APOD
Astronomy Picture of the Day
Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.
Galileo Demonstrates the Telescope
Explanation: Galileo Galilei made a good discovery great. Upon hearing at age 40 that a Dutch optician had invented a glass that made distant objects appear larger, Galileo crafted his own telescope and turned it toward the sky . Galileo quickly discovered that our Moon had craters , that Jupiter had its own moons , that the Sun has spots , and that Venus has phases like our Moon . Galileo , who lived from 1564 to 1642, made many more discoveries. Galileo claimed that his observations only made sense if all the planets revolved around the Sun , as championed by Aristarchus and Copernicus , not the Earth , as was commonly believed then. The powerful Inquisition made Galileo publicly recant this conclusion , but today we know he was correct.
| Date | October 14, 2001 |
|---|---|
| Credit | Credit: Original portrait by Justus Sustermans painted in 1636. |
| Authors & editors: | Robert Nemiroff (MTU) & Jerry Bonnell (UMCP) |
| A service of: |
ASD at NASA / GSFC, NASA Science Activation & Michigan Tech. U. |



