The Sutter's Mill meteorite is a

carbonaceous chondrite Carbonaceous chondrites or C chondrites are a class of chondritic meteorites comprising at least 8 known groups and many ungrouped meteorites. They include some of the most primitive known meteorites. The C chondrites represent only a small prop ...

which entered the Earth's

atmosphere An atmosphere () is a layer of gas or layers of gases that envelop a planet, and is held in place by the gravity of the planetary body. A planet retains an atmosphere when the gravity is great and the temperature of the atmosphere is low. A s ...

and broke up at about 07:51

Pacific Time The Pacific Time Zone (PT) is a time zone encompassing parts of western Canada, the western United States, and western Mexico. Places in this zone observe standard time by subtracting eight hours from Coordinated Universal Time ( UTC−08:00). ...

on April 22, 2012, with fragments landing in the United States. The name comes from

Sutter's Mill Sutter's Mill was a water-powered sawmill on the bank of the South Fork American River in the foothills of the Sierra Nevada in California. It was named after its owner John Sutter. A worker constructing the mill, James W. Marshall, found gold t ...

, a

California Gold Rush The California Gold Rush (1848–1855) was a gold rush that began on January 24, 1848, when gold was found by James W. Marshall at Sutter's Mill in Coloma, California. The news of gold brought approximately 300,000 people to California fro ...

site, near which some pieces were recovered. Meteor astronomer

Peter Jenniskens Petrus Matheus Marie (Peter) Jenniskens (born 2 August 1962, in Horst) is a Dutch-American astronomer and a senior research scientist at the Carl Sagan Center of the SETI Institute and at NASA Ames Research Center. He is an expert on meteor showe ...

assigned Sutter's Mill (SM) numbers to each

meteorite A meteorite is a solid piece of debris from an object, such as a comet, asteroid, or meteoroid, that originates in outer space and survives its passage through the atmosphere to reach the surface of a planet or Natural satellite, moon. When the ...

, with the documented find location preserving information about where a given meteorite was located in the impacting meteoroid. As of May 2014, 79 fragments had been publicly documented with a find location. The largest (SM53) weighs , and the second largest (SM50) weighs . The meteorite was found to contain some of the oldest material in the

Solar System The Solar SystemCapitalization of the name varies. The International Astronomical Union, the authoritative body regarding astronomical nomenclature, specifies capitalizing the names of all individual astronomical objects but uses mixed "Solar S ...

. Two 10-micron diamond grains (

xenolith A xenolith ("foreign rock") is a rock fragment (country rock) that becomes enveloped in a larger rock during the latter's development and solidification. In geology, the term ''xenolith'' is almost exclusively used to describe inclusions in igne ...

s) were found in meteorite fragments recovered before any rain fell as the rain would degrade the purity of the meteorites for scientific study. In primitive meteorites like Sutter's Mill, some grains survived from what existed in the cloud of gas, dust and ice that formed the Solar System.

History

During the 2012

Lyrids The April Lyrids are a meteor shower lasting from April 16 to April 25 each year. The radiant of the meteor shower is located in the constellation Lyra, near its brightest star, Vega. The peak of the shower is typically around April 22 each year. ...

meteor shower, a

bolide A bolide is normally taken to mean an exceptionally bright meteor, but the term is subject to more than one definition, according to context. It may refer to any large crater-forming body, or to one that explodes in the atmosphere. It can be a ...

and

sonic boom A sonic boom is a sound associated with shock waves created when an object travels through the air faster than the speed of sound. Sonic booms generate enormous amounts of sound energy, sounding similar to an explosion or a thunderclap to t ...

rattled buildings in

California California is a U.S. state, state in the Western United States, located along the West Coast of the United States, Pacific Coast. With nearly 39.2million residents across a total area of approximately , it is the List of states and territori ...

and

Nevada Nevada ( ; ) is a U.S. state, state in the Western United States, Western region of the United States. It is bordered by Oregon to the northwest, Idaho to the northeast, California to the west, Arizona to the southeast, and Utah to the east. N ...

in daylight conditions in the early morning at 07:51 PDT on 22 April 2012. The

meteor air burst A meteor air burst is a type of air burst in which a meteor explodes after entering a planetary body's atmosphere. This fate leads them to be called fireballs or bolides, with the brightest air bursts known as superbolides. Such meteoroids were ...

was caused by a random

meteoroid A meteoroid () is a small rocky or metallic body in outer space. Meteoroids are defined as objects significantly smaller than asteroids, ranging in size from grains to objects up to a meter wide. Objects smaller than this are classified as micr ...

, not a member of the Lyrids shower. The bolide was so bright that witnesses were seeing spots afterward. The falling meteorites were detected by

weather radar Weather radar, also called weather surveillance radar (WSR) and Doppler weather radar, is a type of radar used to locate precipitation, calculate its motion, and estimate its type (rain, snow, hail etc.). Modern weather radars are mostly puls ...

over an area centered on the Sutter's Mill site in Coloma, between

Auburn, California Auburn is a city in and the county seat of Placer County, California, United States. Its population was 13,776 during the 2020 census. Auburn is known for its California Gold Rush history and is registered as a California Historical Landmark. Au ...

, and

Placerville, California Placerville (, ; formerly Old Dry Diggings, Dry Diggings, and Hangtown) is a city in and the county seat of El Dorado County, California. The population was 10,747 as of the 2020 census, up from 10,389 as of the 2010 census. It is part of the Sa ...

. Robert Ward found a small CM chondrite fragment in the Henningsen Lotus Park just west of Coloma, CA on 24 April 2012. Later that day,

found a crushed 4 g meteorite in the parking lot of that same park and Brien Cook found a 5 g meteorite off Petersen Road in Lotus. These were the only meteorites found before rain hit the area on 25 April. On 1 May 2012, the James W.

Marshall Gold Discovery State Historic Park Marshall Gold Discovery State Historic Park is a state park of California, United States, marking the discovery of gold by James W. Marshall at Sutter's Mill in 1848, sparking the California Gold Rush. The park grounds include much of the histo ...

's ranger Suzie Matin discovered two pieces of the meteorite (SM14 @ 11.5 grams) in her front yard. The park contains what is now known as Sutter's Mill (site). On 3 May 2012 scientists with the

Ames Research Center The Ames Research Center (ARC), also known as NASA Ames, is a major NASA research center at Moffett Federal Airfield in California's Silicon Valley. It was founded in 1939 as the second National Advisory Committee for Aeronautics (NACA) laborat ...

and the

SETI Institute The SETI Institute is a not-for-profit research organization incorporated in 1984 whose mission is to explore, understand, and explain the origin and nature of life in the universe, and to use this knowledge to inspire and guide present and futu ...

utilized an

airship An airship or dirigible balloon is a type of aerostat or lighter-than-air aircraft that can navigate through the air under its own power. Aerostats gain their lift from a lifting gas that is less dense than the surrounding air. In early ...

to search the

strewn field The term strewn field indicates the area where meteorites from a single fall are dispersed. It is also often used for the area containing tektites produced by large meteorite impact.''Tektites in the geological record: showers of glass from the sky ...

for the impact scars of kg-sized meteorites, but it is now understood that the high entry speed prevented the survival of meteorites as large as found in the

Murchison meteorite The Murchison meteorite is a meteorite that fell in Australia in 1969 near Murchison, Victoria. It belongs to the carbonaceous chondrite class, a group of meteorites rich in organic compounds. Due to its mass (over ) and the fact that it was an ...

fall. Ground-based searches resulted in the additional recovery of two pristinely collected meteorites (SM12 and SM67) for scientific study.

Comparisons

This is the third witnessed

meteorite fall A meteorite fall, also called an observed fall, is a meteorite collected after its fall from outer space was observed by people or automated devices. Any other meteorite is called a "find". There are more than 1,100 documented falls listed in w ...

in California, following Red Canyon Lake on 11 August 2007 and San Juan Capistrano on 15 March 1973, while a few months after this event the

Novato meteorite The Novato meteorite is an ordinary chondrite which entered the Earth's atmosphere and broke up over Northern California at 19:44 Pacific Time on 17 October 2012. The falling bolide created a bright fireball and sonic booms and fragmented into sm ...

fell on 17 October 2012. A consortium of over 50 scientists investigated the circumstances of the impact and the properties of the meteorites. The event was recorded by two

infrasound Infrasound, sometimes referred to as low status sound, describes sound waves with a frequency below the lower limit of human audibility (generally 20 Hz). Hearing becomes gradually less sensitive as frequency decreases, so for humans to perce ...

monitoring stations of the

Comprehensive Nuclear-Test-Ban Treaty Organization The Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO) is an international organization that will be established upon the entry into force of the Comprehensive Nuclear-Test-Ban Treaty, a Convention that outlaws nuclear test explosions. It ...

’s International Monitoring System. The preliminary analyses are indicative of an energy yield of approximately four kilotons of TNT equivalent. Hiroshima's "

Little Boy "Little Boy" was the type of atomic bomb dropped on the Japanese city of Hiroshima on 6 August 1945 during World War II, making it the first nuclear weapon used in warfare. The bomb was dropped by the Boeing B-29 Superfortress ''Enola Gay'' p ...

" had a yield of about 16 kt. The air burst had approximate coordinates of . Based on the infrasound signal and the brightness of the fireball in photographs and two video records, the incoming meteoroid was estimated to have been in diameter, between the size of a dish washer and a

mini van The Mini is a small, two-door, four-seat car, developed as ADO15, and produced by the British Motor Corporation (BMC) and its successors, from 1959 through 2000. Minus a brief hiatus, original Minis were built for four decades and sold during ...

. Before entry in Earth's atmosphere, the meteoroid probably had an

absolute magnitude Absolute magnitude () is a measure of the luminosity of a celestial object on an inverse Logarithmic scale, logarithmic Magnitude (astronomy), astronomical magnitude scale. An object's absolute magnitude is defined to be equal to the apparent mag ...

(H) of roughly 31. The meteoroid entered at a record speed of , the fastest fireball on record from which meteorites were later recovered. It broke apart at an altitude of , the highest breakup event on record resulting in meteorites on the ground. Before entry, the meteoroid moved on an eccentric orbit, stretching from just inside the orbit of Jupiter to the orbit of Mercury. The orbit had a shallow inclination and an orbital period suggesting that this meteoroid originated in the 3:1 mean motion resonance with Jupiter. The CM chondrite

Maribo Maribo is a town in Lolland Municipality in Region Sjælland on the island of Lolland in south Denmark. It was the municipal seat of the former Maribo Municipality, until 1 January 2007, and then it became the seat of the current Lolland Muni ...

moved on a similar orbit, but rotated by 120 degrees in the direction of the line of apsides. The asteroid family that is the source region of CM chondrite-type meteorites is now thought to be located close to the 3:1 mean motion resonance, in low-inclined orbits, and may be the Eulalia asteroid family. The meteorite type is similar to that of the 1969

in Australia. Unlike Murchison, Sutter's Mill shows clear brecciation: fragments of CM lithologies with different aqueous alteration and thermal processing histories are embedded in a fine grained CM matrix material. The Sutter's Mill meteorite originated from near the surface of its parent body. As a whole, Sutter's Mill is harder than Murchison. The pre-rain collected meteorite SM2 was found to contain the mineral

oldhamite Oldhamite is a calcium magnesium sulfide mineral with the chemical formula . Ferrous iron may also be present in the mineral resulting in the chemical formula . It is a pale to dark brown accessory mineral in meteorites. It crystallizes in the cub ...

(CaS), a mineral that reacts readily with water vapor. This

ic material may have come from

enstatite Enstatite is a mineral; the magnesium endmember of the pyroxene silicate mineral series enstatite (MgSiO3) – ferrosilite (FeSiO3). The magnesium rich members of the solid solution series are common rock-forming minerals found in igneous and m ...

chondrites impacting on the surface of the CM chondrite parent body in the past. The Sutter's Mill meteorite is used to test sample collection and analysis procedures for NASA's

OSIRIS-REx OSIRIS-REx (Origins, Spectral Interpretation, Resource Identification, Security, Regolith Explorer) is a NASA asteroid-study and sample-return mission. The mission's primary goal is to obtain a sample of at least from 101955 Bennu, a carbonac ...

sample return mission.

Examples

File:Sm39-Miller-2 5g.JPG, SM39 (2.5 g) File:SM-Miller-5.9g.jpg, Mike Miller's SM49 (5.9 g)

References

External links

California Meteor Broke Speed Record for Atmospheric Entry
(

Scientific American ''Scientific American'', informally abbreviated ''SciAm'' or sometimes ''SA'', is an American popular science magazine. Many famous scientists, including Albert Einstein and Nikola Tesla, have contributed articles to it. In print since 1845, it i ...

December 20, 2012)
Sutter's Mill Meteorite: a Californian Treasure Discovered by SETI/NASA Researchers
( Google Hangout chat 20 December 2012) *
Analysis of Sutter's Mill fragments reveals organic compounds not seen in other meteorites
(Phys.org : 10 Sept 2013)

(Mr-Meteorite Ruben Garcia purchased 8.5 gram Sutter Mill Meteorite with broken fusion crust)
Patient hunters find more meteorites from California fall
(AstroBob April 29, 2012)
Robert Wards 44 gram findSteve Arnold (meteorhntr) photos of 0.38g SM slice
(oriented 9.9g)
Sutter's Mill photos at ASU
(SM6, SM8, SM38, SM41, SM49
Video of the daylight California fireball
(Phil Plait 31 May 2012)
CAMS
News blog (CAMS is an automated video surveillance of the night sky in search of meteors to validate minor showers in the IAU Working List of Meteor Showers) *

Strewn field The term strewn field indicates the area where meteorites from a single fall are dispersed. It is also often used for the area containing tektites produced by large meteorite impact.''Tektites in the geological record: showers of glass from the sky ...

maps:
Coloma, CA Strewn Field Map
(Marc Fries) **Sutter Mil
strewn field
(Jim Wooddell)

(SacBee: Last Modified: Monday, May. 7, 2012)
Sutter Mill Meteorite Find Tally
(An updated tally of Sutter Mill meteorites found - Mike Gilmer)
Official Sutter Mill Meteorite Hunt Page - NASA/SETI
(Dr. Jenniskens' Official Sutter Mill Find Data Page) {{2012 in space Meteorites found in the United States Modern Earth impact events 2012 in space 2012 in California Geology of California April 2012 events in the United States

History

Comparisons

Examples

See also

References

External links