Astronomy - Forces and Solar System

Orbit

The path that a body follows as it travels around another body in space

Revolution

The motion of a body that travels around another body in space; one complete trip along an orbit.

Earth's Orbital Period

The Earth revolves around the Sun once every year.

Rotation

The spin of a celestial body on its axis.

Earth's Rotational period

The Earth rotates on its axis once every 24 hours causing day/night cycle

Mass

A measure of the amount of matter in an object.

Weight

A measurement that tells how much the gravitational force pulls down towards the center of an object.

Is your mass same in every planet?

Yes, you still have same amount of matter everywhere.

Is your weight same in every planet?

No, planets have different masses so their gravitational forces are different.

Moon has less gravity than Earth. What would your mass be in moon compared to your mass in Earth?

It would be the Same (mass does not change, the weight does).

Moon has less gravity than Earth. What would your weight be in moon compared to your weight in Earth?

It would be less because weight measures how much gravity is pulling on the object.

Comet

These are celestial bodies nicknamed "dirty snowballs" composed of dust and rock mixed with frozen water, methane, and ammonia. Each travels an elliptical path around the sun.

Meteoroid

A small body moving in the solar system that would become a meteor if it entered the earth's atmosphere.

Meteor

A streak of light in the sky produced by the burning of a meteoroid in Earth's atmosphere. Known as a "shooting star".

Meteorite

A piece of space rock that passes through the atmosphere and strikes Earth's surface.

Inner Planets (Mercury, Venus, Earth and Mars)

These planets are nicknamed "Terrestrial" meaning (rocky). These planets are small, dense, and have few moons.

Outer Planets (Jupiter, Saturn, Uranus, & Neptune)

These planets are nicknamed Gas Giants. Each gas giant is gaseous, large, less dense, and rings.

Spiral

What is the type (shape) of Milky Way galaxy?

What keeps the planets orbiting the Sun in their elliptical paths?

The gravitational force between the planets and the Sun and Inertia what keeps them moving forward.

My Very Excellent Mother Just Served Us Nachos

Tell a mnemonic to remember the planets in order

Gravity

A force that pulls objects toward each other. Mass and distance determine the strength of this force.

Inertia

The tendency of an object to resist a change in motion. An object at rest stays at rest unless acted upon by an external force.

Newton's 1st Law

An object at rest stays at rest and an object in motion stays in motion with the same speed and in the same direction unless acted upon by an unbalanced force.

Law of Universal Gravity

Every object in the universe attracts every other object

Natural Satellite

A naturally occurring object that stays in orbit around a planet.

Cosmic Address

The structure of the Universe from smallest to largest: Earth, solar system, Milky Way Galaxy, Local Group, Local Supercluster, Universe.

Orion's Arm

This is where our Solar system is located in the Milky Way which is not in the center.

Universe

Space and all the matter and energy in it like galaxies, stars, planets, and all phenomena that exist.

Galaxy

A huge group of stars, star systems, star clusters, dust, and gas bound together by gravity.