Peering into the Past: The James Webb Space Telescope

Lexile: 1080 | Grade: 10

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Launched in December 2021, the James Webb Space Telescope (JWST) is the most powerful telescope ever sent into space. It was designed to explore some of the oldest and most distant parts of the universe, helping scientists look billions of years into the past.

Unlike the Hubble Space Telescope, which sees mostly visible and ultraviolet light, the JWST focuses on **infrared light**. Infrared light has longer wavelengths, which allows it to pass through clouds of gas and dust that often block other forms of light. This ability makes JWST perfect for studying the formation of stars, galaxies, and planets that formed shortly after the Big Bang.

JWST orbits far beyond Earth—about 1 million miles away. At this distance, it avoids the heat and light from Earth and the Moon, which can interfere with its sensitive instruments. To keep cool, the telescope carries a massive sunshield the size of a tennis court. This shield protects its mirrors and sensors from the Sun’s heat, allowing it to operate at temperatures near absolute zero.

One of JWST’s key goals is to study the **atmospheres of exoplanets**—planets that orbit stars outside our solar system. By analyzing how starlight passes through a planet’s atmosphere, JWST can detect gases like water vapor, carbon dioxide, or even methane. These gases could provide clues about whether a planet might support life.

In addition to studying exoplanets, JWST is helping astronomers answer big questions: How did the first galaxies form? What are black holes really like? How common are solar systems like ours? The telescope’s high-resolution images and deep sensitivity are already transforming what we know about the cosmos.

But building and launching the JWST was no small feat. It took over 20 years of planning, international collaboration, and billions of dollars. Engineers had to fold the telescope to fit inside a rocket and then unfold it in space—a process that involved over 300 possible failure points.

Despite the challenges, JWST has become a symbol of scientific ambition and cooperation. Its mission is far from over, and the data it collects may change how we think about the universe—and our place in it—for decades to come.