How James Webb Space Telescope different from other telescope
The primary reason of placing telescope outside earth's atmosphere is to explore the galaxy in more depth. It also helps in getting more sharp images of planet, stars and other phenomenon taking place in the range of light years. The basic mechanism behind the recently launched James Webb Space Telescope, which works by reflecting the images of stars and planets can be understood better by taking example of time taken by light to reach the surface of earth. It took 8.3 minutes for photons emitted from the surface of sun to reach human eyes, which means that even if the sun vanishes in the mid-time i.e. before 8 minutes, we will be able to see the sun till the end of 8.3 minutes. In the same way the images of stars that we see today are the actual images that exist about billions light years ago.