We sometimes find that objects in our collections suddenly become newsworthy because of events beyond the Museum. This beautiful, but small and unassuming, object on display in Cosmos & Culture is now one of them.
It’s a prototype gyroscope from the Gravity Probe B experiment, which has been testing predictions made by Einstein’s general theory of relativity: that a massive body such as the Earth should warp and twist the space-time around it.
Four spheres like this one – among the most perfect ever made – were set spinning on a spacecraft precisely pointed towards a guide star. Scientists spent several years ploughing through data to see if the angle of the spheres’ spin was altered by the warp and twist, and yesterday NASA announced the results. They’re just as Einstein predicted.
We acquired the gyroscope back in 2005, while the spacecraft was busy gathering data, and I was lucky enough to meet chief scientist Francis Everitt.
At the time he was non-commital about what the experiment might reveal: ‘There’s many reasons for thinking that as magnificent as the advance General Relativity gives, it’s not quite the final answer. Whether, for example, in our experiment or not one will find anything different from Einstein, I’ve no wish to make any prediction about. Our job is to do the experiment. But physics advances, science advances, by measuring things’.
The results are a huge vindication for the Gravity Probe B project – it was in the planning for over 40 years and the mission faced cancellation several times. But, as Everitt says, we still may not have the final answer.
General relativity is so complex that there are many other predictions of the theory which are yet to be confirmed, and other scientists are busy making their own measurements. Some of the experiments haven’t even started yet. This is a prototype part for Advanced LIGO, a ground-based experiment due to be completed in 2015.
Here‘s how it works … and here‘s how we put it together for exhibition display (cue lots of head-scratching from our Workshops team). Some time after 2015, might this object also be hitting the headlines?