CosmoELEMENTS

CosmoELEMENTS keeps us in touch with exciting discoveries in cosmochemistry and provides short articles that can be used in the classroom or report on the space missions carrying geochemical and mineralogical instruments.

Proposals for future articles are welcome and should be sent to the Elements Executive Editor, or to the Column Editor, Cari Corrigan, at corriganc@si.edu

Credit: NASA

Sulfur in the Apollo Lunar Basalts and Implications for Future Sample-Return Missions

By , , and | October, 2020

Between 1969 and 1972, Apollo mission astronauts explored the lunar surface, collecting geologic materials and returning them to Earth for careful study. After consideration of many lines of evidence, one of the many major results of studying the Apollo rocks is the broad scientific consensus that the Moon formed from the debris of a giant impact of a large body with the proto-Earth (e.g., Stevenson 1987). This left the Moon depleted in highly volatile elements such as hydrogen, relative to Earth. So it was thought.

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Primitive Meteorite Contains Cometary Surprise

By | June, 2020
Elements Cover v16n3 Redox Engine of Earth

Comets, and some primitive asteroids, preserve the microscopic remnants of the basic building blocks of rocky bodies in our solar system. Analyzing these building blocks can provide important clues both to the source of the water for Earths’ oceans and to the inventory of organic matter delivered to the early Earth. In general, samples from comets preserve a greater abundance of organic matter and primordial presolar dust grains from the protosolar molecular cloud, and generations of stars older than the sun, than do samples from asteroids. Meteorites, which come from asteroids, generally have less organic matter and preserve fewer presolar grains. This is because asteroids and comets formed at different places in the solar nebula, and, thus sampled different distributions of organic and mineral components. Furthermore, the warmer conditions on asteroids allowed for liquid water and greater subsequent physical and chemical alteration of the accreted material.

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Metbase.org as a Research and Learning Tool for Cosmochemistry

By | February, 2020

The digital age has transformed the ways by which we live and work. Surprisingly, it is still challenging to agree on a general definition of what digital really means. There is a telltale picture taken by film director Stanley Kubrick in 1946 of people in the New York City (USA) subway. In this picture, almost all the commuters are looking down and into their newspapers. If you now replace the newspapers with smartphones, then the scene might have been shot on a subway today. But there is at least one crucial difference between the two pictures: information density. A newspaper holds only a few tens of kilobytes (kB) of information, whereas a smartphone can hold up to a terabyte (TB). This is six to eight orders of magnitude more than a newspaper. Furthermore, almost all the exabytes (260) of information by humankind has become accessible to us via the internet and through our smartphones. In combination with apps, this vast amount of information is structured and tailored to all our various daily needs. This is the power and attractiveness of digital: the vastness of the information has been condensed, structured, and made accessible through digital devices such as smartphones. Hence, if we use computers solely for calculations – their initial purpose – this is not what we mean by digital.

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Exploring the Moon in the 21st Century

By and | October, 2019

In 2019, we are celebrating the 50th anniversary of NASA’s momentous Apollo expeditions to the Moon. The samples brought back by the astronauts, and the fieldwork those astronauts performed on the lunar surface, cemented the Moon’s status as the cornerstone of the solar system. It is not an exaggeration to say that the Apollo expeditions transformed our understanding of our solar system, and, in fact, most of the discoveries made in planetary science since the 1960s can trace directly, or indirectly, from the scientific results of those Apollo expeditions.

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The Apollo Sample Collection: 50 Years Of Solar System Insight

By | July, 2019

The Apollo program was the seminal moment in modern human history and the crowning technological achievement of the 20th century. In addition to the obvious historical, cultural, and technological significance of the Apollo program, scientific results from the Apollo lunar samples have had a lasting impact on a range of scientific fields, none more so than on the fields of planetary science and cosmochemistry. Over the past five decades, studies of these lunar samples have yielded significant insights into planetary bodies throughout the solar system. Despite the Apollo samples being a static collection, recent and ongoing studies continue to make new significant discoveries. Here, we will discuss the collection, curation, and study of the Apollo lunar samples and look forward to some expected new developments in the coming years.

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Impact Earth: A New Resource for Outreach, Teaching, and Research

By and | February, 2019

When one mentions the word “geology”, most people will likely think of volcanoes, glaciers, or majestic mountain ranges. Beginning in the late 18th century with the work of pioneering Scottish geologist James Hutton (1726–1797), uniformitarianism emerged as a central tenet of geology and remained so well into the 20th century. Central to the idea of uniformitarianism is the concept of gradualism, whereby processes throughout time occur at the same or similar rates, leading to the famous concept that “The present is the key to the past.”

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Hopewell Meteoritic Metal Beads: Clues to Trade 2,000 Years Ago

By | October, 2018

Naturally occurring iron metal is exceedingly rare on the surface of the Earth. Thus, it is little wonder that civilizations dating back thousands of years used iron meteorites—naturally occurring alloys of Fe, Ni, Co and a variety of trace elements—to manufacture knives, fishhooks, adzes, and amulets, among other objects. Perhaps the best known of these is the meteoritic metal blade of a dagger found with the mummified body of King Tutankhamun (Egypt’s 18th dynasty boy pharaoh who ruled ~1332–1323 BC). Unfortunately, the rarity of these materials typically makes it impossible to apply destructive techniques that might allow researchers to not only confirm a meteorite origin, but also identify the meteorite used during manufacturing. Fortunately, the inhabitants of what is today the central United States produced meteorite artifacts in abundance, allowing for the kind of analyses that provides clues to 2,000-year-old trade routes.

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The Enduring Mystery of Australasian Tektites

By | June, 2018

Molten glass rained down from the sky over parts of Southeast Asia, Australia, Antarctica, and into the neighbouring ocean basins during the Pleistocene, about 790,000 years ago. These glass occurrences, long recognized to be remnants of melt formed during meteorite impact, are known as the Australasian tektites. Their distribution defines the largest of at least four known strewn fields across the globe, strewn fields being regions over which tektite glass are scattered from what are thought to be single-impact events. The three other big tektite strewn fields are associated with known source craters, including the Bosumtwi (1.07 Ma, Ghana), Ries (15 Ma, Germany), and Chesapeake Bay (35.5 Ma, USA) impact structures. At only 790,000 years old, the Australasian tektite strewn field is both the youngest and the largest known. Despite much effort, the source crater has yet to be discovered. The search to locate it represents something akin to a “holy grail” in impact cratering studies.

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Asteroid 16 Psyche: NASA’s 14th Discovery Mission

By | February, 2018

When our Solar System was just an infant, thousands of small early planets formed in just a few million years (Scherstén et al. 2006). Some grew to hundreds of kilometers in diameter as they swept up pebbles, dust, and gas within the swirling solar nebula. Heat from the decay of short-lived radioactive isotope 26Al was trapped and, in some cases, melted the planetesimal interiors. The molten interiors quickly differentiated: denser material settled to their centers, leaving lighter silicates to cool into thick mantles that surrounded metal cores (e.g. Weiss and Elkins-Tanton 2013).

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Search (and Discovery) of New Impact Craters on Earth

By | October, 2017

When looking at other terrestrial planetary bodies of the Solar System, such as our Moon, Mars, Mercury or the asteroids, it is obvious that impact craters are the dominant geological features to be seen on their surfaces. On Earth, however, impact craters are not so obvious and, in most cases, they are hard to spot. Our planet is geologically active. Its surface is constantly altered by plate tectonics and erosion and is largely covered by oceans and (densely) vegetated areas, making the identification of impact craters difficult. In addition, on Earth, an impact crater cannot be recognized, like on other planetary bodies, based only on its morphological characteristics because circular features can be formed by a variety of completely different geological processes (e.g. volcanism, salt diapirism, etc.)

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Archived CosmoElements (PDF)

2017201620152014201320122011

2017 Issues -- Volume 13

February 2017

Nicole G. Lunning and Catherine M. Corrigan

"Carbonaceous Chondrite Impact Melts"

 

2016 Issues -- Volume 12

February 2016

Rhiannon Mayne

"Qarabawi's Charm: Looking Beyond the Science"

June 2016

Michael Zolensky

"NASA's Cosmic Dust Program: Collecting Dust Since 1981"

October 2016

Patricia M. Doyle and Alexander N. Krot

"Aqueous Alteration and Accretion of Chondrite Parent Bodies: When and Where"

 

2015 Issues -- Volume 11

February 2015

James W. Ashley

"THE STUDY OF EXOGENIC ROCKS ON MARS—AN EVOLVING SUBDISCIPLINE IN METEORITICS?"

June 2015

Philip A. Bland, Gretchen K. Benedix, and the Desert Fireball Network (DFN) Team

"CATCHING A FALLING STAR (OR METEORITE) – FIREBALL CAMERA NETWORKS IN THE 21st CENTURY"

October 2015

Kelsi Singer

"MEET PLUTO AND CHARON … AND NIX AND HYDRA!"

 

2014 Issues -- Volume 10

February 2014

Larry R. Nittler

"NEAR-SHOEMAKER AT EROS: THE FIRST DETAILED EXPLORATION OF AN ASTEROID"

June 2014

Carl Agee

"BLACK BEAUTY: A UNIQUE 4.4 GA, WATER-RICH METEORITE FROM MARS"

October 2014

Gregory F. Herzog and Rainer Wieler

"COSMOGENIC NUCLIDES IN THE INNER SOLAR SYSTEM: SURFACE EXPOSURE AGES FOR MARS AND ASTEROID 25143 ITOKAWA "

 

2013 Issues -- Volume 9

April 2013

Shoshana Z. Weider and Larry R. Nittler

"THE SURFACE COMPOSITION OF MERCURY AS SEEN FROM MESSENGER"

June 2013

Linda Martel and Cari Corrigan

"THE CHELYABINSK, RUSSIA,
METEORITE FALL"

October 2013

Monica M. Grady

"NITROGEN IN PLANETARY MATERIALS"

 

2012 Issues -- Volume 8

February 2012

Cari Corrigan, Andrew Beck, and Tim McCoy

"MISSIONS TO ASTEROIDS: JOURNEYING TO THE BEGINNING OF OUR SOLAR SYSTEM"

June 2012

Steven B. Simon

"THE ENDURING LEGACY OF THE ALLENDE METEORITE"

October 2012

Donald E. Brownlee

"THE STARDUST COMET MISSION: STUDYING SEDIMENTS FROM THE SOLAR SYSTEM’S FROZEN ATTIC"

 

2011 Issues -- Volume 7

December 2009

Cari Corrigan

"ANTARCTICA: THE BEST PLACE ON EARTH TO COLLECT METEORITES"