We have all seen and heard of it. Jupiter's Great Red Spot is one of the planets primary distinguishing features. It's surprising to learn that, although its terrifying, the Great Red Spot is simply a massive vortex of swirling gases.
How massive? It's about 20,000 km in length and 14,000 km wide (about 8,000 by 12,400 miles). Put simply, it's large enough to engulf somewhere between 2-3 entire Earths. Now that's big. While size does matter, it's not the only significant feature of this monster. The howling winds, loud thunder, and blinding lighting only add to its reputation.
So what exactly keeps the storm alive? Similar to Earth, the system is fueled by two opposing jet streams. Between the two streams, "pockets" of air can get trapped and start swirling. The Great Red Spot is an example of swirling that's simply out of control. Additionally, storms on Earth die out quickly once they make landfall. Since Jupiter is a completely gaseous planet, land isn't an impeding factor.
However, it's possible that this giant may not last forever. In the past 100 years, the storm has nearly halved in size, and it continues to shrink. We still do not understand much about the Great Red Spot, but astronomers hope that future probes can shed some more light on this beast.