7.3: Dating Planetary Surfaces
At the time that Darwin’s On the Origin of Species was published, the earth was “scientifically” determined to be million years old. By , it was found to be 1. In , science firmly established that the earth was 3. Finally in , it was discovered that the earth is “really” 4. In these early studies the order of sedimentary rocks and structures were used to date geologic time periods and events in a relative way. At first, the use of “key” diagnostic fossils was used to compare different areas of the geologic column. Although there were attempts to make relative age estimates, no direct dating method was available until the twentieth century. However, before this time some very popular indirect methods were available. For example, Lord Kelvin had estimated the ages of both the Earth and the Sun based on cooling rates. The answer of 25 million years deduced by Kelvin was not received favorably by geologists.
FAQ – Mars 1. What are the differences in interior composition between Earth and Mars? Earth and Mars have fairly similar compositions, with roughly equal amounts of rock and iron in their interiors. Earth has large amounts of granite in its crust, which Mars appears to lack.
Dating planetary surfaces using the small crater populations requires the separation of primaries from secondaries which is extremely difficult. The results also show that other factors, such as different target properties and the subjective identification of impact craters by different crater counters, may also affect crater counting results.
So too shall I test the Unforgiven. Cypher is a being wrapped in shadow, an entity whose every move is cloaked in mystery. His motives and methods are themselves an enigma; even the name or title by which he is known seems to conceal something, although whether it is a metaphor or yet another conundrum is unknown. To the Imperium at large, Cypher is either wholly unknown, or a being of shadowy rumour that seems to be somehow connected to or sought by the Dark Angels and their Successor Chapters.
To the Unforgiven , Cypher is a being of legend and untold speculation. Cypher is the one whom the Masters of the Dark Angels seek above all others, for he is their most hated foe. The Dark Angels have been chasing Cypher since the catastrophic fall of Caliban , and he has eluded capture for nearly ten thousand standard years. During that time, Cypher has appeared in each of the five Segmentums , materialising as if from nowhere.
Wherever he surfaces, he brings with him death and destruction, although whether he is the culprit or merely a herald of woe is unclear. Cypher seldom instigates the violent acts that invariably occur when he is present; it is rather that he seems to act as a catalyst, fanning the hatred and mistrust of those around him into a raging fire. Cypher vanishes from the scene as abruptly as he arrives.
Worlds burn in his wake. Besides havoc and ruin, there is another trail that Cypher leaves behind; legend and rumour abound after the passage of the mysterious robed figure. The intrigue over his rapid departure is magnified by the inevitable wave of ensuing questions.
Planetary Science & Exploration
My research approach is to use multiple techniques to characterise extra-terrestrial materials either in terms of composition or in terms of chronology. One of my main specialities is the analysis of meteorites using noble gases He-Xe and halogens Cl, Br, I , and chronology studies e. More recently, I have been working on overall compositional studies of meteorites at micro- and nanometer- scales Current research areas include: The chronometry planetary regoliths, with an aim to contribute to solving important scientific questions such as:
Dating Planetary Surfaces Learning Objectives. By the end of this section, you will be able to: Explain how astronomers can tell whether a planetary surface is geologically young or old; Describe different methods for dating planets; How do we know the age of the surfaces we see on planets and moons? If a world has a surface (as opposed to.
Space and planetary geology Space and planetary geology comprises that branch of the discipline of geology that applies basic scientific principles to the study of the origin, development, and characteristics of solar system objects such as planets, satellites, asteroids, comets , meteorites, and interplanetary dust particles. On Earth , space and planetary geology investigations are generally limited to impact craters and impact effects upon Earth, and to the study of Earth as an analogue for other planets and their processes.
As technology progresses in the future, the field of space and planetary geology will likely expand to include extra- solar system objects as well. Space and planetary geology is also called astrogeology. Space and planetary geology has it origins in telescopic observations of planets, satellites, and comets and in the study of meteorites. Telescopic maps of the Moon date from early work c. The first true lunar geologic map was that of Michael van Langren — , which he completed in After this, many other such telescopic maps were made of the Moon over the next three centuries.
During the period to , several telescopic maps of topographic and geological features of Mercury and Mars were produced. The most famous of these were maps by Percival Lowell — , which showed his interpreted “canals” on Mars. Meteoritics, which is the study of meteorites and their origins, traces its origin as a science back to the German physicist Ernst Florens Chladni — Chladni proposed convincing but highly debated arguments c.
That small objects asteroids were orbiting the Sun was confirmed shortly thereafter — by a group of Italian astronomers dubbed the “celestial police,” who discovered the first four known asteroids, Ceres, Pallas, Juno, and Vesta.
Department of Earth Sciences
Contrary to the usual representation of Kelvin’s argument, the observed thermal gradient of the Earth’s crust would not be explained by the addition of radioactivity as a heat source. More significantly, mantle convection alters how heat is transported within the Earth, invalidating Kelvin’s assumption of purely conductive cooling. Global internal heat flow[ edit ] Cross section of the Earth showing its main divisions and their approximate contributions to Earth’s total internal heat flow to the surface, and the dominant heat transport mechanisms within the Earth.
The respective mean heat flows of continental and oceanic crust are The fluidity of a material is proportional to temperature; thus, the solid mantle can still flow on long time scales, as a function of its temperature  and therefore as a function of the flow of Earth’s internal heat.
Established approaches to dating planetary surfaces through the analysis of a superposed crater population rely on the technique of binning the measured crater diameters, and attempting to use the thus divided data to resolve the characteristic shape and density of the accumulating crater population (Hartmann b; Crater Analysis Techniques.
What the Moon’s craters tell us about Earth’s past climate You might be surprised to learn that studying craters on the Moon can tell us about ancient Earth. Craters punctuate the surface of the Moon, while the surface of the Earth lacks them. Craters form when asteroids impact planetary bodies. The rate at which craters form depends on the availability of asteroids that hit a planetary body.
Earth and the Moon exist in the same space in the solar system, so have been exposed to the same impactor population. Was the Earth simply lucky enough to have escaped being hit by asteroids that ravaged the surface of the moon? Since early in the space program, scientists have recognized that this difference has to do with Earth’s active geology. Earth has weather and tectonics that act to destroy impact craters.
But the story may not be so simple. Bottke shared several new ideas about why these craters might be missing from Earth’s geologic record. Bottke applied a new method for dating lunar craters. He focused on lunar craters 10 kilometers in diameter or larger, comparing them with similar-sized craters diameters exceeding 20 kilometers on Earth.
June 15, In this image, each red dot represents one such crater. The new Martian crater atlas is the largest single database ever compiled of impacts on a planet or moon in our solar system, researchers said.
The isotopic method of determining absolute age is the most accurate and desirable way of dating planetary surfaces, but collecting and returning rock samples from distant planets and satellites is a difficult and expensive endeavor.
Now, for the first time, researchers have successfully determined the age of a Martian rock—with experiments performed on Mars. The work, led by geochemist Ken Farley of the California Institute of Technology Caltech , could not only help in understanding the geologic history of Mars but also aid in the search for evidence of ancient life on the planet. However, shortly before the rover left Earth in , NASA’s participating scientist program asked researchers from all over the world to submit new ideas for experiments that could be performed with the MSL’s already-designed instruments.
Keck Foundation Professor of Geochemistry and one of the 29 selected participating scientists, submitted a proposal that outlined a set of techniques similar to those already used for dating rocks on Earth, to determine the age of rocks on Mars. Findings from the first such experiment on the Red Planet—published by Farley and coworkers this week in a collection of Curiosity papers in the journal Science Express—provide the first age determinations performed on another planet. The paper is one of six appearing in the journal that reports results from the analysis of data and observations obtained during Curiosity’s exploration at Yellowknife Bay—an expanse of bare bedrock in Gale Crater about meters from the rover’s landing site.
How Good Are Those Young-Earth Arguments?
Caltech Resources About the Division of Geological and Planetary Sciences In the Division of Geological and Planetary Sciences GPS , faculty and students study the earth and other planets in order to understand their origin, composition, and development. Their approach to these problems relies heavily on fundamental science and on interdisciplinary collaborations with colleagues from across Caltech, as well as at the U.
Geological Survey and the Jet Propulsion Laboratory. GPS’s seamless integration of both earth and planetary sciences within one division gives it a unique perspective on our world and our universe, providing its researchers with the opportunity to apply lessons learned from the earth’s geological past to the study of other planets throughout the solar system, and vice versa.
Ever since the division’s beginnings in , its researchers and faculty have worked at the forefront of their fields, shaping how we view and interact with our world as well as with other worlds. Their work has led to a greater understanding of subjects ranging from earthquake mechanics and analysis to geological dating and history, climate science, atmospheric physics, and the origin of planetary surfaces and atmospheres, among other areas.
High-precision potassium measurements using laser-induced breakdown spectroscopy under high vacuum conditions for in situ K–Ar dating of planetary surfaces.
Moon Dust and the Age of the Solar System Answers in Genesis , the leading young-earth creationist ministry, disowns cosmic dust arguments. The most amazing thing about the cosmic dust argument is that it is still being used! It has coasted along on obsolete evidence, and nothing but obsolete evidence, for the last 25 years!!
It nicely illustrates how creationists borrow from each other and never do any outside reading. The obsolescence of this argument has been brought out in numerous debates and published in countless books, journals, and newsletters. It can be discovered by anyone who exercises his or her library card. It’s not a state secret!
Relative and absolute ages in the histories of Earth and the Moon: The Geologic Time Scale
Erik Rotheim, Norway, De fabrica corporis humani, an illustrated systematic study of the human body Andreas Vesalius, Belgium, ; comparative: Emil von Behring, Germany, Felix Hoffman, Germany,
Sep 01, · Dating by measurement of impact crater frequencies developed in the past years primarily on the basis of the data from the missions to the Moon and Mars.
History of Technology Heroes and Villains – A little light reading Here you will find a brief history of technology. Initially inspired by the development of batteries, it covers technology in general and includes some interesting little known, or long forgotten, facts as well as a few myths about the development of technology, the science behind it, the context in which it occurred and the deeds of the many personalities, eccentrics and charlatans involved.
You may find the Search Engine , the Technology Timeline or the Hall of Fame quicker if you are looking for something or somebody in particular. Scroll down and see what treasures you can discover. Background We think of a battery today as a source of portable power, but it is no exaggeration to say that the battery is one of the most important inventions in the history of mankind.
Volta’s pile was at first a technical curiosity but this new electrochemical phenomenon very quickly opened the door to new branches of both physics and chemistry and a myriad of discoveries, inventions and applications. The electronics, computers and communications industries, power engineering and much of the chemical industry of today were founded on discoveries made possible by the battery.
Pioneers It is often overlooked that throughout the nineteenth century, most of the electrical experimenters, inventors and engineers who made these advances possible had to make their own batteries before they could start their investigations.
Problems with the U-Pb Radioisotope Dating Methods—1. Common Pb
Since then, no US mission has touched down there to collect scientific data. That could soon change. Take LADEE, which detected traces of water in the lunar atmosphere that were probably carried there by meteorites. Researchers need more detailed observations to better understand how water moves around on the lunar surface and into the atmosphere. Nature , March 6 , doi: Still, many expect NASA to call in the coming months for proposals that rely on small commercial landers.
A standard method for inferring the ages of planetary surfaces continues to be plagued by bad assumptions. We’ve reported before about the problem of “secondary craters” in crater-count dating.*.
The derivation of the above is as follows: Since the most redundantly observed Cydonia ratio is 0. This feature also now seems to mark an equally important latitude: The terminus of this wedge, together with the NW corner of the pyramid, are the only two points on the pyramid that, when connected, denote a line of latitude see Fig. Again, putting this in simple terms: This discovery only underscores the importance apparently attached to “circumscribed tetrahedral geometry” in the construction of Cydonia — raising the important question: If this is indeed “the message of Cydonia,” crafted by what Mars’ hostile environment strongly implies was a visiting interstellar culture Hoagland, , then what could have been its purpose?
To communicate the “importance” of tetrahedral geometry itself!
#LPSC2018: What the Moon’s craters tell us about Earth’s past climate
Visual spectrum This site, closely coupled to The Natures of the Stars and The Hertzsprung- Russell HR Diagram , provides an introduction to the spectra of stars and allied celestial objects. Here we examine the principal way in which astronomers have learned so much about the stars. Spectra has been translated into Romanian.
The visual spectrum Pass sunlight through a triangular prism or bounce it off the finely grooved surface of a compact audio disk and see it break merrily into a band of pure sparkling color, its “spectrum,” familiar in the colors of a rainbow, in light glittering from newly fallen snow, in the rings and haloes around a partly- clouded Sun and Moon, in the flash of a cut diamond, and in so many other facets of nature.
Dating Planetary Surfaces. Learning Objectives. By the end of this section, you will be able to: Explain how astronomers can tell whether a planetary surface is geologically young or old; Describe different methods for dating planets; How do we know the age of the surfaces we see on planets and moons? If a world has a surface (as opposed to.
Ancient rift valleys — closeup artist’s concept. Distribution of mare basalts[ edit ] This section needs additional citations for verification. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. November Learn how and when to remove this template message A global albedo map of the Moon obtained from the Clementine mission.
The dark regions are the lunar maria, whereas the lighter regions are the highlands. There are many common misconceptions concerning the spatial distribution of mare basalts. Since many mare basalts fill low-lying impact basins, it was once assumed that the impact event itself somehow caused the volcanic eruption. Initial mare volcanism generally seems to have begun within million years of basin formation. However, in a reference frame rotating with the Moon, the centrifugal acceleration the Moon is experiencing is exactly equal and opposite to the gravitational acceleration of the Earth.
There is thus no net force directed towards the Earth. The Earth tides do act to deform the shape of the Moon, but this shape is that of an elongated ellipsoid with high points at both the sub- and anti-Earth points. As an analogy, one should remember that there are two high tides per day on Earth, and not one.