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Dara and Brenn were playing checkers. Suddenly the checkers floated off the board. Both twins grabbed at handholds as they rose toward the ceiling. There was a low rumbling from the voice synthesizer that reminded Brenn of laughter. "SAM!" Brenn shouted, "you turned off the gravity! Is this a practical joke?"
"My programming permits learned behavior," chuckled SAM. Brenn thought of the jokes he and Dara often played on each other.
SAM spoke again. "Receive information. We approach Neptune. Its diameter is 30,800 mi (49,500 km). The planet is 2,790,000,000 mi (4,500,000,000 km) from the Sun. Neptune spins on its axis in about 16 hours and revolves around the Sun in 165 Earth years. Neptune's gravity is slightly stronger than Earth's. Voyager 2 found that Neptune had four faint rings and eight moons.
"Because of its distance from the Sun, Neptune receives only one one-thousandth as much sunlight as Earth. Neptune daytime will seem dark to you. There is turbulent weather, with winds at 700 mph over many areas. A hurricane about the size of Earth creates an area on the surface called the Great Dark Spot. Winds on the edges of this spot have been measured at over 1,400 mph (about 2,200 km/hr). Temperatures probably never rise above -350+¨ |àí&&orF (-210 -Àí&d&ordC) on Neptune.
"The outer layer of Neptune is all gas, mostly hydrogen, helium, and methane. Deep inside the planet is an icy slush of water, ammonia, and methane surrounding a rocky core. All of Neptune is wrapped in heavy belts of clouds."
"These Gas Giants are fun to explore," said Dara. "Let's get ready, Brenn." When the twins' report on Neptune arrived at Mission Control, some words had been lost.
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QUESTIONS
A mission control specialist made this list of the incomplete sentences. Can you write in the missing words?
1. Neptune spins on its axis in about _________________ hours and revolves around the Sun in ___________________ Earth years.
2. Neptune has ________________ faint rings and _______________ moons.
3. Because of its distance from the Sun, Neptune receives little light. The Neptune day looks ___________ to us.
4. The outer layer of Neptune is all gas, mostly ________________________ , __________________________ , and _____________________________ .
5. The planet has turbulent weather. Over many areas, winds blow at ___________________ mph.
6. It is cold there. The temperature probably never rises above ____________________________.
Writing Assignment: On the back of this sheet, describe what Dara and Brenn found on Neptune. Explain how their findings make sense, considering Neptune's environment.