Erthpsc unit2

planemonsun

copernicus

placed sun in center of system

Brahes

observations especially of Mars accuretly estimated positions of planted and stars allowed for kelpers laws

kepler and his planetary motion

1.) law of orbit-not circular elliptical

2. Law of areas- a line segment joining a planet and the sun sweeps out equal areas during equal intervals of time.

3. law of period- the square of the orbital period of a planet is directly proportional to the cube of the semi-major axis of its orbit.

galileo

• Moons of Jupiter: Discovered four moons orbiting Jupiter, proving Earth is not the center of all celestial motion.

• Phases of Venus: Observed Venus tracking a full cycle of phases, proving it orbits the Sun.

• Sunspots: Tracked dark spots on the Sun, showing it is imperfect and rotates on an axis.

• Lunar Topography: Revealed the Moon has mountains and craters, proving it is a rocky world like Earth.

• Milky Way Stars: Resolved the galaxy's cloudy glow into millions of individual stars, showing a much larger universe.

• Saturn's "Ears": Made the first telescopic observations of Saturn, noting strange lateral bulges that were later identified as rings.

newton

law of gravitation

aristarchus

first proposed sun was center

one astronomical unit

150million kilometers

14,000 years earths northern rotational axis will point to

Vega due to prescetion earths wobble

hiparchus

1. Discovering the Precession of the Equinoxes

2.Creating the First Star Catalog- It mapped the celestial coordinates (latitude and longitude) and brightness magnitudes

3.He used these early trigonometric calculate the distances to the sun and moon

erastothenes how he measured earth

by measuring the sun's shadow angle in Alexandria while it was directly overhead in Syene. Because the shadow angle was 7.2 degrees (1/50th of a circle), he multiplied the distance between the two cities by 50 to estimate a total circumference of roughly 40,000 kilometers, which is incredibly close to modern measurements.

newtons orbit

• Gravity: This is the attractive force between the Sun and the planet. It pulls the planet inward, preventing it from drifting off into space.

• Inertia: This is the tendency of an object in motion to stay in motion in a straight line. The planet's forward speed tries to carry it straight out into the void

moons slow rotation on surface

• Extreme Temperatures: A single day lasts two Earth weeks, causing temperatures to soar to 260°F (127°C), followed by a two-week night where they plunge to -280°F (-173°C).

• Permanent Shadows: Because of the slow, upright spin, deep craters at the lunar poles never see sunlight, creating permanent deep-freezes that trap water ice.

• Asymmetric Crusts: Tidal locking permanently hides the far side from Earth, where a thicker crust prevented the formation of the large, dark volcanic plains (maria) seen on the near side.