A、It’s a well-known fact. B、It’s a common assumption. C、It’s an unfounded theory. D、It’s a scientific belief. D

Our sun is exactly an orange, dwarf star. Although it is not nearly the hottest star known, the surface temperature is about 10,000°F, and that of its interior is thought to be in the range of 20,000,000°F. We commonly think of the sun as burning; yet it is too hot to burn and is composed of elemental gases.
    The sun is more than 865,000 miles in diameter and has a mass one third of a million times greater than the earth’s.Scientists believe that it is two billion years old and, instead of cooling, is still getting hotter. Perhaps, within next two billion years, it will reach a temperature of sufficient intensity to destroy the earth.
    The sun’s halo is almost as hot as its interior. Its tongues of fire leap outward a half-million miles from the sun’s surface at speeds reaching 250,000 miles an hour. Fortunately these tongues do not travel at their full speeds to earth ,nor are their terrific temperatures transmitted through space. Some of the energy from these disturbances does reach our atmosphere ,however, and is believed to changes in weather.