Last week the James Webb Space Telescope made history with its first images, showing a galaxy cluster billions of light-years away, but now it’s turned its sights on something much closer to home. NASA has released infrared images Webb snapped of Jupiter to test its instruments.
Unlike Hubble, which primarily sees the cosmos in optical and ultraviolet light, James Webb offers an infrared eye. This allows it to peer through clouds of dust that obscure the view of other telescopes, and give astronomers a different view of familiar objects.
Case in point: Webb’s infrared images reveal the planet Jupiter in a new light. The spacecraft’s NIRCam uses multiple filters at different wavelengths of light to capture different details. The short-wavelength filter, at 2.12 microns, shows the gas giant with bright white bands at the poles and around the equator, with darker clouds swirling in between.
The famous Great Red Spot, an Earth-sized storm that’s been raging for centuries, is also clearly visible on the lower right. Here its namesake color has been washed out to white thanks to the way the infrared image was processed. Just to the left of that is a small dark spot, which is actually the shadow of Jupiter’s moon Europa, which is itself visible on the far left of frame.
A longer wavelength filter, at 3.23 microns, reveals fainter structures around the planet. That includes some of its rings, clearest in the area just above Europa, which also shows up much brighter, as do the other moons like Thebe and Metis.
“I couldn’t believe that we saw everything so clearly, and how bright they were,” said Stefanie Milam, Webb’s deputy project scientist for planetary science. “It’s really exciting to think of the capability and opportunity that we have for observing these kinds of objects in our solar system.”
These images show that Webb can distinguish faint structures like these right near bright planets. That could come in very handy – one of the first scientific uses of the technique will see the telescope trying to capture water plumes blasting off from Europa and Enceladus, which are hypothesized to contain large oceans of water beneath their icy shells.
In other tests, Webb was trained on an asteroid called 6481 Tenzing, to see how well it could track fast-moving objects. It was designed to be able to keep up with objects that move as fast as Mars across the sky – 30 milliarcseconds per second. But the telescope was able to track speeds twice as fast as that.
If what we’ve seen in just a week of operations is anything to go by, James Webb is going to be a productive source of stunning space shots and data over the coming years.
Source: NASA