Sunrise Solstice at Stonehenge . ... Credit Copyright: Max Alexander , STFC , SPL Explanation: Today the Sun reaches its northernmost point in planet Earth's sky. Called a solstice , the date traditionally marks a change of seasons -- from spring to summer in Earth 's Northern Hemisphere and from fall to winter in Earth's Southern Hemisphere . ... NASA Web Site Statements, Warnings, and Disclaimers . NASA Official: Jay Norris. ... A service of: LHEA at NASA / GSFC . ...