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Tuesday, March 28, 2023
Dr. Brown: James Webb telescope an Advent tale of creation and hope

If all goes well, the most powerful, capable, expensive and complex star-gazing satellite telescope yet – the James Webb telescope – is slated for launch aboard an Ariane 5 rocket later this month.

It’s been a quarter-century in the making and like most such projects, was over budget several times and threatened with cancellation more than once by U.S. congressional committees.

Heir to the amazing 26-year-old Hubble telescope, the James Webb telescope is bigger and much better equipped to explore the early universe, and much closer to hand, expand the search for potential life-friendly planets within our galaxy and beyond.

The budding early universe was a dense, highly ionized, plasmic soup of hydrogen and helium nuclei and free electrons – and much too hot for stable atoms to form – with the result that photons of light were trapped, unable to escape.

Then, 325,000 years following the Big Bang, the universe had cooled enough for stable atoms to form and allow those photons of light to escape. Some of that first light in the universe was within the bandwidth of visible light.

However, it wasn’t long before continued expansion of the universe stretched the signal’s bandwidth into the infrared and later radio range, through the Doppler effect, and darkness once more fell on the universe. The detection of the latter weak signal in the radio range, called the Cosmic Background Radiation, won a Nobel prize for Arno Penzias and Robert Wilson.

Then one to two million years later, hydrogen and some helium were gravitationally shaped by dark matter, and possibly giant black holes, into what would become the first stars.

The latter were giants – hundreds if not thousands of times the mass of our sun – each creating more than enough gravitational force and high enough temperatures to fuse hydrogen nuclei into helium nuclei in the star’s core and release enormous amounts of energy, much in the form of photons, which reaching the star’s surface, lit up the universe with light.

Or at least that’s what most astrophysicists think may have happened. Now with the launch of the Webb telescope, scientists hope to fill in gaps in our understanding about the evolution of the early universe by employing ultrasensitive sensors to detect infrared and radio signals that were invisible to Hubble.

Because those cosmic signals left over from the early universe are so weak, scientists and engineers took extraordinary steps to shield the primary mirror from unwanted sources of infrared and other radiation. For that reason, the telescope will be sent to a spot roughly one million miles from Earth to where the gravitational forces of the sun, Earth and moon cancel one another out, leaving the telescope fixed in space and facing away from all three radiant sources.

From conception to creation, this telescope is an amazing testament to human ingenuity, science and engineering but unlike its famous predecessor Hubble, will be on its own, beyond reach of any repair as Hubble famously needed, because of the great distance involved.

Hopefully, the Webb telescope will shed light on that most enigmatic of matter – dark matter, said to account for 85 per cent of all the matter in the universe – and dark energy, held to be responsible for the expansion of the universe.

For now, the big question is whether the Webb telescope will make it to its appointed station in space with all its parts deployed and working. As Jonathan Lunine put it in a recent review in Nature, the whole sequence from launch, “to unpacking solar arrays, antennas, booms, radiators, mirrors and the sunshield itself” is a “heart-stoppingly complex sequence.”

Let’s hope it works, because there’s no fix in reach, now or in the future.

Several years ago, I listened to a BBC series on creation stories from ancient times to the most recent – the scientific story. All speak to beginnings, interims, endings and sometimes recreations. That’s what has happened with the universe: stars have beginnings, lives and endings, and those endings are not the “end.” Our sun, for example, is the third edition in our neighbourhood.

The theme of creation, life, death and recreation is found in several of the world’s major religions and reason enough to see religious and science accounts as marvellous attempts to explain and seek meaning in the universe and life around us. It's Advent season, a time of expectation and hope, both shared by religion and science.

Next, we turn to the question of life elsewhere in the universe.

Dr. William Brown is a professor of neurology at McMaster University and co-founder of the InfoHealth series at the Niagara-on-the-Lake Public Library.  

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