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Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer. 2012 March 12 The Scale of the Universe - Interactive Flash Animation Credit & Copyright: Cary & Michael Huang Explanation: What does the universe look like on small scales? On large scales?
The StarChild site is a service of the High Energy Astrophysics Science Archive Research Center (HEASARC) , Dr. Alan Smale (Director) , within the Astrophysics Science Division (ASD) at NASA/ GSFC . StarChild Authors: The StarChild Team StarChild Graphics & Music: Acknowledgments StarChild Project Leader: Dr. Laura A. Whitlock Curator: Responsible NASA Official: If you have comments or questions about the StarChild site, please send them to us .
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The Soyuz TMA-08M rocket launches from the Baikonur Cosmodrome in Kazakhstan on Friday, March 29, 2013 (Thursday, March 28, U.S.
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Welcome to Celestia ...
.br 1) Use checkboxes (Seconds, Minutes, etc) to choose time interval. "Hours" and "Days" work best for animation. Use slidebar at right to control simulation speed. There are 7 speeds, 3 forward (right), 3 reverse (left) and one neutral (center).
Copyright Antonio Cidadao . Used by permission. Click on picture to see large version. From any location on the Earth, the Moon appears to be a circular disk which, at any specific time, is illuminated to some degree by direct sunlight. Like the Earth, the Moon is a sphere which is always half illuminated by the Sun, but as the Moon orbits the Earth we get to see more or less of the illuminated half. During each lunar orbit (a lunar month), we see the Moon's appearance change from not visibly illuminated through partially illuminated to fully illuminated, then back through partially illuminated to not illuminated again.
The revolution of the Moon around the Earth causes the Moon to appear to change shape in the sky. These apparently different shapes are called "phases" of the Moon. The Moon passes through a cycle of eight phases which repeats itself every 29.5 days. There is no definite starting point for the cycle, but phases follow one behind the other in a strict order. Below you will find photographs of each of the eight Moon phases as well as the names and a brief description of each phase.
If you watch the moon every night, you see its shape appear to change. Does the moon really change shape? Of course not, but its appearance from Earth certainly changes. How does this work? The answer lies within the part of the moon that receives sunlight, and the part of the moon that does not receive sunlight. Let’s look at a diagram of the Earth moon system to figure out how this works.
An Interactive Lunar Odyssey Next time some know-it-all says, "The Moon looks like a crescent because of the Earth's shadow," you can set them straight . Tell them the moon looks different depending on where it is in orbit around the Earth. After all, only half the Moon is ever lit by the sun. And standing here on Earth, we can't always see the lit half. To demonstrate your point, move the Moon in the "Phaser" below and watch it go through its paces as you drag it 'round the Earth.