The JWST — Everything you need to know
Introduction
If you’ve been watching the news lately, you’ve likely come across something known as the “James Web Space Telescope”, or lovingly referred to as the “JWST” by Astronomers. The 10 billion dollar time machine (You’ll understand why I call it that if you read on) is a byproduct of decades of blood, sweat, and tears by engineers at NASA, the ESA (Europian Space Agency), and the CSA (Canadian Space Agency). It is extremely exciting for various reasons why I will delve into and can potentially be a key player in revolutionary discoveries that will take place (hopefully) in the near future.
What is the JWST?
The JWST is NASA’s newest space telescope, they received help from the ESA, and CSA during development and was launched on the 25th of December, 2021, on board an Ariane-5 rocket. Named after James E. Webb, the director of NASA in the sixties, the telescope is set to take over the reigns of the Hubble Telescope.
The JWST is a reflective telescope (Check out my post on the different types of telescopes and how they work). What are these big yellow hexagons, you ask? These are actually small mirror segments that combine to form the main primary mirror. These segments are made out of beryllium. The fourth element of the periodic table was picked because of its desirable properties, it is not magnetic, and is a good conductor of heat (This is especially important considering that it plans on collecting infrared light), and electricity.
What is the point of the JWST?
The JWST is a telescope so powerful that it can capture light from such large distances that it allows us to peer into the past. Confusing, right? Well, it takes light about 8 minutes to reach the Earth from the Sun. This means that when you look up at the Sun, you’re actually only seeing the Sun as it was 8 minutes ago. The JWST is practically a time machine that allows us to see up to 10⁸ (100 million) years after the big bang. We can see stars and galaxies in their infancy, allowing us to study their lifecycles in greater detail. The JWST can also look for exoplanets (planets outside the solar system), in the hopes that we can find one that can sustain humans, and other organisms.
Why did it take so long to develop?
The telescope is nothing short of an engineering marvel. Remember those yellow mirror segments? There are exactly 18 of them on the entire telescope, each with a diameter of 1.3 m. They have the ability to fold, and unfold, which is exactly how it got to space. On the Ariane-5, the entire mirror was folded up, and it unfolded successfully, yesterday, on the 8th of January, 2022. Actuators are carefully fitted on the back of each mirror segment can slightly move the segment up, down, left, and right in order to align the different segments in space to optimise light capture.
The telescope also has to be kept extremely cold. This is so that the infrared light that the telescope captures does not get messed up by the infrared light the telescope emits. The mirrors have to be kept at around -220⁰ C, and so, is fitted with multiple sunshields to protect it from the heat of the Sun. The sunshield is extremely large and covered with a layer of Kapton, a type of plastic which when coated in aluminium (increases the reflectivity of the sunshield), allows the sunshield to effectively protect the JWST. Each layer of Kapton are fractions of a milimeter with the thickest layer being around 0.05 milimetres. This called for extremely precise measurements, calculations, and necessitated handling of the highest care.
The team of engineers also had to deal with several challenges along the way such as hurricanes, earthquakes, and other natural disasters. If there was even a small defect on one mirror segment, it would have to be built from scratch. The entire telescope has to be kept very clean as well; which is why if you search up images of the JWST, you will likely see people donning these HAZMAT suit type outfits to prevent any form of dust/debris landing on the telescope.
The telescope’s primary mirror is much larger than that of the Hubble’s.
This significant increase in size allows for more light to be captured, allowing us to see further in the past. Despite this increase in size, the JWST is still 100+kg lighter than the Hubble mirror.
The telescope is set to travel 1.5 million km from Earth (3000 times the distance Hubble travelled) to a point known as L2 or Lagrange Point 2. A Lagrange point is a point between two celestial objects in which a smaller object is unaffected by the gravitational forces exerted by the two celestial objects and stays put. There are 5 Lagrange points each named L1 to L5. L2 is the best point for the Earth and the Sun because it provides the best view of deep space, allowing us to gather as much information as possible.
During launch, there are several ways this billion dollar project can go wrong. The sunshield is held up by a hundred pins which have to be released in the right order for it to open correctly, facilitating the unfolding of the mirror segment, if it was done incorrectly, 25 years of hard labour would have gone down the drain. Luckily, the launch did not have any complications.
What’s next for the JWST?
The mirrors have successfully unfolded as of the 8th of January, 2022. JWST will reach L2 by around the end of January and will take up to half a year for operations to start, we have to wait 6 whole months before we get the first image :/
The telescope is said to be operational for about 5 years but its launch was so successful that NASA is estimating it to be active for around 10 years (The limiting factor here is fuel).
The JWST is a scientific, and engineering miracle. I can’t even fully imagine all the countless discoveries that will take place, theories that can be proved, and information that can be unearthed by the telescope. This telescope will literally allow us to learn about the beginning of humanity. From the big bang to planet formation, we are on the brink of the golden era of science.
Here is an amazing video which covers every aspect of the JWST in detail and here is the video of the historic launch
