Astronomers have discovered a second Great Cold Spot on the surface of Jupiter. The biggest planet Jupiter is known for its Great Red Spot, scientists attribute this other spot caused by the planet's vibrant auroras.
Dubbed as the ‘Great Cold Spot’ has been observed as localised dark spot, up to 24,000 km in longitude and 12,000 km in latitude, in the gas giant's thin high-altitude thermosphere, that is around 200K (Kelvin) cooler than the surrounding atmosphere, which can range in temperature between 700K (426ºC) and 1000K (726ºC).
According to the lead author of the study, Dr Tom Stallard, Associate Professor in Planetary Astronomy, “This is the first time any weather feature in Jupiter's upper atmosphere has been observed away from the planet's bright aurorae.
“The Great Cold Spot is much more volatile than the slowly changing Great Red Spot, changing dramatically in shape and size over only a few days and weeks, but it has re-appeared for as long as we have data to search for it, for over 15 years. That suggests that it continually reforms itself, and as a result it might be as old as the aurorae that form it -- perhaps many thousands of years old.”
What caused the Cold Spot?
It is thought to be caused by the effects of the magnetic field of the planet. Using the CRIRES instrument on the Very Large Telescope (VLT) astronomers observed spectral emissions of H3+, an ion of hydrogen present in large amounts in Jupiter's atmosphere, which allowed them to help map the mean temperature and density of the planet's atmosphere.
What makes it different from the Red Spot is the fact that Great Cold Spot is much more volatile than the slowly changing Great Red Spot.
Scientists combined over 13,000 images taken by NASA's InfraRed Telescope Facility, they revealed the presence of the Great Cold Spot as an area of darkness amongst the hot environment of Jupiter's upper atmosphere.