| Volume 14 Issue 1 | January 2008 | |
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| What's Up? -- January 2008 | ||
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This month the Earth, as it revolves around the Sun, reaches a point in its orbit that is called perihelion. This is the minimum distance that 
separates the Earth from the Sun. During the first few days of July, half an orbit
later, the Earth is at aphelion, its maximum separation from the Sun.
This is due to
the shape of the Earth's orbit being elliptical rather than circular.
However the Earth has an mildly elliptically-shaped orbit that is closer to being
slightly out-of-round than the incorrect, very elliptical orbit that is shown in
most astronomy textbooks.
(see the next page for more on this eccentric idea) A result of this is that many of my students have a mental image of the Earth in an oval-shaped orbit around the Sun. This is a preconception that I 'attack' with gusto! And of the many things that spark conversation in my Astronomy classes probably one of the most fascinating to discuss with my students is the idea of how we have seasons on our planet. The discussion usually follows the assignment where they consider the following questions: Many people think that we have seasons on earth because we are closer to the sun in the summer than in the winter. |
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