Perigee Moon

This unusual view of the moon was photographed by Ajaz Khan Sanjrani one evening last week on his way to work. That was in Quatta, Pakistan.

_76229264_9d1de797-a3f5-42ea-9a2a-1b3ae7de2dbc   BsgXnasIcAA_ZtC.jpg-large

Tim McCord from Entiat, Washington State, photographed another impressive image.

The moon appears bigger than usual because of its elliptical orbit around the earth, a phenomenon that will be seen again next month on August 10th. It’s called a perigee moon.

toscale  sidebyside

The moon’s orbit around the Earth is elliptical, with an eccentricity of 5.49%. The tidal effect of the sun’s gravitational field increases this eccentricity when the moon is full or new.

MoonOrbitEarth

The combined effects of orbital eccentricity and the sun’s tides result in a substantial difference in the apparent size and brightness of the moon at perigee and apogee. Extreme values for perigee and apogee distance occur when perigee or apogee passage occurs close to new or full moon, and long-term extremes are in the months near to Earth’s perihelion passage (closest approach to the sun, when the sun’s tidal effects are strongest) in the first few days of January.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s