But since its first observation in the 1600s, Jupiter's Great Red Spot has slowly made its way to becoming more like the Okay Red Spot, or perhaps more charitably, the Once-Great Red Spot. Measurements made in the 1800's put the storm at 41,000km across—where it could comfortably swallow three Earths. But by the time the Voyager probes passed by in 1979 and 1980, the storm had shrunk to 23,335km. Now. thanks to the Hubble Telescope, scientists have been able to monitor the shrinking storm better than ever, as shown in the image below.