Skip to comments.Astronomy Picture of the Day -- Equinox on a Spinning Earth
Posted on 03/19/2014 4:28:26 AM PDT by SunkenCiv
Explanation: When does the line between day and night become vertical? Tomorrow. Tomorrow is an equinox on planet Earth, a time of year when day and night are most nearly equal. At an equinox, the Earth's terminator -- the dividing line between day and night -- becomes vertical and connects the north and south poles. The above time-lapse video demonstrates this by displaying an entire year on planet Earth in twelve seconds. From geosynchronous orbit, the Meteosat satellite recorded these infrared images of the Earth every day at the same local time. The video started at the September 2010 equinox with the terminator line being vertical. As the Earth revolved around the Sun, the terminator was seen to tilt in a way that provides less daily sunlight to the northern hemisphere, causing winter in the north. As the year progressed, the March 2011 equinox arrived halfway through the video, followed by the terminator tilting the other way, causing winter in the southern hemisphere -- and summer in the north. The captured year ends again with the September equinox, concluding another of billions of trips the Earth has taken -- and will take -- around the Sun.
(Excerpt) Read more at 126.96.36.199 ...
[Credit: NASA, Meteosat, Robert Simmon]
picture of the day on Wikimedia Commons for 26 April 2009 -- Taken by Apollo 8 crewmember Bill Anders on December 24, 1968, showing the Earth seemingly rising above the lunar surface. Note that this phenomenon is only visible from someone in orbit around the Moon. Because of the Moon's synchronous rotation about the Earth (i.e., the same side of the Moon is always facing the Earth), no Earthrise can be observed by a stationary observer on the surface of the Moon.
One interesting thing, to me, is how small the change actually appears to be on the video, compared with how significant it is on our weather. For me, growing up in northern Minnesota, this change meant the difference between -40 degree nights to +100 degree F days. It makes you appreciate how much effect the sun can have on “climate change”.
Designed that way.
The strange things you can do with a ball some string,
some dirt, and a flashlight and camera. To bad they spent
all that money on all the spaceship stuff. Or did they
The NASA channel used to have a show called “Earth Views”, which consisted solely of shots of Earth as taken from the space shuttles. I could, and did, watch that show for hours. I found it absolutely fascinating.
Pictures and threads like this remind me of that show. Thanks for posting.
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