The James Webb Space Telescope: A time machine

By: Reed Morris

Image taken from: JWST
Adriana Manrique Gutierrez, NASA Animator

The James Webb Space Telescope (JWST), is the flagship observatory for NASA’s next generation of space telescopes. The project has been in progress for years and has cost around 10 billion dollars to complete. Many people refer to it as “The new Hubble”; while this is partially true, Hubble and the JWST have very different missions, and operational capabilities.

The two most important differences between the two observatories are their mirror sizes, and the imaging equipment on board. The size of the mirrors are very important as the image quality and range capabilities of telescopes directly rely on the size of their mirrors. Hubble is equipped with a mirror 2.4 meters or 7.8’ in diameter, whereas the JWST has a mirror diameter of 6.5 meters or 21.3’, a massive leap forward for space telescope capabilities.

Image taken from: JWST

The other main difference between the two is their individual operation capabilities. Hubble has cameras that focus mostly on the visible light range with minimal ultraviolet and infrared capabilities. The JWST however has extreme infrared capabilities. This is where the time machine nickname comes from. Infrared imaging in space exploration is extremely important because of the way that the expansion of the universe affects light. The farther away an object is from an observer, the greater the expansion and stretching of the universe affect the wavelength of light. As space stretches, so does the wavelength of light, redshifting the waves from visible light onto the infrared spectrum. Having high infrared capabilities is necessary to image events that took place an incomprehensible amount of time in the past, over similarly incomprehensible distances.

The above image compares the light detecting capabilities of the two telescopes, with their respective nanometer values.
Image taken from: JWST

The James Webb Space Telescope is a monumental step forward in astronomy. It will let us peer billions of years into the past to witness the formation of the first galaxies. It will also be used to search for exoplanets that could harbor life, and get beautiful images of the vast expanses of space. The galaxy formations that the JWST will be observing are events that took place possibly only 100 million years after the creation of the universe, the Big Bang. While Hubble was, and still is a hugely important tool for space exploration, the JWST ushers in a new era of deep space imaging, and is a launching pad for humanity’s better understanding of the creation of galaxies and the universe as a whole.

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