Webb Telescope Test Image Stuns Astronomers
Behind a tightly-focused star in a test image,
thousands of spiral galaxies are visible.
“We have the highest resolution infrared images taken from space – ever,” says Scott Acton on a video posted by NASA. “We have exceeded every expectation. The telescope has performed better than the models said it should.”
Released with the announcement is a stunning image of a star photographed to check the alignment of the 18 hexagonal mirror segments. Its diffraction spikes are extremely thin, indicating excellent alignment and resolution.
Test image from James Webb Space Telescope released March 16, 2022.
The caption reads,
While the purpose of this image was to focus on the bright star at the center for alignment evaluation, Webb’s optics and NIRCam are so sensitive that the galaxies and stars seen in the background show up. At this stage of Webb’s mirror alignment, known as “fine phasing,” each of the primary mirror segments have been adjusted to produce one unified image of the same star using only the NIRCam instrument. This image of the star, which is called 2MASS J17554042+6551277, uses a red filter to optimize visual contrast.
Seth Borenstein quipped that the telescope’s image of a star got “photobombed by galaxies” (Phys.org, 16 March 2022). The first science images are expected late June or early July, but this was enough to get the scientists really excited. “We’re thrilled to death,” Acton said in the video, as scientists applauded behind the images. “….I cannot wait to see what it discovers.”
Live Science quotes Lee Feinberg, engineer on the telescope team, saying, “We’ve actually done very detailed analysis of the images we’re getting, and so far, what we’re finding is that the performance is as good [as], if not better than, our most optimistic prediction.”
The image made scientists “giddy” said New Scientist on March 17. New Scientist reporter Leah Crane the previous day quoted team scientist Jane Rigby commenting, “The telescope performance so far is everything that we dared hope for.”
Taxpayers are sure to be relieved that the return on the $10 billion dollar cost of this long-delayed tool looks satisfying so far. The remaining instruments on the telescope need to be aligned as a group before scientific observations begin this summer.
James Webb Space Telescope Mirror Seen in Full Bloom. From Wiki Commons.
Why Infrared?
At The Conversation last December, Martin Barstow explained why an infrared telescope this size “could uncover some of the universe’s best-kept secrets.” Cooler, faint objects than bright stars can be detected in the infrared spectrum. These include planets, faint galaxies and stars. Barstow says that infrared allows astronomers to “see through the clouds of dust that enshroud very young stars, which are opaque to visible light.” Another goal is to find Earth-like planets.
A significant fraction of the JWST observing programme will be devoted to the study of their atmospheres. The wavelength coverage of JWST is particularly well tuned to studying molecules in exoplanet atmospheres and the low infrared background from space, giving it a considerable advantage over Earth-based telescopes.
Dr Bijan Nemati, physicist formerly at JPL who appeared in the Illustra documentary The Privileged Planet, was interviewed by Jay Richards about things to expect from the James Webb Space Telescope. The interview was posted on the ID the Future podcast on February 28. He mentions that centuries after Newton described planetary orbits, and Immanuel Kant speculated about planets accreting from dust, today’s scientists still do not understand how planets form. Dust particles are not known to stick together in order to build planets. Planet formation is still a very challenging question.
Our first post about the JWST (16 Dec 2021) doubted that it would take photos as beautiful as the Hubble, but maybe we were wrong. That’s a stunning test image. Time will tell whether JWST photos will hang on office walls.
All the scientists, including ID advocate Dr Nemati, accept the big bang and billions of years as a given. One should keep in mind that interpretation of evidence is different from the evidence itself. The photos hitting the telescope arrive in the present and are seen in the present. How they got there, and how long it took, cannot be directly observed. Those questions belong to history, not to science. One’s worldview strongly colors the interpretation given to an observation.
Nevertheless, the building of the telescope, the careful alignment of its mirrors, and the mathematical models conceived to get the JWST to this point are excellent examples of the precision available in observational science. We look forward to the first scientific images to be taken by this powerful new tool in space and wish the scientific team a prosperous voyage.