October 16, 2007 Issue

Physics To Go 35 - Blue sky from space/planets

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Physics in Your World

Positions of the Planets image
image credit: Jay Ouellet; image source

Positions of the Planets

This Astronomy Picture of the Day (high-res image) shows Venus, Saturn (at lower left) and the moon early in the morning of 10/07/07. For more details, visit APOD.  What would be the relative position of these objects one lunar cycle later, on 11/04/07? For the positions of the inner planets, see Solar System Live.

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Physics at Home

Your Sky

To make star maps on your computer screen, visit Your Sky, by John Walker.


From Physics Research

The Top of the Atmosphere image
Image credit: NASA; image source

The Top of the Atmosphere

In this NASA image (high-res version) captured from the International Space Station (ISS), the top of the blue band marks what is often called the edge of Earth's atmosphere, about 100 km up.  Note the moon, faintly visible in the left-center.  To learn more, visit The Top of the Atmosphere.

The altitude of the ISS ranges from about 350 km to 450 km. Even at this height, atmospheric drag slowly degrades the orbit, so periodic boosts are required (see NASA's S'Mores), especially when intense solar activity puffs out parts of the atmosphere.

Worth a Look

The New York Times on AOL: Sputnik

Fifty years ago, the Soviet Union shocked the world by beating the US into space with Sputnik, a beach-ball-sized satellite whose radio beeps proclaimed the Soviet triumph. To learn about Sputnik, you can visit the NASA Sputnik site.

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