(This Franklin Fact was prepared by Franklin Institute Chief Astronomer Derrick Pitts)

It's important to understand that as the earth whirls through space, it blocks the light of the sun. The shadow it creates provides us with "night." Night is when we generally observe the depths of the universe.

But during the limited time of twilight, just after the sun sets and before darkness falls, is the time that we can see satellites. You can look for the Hubble space telescope, international space station Alpha or even any of NASA's space shuttles, when sent to serve the space station. They look like bright moving stars.

During evening twilight this fall, our solar system's two biggest planets, Jupiter and Saturn, are easily seen in the east as two brilliant star-like objects. The brilliant planet Venus can be seen in the western sky. In the morning it's Mars and Mercury in the east. Remember: stars twinkle, planets don't. Watch the sky as earth rotates into night some evening. You'll be amazed at what you can see.

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