Webb’s Shows New Images Close to Home: Neptune’s Rings and a Bright Mars

An image of Neptune captured by the Webb telescope’s Near-Infrared Camera.  NASA, ESA, CSA, STScI

From its perch one million miles from Earth, the James Webb Space Telescopehas peered deep into our solar system to capture images of Neptune. These new views show seven of the distant planet’s 14 known moons, but it’s the rings that really take the spotlight.

The pictures, taken in July and released Wednesday, provide the clearest and most detailed look at Neptune’s rings since NASA’s Voyager 2 spacecraft flew by the planet in 1989, according to Marcia Dunn of the Associated Press (AP).

This image labels seven of Neptune’s 14 known moons.  NASA, ESA, CSA, STScI

In a zoomed-out picture, an object that looks like a bright star shines above Neptune. In reality, it’s no star—it’s Neptune’s largest moon, Triton, which is covered by a frozen layer of nitrogen, according to Space.com. Triton is larger than Pluto and appears so bright because its ice layer is reflective, per the AFP.

A zoomed out picture from Webb shows distant galaxies in the background.  NASA, ESA, CSA, STScI

Neptune, the farthest planet from the sun, was discovered in 1846. Its small, rocky core is surrounded by a hot, dense fluid of water, methane and ammonia. In previous images of Neptune taken by the Hubble Telescope, the planet has a Smurf-like blue hue, which is caused by methane in its atmosphere, according to Space.com’s Robert Lea.

To Voyager 2 and the Hubble Telescope, Neptune looked blue due to methane gas in its atmosphere. Webb used its Near-Infrared Camera to observe Neptune, so the planet now appears more grey.  NASA, ESA, CSA, STScI

To Webb’s infrared gaze, though, Neptune doesn’t appear so blue—since methane absorbs infrared light, the areas of the planet not covered by bright, high-altitude clouds seem dark to the high-tech telescope, per Space.com.

A mosaic of the Mars globe compiled from images obtained by the Viking Orbiter. (NASA/JPL-Caltech)

Webb is mostly studying the early universe, looking far beyond our solar system for glimpses of the formation of the first stars and galaxies, per the AP. But it’s also telling us more about planets closer to home. Space agencies released images of Mars earlier this week and unveiled the telescope’s view of Jupiter in August.

The resulting images show Mars in a very different light – infrared, in fact – giving us information about the red planet that we would not be able to see with our naked eyes.

It is quite difficult for JWST to image something close to home. It is the most powerful telescope ever launched into space, designed to be sensitive enough to detect the extremely faint light from the most distant objects in the Universe. Compared to these, Mars burns like a furnace.

To avoid the oversaturation that would normally occur from this brightness, the scientists who took the observations and processed the data had to use techniques to compensate. The timing of the exposures was extremely short, and data analysis was adjusted accordingly.

Smithsonian and ScienceAlert

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