What is the Great Dark Spot of Neptune?
When we think about our solar system, we rarely reach to the point of wondering about Neptune and Pluto. Most often, our thoughts stop at the gigantic Jupiter or the magnificent rings of Saturn, isn’t it? Well, Neptune has some cool facts about it too that we don’t know!
Giant storms produce Dark Spots
For starters, the weather on Neptune, the eighth planet from the Sun, is one of the weirdest in our solar system. Wind flows at a speed of 1,100 miles per hour there i.e., 1.5x the speed of sound! Thanks to such crazy weather, a giant storm, that appears like a massive dark spot about 7402 kilometres wide, has been identified on this planet! This storm was identified by the Hubble Space Telescope in 2018.
In fact, the spot is so big, it is comparable to our Earth in size! This means Neptune has a dark spot on its surface the size of Earth! The spot is the place where the wind speed is maximum, possibly resulting in the tell-tale appearance of an immense dark oval shape. Imagine being trapped in such a storm. There is no way you could get out!
How was the spot discovered?
The story of how the dark spot got detected is quite interesting. The year was 1989 when a NASA spaceship called Voyager 2 had passed by Neptune. It took plenty of images of the planet and two spots were observed in these images. However, in 1991, when the Hubble Space Telescope took images of Neptune, these spots were nowhere to be found. What happened to the spots then? The answer lies in the lifespan of the dark spot! The average life span of such storms on Neptune is two to five years. It depends on how big or small the storm is. So, when scientists were able to observe Neptune via the Hubble telescope, the storm was probably over.
There is another dark spot too!
Neptune does not have only one massive dark spot. There is another one also! Scientists believe this must have been broken off from the main storm. However, this is not the first time dark spots on this planet have behaved so strangely. The Great Dark Spot of Neptune can move! For instance, in 1989, when Voyager 2 spacecraft passed Neptune, it observed two storms. The more prominent spot moved to the south first and then changed its direction to the north. It might be due to the varying wind speeds and changes in the direction of the winds, moving the storm from one place to another.
Even Jupiter has dark spots
Yes, that’s right! The Great Dark Spot of Jupiter, the best-known storm in our solar system, may shrink sometimes, but has been ongoing for at least a hundred years! The Hubble telescope uncovered two dark spots in 2018. The Giant spot is wider than our Atlantic Ocean in size (4,600 miles) while the smaller spot is 3,900 miles wide! Talk about gigantic things of the universe!