What’s as tall as a three-story building, as long as a tennis court, and can see through dust clouds? Why, it’s the James Webb Telescope!
Students in Middle School Science Teacher Sarah Bain’s Grade 8 Seminar course (an extension of her Earth and Space Science class) are learning about this fascinating space tool, which launched in 2021. The telescope can study galaxies, observe the life cycles of stars, and measure the physical and chemical properties of planetary systems. Despite its heft, the James Webb Telescope can fold, origami-style, to fit in a rocket and unfold once it’s in space.
Bryan Innovation Lab
Dean Brad Kovach
recently visited Ms. Bain’s class to give a hands-on lesson about the Webb telescope, which uses infrared wavelengths to study space. Its predecessor, the Hubble Space Telescope, uses visible and ultraviolet wavelengths. Both use massive mirrors to study the universe, but the Webb’s primary mirror has six times the light-gathering power of Hubble’s. The Webb “started out looking like a soup can when it launched,” said Mr. Kovach. “As it made its way into orbit, it unfolded.” Its primary mirror (made up of 18 gold-coated hexagonal segments) collects light and reflects it onto a secondary mirror, allowing it to look deeper into space to see the earliest stars and galaxies.
The Light Stuff
Mr. Kovach also spoke about the properties of light (reflection absorption, and refraction) and how light is essential to the Webb telescope’s ability to see. As students gathered around him, he used mirrors, lenses, and a light box that produced parallel rays of light to illustrate the differences between concave and convex mirrors, which, combined, allow the Webb telescope to have a wide field of view. As he spoke, rays of light appeared on the giant whiteboard behind him, changing shape as he switched between handheld convex and concave lenses.
The very first image to come from the Webb telescope was rather unimpressive, said Mr. Kovach as he displayed the photo of a small group of what looked like 18 randomly scattered stars onto a computer screen.
“When told the image actually shows just one star, our students had a number of excellent hypotheses about why the image looked fuzzy,” he recalled, “from dust on the lens to gravitational lensing from black holes.” To illustrate the correct answer, he hung a bare light bulb from a shelf to represent a star, and students were handed small mirrors, which they used to reflect the light from their own “star” into a square drawn on the whiteboard.
“They realized that there was only one star, but that each student was creating an image on the whiteboard of that star,” explained Mr. Kovach. “The Webb telescope has 18 separate mirrors in an array, therefore, 18 images of the same star. That first image taken by the telescope was used to calibrate the mirrors to align and focus properly. Since then, the telescope has been capturing the most detailed images of the universe ever produced.”
“Using a handheld mirror and teaming up with classmates to see how the Webb telescope works allows students to have those ‘a-ha’ moments that are so exciting,” said Ms. Bain. Jacob Farzad ’28, for example, was amazed at how far away the Webb telescope is from Earth.
“This hands-on lesson helped me learn by seeing a smaller model of the telescope’s features,” said Jacob. “The handheld mirror helped me realize how light can bounce off an object. The size of the universe compared to the Earth is the most fascinating thing I’ve learned in Ms. Bain’s class.” Ellie Hirsch ’28 was awed by the fact that the Webb telescope is so far away, yet can see so much. The mirror experiment made her realize that “the sun can reflect off the mirrors and the light can then go to the telescope.”
Ms. Bain was thrilled that students “took their prior knowledge from our science class and realized how it connects to the real world. These ‘wow factor’ moments always inspire me.”