You can probably imagine an early universe without planets or stars — but what did the universe look like before time existed? This fall, you could find out by taking a free class led by prominent ...

How can we use light to learn about the universe? How can we measure the properties of planets, stars, and galaxies? How can we explore our cosmic origins and the history of the universe? This course ...

An interest in astronomy may strike early in life or later. Regardless of what lit the fire of that interest, you need knowledge to help you understand the universe. Some of the most important sources ...