![]() ![]() ![]() We need to wait 35 days after launch for the parts to cool before beginning alignment. The Webb team continued to rehearse and practice until the launch date, but our work is far from done now. NASA/Chris Gunn, CC BY Some alignment required To fit inside a rocket, the telescope needs to fold into a compact package. ![]() Just like the pitch of an ambulance’s siren shifts down and becomes deeper when it passes and starts moving away from you, the wavelength of light from distant galaxies shifts down from visible light to infrared light. The telescope also has to cope with another complication: Since the universe is expanding, the galaxies that scientists will study with the Webb telescope are moving away from Earth, and the Doppler effect comes into play. Distant objects also appear to be very small, so the telescope must be able to focus the light as tightly as possible. Webb’s mirror is made of 18 separate segments and can collect more than six times as much light as the Hubble Space Telescope mirror. I estimate that images my colleagues and I will collect with NIRCam could show protogalaxies that formed a mere 300 million years after the Big Bang – when they were just 2% of their current age.įinding the first aggregations of stars that formed after the Big Bang is a daunting task for a simple reason: These protogalaxies are very far away and so appear to be very faint. It takes billions of years for the light from these galaxies to cross the universe and reach Earth. One of the main goals of the telescope is to study distant galaxies close to the edge of observable universe. NASA/Chris Gunn, CC BYĮver since Edwin Hubble proved that distant galaxies are just like the Milky Way, astronomers have asked: How old are the oldest galaxies? How did they first form? And how have they changed over time? The Webb telescope was originally dubbed the “First Light Machine” because it is designed to answer these very questions. The NIRCam, seen here, will measure infrared light from extremely distant and old galaxies. ![]()
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