The diagram below shows the orbital paths of

The diagram below shows the orbital paths of Earth, Mars, Jupiter, and a comet named Wild 2. What is the approximate distance between the Sun and Wild 2 when this comet is closest to the Sun? (1) 150 million kilometers (2) 228 million kilometers (3) 778 million kilometers (4) 820 million kilometers

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a e r A a c i t p i l l e ll t s t i b r o l ? e m a s e h

• If the foci are far apart, the orbit is very elliptical. f 1 f 2 • The closer the foci get to each other the more the orbit becomes a circle. f 1 f 2 f 1 f 2

• If the foci are far apart, the orbit is very elliptical. Most eccentric f 1 f 2 • The closer the foci get to each other the more the Which ellipse is orbit becomes a circle. most eccentric? • We measure the shape of the ellipse by its eccentricity. Rounder = less eccentric f 1 f 2 Least eccentric f 1 f 2

In cr f ea si ng ec ce f 1 f 2 f 1 nt ri ci ty f 2 f 1 f 2

When is gravity strongest? When is velocity slowest? When does sun appear largest? When is it summertime in New York?

The diagram below represents the path of the Earth’s orbit around the sun compared to the path of the orbit of a comet around the sun. Which statement concerning the diagram is probably true? (1) A comet has a less eccentric orbit and a shorter period of than the Earth. revolution (2) A comet has a more eccentric orbit and a shorter period of revolution than the Earth. (3) A comet has a less eccentric orbit and a longer period of revolution than the Earth. (4) A comet has a more eccentric orbit and a longer period of revolution than the Earth.