The James Webb Space Telescope

Written 7/24/2022

How powerful is the James Webb Space Telescope? Well for starters, we already know that the James Webb is an infrared telescope. Basically meaning that it can easily look at objects that are billions of lightyears away. All infrared space telescopes work fundamentally the same way. However, the James Webb in particular, has numerous mirrors - the most obvious is the gigantic 21 foot primary optic, and the slightly smaller, 4 foot secondary optic. The main detail that sets the James Webb from the others is the multi-panel primary mirror that is mounted on the very top of the telescope.

This giant mirror reflects all of the light it receives into the smaller mirror just in front which reflects the light into a rectangular shaped tertiary mirror, in which the light is sent into a series of reflections before being shown to the science instruments behind it. The main reason this works is - because all the light once projected onto the primary panel is reflected into smaller and smaller mirrors, the light is being concentrated into a smaller vision before going through the shape of the lens (which enlarges the concentrated light) you see it through, creating the image of what the telescope sees. This image can change depending on the size of the panels. The larger the panel, usually the more it can reflect and this expands the amount of visible light a telescope is able to capture on the light spectrum.

In the case of the James Webb, it is capable of seeing nearly 60% of the entire infrared light range, or just around any wavelength between 600 to 28,000 Nanometers (NM). Which absolutely destroys Hubble's 90 to 2,500 NM range - or just 20% of ultraviolet light and 4% of infrared light. But despite having such a small range, Hubble can capture visible light, something James Webb cannot do - as it was constructed to observe almost exclusively in infrared.

Each telescope has their own pros and cons, but for now I will primarily look at distance, rather, how far a telescope can see. And for that place goes to the James Webb Space Telescope, crowned the most powerful space telescope to exist today. And if you are curious on where other telescope stand besides James Webb, here is the data I’ve gathered based on the furthest object or area in space away from earth they have seen:

Note: For those still confused about lightyears, lightyears measure how far light travels in a year, meaning that the term lightyear can also be translated into a year. For example, if we look at something 10 light years away, the light we see is 10 years old because it took 10 years to travel to us. So whenever someone says something is a lightyear away, it can also mean that you are looking back in time - at something a year old. (Also creating the saying, “space is a time machine.”)

0. Age of the Universe is 13.7 Billion years old

James Webb - 13.6 Billion lightyears - Able to see the oldest and farthest away stars, created at the dawn of time. They probably don’t even exist today as we are only looking at what looked light 13.6 billion years ago.

Hubble - 13 Billion lightyears - You can’t see it, as we aged and lived alongside it, but this is around the time the Milky Way was first made. Some of the earliest and oldest of stars made when the galaxy first formed are still with us today.

Spitzer - ~12 Billion light years - Can look at the universe in its early age of just 600 million years.