December 18, 2021: This is the anticipated launch date of the James Webb Space Telescope, the largest and most sophisticated space telescope view the universe.
by Jeffrey L. Hunt
NASA, in cooperation with the European Space Agency (ESA) and the Canadian Space Agency, announced December 18 as the tentative launch date for the James Webb Space Telescope by an ESA launch vehicle.
Named for a former NASA administrator, the telescope is constructed from 18 separate beryllium patches or segments of mirror. After launch the segments are unfolded and formed into the reflected surface. A sunshade blocks sunlight from reaching the mirror and the scientific instruments used to view the sky.
The telescope’s primary function is to look at the infrared part of the spectrum, a color or wavelength of light that humans cannot see, but feel has heat, like that from a bonfire. The wavelengths are filtered by Earth’s atmosphere and only weakly reach the ground. Infrared telescopes are typically placed on mountain tops, above most of the water vapor that absorbs infrared radiation.
Unlike colors visible to the human eye, infrared light passes through dust clouds and gives astronomers views of newly-forming stars and possibly planets. The telescope will look for galaxies that appear to be forming. Because this occurs at great distances, these forming galaxies occurred near the beginning of the universe. The telescope will be looking back into time and distance.
The mirror of a telescope is equal to a single round telescopic mirror that is 6.5 meters (21 ft) across. In comparison, the Hubble Space Telescope’s mirror is 2.4 meters (8 ft). Webb can see objects that are nearly 10 times dimmer than Hubble’s sensitivity.
The telescope can view up to 100 celestial objects simultaneously. Like the astonishing images from Hubble, Webb promises to unlock answers to lingering questions about the state of the universe as well as to bring new questions about the space around us.
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