Like the rings or Saturn, or the hypnotizing blue quality of Neptune, the Great Red Spot of Jupiter is, arguably, the planets most iconic feature. Easily distinguishable amongst the swirls and atmospheric striations that freckle the gas giant, the Great Red Spot is almost synonymous with its host, but this won’t be the case forever. The trademark phenomenon is shrinking, but fortunately for star gazers, its putting up a fight.
Recently, in a series of annual portrait of the outer planets, NASA has used the Hubble Space Telescope to create new maps of the planet, which have revealed a plethora of new information regarding Jupiter. The maps have shown astronomers that the Great Red Spot, which in fact is a storm about twice the diameter of Earth that has been raging on Jupiter since at least 400 years ago (when it was first observed by humans), is shrinking at a speed which is slowly diminishing.
This is on contrast to the previous trend in which the rate of decrease in size was raising exponentially. Although the shrinking trend has not completely reversed, comparisons in images of the planet have shown that the rate at which it has shrunk is moving at a smaller pace, with new images placing the size at 240 kilometers (150 miles) smaller than in 2014.
Size, however, isn’t the only thing NASA observed from the images of the Hubble Space Telescope. An uncommon delicate filament that spans the length of the spot can be seen, bending under the will of 540 kilometer (335 mile) an hour winds. Rare wave structures, the likes of which haven’t been seen by the scientific community in 40 years have also been identified. Due to a massive map compiled of images of Jupiter taken over a span of 10 hours, scientists have been able to closely study the atmosphere of the gas giant, with observations including wind speed, atmospheric events, and changes in the planets outer layer.
This has turned researchers’ attention to an area just north of Jupiter’s equator, where a structure of waves has been identified that was only ever been seen once before in the history of planetary study. During the 1977 Voyager 2 mission, similar wave structures were observed, albeit barley, and the structure’s nearly 40 year absence had led to the now obsolete opinion that they were merely a fluke.
Currently, the area in which this rare feature exists is inhabited with cyclones and anticyclones. These conditions can be likened to areas on Earth where cyclones are just starting to form, and similar structure known as baroclinic waves form. These features must form beneath the clouds that we observe on the outer atmosphere Jupiter, closer to the surface researchers’ say. They then become visible once they move up and into the cloud deck.
The new maps that aided in these observations and subsequent studies can be attributed to the outer Planet Atmospheres Legacy (OPAL), which uses the Hubble Space Telescope to study the outer planets every year. Neptune and Uranus have already been looked at, with Saturn up next. Every image of these planets will be compiled into maps similar to the ones used with Jupiter, which will be filed into public archive in the near future. Scientists’ hope to use these maps to not only gain an understanding of the atmospheres of these planets, but also to aid in the understanding of that of Earth, and planets beyond our solar system.