CHARACTERISTICS OF SUN MOON AND THE STARS
The sun, moon and vast array of stars littering the night sky were all essential in generating life on Earth.
SUN
The Sun is by far the largest object in the solar system. It contains more than 99.8% of the total mass of the Solar System
The Sun is, at present, about 70% hydrogen and 28% helium by mass everything else ("metals") amounts to less than 2%. This changes slowly over time as the Sun converts hydrogen to helium in its core.
The outer layers of the Sun exhibit differential rotation: at the equator the surface rotates once every 25.4 days; near the poles it's as much as 36 days. This odd behavior is due to the fact that the Sun is not a solid body like the Earth. Similar effects are seen in the gas planets. The differential rotation extends considerably down into the interior of the Sun but the core of the Sun rotates as a solid body.
The outer layers of the Sun exhibit differential rotation: at the equator the surface rotates once every 25.4 days; near the poles it's as much as 36 days. This odd behavior is due to the fact that the Sun is not a solid body like the Earth. Similar effects are seen in the gas planets. The differential rotation extends considerably down into the interior of the Sun but the core of the Sun rotates as a solid body.
MOON
The Moon is an astronomical body that orbits planet Earth and is Earth's only permanent natural satellite.
From anyplace on Earth, the clearest thing in the night sky is usually the moon, Earth's only natural satellite and the nearest celestial object (240,250 miles or 384,400 km away). Ancient cultures revered the moon. It represented gods and goddesses in various mythologies -- the ancient Greeks called it "Artemis" and "Selene," while the Romans referred to it as "Luna."
When early astronomers looked at the moon, they saw dark spots that they believed were seas (maria) and lighter regions that they believed was land (terrae). Aristotle's view, which was the accepted theory at the time, was that the moon was a perfect sphere and that the Earth was the center of the universe. When Galileo looked at the moon with a telescope, he saw a different image -- a rugged terrain of mountains and craters. He saw how its appearance changed during the month and how the mountains cast shadows that allowed him to calculate their height. Galileo concluded that the moon was much like Earth in that it had mountains, valleys and plains. His observations ultimately contributed to the rejection of Aristotle's ideas and the Earth-centered universe model.
When early astronomers looked at the moon, they saw dark spots that they believed were seas (maria) and lighter regions that they believed was land (terrae). Aristotle's view, which was the accepted theory at the time, was that the moon was a perfect sphere and that the Earth was the center of the universe. When Galileo looked at the moon with a telescope, he saw a different image -- a rugged terrain of mountains and craters. He saw how its appearance changed during the month and how the mountains cast shadows that allowed him to calculate their height. Galileo concluded that the moon was much like Earth in that it had mountains, valleys and plains. His observations ultimately contributed to the rejection of Aristotle's ideas and the Earth-centered universe model.
STARS
A star is type of astronomical object consisting of a luminous spheroid of plasma held together by its own gravity. The nearest star to Earth is the Sun.
STARS ARE COSMIC energy engines that produce heat, light, ultraviolet rays, x-rays, and other forms of radiation. They are composed largely of gas and plasma, a superheated state of matter composed of subatomic particles.
Though the most familiar star, our own sun, stands alone, about three of every four stars exist as part of a binary system containing two mutually orbiting stars.
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