The James Webb Space Telescope is among MIT Technology Review's 10 Breakthrough Technology of 2023. You can find the rest of this list here.
Natalie Batalha was eager to get data from the James Webb Space Telescope. After the telescope had completed its final orbit, it was still a few months before the University of California Santa Cruz had given Batalha the opportunity to observe a few exoplanets, which orbit around other stars.
WASP-39b was one of the targets. It is a hot world that orbits a star 700 light-years away from Earth. It was discovered many years ago. Batalha and her colleagues discovered the planet in July. They were able to observe the distant world's first JWST observations. In mid-July they noticed a signature that was common on Earth, but not in the atmosphere of an extraplanet. It was carbon dioxide. Carbon dioxide is an indicator of plant and animal existence on Earth. WASP-39b takes only four Earth days to orbit its star and is therefore not considered habitable. However, the discovery could lead to more interesting discoveries from more temperate planets in the future. It was just days into JWST's lifetime. Batalha says, "That was an exciting moment," as he explains that his group had seen the data for the very first time. "The carbon dioxide feature was clearly drawn out from the first time we looked."
This was not an accident. JWST is a NASA-led NASA collaboration between the US and Canada. It can view objects 100x fainter than the Hubble Space Telescope. Amazing views from all over the universe began to flood down almost immediately after the telescope was fully operational in July 2022. These included images of distant galaxies at dawn of time and stunning landscapes of nebulae (the dust-filled birthplaces for stars). Gabriel Brammer, an Astronomer at the University of Copenhagen, Denmark, says, "It's just like we had hoped. If not more so."
JWST's ability to make discoveries at a rapid pace is not due to its inherent capabilities. Astronomers worked for years to prepare for the observations it would make. They developed algorithms that quickly turn their data into useful information. The vast majority of the data is available for free, so the community can comb through it as fast as possible. The telescope's predecessor, Hubble has been used as a model by its operators to pack as many observations as possible.
Some people were surprised by the volume of data. Heidi Hammel is a NASA interdisciplinary scientist for JWST, and vice president for science at The Association of Universities for Research in Astronomy in Washington DC. "It was more that we expected," she says. It was non-stop once we got into operational mode. We were constantly looking at a star formation, an exoplanet, or galaxy every hour. It was like a firehose.
Months later, JWST is still sending down massive amounts of data to astonished Earth astronomers. It is expected to revolutionize our understanding of the distant universe and exoplanets, as well as galactic structure and planet formation. Although not all have been able to enjoy the rush of activity, it has sometimes reflected an emphasis upon speed over scientific process. However, there is no doubt that JWST is captivating audiences around the world at a phenomenal pace. The floodgates are open and they won't close anytime soon.
Open the pipe
JWST orbits around the sun at 1.5 million kilometers from Earth. The primary mirror is as large as a giraffe and is coated in gold. It is shielded from the sun's glare with a sunshield tennis-court-sized. This allows for unprecedented views of the universe through infrared light.
It was a long process to get the telescope. It was first designed in the 1980s and originally planned to launch in 2007 at $1 billion. Its complexity led to delays and costing much more money than originally planned. JWST launched in December 2021 at a cost of $1 billion.
There were anxious moments even after launch. It took the telescope a month to reach its destination beyond the moon's orbit. Hundreds of moving parts were needed to deploy its many components.
Our goal is to keep the telescope busy: "The worst thing that we could do, is have an inactive telescope."
The budget overruns and delays have all been resolved. JWST is hard at the job, with its activities meticulously planned by the Space Telescope Science Institute in Baltimore. Each week, a team plans the telescope's future observations. They use a long-term list of hundreds of programs that have been approved to be used in the telescope's first year of science (July 2022 through June 2023).
It is important to keep the telescope busy. Dave Adler, STScI's head of long-range planning at JWST, says that "the worst thing we can do is have an inactive telescope." It's expensive. In the 1990s Hubble could sometimes find itself in space, twiddling its thumbs if programs were changed or canceled. JWST's schedule has been deliberately oversubscribed to avoid such problems. The telescope is moved with precision by the onboard reaction wheels and thrusters, which rotate to alter the orientation. Adler says, "The goal is to minimize the time we aren't doing science."
This packed schedule means that JWST can gather more than 50 gigabytes every day, as opposed to just one or two gigabytes from Hubble. STScI runs an algorithm that feeds the data. This algorithm includes images and spectroscopic signatures, which are light fragmented into their elements. It is also known as a "pipeline" and transforms the telescope's raw numbers and images into useful information. Some of the data is immediately released on public servers where it can be accessed by scientists and Twitter bots like the JWST Photo Bot. Scientists are also given data via programs with proprietary windows. This allows them to spend time analysing their data before it is released.
Pipelines are basically pieces of code made using programming languages such as Python. Pipelines have been around for a long time, but they were greatly improved in 2004 when Hubble was used by astronomers to spend 1,000,000 seconds looking at an empty area of sky. It was intended to search for distant galaxies within the distant universe. However, 800 exposures were required so Hubble's planners knew that it would prove too difficult to accomplish manually.
Instead, they created a pipeline to convert the exposures into usable images. This was a difficult technical challenge because each image required its own calibration. Anton Koekemoer is a STScI research astronomer. He says, "It was impossible to expect the community at that point to combine 800 exposures themselves." "The goal was for science to be performed faster." An incredible image that resulted from those efforts showed 10,000 galaxies spread across the universe in what became known as the Hubble Ultra Deep Field.
JWST is a single, STScI-developed master pipeline that takes images and data from all of its instruments and makes them science ready. To further analyze the data, amateur and professional astronomers use the pipelines they have built in the months or years prior to launch. Astronomers were able almost instantly to understand the JWST data stream, which turned what would normally take months of analysis into hours of processing.
Brammer says, "We were sitting there ready." "All of a suddenly, the pipe opened. We were ready to go."
Galaxies all around
The Hubble Space Telescope orbits just a few hundred kilometers above Earth's surface. It is easily accessible for astronauts. They did so over the years. A series of missions were undertaken to repair and upgrade this telescope. The first was to repair its famously distorted mirror, which was discovered in 1990 shortly after launch. JWST is a satellite that sits further away from the moon than it is from Earth.
Lee Feinberg, JWST’s optical telescope element manager at NASA’s Goddard Space Flight Center was one of those who waited to see if the telescope would deliver. He says that the team spent 20 years preparing the telescope's alignment, which is to ensure it pointed at targets in the sky.
The wait was over by March. JWST had finally reached its destination beyond the moon and Feinberg and his coworkers were ready to begin taking test images. One of the images, a test picture of a star, was displayed to Feinberg as he entered STScI. It was a surprise. Feinberg says that there were hundreds of galaxies. "We were just stunned." The image was so detailed that it showed galaxies stretching out into the faraway universe. It wasn't intended for this purpose. He says, "Everybody was stunned at how well it worked."
After a process of calibrating and testing instruments, JWST was able to view WASP-39b using its cryogenically-cooled Mid-Infrared instrument (MIRI). This instrument is the one that telescopes use to observe the most infrared portion of the spectrum. Here many signatures of planet atmospheres can easily be detected. The MIRI spectrograph enabled scientists to distinguish the light coming from WASP39b's atmosphere. Instead of manually analysing the observations, however, the team used Eureka!, a pipeline developed by Taylor Bell at NASA's Ames Research Center, California. Bell says, "The objective was go from the raw data to information about the atmosphere spectrum." This type of analysis would normally take months. The signature of carbon dioxide was discovered within hours. The planet has also been given a host of additional details, including an analysis of its composition and the presence patchy clouds.
Others have used pipelines to reach distant targets. Rohan Naidu, MIT's chief scientist, discovered GLASSZ13 in July. This remote galaxy's light could have been found 300 million years earlier than any other galaxy. This discovery caused an uproar worldwide because it suggested galaxies could have formed earlier than expected, possibly by several hundred million years. It also meant that our universe developed faster than we thought.
EAZY, which Brammer created to crudely analyze JWST images for light of galaxies, was instrumental in Naidu's discovery. Brammer posted the tool on the software site GitHub, where anyone can use it.
Rush hour
Scientists submit scientific papers to journals. The paper is then reviewed by other scientists in the field, and finally accepted or rejected for publication. Sometimes, this process takes months or even years and can delay publication. However, it is always done with scientific rigor and accuracy.
However, there are many ways to avoid this process. One popular way to bypass peer review is to post early versions on arXiv. This allows research to be read and publicized before it is published in journals. Sometimes, research is not submitted to a journal and instead remains on arXiv. Scientists can discuss the research on Twitter or other forums.
When scientists discover a new discovery, they are eager to publish it on arXiv. Sometimes this happens before other papers. JWST's first-year programs, which comprise about a fifth, are open access. This means that data can be immediately made available to the public once it has been transferred down to Earth. This puts the team that developed the program in direct competition with other researchers who are watching the data flow in. Many researchers used arXiv to publish their early results, whether they were good or bad, when the telescope's data stream began to flow in July.
"When dealing with something so new and unknown, it is important to check things 10 or 100 times. This is not the way things worked ."
Emiliano Merlin
Emiliano Merlin, an Astronomical Observatory of Rome, says that there was a rush for anything to be published as soon as possible. He was also involved in JWST analysis efforts like the race to locate galaxies in distant universes after the Big Bang. GLASS-z13 was discovered before any follow-up observations could confirm their age. Merlin says, "It wasn't something I liked personally." Things should be checked ten to 100 times when dealing with something so new and unknown. This is not the way things were.
One concern was that errors could have been caused by early calibration problems with the telescope. However, most of the early results have held up to scrutiny. GLASS-13 was confirmed to be an early record-breaking galaxy by follow-up observations. However, its age has been reduced slightly, which led to the renaming of this galaxy to GLASS-1212. It is possible that other galaxies formed earlier than GLASS-12, which suggests that we may need to rethink our understanding of how the universe developed.
Many JWST programs release data immediately. This can sometimes lead to a rush to post results. However, around 80% of the programs have a proprietary period that allows researchers to access their data for 12 month. This allows scientists, particularly smaller groups, to scrutinize their data more closely before making it available to the public.
Mark McCaughrean (senior advisor for science and exploration, European Space Agency) says that private time helps to balance out any bumps in resources. He is also a JWST scientist. You can stack it in the direction for the big teams if you remove proprietary periods."
However, many scientists don't use their entire 12-month allowance. This will mean that they will only increase the continuous stream of discoveries from JWST. In addition to open-access observations, more proprietary results will be made available to the public. Hammel says, "Now that we have the firehose open, we will continue to see papers for the next 10 and beyond." It may be well beyond that. Einberg claims the telescope could have more fuel than 20 years, which would allow operations to continue into the 2040s.
Hammel says, "We're opening up an entirely new window onto the universe." Hammel says, "That's just an exciting moment to be part of, as a species."
This story was also published in the January/February 2023 issue.
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By: Jonathan O’Callaghan
Title: How the James Webb Space Telescope broke the universe
Sourced From: www.technologyreview.com/2023/01/21/1065178/james-webb-space-telescope-universe/
Published Date: Sat, 21 Jan 2023 12:00:00 +0000
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