Solar System their mass, orbit, and distance from the Sun, with a possibly significant contribution from comets. The Sun, which comprises nearly all the matter in the Solar System, is composed of roughly 98% hydrogen and helium. Jupiter and Saturn, which comprise nearly all the remaining matter, are also primarily composed of hydrogen and helium. A composition gradient exists in the Solar System, created by heat and light pressure from the Sun; those objects closer to the Sun, which are more affected by heat and light pressure, are composed of elements with high melting points. Objects farther from the Sun are composed
Solar cycle 24 to trigger a radio blackout. Larger than the planet Jupiter, the AR 12192 sunspot was visible during a partial solar eclipse seen in North America. The sun emitted a mid-level solar flare, an M7.9-class, peaking at 4:16 a.m. EDT on June 25, 2015. In early November 2015, solar flares disrupted the air traffic control system in central and southern Sweden, causing heavy delays for passengers. A sunspot group originally attributed to the new solar cycle 25 is observed. The sunspot numbers continue to decline. During 2016, there were 26 days with no sunspots (preliminary numbers). As of 31 March, preliminary