Scientists identify polar cyclone on mysterious Uranus

WASHINGTON — It is a world wrapped in mystery — the seventh planet from the sun, Uranus, seen up close just once nearly four decades ago by a passing NASA probe and still warily guarding its secrets.

But new observations from a telescope located in New Mexico are providing a fuller understanding of its atmosphere, including the detection of a polar cyclone whose centre measures a quarter of Earth’s diameter, swirling near its north pole.

Scientists were able to gaze more deeply into the atmosphere of Uranus — a planet classified as an ice giant, like its planetary neighbour Neptune — than ever before. The findings painted a picture of a planet more dynamic than previously known.

“While the general makeup of its atmosphere and interior are similar to Neptune — as far as we know — Uranus has some pretty unique features,” said planetary scientist Alex Akins of NASA’S Jet Propulsion Laboratory in California, lead author of the research published in the journal Geophysical Research Letters. “It spins on its side. And even then, its magnetic field is still misaligned with its rotational axis. The atmospheric circulation and internal heat release appear weaker than Neptune, but there are still a range of dynamical features and storms that have been observed.”

Uranus, blue-green in colour due to the methane contained in an atmosphere comprised mostly of hydrogen and helium, is the third-largest planet in our solar system. It has a diameter of about 50,700 kilometres and is big enough to fit 63 Earths inside it.

Uranus orbits the sun at a distance of about 2.9 billion kilometres, almost 20 times further than Earth does. One orbit lasts 84 years.