Let There Be Light: Finding the Earliest Galaxies

Watson Lecture Preview

Richard S. Ellis, the Steele Family Professor of Astronomy, is on the verge of seeing as far back as it is possible to see—not quite back to the dawn of time itself but to the dawn of the first galaxies. He describes the journey at 8 p.m. on Wednesday, October 16, in Caltech's Beckman Auditorium. Admission is free.

 

Q: What do you do?

A: I study distant galaxies. When we look deep into space with the Hubble Space Telescope and at the W. M. Keck Observatory, we're looking back in time. I'm trying to look back to the moment the very first stars switched on—to the "cosmic dawn." Before then, there was no starlight, and we call that period the Dark Ages.

The universe today is 13.8 billion years old, and we can now look about 97 percent of the way back to the Big Bang. We think we need to look maybe another half-percent farther back, or about another 100 million years, in order to find the very earliest objects. We will do this with a large telescope called the Thirty Meter Telescope, which should begin construction in April, and the James Webb Space Telescope, which, I hope, will be launched in 2018.

The very first stars would only contain hydrogen and helium, and we will be able to recognize them by their colors and spectra. Our models tell us that such objects, free from heavy elements such as magnesium and iron, should be extraordinarily blue.

You might ask, "Why is this important?" And the answer is that, in many ways, we're searching for our origins. Stars produced the elements that make up you and me and everything else around us. We are, in a sense, stardust. The discovery of the microwave background radiation from the Big Bang was a big milestone in cosmic history. The moment when the universe switched on its starlight—cosmic dawn—is another important milestone.

 

Q: What is the best thing about what you do?

A: Above all, I like observing with large telescopes; it's inspirational to search for objects that are extraordinarily distant. And I like working with graduate students; it's remarkable that Caltech students can accompany me to the telescope and share in the discoveries.

 

Q: How did you get into this line of work?

A: I became convinced I wanted to be an astronomer when I was six years old. I grew up in Wales, and our public library had a little book called Out Into Space by the late Sir Patrick Moore, the famous popularizer of astronomy. It was about a boy and girl who went to their eccentric uncle's house, and he had a telescope. That hooked me. I never wanted to do anything else. Forty years later, I appeared on his television program, The Sky at Night, and he gave me a signed copy. And when I reread it, I still remembered the relevant chapters.

 

Q: So, do you now qualify as an eccentric uncle yourself?

A: I do, yeah [laughter]. I am an uncle, and I definitely am eccentric. You can ask my sister's kids [more laughter].

 

Named for the late Caltech professor Earnest C. Watson, who founded the series in 1922, the Watson Lectures present Caltech and JPL researchers describing their work to the public. Many past Watson Lectures are available online at Caltech's iTunes U site.

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Douglas Smith
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Watson Lecture: Let There Be Light: Finding the Earliest Galaxies
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Caltech Named World's Top University in Times Higher Education Global Ranking

For the third year in a row, the California Institute of Technology has been rated the world's number one university in the Times Higher Education global ranking of the top 200 universities.

Harvard University, Oxford University, Stanford University, and the Massachusetts Institute of Technology round out the top five schools in the 2013–2014 rankings.

Times Higher Education compiled the listing using the same methodology as in the 2011–2012 and 2012–2013 surveys. Thirteen performance indicators representing research (worth 30 percent of a school's overall ranking score), teaching (30 percent), citations (30 percent), international outlook (which includes the total numbers of international students and faculty and the ratio of scholarly papers with international collaborators, 7.5 percent), and industry income (a measure of innovation, 2.5 percent) make up the data. The data were collected, analyzed, and verified by Thomson Reuters.

The Times Higher Education site has the full list of the world's top 400 schools and all of the performance indicators.

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Kathy Svitil
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Caltech to Offer Online Courses through edX

To expand its involvement in online learning, the California Institute of Technology will offer courses through the online education platform edX beginning this October.

The edX course platform is an online learning initiative launched in 2012 by founding partners Harvard University and the Massachusetts Institute of Technology (MIT). Caltech's rigorous online course offerings will join those of 28 other prestigious colleges and universities in the edX platform's "xConsortium."

This new partnership with edX comes one year after Caltech offered three courses through the online learning platform Coursera in fall 2012. The Institute will now offer courses through both platforms.

"Coursera and edX have some foundational differences which are of interest to the faculty," says Cassandra Horii, director of teaching and learning programs at Caltech. Both organizations offer their courses at no cost to participating students; edX, however, operates as a nonprofit and plans to partner with only a small number of institutions, whereas Coursera—a for-profit, self-described "social entrepreneurship company"—partners with many institutions and state university systems.

The two platforms also emphasize different learning strategies, says Horii. "Coursera has a strong organizational principle built around lectures, so a lot of the interactivity is tied right into the video," she says. Though edX still enables the use of video lectures, a student can customize when he or she would like to take quizzes and use learning resources. In addition, edX allows faculty to embed a variety of learning materials—like textbook chapters, discussions, diagrams, and tables—directly into the platform's layout.

In the future, data collected from both platforms could provide valuable information about how students best learn certain material, especially in the sciences. "Caltech occupies this advanced, really rigorous scientific education space, and in general our interest in these online courses is to maintain that rigor and quality," Horii says. "So, with these learning data, we have some potential contributions to make to the general understanding of learning in this niche that we occupy."

Even before joining edX and Coursera, Caltech had already become an example in the growing trend of Massive Open Online Courses (MOOCs). Yaser Abu-Mostafa, professor of electrical engineering and computer science, developed his own MOOC on machine learning, called "Learning from Data," and offered it on YouTube and iTunes U beginning in April 2012.

Since its debut, Abu-Mostafa's MOOC has reached more than 200,000 participants, and it received mention in the NMC Horizon Report: 2013 Higher Education Edition—the latest edition of an annual report highlighting important trends in higher education. The course will be offered again in fall 2013 on iTunes U, and is now also open for enrollment in edX.

Although Caltech is now actively exploring several outlets for online learning, the Institute's commitment to educational outreach is not a recent phenomenon. In the early 1960s, Caltech physicist Richard Feynman reorganized the Institute's introductory physics course, incorporating contemporary research topics and making the course more engaging for students. His lectures were recorded and eventually incorporated into a widely popular physics book, The Feynman Lectures on Physics, which has sold millions of copies in a dozen languages.

Continuing in the tradition set by Feynman, the MOOCs at Caltech seek to provide a high-quality learning environment that is rigorous but accessible. "No dumbing down of courses for popular consumption . . . no talking over people's heads either; at Caltech, we explain things well because we understand them well," adds Abu-Mostafa.

More information on Caltech's online learning opportunities is available on the Online Education website.

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Friday, October 4, 2013

Undergraduate Teaching Assistant Orientation

Monday, August 12, 2013
Cahill, Hameetman Auditorium – Cahill Center for Astronomy and Astrophysics

Magnetic Fields: A Window to a Planet's Interior and Habitability

Thirty Meter Telescope Project Partners Sign Master Agreement

Document formalizes Caltech’s collaboration among several other international institutions.

Scientific authorities on the Thirty Meter Telescope (TMT) project announced on Friday that they have now signed a master agreement formalizing project goals and providing a governing framework for the international collaboration. TMT is a partnership among Caltech, the University of California, and a number of astronomical observatories and institutions from Canada, China, India, and Japan.

The agreement establishes an official commitment among the partners and delineates the rights and obligations of its global collaborators. These measures are intended to ensure steady progress for the TMT, which is planned to start construction in April 2014 and begin scientific operations in 2022.

"We are pleased with this vote of confidence from the scientific authorities," said Edward Stone, the David Morrisroe Professor of Physics and vice provost for special projects at Caltech, and vice chair of the TMT Board. "Their signing of this master agreement is a key endorsement of TMT's scientific merits as well as the project's overall implementation plan."

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Thursday, September 26, 2013

Graduate TA Orientation & Teaching Conference

Friday, July 19, 2013
Cahill, Hameetman Auditorium – Cahill Center for Astronomy and Astrophysics

"Are We Alone?" Public lecture by Dr. Jill Tarter

Voyager: Getting to Know the Magnetic Highway

Since last August, NASA's farthest-flung robotic envoy, Voyager I, has been exploring a distant region just shy of interstellar space, some 11 billion miles (18 billion kilometers) away. Now, in three new papers in Science Express, Voyager scientists, including Caltech's Ed Stone, are sharing what they have learned about the peculiar region known as the "magnetic highway."

In this unexpected region, energetic particles from inside the heliosphere—the "bubble" containing charged particles streaming away from the sun—have escaped and disappeared along a highway of magnetic field lines. Their disappearance has allowed Voyager to see even low-energy cosmic rays that are zipping into the heliosphere from interstellar space.

Stone, the David Morrisroe Professor of Physics at Caltech and the mission's project scientist since 1972, says that what's really interesting is that, although Voyager is still within the realm of the sun's magnetic field, the spacecraft is already getting a taste of what's outside the bubble.

"In this region, Voyager is providing us with a preview of what we're going to see once we reach interstellar space," Stone says. "We're no longer just measuring the high-energy cosmic rays that can get inside the bubble. We're now seeing lower energy cosmic rays as well. We believe we have gotten the first indication of what the total intensity of galactic cosmic rays is in nearby interstellar space."

For more on the findings, read the full NASA release.

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Kimm Fesenmaier
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Notes from the Back Row: "Quantum Entanglement and Quantum Computing"

John Preskill, the Richard P. Feynman Professor of Theoretical Physics, is hooked on quanta. He was applying quantum theory to black holes back in 1994 when mathematician Peter Shor (BS '81), then at Bell Labs, showed that a quantum computer could factor a very large number in a very short time. Much of the world's confidential information is protected by codes whose security depends on numerical "keys" large enough to not be factorable in the lifetime of your average evildoer, so, Preskill says, "When I heard about this, I was awestruck." The longest number ever factored by a real computer had 193 digits, and it took "several months for a network of hundreds of workstations collaborating over the Internet," Preskill continues. "If we wanted to factor a 500-digit number instead, it would take longer than the age of the universe." And yet, a quantum computer running at the same processor speed could polish off 193 digits in one-tenth of a second, he says. Factoring a 500-digit number would take all of two seconds.

While an ordinary computer chews through a calculation one bite at a time, a quantum computer arrives at its answer almost instantaneously because it essentially swallows the problem whole. It can do so because quantum information is "entangled," a state of being that is fundamental to the quantum world and completely foreign to ours. In the world we're used to, the two socks in a pair are always the same color. It doesn't matter who looks at them, where they are, or how they're looked at. There's no such independent reality in the quantum world, where the act of opening one of a matched pair of quantum boxes determines the contents of the other one—even if the two boxes are at opposite ends of the universe—but only if the other box is opened in exactly the same way. "Quantum boxes are not like soxes," Preskill says. (If entanglement sounds like a load of hooey to you, you're not alone. Preskill notes that Albert Einstein famously derided it back in the 1930s. "He called it 'spooky action at a distance,' and that sounds even more derisive when you say it in German—'Spukhafte Fernwirkungen!'")

An ordinary computer processes "bits," which are units of information encoded in batches of electrons, patches of magnetic field, or some other physical form. The "qubits" of a quantum computer are encoded by their entanglement, and these entanglements come with a big Do Not Disturb sign. Because the informational content of a quantum "box" is unknown until you open it and look inside, qubits exist only in secret, making them ideal for spies and high finance. However, this impenetrable security is also the quantum computer's downfall. Such a machine would be morbidly sensitive—the slightest encroachment from the outside world would demolish the entanglement and crash the system.

Ordinary computers cope with errors by storing information in triplicate. If one copy of a bit gets corrupted, it will no longer match the other two; error-detecting software constantly checks the three copies against one another and returns the flipped bit to its original state. Fixing flipped bits when you're not allowed to look at them seems an impossible challenge on the face of it, but after reading Shor's paper Preskill decided to give it a shot. Over the next few years, he and his grad student Daniel Gottesman (PhD '97) worked on quantum error correction, eventually arriving at a mathematical procedure by which indirectly measuring the states of five qubits would allow an error in any one of them to be fixed.

This changed the barriers facing practical quantum computation from insurmountable to merely incredibly difficult. The first working quantum computers, built in several labs in the early 2000s, were based on lasers interacting with what Preskill describes as "a handful" of trapped ions to perform "a modest number of [logic] operations." An ion trap is about the size of a thermos bottle, but the laser systems and their associated electronics take up several hundred square feet of lab space. With several million logic gates on a typical computer chip, scaling up this technology is a really big problem. Is there a better way? Perhaps. According Preskill, his colleagues at Caltech's Institute for Quantum Information and Matter are working out the details of a "potentially transformative" approach that would allow quantum computers to be made using the same silicon-based technologies as ordinary ones.

 "Quantum Entanglement and Quantum Computing" is available for download in HD from Caltech on iTunesU. (Episode 19)

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Douglas Smith
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