Then and Now: First Jupiter Photo vs James Webb’s Latest Shot

Astronomer Jasmine Singh has shared a fascinating comparison of the earliest photograph ever taken of Jupiter and the most recent James Webb Space Telescope (JWST) image of the planet.

The earliest photo of Jupiter was taken in 1879 by Irish astronomer Agnes Mary Clerke who published it in her book A Popular History of Astronomy During the Nineteenth Century.

The recent JWST photocaptured on July 27, 2022, is a composite image and has such remarkable clarity that Jupiter’s auroras can be seen dancing above both of its poles.

The side-by-side comparison underlines just how far astrophotography has improved in the last 142 years.

The 19th-century photo is grainy, but it is still obvious that it is Jupiter thanks to the planet’s distinctive banding caused by differences in the chemical composition and temperature of the atmospheric gas.

The Great Red Spot

Another unique feature on Jupiter is its Great Red Spota persistent high-pressure region that produces anticyclonic storms that are the largest in the Solar System.

This mark can be seen on Clerke’s 1879 photo, but the image is upside down making it appear as if it is in the northern hemisphere, not the southern.

1879

Another fascinating insight is how much larger the Great Red Spot appears in 1879 and this has been backed up by subsequent studies.

At one time the monster storm was so large that three Earths would have fitted inside it. But it is now estimated that only one Earth could fit in the Great Red Spot. Scientists disagree on the causes.

Skywatchers in 1879 noticed prominent swirling storms from the Great Red Spot, which is perhaps what piqued Clerke’s interest.

James Webb Photo

The 2022 JWST photo of Jupiter, which is a composite of several images, has a distinct blue tinge, differing from the usual reddish impression of Jupiter.

JWST

The photo came from the telescope’s NIRCam which used three of its specialized infrared filters. Infrared capture is used to reveal the planet’s details but it is not visible to the human eye.

NASA teamed up with citizen scientist Judy Schmidt to translate the Webb data into visible images. Longer wavelengths of light appear redder while the shorter ones appear bluer.

“The auroras shine in a filter that is mapped to redder colors, which also highlights light reflected from lower clouds and upper hazes. A different filter, mapped to yellows and greens, shows hazes swirling around the northern and southern poles, ”the European Space Agency explains.

“A third filter, mapped to blues, showcases light that is reflected from a deeper main cloud. The Great Red Spot, a famous storm so big it could swallow Earth, appears white in these views, as do other clouds, because they are reflecting a lot of sunlight. “


Image Credits: JWST photo is by NASA, ESA, and Jupiter ERS Team, with image processing by Judy Schmidt. 1879 photo by Agnes Mary Clerke