Astronomy
-
Upload
xanthus-fox -
Category
Documents
-
view
24 -
download
0
description
Transcript of Astronomy
Chapter Eighteen: Earth, the Moon, and the Sun
• 18.1 The Earth and Its Moon
• 18.2 Earth Cycles
• 18.3 The Sun
18.3 The Sun
• The Sun is a star.
• A star is a giant, hot ball of gas held together by gravity.
• The Sun is medium-sized compared with other stars in the universe.
Approximately 1 million planet Earths could fit inside the Sun!
18.3 The Sun• Gravity squeezes the
atoms in the core of a star so tightly that they fuse together in a reaction called nuclear fusion.
• In the process, huge amounts of energy are given off.
18.3 Anatomy of the sun
• The corona is the outermost layer of the sun’s atmosphere, extending millions of kilometers beyond the sun.
• Sunspots are areas of gas that are cooler than the gases around them.
18.3 Features of the sun
• Occasionally, large “loops” of gas called prominences can be seen jumping up from groups of sunspots.
18.3 Features of the sun
• Solar wind is an electrically charged mixture of protons and electrons.
• Auroras, called the northern lights, occur when layers of our atmosphere are energized by solar winds.
Research Connection
Solar Observatory
• The staff of Big Bear Solar Observatory study the sun, solar phenomena, and the solar atmosphere.