An Introduction to the Universe

An Introduction to the Universe

And a few numbers and simple mathematical techniques for developing a sense of scale.

Let’s start at the planet we call home

Earth

The first lesson in scale….How many Earth’s would fit side by side between

the Earth and the Moon?

Image from the Mars Express Spacecraft

Lest we forget…

The Universe has a history of

violence.

The earliest astronomical

models placed the Earth at

the center of a celestial giant

sphere.

Just 500 years ago, during the Renaissance, philosophers began to re-examine our place in the Universe.

The Sun is now considered to the be the center of our solar system

This image of Saturn backlit by the Sun taken by the Cassini Spacecraft partially illustrates our position in the Universe

Stars are now believed to form in clusters like this one (M45) that still is surrounded

by some of the gas and dust that stars form from.

With the invention of the astronomical telescope in the early 1600’s, astronomers were able to see

previously unknown objects like this Globular Cluster of stars in the constellation called M13

Galaxies are distributed in clusters

Other galaxies are grouped in rich clusters that may contain upward of 50,000

galaxies.

Abell 1689

The Hubble telescope reveals the tru character of rich galaxy cluster Abell 1689

Our own galaxy is believed to be similar in structure to this galaxy called the Whirlpool Galaxy (M58)

Note the two supernova

Our own Milky Way Galaxy is part of a poor galaxy cluster called the Local Group.

This map of small variations in the Cosmic Background Radiation has allowed

astronomers to pin down the age of the Universe as 13.78 Byr

Evidence for Dark Matter was firmly established by Vera Rubin by measuring the rotation speeds of stars in

distant spiral galaxies

Our understanding of the beginnings of our Universe has given rise to a phenomena known as cosmic

inflation that explains the current large scale structure of our Universe.

Recent measurements of supernova in distance galaxies has provided evidence that there is an unknown energy that is causing our Universe to

accelerate its expansion – Dark Energy