I feel like I need to explain this "concept" that an object has an "axis" that it spins around...oh! And it's imaginary! I know, the confusion is high in the Upper West Wing at Renaissance Academy... There is an axis of rotation among spinning objects... and even body parts have an axis of rotation! Now aren't you glad we are only talking about the "axis of rotation" in the planet EARTH? The earth rotates about an imaginary line that passes through the North and South Poles of the planet. This line is called the axis of rotation. Earth rotates about this axis once each day (approximately 24 hours). The object spinning on an imaginary axis can be a tiny particle, smaller than a single atom. Or it could be a star with the mass of a thousand suns. Every planet in our solar system rotates on its axis. So, each planet has a North and South Pole, the points where an imaginary axis meets the planet's surface. Some planets, such as Mercury, Venus, and Jupiter, have axis that are almost completely perpendicular, or straight up-and-down. Earth's axis is not perpendicular. It has an axial tilt. Axial tilt is the angle between the planet's rotational axis and its orbital axis. Earth's axis appears stable, but it actually wobbles very slowly, like a spinning top. It takes Earth's axis about 26,000 years to complete a circular "wobble." Earth’s axis helps determine the North Star, and axial "wobble" helps change it. Currently, for instance, Earth's axis points toward a star called Polaris. Polaris, which gets its name because it is almost directly above the North Pole, is the current North Star. Polaris will not always be the North Star, however. The Earth's axis is slowly wobbling away from Polaris. In another 13,000 years, it will point toward the new North Star, a star called Vega. Something like that. It's called "Precession", I like "wobble" personally. People understand "wobble"..
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Mrs. TaylorI love science! Everything about the world is interesting and never boring. I love to study plants, animals, insects, and people. My favorite subjects are my students who are the most unique organisms on the planet! Categories |