Purple Earth Hypothesis suggests Earth was once a purple planet. Early microbes used retinal, not chlorophyll, for ...

Mars, Venus, Jupiter and Saturn should be visible to the naked eye, but with a telescope you can spot Neptune and Uranus.

Ever noticed how the sky turns a strange greenish hue before a tornado? This eerie phenomenon has baffled people for years, but science finally explains why it happens! The color shift is caused by ...