The James Webb Space Telescope observed Saturn for the first time, completing a family portrait of the solar system’s ringed planets nearly a year after the mission’s first stunning image.
Webb’s near-infrared camera took the picture of Saturn on June 25. Scientists added an orange color to the monochrome photo to produce the image released Friday.
The image shows Saturn’s iconic icy rings shining around the gas giant’s disk, which appears much darker in the near-infrared due to the absorption of sunlight by methane particles floating high in the planet’s atmosphere.
Webb aimed his 21.3-foot (6.5 meters) gold-plated mirror at Saturn as part of an observing program to test the telescope’s ability to detect faint moons. The observations include several deep exposures of Saturn that astronomers are still analyzing to examine the planet’s fainter rings and search for undiscovered moons.
There are 146 known moons orbiting Saturn, ranging in size from larger than the planet Mercury to the size of a sports arena, more than any other planet in the solar system, according to NASA.
“Any newly discovered moons could help scientists gain a more complete picture of Saturn’s current system, as well as its past,” NASA said in a blog post released with the new Saturn image.
Three of Saturn’s moons appear on the left side of the planet according to Webb: Dione, Enceladus and Tethys are visible as points of light. Each is about the size of a major US state.
Recent observations of Enceladus using Webb’s near-infrared spectrograph instrument revealed a jet of water vapor extending more than 10,000 kilometers into space, 20 times the diameter of the moon. Scientists say Enceladus is one of the most promising locations in the solar system to search for signs of life, as it harbors a water ocean beneath a global ice sheet.
NASA’s Cassini orbiter flew past Enceladus many times before its mission ended in 2017. Cassini spotted similar plumes of water erupting through cracks in Enceladus’ ice sheet and flew through the jets to sample the particles emanating from the moon’s deep ocean.
The Cassini spacecraft captured higher-resolution images of Saturn than Webb, but now that Cassini’s mission is over, Webb is the main tool scientists will use to continue studying Enceladus and Saturn for at least the next decade.
There is currently no mission scheduled to visit Enceladus. NASA’s robotic Dragonfly mission is scheduled to launch toward Saturn in 2027, but will focus on exploring Titan, Saturn’s largest moon.
Webb’s first scientific images were released nearly a year ago and show the promise of the $10 billion mission to look deeper into the Universe than ever before. Observations within the solar system are just one part of Webb’s science portfolio, in addition to scientific topics such as studying the formation of the first galaxies after the Big Bang and searching for planets around other stars that may contain the ingredients for life.
Webb science teams have previously released spectacular images of the solar system’s other ringed planets – Jupiter, Neptune and Uranus – along with the first observations of Mars.
Webb is stationed about a million miles from Earth and cannot observe the moon, Mercury or Venus because they are too bright or too close to the sun.
