8th grade Astronomy unit:

Big bang

Scientific theory about how the universe started happened 13.8 Billion years ago.

Big bang: what happened

Universe began as a singularity, this singularity started to expand. not explode

Singularity

An infinitely dense, small, high temperature, and massive point.

What is light:

Light is energy that travels as a wave. It is made of photons. Light is produced by stars.

Photons:

Massless energy packets

Refraction:

Where a wave bounces off of a surface and changes direction.

The normal:

90 degree imaginary perpendicular line off of the reflective surface where the light strikes.

Refraction:

The changing of direction of a wave when it passes from one medium (material) into another medium.

Transparency:

When light can go through an object without distortion.

Absorption:

A process where a material takes in light and converts it into heat.

Speed of light:

300,000km/sec

• Light can travel around the world 7.5 times in a second.

Wavelength:

The distance of one full wave of light. ( distance between peaks of light or crests of light)

Wavelength symbol:

Lambda.

Frequency:

How many times a wave passes a location in one second

Hertz(Hz):

Labels frequency

Energy:

More energy= more waves

Amplitude

The height of a wavelength

Correlations:

White light:

All visible light:

Doppler effect:

The apparent change of a wave due to movement

Blueshift:

A star(object) is moving toward you(the source) (waves will hit them more frequently)

Redshift:

When a star/object moves away from the source( waves will hit it less frequently.)

This diagram is showing:

Redshirt.

The further objects are:

The more redshifted they are, the faster they are moving away.

More shift=

More speed

Everything is:

Moving away from each other.

There isi no _____ to the universe’s expansion

Center

Close galaxies are…

Moving away

Further out galaxies are …

Moving away much faster(we know this because of redshift)

We can’t see some extremely far galaxies because…..

They are moving away faster than the speed of light. The light they are giving off never reaches earth because they are moving away too fast.