1 / 78

ASTRONOMY

ASTRONOMY. The study of celestial objects, space, and the universe Considered one of the oldest disciplines of science 3,000 – 4,000 years old. CELESTIAL MOTION. The path a planet follows around the sun is called an ? ORBIT

jenn
Download Presentation

ASTRONOMY

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. ASTRONOMY • The study of celestial objects, space, and the universe • Considered one of the oldest disciplines of science • 3,000 – 4,000 years old

  2. CELESTIAL MOTION • The path a planet follows around the sun is called an ? ORBIT • The orbital movement of a celestial body around an object is called? REVOLUTION • The spinning or motion of a celestial body around an axis is called? ROTATION

  3. HISTORY • Utilized repeated observations of the night sky with the naked eye • Played a significant role in the development of civilization, used to develop the calendar and understand the seasons

  4. HISTORY • As civilization progressed astronomical observatories were constructed • Led to detailed maps of the night sky and ideas about the motion of the planets, Sun, Moon, and Earth.

  5. ARISTOTLE • Described the universe as a series of spheres containing the planets and Sun rotating around the Earth with the stars fixed against the background • “Motionless Earth” idea based on the philosophical idea that if you feel no motion there is no motion • Constellations did not appear to change position or size, no apparent parallax.

  6. PARALLAX • Is the change in the observed position of an object due to the change in location of the observer. • Planets appeared to move position in the night sky, while stars did not. • Stars too far away for a noticeable change in position with the naked eye

  7. PTOLEMY • 140 A.D., 5 centuries after Aristotle • Developed a mathematical model based on Aristotle’s teachings • Ptolemaic/Geocentric Model

  8. GEOCENTRIC MODEL • Earth is fixed at or near the center of the universe • Planets and the Sun move along a perfect circular path • Planets also follow a circular path, epicycle, that is centered along the circular path around the Earth Abyss.uoregon.edu

  9. COPERNICUS • Challenged the Geocentric Model in the 1500’s • Proposed the Heliocentric Model, planets follow circular paths around the Sun, not the Earth. • Maintained classical concept of uniform circular motion

  10. HELIOCENTRIC MODEL • Recognized as the “Copernicus Revolution”, placing the Earth along a similar orbit to that of the other planets. • Helped explain Retrograde Motion Stisci.edu

  11. RETROGRADE MOTION • When planets seem to move in the opposite direction across the night sky • Occurs because the planets move around the Sun not the Earth • The difference is speed also affects Retrograde Motion but did not fit the classical uniform circular models

  12. Redorbit.com

  13. KEPLER • In the early 1600’s abandoned the classical ideas of the circular and uniform motion of the planets • Studying the motions of Mars discovered the planets move in an ellipse rather than a circle • Noticed that the speed of Mars was not constant, but varied along its’ path

  14. ELLIPSE

  15. KEPLER’S LAWS OF PLANETARY MOTION 1ST LAW Planets orbit the sun along an elliptical path • Ellipse is an oval-like shape drawn around two focus points, foci. The distance from one focus to any point on the ellipse and then back to the other focus is a constant • The closer the foci the more circular the ellipse becomes, most planets are nearly circular

  16. KEPLER’S LAWS OF PLANETARY MOTION • 2nd LAW Planets move faster along their elliptical path the closer they are to the sun

  17. KEPLER’S LAWS OF PLANETARY MOTION 3rd LAW The farther a planet is from the sun, the longer it takes to complete the elliptical orbit • The semi-major axis is the average distance from the planet to the sun

  18. KEPLER’S LAWS • All of the laws are empirical, based on observation and data rather than theoretical • Kepler never knew what held the planets along their orbits or why they continued to revolve around the sun

  19. MODELS • Used to display, represent, and demonstrate the structure and behavior of the Cosmos • Allow scientists to test and observe behaviors on a smaller scale • Models of our Solar System

  20. TOOLS & TECHNOLOGY • Astronomer’s study the light that reaches Earth from distant objects in space • Light is a form of electromagnetic radiation • Electromagnetic Radiation is a form of wave-like energy emitted by the acceleration of a charged particle by a force

  21. ELECTROMAGNETICWAVES • Do not require a medium, can travel in space • Travel at a speed of 300,000 km/s through space, speed of light. • Represents a spectrum of different wavelengths

  22. R O Y G. B I V red orange yellow green blue indigo violet ELECTROMAGNETIC SPECTRUM

  23. TELESCOPES • Used to aid astronomers in the collection of light normally not visible to the naked eye. • collect more light • over a longer period of time • better image from space Popularmechanics.com

  24. SATELITES & PROBES • Atmosphere blocks certain wavelengths of electromagnetic radiation • Why does this matter? Nasa.gov

  25. How do they do it??? Nasa.gov

  26. ORIGIN OF THE UNIVERSE Big BANG Theory • Expansion of a single unstable dense collection of matter and space • Gases, dust, particles and energy exploded outward • Gases and particles cooled/condensed into planets, stars, & galaxies • Matter and space still expanding out from explosion • Red Shift demonstrates present day expansion

  27. RED SHIFT EXPANSION • Light observed from distant galaxies have light shifted toward the red side of the spectrum. • The shift toward “red” is due to an increase in wavelength due to the DOPPLER EFFECT

  28. MILKY WAY GALAXY • “via lactae” latin for Milky Way • “Milky” band appearance created by disk-shape of our galaxy viewed from within • Millions of stars and planets, including our solar system • All orbit the proposed “black-hole” center

  29. Our Solar System • Formed by a Solar Nebula (4.6 bya) • Hot dense center of cloud condenses into the Sun • Disk-like cloud of gases surrounding Sun has various regions of temperature • Different elements cool, condense, and combine in different regions Universetoday.com

  30. THE SUN • Largest object in our solar system • 99% of the mass of our solar system • Large mass = strong gravitational force, resulting in the orbits of all the planets

  31. GRAVITY • Gravitational force is a force of attraction dependent on the mass and distance between two objects. • Described by Sir Issac Newton in 1687 as the Law of Universal Gravitation

  32. THE SUN • The sun’s energy comes from Nuclear Fusion • Nuclear Fusion – small light nuclei (hydrogen atoms) are combined to form larger nuclei (helium atoms) resulting in the release of ENERGY • E = mc2

  33. NUCLEAR FUSION

  34. SUN’S ATMOSPHERE • Photosphere • 6,000 K • Surface, yellow-color • Chromosphere • 30,000 K • Only visible during solar eclipse, reddish • Corona • 1- 2 million K • Only visible during solar eclipse, white • Solar Winds

  35. SOLAR WIND • Originate in the Corona • Stream of charged atoms known as “ions” • Collide with Earth’s magnetic field creating the Auroras. Harvard.edu

  36. Nationalgeographic.com

  37. SOLAR ACTIVITY • Changes in the Sun’s atmosphere • 11 year cycles • Sunspots and Solar Flares • Interfere with phone, TV, and radio reception • Affects climate on Earth Nasa.gov

  38. INNER PLANETS • terrestrial planets • dense, small, have solid rocky surfaces, metal cores

  39. OUTER PLANETS • Jovian Planets • less dense, large, gaseous, thick atmosphere

  40. “My Very Eager Mother Just Served Us Noodles”

  41. EARTH • 3rd planet from the Sun • Nearly circular orbit • Moderately dense atmosphere • 78% Nitrogen 21% Oxygen • Greenhouse Effect • Water • Solid, Liquid, Gas

  42. EARTH’S MOTION • Rotation • Earth rotates around an axis • Night and Day • 24 hours • Revolution • Earth revolves around the Sun, Heliocentrism • Seasons • 365 days = 1 year

  43. EARTH’S ROTATION • Rotates along a tilted axis, 23.5o • Rotates West to East • Mean Solar Day = 24 hours • 15o / hour rotation • The “day” is getting longer due to tidal friction • inertia

  44. Astro.psu.edu

More Related