The Ten Billion Dollar Telescope
Astronomers have spent a fortune on the James Webb Space Telescope. Will it be worth it?
When the idea first landed on a NASA administrator’s desk, the project was supposed to be fast and cheap. For $500 million, NASA thought, they could build a telescope to reveal the secrets of the early universe. It should have taken just eleven years to build and launch; it ended up taking twenty-five.
The James Webb Space Telescope — which now has a price tag of over $10 billion— is finally, after years of delay, ready for launch. Sometime this summer the telescope will be packed up and sent by ship to Kourou in South America. In October, if there are no more delays, an Ariane rocket will loft the telescope high into orbit.
Then, in November, the telescope will reach its final destination, a million miles from Earth. By early next year we should get the first pictures back, offering the world an unprecedented glimpse of the infra-red universe.
From the beginning, the telescope has been mooted as a replacement for the aging Hubble Space Telescope. The comparison is nice, but far from the truth. Hubble is an extremely versatile telescope, giving astronomers a wide array of instruments to survey the universe. James Webb, by contrast, is specialised, focusing on infra-red light.
This wavelength, sitting invisibly on the red edge of the rainbow, is more commonly thought of as heat. Telescopes to detect it act as a kind of thermometer, seeking faint heat sources in the distant universe. But such telescopes are difficult to build and operate on Earth. Infra-red light is easily absorbed by the Earth’s atmosphere, which makes building a telescope on the ground pointless.
Instead, they are often sent high into the atmosphere on special aircraft, or, like the James Webb, placed deep into space, away from the Earth’s heat. Out there the telescope must be kept icy cold, 220°C below freezing (-370°F), to prevent the heat of the instruments themselves from messing up the observations.
These challenges go some way to explaining the high cost of the mission. While NASA anticipated developing new technologies at the start of the project, they badly underestimated the cost. The engineering challenges were extraordinary — including a huge umbrella to block out the Sun’s heat and a vast gold-plated mirror controlled by a hundred individual motors.
What makes an infra-red telescope so valuable to astronomers? The answer lies in its ability to peer across enormous distances almost to the edge of the observable universe. Hubble, which operates in the optical wavelengths our eyes use, cannot see these distant places, which also means it cannot look back to the moment the first stars and galaxies flickered into life.
When we peer deep into space, we are, thanks to the speed of light, looking back in time. Space is expanding and stretching, changing the wavelength of light travelling from the early universe. Over billions of years, light once emitted in the optical range has shifted to the infra-red — the range invisible to Hubble.
The James Webb telescope will offer as an unrivalled view of this time, allowing astronomers to spot the very first stars. They will be able to watch as primeval fluctuations left over from the Big Bang coalesce into galaxies, forming the structure of the modern Universe. In doing so the telescope will lift the veil on a so far unknown era.
Closer to home the telescope can also reveal objects that are we struggle to see at the moment. Objects like brown dwarfs — small stars that barely emit any light — or exoplanets, normally drowned out by the light of their stars. Indeed, the telescope is so powerful it may be able to directly photograph those alien planets, even revealing details about their weather.
Not all astronomers have been happy about the cost of the telescope. Its expanding budget sucked money away from other projects. As a result, the James Webb now dominates the field for astronomers — and is something they desperately hope works.
That is not at all certain. The telescope is incredibly complex and far from Earth. After Hubble launched, in 1990, astronomers were shocked to find a problem with the mirror prevented good observations. Fortunately the platform was designed for astronauts to visit, and they were able to replace the mirror.
Such a repair will not be possible for the James Webb. The telescope is too distant for astronauts to visit, and even if they could, it has not been designed for manual repair. This is a one-shot mission — either it works first time, or it will not deliver at all.
A second high energy physics experiment has revealed problems with the standard model. The experiment, located at Fermilab in Chicago, probed the magnetic moment of muons — a subatomic particle similar, but heavier than, an electron.
The result confirmed earlier suspicions that the moment is different from the value predicted by the standard model. If true this means something unexpected is happening, something that may force physicists to come up with a new theory of physics.
The result is not yet certain. Scientists need to collect and analyse more data to be sure of what they have found. Even then the experiment will be scrutinised for error, and calculations double checked for a mistake. But if it is confirmed to really exist, it is good news for a field of physics that had looked in danger of stagnation.
A few weeks ago I wrote an article on the place of astronomy in the modern world. In it I claimed that astronomers have little role in advising modern governments — a claim I now know to be wrong. In Bhutan, a tiny Himalayan kingdom, astronomers were called upon to advise the government on the correct way to roll out the COVID-19 vaccination to the population.
After analysing the stars, the astronomers (or perhaps astrologers) advised to wait two months, until the situation was more favourable. But rule by astronomer does not seem to have gone too badly for the small country. Only one person has died from the virus, and after completing the required two months, almost the entire population received their first shot within a week.
So much reporting around health, science and space exploration is unrealistic, hyperbolic and misleading. These are complicated topics, and there are often no easy or straight forward answers. Instead what is needed is analysis, discussion and an exploration of the possible ways forward.
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Re: "The James Webb Space Telescope — which now has a price tag of over $10 billion— is finally, after years of delay, ready for launch."
People who don't have overruns don't build giant space telescopes.