Tag Archive for James Greenwood

Gilmore Works on Planetarium Show at American Museum of Natural History

worlds beyond earthResearch conducted by a Wesleyan professor is part of a new space show at the American Museum of Natural History.

Martha Gilmore

Martha GIlmore.

Martha Gilmore, George I. Seney Professor of Geology and professor of Earth and environmental sciences, worked over the past year developing content for the new Hayden Planetarium Space Show Worlds Beyond Earth. The show opened on Jan. 21 as part of the museum’s 150th anniversary celebration.

“It’s amazing,” Gilmore says. “The images that you see are all realistic. We even contacted some of the engineers for the Magellan spacecraft in order to understand exactly how the spacecraft imaged Venus in the early 1990s.”

Featuring brilliant visualizations of distant worlds, groundbreaking space missions, and scenes depicting the evolution of our solar system, Worlds Beyond Earth “takes viewers on an exhilarating journey that reveals the surprisingly dynamic nature of the worlds that orbit our Sun and the unique conditions that make life on our planet possible,” according to the American Museum of Natural History’s website.

Over the year, Gilmore worked with fellow Earth and planetary scientists, science visualization experts, writers, and artists to turn data into a visual masterpiece displayed on the world’s most advanced planetarium projection system. Gilmore’s specific task was to share the story of Venus having once been a habitable planet.

“The idea that Mars, Venus, and Earth were all habitable four billion years ago, but only Earth remains—that’s what I presented to them, and it’s really nice to see that story in the most famous planetarium show in the country!”

Gilmore

Wesleyan alumnus Mark Popinchalk ’13 and Martha Gilmore mingled at the Worlds Beyond Earth preview event.

On Jan. 15, Gilmore was invited to the museum for a sneak preview of the show. Other Wesleyan affiliates in attendance included James Greenwood, assistant professor of Earth and environmental sciences; Anne Canty ’84, senior vice president for communications at the museum; and Gilmore’s former student and museum science educator Mark Popinchalk ’13.

Gilmore also is one of three scientists featured in a short movie that will be played in the waiting area of the planetarium.

The show “is just gorgeous,” Gilmore said. “What I appreciate now is that the data you see in the show are correct—the spacecraft orbits, the positions of the planets and stars, the magnetic field data, etc. It’s an incredible amount of work to make that happen. If you see it and wait for the credits to roll on the dome, you’ll see my name and Wesleyan!”

Herbst and Greenwood in The Conversation: The Tell-Tale Clue to How Meteorites Were Made

Wesleyan faculty frequently publish articles based on their scholarship in The Conversation US, a nonprofit news organization with the tagline, “Academic rigor, journalistic flair.” In a new article, John Monroe Van Vleck Professor of Astronomy Bill Herbst and Assistant Professor of Earth and Environmental Sciences James Greenwood write about the model they’ve proposed for how the most common kind of meteorites form—a mystery that has dogged scientists for decades.

The tell-tale clue to how meteorites were made, at the birth of the solar system

April 26, 1803 was an unusual day in the small town of L’Aigle in Normandy, France – it rained rocks.

Over 3,000 of them fell out of the sky. Fortunately, no one was injured. The French Academy of Sciences investigated and proclaimed, based on many eyewitness stories and the unusual look of the rocks, that they had come from space.

The Earth is pummeled with rocks incessantly as it orbits the Sun, adding around 50 tons to our planet’s mass every day. Meteorites, as these rocks are called, are easy to find in deserts and on the ice plains of Antarctica, where they stick out like a sore thumb. They can even land in backyards, treasures hidden among ordinary terrestrial rocks. Amateurs and professionals collect meteorites, and the more interesting ones make it to museums and laboratories around the world for display and study. They are also bought and sold on eBay.

Despite decades of intense study by thousands of scientists, there is no general consensus on how most meteorites formed. As an astronomer and a geologist, we have recently developed a new theory of what happened during the formation of the solar system to create these valuable relics of our past. Since planets form out of collisions of these first rocks, this is an important part of the history of the Earth.

This meteor crater in Arizona was created 50,000 years ago when an iron meteorite struck the Earth. It is about one mile across. W. Herbst, CC BY-SA

This meteor crater in Arizona was created 50,000 years ago when an iron meteorite struck the Earth. It is about one mile across. (Photo by Bill Herbst, CC BY-SA)

The mysterious chondrules

Study by Herbst, Greenwood Presents New Theory on How Meteorites Formed

A paper by John Monroe Van Vleck Professor of Astronomy William Herbst and Assistant Professor of Earth and Environmental Sciences James Greenwood will be published in the September 2019 issue of Icarus, published by Elsevier. The paper is available online.

The paper, titled “Radiative Heating Model for Chondrule and Chondrite Formation,” presents a new theory of how chondrules and chondrites (the most common meteorites) formed. It suggests a new approach to thinking about these rocks that populate the meteorite collections on Earth. It includes both theory and experiments (completed in Greenwood’s lab in Exley Science Center).

These laboratory experiments demonstrate that porphyritic olivine chondrules, the most voluminous type of chondrule, can be made using heating and cooling curves predicted by the “flyby” model. View a schematic diagram here.

“The problem of how chondrules and chondrites formed has been around for decades—more than a century, really. We cannot yet claim to have solved the problem but we have provided a new idea about the solution that passes many tests,” Herbst explained.

The basic idea, Herbst said, involves heating of small fluffy “rocks” in space as they fly past molten lava eruptions on larger asteroids, during the first few million years of the solar system’s existence.

Herbst, Greenwood, and Postdoctoral Research Associate Keniche Abe, will present this research at meetings this summer in Europe and Japan.

Students, Faculty, Alumni Present Research at 50th Annual Planetary Science Conference

Jeremy Brossier presented a talk titled "Radiophysical Behaviors of Venus’ Plateaus and Volcanic Rises: Updated Assessment." He also presented a poster titled "Complex Radar Emissivity Variations at Some Large Venusian Volcanoes."

At left, earth and environmental sciences postdoctoral research associate Jeremy Brossier presented a poster titled “Complex Radar Emissivity Variations at Some Large Venusian Volcanoes” during the Lunar and Planetary Science Conference in Texas.

Several Wesleyan students, faculty, and alumni attended the 50th Lunar and Planetary Science Conference (LPSC) March 18-22 in The Woodlands, Texas. Members of the Wesleyan Planetary Sciences Group presented their research on a range of planetary bodies.

This annual conference brings together international specialists in petrology, geochemistry, geophysics, geology, and astronomy to present the latest results of research in planetary science.

Earth and environmental studies major Emmy Hughes ’20 presented a poster titled “Observations of Transverse Aeolian Ridges in Digital Terrain Models” during a session on “Planetary Aeolian Processes.”

Earth and environmental science graduate student Reid Perkins MA ’19 presented a talk titled “A Reassessment of Venus’ Tessera Crater Population and Implications for Tessera Deformation” and a poster titled “Volumes and Potential Origins of Crater Dark Floor Deposits on Venus.”

Gilmore, Greenwood Recipients of NASA Grant to Map Venus’s Craters

Caption: Radar image of Venus. Alpha Regio tessera is partly covered by the dark parabola of the impact crater Stuart on the volcanic plains.

Professors Martha Gilmore and James Greenwood recently received a NASA grant to study crater parabolas on Venus using radar data. Pictured is a Magellan radar image of Venus. Alpha Regio tessera is partly covered by the dark parabola of the impact crater Stuart on the volcanic plains. (Photo courtesy of NASA)

Like planet Earth, the geology of Venus is diverse; consisting of areas of flat plains and deformed, mountain-like terrains called tesserae. And like Earth, Mars, and the Moon, Venus is checkered with hundreds of craters.

“What’s odd about Venus’s craters, is that craters we do see are relatively young, indicating the surface of Venus has been covered by planet-wide volcanic flows,” says Martha “Marty” Gilmore, George I. Seney Professor of Geology, professor of earth and environmental sciences. “The tesserae are the only terrains older than these volcanic flows and thus our only hope at accessing rocks from the first billion years of Venus’s history, when the planet may have had an ocean and may have been habitable.”

As the recipient of a three-year $430,801 grant from NASA’s Solar System Workings Program, Gilmore and James Greenwood, assistant professor of earth and environmental sciences, will use Magellan radar data to create the first map of crater ejecta on Venus classified by origin on plains or tessera terrain. Their project is titled “Radar Emissivity and Dielectric Permittivity of the Venus Surface Beneath Crater Parabolas.” Crater parabolas refer to the shape of the ejecta deposits as they are carried westward by the high-altitude Venus winds.

NSF Grant Supports Field-Emission Scanning Electron Microscope Purchase

Michelle Personick, assistant professor of chemistry, examines nanoparticles viewed from a new field emission scanning electron microscope.

Michelle Personick, assistant professor of chemistry, examines palladium nanoparticles viewed from a new field-emission scanning electron microscope.

The monitor on the left displays a backscattered electron image of a meteorite at 100x; the colored version, on the right and top monitor, is an elemental map of the same area of the sample. The new FE-SEM has the ability to magnify samples at up to 300,000x, whereas Wesleyan’s former SEM could only reliably magnify samples at 40,000x.

By using a newly acquired electron microscope, the E&ES 368 Meteorites and Cosmochemistry class was able to classify a meteorite discovered in Morocco.

“We were able to determine that it was an H4 ordinary chondrite, and the chemical information being collected today will be used to document these findings and submit this meteorite to the Meteorite Nomenclature Committee of the Meteoritical Society for official classification,” said class instructor Jim Greenwood, assistant professor of earth and environmental sciences.

On Feb. 8, several faculty, students and staff from Academic Affairs gathered in Exley Science Center to celebrate the arrival of the instrument and the opening of the newly-renovated lab that it is housed in. The lab is in the basement connector between Exley and Hall-Atwater.

On Feb. 8, several faculty, students and staff from Academic Affairs gathered in Exley Science Center to celebrate the arrival of the instrument and the opening of the newly renovated lab that it is housed in. The microscope is housed in the basement pathway between Hall-Atwater Laboratory and Shanklin and is part of the Advanced Instrumentation Center’s Scientific Imaging Laboratory.

Wesleyan acquired the field-emission scanning electron microscope (FE-SEM) with support from a $202,300 National Science Foundation grant awarded in August 2017. Greenwood and Michelle Personick, assistant professor of chemistry, applied for the grant through the NSF’s Major Research Instrumentation and Chemistry Research Instrumentation Programs. Wesleyan faculty Renee Sher, Martha Gilmore, Dana Royer, Ellen Thomas, Phil Resor, Suzanne O’Connell, Tim Ku, Johan “Joop” Varekamp and Ruth Johnson also contributed to the grant application.

“The SEM is a versatile tool that enables researchers to simultaneously obtain a wealth of different information about a sample, including topography, composition and fine structure,” Personick said. “At Wesleyan, the research enabled by the microscope addresses broad-ranging fundamental questions with significant societal relevance, including the sustainable production of chemicals and energy, the origin of the Earth’s oceans, and the relationship between atmospheric carbon dioxide levels and temperature in ancient environments.”

Faculty, Students Win Research Support from NASA’s CT Space Grant Consortium

The Van Vleck Observatory on Foss Hill.

The Van Vleck Observatory on Foss Hill.

Two faculty members and three students have been awarded grants in the latest call for proposals from NASA’s Connecticut Space Grant Consortium.

Jim Greenwood, assistant professor of earth and environmental sciences, and Bill Herbst, the John Monroe Van Vleck Professor of Astronomy, professor of integrative sciences, were awarded $8,000 for a Faculty Collaboration Grant titled “Chondrule Formation Experiments.” This is to run high-temperature experiments on material that makes up meteorites in order to test a hypothesis that they put forward in a recent paper in Icarus this year.

Seth Redfield, associate professor of astronomy, associate professor of integrative sciences, was awarded $1,500 for a STEM Education Programming Grant

Herbst, Greenwood Co-Author Article on Chondrules

Bill Herbst

Bill Herbst

Bill Herbst, the John Monroe Van Vleck Professor of Astronomy, and James Greenwood, assistant professor of earth and environmental sciences, co-authored an article published in the planetary science journal Icarus. Their article, “A New Mechanism for Chondrule Formation: Radiative Heating by Hot Planetesimals” grew out of research seminars from the recently introduced Planetary Science graduate concentration and minor at Wesleyan.

Their work focused on chondrules, or tiny spheres of molten rock that permeate primitive meteorites and date to very close to the beginning of the solar system.

For decades, the existence of chondrules has puzzled astrophysicists and cosmochemists as no obvious heat source exists at the time and location of their formation. Herbst and Greenwood set out to find this elusive heat source by combining their expertise in astronomy and earth science, respectively.

Jim Greenwood

James Greenwood

“It could be that the heat source is hot lava — oceans of magma– that may appear on nascent planets in their earliest days. The heat source is radioactive decay of a short-lived isotope of Aluminum, incubated in planetesimals with the size of small asteroids and brought to the surface as molten rock,” Herbst said.

Most of the material available for planet formation ends up on a planet very early on. A few “lucky bits,” represented by the primitive meteorites, avoided collision with a planet until just recently.

“It is, perhaps, not surprising that many, if not all of them, had a close encounter with a hot planetesimal that produced the chondrules and, likely, the chondritic meteorite in which they are embedded,” he said.

NASA Supports Greenwood’s Extraterrestrial Materials Research

James “Jim” Greenwood

Jim Greenwood

Jim Greenwood, assistant professor of earth and environmental sciences, was awarded a Faculty Seed Research Grant from the Connecticut Space Grant Consortium, supported by NASA. The honor comes with a $6,000 award.

Greenwood will use the grant to support his research on “D/H of ‘Dry’ Extraterrestrial Materials.”

Understanding the distribution, delivery, and processing of volatiles in the solar system is of fundamental interest to planetary science. Volatiles influence a number of important properties of planetary bodies, such as the cooling, differentiation, volcanism, tectonism, climate, hydrosphere/atmospheres and especially habitability.

Greenwood will use the award to develop a new state-of-the-art inlet system for the measurement of hydrogen and water and their hydrogen isotope composition in nominally anhydrous extraterrestrial materials. This inlet system will work in conjunction with the Wesleyan Hydrogen Isotope Mass Spectrometer, a Thermo Delta Advantage isotope ratio mass spectrometer installed in August 2014.

With the new system in place by the end of the project period, Greenwood and fellow researchers will be in position to measure hydrogen and water in two Apollo mare basalt rock samples.

“This will increase sensitivity for water by 250x our current measurement,” Greenwood said. “The added capability will allow us to make new and exciting measurements of volatiles in important planetary materials, such as these lunar rock samples.”

Read past News @ Wesleyan stories on Greenwood here.

Singer ’15 to Study Moon Rocks as Connecticut Space Grant Fellow

Jack Singer '15 holds a fragmented lunar sample (Apollo 12039,3), a crucial sample for studying his mineral of interest — apatite — on the moon.

Jack Singer ’15 holds a fragmented lunar sample (Apollo 12039,3), a crucial sample for studying his mineral of interest — apatite — on the moon. This summer, Singer received a Connecticut Space Grant College Consortium grant to fund his summer research in the Earth and Environmental Sciences Department.

As a recent recipient of an undergraduate research fellowship, Jack Singer ’15 is spending his summer at Wesleyan studying the geochemical evolution of the moon. 

The fellowship, supported by the Connecticut Space Grant College Consortium, comes with a $5,000 award. Grantees are expected to work on research related to space/aerospace science or engineering under the guidance of a faculty member or a mentor from industry.

By using a microscope in Wesleyan's Solar Systems Geochemistry Lab, Jack Singer takes a closer look at a Lunar sample.

By using a microscope in Wesleyan’s Solar Systems Geochemistry Lab, Jack Singer takes a closer look at a lunar sample.

For the next three months, Singer will work on various research projects with his advisor James Greenwood, assistant professor of earth and environmental science. Singer will first prepare a fragmented lunar sample (Apollo 12035,76) for analysis under an ion microprobe. An ion microprobe applies a beam of charged ions to the sample and helps determine the composition of the material.

This rock contains olivine, a mineral that is mysteriously sparse in many different lunar samples.

“By analyzing the melt inclusions contained within olivine in this rock, I’ll be able to better understand geochemical evolution of the moon,” Singer said.

Singer’s second project is more experimental. He’s attempting to model and quantify diffusion in a late-stage lunar environment (one of the last regions to cool on the moon) by synthesizing a granite-rich model lunar glass.

Singer will heat this glass past its melting point and place it in contact with solid terrestrial apatite — the Moon’s major water-bearing mineral — and measure how elements diffuse across the glass-grain (or solid-liquid) boundary.

Jack Singer and his advisor, James Greenwood, will travel to Japan this summer to use an ion microprobe at Hokkaido University.

Jack Singer and his advisor, James Greenwood, will travel to Japan this summer to use an ion microprobe at Hokkaido University.

“This type of analysis helps us to better understand the processes that occurred during the last stages of lunar cooling,” he explained.

In addition, Singer and Greenwood will travel to Japan this summer to use an ion microprobe at Hokkaido University.

“This machine allows us to analyze and measure stable isotope ratios in the minerals we are interested in, and can therefore tell us something about the fractionation and geochemical history of the lunar body,” Singer said.

Next fall, Singer will write about his research findings.

NASA Supports Greenwood’s Research on the Moon’s Water

James “Jim” Greenwood

James “Jim” Greenwood

Assistant Professor of Earth and Environmental Sciences James “Jim” Greenwood has received a $331,000 grant from NASA to support his research on the moon’s water.

His proposed research, tracking water in rock samples brought back by the Apollo missions, will “take a giant leap towards solving one of the most important questions in planetary science – whether the Moon is wet or dry,” Greenwood said.

“We’ll be studying pockets of glass trapped in early and late-crystallizing minerals in lunar mare basalt samples,” Greenwood said. “We will measure water and other volatile elements in these trapped melt pockets to reconstruct the volatile history of the samples as they cooled and crystallized near the lunar surface.”

The NASA grant is part of NASA’s Lunar Advanced Science and Exploration Research program.

Greenwood intends to use the grant, which will be distributed over four fiscal years, to fund one Wesleyan undergraduate per summer to conduct research in his lab. The grant will also allow Greenwood to do critical measurement work at Hokkaido University in Sapporo, Japan.

This project is only the latest initiative in Greenwood’s intensive work on lunar rocks, and the Moon’s relative wetness. Most recently he and four colleagues co-authored a paper in the prestigious journal Science, casting doubt on the theory of abundant lunar water, while simultaneously boosting theories around the Moon’s creation, several billion years ago.

 

Greenwood, Colleagues Debunk Sloshy Lunar Theory

James Greenwood, assistant professor of earth and environmental sciences, studies the potential of water on the moon.

James Greenwood, assistant professor of earth and environmental sciences, studies the potential of water on the moon.

James “Jim” Greenwood, assistant professor of earth and environmental sciences, and four colleagues have published a paper that casts doubt on the theory of abundant water on the moon while simultaneously boosting theories around the creation of the moon, several billion years ago.

The paper, “The Lunar Apatite Paradox,” published March 20 in the prestigious journal Science, stems from work involving the mineral apatite, the most abundant phosphate in the solar system. (Along with its presence on planets, it’s found in teeth and bones.)

Initial work on the lunar rocks brought back to Earth by the Apollo missions indicated that the Moon was extremely dry. Any evidence of water was dismissed as contamination from Earth.

But more recent experiments have shown the presence of plenty of water in grains of apatite derived from lunar rocks. Greenwood and colleagues sought to figure out whether, or how that could be.

“We formulated a solution to the problem of how you get this much water into moon apatite by using a mathematical model,” Greenwood said.