James Webb Space Telescope – UPSC Prelims

James Webb Telescope:
  • James Webb Telescope is an international collaboration between NASA, European Space Agency(ESA), and the Canadian Space Agency.
  • The telescope will complement and is considered the successor of the Hubble Space Telescope.
  • The telescope will use infrared light, which cannot be perceived by the human eye, to study every phase in cosmic history.
  • Mission objectives:
    • observe farther into the universe than ever before
    • Search for the first stars and galaxies created after the big bang
    • better understand how planets, stars, and galaxies are born and evolve over time
    • explore distant worlds and study our solar system
    • determine the potential for life on planets around other stars.
Differences between James Webb Telescope and Hubble Space Telescope?
  • Wavelength: Hubble can observe mainly in the ultraviolet and visible parts of the spectrum. On the other hand, Webb will primarily study the universe in the infrared spectrum. Note: Infrared observations are important because light at this wavelength can penetrate the dust that shrouds newly formed stars and planets and make them visible.
  • Size: Webb telescope will cover more than ~15 times the field of view covered by the Hubble telescope.
  • Orbit:
    • Hubble orbits the Earth at an altitude of ~570 km. Webb will not orbit the Earth, instead it will sit at the Earth-Sun L2 Lagrange point, 1.5 million km away. This means that Webb will orbit the Sun along with the Earth, but will stay fixed at the same spot in relation to the Earth and the Sun.
    • At the L2 point, Webb’s solar shield will block the light from the Sun, Earth, and Moon which will help it stay cool. This is significant for an infrared telescope.
  • Distance: Hubble can see the equivalent of “toddler galaxies”, On the other hand, Webb will be able to see “baby galaxies”. This is because Webb is an infrared telescope, and can see distant objects which are very dim at visible wavelengths of light.

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