Scientists, elated by James Webb, got 'a little carried away' with their data

Scientists, elated by James Webb, got ‘a little carried away’ with their data

The James Webb Space Telescope may be revolutionary, but it’s not without its flaws. Its instruments were not yet fully calibrated when the first data became available, leading scientists to some small errors.

The general public discovered the first images taken by the James Webb Space Telescope on July 12, 2022. The loud announcement attracted worldwide media attention, including outside the specialized press. Two days later, the first “real” data from James Webb was released and made available to researchers, who set out to dissect it.

The first studies took less than a week to be published on the ArXiv server. This server is dedicated to scientific articles that have not yet been peer-reviewed and therefore not published in journals. However, these documents will, for the most part, need to undergo significant review before being validated. Because it turns out that the data is incorrect, as the journal Nature pointed out on September 28.

First data of the provisional James Webb

We may have gotten a little carried awayacknowledges Véronique Buat, a researcher at the Marseille astrophysics laboratory. There was such excitement with this data that we published very quickly, and now we have to revise most of our results. »

Could the JWST have failed in its mission? Absolutely not. This is a problem related to the calibration of the instruments. Before takeoff, the various sensors on the telescope are adjusted. But, during the orbit, between the movements and then the temperature changes, everything moves and you have to start making the adjustments again to be able to use all this technology correctly.

This obstacle is well known to the scientific community. Every mission is entitled to its little imperfections at the beginning, and sometimes you have to wait several months to have something really exploitable. But, even three months later, James Webb’s calibration is not completely finished and the data is constantly revised. ” We had data loaded very quickly.says Veronique Buat. It’s quite unusual to go that fast and we thought they were strong enough already, but they weren’t. »

Specifically, the scientist works in distant galaxies. These are the results that have been impacted the most, as they are extremely weak signals that require the highest accuracy. Last July, Numerama told them about a study on the most distant galaxy ever detected, specifying that it was only a pre-publication that had to be taken with caution. If this particular study is still pretty cautious and hasn’t been withdrawn, Véronique Buat had to review some of the results of it (which are no longer accessible online because they haven’t been published): “ We had a redshift (the redshift, which is used to date galaxies) of 14, which is very far. But, with the revision, we go to 12, which is a pretty significant gap for physicists. »

Focus on GLASS-z13.  // Source: NASA/CSA/ESA/STScI
Zoom in on GLASS-z13, the distant galaxy that James Webb would have detected. // Font : NASA/CSA/ESA/STScI

At first, many of the signals corresponded to very distant galaxies, but after a recalibration of the instruments, it turned out that these objects were finally a little less spectacular than they seemed. Other studies involving closer objects had stronger results that did not need to be revised as the data was clear enough. The question arises more for distant signals.

At the moment, we have almost a new calibration every week.says Veronique Buat, and it should take a little longer before we have reliable data. »

“You have to be careful and wait”

Typically, the first data arrives several months or even a year after the final installation of the mission. But, for the JWST, everything happened very quickly, which surprised the community. ” Calibration can sometimes take the entire mission, even aftersays Olivier Berné, an astrophysicist at IRAP in Toulouse. We can always do better and we know that in the beginning it is better not to over-interpret the data. »

The researcher obtained the direction of one of the first programs destined to be studied with the JWST. He has yet to publish any studies, but he was tempted to see the flow of publications from the early days. ” There is a very frustrating side, because we have been working on our project for years and some people rush to be the first to post. But, we have to be careful and wait to be sure of what we say. »

For the researcher, this precipitation is indicative of a competition problem within the scientific community. ” This is especially the case in the United States: if a researcher wants to have a job, they must publish and be cited, which encourages them to be first and therefore to hurry. »

The JWST, in the stowed position.  // Source: Northrop Grumman via Flickr (cropped photo)
The JWST, in the stowed position. // Source: Northrop Grumman via Flickr (cropped photo)

In France, the status of researchers is more protected. Still, that didn’t stop early releases. ” As the teams are international, there is a sense of urgency.says Veronique Buat. We have a common Slack where there were messages 24 hours a day, from the United States, from Japan… All of this gives the impression that we have to go fast, I had never experienced that in my entire career! »

What to get out of this case? For Véronique Buat, this confusion should not make us forget the prowess of the JWST: “ An entire career can be done in a single imagesays the researcher. His results are amazing and once all his instruments are optimized, we will discover many things.. »

For Olivier Berné, this ultimately proves that the scientific method and peer review system are sound. ” The revisions were quick, the magazines did not miss these works that remained in a pre-publication state. This is proof that the system can withstand this overtravel. The astrophysicist expects his first publication on the subject to be ready by the end of October, once the storm has calmed down a bit.


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