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Analyzing Light

JWST

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The James Webb Space Telescope (JWST) is the most powerful space observatory ever built, designed to look deeper into the universe than any telescope before it. Launched in December 2021, JWST is a joint project of NASA, ESA (European Space Agency), and CSA (Canadian Space Agency).

Why JWST Matters

JWST is the scientific successor to the Hubble Space Telescope, but it is not just a bigger version. It is specifically designed to observe the infrared universe, which allows astronomers to:

  • See the first galaxies that formed after the Big Bang

  • Study stellar nurseries where stars and planets are being born

  • Analyze the atmospheres of exoplanets, searching for signs of habitability or even life

Key Features

  • Large mirror: Its gold-coated primary mirror is 6.5 meters across—more than twice the size of Hubble’s—allowing it to collect much more light.

  • Infrared focus: Observes mainly in infrared light, which can pass through cosmic dust and reveal cooler, older, and more distant objects.

  • Sunshield: A multi-layered sunshield the size of a tennis court blocks heat and light from the Sun, Earth, and Moon, keeping the telescope cold enough for sensitive infrared observations.

  • Location: JWST orbits around the second Lagrange point (L2), 1.5 million kilometers from Earth, far beyond the Moon, providing a stable and cold environment.

Scientific Goals

JWST’s main science themes include:

  • Early Universe: Discovering the first galaxies and mapping their growth over time

  • Galaxy Evolution: Studying how galaxies form, merge, and change

  • Star and Planet Formation: Observing protoplanetary disks and stellar birth regions in detail

  • Exoplanets: Measuring the composition and structure of planets orbiting other stars, including Earth-sized worlds in the habitable zone

With its unprecedented sensitivity and resolution in the infrared, JWST is already reshaping our understanding of the cosmos—from revealing the structure of distant galaxies to detecting water, carbon dioxide, and other molecules in exoplanet atmospheres.

 Self-Evaluating Questions

Try answering these questions after completing the reading. If you find any difficult to answer, revisit the textbook to reinforce your understanding.

  • a. Visible light
    b. Ultraviolet light
    c. Infrared light
    d. Gamma rays

  • a. To prevent its electronics from overheating
    b. To observe high-energy X-rays
    c. To allow accurate infrared observations without interference from the telescope’s own heat
    d. To keep the telescope in hibernation mode

  • a. JWST orbits Earth like Hubble
    b. JWST is in low-Earth orbit, closer than Hubble
    c. JWST orbits the Moon
    d. JWST orbits the Sun-Earth L2 point, far beyond the Moon

  • a. It is closer to stars
    b. It has a gold-coated mirror
    c. It has a larger primary mirror
    d. It uses adaptive optics

  • a. Studying the early universe and first galaxies
    b. Observing star and planet formation
    c. Detecting gravitational waves from black hole mergers
    d. Analyzing the atmospheres of exoplanets

    1. c. Infrared light

    2. c. To allow accurate infrared observations without interference from the telescope’s own heat

    3. d. JWST orbits the Sun–Earth L2 point, far beyond the Moon

    4. c. It has a larger primary mirror

    5. c. Detecting gravitational waves from black hole mergers