outerspace unit

Unit Reflection
In the second unit we learned about the Nebular theory. The Nebular theory states that the solar system began as a huge cloud of dust and gas called a nebula, which later condensed to form the sun and its nine planets. The sun was the first to form. The nebular theory says that shock waves from a supernova disrupted a nearby nebula. The nebula began to rotate, and gravity pulled more and more matter into a central disk. The disk became the sun. Clumps of gas and dust around the sun formed the planets and other objects in the solar system. Soon protoplanets formed. There are the inner and outer planets. The difference between them is the inner planets are solids and the outer planets are gasses. The inner planets are near the sun. The sun boiled away most of their lightweight gases and they became solid. The inner planets include Mercury, Venus, Earth, and Mars. The outer planets were less affected by the sun so they kept their lightweight gases. They...