Lawrence M. Krauss is a theoretical physicist, author, president of the Origins Project Foundation, and host of The Origins Podcast. His newest book, to be released next year, is The Known Unknowns: The Unsolved Mysteries of the Cosmos.
To see a World in a Grain of Sand
And a Heaven in a Wild Flower
Hold Infinity in the palm of your hand
And Eternity in an hour
So penned William Blake more than 200 years ago in his Auguries of Innocence. He would have been surprised. This week, humanity peered into the sky to see a region smaller than a grain of sand held at arm’s length to view not just one world, but billions within a seemingly infinite and perhaps eternal universe.
It was a strange scene, watching the President of the United States unveil the first James Webb Space Telescope (JWST) image released by NASA, an announcement that was decades in the making. Joe Biden’s naive enthusiasm was followed by remarks from the NASA administrator, former senator Bill Nelson, who was so excited he seemed to forget how to describe the image: a cluster of galaxies 4.6 billion light years away, gravitationally distorting and magnifying the images of many more distant galaxies.
It was a somewhat awkward beginning, but no matter. Almost immediately, the images appeared around the world.
There is a reason why this image and the thousands of others produced by JWST’s predecessor, the Hubble Space Telescope, have generated so much excitement among the public. The night sky is beautiful and mysterious. No one alive has ever walked out on a dark evening, looked up, and not pondered what wonders, or terrors, the darkness was hiding. The objects being explored by these telescopes may be distant or esoteric, but each image represents a new window on an otherwise hidden universe – the very first time any human has been able to pierce the veiled darkness of the cosmos.
The iconic opening line from Star Trek said that the mission of the USS Enterprise was “to boldly go where no one had gone before.” In the show’s fictional universe, intrepid voyagers could flit about the galaxies in a spacecraft. In the real universe that is not possible, but we can instead travel where no one has gone before with our minds thanks to the technologies humans have developed to explore the unknown, from the smallest elementary particles to the farthest reaches of the universe.
The particular image chosen by NASA as the first to be unveiled was not artistically striking, as many of the previous Hubble images have been. I expect it was chosen because it displays the most distant objects ever viewed by humans. The light from these objects has travelled more than 13 billion years to reach the telescope, being emitted less than a billion years after the Big Bang. With the exception of six intervening stars, easily discernible because of the octagonal rays surrounding them, each of the other thousands of dots in the image is another galaxy, containing billions of its own stars.
The most distant galaxies in this false colour image (JWST was designed to detect infrared, not visible light, because the most distant objects in the universe are moving away from us so fast that the light they emit gets stretched from visible to infrared wavelengths) appear as yellowish circular arcs, centred on an intervening cluster of brighter, whitish galaxies. They are only visible because the gravity due to the cluster bends space around it, magnifying distant objects, just as a telescope lens does. This “gravitational lensing” effect has been observed before, but never with such clarity and depth.
One of the central missions of JWST is to search back for what has been called “first light,” when the earliest stars and galaxies in the universe began to shine, perhaps 100 million years after the Big Bang. In so doing we will learn more about how galaxies, including our own, came to be, and whether supermassive black holes observed in the centre of many formed before or after their hosts. Resolving those mysteries will, in turn, help answer the fundamental question of how our own existence became possible. Perhaps we will even learn the nature of the mysterious dark matter that seems to dominate the mass of almost all known galaxies.
The four images released Tuesday were undoubtedly chosen to illustrate the other strengths of JWST. The Carina Nebula and the Southern Ring Nebula display the visual effects of the birth and death of stars, some many times more massive than our sun. While they are of intrinsic interest to scientists, their striking beauty gives a small taste of the remarkable sights yet to be unveiled. Stephan’s Quintet is a small compact group of galaxies 290 million light years away that was first observed in 1877. With the resolution of JWST, four of these five galaxies are captured in the midst of a cosmic pirouette as they move, tied together by their gravitational attraction. As they are tugged and pulled, their shapes are distorted, and one can also see evidence of bursts of young stars forming inside of them.
Finally, NASA released the spectrum of light observed from a giant Jupiter-sized planet, WASP-96, located more than 1,000 light years away and orbiting its star every 3.4 days, with clear evidence of water vapour in its atmosphere. It represents one of the most exciting missions of JWST: to observe light from distant planets and in so doing explore their atmospheres. The atmosphere of Earth has forever been changed by the presence of life. No free oxygen, for example, existed in the early Earth. Only through the respiration of tiny single-celled life forms over billions of years did the present oxygen abundance develop. While observing oxygen alone in the atmosphere of a distant exoplanet will not prove the existence of life there, if we can search for other biosignatures, we may finally answer the question of whether life on Earth is unique in the universe.
Addressing fundamental questions that humanity has grappled with throughout its history – from “How did we get here?” to “Are we alone in the universe?” – will undoubtedly be one of the legacies of JWST, as well as a continuing source of the fascination for both scientists and the public. But I think the most significant legacy is likely to be not what JWST will reveal regarding present scientific debates, but how JWST will affect the future direction of science.
In his own bumbling way, NASA’s Mr. Nelson captured this issue when he said, “We are going to be able to answer questions that we don’t even know what the questions are yet.”
That is, after all, the beauty and power of science. The most exciting discoveries are the ones that are not anticipated. There is much we know we don’t know about the universe. But more amazing are the “unknown unknowns.”
To paraphrase a poet more ancient than Blake, there are more things in heaven and Earth than we currently even dream about. The imagination of nature far exceeds the human imagination, which is why we need to keep reaching out and exploring, with our telescopes, our particle accelerators, and the other more modest scientific tools that drive discovery.
In that regard, maybe not just presidents, but the rest of us, can use a break from the often-bleak news of the present. While unveiling our past, exploration like that epitomized by JWST can also give us hope of an even more exciting future.
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