How the James Webb Telescope will take pictures of the past

The James Webb Telescope has departed to look into the past. To take pictures of the past.

I said in a post a few days ago that I will write another day about how to take pictures of the past. I want to write today.

how-james-webb-telescope-will-take-pictures-of-past


It is unknown at this time what he will do after leaving the post.


He will take pictures of thirteen and a half billion years ago or even earlier. Pictures from hundreds of millions of years ago. Pictures from a billion years ago. Pictures from five billion years ago. One hundred billion years ago. Pictures fifty million years ago. Pictures from tens of millions of years ago. Pictures a million years ago. Pictures from five million years ago. Pictures from a million years ago. Pictures from ten years ago. Picture from a year ago. In a word, pictures of different times of the past. From the past to the present, about fourteen billion years ago.


How will he take so many previous pictures? Is the picture of the past floating in the air? The answer to this question is simply to say that the main purpose of my post today.


The James Webb Telescope has a large round mirror. You may have seen it in the picture. If the light of something falls on that mirror, he will capture that light like a camera. The diameter will become the picture. It's so simple. That's all we see in the case of our mobile camera. The lens of the camera also has a mirror. The light from the object we want to photograph falls on the camera mirror. And the camera processes it a little and captures it. The diameter becomes the picture.


The same thing happened with the James Webb Telescope. Light will come from far away and fall on his mirror. And he will process that light and capture it. Then send it to us. We will get the image of that distant thing or that distant state in the form of pictures. Simple.


What remains difficult is the picture of the past. That too is a long time ago. How to pick?


It's easy too. Easy to understand.

We see the sun. Because light comes from the sun and falls on our eyes. We see the moon because the light of the sun falls on the moon and falls on our eyes. You see me when I stand in front of you. Because sunlight or any light falls on my body. Then it fixes and falls on your eyes.


It takes time for the light to come on. It takes more than a second for light to come from the moon. It takes more than eight minutes for light to come from the sun. It takes more than four years for light to come from the nearest star. It took us more than fifty thousand years for light to reach us from the last star in our galaxy.


There are galaxies far, far away from us. Their light is also reaching us. They are far away. Far away Which is so far away that it takes five hundred billion years for light to come from there. One thousand crore years. Thirteen and a half billion years.


If we can capture those lights with the camera, then pictures of the past will be taken.


This universe started from the Big Bang. About fourteen billion years ago today (13.6 billion years). Then for millions of years, the universe was dark. Then the light begins to spread (details will be written later in a post). Then the stars are formed. The galaxy is formed. Those stars are no longer alive. Is dead. Has become a black hole.


But the light that was sent from those stars is floating in the universe. The light from the stars that formed in this region of ours has gone to the other end of the visible universe. And the stars that were formed at that end, the light is reaching us here.


We need to capture those lights on camera now. But the problem is, the light from far away has faded. Their wavelengths have become longer. Why that happened is another story. That is the subject of Einstein's general relativity (I will explain another day).


Those faint lights can't catch our Hubble Telescope. James Webb can. He needs to keep the telescope mirror very cold to catch the light. Very cold Need to cool minus 220 degrees. To keep it so cold, James Webb had to be sent a million miles away. So that with a shield he can always be protected from sunlight. That place a million miles away is perfect for that (how to write it another day).


I think I have strayed a little from what I was saying. Let's get back to the basics.


The universe is all around us. Up and down, right and left, all around. Light comes to us from all directions. There are stars, galaxies on all sides. Which is near, which is far. Far away James Webb will take pictures everywhere. Even those near and far.


If you take a picture of a galaxy that is (was) a billion light-years away, it will be a scene from a billion years ago. And if you take a picture of what was a million light-years away, it will be a picture of a million years ago.


It takes time for the light to come on. This is the essence of the word. It takes 6 minutes and 20 seconds for light to come from the sun. So now if you take a picture of the sun, it will be a picture of the sun 8 minutes and 20 seconds ago.

Stay tuned today. I will write more about the various aspects of James Webb in the future, I hope. Forgive the mistake. Pray for me.

-

How the James Webb Telescope will take pictures of the past

Author:

Habibullah bin Abdul Haq.

Writing date: 15/01/2022


Previous Post
No Comment
Add Comment
comment url