Archive for month: January, 2018

By Stuart Wolpert

The moon was formed from a violent, head-on collision between the early Earth and a “planetary embryo” called Theia approximately 100 million years after the Earth formed, almost 4.5 billion years ago, UCLA geochemists and colleagues reported in the journal Science.

Scientists knew about this high-speed crash, but many thought the Earth collided with Theia at an angle of approximately 45 degrees or more — a powerful sideswipe. New evidence substantially strengthens the case for a head-on assault.

The researchers analyzed seven rocks brought to the Earth from the moon by NASA missions Apollo 12, 15 and 17. They alsoanalyzed six volcanic rocks from the Earth’s mantle — five from Hawaii and one from Arizona.

How were they able to reconstruct the giant impact? The key to their detective work was a chemical signature revealed in oxygen atoms. (Rocks are 90 percent oxygen by volume, comprising half their weight.) Most oxygen atoms contain eight protons and eight neutrons and are represented by the symbol 16O. More than 99.9 percent of Earth’s oxygen is 16O, but heavier oxygen isotopes (variants) exist in trace amounts: 17O, with one extra neutron, and 18O, with two extra neutrons.

The Earth, Mars and other planetary bodies in our solar system each have a unique ratio of 17O to 16O — a distinctive fingerprint. A team of scientists from Germany reported last year in Science that the Earth and moon have different ratios of oxygen isotopes too.
The new research finds that is not the case.

“We don’t see any difference between the Earth and the moon’s oxygen isotopes; they’re indistinguishable,” said lead author Edward Young, professor of geochemistry and cosmochemistry.

Young’s research team used state-of-the-science technology and techniques to make extraordinarily precise and careful measurements, and verified them with UCLA’s new, larger mass spectrometer.

What does the absence of unique chemical signatures between the Earth and moon reveal? If the Earth and Theia had collided in a glancing side blow, the vast majority of the moon would have been made mainly of Theia, and the Earth and moon should have different oxygen isotopes, Young said. A head-on collision, however, likely would have produced a thorough mixing of the Earth and Theia — both in the Earth and the moon, he said.

“Theia was thoroughly mixed into both the Earth and the moon, and evenly dispersed between them,” Young said. “This explains why we don’t see a different signature of Theia in the moon versus the Earth. A glancing blow would not be consistent with this.”

Theia, which did not survive the collision (except as a large part of the Earth and moon) was growing and probably would have become a planet if the crash had not occurred, Young said. Theia was probably similar in size to the Earth, he believes.

The core of Theia and the core of the early Earth merged to form the Earth’s iron core, he said. The moon is approximately 100 times less massive than the Earth.

Co-authors of the Science paper are Issaku Kohl, a UCLA researcher in Young’s laboratory; Paul Warren, a UCLA researcher in the Department of Earth, Planetary, and Space Sciences; David Rubie, a research professor with Germany’s Bayerisches Geoinstitut, University of Bayreuth; and Seth Jacobson and Alessandro Morbidelli, planetary scientists with France’s Laboratoire Lagrange, Université de Nice.

The research was funded by NASA, the Deep Carbon Observatory and the European Research Council Advanced Grant ACCRETE.

The moon is older than scientists thought

Young is part of another UCLA-led research team that reported the moon is significantly older than some scientists believe. Their precise analysis of zircons bought to Earth by
Apollo 14 astronauts reveals the moon is at least 4.51 billion years old and probably formed only about 60 million years after the birth of the solar system — 40 to 140 million years earlier than recently thought.

Despite many scientific attempts, using a variety of techniques, the age of the moon has never been accurately determined and remains hotly debated among scientists.

“We have finally pinned down a minimum age for the moon; it’s time we knew its age and now we do: 4.51 billion years old,” said Mélanie Barboni, lead author and a research geochemist with the Department of Earth, Planetary, and Space Sciences.

“Whatever was there before the giant impact with Theia has been erased,” Barboni said. “It’s important to know when Earth started its evolution.”

The early Earth likely had many large colli-sions over its first 60 million years, Young said.

Barboni analyzed eight pristine zircons from two rocks and samples of soil brought to the Earth from the moon by the Apollo 14 mission. From most moon rocks, it is very difficult to determine their formation ages
because they contain a patchwork of fragments of multiple rocks.

“Zircons are nature’s best clocks,” said Kevin McKeegan, co-author and a professor of geochemistry and cosmochemistry in the Department of Earth, Planetary, and Space Sciences. “The most ancient pieces of the Earth that we have are zircons, which are the best mineral in preserving geological history and revealing where they originated.”

“Zircons are the best mineral at giving up their secrets,” Young said. “They can’t keep a secret.”

The researchers in effect used two clocks with high precision, the first time this has been achieved to date the age of the moon. In the zircons, they analyzed the chemical elements uranium-lead (uranium decays to lead) and lutetium-hafnium (lutetium decays to hafnium). This research was reported in the journal Science Advances.

The Earth’s collision with Theia created a liquefied moon, which then solidified. Scientists believe most of the moon’s surface was covered with magma right after its formation. The uranium-lead measurements reveal when the zircons first appeared in the moon’s initial magma ocean, which later cooled down and formed the moon’s mantle and crust; the lutetium-hafnium measurements reveal an earlier event: when its magma formed.

“Together, they tell us the whole story,” Barboni said. “The pieces now fit together.”

Earlier research on the moon has been based on moon rocks that were contaminated by multiple collisions. “They dated some event, but not the age of the moon,” McKeegan said of some previous researchers.

Co-authors are Patrick Boehnke, a former UCLA graduate student in Professor Mark Harrison’s laboratory and now a University of Chicago postdoctoral scholar; Christopher Keller, a former Princeton University graduate student who is now a UC Berkeley postdoctoral scholar; Issaku Kohl, a research geochemist in Young’s laboratory; and Blair Schoene, associate professor of geosciences at Princeton University.

The research was funded by NASA, and Barboni received support from the Swiss National Science Foundation.

UCLA geochemists led by Harrison reported in 2015 that life likely existed on Earth at least 4.1 billion years ago, shortly after the planet formed — and that rather than being dry and desolate, the early Earth was probably much more like it is today than was previously thought.

Harrison’s research indicating the early Earth was wetter and cooler than scientists used to think fits much better with the 60-million-year date for the moon than a 200-million-year date would fit.

By Jessica Wolf

UCLA’s William Andrews Clark Memorial Library will officially reopen Jan. 21, restoring public access to the university’s renowned collection of rare books and manuscripts from England’s Tudor period through the 18th century, including a large repository of materials related to Oscar Wilde.

An architectural and archival treasure surrounded by the constantly evolving West Adams neighborhood of Los Angeles, the William Andrews Clark Memorial Libraryhas been closed for more than two years fora major seismic retrofit and to bring the historic building into compliance with the federal Americans with Disabilities Act.

“The Clark is a gem and now we are letting the world know that we have restored this beautiful treasure for the 21st century, and we are going to continue to take care of it,” said Helen Deutsch, the new director of UCLA’s Center for 17th- and 18th-Century Studies and the Clark Library. Deutsch has always considered the Clark her intellectual home, having first arrived there as an Ahmanson-Getty postdoctoral fellow to work on a book about Alexander Pope.

The ribbon-cutting ceremony will include a poetry reading by Maximillian Novak, professor emeritus of English; 18th century- themed desserts made from recipes curated from the library’s collection; and maybe even some croquet on the lawn, a favorite activity of prominent philanthropist and collector William Andrews Clark Jr., who bequeathed the library to UCLA in 1934.

Clark librarians are also putting together an exhibit highlighting the history of the Clark, featuring archival photos and documents from the collection, which will be on display for the grand reopening.

Culmination of two years of work

Retrofitting a building on the California historic registry was a massive undertaking requiring some creative problem solving. Contractors had to drill down through the roof to reinforce the building with earthquake-safe rebar. For part of the exterior of the new pavilion, they found the original brick maker, who was able to replicate the historic brickwork and unique lavender grout that is a signature of the original building. Much of the electrical system also had to be upgraded.

The project included major reinforcements for earthquake safety, as well as reallocating office spaces and building a new pavilion that allows space for an elevator and ramps that improve access for people with disabilities.

Clark staff and UCLA architects took the opportunity to make other changes as well, adding Wi-Fi access to all spaces, buildingan expanded annex to store the library’s burgeoning collection, constructing a new orientation room to introduce scholars and visitors to the Clark’s services, as well as creating a fully equipped smart classroom to facilitate interactions with the collections by students, faculty and other researchers.

Open doors

The space has been sorely missed by scholars in the 17th- and 18th-century studies community, Deutsch said. She is eager to work with faculty to restore the number of fellows who work on site to pre-closure levels.

“The thing that makes the Clark very special and part of UCLA, and unlike a place like the Huntington, is that the Clark is open to the public,” she said. “Anyone can come and work here. We are open to students of any level as well as to amateur scholars, and you don’t have to have a university affiliation. We really are looking forward to welcoming everyone back.”

With the support of generous donors, staff also took the opportunity to undertake a variety of cleaning and restoration projects including the intricately painted ceilings in the Clark’s vestibule, and the two large decorative stone urns and four fountains on the grounds. A 1930s sun dial was also repaired and now hangs prominently on the new building. A new, airier lounge area for visiting scholars will be named in honor of beloved Professor Novak, who has been a fixture at the Clark for decades.

Preservation of the collections

Deutsch said she plans to continue prioritizing access, preservation and conservation of the 1926 building as well as its eclectic and prolific collections of artwork, rare books and manuscripts.

Deutsch said, “We have so much valuable material at the Clark. The art collection alone has never been fully cataloged, and a grant from the Mellon Foundation will let us begin doing that right away.”

Finishing touches are still underway, but some of the much-loved Clark events have already begun anew on site, including an October chamber music performance from the Lincoln Trio. An opera based on Jane Austen’s “Mansfield Park,” specially created for the Clark and directed by Peter Kazaras, director of Opera UCLA, was performed in June. The Clark’s monthly classical performances are back for the 2017-2018 season.

“There was a palpable sense of excitement for people to get back on the property,” Deutsch said.

As of August, the Clark also has a new head librarian, Anna Chen, who fell in love with the Clark at first sight.

“My first library job was to catalog 17th- and 18th-century bound manuscripts, which gave me a solid grounding and love for this time period,” Chen said. “Joining the Clark is such a privilege and, in some ways, a homecoming for me to shepherd the same kinds of holdings that first inspired me to become a librarian.”

Chen also is starting to think about other ways to enhance the visitor experience and effectiveness of the space, including seeking out sustainability experts at UCLA to discuss ways to manage the nearly five acres of gardens and lawns, Deutsch said.

Chen and Deutsch, along with Head of Research Services Philip Palmer and Manu-scripts and Archives Librarian Rebecca Fenning Marschall, are also keen to expand the Clark’s digitization and digital humanities efforts. A recent grant from the National Endowment for the Humanities provided $261,000 to produce digital facsimiles of 279 annotated volumes from the hand-press era (ca. 1455–1830) and make them freely available online.

Deutsch would also like to see more fellowship opportunities for grad students who are interested in librarianship.

“We have such great examples in Phil and Anna, both of whom hold Ph.D.s in literature, of how librarianship and literary studies energize each other,” she said. “Librarianship itself takes a lot of intellectual creativity and imagination.”