Exploring the Planets: Intro

Universe

Totality of all space, time and matter

Hypothesis rules

1. must be testable 2. must be repeatable 3. must be falsifiable

Scientific Theory

Explain how/why something happens and can evolve and change over time

Scientific Law

A mathematical equation describing a pattern in nature that remains constant until proven wrong

Sidereal day

1 full rotation relative to distant stars (23h 56m 4s)

The ecliptic

Plane of earth's path around the sun, marked by the path the sun takes across the celestial sphere

Earth's tilt

23.5 degree toward Polaris

Precession

Shift in the tilt of the earth from north to south, takes about 26,000 years

Angular measure

Measuring size in degrees, 1 degree of rotation is 60'(arcminutes) and each arcminute is 60'' (arcseconds) eg moon and sun have the same angular size in our sky

Moon rotation

Moon rotates synchronously with earth so we always see the same side -takes 27.3 days to complete 1 turn around the earth and one turn on its axis

New Moon

Phase 1, moon is not visible from earth

Waxing Crescent

Phase 2, small section of right side is illuminated

First Quarter

Phase 3, right half is illuminated

Waxing Gibbous

Phase 4, only left corner is not illuminated

Full Moon

Phase 5, full face of the moon is illuminated

Waning Gibbous

Phase 6, all except right corner is illuminated

Last Quarter

Phase 7, left half is illuminated

Waning Crescent

Phase 8, left corner is illuminated

Lunar Eclipse

Earth is between the moon and the sun

Solar Eclipse

Moon is between the sun and the earth

Parallax

Measuring distance from earth to an apparent moving object using two "fixed" points of objects very far away (so they don't appear to be moving), measure once, and then again after 6 months