Astronomy: Solar System Final Review

Astronomy: Solar System Final Review

S0.1 Explain why the night sky changes over the course of a year

·  Sun ‘moves’ through 12 constellations of the zodiac throughout the year

S0.2 Describe the relationship between the tilt of the Earth’s rotational axis and the seasons we experience

·  Tilt leads to more direct sunlight and longer daylight hours

·  Distance is NOT a factor

S0.3 Explain & predict the phases of the Moon

·  Half of the moon’s surface is ALWAYS lit

·  We only see 1 side of the Moon, it’s just not always lit

S0.4 Describe the cause of both solar & lunar eclipses

·  Moon’s orbit is tilted 5o with respect to Earth/Sun orbit

·  Solar happens during New Moon, Lunar happens during Full Moon

S0.5 Use various techniques (triangulation, angular measurement, parallax) to estimate distance to faraway objects

·  Nearby stars/objects appear to move in relation to background stars

S1.1 Describe how visual observations justify our understanding of orbital mechanics

·  Some planets appear to move backwards in the sky (retrograde motion)

S1.2 Explain why planetary orbits must be elliptical

·  Gravity & equal/opposite forces mean both objects orbit

S1.3 Describe how orbital velocity varies from aphelion to perihelion

·  Cover more/less distance in the same time, so speed changes

S1.4 Describe how P2 ~ a3 is used to verify planetary orbits

·  Doubling the period (P) leads to an 8x increase (23) in the radius (a)

S1.5 Use Newton’s Law of Universal Gravitation to predict how the gravitational force changes under the influence of certain variables

·  Gravitational force is directly proportional to the mass of BOTH objects and dependent on the inverse square of the distance between them

S2.1 Identify and describe basic wave properties such as frequency, wavelength, amplitude, and speed

·  Frequency is waves/second (Hz)

·  Frequency * wavelength = speed

·  Amplitude is “height” of a wave

S2.2 Compare different forms of electromagnetic radiation through qualities such as frequency, wavelength, and energy

·  Gamma rays have the highest frequency & energy, shortest wavelength, radio waves are the other end of the spectrum

·  All EM waves have the same speed (speed of light)

S2.4 Use the Doppler Effect to qualitatively determine the relative speed of an object

·  Waves ‘shrink’ moving toward observer (Blueshift) and expand when moving away (redshift)

·  No Doppler shift when movement is lateral (not toward or away from observer)

S3.1 Describe the basic process of how telescopes gather and focus light

·  Reflecting telescopes use mirrors, refracting telescopes use lenses

S3.3 Relate the physical size of a telescope to its ability to gather (sensitivity) and focus light (resolution)

·  Sensitivity is based on area of collecting mirror/lens

·  Resolution is based on diameter and wavelength of incoming light

S3.5 Explain why astronomers use a variety of telescopes to see different portions of the EM spectrum

·  Only radio & visible can completely penetrate Earth’s atmosphere

·  Atmosphere is completely opaque to X-ray & Gamma ray

·  Atmosphere is partially transparent to IR & UV

S4.1 Describe the leading theory for formation of the solar system (nebular theory)

·  Nebular cloud shrunk, spun, flattened into disk and created planets

·  Heaviest materials “sunk” toward center and formed rocky planets

S4.2 Distinguish between asteroids, meteoroids, meteorites, and meteors

·  Asteroid/meteoroid = out in space

·  Meteor = in atmosphere

·  Meteorite = on surface

S4.3 Describe the major properties of comets (origin, composition, orbital characteristics, etc.)

·  Dirty snowballs

·  Short period < 200 years, Kuiper Belt

·  Long period > 200 years, Oort Cloud

S4.4 Summarize current techniques astronomers use to identify extra solar planets (outside our solar system)

·  Exoplanets change the radial velocity of their parent star, detectable via Doppler shift

·  Exoplanets can also eclipse (transit) their star, blocking the light we receive

S5.1 Explain the source of the tides experienced on Earth

·  Sun & Moon both contribute to tidal forces, but Moon is more important due to proximity

·  Tides cycle 2x per day

·  Spring & Neap tides occur on a bimonthly basis

S5.2 Describe the interior of the Earth with a focus on how geologists have arrived at their current theory

·  Earth has a layered interior, confirmed by seismic wave data

·  Earth’s surface is constantly being recycled

S5.3 Explain the role of atmosphere in shaping surface features on the Earth & Moon

·  Our atmosphere shields us from debris and provides a home for weather that leads to erosion of surface features

·  Moon has no atmosphere, so it’s surface is changed only by asteroid impacts