6th grade Astronomy Chapter 1 Flashcards
Newton’s First Law of Motion
An object at rest will stay at rest and an object in motion will stay in motion with a constant speed and direction unless acted on by a force
Inertia
The tendency of an object to resist a change in motion
Force
A push or pull exerted on an object
Law of Universal Gravitation
Every object in the universe attracts every other object
Weight
The force of gravity on an object
Mass
The amount of matter in an object
Gravity
The attractive fore between objects;
it’s strength depends on their masses and the distance between them
Rotation
The spinning motion of a planet on its axis
Revolution
The movement of an object around another object
Orbit
The path of an object as it revolves around another object in space
Axis
An imaginary line that passes through Earth’s center and the North and South poles, about which the Earth rotates. 23.5 degrees
Solstice
The 2 days of the year on which the sun reaches its greatest distance north or south of the equator.
Equinox
- The 2 days of the year on which neither hemisphere is tilted toward or away from the sun
- Means “equal night”- each are about 12 hrs. long
- Halfway between the solstices
Calendar
A system of organizing time that defines the beginning, length, and division of a year
Phases
One of the different shapes of the moon as seen from Earth
Lunar Eclipse
The blocking of sunlight to the moon that occurs when Earth is directly between the sun and the moon.
Solar Eclipse
The blocking of sunlight to Earth that occurs when the moon is directly between the sun and Earth.
(NEW MOON)
Eclipse
The partial or total blocking of one object in space by another
Umbra
The very darkest part of the moon’s shadow
From any part in the Umbra, light from the sun is completely blocked by the moon
Penumbra
The part of a shadow surrounding the darkest part
The larger part of the shadow in which part of the sun is visible from Earth
Tide
The periodic rise and fall of the level of water in the ocean about every 12.5 hours
Caused mainly by the differences in how much the moon’s gravity pulls on different parts of Earth
Neap Tide
A tide with the least difference between consecutive low and high tides
When the sun is at right angles to the line between earth & moon
Spring Tide
The tide with the greatest difference between consecutive low and high tides
When the sun, moon, and Earth line up.
Astronomy
The study of the moon, stars, and other objects in space
Earths Circumference a the equator
25,000 miles. It takes 24 hours to rotate, once
Jean Leon Foucault
French physicist. Proved in the mid-1800’s that the Earth rotates
How long for Earth to make 1 revolution around the sun?
The glaxy?
1 year around the sun.
200,000 years around the galaxy
Light year
The distance light travels in 1 year
186,400 miles/sec.
Our nearest neighboring solar system
4.3 light-years away
The farthest object in the known universe
12 billion light years away
A flashing quasar
Ellipse
a slightly elongated circle
