The UCLA Dept. of Earth and Space Sciences and the Institute for Planets and Exoplanets are proud to announce the first annual Earth and Space Sciences lecture series to be held during the Exploring Your Universe event on Sunday, November 17th, 2013. Each fun-filled talk will be a half hour long, and will be given in Geology 3656 by scientists at the forefront of the Earth, planetary and space science fields. We recommend you arrive ten minutes early to make sure you get a seat.
EYU 2013 Lecture Schedule in Earth, Planetary, and Space Sciences (3656 Geology)
Long ago, scientists discovered that when a compass points north on Earth, it is not actually pointing to the North Pole. The axis of Earth’s magnetic field is tilted away from the axis that the planet spins about. Every planet in our solar system with a magnetic field follows this rule, except one: Saturn.
When fourth-year graduate student Hao Cao came to UCLA, his advisor, Professor Chris Russell, presented him the opportunity to study data from NASA’s Cassini mission. Arriving at Saturn in 2004, Cassini has been orbiting the planet ever since, measuring Saturn’s magnetic field, among many other things. Cao wondered, “What does the magnetic field tell us about Saturn?”
To answer that question, Cao needed to determine how Saturn’s magnetic field is generated. The sixth planet from the Sun, Saturn is a gas giant composed primarily of hydrogen, the simplest and most abundant of elements in the universe. Inside Saturn, where pressure is a million times greater than at Earth’s surface, hydrogen is thought to exist as liquid metal. The turbulent motions of this electrically conductive hydrogen are what give rise to the magnetic field of Saturn. But metallic hydrogen is also responsible for producing the tilted magnetic field on Jupiter. Cao knew he had to look deeper.
He began contemplating the rocky core that may exist deep in the heart of Saturn, which could shape the metallic hydrogen layer that lies above it. “Zonal winds that move across the planet could reach deep inside the planet and influence the shape of the magnetic field being generated by the metallic hydrogen layer,” said Cao. As a result of these interactions, Cao has produced the best size estimate of Saturn’s core to date. Twice the size and ten times the mass of Earth, but only 1/5th the size of Saturn, this core is the first to be assessed using magnetic field data.
Recently, Cao has begun trying to explain Mercury’s puzzling asymmetric magnetic field using information from NASA’s MESSENGER spacecraft. “When you study a place like Saturn or Mercury, there are many things you learn for the first time,” said Cao. Beyond magnetic field research, Cao is interested in many aspects of planetary science. “Dynamo studies are only part of understanding planets. Formation, internal structure, and dynamics are all related – it’s not an isolated problem,” he said.
Watch a video profile of Hao Cao here. Learn more about his research here.
Using images captured by NASA’s STEREO spacecraft, UCLA Prof. David Jewitt and researcher Jing Li have detected a comet-like tail around the asteroid Phaethon. The iconic plumes of comets are normally created when cometary ice sublimates in the heat of the Sun, creating a dusty tail. However, Phaethon’s orbit takes it so close to the Sun that all the ice should have been completely scorched away long ago. Instead, Phaethon’s dust tail may have originated from dry, disintegrated rock on the surface of the asteroid pushed into space by solar radiation. Learn more about this recent discovery here.
UCLA Professor David Paige will join Bill Nye (the Science Guy) to provide live commentary during the LADEE mission launch on Friday, September 6th, at 7:30pm PST. The event, sponsored by the Planetary Society, will be broadcast live on KPCC. The LADEE (Lunar Atmosphere and Dust Environment Explorer) mission will orbit the Moon for approximately 100 days to collect information about its atmosphere and the lunar dust environment. Tune in to learn more about this exciting mission!
Professor David Jewitt weighs in on the recent discovery of an asteroid-like object traveling in the same planetary orbit as Uranus. Read more about the discovery, published in the journal Science, in this LA Times article.
A topographic false-color map of Mars including some of the largest volcanoes and the largest canyon in the solar system. Image Credit: NASA/JPL/Caltech/Arizona
Few people can claim that their children learned to walk in the forests of Yosemite National Park. Professor An Yin, who has spent much of his 26 years at UCLA conducting fieldwork in Tibet, the Himalayas, and California, can. Having spent his graduate career investigating remote areas of Glacier National Park, Yin’s mountaineering experience equipped him for the challenging Asian fieldwork and tectonic research that earned him the Donath Medal from the Geological Society of America. “It was a frontier in an area that was not explored before, despite it being on Earth,” said Yin. “Knowing almost nothing about this large area, I tried to make a synthesis.” Nowadays, Yin spends less time in Tibet and the Himalayas, making only two trips a year, usually to drop off graduate students to conduct their own fieldwork. Instead, he has directed his interest toward the fledgling field of research known as planetary geology.
In 2008, Yin began applying his Earth geology expertise to landscapes he observed on other planets. “Having limited data to create a tectonic story in large areas of Asia gave me the know-how to explore planet-related problems,” Yin said. “The process turns out to be quite similar.” In his early days of Tibetan research Yin used satellite images to estimate locations of faults before going into the field; similarly, he uses satellite images to understand planetary geology from afar. Images today, however, provide more clues about the geology. “High-resolution images have revolutionized mapping and geologic interpretation,” said Yin. “We still can’t determine composition, but we can say for certain how much and in what manner a feature is offset from its original position.”
To explain the features he observes on Mars, Yin has developed a theory that invokes a one-plate tectonic system. Unlike Earth, which has 15 major tectonic plates that move continuously and are responsible for forming mountains and oceans, Mars has only one plate that moves very slowly. Moving at a pace 1000 times slower than those on Earth, Mars’ tectonic plate produces plate-boundary features like volcanoes and faults that materialize in a relatively small area and grow very large. Maps of Mars show that almost all its prominent features are confined to just one-third of the planet. Among these features are the colossal Tharsis Montes, three volcanoes so large they could fit 32 of Earth’s three-mile-high Andean volcanoes into the volume they occupy.
Although Mars’ features are grander, they share many characteristics with Earth’s terrain. This observation led Yin to contemplate the underlying processes that create the two planets’ surfaces. For not only Mars, but for many planetary bodies, the differences in these processes may be the result of their individual “evolutionary paths,” said Yin.
Piecing together the story of how a planet’s geology has changed over time requires Yin to use all the resources at his disposal. “The problem with planetary geology is that you see a static image,” he said, “the history is harder to show.” One way of revealing the history is by observing it. In Yin’s laboratory, he and his graduate students design sandbox experiments to reveal how faults, mountains, and valleys develop. While these experiments are intended to mimic natural conditions, they do not represent the exact history of any process, and act more as a guide to help determine whether their basic assumptions are correct.
From these experiments, Yin has determined that the histories of Mars and Earth are quite similar, differing only in their rates of evolution. “Mars is smaller and has less heat, so the driving engine is not as powerful as Earth’s,” said Yin. Although Mars and Earth appear to be quite similar, other planetary bodies may have very dissimilar evolutionary paths.
Yin’s newest foray into planetary science involves Enceladus, an icy moon of Saturn. He interprets the famous “Tiger Stripes” that periodically eject water vapor from its south pole as a product of the movement of the moon’s icy shell, and prefers to call them “Horsetails,” after a Himalayan feature they so closely mimic. While Yin can decipher portions of Enceladus’ history from its surface features, it remains unclear whether there is a global or localized ocean beneath the icy surface. “This is an actively debated subject,” said Yin, “but for now I can only tell the story of what happened.”
From the otherworldly geology he’s studied thus far, Yin has learned that “the planetary world is something that defies common sense in many respects. We have an idea of how a planet should develop and what it should look like, and we find exception after exception after exception.” Yin hopes that his continued interdisciplinary approach to planetary geology will result in observing “overlapping parts of commonality” between planets that could reveal more about planetary evolution as a whole.
Watch a video profile of An Yin here. Learn more about his research here.
This year’s Exploring Your Universe (EYU) event at UCLA will be held on Sunday, November 17th, 2013. Explore Your Universe is an annual event held on the UCLA campus that includes science exhibitions, hands-on activities, demonstrations and experiments. The event is free to the public and promises an exciting time and a great learning experience for kids and adults alike.
To read more about previous years’ EYU events and other iPLEX outreach events, please visit our outreach page and stay tuned for more updates!
The THEMIS spacecraft in orbit around the Earth. Image Credit: SVS/NASA
The Sun is a veritable force in our solar system. It emits a tremendous amount of heat and energy, called the solar wind, which constantly blows and buffets the planets at a velocity almost two thousand times faster than the average jet plane. Akin to an invisible shield, the Earth’s magnetic field deflects most of the solar wind, but it happens often that the magnetic fields of the Earth and Sun briefly and directly come into contact with one another.
When the fields connect, part of Earth’s magnetic field “peels away from the sunward side and drapes around the back of the planet,” said sixth-year graduate student, Christine Gabrielse. The backside of Earth’s magnetic field, or magnetotail, is “squeezed from the outside as a result of the peel back,” she said. Eventually, two points on the interior of the Earth’s magnetic field meet in what is called a near-Earth reconnection, releasing a great deal of energy that flows toward Earth. “These powerful phenomena, known as substorms, can create more than picturesque auroras”, Gabrielse said. “They can damage spacecraft or astronauts, or even ground-based systems.” On March 13th, 1989, one such storm caused a legendary power outage in Canada’s Quebec province that left more than three quarters of a million people without power for nearly twelve hours.
While scientists had studied substorms for years, many questions remained regarding these space weather events. Proposed by UCLA Professor Vassilis Angelopoulos, NASA’s Time History of Events and Macroscale Interactions During Substorms (THEMIS) mission was designed to answer some of these questions.
Launched in February 2007, the mission consisted of five identical satellites deployed to critical locations around Earth. Unprecedented at the time, THEMIS allowed scientists to track the flow of energy around Earth and determine how and where substorms initiate. “The spacecraft gave us five pinholes in the magnetic curtain we are trying to see through,” said Drew Turner, an assistant researcher at UCLA working on the THEMIS mission.
From their unique orbits, engineered to simultaneously provide five key perspectives of the vast space environment, the spacecraft quickly solved the questions they’d set out to answer. “In 2008, THEMIS repeatedly showed that reconnection happens in the magnetotail first, activating a substorm,” said Gabrielse. With its primary goal accomplished, THEMIS set new objectives. Splitting the satellites into two groups, three continued to orbit Earth, while two were sent to the Moon as a ‘new’ mission called Acceleration, Reconnection, Turbulence and Electrodynamics of the Moon’s Interaction with the Sun (ARTEMIS). “The extension to ARTEMIS was quite miraculous,” said Turner. “The spacecraft were not equipped with the ability to maneuver out of their orbit. The THEMIS engineers and operators sent satellites to the Moon by way of tiny puffs of rocket fuel.”
Using “the most comprehensive plasma instruments we’ve sent to the Moon,” the two ARTEMIS satellites are now busy determining the rock types on its surface, said Turner. The satellites detect small variations in the Moon’s particle and electric fields allowing them to distinguish between different materials. “It’s a natural way of detecting surface composition from afar,” said Turner. In addition, the satellites are improving substorm research by studying the Earth’s space environment from their entirely new viewpoint near the Moon. “With the two spacecraft at the Moon we can test what’s happening on the other side of the reconnection,” said Shanshan Li, a fifth-year UCLA graduate student. “We can start to form a three-dimensional substorm model of Earth’s space environment.”
The THEMIS satellites that have remained in orbit around Earth are “scientific goldmines,” according to Turner. Coordinating observations with the Van Allen Probes, a pair of recently launched NASA satellites, they were able to detect a previously unknown layer of charged particles surrounding Earth. Turner said, “in a huge and complex system, my bread and butter is combining as many satellites’ data as I can to get as complete a global picture as possible.”
With the Sun approaching a period of increased activity, the media have begun to report space weather more often. “It’s good to see that society is taking an interest,” said Turner. “We’ve become increasingly dependent on space-based assets,” said Turner. “Even something as simple as using an ATM will most often result in a satellite-relayed signal at some point.” Since large space storms can have huge societal impacts, it is important to be able to see them coming. “Just like meteorologists want to be able to forecast a storm on Earth, we want to be able to predict a storm in space,” said Gabrielse. “Ultimately, our aim is to determine what’s going on in the Sun-Earth environment and try to better understand it.”
The LA Times and Science Daily report on UCLA Department of Earth, Planetary and Space Science Associate Professor Axel Schmitt’s recent research to determine the age of Mars’ meteorites. Read the full-length articles here:
Titan in front of Saturn and its rings. Image Credit: NASA/JPL/Caltech/SSI
Saturn’s largest moon, Titan, is an icy world dominated by extensive sand dunes at the equator, methane-filled lakes near the poles, and vast networks of dry riverbeds in between. Wrapped in a nitrogen atmosphere thicker than Earth’s, Titan is an ideal test bed for studying planetary climate models for UCLA Assistant Professor Jonathan Mitchell.
“Titan is probably the most Earth-like place in the solar system in terms of its very active weather cycle,” said Mitchell. But a weather forecaster on chilly Titan would be more likely to predict a liquid methane downpour than the water-based showers we are accustomed to on Earth. “Titan is too cold for water to play a role in the weather. Instead, it rains and hails methane, the natural gas we use as fuel for our stoves,” Mitchell said.
So is Titan a veritable tinder box, an enormous gas leak ready to catch fire at the slightest spark? Not at all, said Mitchell. “You might worry about it exploding, but all the oxygen is locked up into water. If you wanted a lighter that you could carry around on Titan, then you’d carry around a flint with a little vial of oxygen because there is plenty of methane in the air and the limiting ingredient is the oxygen for combustion.”
Titan has surface temperatures nearly 300 degrees Fahrenheit below zero (-180° Celsius). Water makes up about half the solid body by mass, and where you would expect to find a rocky crust on a terrestrial planet like Earth, Titan’s surface layers are composed mainly of ice. “Water is essentially Titan’s rock,” said Mitchell. “These temperatures are so far beyond the realm of human experience that they’re hard to even grasp.”
Despite the frigid conditions, Titan’s climate patterns are technically quite tropical, Mitchell said. “On Earth, we have a certain temperature difference between the equator and the poles which gives rise to vastly different climates on the surface, like tropical islands versus Antarctica,” he said. “On Titan, this temperature difference is essentially erased, which makes its climate all tropics.” The subzero weather results from the fact that Titan spins more slowly than Earth, taking sixteen days to complete a full rotation, and also because of its smaller size. While Titan is larger than Mercury and is the second largest moon in the solar system, it is still less than half the size of Earth.
To be able to understand and predict weather patterns on Titan, Mitchell and his colleagues rely on observations from NASA’s Cassini spacecraft that help them improve their computer simulations. “We’re looking at the visible and near-infrared images of Titan to survey cloud features and find interesting spatial patterns from the evolution of storms,” Mitchell said. Because Cassini can only take measurements at Titan during its regular flyby once every few weeks, an accurate computer model is critical to understanding weather patterns on the icy body.
Mitchell’s research may help explain a curious phenomenon called super-rotation, which causes Titan’s atmosphere to circle the planet at speeds higher than expected. “Super-rotation means that the atmosphere as a whole is spinning faster than the planetary surface,” Mitchell said. “This is puzzling because we typically think an atmosphere gains its momentum from friction with the surface.”
Since coming to UCLA in 2009, Mitchell has expanded his work to include Earth’s ancient climate, which he hopes will help him to better predict how regional climates will change as the planet warms over the next century. “We’ve essentially nailed the problem of anthropogenic greenhouse gases warming the planet,” Mitchell said. “The much harder question is: what will be the resulting impacts?”
Mitchell grew up in rural Iowa where incessant gazing at the stars as a small child led to the occasional tripping injury. “I’ve always been curious, and that’s what made me a scientist,” Mitchell said. “I was destined to be looking up.” As a graduate student at the University of Chicago, Mitchell originally studied cosmology and gravitational lensing. But after a few years, he switched fields to study the physics of climate on Earth and other planets. “Cassini was arriving at Saturn about that time so I decided to take a pit stop at Titan, and I haven’t really left since,” he said.
Mitchell, who enjoys singing in small group ensembles in his spare time, has found a home at UCLA. “Academically, I just can’t imagine a better fit for me. I have very broad interests and UCLA is a place where you can really expand and learn.”
Watch a video profile of Jonathan Mitchell here. Learn more about his research here.
Using images captured by NASA’s STEREO spacecraft, UCLA Prof. David Jewitt and researcher Jing Li have detected a comet-like tail around the asteroid Phaethon. The iconic plumes of comets are normally created when cometary ice sublimates in the heat of the Sun, creating a dusty tail. However, Phaethon’s orbit takes it so close to the Sun that all the ice should have been completely scorched away long ago. Instead, Phaethon’s dust tail may have originated from dry, disintegrated rock on the surface of the asteroid pushed into space by solar radiation. Learn more about this recent discovery 
UCLA Professor David Paige will join Bill Nye (the Science Guy) to provide 
Professor David Jewitt weighs in on the recent discovery of an asteroid-like object traveling in the same planetary orbit as Uranus. Read more about the discovery, published in the journal Science, in this 
