Martin Barstow, Professor of Astrophysics and Space Science, University of Leicester
If everything goes according to plan, we will soon enter a new era of astronomy. The James Webb Space Telescope (JWST), the largest and most expensive and complex space telescope ever built, is now in space, heading to its final destination.
The launch of the $10 billion James Webb Space Telescope on Christmas Day 2021, anticipated for over a decade, was both exciting and terrifying for the thousands of scientists, engineers, managers and support staff who brought the mission to this point. As chair of the Space Telescope Science Institute Council, which will run the operations centre for JWST, I shared their nervousness. JWST’s scientific potential is after all enormous and it could answer some of the biggest questions about the universe.
JWST is often billed as a replacement for the Hubble Space Telescope, but I would prefer to view it as a successor. Hubble has now operated for more than 30 years and given us amazing views of the universe and many thousands of scientific results. We hope and anticipate that it will continue to operate for many more years.
But the relatively small 2.4-metre diameter mirror, compared to ground-based telescopes, limits its sensitivity and ability to observe the faintest objects. Also, although Hubble has some capability to observe in infrared light, it cannot access the wavelengths of light from the very earliest stars and galaxies. JWST, however, will be able to do so. It may even be able to see Population III stars (stars that formed from primordial material from the Big Bang) which have never been glimpsed before.
Knowing when the first stars were formed, soon after the Big Bang, and understanding how they produced the building blocks of the first galaxies is an important scientific question and one of the primary science goals of JWST. We know that the elements that are needed for life and modern technology, such as carbon, silicone and gold, were ultimately created in early stars — but we don’t currently have a good understanding of how this happened.
The need to detect faint objects in the distant universe has been an important driver for the design of the observatory, determining its size, wavelength coverage and need to keep it very cool to minimise undesirable background light.
Studying the first stars and galaxies is not the only scientific programme JWST will perform. It is conceived as a general-purpose observatory on which astronomers from around the world can apply for time to support their research. For example, observing in the infrared will allow JWST to see through the clouds of dust that enshroud very young stars, which are opaque to visible light.
Unlike Hubble, it will be able to see right into stellar nurseries, where stars and their planetary systems are being born. The observations will answer questions about how the clouds of dust and gas collapse to form stars and how planetary systems form around them.
Stars form inside dusty nebulas, such as the one in the constellation Orion. (Image credit: NASA,ESA, M. Robberto (Space Telescope Science Institute/ESA) and the Hubble Space Telescope Orion Treasury Project Team)
Exoplanet habitability
When the first plans for JWST were being discussed more than 20 years ago, no planets were known other than those in our own solar system. Since then, astronomers have discovered thousands of planets orbiting other stars in our galaxy (exoplanets). A significant fraction of the JWST observing programme will be devoted to the study of their atmospheres. The wavelength coverage of JWST is particularly well tuned to studying molecules in exoplanet atmospheres and the low infrared background from space, giving it a considerable advantage over Earth-based telescopes.
Two techniques are available. One takes advantage of the fact that planets can pass in front of their parent star (called a transit), creating a dip in the light we see from it. By analysing the light, broken down by wavelength, with great precision before and during a transit we can probe the planet’s atmosphere to unveil what molecules it consists of. Another technique uses a special instrument called a coronagraph to block the light from the parent star to enable direct imaging of the planet and study its atmosphere or surface. This could help unveil whether a planet is suitable for life, perhaps warranting further investigation and one day sending mini space probes there.
The ultimate goal is to find a planet similar to the Earth, but it would require a very lucky combination of circumstances, because they are likely to be rare in the solar neighbourhood and very faint compared to the parent star. Most likely, JWST will study gas giants like Jupiter and Saturn or ice giants similar to Uranus and Neptune in our own solar system. None of the known planetary systems resemble our own, with many giant planets in closer orbits than ours, and more extreme heating of their atmospheres and more dynamic weather conditions.
In addition to studying planets outside our solar system, JWST will be able to observe our home planetary system. Its great sensitivity will enable the identification and characterisation of comets and other icy bodies in the outermost regions of the solar system. In such a remote location, these objects are largely unchanged since their formation, and may contain clues to the origins of Earth, particularly the source of its water, which may be the result of bombardment by such bodies early in its lifetime.
JWST will also be able to observe all the planets that lie outside Earth’s orbit of the sun, studying their atmospheres and seasonal weather variations.
Detailed plans and ideas for what will be discovered are essential justification for the expense of building an ambitious, game-changing telescope such as JWST. But there will be discoveries that nobody can anticipate. When Hubble was launched, the idea of exoplanets was largely science fiction, yet studying exoplanets became one of its major tasks. I wonder what surprising science awaits us with JWST.
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NAIROBI, Kenya (AP) — The body of Ugandan Olympic athlete Rebecca Cheptegei — who died after being set on fire by her partner in Kenya — was received Friday by family and anti-femicide crusaders, ahead of her burial a day later.
Cheptegei’s family met with dozens of activists Friday who had marched to the Moi Teaching and Referral Hospital’s morgue in the western city of Eldoret while chanting anti-femicide slogans.
She is the fourth female athlete to have been killed by her partner in Kenya in yet another case of gender-based violence in recent years.
Viola Cheptoo, the founder of Tirop Angels – an organization that was formed in honor of athlete Agnes Tirop, who was stabbed to death in 2021, said stakeholders need to ensure this is the last death of an athlete due to gender-based violence.
“We are here to say that enough is enough, we are tired of burying our sisters due to GBV,” she said.
It was a somber mood at the morgue as athletes and family members viewed Cheptegei’s body which sustained 80% of burns after she was doused with gasoline by her partner Dickson Ndiema. Ndiema sustained 30% burns on his body and later succumbed.
Ndiema and Cheptegei were said to have quarreled over a piece of land that the athlete bought in Kenya, according to a report filed by the local chief.
Cheptegei competed in the women’s marathon at the Paris Olympics less than a month before the attack. She finished in 44th place.
Cheptegei’s father, Joseph, said that the body will make a brief stop at their home in the Endebess area before proceeding to Bukwo in eastern Uganda for a night vigil and burial on Saturday.
“We are in the final part of giving my daughter the last respect,” a visibly distraught Joseph said.
He told reporters last week that Ndiema was stalking and threatening Cheptegei and the family had informed police.
Four in 10 women or an estimated 41% of dating or married Kenyan women have experienced physical or sexual violence perpetrated by their current or most recent partner, according to the Kenya Demographic and Health Survey 2022.
TEL AVIV, Israel (AP) — A rare Bronze-Era jar accidentally smashed by a 4-year-old visiting a museum was back on display Wednesday after restoration experts were able to carefully piece the artifact back together.
Last month, a family from northern Israel was visiting the museum when their youngest son tipped over the jar, which smashed into pieces.
Alex Geller, the boy’s father, said his son — the youngest of three — is exceptionally curious, and that the moment he heard the crash, “please let that not be my child” was the first thought that raced through his head.
The jar has been on display at the Hecht Museum in Haifa for 35 years. It was one of the only containers of its size and from that period still complete when it was discovered.
The Bronze Age jar is one of many artifacts exhibited out in the open, part of the Hecht Museum’s vision of letting visitors explore history without glass barriers, said Inbal Rivlin, the director of the museum, which is associated with Haifa University in northern Israel.
It was likely used to hold wine or oil, and dates back to between 2200 and 1500 B.C.
Rivlin and the museum decided to turn the moment, which captured international attention, into a teaching moment, inviting the Geller family back for a special visit and hands-on activity to illustrate the restoration process.
Rivlin added that the incident provided a welcome distraction from the ongoing war in Gaza. “Well, he’s just a kid. So I think that somehow it touches the heart of the people in Israel and around the world,“ said Rivlin.
Roee Shafir, a restoration expert at the museum, said the repairs would be fairly simple, as the pieces were from a single, complete jar. Archaeologists often face the more daunting task of sifting through piles of shards from multiple objects and trying to piece them together.
Experts used 3D technology, hi-resolution videos, and special glue to painstakingly reconstruct the large jar.
Less than two weeks after it broke, the jar went back on display at the museum. The gluing process left small hairline cracks, and a few pieces are missing, but the jar’s impressive size remains.
The only noticeable difference in the exhibit was a new sign reading “please don’t touch.”
VICTORIA – The British Columbia government is partnering with a bear welfare group to reduce the number of bears being euthanized in the province.
Nicholas Scapillati, executive director of Grizzly Bear Foundation, said Monday that it comes after months-long discussions with the province on how to protect bears, with the goal to give the animals a “better and second chance at life in the wild.”
Scapillati said what’s exciting about the project is that the government is open to working with outside experts and the public.
“So, they’ll be working through Indigenous knowledge and scientific understanding, bringing in the latest techniques and training expertise from leading experts,” he said in an interview.
B.C. government data show conservation officers destroyed 603 black bears and 23 grizzly bears in 2023, while 154 black bears were killed by officers in the first six months of this year.
Scapillati said the group will publish a report with recommendations by next spring, while an independent oversight committee will be set up to review all bear encounters with conservation officers to provide advice to the government.
Environment Minister George Heyman said in a statement that they are looking for new ways to ensure conservation officers “have the trust of the communities they serve,” and the panel will make recommendations to enhance officer training and improve policies.
Lesley Fox, with the wildlife protection group The Fur-Bearers, said they’ve been calling for such a committee for decades.
“This move demonstrates the government is listening,” said Fox. “I suspect, because of the impending election, their listening skills are potentially a little sharper than they normally are.”
Fox said the partnership came from “a place of long frustration” as provincial conservation officers kill more than 500 black bears every year on average, and the public is “no longer tolerating this kind of approach.”
“I think that the conservation officer service and the B.C. government are aware they need to change, and certainly the public has been asking for it,” said Fox.
Fox said there’s a lot of optimism about the new partnership, but, as with any government, there will likely be a lot of red tape to get through.
“I think speed is going to be important, whether or not the committee has the ability to make change and make change relatively quickly without having to study an issue to death, ” said Fox.
This report by The Canadian Press was first published Sept. 9, 2024.
