Posted on 01/25/2019 10:44:41 AM PST by ETL
A chunk of Earth that could be 4.1 billion years old and is described as the planet's "oldest rock," may have been found and dug up on the Moon by Apollo astronauts, according to a new study.
The possible relic was discovered and dug up in 1971 and scientists believe that it was sent off Earth, thanks to a powerful impact, possibly an asteroid or a comet. After colliding with the Moon (which at the time was three times closer to the Earth than it is now), it mixed with other lunar surface materials.
"It is an extraordinary find that helps paint a better picture of early Earth and the bombardment that modified our planet during the dawn of life," said study co-author David Kring, a Universities Space Research Association (USRA) scientist at the Lunar and Planetary Institute in Houston, in a statement.
Analyzing lunar samples collected by the Apollo 14 mission, the researchers found that the rock consisted of 0.08 ounces of quartz, feldspar and zircon, minerals that are fairly commonplace on Earth but "highly unusual on the Moon," according to the statement.
(Excerpt) Read more at foxnews.com ...
The oldest dated rocks on Earth, as an aggregate of minerals that have not been subsequently broken down by erosion or melted, are more than 4 billion years old, formed during the Hadean Eon of Earth’s geological history.
Such rocks are exposed on the Earth’s surface in very few places. Some of the oldest surface rock can be found in the Canadian Shield, Australia, Africa and in a few other old regions around the world. The ages of these felsic rocks are generally between 2.5 and 3.8 billion years. The approximate ages have a margin of error of millions of years.
In 1999, the oldest known rock on Earth was dated to 4.031 ±0.003 billion years, and is part of the Acasta Gneiss of the Slave craton in northwestern Canada.[1]
Researchers at McGill University found a rock with a very old model age for extraction from the mantle (3.8 to 4.28 billion years ago) in the Nuvvuagittuq greenstone belt on the coast of Hudson Bay, in northern Quebec;[2] the true age of these samples is still under debate, and they may actually be closer to 3.8 billion years old.[3]
Older than these rocks are crystals of the mineral zircon, which can survive the disaggregation of their parent rock and be found and dated in younger rock formations.
In January 2019, NASA scientists reported the discovery of the oldest known Earth rock – on the Moon.
Apollo 14 astronauts returned several rocks from the Moon and later, scientists determined that a fragment from one of the rocks contained “a bit of Earth from about 4 billion years ago.” The rock fragment contained quartz, feldspar, and zircon, all common on the Earth, but highly uncommon on the Moon.[4]
Of over 61,000 meteorites that have been found on Earth, 224 were identified as Martian as of January 2019.[1]
These meteorites are thought to be from Mars because they have elemental and isotopic compositions that are similar to rocks and atmosphere gases analyzed by spacecraft on Mars.[3]
In October 2013, NASA confirmed, based on analysis of argon in the Martian atmosphere by the Mars Curiosity rover, that certain meteorites found on Earth thought to be from Mars were indeed from Mars.[4]
The term does not refer to meteorites found on Mars, such as Heat Shield Rock.
On January 3, 2013, NASA reported that a meteorite, named NWA 7034 (nicknamed “Black Beauty”), found in 2011, in the Sahara desert, was determined to be from Mars and found to contain ten times the water of other Mars meteorites found on Earth.[2]
The meteorite contains components as old as 4.42 ± 0.07 Ga (billion years),[5] and was heated during the Amazonian geologic period on Mars.[6]
Ping.
1 Discovery
2 Transfer to Earth
3 Scientific relevance
4 Observation history
5 Private ownership
6 See also
7 References
8 External links
Discovery
In January 1982, John Schutt, leading an expedition in Antarctica for the ANSMET program, found a meteorite that he recognized to be unusual.
Shortly thereafter, the meteorite now called Allan Hills 81005 was sent to Washington, DC, where Smithsonian Institution geochemist Brian Mason recognized that the sample was unlike any other known meteorite and resembled some rocks brought back from the Moon by the Apollo program.[2]
Several years later, Japanese scientists[who?] recognized that they had also collected a lunar meteorite, Yamato 791197, during the 1979 field season in Antarctica. As of August 2017, about 306 lunar meteorites have been discovered,[3] perhaps representing more than 30 separate meteorite falls (i.e., many of the stones are “paired” fragments of the same meteoroid).[4]
The total mass is more than 190 kilograms (420 lb).[4] All lunar meteorites have been found in deserts; most have been found in Antarctica, northern Africa, and the Sultanate of Oman. None have yet been found in North America, South America, or Europe.[5]
Lunar origin is established by comparing the mineralogy, the chemical composition, and the isotopic composition between meteorites and samples from the Moon collected by Apollo missions.
Transfer to Earth
Most lunar meteorites are launched from the Moon by impacts making lunar craters of a few kilometers in diameter or less.[6] No source crater of lunar meteorites has been positively identified, although there is speculation that the highly anomalous lunar meteorite Sayh al Uhaymir 169 derives from the Lalande impact crater on the lunar nearside.[7][8]
Cosmic-ray exposure history established with noble-gas measurements have shown that all lunar meteorites were ejected from the Moon in the past 20 million years. Most left the Moon in the past 100,000 years.
After leaving the Moon, most lunar meteoroids go into orbit around Earth and eventually succumb to Earth’s gravity. Some meteoroids ejected from the Moon get launched into orbits around the Sun. These meteoroids remain in space longer, but eventually intersect the Earth’s orbit and land.[9]
If the moon used to be 1/3 of the distance away from Earth as it is now, didn’t that mean that the tides were much more extreme ?
Early Earth suffered constant threat of attack from leftover planet-building material. From about 4.5 to 3.8 billion years ago, failed planets and smaller asteroids slammed into larger worlds, scarring their surface.
Near the end of the violence, during a period known as the Late Heavy Bombardment, impacts in the solar system may have increased. The increased activity most likely came from the movement of the giant planets, which sent debris raining down on the smaller rocky worlds.
Earth bears relatively few scars from its violent youth because weathering and plate tectonics have renewed its surface. But the three other rocky planets (Mercury, Venus and Mars), as well as the moon, still carry the signs of the increased collisions.
By using crater counting methods to estimate ages on these scarred worlds, scientists have been able to estimate time frames for material slamming into their surface. Samples collected by Apollo moonwalkers also contain the chemical signatures from different meteorites. Together, the evidence indicates that impacts increased about 3.8 to 3.9 billion years ago, during the Late Heavy Bombardment, which is thought to have lasted between 20 million to 200 million years.
Even the asteroid belt may show some wear and tear, with traces of chemicals that bind tightly to iron found on their surface rather than beneath it. In addition to finding that the asteroids took longer to accrete than previously suspected, recent research revealed that "there also must have been lots of small or medium-sized bodies present in the solar system for these collisions to have occurred over a range of time scales," Christopher Dale, a researcher at England's Durham University, told Space.com previously.
The LHB may have been key to delivering water to Earth. Models show that when the planet formed, it was too hot to hold onto the life-giving liquid. Instead, water must have been delivered by other means.
In the past, comets were thought to be a significant source of the planet's water. If something stirred up the debris in the outer solar system — and models suggest that the early motions of Uranus and Neptune could have flung material inward — the ice-rich comets could have deposited water on Earth's surface, while the planet's atmosphere kept it from evaporating.
However, studies of comets, including Halley's Comet and Comet 67P/Churyumov-Gerasimenko, have revealed that most of them seem to carry a different concentration of heavy water. While a normal water molecule is made of two hydrogen and one oxygen atom, heavy water has a hydrogen atom with an extra neutron in its nucleus, called deuterium. If Earth's water had come from comets, its deuterium-to-hydrogen ratio should be higher than it is today.
"This probably rules out Kuiper belt comets from bringing water to Earth," Kathrin Altwegg, principle investigator of the ROSINA mass spectrometer on board the European Space Agency's Rosetta mission to Comet 67P/C-G, said at a 2014 press conference.
Asteroids currently are the most likely suspect for delivering water to the planet. The small rocky bodies could have carried water and organic material to the surface during the LHB as they slammed into the surface.
"Today's asteroids have very little water — that's clear," Altwegg said. "But that was probably not always the case. During the Late Heavy Bombardment 3.8 billion years ago, at that time, asteroids could have had much more water than they could now."
Those asteroids could have pounded the planets for even longer than originally believed. Although Earth's scars have long since been covered, researchers can study millimeter- to centimeter-thick layers of rock droplets known as spherules.
"Spherule layers, if preserved in the geologic record, provide information about an impact even when the source crater cannot be found," Brandon Johnson, of Purdue University, told Space.com. Johnson led a study that used models to deduce the impact sizes based on the properties of spherule beds.
"Some of the asteroids that we infer were about 40 kilometers (24.8 miles) in diameter, much larger than the one that killed off the dinosaurs about 65 million years ago that was about 12 to 15 kilometers (7.4 to 9.3 miles)," said co-author Jay Melsoh at Purdue University.
But while giant impacts bring with them the idea of impending doom, other studies show that life could have still survived — or even flourished — in microbial form. Underground microbes would have flourished as their habitats increased thanks to the impacts.
"Even under the most extreme conditions we imposed, Earth would not have been completely sterilized by the bombardment," said lead author Oleg Abramov, of the University of Colorado, Boulder.
But a new contender may be on the rise. Impact researcher William Bottke, of the Southwest Research Institute in Colorado, thinks failed planets may have played an important role.
"We have evidence for two early-bombardment populations and a time difference between them — a late one, plausibly made by escapees from the asteroid belt, and an early one from elsewhere," Bottke said.
Bottke suspects that failed young planets, or planetesimals, may have contributed to the impacts on the back side of the moon. These planetesimals would have been far larger than the objects in the asteroid belt, and would have done significant damage as they crashed into the rocky inner solar system worlds.
If asteroids caused the LHB, the uptick in activity was most likely came from the movement of the giant planets. According to a recent model known as Grand Tack, Jupiter and Saturn moved into the inner solar system before tacking like a sail boat and returning to their final orbits farther out. Along the way, they would have scattered any debris found in an early asteroid belt, sending it flying toward Mercury, Venus, Earth, and Mars.
Another model could explain the both incoming protoplanets and a handful of comets, which may have contributed organic material. Known as the Nice model, it calls for Neptune and Uranus to change places, sending the icy material that formed near them flying. Some of it would form the Kuiper Belt, the outer region of the solar system where Pluto orbits, while others would travel inward towards the rocky worlds.
The two models work well together, so oth could explain the impacts that scarred early Earth.
Yes, and I have heard that the moon was, at one time, 1/5oth of its current distance away from earth. Imagine the impact on tides and everything else back then. Consider: the moon lifts the ocean 6 feet at its current distance.
Or the whole article is based on some faulty science.
looks like the lucky charms leprechaun:-)
Thanks Army Air Corps.
After colliding with the Moon (which at the time was three times closer to the Earth than it is now), it mixed with other lunar surface materials.
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Charles P. Sonett, Regents Professor Emeritus of planetary sciences at The University of Arizona in Tucson, and Aramais Zakharian, a graduate student at the UA Lunar and Planetary Laboratory, collaborated with geologists in the analysis, published today (July 5) in Science. Their co-authors are Eric P. Kvale of the Indiana Geological Survey, Marjorie A. Chan of the University of Utah, and Timothy M. Demko of Colorado State University.
They studied sediments left by tides preserved in four exceptional formations: the Big Cottonwood Formation near Salt Lake City, Utah, deposited 900 million years ago; the Elatina Formation near Adelaide, Australia, deposited 650 million years ago; the Pottsville Formation of northern Alabama from 312 million years ago; and Indiana’s Mansfield Formation from 305 million years ago. The ages of these formations are known by their geological context.
That Earth’s tides are created by the pull of mostly the moon’s gravity, and to a lesser degree by the sun’s gravity, is well known. Scientists use the laws of celestial mechanics to calculate how this gravitational pull causes the Earth to spin slower on its axis — lengthening the Earth day. They further calculate how the loss of Earth’s rotational angular momentum and energy increases the size of the moon’s orbit, lengthening the distance between Earth and moon.
But physical evidence that measures actual dynamics between Earth and moon has been hard to come by. Early modern-day astronomers realized from 2,000-year-old records that the timing of lunar eclipses was changing, so Earth-and-moon dynamics were altering, Sonett noted in an interview. In the 1960s and 1970s, there was a flurry of scientific interest in what physical evidence for changes in the length of Earth’s day might exist in the fossil coral record. NASA’s Apollo program focused further attention, especially when astronauts left a laser reflector on the moon that was used to measure the increasing distance between Earth and moon at 3.82 centimeters, or about 1.5 inches, each year.
The discovery of “tidalites” from southern Australia in the late 1980s alerted scientists like Sonett to a new way to examine how the moon’s orbit has evolved through time.
Layers of tide-deposited sedimentary rock, called tidalites, are records of daily tides. Dark bands that periodically occur in the layers clearly mark the semi-monthly “neap” tides, or lower tides that form during the waxing and waning phases of the moon, i.e., when the moon is farthest from aligning with the sun and Earth. Lighter areas between the dark bands mark the semi-monthly “spring” tides, or the higher tides that form when sun, Earth and moon are most nearly aligned, at full moon and new moon.
The scientists used a binocular microscope fitted with a micrometer in counting the thicknesses of neap-spring intervals in cores taken from the formations. The record of neap-spring tide bands shows a lengthening monthly lunar cycle over the past 900 million years. Sonett and Zakharian used the record to calculate how much farther away from Earth the moon has moved since late Proterozoic times. The rate of the moon’s retreat from Earth recorded in tidalites is consistent with the modern rate of lunar retreat measured by the Apollo experiments, the authors conclude.
It took only about 18 hours for Earth to make a complete rotation on its axis 900 million years ago, the authors also conclude. They analyzed how much energy the Earth has lost to the moon since that time, and how much energy the Earth has lost through tidal friction. Tidal friction is heat lost as oceans drag across sections of shallow ocean floor and layers of rock rub together as they rise and fall.
Years were 481 days long in Proterozoic times, they add.
Given its present-day rate of retreat, the moon eventually would reach synchronous orbit with Earth in about 15 billion years, Zakharian said in an interview. In synchronous orbit, the moon and Earth would orbit together as planet and satellite in fixed position, locked face-to-face, about 560,000 kilometers (336,000 miles) apart. The moon now is about 384,000 kilometers (240,000 miles) away.
Not that this is likely to happen, Sonett and Zakharian say: 15 billion years is older than the age of the universe. It’s more probable that our sun will change into a red giant star, or that a major asteroid will strike Earth, before then.
https://www.eurekalert.org/pub_releases/1996-07/UoA-TRTM-050796.php
To say nothing of the effects on the Earth’s crust. I wonder what the period of rotation was. And it’s velocity.
Imagine the moon 3 times closer. The ocean tides would be immense. The earthquakes never ending.
How long would it take the moon to orbit the earth if it was 3 times closer?
Thank goodness its there instead of here causing ocean floods.
Interesting photo and video of what the moon looked like from earth so long ago. The video says 5 minutes to cross the sky.
https://slate.com/technology/2014/05/close-encounter-what-if-the-moon-orbited-much-closer-to-earth.html
Maybe False Science is more accurate - I agree.
All a WAG (”Wild A** Guess), not science. Yes, a possibility, but science? No.
Because there are millions of other possibilites. Could be there are lots of asteroids somewhere who have composition very close to the earth, the moon, Mars - and other planets......and who knows what is beyond our solar system - no one.
Thanks
Sorry about the late reply.
This is actually easy to do, just use Kepler’s famous Third Law:
P squared / R cubed = a constant for any planet or sun.
where P = orbital period
and R = orbital diameter.
Example - Mars’ orbit is 1.52x Earth’s; So if you cube 1.52, then take the square root, you get that Mars’ orbital period is 1.87x Earth’s, or 684 days.
So in this case, cube 0.3333, then take the square root, and multiply it by the Moon’s current period (about 29 days), and you get - just under 6 days for 1 orbit back then.
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