Gee fizz! Earth is surrounded by more bubbles than an Aero chocolate bar, space scientists have discovered. They were discovered by a fleet of European satellites that bump into them during their orbits.
The four-spacecraft flotilla called Cluster have encountered thousands of bubbles of superheated gas as they pass over the sunlit, daytime side of the Earth.
Their discovery, confirmed by a joint European satellite mission with China called Double Star, will help scientists understand how a stream of particles from the sun called the solar wind interacts with the Earth’s magnetic field.
The bubbles, found at a distance of 50,000 to 75,000 miles above the Earth, are known as density holes. They are regions of space where the density of gas suddenly becomes ten times lower but the temperature of the remaining gas leaps from 100,000 C to ten million C.
Researcher George Parks, of the University of California, Berkeley, said he thought he was seeing instrumentation glitches when Cluster first flew through the bubbles. Then he saw that the data was recorded by all four craft in the flotilla and he realised the effect was real.
Parks says that during every orbit, the spacecraft fly through 20 to 40 bubbles which expand to about 600 miles in size (1,000km) and probably last about ten seconds before they burst.
The ESA artist’s image shows the Earth’s magnetosphere (in blue) embedded in the flow of the solar wind coming from the left.