The Great Red Spot on Jupiter is the planet's most defining feature -- and humanity has been watching it for a while. There is speculation that a mention of Jupiter's "permanent spot" from writings in the 1600s are a reference to the raging storm. And in the 1800s, observations of the spot put its measurement at about 25,476 miles wide -- which would be big enough to engulf three Earths.
But more recent observations have shown that the Great Red Spot is shrinking. When NASA's Voyager passed by in 1979 and 1980, it put the spot at a width of about 14,500 miles. And now, a new image from the Hubble Space Telescope places the raging anticyclone at an even smaller size.
"Recent Hubble Space Telescope observations confirm that the spot is now just under 16,500 kilometres (about 10,252 miles) across, the smallest diameter we've ever measured," Amy Simon of NASA's Goddard Space Flight Center said in a statement.
Not only is the spot shrinking, but it's doing so faster than ever, NASA says. Yet the cause is largely unknown.
"In our new observations it is apparent that very small eddies are feeding into the storm," said Simon, who plans further studies of these eddies. "We hypothesized that these may be responsible for the accelerated change by altering the internal dynamics of the Great Red Spot."
Winds at the edge of the spot, which is a storm that's been raging for hundreds of years, spin in a counterclockwise direction and are estimated to reach 450 mph at the storm's edge. Considering that even at its current size, the spot could still swallow our planet whole, it's a good thing that Jupiter is over 350 million miles away.