Monday, November 6, 2023

Tuesday is Prime Time for Euclid

Tuesday morning Eastern Time, we get to see through the European space telescope Euclid's "eyes" for the first time.

Euclid mission scientists are gathering in Darmstadt, Germany, to discuss the telescope's first five full-color images of the distant cosmos, and you can watch Tuesday's reveal live at 8:15 a.m. EST (1315 GMT) here on, courtesy of ESA. In addition to holding scientific value, the images are also expected to be great cosmic eye candy.

Euclid launched on July 1st at 11:11 AM EDT, enroute to the L2 Lagrange point nearly a million miles from Earth and coincidentally the home of NASA's (much) larger James Webb Space Telescope. Euclid teased us with its first alignment and commissioning test images one month later, and then caused at least a little concern just over one month after that when the satellite temporarily lost track of its guide stars.  Every indication is that the telescope is working fine and ready to download some fine examples of eye candy. 

Two images taken by Euclid's instruments from that August image release. The left was taken by VIS, the VIsible light Sensor and the right by NISP,  the Near-Infrared Spectrometer and Photometer.  (Image credit: ESA/Euclid/Euclid Consortium/NASA) 

Euclid has been tasked with building an innovative 3D map of the dark universe by charting out shapes and distributions of billions of galaxies and star clusters up to 10 billion light-years away, primarily in search of clues about elusive dark matter and dark energy.

To achieve that goal, the telescope is primed to take enough sharp images of large swaths of the sky in visible and infrared wavelengths to fill a million DVDs. To investigate the dark universe, Euclid will observe weak gravitational lensing, a cosmic phenomena which occurs due to the chance alignment of galaxies or conglomerations of matter, which allows foreground galaxies to behave like a giant magnifying lens of objects behind them. Light from background sources is distorted, even multiplied on its way to Earth, such that we see their twisted, surreal illusions around lensing galaxies.

Since visible matter comprises just 10% or so of the total mass of most galaxy clusters, scientists suspect invisible dark matter particles are responsible for much of this lensing. So, studying galaxy clusters could shed light on the behavior and nature of dark matter — but those images need to be super-sharp to bring fuzzy lensed images around galaxies into focus.

Bear in mind that while that last paragraph sums up the conventional view of dark matter and dark energy, "just across the way" out at L2, the JWST is sending down images that are calling several details in the conventional model into question. That's a good thing because it means we're learning.

EDIT TO ADD, Nov. 7, 2023:  The link to has no video of the Euclid presentation.  Currently the ESA is streaming, ready to go live, HERE.


  1. Interesting! Thanks for the update.

  2. Very interesting. I am not a Cosmologist, but find some of this work fascinating!