Celebrate Earth Day with Free Printable Posters. Earth Day is a time to appreciate and protect our planet. One easy way to spread awareness is by using printable Earth Day posters.These free ...

Other posters are simpler still – a planet and nothing else – while another charts the geological timescale of Earth over 4.6 billion years, including every eon and age in a way that is ...

The second poster shows Kepler 16b, a planet that orbits twin suns. The third depicts HD 40307g, a so-called Super Earth about 1.4 times the size of our home planet and eight times as massive.