Manmade ‘Stars’ in Summer Skies

Manmade ‘Stars’ in Summer Skies

by Dave Adalian

If you’re gazing skyward on a warm night in late spring or summer and it appears one of the stars has come loose from its moorings to drift across the heavens there’s no need to worry. You’re not imagining things.

What you’re seeing isn’t a star. Instead it is something far closer to home, a satellite.
It used to be the only thing in orbit around the Earth was our moon, but with the first successful rocket launch into low Earth orbit by the former Soviet Union back in the middle 1950s everything changed.

Since then, mankind has peppered the heavens with more than 27,000 artificial satellites, from the huge International Space Station down to bolts, lost tools and bits of discarded trash, even an unlucky astronaut’s glove, all left to drift in space until Mother Earth’s relentless gravity finally coaxes them back for a fiery reentry into the atmosphere.

Of those various bits of stuff we’ve heaved into the sky, some 9,000 of them are still up there, and of those several hundred of are visible to the naked eye.

When you find one of these star-like pinpricks making its stately way through the heavens, what you’re seeing is actually reflected sunlight shining off it. How bright a satellite appears depends on several factors, including how high above the Earth it orbits, its size and how well it reflects sunlight.

During the shorter nights of the warmer months, the tilt of the Earth’s northern hemisphere toward the Sun not only causes summer’s weather, it also causes Earth to cast a shorter shadow. This means more of the satellites soaring overhead are exposed, which makes this the best time of the year to see them.

It also helps that the warmer weather makes it more likely would-be satellite hunters will venture outside.

Among the brightest of satellites is a group known as the Iridium Constellation. Dozens of these communications satellites surround the Earth, producing extremely bright flares on a regular basis.

Another favorite bright target of satellite seekers is the Hubble Space Telescope, which will be making a series of predawn passes throughout May before becoming an evening object again in June.

You can find out when the Iridium satellites, the HST and the ISS will be visible overhead where you live by visiting www.Heavens-Above.com.

The site also provides predicted appearances for dozens of other satellites, along with maps and observing tips.

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The column appeared originally in the Visalia Times-Delta on May 18, 2006.