The SUN

   The Sun is located on the inner edge of a spiral arm. The center, or nucleus, of the galaxy is about 27,000 light-years distant, in the direction of the constellation Sagittarius.

   Earth speed: 29,78  km/s

   Solar System speed: 220 km/s

   Milky Way speed relative to CMB rest frame:        552 km/s [Cosmic microwave background radiation]

   All the stars in the galaxy move in orbits around its center. The Sun takes about 225-250 million years to complete an orbit. The orbits of most of these stars are nearly circular and are nearly in the same direction.

   The distance between the Sun and Earth is roughly 93 million miles (150 million kilometers, 1 AU).

Light travels through space at about 186,282 miles (299,792 kilometers) per second, so a ray of sunlight takes only about 8 minutes to reach Earth. Light from other stars takes much longer to reach Earth; light from the next nearest star, Proxima Centauri, takes more than four years to arrive.

   Whitish blue stars have very high surface temperatures (more than 30,000 Kelvin) and red stars are relatively cool  (less than 3,500 K). (The Kelvin temperature scale uses degrees of the same size as Celsius, or centigrade, degrees, but it is numbered from absolute zero, −273.15° C.)

   The Sun is a yellow dwarf star, a kind that is common in the Milky Way galaxy. It has a surface temperature of about 5,800 K. Its diameter is about 864,950 miles (1,392,000 kilometers), which is about 109 times the diameter of Earth. Its volume is about 1,300,000 times Earth’s volume, and its mass, or quantity of matter, is some 333,000 times as great as Earth’s mass. More than 90 percent of the Sun’s atoms are hydrogen. Most of the rest are helium, with much smaller amounts of heavier elements such as carbon, nitrogen, oxygen, magnesium, silicon, and iron. By mass, the Sun is about 71 percent hydrogen and 28 percent helium.

    A white object, as distinguished from white light, is white because when white light falls upon it, it reflects all those zillions of colors back to our eyes equally, without changing the composition of the mixture at all. Its molecules just don't happen to be absorbers of visible light, so it appears to be the same “color” as the light that fell upon it: what we choose to call “white.” The object contributes no color of its own. But colored objects are indeed contributing colors of their own. Their molecules are selectively absorbing and retaining certain of the sunlight's colors, reflecting back the others as an altered mixture. So if an object is black it means it absorbs all light (all colors) and this generates heat. Ex: a blue material isn't blue because the atoms on the surface have the color blue but because they absorb the red, yellow, green, colors and reflect the blue that we can see with our eyes.