Why You Should Care About The James Webb Space Telescope, Even If You’re Not A Science Nerd


**I originally wrote this in 2015 for another website which has since closed down, so I thought I'd republish it here - Enjoy!**

We’ve all heard of the Hubble Space Telescope, which is celebrating its 25th anniversary this year, but its successor – the James Webb Space Telescope - is due to be launched in 2018, and it’s very exciting indeed.

Goodbye Hubble :’(

Even the most un-science-y of us can appreciate the beauty of the images that Hubble has been beaming back to Earth since its launch on April 24th 1990, including the famous Pillars of Creation:


And the Hubble Ultra Deep Field:


The above image is an 11-day exposure, taken whilst Hubble was pointed at a supposedly ‘empty’ patch of space. What you see are 10,000 of the most distant galaxies to have ever been photographed by an optical telescope. Not stars, galaxies. Each one containing billions of stars and solar systems just like ours. It’s truly mind blowing.

But Hubble won’t last forever and NASA has sent crews up into space a number of times to make repairs and upgrades, which is no longer cost effective. Not to mention that our technology has improved vastly in the last 25 years, making a new telescope a better long term option.

But don’t be too sad; we’ve got a few years left before Hubble’s successor is launched, and the upgrade is definitely worth it.

Bigger is Better

Well, in the telescope world at least. Telescopes use mirrors to gather light and, as a general rule, the bigger the mirror, the better the images. Hubble’s 2.4 metre wide mirror is not to be sniffed at by those of us on Earth, but the JWST will have a mirror with a surface area of 4.5 metres, giving it about 7 times more light-collecting power than Hubble.


Image from: "JWST-HST-primary-mirrors" by Bobarino - Own work based on File:JWST-HST-primary-mirrors.jpg a NASA public domain image. Licensed under CC BY-SA 3.0 via Wikimedia Commons.

Size isn’t the only factor though, as even the best telescope in the world is useless if it can’t actually see the thing it wants to look at. Fortunately, the JWST has another trick up its sleeve: its orbit.

Hubble orbits Earth at a distance of around 570 km, but the JWST will instead orbit the sun at about 1.5 million kilometres from Earth. This sounds even more impressive when you realise that the moon is only 384,500km away! That gives the JWST a view even the fanciest London flats can’t compete with.

But wait, there’s more! The JWST will observe the universe mostly in infrared, whilst Hubble primarily uses the ultra-violet and visible parts of the light spectrum.

That means that Hubble sees a bit more than the human eye can but can’t look into dark parts of space, like inside or behind dust clouds. Infrared light, though, can penetrate this dust and the JWST can pick this up, giving us a much better view of things like interstellar nurseries, where stars are born inside huge murky nebulas. Put these three factors together, and you’ve got one impressive telescope. One that will be able to take larger, clearer photos, and help us to see further and into much darker parts of space than we ever have before. See, I told you it was exciting.

So, what will the JWST be looking for in these dark nooks and crannies?

The Search for Life

The JWST won’t be looking for aliens as such, but the planets that might harbour them. Exoplanets to be exact.

It can do this by using the ‘transit’ method; watching a star to see if it dims slightly at regular intervals, indicating that a planet is passing in front of it.


The JWST will also use spectroscopy to determine the atmosphere of the exoplanets it finds. Spectroscopy  is the science of measuring the intensity of light at different wavelengths. Put simply, this means that if a planet’s atmosphere contains methane, water, or something else that might indicate life, then the JWST will be able to tell based on where about on the spectra the readings fall.

This sounds obscure, but from this data, the JWST will be able to determine the colour, seasons, weather and rotation of an exoplanet, as well the likelihood of any vegetation or alien life.

Our Solar System

If a potential visit from E.T doesn’t interest you, then the JWST will also be looking closer to home. It will look towards Mars to help us gain a deeper understanding of our red planet’s atmosphere as well as verifying the data from the Mars Rovers.

The JWST will also be analysing the gas giants to give us a better picture of the weather systems on Saturn and Jupiter and helping us learn more about what minerals make up the asteroids in our asteroid belt.


Still not impressed?

Well, there’s just no pleasing some people, but you might like to know that development of the JWST has significantly advanced a number of technologies that are useful down here on Earth. The most consumer friendly of these is wavefront sensing technology, which helps doctors to measure eyes, diagnose various eye conditions and improve surgery. Four patents have been issued as a direct result of the JWST, and the improvements made in the last few years mean we can now get detailed information about the shape of our eyes in seconds rather than hours.

Hopefully, after reading this, you’re suitably bowled over by the James Webb Space Telescope. There’s loads more to learn on NASA’s official JWST site, and you can even watch a live webcam of it being built.

But until it’s finished, we can continue to enjoy Hubble’s beautiful images and admire all the amazing discoveries it has made over the last 25 years. After all, without Hubble, there would be no James Webb Space Telescope.