Ch. 14.1 (The Night Sky)

Question 1

Point sources of light

Answer 1

• Light from stars, planets must pass Earth’s atmosphere to reach you. This factor affects the light.

Question 2

Twinkling

Answer 2

• Stars twinkle because density differences in atmosphere refract the point of starlight one way, then the other as air moves
• The slight dancing and changes in intensity is called twinkling.
• Stars do not twinkle outside atmosphere, appear as steady point sources.

Question 3

Light-year

Answer 3

• A unit of astronomical distance that uses time.

- The distance that light travels in one year (about 9.5 x 10^12 km)

Question 4

Celestial sphere

Answer 4

• Established by imagining the sky as a celestial sphere.
• Coordinate system of lines can be visualized just as one thinks of the latitude-longitude system on Earth’s surface.
• Sky coordinates can be created by picturing latitude and longitude lines to sphere.
• Can only see one-half of overall sphere from any one place on Earth’s surface.

Question 5

Celestial equator

Answer 5

• The line of the equator on the celestial sphere.

Question 6

North/south celestial pole

Answer 6

• Where the North/South Pole of Earth touches the celestial sphere. Are directly above respective poles.

Question 7

Celestial meridian

Answer 7

• An imaginary line in the sky directly above you that runs north through the n. celestial pole, south through the s. celestial pole and back around the other side of to make a big circle around Earth.
• It’s location is determined by where you are on Earth. The celestial poles and equator’s positions stay the same.

Question 8

Altitude and azimuth angle

Answer 8

Altitude: Identified by going from the horizon up to an object in celestial sphere.

Azimuth: Identified by going east or west of due south, where celestial meridian meets horizon.