Current Moon Phase

Waxing Crescent
6% of full

Farmers Almanac
The 2014 Farmers Almanac
Farmers' Almanac

Why Don’t Comets Zoom Across The Sky?

Why Don’t Comets Zoom Across The Sky?

Before answering this question, think about this: Have you ever seen the Moon whiz across your line of sight like a meteor? The answer of course, is no. Even though the Moon is traveling around the Earth at over 2,000 miles (3,200 km) per hour, at its average distance of 239,000 miles (382,000 km) from Earth, its orbital motion is barely perceptible.

The Moon seems to creep roughly its own diameter eastward against the star background. Similarly, although a bright naked comet might be moving at many tens of thousands of miles/kilometers per hour through the inner solar system, its overall distance from Earth likely will measure in tens of millions of miles/kilometers.

So while a bright comet will indeed appear to move, because of its distance from Earth, its apparent night-to-night movement against the background stars is very slow. So it moves across the sky in the fashion of the Moon (or the planets for that matter), not in the fashion of a streaking meteor.

0 comments

There are no comments yet...

Kick things off by filling out the form below.

Leave a Comment

Note: Comments that further the discussion of the above content are likely to be approved. Those comments that are vague or are simply submitted in order to promote a product, service or web site, although not necessarily considered "spam," are generally not approved.

If you notice a hole in the upper left-hand corner of your Farmers' Almanac, don't return it to the store! That hole isn't a defect; it's a part of history. Starting with the first edition of the Farmers' Almanac in 1818, readers used to nail holes into the corners to hang it up in their homes, barns, and outhouses (to provide both reading material and toilet paper). In 1910, the Almanac's publishers began pre-drilling holes in the corners to make it even easier for readers to keep all of that invaluable information (and paper) handy.