James Webb Telescope

Context: Researchers have used James Webb Telescope to discover galactic ‘teenager’ galaxies.

What are Teenager Galaxies?

Teenager galaxies are galactic teenagers.
They resemble human teenagers in certain respects, which includes by displaying growth spurts along with a bit of immaturity.
These galaxies have decent number of stars but are still growing rapidly.
The gas detected in these galaxies is much hotter at about 13,350 degree Celsius than observed in galaxies today.
These galaxies have been glowing with 8 elements – Hydrogen, Helium, Oxygen, Nitrogen, Sulfur, Argon, Nickel and Silicon.
Oxygen is the most important component of Galaxy DNA and also helps in tracking past growth.

Considered a successor of the Hubble Telescope.
Most powerful infrared telescope of National Aeronautics and Space Administration (NASA).
Collaboration among NASA, European Space Agency (ESA) and Canadian Space Agency.
Expected to reveal new and unexpected discoveries, and help humanity understand origins of universe and our place in it.

Earth reflects radiation in the far infrared region. So, telescopes cannot operate near this region from ground or low earth orbit. Technology to make telescope see the universe in this region is very sophisticated.
Hubble telescope, most power telescope operational till date, is positioned in low Earth orbit and hence can’t operate in infra-IR region.
James Webb Space Telescope will operate in Far infrared region and will be positioned in L2.
Webb will directly observe a part of space and time never seen before. Webb will gaze into the epoch when the very first stars and galaxies formed, over 13.5 billion years ago. Ultraviolet and visible light emitted by very first luminous objects has been stretched or “redshifted” by universe’s continual expansion and arrives today as infrared light. Webb is designed to “see” this infrared light with unprecedented resolution and sensitivity.
Webb will be a powerful tool for studying the nearby universe. Scientists will use Webb to study planets and other bodies in our solar system to determine their origin and evolution and compare them with exoplanets, planets that orbit other stars.

See the already known universe with higher sensitivity
See far side of the universe, unknown till date.
INSTRUMENTS: It has four science instruments:
Near-Infrared Camera
Near-Infrared Spectrograph
Mid-Infrared Instrument (MIRI)
Near-Infrared Imager
WAVELENGTHS: Visible, Near Infrared, Mid Infrared (0.6-28.5 micrometres)
LOCATION IN SPACE: Orbiting the Sun around the second Lagrange point (L2).
Using a technique called transmission spectroscopy, the observatory will examine starlight filtered through planetary atmospheres to learn about their chemical compositions.

End of Dark Ages: First Light and Reionization - JWST will be a powerful time machine with infrared vision that will peer back over 13.5 billion years to see the first stars and galaxies forming out of the darkness of the early universe.
Assembly of Galaxies: JWST's unprecedented infrared sensitivity will help astronomers to compare the faintest, earliest galaxies to today's grand spirals and ellipticals, helping us to understand how galaxies assemble over billions of years.
Birth of Stars and Protoplanetary Systems: JWST will be able to see right through and into massive clouds of dust that are opaque to visible-light observatories like Hubble, where stars and planetary systems are being born.
Planetary Systems and Origins of Life: JWST will tell us more about the atmospheres of extrasolar planets, and perhaps even find the building blocks of life elsewhere in the universe. In addition to other planetary systems, JWST will also study objects within our own Solar System.

Wavelength	JWST will observe primarily in infrared range and provide coverage from 0.6 to 28 microns.Instruments on Hubble see mainly in ultraviolet and visible part of the spectrum. It could observe only a small range in the infrared from 0.8 to 2.5 microns.Infrared region of electromagnetic spectrum covers wavelength range from approximately 0.7 to a few 100 microns.
Size	Webb’s primary mirror has a diameter of 6.5 metres while Hubble’s mirror was much smaller – 2.4 metres in diameter.So, Webb will have a larger field of view compared to the camera on Hubble.Webb also carries a large sun shield.
Distance	Webb’s near- and mid-infrared instruments will help study the first formed galaxies, exoplanets and birth of stars.Hubble can see the equivalent of “toddler galaxies” while Webb Telescope will be able to see “baby galaxies”.