--- Olhomorto@aol.com wrote:
A friend forwarded an e-mail w/ an attached image that purports to show a simultaneous rising sun and setting moon at the north pole. It makes the moon appear many times bigger than the sun, so I'm skeptical that it is authentic.
Clearly not authentic - unless the Moon suddenly rushed up to about 50,000km anyway - and then rushed back to usual orbital position at around 384,000km distant - without anybody noticing. Although the angular size of the Moon does increase and decrease such that variations can be seen with the naked-eye, it's angular size never really varies that much - it's about 1/2 degree. Similarly, the Sun has an angular size of about 1/2 degree. In the photo, the Sun appears to be 1/2 degree, given the TFOV of most 35mm SLR cameras is around 30-35degrees. The Moon is clearly oversized and distorted. Here are some photos illustrating the relative angular size of the Moon at apogee and perigee. http://www.fourmilab.ch/earthview/moon_ap_per.html We usually experience these changes in distance to the Moon as a sense of an "unusually bright full Moon" when the Moon's orbital position at perigee coincidences with the full Moon. Although I have personally noticed this effect, there is a "Bad Astronomy" page that claims the change is too small such that most people do not notice it. The Biggest, Brightest Moon? Week of December 19, 1999 http://www.badastronomy.com/bitesize/fullmoon_perigee.html ("The Moon is actually (4066252 - 3566542)/(4066252) x 100 = 23% brighter at perigee than apogee, . . .") - Canopus56 (Kurt) P.S. - The Moon's perigee is at 363,104km with an angular size of about 0.4923°; its apogee 405,696km with an angular size of about 0.5548°. __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com