Jan J. Eldridge
Associate Professor Jan J. Eldridge is an astrophysicist and head of the Physics Department at the University of Auckland.
Science
The images from NASA’s James Webb Space Telescope allow us to track the evolution of the universe and our galaxy, and to understand our own origins – and possibly find habitable planets around other stars.
Remark: The James Webb Space Telescope (JWST) should be called the Just Wow Space Telescope. The new images it has produced are images of the universe we’ve seen before, but the clarity and detail are like a masterpiece restored to its full glory.
The telescope has been decades in the making with a huge international team of thousands of scientists and engineers working to dream, imagine, design and build it. What we have seen shows that they have achieved exactly what those first dreams were looking for.
Zooming in on these images reveals many new details. There are several faint arcs made up of many small bright dots, each of which is a galaxy. The details and information are amazing. The images have texture – there is “lumpinef” in the gas clouds in which new stars are being formed.
The other real strength of the telescope is that all observations are in infrared light, with longer wavelengths than red. It’s the kind of light that warms your hands when you hold them against a hot object. The JWST can view the entire light range at these wavelengths.
This is useful for two reasons. The wavelength of light emitted by a hot object depends on its temperature. For our sun, around 6000C, this is in the middle of the optical spectrum, which is equivalent to daylight. The JWST can also look at much cooler objects that are the same temperature as us – 37C – or colder. Now we can map the temperature of different dust clouds or stellar winds to understand their dynamics.
The second reason concerns dust. These clouds of particles, about the size of cigarette smoke, scatter and obscure our usual view of distant stars. In the plane of our galaxy, dust clouds block most stars. However, dust does not scatter infrared light, so we can see many more stars in our galaxy and galaxies in the Universe that were previously shrouded in dust.
But however large the infrared images may be, the truly spectacular progress is the spectra obtained. One of the first images released is an accurate observation of water in the atmosphere of a hot Jupiter-sized exoplanet, WASP-96b – a planet orbiting another star.. Although it is not habitable, it shows that it will be much easier to study nearby exoplanets in our own galaxy.
The spectra transform our knowledge because the signature in the light of water is so clear. Previous studies have always had significant uncertainty in the observations, but with these smaller errors, no one can dispute the finding.
These smaller uncertainties also mean that we may be able to detect water on smaller planets, and perhaps other molecules. This is the path to finding habitable planets around other stars, and perhaps even indicators of life.
I find the second spectra released from one of the small dots in the deep field image. This is a spectrum of a galaxy with a redshift of 8.5. This means that we can see the cosmos as it was 13.1 billion years ago, when the universe was only 600 million years old.
The second spectra reveal multiple emission lines of oxygen, neon and hydrogen. The fact that they are so bright and so bright will change our understanding of how galaxies and the composition of elements evolve through cosmic history. We also know that the stars in these galaxies evolve differently than those in our own galaxy, so it opens up new areas to explore.
All this can be inferred from a few new images. With more results from near and far objects, the JWST will reveal so many new aspects of our universe. The images allow us to trace the history of the evolution of the universe and our galaxy and to understand our own origins, which are part of the universe’s 13.7 billion year journey.