Astronomy Picture of the Day

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

August 6, 1999 Hubble Tracks Jupiter's Great Red Spot Credit: Amy Simon et al. & the Hubble Heritage Team (AURA/ STScI/ NASA)

Explanation: It is a hurricane twice the size of the Earth. It has been raging at least as long as telescopes could see it, and shows no signs of slowing. It is Jupiter's Great Red Spot, the largest swirling storm system in the Solar System. Like most astronomical phenomena, the Great Red Spot was neither predicted nor immediately understood after its discovery. Still today, details of how and why the Great Red Spot changes its shape, size, and colour remain mysterious. A better understanding of the weather on Jupiter may help contribute to the better understanding of weather here on Earth. In the pictures on the left, the Hubble Space Telescope has captured Jupiter's Great Red Spot in various states over the past several years.