Dark Energy

The universe is expanding. We have known this for many years. Now, however, we know that the expansion is speeding up! Why? There must be some kind of energy at play. We don't know much about it yet, so we call it Dark Energy.

What was before the Big Bang?

According to the theory of inflation, the early Universe expanded exponentially fast for a fraction of a second after the Big Bang. Cosmologists introduced this idea in 1981 to solve several important problems in cosmology. http://www.ctc.cam.ac.uk/outreach/origins/inflation_zero.php

How Does Inflation Work?

Inflation is the idea that there was something in existence just before the Big Bang. The basic idea behind inflation is that a repulsive form of gravity caused the universe to expand.
Explore this for more.

The Hubble Deep Field Images

Several hundred never before seen galaxies are visible in this "deepest-ever" view of the universe, called the Hubble Deep Field (HDF), made with NASA's Hubble Space Telescope. Besides the classical spiral and elliptical shaped galaxies, there is a bewildering variety of other galaxy shapes and colors that are important clues to understanding the evolution of the universe. Some of the galaxies may have formed less that one billion years after the Big Bang.

This short film summarizes the Deep Field's discoveries.

Cosmic Calendar

If the 13.7 billion year history of the universe was compressed into one year, what would the calendar look like? At this scale the Big Bang takes place on January 1 at midnight, the current time is December 31 at midnight, and each second is 434 years.
Let's find out ...

Astronomy Reading List

Deepen your knowledge of Astronomy and have some fun. These fiction and non-fiction works are organized according to units in the course. Let me know if you want to substitute an essay or book review for an assignment in the course.

3-D Model of the Milky Way Galaxy

This experiment by Google accurately models 100,000 stars in our galaxy.
You can click on individual stars to learn more about each one.
100,000 Stars