![]() ![]() The telescope will be controlled remotely by commands sent over a radio link. NASA/STScI, CC BYĪfter testing came the rehearsals. Rehearsals and training at the Space Telescope Science Institute are critical to make sure that the assembly process goes smoothly and any unexpected anomalies can be dealt with. 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. It may even be possible to figure out the composition of these atmospheres.Įver 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. This design will allow scientists to study how stars form in the Milky Way and the atmospheres of planets outside the Solar System. Light from a star or galaxy will enter the mouth of the telescope and bounce off the primary mirror toward the four sensors: NIRCam, which takes images in the near infrared the Near Infrared Spectrograph, which can split the light from a selection of sources into their constituent colors and measures the strength of each the Mid-Infrared Instrument, which takes images and measures wavelengths in the middle infrared and the Near Infrared Imaging Slitless Spectrograph, which splits and measures the light of anything scientists point the satellite at. The Webb telescope has a mirror over 20 feet across, a tennis-court sized sun shade to block solar radiation and four separate camera and sensor systems to collect the data. ![]()
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