NASA has been monitoring the size of the Great Red Spot on Jupiter using telescopic observations and spacecraft missions. The initial observations of the Great Red Spot date back to the 17th century, and NASA has been continuously studying it since the 1970s.
Here's an overview of the methods used to determine the shrinking of the Great Red Spot:
Telescopic Observations: Astronomers have been using ground-based telescopes, such as the Hubble Space Telescope and large observatories, to observe and track the Great Red Spot over the years. By measuring the size and shape of the spot in images captured by these telescopes, scientists can compare the data and track any changes in its dimensions. By observing the spot repeatedly and over extended periods, they have been able to determine that it has been decreasing in size.
Spacecraft Missions: NASA's spacecraft missions, such as Voyager and Galileo, have provided close-up observations of Jupiter and the Great Red Spot. These missions have utilized instruments like cameras, spectrometers, and other imaging tools to capture detailed images and gather data about the planet's atmosphere. By comparing the images and measurements from different spacecraft flybys, scientists have been able to assess the changes in the size and structure of the Great Red Spot.
Data Analysis: Scientists analyze the collected data from telescopic observations and spacecraft missions to track the changes in the size and characteristics of the Great Red Spot. They use image-processing techniques, computer models, and advanced analysis methods to measure the dimensions of the spot accurately. By comparing data from different time periods, they can establish trends and deduce that the Great Red Spot has been shrinking.
Based on these observations and analyses, NASA scientists have determined that the Great Red Spot has been gradually decreasing in size. However, it's worth noting that the rate of shrinking can vary over time, and the spot may undergo fluctuations in its size and shape. Continued monitoring and analysis will help to refine our understanding of this intriguing feature on Jupiter.