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The Question
(Submitted April 14, 1997)
Perhaps you can settle a heated debate between my wife and I and thereby
preserve domestic tranquility.
Can you visually locate and observe SATELLITES from a rural area (Wisconsin)
with the unaided, naked eye?
The Answer
We don't get called on for domestic disputes too often, but here goes...
You can see satellites pass overhead from a dark site, such as rural
Wisconsin. What you see is sunlight reflected from the satellite: since the
satellite is higher up in the sky, it may not be in the Earth's shadow even
though you are (otherwise it would not be night!). You can tell that an
object you see is a satellite rather than a plane or star because it will
move steadily across the night sky over the period of a few minutes, often
"disappearing" as it crosses into the Earth's shadow. As the night progresses,
you will see satellites "disappear" closer to the horizon until after several
hours after sunset, even satellites in low Earth orbit (about 200-800 miles
above the Earth's surface) will be in the Earth's shadow. Satellites in
geosynchronous orbits are high enough (about 22,000 miles up) that they will
almost always be sunlight, but they are too far away for them to be visible.
The space station Mir occasionally passes overhead in the evening sky
in the United States after sunset and can be seen. You can check for
information on Mir passes with astronomy magazines. There may be similar
information available (though I have not seen it) for the space shuttle
during their flights and/or for other large satellites such as the
Hubble Space Telescope.
We hope this settles your domestic issue amicably...
Jesse Allen
for "Ask a High-Energy Astronomer"
Questions on this topic are no longer responded to by the "Ask a
High-Energy Astronomer" service. See http://imagine.gsfc.nasa.gov/docs/ask_astro/ask_an_astronomer.html
for help on other astronomy Q&A services.
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