Rather It Is Hubble’s Succesor Not Replacement: NASA on James Webb

The James Webb Space Telescope (JWST) was launched on December 24 at 7.20 am EST (5.50 pm India time). The Hubble Space Telescope, NASA’s flagship telescope that has been operating for more than three decades, will be replaced by Webb, the largest space science observatory in the world.

According to NASA, James Webb is not a replacement for Hubble but rather its successor, whose scientific objectives were inspired by Hubble’s findings. While Hubble focuses mostly on optical and ultraviolet wavelengths, Webb will primarily investigate the universe in the infrared.

Hubble Vs James Webb: Comparing World’s 2 Powerful Space Telescopes

How James Webb Is Superior To Hubble?


Since Webb’s mirror is far bigger than Hubble, it can see further into the past than Hubble. Additionally, compared to Webb, Hubble will be orbiting the Earth considerably more closely.


Webb’s four instruments will be able to observe primarily in the ultraviolet and visible regions of the electromagnetic spectrum from 0.1 to 0.8 microns, whereas Hubble’s instruments can primarily observe in the infrared region of the electromagnetic spectrum, which is from about 0.75 microns to a few hundred microns.

Because light at this wavelength can get through the dust that envelops freshly created stars and planets and make them visible, infrared measurements are crucial.


Compared to the mirrors of the current generation of space telescopes, Webb’s primary mirror has a collecting area that is around 6.5 metres in diameter. With a mirror that is 2.4 meters in diameter, Webb’s collecting area is around 6.25 times larger than Hubble’s.

The field of vision that Webb will cover is greater than 15 times than that of the NICMOS camera on Hubble, which is roughly the size of a tennis court. Webb’s sunshield measures about 22 m by 12 m.


Hubble circles the Earth at a height of around 570 km. Instead of orbiting the Earth, Webb will be 1.5 million kilometers from the Earth-Sun at L2 Lagrange point.

Accordingly, Webb will orbit the Sun in tandem with the Earth while remaining fixed in place with respect to the Earth and Sun. In order to keep Webb cool at the L2 point, its solar screen will exclude light from the Sun, Earth, and Moon.

Distant Field Of Vision.

Since light travels slowly, the more away an object is, the further back in time we are viewing it. As a result, Webb will be able to detect “baby galaxies” while Hubble can only see the equivalent of “toddler galaxies.” This is especially true since Webb is an infrared telescope, which means it can detect faint, far-off objects that are visible to the human eye.

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