Earth’s sphere tilts on its axis at an angle of 23.5 degrees; this gives us our seasons, with parts of the planet receiving more direct sunlight in summer than in winter. However, not all solar system planets are tilted like the Earth: Uranus is tilted at 98 degrees, whereas Mercury is not tilted at all. According to new research led by Purdue University, a planet with a tilted axis helps to promote oxygen production by doubling the output of photosynthesis. Exoplanets...
