Saturn's 'spoke season' has started, and the Hubble Space Telescope captured it

Summer is almost over on planet Earth as we head towards the equinox later next month. Key points: Saturn gets strange "spokes" in its rings that only appear when the planet is near equinox The Hubble Space Telescope has captured images that herald the beginning of "spoke season"' Scientists believe the spokes may be caused by the planet's magnetic field, but it's a mystery why they only appear at equinox The Hubble Space Telescope has captured the first signs of "spoke season", the appearance of mysterious spokes — or in this case blobs — in Saturn's rings. "I was pretty excited when we saw them," said Amy Simon, an astronomer at NASA's Goddard Space Flight Center and head of Hubble's Outer Planet Atmospheres Legacy Program. Observations of the planet over the years — by the Cassini spacecraft and Hubble — indicate spoke season tends to start pretty much on time around two years out from equinox, Dr Simon said. "Unfortunately one nice long season of the spokes from Cassini is not really enough to tell us exactly what's going on here," Dr Simon said.