Earth’s Second Motion Revolution!

Revolution Motion of one object around another. Synonym for revolution, one word? ORBIT!

Earth’s Period of Revolution One year About 365.25 days (rotations)

So what’s up with that 0.25 of a day?

Not Exactly 0.25 days, though http://www.findingdulcinea.com/news/on-this-day/September-October-08/On-this-Day--In-1582--Oct--5-Did-Not-Exist-.html

Assignment Calculate the orbital speed (assume circular orbit), of each planet (including Pluto) Show work. Answer in miles per hour. Use Table 21.1 on P 577 to help answer the following questions

Handout Questions to answer  How long does it take Earth to orbit the sun once? How many rotations occur during one orbit? How long is one typical calendar year? How long is a calendar leap year? Why does a leap year exist? Explain Calculate the orbit speed of each planet Which planet revolves the fastest? Which Planet revolves the slowest? Study your data. Is there a pattern?

Table 21.1 on P 577

Sun Radius or orbit (mi) circ of orbit (mi) years Days Hours speed (mi/hr) Mercury 36,000,000.00 226,194,671.06 88 2,112.00 107,099.75 Venus 67,000,000.00 420,973,415.58 225 5,400.00 77,958.04 Earth 93,000,000.00 584,336,233.57 365.25 8,766.00 66,659.39 Mars 142,000,000.00 892,212,313.62 687 16,488.00 54,112.83 Jupiter 483,000,000.00 3,034,778,503.37 12 105,192.00 28,849.90 Saturn 886,000,000.00 5,566,902,182.16 29.5 258,597.00 21,527.33 Uranus 1,783,000,000.00 11,202,919,402.70 84 736,344.00 15,214.25 Neptune 2,794,000,000.00 17,555,219,748.26 165 1,446,390.00 12,137.27 Pluto 3,666,000,000.00 23,034,157,336.12 248 2,173,968.00 10,595.44