James Webb has Jupiter in his sights, why?

The James Webb telescope was launched on December 25, 2021 in view of the successor to the Hubble telescope whose life has been extended several times. Although it can’t completely replace it (Hubble is equipped to take measurements in the UV unlike the James Webb), the telescope should soon start its active service.

The James Webb telescope has safely entered orbit, deployed its hardware, aligned its mirrors, there are only a few steps left, such as calibrating the measurement instruments before it can be fully functional this summer, if all going according to plan.

13 projects to test the telescope

To test the power of the newcomer, many scientists came up with their project. Thirteen of these have been selected, nine of which in the first five months after commissioning.

If most of them want to observe black holes, distant galaxies and faint objects to take advantage of the unprecedented power of this new observation equipment, one of these projects is interested in a much closer one: Jupiter.

Jupiter: both famous and mysterious

Of all the objects of future study, Jupiter is both the closest and the most “known” planet. With the many observations that have been made (Hubble, Galileo, etc.), scientists have a lot of data about the gas giant, without having found the answer to all the questions.

Therefore, by using a new instrument like the James Webb telescope, scientists will have a basis for comparison while accessing new information about Jupiter: its red spot, its south pole, heat exchanges between different layers of the atmosphere. .

An opportunity also for scientists to study the immediate environment, such as the rings or the moons. Io is the most active volcanic system in the solar system, and Ganymede is the only moon known to have successfully produced its own magnetosphere. So much useful information for observing distant worlds (and why not in the distant future, for terraforming worlds).

Take advantage of the infrared range

When you look at an object, it can have different levels of opacity: fully or partially transparent to opaque. While visible light cannot see through Jupiter’s atmosphere, it is possible to use infrared to see things differently.

The infrared radiation can indeed penetrate deeper into Jupiter’s atmosphere before being stopped. By scanning multiple wavelengths, the telescope can generate an image of the atmosphere as a function of altitude and map it in three dimensions.

Mid-infrared observations are possible from our planet, but our atmosphere makes it nearly impossible to calibrate the observations. Because the James Webb is in space and equipped with a MIRI (Mid-Infrared Instrument), it can overcome this limitation and deliver sharp images of unparalleled precision on Earth.

A very, even too sensitive telescope

These projects are also a good way to test the limits of the device. One of them is surprising, the device is too sensitive. Planned at the base to observe very distant elements, the James Webb appears to be too sensitive to conduct all observations on Jupiter.

Just as it is difficult to capture the details of a person’s face against the light, the observation device struggles to perceive elements that are not very bright (such as rings or moons compared to a planet, or a planet relative to its star).

Fortunately, scientists have solid experience with Hubble that they can adapt to the new tool to make accurate measurements while taking the environment into account.

The gateway to distant systems

Taking an interest in Jupiter and what revolves around it is therefore by no means a waste of time for scientists. These observations will allow them to get their hands on the instrument and test its limits while collecting valuable data about our solar system.

Based on data from Jupiter, the team responsible for the project plans to develop a set of tools that can be adapted to Uranus and Neptune, which have been very little studied.

We wish the James Webb telescope a “career” as full as Hubble’s.