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MARS DURING the PRE-NOACHIAN. J. C. Andrews-Hanna1 and W. B. Bottke2, 1Lunar and Planetary La- Boratory, University of Arizona
Fourth Conference on Early Mars 2017 (LPI Contrib. No. 2014) 3078.pdf MARS DURING THE PRE-NOACHIAN. J. C. Andrews-Hanna1 and W. B. Bottke2, 1Lunar and Planetary La- boratory, University of Arizona, Tucson, AZ 85721, [email protected], 2Southwest Research Institute and NASA’s SSERVI-ISET team, 1050 Walnut St., Suite 300, Boulder, CO 80302. Introduction: The surface geology of Mars appar- ing the pre-Noachian was ~10% of that during the ently dates back to the beginning of the Early Noachi- LHB. Consideration of the sawtooth-shaped exponen- an, at ~4.1 Ga, leaving ~400 Myr of Mars’ earliest tially declining impact fluxes both in the aftermath of evolution effectively unconstrained [1]. However, an planet formation and during the Late Heavy Bom- enduring record of the earlier pre-Noachian conditions bardment [5] suggests that the impact flux during persists in geophysical and mineralogical data. We use much of the pre-Noachian was even lower than indi- geophysical evidence, primarily in the form of the cated above. This bombardment history is consistent preservation of the crustal dichotomy boundary, to- with a late heavy bombardment (LHB) of the inner gether with mineralogical evidence in order to infer the Solar System [6] during which HUIA formed, which prevailing surface conditions during the pre-Noachian. followed the planet formation era impacts during The emerging picture is a pre-Noachian Mars that was which the dichotomy formed. less dynamic than Noachian Mars in terms of impacts, Pre-Noachian Tectonism and Volcanism: The geodynamics, and hydrology. crust within each of the southern highlands and north- Pre-Noachian Impacts: We define the pre- ern lowlands is remarkably uniform in thickness, aside Noachian as the time period bounded by two impacts – from regions in which it has been thickened by volcan- the dichotomy-forming impact and the Hellas-forming ism (e.g., Tharsis, Elysium) or thinned by impacts impact. -
2020-2021 Districtwide School Year Calendar
FINAL 2020 – 2021 Districtwide School Year Calendar AUGUST FEBRUARY 2020-21 Calendar M T W T F M T W T F 3 4 5 6 7 1 2 3 4 5 Aug 17 Professional Meeting Day. No Students 8 Aug 18 -21 Staff Professional Development Day. 10 11 12 13 14 9 10 11 12 M No Students. Aug 24 Schools Open. Students Report. 17 18 19 20 21 15 16 17 18 19 Sept 7 Labor Day. Holiday. Schools Closed Sep 14 Midterm Week 24 25 26 27 28 22 23 24 25 26 Sep 21 –Oct 9 Fall Gifted Screening 31 Sep 28- Oct 9 INVIEW / Terra Nova (Elementary) Oct 14 PSAT (High Schools) Oct 16 End of First Quarter. Students Report. SEPTEMBER MARCH (39 Instructional Days, 44 Staff Days). M T W T F M T W T F Oct 21 – 27 3rd Grade Fall ELA. 1 2 3 4 1 2 3 4 5 Nov 2 Conference Comp Day –School Closed Nov 3 Election Day – Conference Day. 7 8 9 10 11 8 9 10 11 12 Q No Students. 14 M 15 16 17 18 15 16 17 18 19 Nov 9 Midterm Week 21 22 23 24 25 22 23 24 25 26 Nov 11 Veterans’ Day. Holiday Observance. Schools Closed. 28 29 30 29 30 31 Nov 25 Conference Day. No Students. Nov 26 Thanksgiving. Holiday Observance. OCTOBER APRIL Nov 27 Schools Closed. Dec 1 – 11 Fall HS End of Course M T W T F M T W T F Dec 14 -18 Semester 1 Exams (High Schools) 1 2 1 2 Dec 18 End of Second Quarter. -
The Mathematics of the Chinese, Indian, Islamic and Gregorian Calendars
Heavenly Mathematics: The Mathematics of the Chinese, Indian, Islamic and Gregorian Calendars Helmer Aslaksen Department of Mathematics National University of Singapore [email protected] www.math.nus.edu.sg/aslaksen/ www.chinesecalendar.net 1 Public Holidays There are 11 public holidays in Singapore. Three of them are secular. 1. New Year’s Day 2. Labour Day 3. National Day The remaining eight cultural, racial or reli- gious holidays consist of two Chinese, two Muslim, two Indian and two Christian. 2 Cultural, Racial or Religious Holidays 1. Chinese New Year and day after 2. Good Friday 3. Vesak Day 4. Deepavali 5. Christmas Day 6. Hari Raya Puasa 7. Hari Raya Haji Listed in order, except for the Muslim hol- idays, which can occur anytime during the year. Christmas Day falls on a fixed date, but all the others move. 3 A Quick Course in Astronomy The Earth revolves counterclockwise around the Sun in an elliptical orbit. The Earth ro- tates counterclockwise around an axis that is tilted 23.5 degrees. March equinox June December solstice solstice September equinox E E N S N S W W June equi Dec June equi Dec sol sol sol sol Beijing Singapore In the northern hemisphere, the day will be longest at the June solstice and shortest at the December solstice. At the two equinoxes day and night will be equally long. The equi- noxes and solstices are called the seasonal markers. 4 The Year The tropical year (or solar year) is the time from one March equinox to the next. The mean value is 365.2422 days. -
2021-22 Official District Calendar
Perrysburg AMENDED JUNE 21, 2021 Public Schools Tuesday August 10 HPI - Grade 6 orientation, Junior High Orientation 2021-2022 Wednesday August 11 JH &HPI (grade 5) orientation Thursday August 12 Teacher Inservice School Year Calendar Friday August 13 Teacher Inservice Monday August 16 Teacher Inservice/Workday Tuesday-Thursday August 17-19 Elementary - Jacket Jump Start Appointments Tuesday August 17 HS-Freshman only attend, JH-Grade 8 only attend, HPI-Grade 6 only attend AUGUST 2021 SEPTEMBER 2021 OCTOBER 2021 Wednesday August 18 HS-Freshman only attend, JH-Grade 7 only attend, HPI-Grade 5 only attend M T W T F M T W T F M T W T F Thursday August 19 All High School, Junior High and HPI attend school 2 3 4 5 6 1 2 3 1 Thursday August 19 High School Open House - evening Elementary - First day 9 10 11 12 13 6 7 8 9 10 4 5 6 7 8 Friday August 20 Monday August 23 Preschool First Day 16 17 18 19 20 13 14 15 16 17 11 12 13 14 15 1 Thursday August 26 Junior High Open House - evening 23 24 25 26 27 20 21 22 23 24 18 19 20 21 22 Monday September 6 Labor Day - No School Preschool-12 30 31 27 28 29 30 25 26 27 28 29 Thursday September 23 High School Evening Conferences NOVEMBER 2021 DECEMBER 2021 JANUARY 2022 Friday October 15 End of first quarter M T W T F M T W T F M T W T F Monday & Wed. -
Hutton, Kelvin, and the Great Earth Debates. • the Beginnings of Modern Geology “All Natural Processes That Affect the Earth’S Crust (Erosion, Deposition, • Ca
Chapter 1 The Science of Geology An Introduction to Geology • Geology - the science that pursues an understanding of planet Earth • Physical geology - examines the materials composing Earth and seeks to understand the many processes that operate beneath and upon its surface • Historical geology - seeks an understanding of the origin of “If there is an interesting place you want to go, there is Earth and its development interesting geology that you can study there” through time Mersin ophiolite, (Cappadocia, Central Turkey). Turkey The Science of Geology The Science of Geology 1.3: satellite image of Mt. Vesuvius, Italy. • Some historical views • Geology, people, and the environment of the Earth • Many important relationships exist between • Aristotle, 300 BC; people and the natural environment • James Ussher, ca. 1600, ‘Earth was created in Problems and issues 4004 BC;’ addressed by • Catastrophism geology include • Earth’s features formed through • Natural hazards, sudden and violent resources, world changes. ‘The Dog population growth, of and environmental Pompeii’ issues Dwelling in Goreme, Cappadocia The Science of Geology Hutton, Kelvin, and the great Earth debates. • The beginnings of modern geology “All natural processes that affect the Earth’s crust (erosion, deposition, • ca. 1780, James Huton’s volcanic eruptions, faulting, glaciation Theory of the Earth; etc.) operate with the same intensity • Uniformitarianism: “the and under the same set of physical processes that operate constraints now as in the geologic past.” today have operated in “(as to the age of Earth) we see no the past.” vestige of a beginning, no prospect of • a uniformitarian view of an end.” Earth requires a vast These points are incorrect - why? amount of time…. -
Critical Analysis of Article "21 Reasons to Believe the Earth Is Young" by Jeff Miller
1 Critical analysis of article "21 Reasons to Believe the Earth is Young" by Jeff Miller Lorence G. Collins [email protected] Ken Woglemuth [email protected] January 7, 2019 Introduction The article by Dr. Jeff Miller can be accessed at the following link: http://apologeticspress.org/APContent.aspx?category=9&article=5641 and is an article published by Apologetic Press, v. 39, n.1, 2018. The problems start with the Article In Brief in the boxed paragraph, and with the very first sentence. The Bible does not give an age of the Earth of 6,000 to 10,000 years, or even imply − this is added to Scripture by Dr. Miller and other young-Earth creationists. R. C. Sproul was one of evangelicalism's outstanding theologians, and he stated point blank at the Legionier Conference panel discussion that he does not know how old the Earth is, and the Bible does not inform us. When there has been some apparent conflict, either the theologians or the scientists are wrong, because God is the Author of the Bible and His handiwork is in general revelation. In the days of Copernicus and Galileo, the theologians were wrong. Today we do not know of anyone who believes that the Earth is the center of the universe. 2 The last sentence of this "Article In Brief" is boldly false. There is almost no credible evidence from paleontology, geology, astrophysics, or geophysics that refutes deep time. Dr. Miller states: "The age of the Earth, according to naturalists and old- Earth advocates, is 4.5 billion years. -
The Throughput Year Clock: Defining “One Year” for AB 705
The Throughput Year Clock: Defining “one year” for AB 705 December 2020 | www.rpgroup.org The term “throughput” refers to the percentage of a student cohort who complete a course sequence within a set period after having begun that sequence at the same point in time. Under AB 705 the set period for observing throughput rates is described in law as “one year”. While that time frame seems intuitive enough, the operational definition of “one year” (or the “year clock”) has varied somewhat across sources. For instance, the operational definition of the year clock used by MMAP has evolved over time and been refined. This document provides an overview of how the MMAP team defined the year clock prior to September 2020, as well as a revised definition of the year clock that the team implemented in September 2020. Additionally, it is argued that consistency across cohorts of students with different starting terms within reports is more critical than maintaining a problematic definition simply for future reports to use the same definition as historical reports. Previously Used Throughput Timeframes For the purposes of AB 705 research, a year has been defined as two primary terms plus one or two minor terms or three primary terms (for quarter-based colleges). A minor term such as summer or winter intersession may be included in the three primary term sequence because its inclusion is necessary to satisfy the three primary terms requirement. Summer is a minor term for both the quarter and semester systems, whereas winter intersession is only considered a minor term for semester systems. -
“Anthropocene” Epoch: Scientific Decision Or Political Statement?
The “Anthropocene” epoch: Scientific decision or political statement? Stanley C. Finney*, Dept. of Geological Sciences, California Official recognition of the concept would invite State University at Long Beach, Long Beach, California 90277, cross-disciplinary science. And it would encourage a mindset USA; and Lucy E. Edwards**, U.S. Geological Survey, Reston, that will be important not only to fully understand the Virginia 20192, USA transformation now occurring but to take action to control it. … Humans may yet ensure that these early years of the ABSTRACT Anthropocene are a geological glitch and not just a prelude The proposal for the “Anthropocene” epoch as a formal unit of to a far more severe disruption. But the first step is to recognize, the geologic time scale has received extensive attention in scien- as the term Anthropocene invites us to do, that we are tific and public media. However, most articles on the in the driver’s seat. (Nature, 2011, p. 254) Anthropocene misrepresent the nature of the units of the International Chronostratigraphic Chart, which is produced by That editorial, as with most articles on the Anthropocene, did the International Commission on Stratigraphy (ICS) and serves as not consider the mission of the International Commission on the basis for the geologic time scale. The stratigraphic record of Stratigraphy (ICS), nor did it present an understanding of the the Anthropocene is minimal, especially with its recently nature of the units of the International Chronostratigraphic Chart proposed beginning in 1945; it is that of a human lifespan, and on which the units of the geologic time scale are based. -
Golden Spikes, Transitions, Boundary Objects, and Anthropogenic Seascapes
sustainability Article A Meaningful Anthropocene?: Golden Spikes, Transitions, Boundary Objects, and Anthropogenic Seascapes Todd J. Braje * and Matthew Lauer Department of Anthropology, San Diego State University, San Diego, CA 92182, USA; [email protected] * Correspondence: [email protected] Received: 27 June 2020; Accepted: 7 August 2020; Published: 11 August 2020 Abstract: As the number of academic manuscripts explicitly referencing the Anthropocene increases, a theme that seems to tie them all together is the general lack of continuity on how we should define the Anthropocene. In an attempt to formalize the concept, the Anthropocene Working Group (AWG) is working to identify, in the stratigraphic record, a Global Stratigraphic Section and Point (GSSP) or golden spike for a mid-twentieth century Anthropocene starting point. Rather than clarifying our understanding of the Anthropocene, we argue that the AWG’s effort to provide an authoritative definition undermines the original intent of the concept, as a call-to-arms for future sustainable management of local, regional, and global environments, and weakens the concept’s capacity to fundamentally reconfigure the established boundaries between the social and natural sciences. To sustain the creative and productive power of the Anthropocene concept, we argue that it is best understood as a “boundary object,” where it can be adaptable enough to incorporate multiple viewpoints, but robust enough to be meaningful within different disciplines. Here, we provide two examples from our work on the deep history of anthropogenic seascapes, which demonstrate the power of the Anthropocene to stimulate new thinking about the entanglement of humans and non-humans, and for building interdisciplinary solutions to modern environmental issues. -
Geologic Time and Geologic Maps
NAME GEOLOGIC TIME AND GEOLOGIC MAPS I. Introduction There are two types of geologic time, relative and absolute. In the case of relative time geologic events are arranged in their order of occurrence. No attempt is made to determine the actual time at which they occurred. For example, in a sequence of flat lying rocks, shale is on top of sandstone. The shale, therefore, must by younger (deposited after the sandstone), but how much younger is not known. In the case of absolute time the actual age of the geologic event is determined. This is usually done using a radiometric-dating technique. II. Relative geologic age In this section several techniques are considered for determining the relative age of geologic events. For example, four sedimentary rocks are piled-up as shown on Figure 1. A must have been deposited first and is the oldest. D must have been deposited last and is the youngest. This is an example of a general geologic law known as the Law of Superposition. This law states that in any pile of sedimentary strata that has not been disturbed by folding or overturning since accumulation, the youngest stratum is at the top and the oldest is at the base. While this may seem to be a simple observation, this principle of superposition (or stratigraphic succession) is the basis of the geologic column which lists rock units in their relative order of formation. As a second example, Figure 2 shows a sandstone that has been cut by two dikes (igneous intrusions that are tabular in shape).The sandstone, A, is the oldest rock since it is intruded by both dikes. -
Chapter 8: Geologic Time
Chapter 8: Geologic Time 1. The Art of Time 2. The History of Relative Time 3. Geologic Time 4. Numerical Time 5. Rates of Change Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Geologic Time How long has this landscape looked like this? How can you tell? Will your grandchildren see this if they hike here in 80 years? The Good Earth/Chapter 8: Geologic Time The Art of Time How would you create a piece of art to illustrate the passage of time? How do you think the Earth itself illustrates the passage of time? What time scale is illustrated in the example above? How well does this relate to geological time/geological forces? The Good Earth/Chapter 8: Geologic Time Go back to the Table of Contents Go to the next section: The History of (Relative) Time The Good Earth/Chapter 8: Geologic Time The History of (Relative) Time Paradigm shift: 17th century – science was a baby and geology as a discipline did not exist. Today, hypothesis testing method supports a geologic (scientific) age for the earth as opposed to a biblical age. Structures such as the oldest Egyptian pyramids (2650-2150 B.C.) and the Great Wall of China (688 B.C.) fall within a historical timeline that humans can relate to, while geological events may seem to have happened before time existed! The Good Earth/Chapter 8: Geologic Time The History of (Relative) Time • Relative Time = which A came first, second… − Grand Canyon – B excellent model − Which do you think happened first – the The Grand Canyon – rock layers record thousands of millions of years of geologic history. -
Chapter 7: the Age of Earth
Earth and Life History Ancient Carvings These beautiful formations in Paria Canyon, along the boder of Arizona and Utah, were carved by the Paria River about 5.4 million years ago. 40,000–12,000 1875 Years Ago Henry Hancock discovers that a Organisms are trapped tooth more than 23 cm long and in tar pits found at La 9 cm wide may be from a saber- Brea (Los Angeles, tooth cat; realizes the bones at California). La Brea could be ancient. A.D. 1 1750 1800 1850 1900 1795 1896 James Hutton pro- Henri Becquerel dis- poses idea that covers radioactivity of natural processes uranium salts not long forming rock layers after Wilhelm Conrad occur uniformly Roentgen discovers throughout time. the X ray in 1895. 278 (bkgd)Layne Kennedy/CORBIS, (t)Albert Copley/Visuals Unlimited, (b)American Institute of Physics/Emilio Segrè Visual Archives To learn more about geologists and paleontologists and their work, visit ca7.msscience.com. Interactive Time Line To learn more about these events and others, visit ca7.msscience.com. c. 1910–1915 1980 1990 First scientific digs of the La Luis and Walter Alvarez from UC NASA researchers Kevin Pope, Brea Tar Pits are made by Berkeley propose that an asteroid Adriana Ocampo, and Charles scientists from the Univer- crashed into Earth 65 million years Duller, identify a huge crater sity of California; about ago, causing the sudden extinction in the Yucatan, Mexico, that 170,000 fossils found. of dinosaurs and many other living they think is the site of the things. asteroid crash. 1900 1920 1940 1960 1980 2000 2020 1913 1967 November 2002 First numeric time scale of geo- Richard Leakey finds two The National Science Founda- logic ages is proposed by skulls and uses new technol- tion launches a program, sci- Arthur Holmes of Great Britain; ogy to date objects more entists from around the world he used radioactive means to accurately; one is 195,000 will verify dates and class of measure the age of Earth years old, the oldest for a old specimens and analyze (about 4 billion years old).