Topic 1: Formation of the Universe

The Universe

consists of billions of other galaxies

The Universe

houses our galaxy, the Milky Way

The Universe

comprised of energy and matter that physically exists -is approximated to have existed since 14 billion years ago

Brightness and Luminosity

Measurements of the brightness of distant stars

Brightness and Luminosity

Cepheid variables and period of pulsation

Brightness and Luminosity

Used to calculate the distance of Earth from different stars

Brightness and Luminosity

The universe is expanding

The Doppler Effect

Changing frequencies due to the relative motion of a sound source

Observed whenever the source of waves is moving with respect to an observer.

The Doppler Effect

The Doppler Effect

Effect produced by a moving source of waves in which there is an apparent upward shift in frequency for observers towards whom the source is approaching and an apparent downward shift in frequency for observers from whom the source is receding.

A moving ambulance exhibits the:

Doppler Effect

red shift

However, the frequency of the sound is actually NOT changing – it just seems so because it its moving. This is in relation to how the universe is expanding due to the phenomenon known as the ___ ______, which is similar to the concept of the Doppler effect.

red shifts

Astronomers use ___ _____ to measure how the universe is expanding, and thus to determine the distance to our universe’s most distant (and therefore oldest) objects.

Red shifts

Light behaves like a wave, so light from a luminous object undergoes a Doppler-like shift if the source is moving relative to us.

1929

What year did Edwin Hubble discover that the Universe is expanding, we have known that most other galaxies are moving away from us.

red shifted

Light from these galaxies is shifted to longer (and this means redder) wavelengths - in other words, it is…