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Moon and Jupiter

September 28, 2013

Jupiter is the giant of our solar system — 11 times wider than Earth, and more massive than all the other planets combined.

And thanks to that great bulk, if astronomers in other star systems are looking for planets around the Sun, Jupiter is likely to be the first one they find.

Astronomers here on Earth use two major techniques to find planets in other star systems. One looks for a planet to pass in front of its star, making the star just a tiny bit dimmer for a few hours. So if Jupiter happens to align in such a way that other star systems could see it cross the Sun, they’d see the Sun’s brightness drop by about one percent.

The other technique looks for a tiny “wobble” in a star’s light as the result of a planet’s gravitational tug. This technique has yielded many planets, including quite a few that are bigger and heavier than Jupiter, and in much tighter orbits around their stars. Jupiter is heavy enough to cause a wobble in the Sun’s light that could be detected by instruments here on Earth.

It might be difficult to actually see Jupiter, though. The planet is much fainter than the Sun, so it would be tough to see through the Sun’s glare.

Jupiter is no problem to see from here, though. Tonight, it rises in the wee hours of the morning, and stands well above the Moon at first light. It’s the brightest object in the sky at that hour other than the Moon, so you can’t miss it.

We’ll talk about the Moon and another planet tomorrow.


Script by Damond Benningfield, Copyright 2013

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