NASA’s James Webb Space Telescope and Time Travel
NASA’s recent launch, the James Webb telescope is perhaps the most important and advanced innovation that humans have been able to send into outer space. It will allow us to penetrate through time and might even change the way humanity views the entire universe! Now how will that unfold? James Webb’s lens power is so high that it can see almost 13 billion years into the past which is nearly around the time the universe was just born. This will help us to view some of the earliest formed galaxies, stars and even planets. Another thing for which it is so revolutionary is that it can penetrate into the atmospheres of various planets and can find out about the chemical composition of those planets and whether there is any organic material present there. That may even help us to detect life on other planets. If the James Webb is successful in its research we may find the answers to a lot of unsolved mysteries so far in the history of humankind. But how does it even work? How can a mere telescope penetrate through time? To know about this there are certain scientific factors we have to take into consideration.
James Webb won’t be the first telescope to look into the past. Even before this, telescopes like the Hubble Space Telescope, Chandra and Kepler have looked into the history of outer space. How does this happen? Suppose there was an alien civilization in some galaxy 65 million light years away from us and they are quite a lot more advanced and intelligent species than we are. They have invented a telescope that can penetrate through all the cosmic dust and radiation and peek into our habitat. What will they see? Our advanced infrastructure? Human built monuments? Will they see us? The answer is no. They will surely be looking at our planet earth but instead of humans they will see dinosaurs and will see the earth as it was exactly 65 millions years ago from the present time. Quite shocking right?
This happens because the speed of light is finite. It travels at the speed of 300000 km/s. The distance light travels in a year is called 1 light year. So if a star is 1 light year away from us, we will be looking at the way it was 1 year ago when the light from the star that we are seeing now was emitted. Similarly a civilization 65 million light years away from us will be looking at us as we were 65 million years ago, that is when we did not exist! But there is one flaw with this phenomenon: the doppler effect (I have talked about this before in my previous articles, so if you are a regular reader you will get what I want to explain, so you can skip over). Let us take an example, when a car is travelling towards us, we observe its sound gradually increasing as it approaches us and again decreasing when it moves away from us. That is to say, the distance between the observer and the source affects the frequency and wavelength of sound; this also applies to light. When the distance between the object that emits light and the observer increases, then the wavelength and frequency of the light increases. This is explained by the General Theory Of Relativity. According to Einstein’s revolutionary theory, our universe is expanding by the repulsive force of dark energy that makes up more than 60% of our universe. Due to this expansion, the distance between two objects suspended in space-time across the universe is increasing at a level above the critical rate*. Because of this effect, light travelling from a faraway object shifts to a much longer wavelength like infrared, radio, microwave etc. which cannot be detected easily. The light that was emitted after the Big Bang has now travelled about 14 billion years across the universe and is known as the cosmic microwave background radiation as was discovered by Penzias and Wilson.
Now that we have understood this time travelling phenomena, let us see how the telescope functions. The telescope is lightweight compared to its fellow companions like Hubble or Kepler but much larger and wider. It is like a hexagon shaped origami artwork that will unfold in outer space. The telescope has 18 hexagonal mirror segments. These segments will collect light waves from across the universe belonging to all wavelengths, from the visible spectrum to the infrared ones. These light waves will get collected at the centre of the telescope where there is a camera that accesses them. Beneath the camera, there are tools engineered that will help detect and make images out of the radiation received.
Moreover, the James Webb Telescope uses a new technology called the Microshutter system. This is made up of 250,000 shutters that open and close. They are used to block out the extra amounts of light so that the telescope can focus on vital objects at once. For example, in an urban area, we see a few stars across the night sky whereas, in a rural area we see plenty. This is because light pollution in cities is much higher than in the countryside. This way the telescope’s shutters block out extra light and therefore it can even focus on the most faintly lit objects as explained by the doppler effect. There is a lot of light in outer space and so the telescope, in order to focus, has to keep moving hastily. This is guided by its Fine Guidance Sensor. Now there arises another issue. Outer space doesn’t only have huge amounts of light but also dust clouds created by supernova explosions or existing nebulae etc. Normal infrared rays are not able to penetrate these clouds. Here another important tool of the telescope, MIRI comes in handy. MIRI is constructed in such a way that it can detect and make out the infrared radiation of really long wavelengths that can actually penetrate dust clouds.
The James Webb is currently unfolding its future in outer space and scientists who have spent decades of their lives in developing it are in deep anticipation of its safe insertion in the proper orbit. But it is not only the scientists at present whose hard work is about to be repaid. Since time immemorial, people have indulged themselves in solving the mysteries of our universe. From hunters and foragers making out patterns in the night sky to modern humans sending advanced tools into outer space, we have come a long way. If this telescope is able to penetrate far into 13 billions years in the past, it will see the very beginning of an era from where the universe and we as we know today came into being. That will indeed be one of the most wonderful feats of human history.
As Carl Sagan once said, “Somewhere, something incredible is waiting to be known”.
