Earth Science Astronomy #2 PDF
Document Details
Uploaded by Deleted User
Tags
Summary
This is an Earth science document focusing on basic astronomy concepts, such as the Solar System, planetary rotation, and basic planetary characteristics and their chemical differentiation into terrestrial and Jovian types. It provides various data sets for planets like Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune.
Full Transcript
The Planets & the New Solar System olar System -a system of planets, asteroids, meteors,satellites (i.e. moons) and comets that are S “captured” in orbit around a central Star or stars. -Smaller part of a galaxy Age of Our Solar System- 4.568 billion years old (4.6is fine too fo...
The Planets & the New Solar System olar System -a system of planets, asteroids, meteors,satellites (i.e. moons) and comets that are S “captured” in orbit around a central Star or stars. -Smaller part of a galaxy Age of Our Solar System- 4.568 billion years old (4.6is fine too for regents exam) Formation SS - Nebular Hypothesis Jean’s instability/Jean’s mass and length. When a nebular cloud contains a certain amount of debris (mass) and has reached a certain size (diameter), the likelihood of cloud contraction is high. Gravitational collapse of a small part of a giant molecular cloud (sweeping/accretion) C loud of dust rotating → causes areas to circulate → circulation = sweeping Smaller region circulation - particles bump and stick together (causesstatic- which is a force) Mineral greens are charged They clump together because ofSTATIC! Formation : Nebular Hypothesis Sweeping Gathering of surrounding debris by rotational forces Accretion Initially small particles of gas and dust stick together via their electrostatic attraction. As they grew larger, their gravity became strong enough to attract particles as well and their growth accelerated. Once large enough, gravity pulls the planetesimal into a spherical shape. 1 Chemical Differentiation 1. A process in whichheavyelements sink towards thecenter of an object while the lighter elements remain closer to the surface. 2. This is the reason that internal structures of planets are dense, rocky, and heavy, 3. Solar wind blows out the reaminging Nebular Gases which helped form the large gaseous atmospheres of the Jovian Planets. 1. Terrestrial Planets a. “Earth Like” b. Inner 4 most planets c. Bodies of mostly rock General Characteristics ○ Small radii, low mass, high density ○ None to thin atmospheres ○ Craters, canyons, and volcanoes ○ Mercury, Venus, Earth, Mars Specific Planet Data: 1.Mercury: a. Closest planet to sun b. 2nd hottest planet ---- ~-1800c to 4300c c. No atmosphere/ No Greenhouse effect d. Smallest e. No satellites 2.Venus: a. 2nd from sun b. Hottest Planet!!!!!!!!! c. Thick Atmosphere of CO2/ Large greenhouse effect. d. Temps: ~4650c to -1750 c 3.Earth: a. See Geology Unit b. Only known to have life!!!!! c. Only planet to have Vast amounts of Liquid water 4.Mars: a. Red planet – Has high amounts of Fe b. Largest Volcano in S.S. Olympus Mons c. Geologically active d. Thin Atmosphere of CO2 e. Similar temps and seasons to that of Earth f. Frozen Water at its poles 2 Planetary Rotation- Mercury-.1 degrees Venus- 177 degrees Earth- 23.5 degrees Mars- 25 degrees Asteroid Belt- separates the Terrestrial from theJovian planets 2. Jovian Planets a. “Jupiter Like” b. Outer 4 most planets c. Gas giants General Characteristics ○ Large radii, high mass, and very low density ○ Composed of primarily gases (Thick Atmosphere) H2 and He some CH4 ○ Solid Cores of the planets are believed to exist deep under the gases. ○ All have ring systems Specific Planet Data: 5.Jupiter: ○ 92% Gas (Hydrogen & Helium) ○ Great Red spot (~300yrs) ○ Total mass twice that of all other planets. 6.Saturn: ○ Has rings ~150 km thick. (Made from Rock and Ice) ○ 930 mi/hr winds. (Strongest) ○ Less dense than Water (.7) 7.Uranus: ○ Mostly Methane Gas gives it a Blue-green color. ○ Very strange Rotation. It rotates tilted 98° on its side. 8.Neptune: ○ Great blue spot 3 Planetary Rotation- Jupiter- 3 degrees Saturn- 27 degrees Uranus- 98 degrees Neptune- 30 degrees The Great & Powerful Astronomers 1. Aristotle- Greek Philosopher (384-322 BC) a. Father of Science b. Student of Plato ○ Aristotle disagreed with the four elements of other Greek Philosophers. ○ He believed that the 4 elements were hot, dry, wet, and cold, which could then combine to form the elements earth, air, water, and fire. ○ Introduced the idea of an earth centered model of our solar system but could not explain it. 2. Ptolemy- Greek/Egyptian (85-165 AD) a. Enhanced the Geocentric Model of the SS (Ptolemaic Model). b. Used Epicycles to explain retrograde motion (minor orbits) c. Model was accepted for ~1,400 years. Retrograde Motion (Reverse motion) ○ An apparent change in the movement of a planet through the sky, caused by Earth passing slower- moving outer planets. ○ The wandering backwards of an object As viewed from Earth, Mars moves east across the sky each day. (~ every 26 months) Mars appears to slow down, stop and move in the opposite direction. (West) This process takes approximately 4 months ○ Retrograde is partly the result of: PARALLAX Anapparentchange in the direction of an object,caused by a change in observational position that provides a new line of sight. 4 “Geo” Centric Model Planetary Models Diagram 1. Geocentric Model- a. “Earth Centered” Greeks believed the Earth was the center of the universe. b. Was the belief of the Catholic Church. Anyone who did not believe could be put to DEATH! 3. Tycho Brahe- Danish (1546-1601) a. What did he do? ○ Designed and built astronomical instruments. ○ (Sextants and Quadrants) ○ Accurately append the night sky. ○ Observed planetary bodies throughout their orbits. ○ Tychonic Model of SS ○ Observed (naked eye) the SN 1572 supernova on November 11th 1572 ○ Established and built te Uraniborg, an early astronomical institute (Hven) b. Tychonic Solar System ○ Gained a considerable following after Rome declared that the heliocentric model was contrary to Scripture, and could only be discussed as a computational convenience they had no connection or fact. 4. Nicholas Copernicus- Polish (1473-1543) a. Developed the Heliocentric Model b. Wrote “De Revolutionibus Orbium Coelestium” ~1514 c. Thought the planet’s orbits formed perfect circles around the Sun. 5. Galileo Galilei- Italian (1564-1642) a. Father of Modern Science!! b. Invented different science equipment & vastly improved the telescope. c. Discovered 4 moons of Jupiter d. Defended heliocentric but forced to recant and live in house arrest. 5 “Helio” Centric Model Planetary Models Diagram 2. Heliocentric Model- a. “Sun Centered” b. Explained how the sun was the center of the universe. c. Planets orbits were circular. d. Copernicus released findings on his deathbed 6. Johannes Kepler- German (1571-1631) a. Father of Planetary Motions b. Proposed 3 laws of Orbital Motion c. Made the Heliocentric model more accurate epler’s Laws of Motion K There are 2 major motions of the Earth… . R 1 otation- spinning of the earth on its axis 2. Revolution- the movement of the Earth in orbit around the sun recession- a minor change in the orientation of theaxis of rotation within arotatingbody. P Ex: a top H ipparchusproposed that the axis around which theheavens seemed to rotate (shifted) gradually. Earth’sequatorial bulgeand lunar wandering causedthe Earth’s precession The rate of one full cycle is:~26,000 yearsor ~1degree per 72 years epler’s Laws of Planetary Motion K Developed during the 1600’s 🔽 6 . L 1 aw of Ellipses 2. Law of Equal Areas 3. Harmonic Law Law #1 Kepler stated that: ○ Allsatellites(planets) orbit the sun in ellipses. ○ An ellipse looks like a flattened circle which can be drawn using 2 points as opposed to one center point for a circle. Eccentricity Basics Eccentricity is calculated by dividing the distance between the foci by the length of the major axis. E ccentricity can range from: 0 (circle) to 1 (line) ex:.305 No planetary object can be 0 or 1- ONLY a decimal between them The Earth’s Orbit A single orbit around the Sun takes how many days for Earth?365.26 The Sun is at one focus of the Earth’s orbit(nothing at the other) The Earth’s eccentricity according to the ESRT is?? - 0.017.. Almost a circle!! 7 erihelion- the point on its orbit when the Earth isclosestto the Sun. P Aphelion- the point on Earth’s orbit when it isfarthestfrom the Sun. The Sun viewed from Earth at perihelion V. Aphelion Apparent Angular Diameter Elliptical Orbital Motion(not to scale) Orbital Velocity 8 Kepler’s Laws Continued… Law #2 Law of Equal Areas ○ States that an imaginary line joining to the Sun will sweep overequal areas(“space between”) inequal time. One short/wide triangle is the sameareaas a longerthinner triangle. Law #3 Harmonic Law ○ States that: A planet’s period of revolution (it’s year) depends on its distance from the Sun. ○ The farther from the sun, the larger, longer, and slower its planetary orbit. ○ Math: If: the orbital period of an object is known (P = how long it takes the planet to go around the sun) Then: the planet’s distance from the Sun in Au’s can be determined. (r or A = mean distance) P ○ 2 is proportional to r3 ○ P2 = r3 P ○ = period of revolution of revolution (yrs). ○ R = Avg distance between planet and the Sun in AUS. ○ AU = 149.6 (150) million kilometers Astronomrs THE END! 9
