What is the James Webb Space Telescope?


If you are curious to know about the state-of-the-art James Webb Space Telescope (JWST), you must read this article.

It is a new generation space telescope to be launched in 2021. It goes beyond Hubble in capturing the longer wavelengths of light! This means the JWST will be much more sensitive than Hubble.

Going back in time, the JWST will be able to explore the first galaxies of this universe. It will be looking straight into dust clouds that are ready to create stars and planets in the times ahead!

The JWST will be able to execute the incomplete agenda of the Hubble telescope revealing the early stages of our universe.

Many questions about our universe still puzzle our scientists. How galaxies began to take shape and how giant black holes formed in the centers of galaxies are still unsolved mysteries before the astrophysicists!

It is still not clear if black holes are the cause of galaxies or vice versa. If we could look into dust clouds with high resolution, then the baffling questions might have answers!

The James Webb Space Telescope will clear the maze whether any of the other planetary systems are hospitable to life or not!


JWST – an Infrared Telescope

Scientists believe that infrared wavelengths can reveal the mystery behind this universe. Because it can show us how stars and planetary systems take shape inside dust clouds, which has not been possible so far through visible or ultraviolet light.

The JWST is being developed precisely to attain this capability!

Is not that interesting as we all are curious to know more about the creativity of nature?

So far none of our telescopes are optimized for infrared light. What we see from our normal telescopes has been possible because they are optimized for ultraviolet or visible light.

And this is the key aspect that differentiates between the JWST and Hubble Telescope!

The ‘redshift phenomenon’ is at the core that has prompted scientists to develop the JWST. And you may want to know what precisely the ‘redshift phenomenon’ is!

We all know that visible light is made of different colors. We are aware of the famous experiment that most of us have done in our school days using a prism that shows us how the light gets separated into seven colors!

Often, the same spectrum is seen as rainbow immediately after the rains when the Sun peeps through clouds.

When an object comes closer, the blue end of the spectrum becomes prominent, and when an object moves farther, the red end of the spectrum becomes more prominent. This is known as the redshift phenomenon!

It was the Edwin Hubble, the US astronomer, who first described the redshift phenomenon in 1929!

It was he who also first informed the world that all galaxies are moving farther and farther.

Since the universe has been expanding and galaxies are moving away from each other, we need to have an instrument that can detect infrared light. Our attempts to observe the origin of the universe can then fructify someday!

Scientists say that the formation of stars and planets takes place within the dusty clouds. Infrared light is not blocked by the small dust particles and can escape from there. That is how we can look into dust clouds and understand how stars and planets are formed.

As such, the JWST is similar to Hubble Telescope in many ways, but it will deliver images in infrared. These images will be certainly different from the images usually seen by our eyes.

But no need to worry as these infrared images can be transformed into a visible picture through a computer program.


Some Interesting Information about JWST

The JWST is a reflecting type of telescope. With a 6.5 meter diameter of the mirror, the JWST will be sensitive to the mid-infrared wavelengths between 0.6 micrometers to 28.5 micrometers.

Its mirror is significantly large so as to enable it to see the faint light emanating from the early star-forming regions and have finer details at infrared wavelengths.

It has an unfolding mirror for its large size and the ease of launch!

To accommodate its unfolding mirror during launch, it has been made in the hexagonal shape because its different segments can fit together without having any gaps. Circular shape will have gaps in between and will not be suitable at all!

The JWST is a collaborative project that involves the European Space Agency, NASA, and the Canadian Space Agency.

There are the telescopes, currently, sensitive in the far-infrared wavelengths between 55 micrometers and 670 micrometers wavelength. Herschel falls in this category and can detect the beginning of star formation in dark clouds.

The JWST will go beyond to see the proto-stars in very far off galaxies. Data from both the telescopes will help formulate a clearer picture of the formation of stars.

The James Webb Space Telescope architecture is such that at least 40% of the sky will be in the visibility range at any given time. In addition, all regions of the sky will have a minimum of 51 days of continuous visibility in a year.

The JWST will be launched in space through a European Space Agency Arianne rocket from French Guiana sometimes in the month of March 2021. It has been designed to last at least for 5-1/2 years.

The optimum life of the telescope is estimated as ten years!

The actual life of the JWST will largely depend upon how fast the components of the JWST wear out in the hostile environment of space.

It will reach its orbit roughly in one month after the launch. The JWST is destined to be placed in an L2 orbit, which lies at 1.5 million km from the Earth.

It will start its imaging and other operations after six months of the launch. In between, it will remain busy calibrating its instruments and aligning its mirrors.

Apart from deep sky objects, it will also observe and image the objects in our solar system that include comets, asteroids, satellites, Kuiper belt objects.

In addition, the JWST will also keep a watch on the weather of other planets and moons. Its orientation will be such that it will not be able to observe the Sun, Moon, Mercury, Venus and many near-earth objects.

The scientists from the NASA hope that the JWST will be able to see back in time up to the period that can be described as somewhere between 100 million years and 250 million years after the Big Bang.

Hubble has been orbiting in a low-earth orbit – almost 600 kilometers from the Earth, and for this reason, it is within the serviceable range. In the case of the JWST, it will be circulating in orbit as far as 1.5 million kilometers from the Earth. Hence, it will not be accessible at all for the servicing purpose!

This means risks involved with the JWST are significantly higher. That is why its launch date has been postponed several times in the past.

The JWST will be equipped with a ‘Sunshield’ as large as the tennis court. The ‘Sunshield’ will be made of five layers of an insulating film known as Kapton. In addition, the five layers will be separated by vacuum so as to serve the purpose of insulation. Five layers of Kapton are optimum to prevent it from getting heated!

The James Webb Space Telescope is going to be a game-changer to unfolding the mysteries of the origin of the universe that we all are extremely curious to know about!