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This article comes from the official account of Wechat: ID:fanpu2019, by Wang Shanqin

On December 14, 2022, Nature magazine named Jane Rigby, a project scientist at the James Webb Space Telescope, as the top 10 in 2022 for promoting the successful operation of Webb. The next day, Science magazine listed the successful operation of Webb as one of the top ten scientific breakthroughs in 2022. What are the important achievements of Webb, which has only been one year since its launch, that it has won such honors with the scientists who promoted it? Why is it so powerful? What does its success enlighten us? This article will attempt to answer these questions.

On December 14, 2022, Nature magazine announced the person of the year (Nature's 10), topped by the project scientist and astrophysicist Jane Rigby of the James Webb Space Telescope (James Webb Space Telescope).

Nature magazine called Jane Rigby "Sky hunter" and called her a "pioneering astronomer". She was selected because "she played a key role in getting the James Webb Space Telescope into space and working properly, providing huge new capabilities for the study of the universe." [1]

Photo: a screenshot of the Nature's 10 web page. Photo Source: [1] on December 15, 2022, Science magazine listed the top 10 scientific breakthroughs of 2022, with Webb's successful operation topping the list. [2] [Note 1] an art picture of Webb's main mirror at the top of the relevant web page.

Photo: science magazine's top screenshot of the top ten scientific breakthroughs of 2022. Photo Source: [2] the honor that Webb and the astronomers who promoted it is a testament to Webb's great success. So what are the important achievements of Webb, which has only been one year since its launch, that it has won such an honor with the scientists who promoted it? Why is it so powerful? What does its success enlighten us?

Picture: Webb's artistic imagination. Photo Source: [3] what has Webb achieved? Webb has spent a whole year in space since its launch on December 25, 2021. During the year, it took scientists on the ground about half a year for it to achieve orbital transfer, hundreds of operations and tests. After that, Webb entered the state of observation, and astronomers processed the first batch of observed data into images, which were released on July 11 and 12, 2022, respectively.

The images include long-exposure images of the sky region where galaxy cluster SMACS J0723.3-7327 is located, light curves and transmission spectra of WASP-96, the parent star of exoplanet WASP-96b, images of the Southern Ring Nebula, images of the five-galaxy Stephan's Quintet, and images of a region of the Carina Nebula (NGC 3324). We have presented these results before, and without repeating them here, interested readers can click to read "return on $10 billion Investment: how strong are the first photos of the Webb Space Telescope?" ".

The quality and clarity of the first batch of images not only meet the aesthetic taste of the public, but also meet the requirements of professional astronomers, proving Webb's excellent performance. It can be said that Webb's debut is the pinnacle. After this peak, Webb did not go downhill, but continued to climb new peaks in different areas.

We can briefly summarize the first batch of achievements and the new achievements achieved so far in different areas.

In the "deep field" field, Webb observed different regions of the sky and photographed a number of high redshift (long-range) galaxies, some of which broke the previous record for the farthest galaxies observed by Hubble. The in-depth study of these galaxies will directly deepen human understanding of the properties of galaxies in the early universe. Webb's success in this area leads people to believe that it is expected to discover the first generation of galaxies and stars in the universe, which formed about 100-200 million years after the Big Bang.

Photo: Webb's infrared deep-field pseudo-color image obtained after observing the area observed by the Hubble Super Deep Field (Hubble Space Telescope's Ultra Deep Field) project that year. The spectra of some of these galaxies were obtained by Webb's near infrared spectrometer (NIRSpec), and the redshifts of four of these galaxies are shown: 13.20,12.63,11.58 and 10.38. When the redshift is 13.20, the age of the universe is less than 400 million years. Source: [4] in the galaxy field, Webb took images of galaxies such as the Stephen Quintet, the Cartwheel galaxy, and the active galaxy NGC 7469. The observation and study of these galaxies provide an important basis for people to understand the distribution of stars, gas and dust in these galaxies.

Image: the pseudo-color image of NGC 7469 is synthesized from the data obtained by Webb's near-infrared camera. The obvious core makes the image appear obvious diffraction awns. Image source: [5] in the nebula field, Webb took images of the Southern Ring Nebula, the Carina Nebula, the Tarantula Nebula, the Orion Nebula and the Pillar of creation. These observations provide important support for astronomers to study the properties of relatively cold dust and gas disks in the late evolution and embryonic stages of small and medium mass stars ("protostars") and their surroundings.

Image: the pseudo-color diagram of the Pillar of creation synthesized by the data obtained by Webb's near-infrared camera (left) and the pseudo-color diagram of the Pillar of creation obtained by Webb's mid-infrared equipment (right). Image source: [6] in the field of celestial bodies in the solar system, Webb observed celestial systems such as Jupiter, Mars, Neptune and Titan. The images obtained by Webb confirm that its ability in this area is also better than expected, and Webb's future observations of celestial bodies in the solar system will deepen people's understanding of their properties and the origin of the solar system.

Image: a pseudo-color map of the Neptune system synthesized from data obtained by Webb's near-infrared camera. The picture shows Neptune's multi-layer rings and seven of the 14 moons: Triton, Galatea, Naiad, Thalassa, Despina, Proteus and Larissa. Because Triton is dotted and bright, the hexagonal awn caused by the diffraction effect is obvious. Image source: [7] in the field of exoplanets (extrasolar planets), Webb took the light variation curve and transmission spectrum of WASP-96, the parent star of exoplanet WASP-96b, using the transit method, and captured the image of exoplanet HIP 65426 b by direct imaging. The analysis shows that Webb's ability to detect planets by direct imaging is 10 times higher than expected. Although Webb is not the first, let alone the only telescope to capture images of exoplanets in this way, it has a unique advantage in infrared observation that many other telescopes do not have. Webb's future observations of exoplanets are expected to help people identify exoplanets similar to Earth.

Image: Webb's near-infrared camera (NIRcam) and mid-infrared equipment (MIRI) capture images of exoplanet HIP 65426 b at 3.067 microns, 4.397 microns, 11.307 microns and 15.514 microns (small image below, from left to right). The larger picture shows the stars in the sky where star HIP 65426 is captured by the Digital Sky Survey (DSS). Image source: [8] in the field of supernovae, Webb discovered four supernovae in 2022. [note 2] in the current situation of fierce competition among various large field of view telescopes, Webb, who has a small field of view, has no time to discover that those close supernovae will be preempted by other telescopes, so he can only find very distant supernovae, which are characterized by being so dark that other telescopes with relatively small caliber cannot detect them in time. Webb can find more supernovae at great distances in the future. [note 3]

Why is Webb so powerful? Webb's great success comes from the advanced functions of his main mirror and instruments, as well as the positive and negative lessons provided in the development of many telescopes in the past.

First of all, Webb's main mirror and instruments are very advanced. Its caliber (6.5 meters) is much larger than that of the previous Hubble (2.4 meters) and the Spitzer Infrared Space Telescope (0.85 meters).

Photo: the sizes of Spitzer, Hubble and Webb are shown from top to bottom. Although the diameter of Webb in the picture is marked as 6.6 meters, its equivalent diameter is 6.5 meters. Image source: [9] therefore, when looking at the same infrared band, Webb has a much higher resolution than Hubble and Spitzer. Because the aperture is much larger, Webb takes much shorter observation time to observe the same target and obtain the same quality image, so it is much more efficient.

Image: left and right are images of a region in the large Magellanic Cloud (LMC) galaxy captured by Spitzer's infrared array camera (IRAC) and Webb's mid-infrared device (MIRI). The two observation wavelengths are almost exactly the same (8.0um vs 7.7um), but Webb's image resolution is clearly much higher than Spitzer's resolution. Image source: [10] Webb is far from Earth, it has five shields and its infrared devices carry additional refrigerators, so the observable wavelength limit (28 microns) far exceeds the Hubble wavelength limit (no more than 2.5 microns). So many objects that Hubble cannot find, such as protostars hidden deep in the nebula.

Photo: in Webb's near-infrared images of parts of the Carina Nebula, astronomers have found more than 20 jets and outflows that have not previously been detected by telescopes such as Hubble. The areas circled in the picture are enlarged and placed to the right. These regions show molecular hydrogen outflow (molecular hydrogen outflows), and region 2 also shows jets (jet) and bow shock waves (bow shock). Image source: [11] secondly, before Webb, humans had launched a large number of space telescopes that covered all bands of electromagnetic waves except radio bands: gamma rays, X-rays, ultraviolet rays, optics (visible light), infrared and microwaves. [note 4] taking the infrared space telescope as an example, as early as 1983, man launched the Infrared Astronomical Satellite (The Infrared Astronomical Satellite,IRAS), which is the first infrared space telescope in human history. The technology accumulated in the development and launch of these space telescopes, especially infrared space telescopes, has provided Webb with a great deal of positive experience.

Picture: IRAS's artistic imagination. Image source: [12] take the technical reference as an example, the refrigerator mode used by the mid-infrared equipment (MIRI) on Webb, the NICMOS of "Hubble" was used in 2002-2008. Webb's mirror was plated with gold to enhance reflectivity, which was previously used by the Infrared Space Telescope (The Infrared Telescope in Space,IRTS) and Akari satellites. Webb used beryllium to cast mirror billets to improve hardness, temperature adaptability and reduce weight, a scheme previously adopted by the Spitzer telescope.

Photo: Dave Chaney, chief optical test engineer at Bohr Aerospace (Ball Aerospace), examines six pieces of Webb's main mirror before performing X-ray and cryogenic tests. Image source: [13] in addition to the above-mentioned scheme from space telescopes, Webb also draws lessons from the multi-mirror splicing technology of large ground-based telescopes. This technology is commonly used in 10-meter optical telescopes on the ground, and it is also used in some 6-8-meter telescopes. It is also one of the mainstream schemes for future 30-40 m ground optical telescopes. So we can say that Webb is a giant standing on the shoulders of giants.

Picture: the main mirror of Webb is made up of 18 regular hexagonal mirrors. The side length of each mirror is about 0.75 meters and the area is about 1.4 square meters. The total area of the 18 mirrors is 25.4 square meters, which is spliced into a mirror with an equivalent diameter of about 6.5 meters. Photo Source: [14] the third factor in Webb's strength is that he has fully absorbed some of the lessons of the past, especially the painful lessons of Hubble. At that time, there was a slight deviation when the engineer was grinding the main mirror of "Hubble", which led to the inability of the mirror of "Hubble" to focus accurately, thus affecting all instruments, which not only cost NASA hundreds of millions of dollars later to repair "Hubble", sacrificed an instrument space for a long time (used to install the optical corrector COSTAR), but also had a great negative impact on Hubble's performance in the three years from 1990 to 1993. It was not until the end of 1993, when the NASA astronauts carried out the maintenance plan, that Hubble was shamed and sealed directly.

Photo: NASA astronauts Story Musgrave and Jeffrey Hoffman repair Hubble in space in December 1993. Image source: [15] several years of Hubble's failure made Webb's research and development team extremely cautious, Webb's launch date has been repeatedly delayed, and his budget has climbed all the way to $10 billion. Such caution is necessary because Webb's orbit is thousands of times higher than the Hubble orbit, reaching more than 1 million kilometers, much farther than the moon. Once something went wrong with Webb, it was impossible to send someone to repair it. From Webb's launch to work, it must perform 344 critical steps under the control of a ground engineer, and any mistake will declare it dead. Such caution and patience laid the most solid foundation for Webb's debut, that is, the pinnacle.

The fourth factor in Webb's strength is that engineers and scientists have developed a large number of new technologies. Webb is far more complex than all previous infrared space telescopes. In fact, it is more complex than all telescopes and is by far one of the most complex devices available to human beings.

Image: near-infrared camera (top) and mid-infrared equipment (bottom) above Webb. Photo Source: [16] because of its complexity, it is impossible for people to piece together only some previous technologies to achieve their goals, but need to constantly develop new technologies. From the design and manufacture of all its internal instruments, to the design, manufacture, folding and deployment of five-layer sunshades, to the folding and unfolding of the main part of the telescope, to the focus of each mirror, and so on, all these processes are challenging, so it takes a lot of wisdom and hard work for some of the smartest engineers and scientists in the world.

Photo: engineers and technicians inspect Webb's five-layer sunshade. Photo Source: [17] what is the enlightening significance of Webb? Webb's success is not only its own success, but also greatly stimulates people's confidence in other space telescope projects. More importantly, its success will enlighten us in many ways.

Webb's success first tells all people and teams who want to achieve great results the simplest truth: sufficient patience, carefulness and wisdom are the basic requirements to achieve great results. Not only Webb, but also the previous Laser interference gravitational Wave Observatory (Laser Interferometer Gravitational-Wave Observatory,LIGO), generations of physicists and engineers finally made it the first instrument in the world to detect gravitational waves.

Figure: the appearance of the ground part of the two devices of LIGO located in Livingston and Hanford. Photo Source: [18] Webb's success is further proof of the value of Big Science. Over the past hundred years, the cost of scientific research related to observation and experiment has become higher and higher, and the team serving it has become larger and large. it is not uncommon for a laboratory to involve hundreds or even thousands of people. this has led science to the era of great science.

In the fierce competition in science and technology, different countries are faced with a difficult choice: to choose low-risk and safe projects or large-scale scientific projects with high risks and high returns? This poses a challenge to a country's decision-making in the field of science and technology. Webb's success has given people more confidence in big science projects that are full of risks and hopes.

Webb's success also sets a benchmark for more ambitious goals. In the future, people can use better vehicles to launch larger infrared space telescopes and observe other bands of space telescopes.

We hope that the data obtained by Webb in the next decade will reshape human understanding of celestial bodies in the solar system and the formation mechanism of the solar system, and deepen human understanding of exoplanets and extraterrestrial life, galaxies, the formation and explosion of various celestial bodies, and the universe itself. We also hope that in the future, there will be more powerful telescopes than Webb to travel into space, so that the human knowledge system can be further sublimated.

Photo: the last time humans see Webb. Photo Source: [19] Notes

[note 1] the Chinese article (https://mp.weixin.qq.com/ s / I6kBfXwS24dDSG3le65zWg) on the official account of Science magazine called Webb "NASA's new star space telescope", which is not rigorous, because Webb is not owned by NASA alone, but is jointly funded by NASA, ESA and CSA.

[note 2] Webb discovered the first supernova AT2022owj on June 22, 2022.

[note 3] for example, the magnitude of the AT 2022qmm it found when it was discovered was 24.1, which is much darker than the limit that most other telescopes can see (usually not darker than magnitude 21).

[note 4] the reason why people do not send radio telescopes into space is that most radio telescopes are basically unaffected by the atmosphere on the ground, and a few demanding radio telescopes work well in dry plateau desert areas. In addition, radio telescopes need a much larger aperture to achieve the same resolution as optical telescopes, and previously and currently, it was unrealistic to launch dozens of meters of radio telescopes into space.

References / picture sources

[1] https://www.nature.com/immersive/d41586-022-04185-3/index.html

[2] https://www.science.org/content/article/breakthrough-2022#section_breakthrough

[3] Northrop Grumman

[4] IMAGE: NASA, ESA, CSA, M. Zamani (ESA/Webb), Leah Hustak (STScI), SCIENCE: Brant Robertson (UC Santa Cruz), S. Tacchella (Cambridge), E. Curtis-Lake (UOH), S. Carniani (Scuola Normale Superiore), JADES Collaboration

[5] ESA/Webb, NASA & CSA, L. Armus, A. S. Evans

[6] SCIENCE: NASA, ESA, CSA, STScI,IMAGE PROCESSING: Joseph DePasquale (STScI), Anton M. Koekemoer (STScI), Alyssa Pagan (STScI) (left); SCIENCE: NASA, ESA, CSA, STScI,IMAGE PROCESSING: Joseph DePasquale (STScI), Alyssa Pagan (STScI) (right)

[7] IMAGE: NASA, ESA, CSA, STScI,IMAGE PROCESSING: Joseph DePasquale (STScI), Naomi Rowe-Gurney (NASA-GSFC)

[8] DSS;NASA/ESA/CSA, A. Carter (UCSC), the ERS 1386 team, and A. Pagan (STScI)

[9] IMAGE: STScI,3D MODEL: NASA, ESA, STScI

[10] NASA / JPL-Caltech (left), NASA / ESA / CSA / STScI (right)

[11] NASA, ESA, CSA, STScI,SCIENCE: Megan Reiter (Rice University), IMAGE PROCESSING: Joseph DePasquale (STScI), Anton M. Koekemoer (STScI).

[12] NASA/JPL

[13] NASA/MSFC/David Higginbotham

[14] NASA

[15] NASA

[16] Lockheed Martin (top); Science and Technology Facilities Council (bottom)

[17] Northrop Grumman Aerospace Systems

[18] https://www.ligo.caltech.edu/LA

[19] NASA, ESA

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