Do aurorae occur on other planets and moons?
Aurorae do not occur on our moon, but they do occur on other planets like Mars and the gas giants.
This week's question comes from Jane Sanders in Mississauga, Ont. She asks:
Is there anything like the aurora borealis on Mars or the moon?
Emily McCullough, an atmospheric lidar scientist at Dalhousie University in Halifax, says scientists expect to see aurorae on other planets that have two key ingredients; an atmosphere and a magnetic field.
Aurorae occur when charged particles from the sun are sped up by Earth's magnetic field and excite other atoms in the atmosphere. The atoms then release that energy in the form of colourful light, which we see as northern and southern lights.
Since the moon has no magnetic field and only a very thin atmosphere, there are no aurorae on the moon.
Mars is a bit different. It does have an atmosphere, but does not have a magnetic field, however a type of aurora has been observed on Mars. There are patches of magnetic rocks left over from when Mars did have a magnetic field that induce weak ultraviolet aurorae, so they occur in patches all over Mars instead of at the poles like they do on Earth.
Beyond Mars the gas giants also have atmospheres and magnetic fields, and satellites have recorded aurorea on Jupiter, Saturn, Uranus and possibly Neptune.