James Webb Space Telescope — a marvel of science, design, and AI
A 10B dollar time machine
Based on reviews from my readers, I am experimenting with a new format for this article. I will try to organize the whole content in QnA format so that the content becomes even more digestible and faster to read based on preference. Let me start with what is JWST in the first place!
What is JWST?
A 10-billion-dollar time machine that took 20 years to build. I say it is a time machine because it shows the images of galaxies and stars that existed ~13B light years ago.
How above statement is possible?
The lights which have been traveling for 13 billion years have stretched out and become infrared (IR) by the time it reaches us. This happens by the virtue of Einstein's theory i.e. space is curved and hence time is bent. We say time is bent since the light takes more time than it should have taken (due to stretching) and hence, we see the objects delayed. This telescope collects those infrared (IR) lights and translates them into images using the heat signatures of the IR rays.
Why there is so much fuss about it?
By studying the properties of light emitted by an object, we can tell the composition of the object. This can lead to the study of those galaxies that were formed around a 13 billion years ago and are approx 13 billion years away. If those properties match with what we have known about the earth, it means those planets have a life now similar to earth. Though we cannot visit the place for sure but isn’t this already a big deal that we are sure that life exists in other places!
Why there was a need for it?
Now if it can tell about those far planets, it can very precisely tell about the nearby galaxies and planets and fast forward our search for extraterrestrial life or at least a place that has similar features and at the same distance from its star to sustain life. If that happens, we will have the option to expand our species.
How it is different from the Hubble space telescope?
Hubble can be maintained every now and then since it is just 547 km from the earth whereas JWST is 170 million km away, hence scientists have just one shot at its launch and setting up it properly. In fact, a small accident led to one of the mirrors being little dented but scientists have to live with it now. The benefit is, that since it is million miles away, we can easily cut through a huge chunk of gases and dense substances that populate our solar system near earth.
Sounds interesting now, tell me more in-depth!
- It can study more than 250k objects at one and collect lights from them simultaneously for 100 hours since that is the threshold required for any light to make sense out of it and deduce some results.
- But the heat from that equipment (called MIRI) can interfere with the light collected and hence a cryocooler was built to keep MIRI below -266 degree Celsius (i.e. below - 447 degrees Fahrenheit).
- Moreover, a 5-layer shield called sunshield made up of Kapton was built to shield the system from the external temperature of sun and moon. And then for the same reason, it had to be 1.5 million km from earth (mars is 170 million km) as compared to Hubble which is only 547 km
- It will be located at a special location where gravitation forces allow the object to a fixed position relative to earth. It is called the Lagrangian point (L2)
- Fun fact, it can detect the heat signatures of a bumble bee on the moon
What is next?
Since there are multiple investments in building this start-of-the-art flying object, its time in space, which is around 20 years, will be used by multiple research organizations to juice out all kinds of possible information for the benefit of humanity. This is THE epitome of telescopy as of now but it will definitely keep inspiring multiple generations to keep building something which is thousand times better than before and add galaxies to our “known neighborhood”.