James Webb: Unlocking Our Universe’s Past
The James Webb Space Telescope with a background of the galaxy
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Chirp chirp. The sound of crickets rings in your ears as you lie in the tall summer grass, gazing up at the starry night sky. Your eyes trace the stars until they land on the bright moon. You cannot help but wonder how these celestial bodies were formed. We have plenty of information dating back to the start of human evolution but not to the origins of our universe. To dive deeper into the formation of the first stars and galaxies, we must use specially designed instruments made to peer far into orbit; the James Webb Space Telescope does just that.
The second administrator of NASA, James Edwin Webb, sought to advance human space flight to improve the nation’s aerospace industry, dreaming of Americans in space. Webb’s focus on using robotic spacecraft to conduct research led to success in human space travel and celestial discoveries. During Webb’s time at NASA, 75 space missions, including the Apollo program—the program where Americans set foot on the moon—explored the mysteries of outer space. In 1965, these missions inspired Webb’s idea of a major space telescope that could reach farther into the universe than what was previously possible. Following his retirement, Webb’s ideas came to life when NASA produced the Hubble Space Telescope: a large, space-based observatory used to observe distant stars, galaxies, and planets. As Webb’s leadership and proposals laid the foundation for astronomical discoveries, former NASA administrator Sean O’Keefe finds it fitting that the Next Generation Space Telescope is named after him.
Expanding upon the discoveries made by the Hubble Space Telescope, the Webb telescope aims to observe planetary atmospheres—an envelope of gasses surrounding planets. With the infrared wavelengths it can observe, the telescope can identify important molecules, ices, and minerals at or beyond the orbit of our solar system, which was previously impossible. These observations are significant because by looking at ice, we can study eroded parts of many planets. Uranus and Neptune, for example, contain water, ammonia, and methane, which are icy, whilst other planets may have volcanic-like geysers that erupt ice.
By using infrared waves, the Webb telescope can illustrate the formation of planetary systems inside opaque nebulas—dust and gas clouds formed by the explosion of dying stars—which posed problems for past telescopes. Infrared waves are not visible to the human eye and many celestial bodies are too faint to be detected in visible light. As the telescope looks farther into the universe, ultraviolet and visible light is emitted toward red wavelengths, causing the visible light to become red-shifted. To address this, a Near Infrared Camera (NIRCam) is used to interpret the infrared wavelength at its appropriate range, which is 0.6 to five microns. The NIRCam is necessary for looking at the formation of the earliest stars, populations of stars in nearby galaxies, and Kuiper belt objects—icy bodies beyond the orbit of Neptune. It works by using coronagraphs, which are instruments that block brighter objects’ light to make it possible to view dimmer objects nearby.
The telescope has three curved mirrors and hexagonal, segmented mirrors, resulting in six-fold symmetry. This specific mirror arrangement is essential to capture faint light from the first star-forming regions. The mirrors are capable of folding and unfolding, which allows for the telescope to fit into a rocket and expand after launch. As the instruments and telescope must be stored at cold temperatures—about 40 degrees above absolute zero—a protective sun shield blocks the inner solar system from view. It is composed of five extremely thin layers of insulating film called Kapton, with each successive layer cooler than the one below. Taking into account the unpredictable asteroids within space, the Webb telescope has also been designed to survive any impact from celestial bodies. For example, on space flights, the machine uses cryogenic beryllium mirrors, which are mirrors made of the relatively rare metal beryllium. The beryllium in the telescope is a fine powder of high quality, which helps the instrument hold its shape in a range of cryogenic temperatures—-150˚C to absolute zero. With these mirrors, if the telescope makes contact with micrometeoroids—small rock particles in outer space—the effects are negligible.
Last year, the Webb telescope discovered six rapidly growing galaxies born unexpectedly soon after the Big Bang. These observations challenge initial theories and cosmological models of the origins of our universe, as they indicate that matter has been moving and expanding much faster than we have ever thought. Associate Professor Ivo Labbe at Australia's Swinburne University of Technology estimates that the galaxies would have had to grow around 20 times faster than the Milky Way, at a rate of approximately 35,000 km/hr. Many scientists are working to find alternative explanations for this phenomenon, one of which being that the clumping of dark matter and energy is responsible for these galaxies. As demonstrated by the Webb telescope, the vastness of space and the mysteries of the universe have yet to be fully discovered. But as scientists continue to engineer and improve technological tools, we will slowly unlock the secrets of the cosmos.