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JAMES WEBB TELESCOPE

JAMES WEBB TELESCOPE

1. Background

The James Webb Space Telescope took 30 years and $10 billion to build, has flown over 1.5 million kilometres away from Earth, and now, we will finally be seeing the first glimpse of its power with a collection of images.
NASA has promised the deepest image of our universe that has ever been taken, and these first sets of images are only the first step in a long job of expanding our view of the universe.
Webb inspires the world through discovery. The telescope will capture the highest resolution science images of the infrared universe on an unprecedented scale.
The Webb telescope can view stars, galaxies, and planets in the infrared light spectrum. Its cameras and spectrographs are built to operate at extremely cold temperatures to conduct infrared science.
Webb is one of the great engineering feats of humanity.
Engineers invented 10 new technologies to detect infrared light of distant astronomical objects that benefit us here on Earth – with applications in medicine, aerospace, and other fields.
Innovative spinoff technology has produced advances in eye surgery and better diagnoses of eye diseases

2. Scientific Goals of James Webb

Webb will seek light from the first galaxies in the early universe, and it will explore our solar system, as well as nearby planets orbiting other stars.
Themes highlighted in the first images and spectra include cutting-edge explorations of the early universe, the evolution of galaxies through time, the lifecycle of stars, and other worlds outside our solar system
Webb’s unprecedented sensitivity to infrared light will help astronomers understand how galaxies assemble over billions of years.
Webb will see through dust clouds, where stars and planetary systems are born.
In addition to learning about our solar system, Webb will study the atmospheres of planets orbiting other stars, called exoplanets.
Webb will reveal new and unexpected discoveries to help us understand our cosmic origins, seeking to answer age-old questions: How did the universe begin? How do galaxies form and evolve? How do we fit in the cosmos?

3. Quick Facts about James Webb

Webb will orbit the Sun at the second Lagrange point, called L2, which is located one million miles from Earth.
Webb’s sun shield is the size of a tennis court.
It protects the sensitive equipment by creating a difference in temperature between the hot and cold sides of the spacecraft of almost 600 degrees Fahrenheit!
Using its infra-red telescope, the JWST observatory will examine objects over 13.6 billion light-years away.
Because of the time it takes light to travel across the Universe, this means that the JWST will effectively be looking at objects 13.6 billion years ago, an estimated 100 to 250 million years after the Big Bang.
This is the furthest back in time ever observed by humanity.
After launching into space, the JWST will orbit the Sun, flying up to 1.5 million kilometres from Earth in temperatures reaching -223°C.
For comparison, the Moon is 384,400km away, while the Hubble Space Telescope flies only 570km above our planet. As the JWST will operate so far away from Earth, it will not be able to be serviced by astronauts if any faults arise.

3.1 About Lagrange Point

L2 is one of the so-called Lagrangian points, discovered by mathematician Joseph Louis Lagrange.
Lagrangian points are locations in space where gravitational forces and the orbital motion of a body balance each other.
Therefore, they can be used by spacecraft to 'hover'.
L2 is located 1.5 million kilometres directly 'behind' the Earth as viewed from the Sun.
It is about four times further away from the Earth than the Moon ever gets and orbits the Sun at the same rate as the Earth.
It is a great place from which to observe the larger Universe. A spacecraft would not have to make constant orbits of the Earth, which result in it passing in and out of the Earth's shadow and causing it to heat up and cool down, distorting its view. Free from this restriction and far away from the heat radiated by Earth, L2 provides a much more stable viewpoint.

4. Mission of James Webb telescope

As the JWST is a product of an international collaboration between NASA, the European Space Agency (ESA), and the Canadian Space Agency (CSA), it has many mission goals.
These include:

Examine the first light in the Universe and the celestial objects which formed shortly after the Big Bang.
Investigate how galaxies form and evolve.
Study the atmospheres of distant exoplanets.
Capture images of planets in our solar system.
Locate evidence of dark matter.

The JWST is expected to operate for five years after its launch. However, NASA hopes the observatory will last longer than 10 years.
Unfortunately, the observatory won’t be able to operate forever: although mostly solar-powered, the JWST needs a small amount of finite fuel to maintain its orbit and instruments.

4. Images Captured by JAMES WEBB

The JWST team has now announced the list of objects it has targeted with its first round of images. There will be five areas that are shown in these images:

4.1.Carina Nebula

Both one of the largest and brightest nebulae in the sky, the Carina Nebula is roughly 7600 light-years away.
The Carina Nebula houses some huge stars, several of which are much larger than the Sun.

4.2.WASP-96b

WASP-96b is a giant planet that is found outside of our solar system.
It is mostly composed of gas and is roughly 1150 light-years from Earth. It was discovered back in 2014.

4.3.Southern Ring Nebula

An expanding cloud of gas surrounded by a dying star, the Southern Ring Nebula is the perfect opportunity to test the James Webb Space Telescope's infrared images.
It is nearly half a light-year in diameter and is around 2000 light-years away from Earth.

4.4.Stephan's Quintet

Stephan's Quintet is located an amazing 290 million light-years away.
It was the first compact galaxy group ever discovered back in 1877 and will be the furthest image taken by the JWST.

4.5.SMACS 0723

SMACS 0723 is a patch of sky in the southern constellation of Volans. It has a massive cluster of galaxies in the foreground which act like a massive magnifying glass. This is because their incredible mass causes a noticeable curvature of the space-time around them, magnifying light from distant objects.

5. IN HIGH-RES: UNFOLDING MYSTERIES OF THE NIGHT SKY

James Webb space, with the release of its first five stunning images, has demonstrated an acute observational capacity and revealed aspects of the cosmos hitherto hidden from other telescopes.

As light travels with a velocity of about 3, 00,000 km per second, light from a distant object will take time to reach earth. Hence when we see a distant stellar object, we see it as if it were far back in time. To collect more light we need giant infrared telescopes.JWST is the biggest infrared telescope ever built.

The spectroscopic observation of JWST reveals that there is a considerable amount of water vapour in the WASP-96 b’s atmosphere. However, due to the blistering heat, WASP-96 is unlikely to host life.

On November 30, 1609, Galileo turned his telescope towards the night sky. Until then, scholars held that celestial objects were without any kind of blemish. Galileo showed that the moon had raters and mountains

All celestial objects, including stars, were thought to go around the earth. The telescope, by observing phases of Venus firmly established that planets go around the sun and not the Earth.

The Milky Way, a haze in the night that teemed with hundreds of stars, established that the cosmos is immense and beyond our imagination.

6.JSWT OBSERVATIONS

The deep field image of the SMACS 0723 cluster of galaxies has images that date back to times when the first stars were born. The images from Carina Nebula vividly show the birth of new stars.

In contrast, the southern Ring Nebula image details a dying star.

In Stephan’s quintet, the JWST has captured the cataclysmic cosmic collision of galaxies.

By analyzing the spectrum of the radiation from WASP-96 b, an exoplanet, the telescope has shown conclusively the presence of water vapour in the atmosphere of this hot, puffy gas giant planet orbiting a distant sun-like star.

With its sharp vision, more light collecting area and ability to see in the invisible infrared regions, the JWST is sure to expand our understanding of the cosmos.

7. PEERING BACK IN TIME

About 13.8 billion years ago, through the big bang, our Universe emerged. The first stars and galaxies were born around 300 million years after the Big Bang. To know more about the formation of these stars and galaxies, we do not need a time machine or time travel. As light travels with a velocity of about 3,00,000 km per second, light from a distant object will take time to reach us on Earth. Hence when we see a distant stellar object, we see it as if it were far back in time. Powerful telescopes are, therefore, like time machines.

However, since the objects far away are dim, we need giant telescopes to collect more light. Further light from distant objects is stretched out by the expansion of our universe, driving radiation from the visible range into the infrared. Therefore to look deep back into the early phases of the universe we need a giant infrared telescope, JWST is the biggest infrared telescope ever built.

8. CLUSTER OF GALAXIES

The SMACS0723 is a noted cluster of galaxies around 5.12 light years away Situated in the direction of the southern constellation of Volans, the image is as it appeared 4.6 billion years ago, about the same time when the sun and earth evolved.

SMACS 0723 galaxy cluster is massive, which as Einstein’s general relativity theory predicts, distorts the fabric of space-time

Like the refraction of a ray of light passing through a lens, the light from behind bends through the massive cluster. Due to this’ gravitational lensing’ effect, we notice that some galaxies appear distorted in an arc shape, some are split into multiple images, and some are magnified.

The kaleidoscope of colours in the image captured by the JWST‘s Mid-infrared Instrument (MIRI) is false colours (False colour refers to colour rendering methods used to display images which were recorded in the visible or non–visible parts of the electromagnetic spectrum, in colour)corresponding to a radiation wavelength.

Galaxies that appear blue in this image contain stars but very little dust. The cosmic objects enveloped by dust appear red. Objects rich in hydrocarbons and other chemical compounds are green.

9. WHERE STARS ARE BORN

Stars and star clusters are formed inside giant gas clouds. Typically the massive interstellar clouds where new stars are formed are huge with diameters of about 100 light-years and holding nearly six million solar masses.

There is enough material for making hundreds of stars out of this.

Nonetheless, the density of these clouds is just 100 atoms per cubic centimetre. The visible light is obscured by the thick dust that goes into the making of these stars and renders it opaque. Shrouded in thick dust clouds, these star-forming regions remained hidden from even powerful telescopes, until now.

One such stellar nursery booming with new stars is a giant interstellar gas cloud in our galaxy called NG 3324, dubbed cosmic cliff, located approximately7600 light years from Earth, and is home to many massive and young stars than our sun.

With the giant gas cloud condensing into new stars, this is an active star-forming region. Hot gas and dust emit infrared light. By steering its NIRcam and MIRI instruments into the highly dense dust clouds, the JWST has revealed rich details of this star formation region.

The striking image shows many exciting features in the innards of the star-forming regions. Hundreds of baby stars, previously invisible to telescopes, shine through the dust cloud. Thin gas pervades the space between the stars called the interstellar medium.

When the infant star begins to shine, it below away the interstellar matter. The region devoid of gas appears in the image in the shape of bubbles and cavities.

The mountains and valleys in the interstellar medium shaped by the radiation from the bubbling stars are visible, while the stars located in the centre of the bubble are off the frame.

Other phenomena that one sees in the image include ionized gas and hot dust wafting away due to radiation from young stars, casing turbulence and eddy and dust swirling in the surrounding gas. What appears as a golden comet in this image is jet outflows from the newborn stars.

Two Indian astronomers are slated to use the JWST data to study star formation.

Manoj Puravankara will be using the data obtained from Near Infrared Spectrograph (NIRSpec) and MIRI instruments to study the earliest phases of star formation, that is the protoplanetary disks- the birthplaces of planetary systems.

Jessy Jose, Assistant professor from the Department of Physics, IISER Tirupati will be part of an international collaboration to study the very massive, dense molecular cloud within the central molecule zone of our Milky Way to understand the young stellar objects within it

The NIRcam and MIRI instruments of JWST which broadly covers the wavelength range from 0.6 to 28 – micron meter will enable us to characterize the very early phase of star formation.

10. A STAR ON DEATHBED

The Eight Burst Nebula, also known as the southern Ring Nebula or NG 132 is a well-known planetary nebula in the constellation Vela, located approximately 2500 light years from Earth.

Planetary nebulae are gas shells formed from the cast-off outer layers of a dying star

Intermediate mass stars with a mass of 0.8 to eight times the mass of the sun end their lives with drama. They do not die in one big explosion but go through a cycle of fits and starts.

The dying star will expel its outer layer and expand, while simultaneously, its core will contract.

The contracting centre will once again start to emit energy, and the star will have a lease of life. The expelled shell is pushed by this radiation and expands in space like a ring around the central star

After some time the central star again shed its outré layer while the remaining core contracts.

Over time successive waves of expelled outer shells surround the central star–like concentric rings.

The remaining core of the star ultimately becomes a faint glowing white dwarf.

After trillion years they cool down and no longer shine, ultimately becoming black dwarfs. The near-infrared light is false-coloured blue, and the mid-infrared light is red in this impressive image by the JWST.

The consecutive waves of expelled shells can be seen clearly. In the central region, a redder star shining next to a bright blue one can be seen.

Astronomers knew that the southern Ring Nebula was a binary star system. For the first time, we can see the second star hidden behind the dust clouds .out the sun, an intermediate-mass star will undergo a similar fate.

11. COSMIC WALTZ

Situated in the direction of the constellation Pegasus, around 290 million light years away from Earth, is the clutch of five galaxies, each bound with the other called the Stephan’s Quintet.

Four of these close-knit galaxies are in a sort of dangerous waltz dance. Two of them are in process of merging.

Studying such cataclysmic galactic interactions will help us understand how these lead to star formation, evolution and central black holes in galaxies.

12. HUNT FOR THE EXTRATERRESTRIAL

The light from the central star will pass through the planet’s atmosphere when its edges are in the line of sight of the earth.The molecule present in the atmosphere will first absorb the light entering the atmosphere. Then it would be remitted

By comparing the star’s spectrum and the starlight passing through the planet’s atmosphere the astronomers can discern the molecular composition