than 1/3000th of the width of a proton - or less than a thousand billion billionths of a metre. Scientists know any true observation of gravity waves will need simultaneous recordings in all the detectors.
View: Full Article | Source: The Guardian
It takes the entire Mass of the earth to make one G of Gravity. So making a Gravity Machine is a bit in the Future yet. Some have claimed to block gravity's influence with a strong ElectroMagnetic Field. But there is not enough power to counter the Earth's pull on anything of size.
