{"id":35958,"date":"2022-08-27T08:27:05","date_gmt":"2022-08-27T08:27:05","guid":{"rendered":"https:\/\/www.skyatnightmagazine.com\/?p=111401"},"modified":"2022-08-27T08:56:14","modified_gmt":"2022-08-27T08:56:14","slug":"4-questions-james-webb-space-telescope-is-poised-to-answer","status":"publish","type":"rss_feed","link":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/rss_feed\/4-questions-james-webb-space-telescope-is-poised-to-answer\/","title":{"rendered":"4 questions James Webb Space Telescope is poised to answer"},"content":{"rendered":"

<\/p>

By Colin Stuart\n \t\t<\/p>

Published: Saturday, 27 August 2022 at 12:00 am<\/p>

\n\n

It\u2019s safe to say that the James Webb Space Telescope hasn\u2019t disappointed.<\/p>\n

The hype surrounding the largest telescope we\u2019ve ever launched into space was big, and decades-long, but as the latest James Webb Space Telescope images<\/a> show, its view of the Universe is groundbreaking.<\/p>\n

\"""\"<\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/picture><\/div>
The Carina Nebula, James Webb Space Telescope, July 2022. Credit: NASA, ESA, CSA, STScI<\/span><\/figcaption><\/div>\n

But clearly there\u2019s more to JWST than just beautiful images. What sort of data will astronomers receive as the Webb Telescope continues its journey peering deep into our Universe?<\/p>\n

What questions will the James Webb Space Telescope<\/a> answer along the way? What cosmic mysteries will it solve?<\/p>\n

Astronomers, astrophysicists, planetary scientists and exoplanet hunters already have multiple questions they\u2019re hoping JWST will be able to answer, and as the months and years go by, many more mysteries will surely raise their head.<\/p>\n

Here are 4 questions astronomers are hoping JWST will be able to address over the coming decades.<\/p>\n

4 questions for James Webb Space Telescope to answer<\/strong><\/h2>\n

What do the first stars look like?<\/strong><\/h3>\n
\"""\"<\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/picture><\/div>
JWST has found the oldest galaxies ever seen, like GLASS-z13 (above), 13.4 billion lightyears away. Credits: GLASS-z13 (Naidu et al. 2022. Castellano et al. 2022<\/span><\/figcaption><\/div>\n

Astronomers are always looking back into the past. That\u2019s because it takes time for light to travel across the Universe.<\/p>\n

We don\u2019t see things as they are when the light arrives here, but as they were<\/i><\/span> when the light first departed. For distant galaxies<\/a>, the delay is millions and even billions of years.<\/p>\n

When we look at the night sky, we are essentially looking back in time<\/a>.<\/p>\n

So very distant galaxies were also some of the first galaxies to form in the Universe.<\/p>\n

The Hubble Space Telescope<\/a> revolutionised this area of research, finding thousands of distant galaxies in a patch of sky so tiny that it could be covered by a grain of sand held at arm\u2019s length.\u00a0<\/span><\/p>\n

\"""\"<\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/picture><\/div>
Hubble\u2019s eXtreme Deep Field. (Credit: NASA; ESA; G. Illingworth, D. Magee, and P. Oesch, University of California, Santa Cruz; R. Bouwens, Leiden University; and the HUDF09 Team)<\/span><\/figcaption><\/div>\n

The light from the most distant galaxy observed before JWST \u2013 HD1 \u2013 took a staggering 13.1 billion years to reach Earth.<\/p>\n

Astronomers are peering back to a time just 700 million years after the Big Bang<\/a>.<\/p>\n

Yet they want to look back even further to when the very first stars and galaxies appeared, estimated to be 100\u2013200 million years after the Big Bang.<\/p>\n

They\u2019re hunting the first light that lit up the so-called cosmic dark ages.\u00a0<\/span><\/p>\n

Hubble just isn\u2019t up to that task. You need an entirely different kind of telescope.<\/p>\n

Enter JWST, which gathers infrared<\/a> light instead of the visible light to which our eyes, and Hubble, are sensitive.<\/p>\n

Infrared light is able to penetrate the dust that can sometimes block our view of distant galaxies.<\/p>\n

\"""\"<\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/picture><\/div>
Webb Deep Field, James Webb Space Telescope, July 2022. Credit: NASA, ESA, CSA, STScI<\/span><\/figcaption><\/div>\n

For the very first galaxies, there\u2019s an even more fundamental problem with observing in visible light.<\/p>\n

The Universe has been expanding ever since its birth in the Big Bang. Any light travelling through the expanding Universe also gets stretched \u2013 or red shifted<\/a> \u2013 along the way.<\/p>\n

The light from the earliest stars and galaxies has been stretched so much that it\u2019s now slipped out of the visible spectrum and into the infrared.<\/p>\n

\"""\"<\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/picture><\/div>
A NASA image showing how wavelengths of light are stretched \u2013 or redshifted \u2013 as the Universe expands. Credit: NASA\/JPL-Caltech\/\/R. Hurt (Caltech-IPAC)<\/span><\/figcaption><\/div>\n

Now, for the first time, we\u2019ll be able to see it.<\/p>\n

\u201cIt\u2019s a chance for scientists to find out what typical galaxies were like in the very early Universe and maybe even find evidence of the very first stars ever formed,\u201d says Dr Emma Curtis-Lake, STFC Webb Fellow at the University of Hertfordshire.<\/p>\n

How do galaxies form?<\/span><\/strong><\/h3>\n
\"""\"<\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/picture><\/div>
Galaxy NGC 3256, about 100 million lightyears away, formed as a result of a merger of two galaxies. Credit: ESA\/Hubble, NASA<\/span><\/figcaption><\/div>\n

We live in the Milky Way<\/a> galaxy \u2013 a vast stellar metropolis containing up to 400 billion stars.<\/p>\n

In turn there are up to two trillion other galaxies in the Universe. But how are these vast structures made?<\/p>\n

Most astronomers tend to favour a so-called \u2018bottom-up\u2019 approach in which a galaxy forms from a series of mergers involving smaller groups of stars.<\/p>\n

Yet it is far from clear exactly how this process plays out. Thankfully, JWST can help.<\/p>\n

One of the early images from JWST depicts Stephan\u2019s Quintet, a collection of five galaxies, four of which are interacting with one another.<\/p>\n

\"""\"<\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/picture><\/div>
Stephan\u2019s Quintet, James Webb Space Telescope, July 2022. Credit: NASA, ESA, CSA, STScI<\/span><\/figcaption><\/div>\n

It shows us that a gravitational dance is underway as dust, gas and stars pirouette, pulled around by each other\u2019s gravity.<\/p>\n

One of the galaxies \u2013 NGC 7318B \u2013 is producing huge shockwaves as it careers through the cluster.<\/p>\n

While the four interacting galaxies are relatively close to us at just under 300 million lightyears, studying them will help astronomers understand what they\u2019re looking at when they turn JWST towards more distant galaxies.<\/p>\n

One instrument aboard JWST is particularly well suited to this endeavour: the Near-Infrared Spectrograph (NIRSpec).<\/p>\n

\"""\"<\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/picture><\/div>
A MIRI version of Stephan\u2019s Quintet, captured by the James Webb Space Telescope. Credit: NASA, ESA, CSA, and STScI<\/span><\/figcaption><\/div>\n

Astronomers have already pointed it towards the supermassive black hole in the centre of one of four interacting galaxies in Stephan\u2019s Quintet \u2013 NGC 7319.<\/p>\n

Black holes<\/a> are thought to play a significant role in galactic evolution.<\/p>\n

The one in NGC 7319 has a mass equal to 24 million Suns, a number so big that it could only have formed by the mergers of lots of smaller black holes.\u00a0<\/span><\/p>\n

The instrument has also been deployed further afield.<\/p>\n

\u201cMy favourite moment [from the first JWST data] was when they revealed the image showing the NIRSpec spectrum of a galaxy over 13 billion lightyears away,\u201d says Curtis-Lake.<\/p>\n

\u201cI\u2019ve been impatient to find out how NIRSpec performs, and I can\u2019t wait to get my hands on it and test our models for my own research,\u201d she says.<\/p>\n

NIRSpec can simultaneously observe hundreds of galaxies at once, looking for evidence that mergers are taking place.<\/p>\n

How are stars and planets born?<\/strong><\/h3>\n
\"""\"<\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/picture><\/div>
The penetrative power of JWST\u2019s infrared is starkly revealed in this comparison of the star nursery in the Carina Nebula (left) with the image taken by the Hubble Space Telescope in 2008 (right). Credit: NASA\/ESA and The Hubble Heritage Team (STScI\/AURA)<\/span><\/figcaption><\/div>\n

The modern world offers people many ways to look back on what we were like as children. It isn\u2019t so easy with stars<\/a>.<\/p>\n

Our Sun is in its middle age at 4.6 billion years old, but astronomers have found some stars that are just one million years old \u2013 that\u2019s the equivalent of being a 3.5-day-old baby in human terms.<\/p>\n

Among the first images to be returned by JWST is a stunning look at the Carina Nebula, a cloud of gas and dust where hot young stars are bursting into life.<\/p>\n

These stellar infants are enshrouded by dust, which obscures the view that visible light telescopes such as Hubble can see, but which JWST pierces straight through.<\/p>\n

The infrared reveals hidden stars, allowing astronomers to see how their radiation carves through the surrounding gas.<\/p>\n

\"""\"<\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/picture><\/div>
An image of a protoplanetary disc around star HL Tauri. The dark rings could indicate newly-forming planets in orbit, pushing aside dust as they go. Credit: ALMA (ESO\/NAOJ\/NRAO)<\/span><\/figcaption><\/div>\n

The telescope will also be able to look at the planet-forming regions around stars. The outer parts of these protoplanetary discs have been studied before using radio telescopes such as the Atacama Large Millimeter Array (ALMA) in Chile (see image above).<\/p>\n

However, JWST\u2019s greater resolution will mean it can peer into the inner part of the disc where rocky Earth-like exoplanets<\/a> may be forming.<\/p>\n

JWST will measure the different types of molecules present in the inner disc such as water, carbon dioxide and methane \u2013 all associated with life in some way.<\/p>\n

If, for example, water is already present in and around newborn rocky planets then that has promising implications for our chances of finding water worlds elsewhere in the Universe.<\/p>\n

\"""\"<\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/picture><\/div>
An artist\u2019s concept showing how exoplanet 55 Cancri e compares with Earth. 55 Cancri e has a mass 7.8 times and a radius just over twice that of our own planet, making it a \u2018super Earth\u2019. Credit: NASA\/JPL-Caltech\/R. Hurt (SSC)<\/span><\/figcaption><\/div>\n

Astronomers have already been surprised by the variety of distant planets they\u2019ve found to date. Many stars are orbited by so-called super-Earths and mini-Neptunes \u2013 worlds partway in size between the Solar System\u2019s rocky and gas planets.<\/p>\n

They seem to be the most common type of planet in the Universe and yet there is none in our own Solar System.<\/p>\n

JWST could help us learn what these planets look like and how they come about.<\/p>\n

Many of these observations can only be made in the infrared, which is absorbed by Earth\u2019s atmosphere.<\/p>\n

It\u2019s why these measurements require a space-based telescope.<\/p>\n

JWST is also positioned 1.5 million kilometres away from Earth to avoid contamination from the infrared energy emitted by Earth itself, giving it the clear view it needs to pick up such miniscule detail from lightyears away.<\/p>\n

Is there another Earth out there?<\/span><\/strong><\/h3>\n
\"""\"<\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/picture><\/div>
An artist\u2019s impression of Earth-like exoplanet Kepler-186f. Credit: NASA<\/span><\/figcaption><\/div>\n

Perhaps the biggest question it\u2019s possible to ask about the Universe is: \u2018Are we alone?\u2019.<\/p>\n

JWST should allow us to make a giant leap forward in finding the answer.<\/p>\n

So far we\u2019ve confirmed over 5,000 exoplanets<\/a> \u2013 planets in other solar systems.<\/p>\n

The bulk have been found using a technique called the transit method.<\/p>\n

Although distant planets are too small and dim to be seen directly, we do see a temporary drop in the brightness of their host stars when a planet passes in front of them (an event called a transit).\u00a0<\/span><\/p>\n

\"""\"<\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/picture><\/div>
Transit photometry reveals exoplanets by observing periodic dimming of the star\u2019s light.<\/span><\/figcaption><\/div>\n

It\u2019s a change in brightness of less than 1%, but it holds a wealth of information.<\/p>\n

As the planet passes between us and the star, some of the star\u2019s light filters through the planet\u2019s atmosphere before continuing on towards Earth.<\/p>\n

Different chemical elements and molecules swallow some of the starlight, leaving distinctive gaps in the light JWST gathers up.\u00a0<\/span><\/p>\n

There are some elements and molecules that swallow infrared light, so the gaps that result can\u2019t be seen by telescopes that only pick up visible light.<\/p>\n

Water and methane \u2013 which is produced by microbes on Earth \u2013 are two key examples.<\/p>\n

Astronomers want to know how common they are among exoplanets and how abundant they are on individual exoplanets.<\/p>\n

After all, the majority of Earth\u2019s surface is covered in water.<\/p>\n

\"""\"<\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/picture><\/div>
Transmission spectrum of exoplanet WASP-96 b, captured by the James Webb Space Telescope. Credits: NASA, ESA, CSA, STScI<\/span><\/figcaption><\/div>\n

The first data release from JWST contained the transit of an exoplanet called WASP-96b, showing clear signs of water blocking the light from the star.<\/p>\n

Though this specific planet was known to have water already, JWST peered into the atmosphere of this alien world in more detail than ever before.\u00a0<\/span><\/p>\n

Despite not having been designed to examine exoplanets, it\u2019s extremely suited to the task.<\/span><\/p>\n

Previous exoplanetary telescopes had big gaps in their data, as their orbits dip in and out of Earth\u2019s shadow.<\/span><\/p>\n

JWST, 1.5 million kilometres from home, has no such problem.\u00a0<\/span><\/span><\/p>\n

The sheer size of its primary mirror means it can measure the atmospheres of smaller planets than previously possible, including potentially habitable worlds in the TRAPPIST-1 planetary system<\/a>.\u00a0<\/span><\/p>\n

Here, as in all of JWST\u2019s science aims \u2013 to see the first stars, how worlds are formed, how galaxies evolve \u2013 the most exciting observations are yet to come.<\/span><\/p>\n