From “The Harvard Gazette” : “Telescope to help tell the story of the universe”
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December 16, 2021 [Brought forward today.]
Juan Siliezar
Harvard astrophysicist on the James Webb Telescope
Astrophysicist explains why the James Webb Telescope is NASA’s most ambitious space probe to date.
Full-scale model at South by Southwest in Austin. Credit: Chris Gunn/NASA.
NASA is set for another Apollo moment with the launch of its new James Webb Space Telescope as early as Dec. 24, barring complications. Billed as NASA’s most ambitious telescope to date, its purpose is to fundamentally alter our understanding of the universe.
Light takes time to travel. The nearest star to Earth is four light-years away, so the image we see of it is actually four years old. The new $10 billion instrument is so powerful it will allow us to see farther, essentially to look back in time to see how the first stars and galaxies came into existence. It will also let us peer into the atmospheres of exoplanets — some of which are potentially habitable — as they pass before stars. The light filtering through the atmosphere will leave telltale signs of the atmospheric components.
Mercedes López-Morales, a lecturer in the Department of Astronomy and an astrophysicist at the Center for Astrophysics | Harvard & Smithsonian, will be among the first researchers to use the Webb as part of a project to observe more than a dozen small planets during the telescope’s first cycle. The Gazette spoke to López-Morales about the new telescope, which was named after the former NASA administrator who led the agency through the Apollo missions, and why it has the scientific community so excited. The interview has been edited for clarity and length.
Q&A Mercedes López-Morales
GAZETTE: Can you talk about the mission of the Webb telescope?
LÓPEZ-MORALES: The James Webb Telescope is the most important flagship space mission ever built. It’s considered the successor of the Hubble Space Telescope, which was launched more than 30 years ago and completely changed the way we understand how the universe works at ultraviolet, visible, and near-infrared wavelengths. Unlike visible light, ultraviolet and infrared light are hidden from the human eye, and we need special detectors to “see” them. They hold the secrets of primordial galaxies and the chemical composition of outer space, as well as nearby planets. The capabilities of the James Webb will take us beyond what we learned with Hubble by further opening our eyes to the infrared universe. We’ll be able to study how the universe looked at the beginning and determine when the first galaxies and stars formed. We will also be able to study how and where in our galaxy stars and planets are forming right now, and, for the first time, to study what the atmospheres of exoplanets are made of and how similar or different the atmospheres of exoplanets are from the atmospheres of planets in our own solar system.
[2] Jake Lewis of the manufacturer Ball Aerospace is reflected in the telescope’s flight mirrors. Credit: David Higginbotham/Emmett Given/Ball Aerospace/NASA/MSFC/
GAZETTE: What makes the Webb the most ambitious space probe NASA’s ever built?
LÓPEZ-MORALES: A number of things. NASA has been building this telescope for 25 years. It’s hard to tell, but just as a ballpark, I would say thousands of scientists and engineers have worked on it. Maybe the biggest reason is that there are many technological advancements that are being used for the first time on a space telescope.
GAZETTE: What are some of those?
LÓPEZ-MORALES: One of the most spectacular is the primary mirror that is 6.5-meters in diameter [more than 21 feet], making it the largest telescope mirror ever launched into space. To make it possible to fit such a large mirror into the launch vehicle, engineers had to figure out a completely new way to build mirrors. They split them into a number of hexagonal pieces, each one with its own specific shape so that they could be folded for launch and then once in space they unfold and latch together like pieces of a puzzle into this massive and beautiful mirror painted with a very thin layer of gold with basically no gaps between the pieces.
GAZETTE: The mirror is a very crucial piece of this telescope?
LÓPEZ-MORALES: I always tell people that the mirror is like a bucket. The bigger the bucket, the more data you can collect. That translates into you seeing and collecting more light — both visible and the not-so-visible. Basically, you can push farther into the universe and further back in time.
Social Media Short: Webb Mirror Beauty.
GAZETTE: What else amazes you about the telescope?
LÓPEZ-MORALES: I would say the sunshield. There are two key requirements for the telescope to be able to produce high-quality observations. It has to be kept cold, at a stable temperature of about minus 200 degrees Celsius [minus 328 degrees Fahrenheit], and it has to be prevented from getting blinded by sunlight. The sunshield takes care of those requirements by shielding the telescope from the sun’s light and heat.
It’s a technological masterpiece. It’s made out of five very thin layers coated with aluminum, so they reflect the light from the sun. Each layer is like a sail. At launch, the sunshield is folded in, in a similar way as the telescope’s mirror is, and once in space the sunshield unfolds to a size of about a tennis court.
GAZETTE: Can you talk about your work with the telescope so far, and what’s upcoming?
LÓPEZ-MORALES: One of my main research interests is understanding the atmospheres of exoplanets, which are planets we have been discovering orbiting around nearby stars for more than two decades now. We have discovered a few thousand exoplanets now, and with that number we can, for the first time, start looking into answering a number of questions that weren’t possible to answer before. I am part of teams that will for the first time search the atmospheres of a number of exoplanets in the infrared to search for molecular species such as methane, ammonia, and carbon, magnesium, and silicate compounds. We cannot detect these with current telescopes, including Hubble. The presence or absence of such chemical species will tell if the planets have atmospheres at all, and if they do, what they are made of and how they compare to the make-up of similar planets in the solar system.
GAZETTE: What’s your biggest hope for this telescope?
LÓPEZ-MORALES: I hope that it helps us discover things that we had not thought about since that is how many of the major breakthroughs in science happen. You open a new window and discover that there is a lot of new information there that we had not considered. I also hope that the discoveries will inspire younger generations in the same way that the Hubble images inspired many of us who are now scientists and engineers.
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Harvard University is the oldest institution of higher education in the United States, established in 1636 by vote of the Great and General Court of the Massachusetts Bay Colony. It was named after the College’s first benefactor, the young minister John Harvard of Charlestown, who upon his death in 1638 left his library and half his estate to the institution. A statue of John Harvard stands today in front of University Hall in Harvard Yard, and is perhaps the University’s bestknown landmark.
Harvard University has 12 degree-granting Schools in addition to the Radcliffe Institute for Advanced Study. The University has grown from nine students with a single master to an enrollment of more than 20,000 degree candidates including undergraduate, graduate, and professional students. There are more than 360,000 living alumni in the U.S. and over 190 other countries.
The Massachusetts colonial legislature, the General Court, authorized Harvard University (US)’s founding. In its early years, Harvard College primarily trained Congregational and Unitarian clergy, although it has never been formally affiliated with any denomination. Its curriculum and student body were gradually secularized during the 18th century, and by the 19th century, Harvard University (US) had emerged as the central cultural establishment among the Boston elite. Following the American Civil War, President Charles William Eliot’s long tenure (1869–1909) transformed the college and affiliated professional schools into a modern research university; Harvard became a founding member of the Association of American Universities in 1900. James B. Conant led the university through the Great Depression and World War II; he liberalized admissions after the war.
The university is composed of ten academic faculties plus the Radcliffe Institute for Advanced Study. Arts and Sciences offers study in a wide range of academic disciplines for undergraduates and for graduates, while the other faculties offer only graduate degrees, mostly professional. Harvard has three main campuses: the 209-acre (85 ha) Cambridge campus centered on Harvard Yard; an adjoining campus immediately across the Charles River in the Allston neighborhood of Boston; and the medical campus in Boston’s Longwood Medical Area. Harvard University’s endowment is valued at $41.9 billion, making it the largest of any academic institution. Endowment income helps enable the undergraduate college to admit students regardless of financial need and provide generous financial aid with no loans The Harvard Library is the world’s largest academic library system, comprising 79 individual libraries holding about 20.4 million items.
Harvard University has more alumni, faculty, and researchers who have won Nobel Prizes (161) and Fields Medals (18) than any other university in the world and more alumni who have been members of the U.S. Congress, MacArthur Fellows, Rhodes Scholars (375), and Marshall Scholars (255) than any other university in the United States. Its alumni also include eight U.S. presidents and 188 living billionaires, the most of any university. Fourteen Turing Award laureates have been Harvard affiliates. Students and alumni have also won 10 Academy Awards, 48 Pulitzer Prizes, and 108 Olympic medals (46 gold), and they have founded many notable companies.
Colonial
Harvard University was established in 1636 by vote of the Great and General Court of the Massachusetts Bay Colony. In 1638, it acquired British North America’s first known printing press. In 1639, it was named Harvard College after deceased clergyman John Harvard, an alumnus of the University of Cambridge(UK) who had left the school £779 and his library of some 400 volumes. The charter creating the Harvard Corporation was granted in 1650.
A 1643 publication gave the school’s purpose as “to advance learning and perpetuate it to posterity, dreading to leave an illiterate ministry to the churches when our present ministers shall lie in the dust.” It trained many Puritan ministers in its early years and offered a classic curriculum based on the English university model—many leaders in the colony had attended the University of Cambridge—but conformed to the tenets of Puritanism. Harvard University has never affiliated with any particular denomination, though many of its earliest graduates went on to become clergymen in Congregational and Unitarian churches.
Increase Mather served as president from 1681 to 1701. In 1708, John Leverett became the first president who was not also a clergyman, marking a turning of the college away from Puritanism and toward intellectual independence.
19th century
In the 19th century, Enlightenment ideas of reason and free will were widespread among Congregational ministers, putting those ministers and their congregations in tension with more traditionalist, Calvinist parties. When Hollis Professor of Divinity David Tappan died in 1803 and President Joseph Willard died a year later, a struggle broke out over their replacements. Henry Ware was elected to the Hollis chair in 1805, and the liberal Samuel Webber was appointed to the presidency two years later, signaling the shift from the dominance of traditional ideas at Harvard to the dominance of liberal, Arminian ideas.
Charles William Eliot, president 1869–1909, eliminated the favored position of Christianity from the curriculum while opening it to student self-direction. Though Eliot was the crucial figure in the secularization of American higher education, he was motivated not by a desire to secularize education but by Transcendentalist Unitarian convictions influenced by William Ellery Channing and Ralph Waldo Emerson.
20th century
In the 20th century, Harvard University’s reputation grew as a burgeoning endowment and prominent professors expanded the university’s scope. Rapid enrollment growth continued as new graduate schools were begun and the undergraduate college expanded. Radcliffe College, established in 1879 as the female counterpart of Harvard College, became one of the most prominent schools for women in the United States. Harvard University became a founding member of the Association of American Universities in 1900.
The student body in the early decades of the century was predominantly “old-stock, high-status Protestants, especially Episcopalians, Congregationalists, and Presbyterians.” A 1923 proposal by President A. Lawrence Lowell that Jews be limited to 15% of undergraduates was rejected, but Lowell did ban blacks from freshman dormitories.
President James B. Conant reinvigorated creative scholarship to guarantee Harvard University (US)’s preeminence among research institutions. He saw higher education as a vehicle of opportunity for the talented rather than an entitlement for the wealthy, so Conant devised programs to identify, recruit, and support talented youth. In 1943, he asked the faculty to make a definitive statement about what general education ought to be, at the secondary as well as at the college level. The resulting Report, published in 1945, was one of the most influential manifestos in 20th century American education.
Between 1945 and 1960, admissions were opened up to bring in a more diverse group of students. No longer drawing mostly from select New England prep schools, the undergraduate college became accessible to striving middle class students from public schools; many more Jews and Catholics were admitted, but few blacks, Hispanics, or Asians. Throughout the rest of the 20th century, Harvard became more diverse.
Harvard University’s graduate schools began admitting women in small numbers in the late 19th century. During World War II, students at Radcliffe College (which since 1879 had been paying Harvard University professors to repeat their lectures for women) began attending Harvard University classes alongside men. Women were first admitted to the medical school in 1945. Since 1971, Harvard University has controlled essentially all aspects of undergraduate admission, instruction, and housing for Radcliffe women. In 1999, Radcliffe was formally merged into Harvard University.
21st century
Drew Gilpin Faust, previously the dean of the Radcliffe Institute for Advanced Study, became Harvard University’s first woman president on July 1, 2007. She was succeeded by Lawrence Bacow on July 1, 2018.
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