Learn / Ideas that run through all of it
How we found out
One of the ideas that runs through every place the lessons go. 2 lessons, in the order to read them.
Start hereFrom a still Earth to a moving oneFor two thousand years almost everyone was sure the Earth stood still in the middle of everything. Five people, a telescope and one stubborn planet changed that.First look · How it works
Finding the size of everythingNobody can stretch a tape to the stars. The size of the universe was found one step at a time, over two thousand years, and every step made it far bigger.First look · How it works
Outline Still to be written here
- The people who changed the pictureThe astronomers behind the biggest changes in what we know.
- Finding NeptuneThe planet found by sums before anyone saw it.
- How old is the Earth?How the age of the Earth and the Sun was worked out.
- The debate about galaxiesHow astronomers settled whether the spiral nebulae were other galaxies.