The moon’s distance – calculations explained

The second diagram below shows the minimum distance for an object to be seen by half the planet simultaneously. Any farther, then, like the sun, half the planet would see the object and its distance could not be calculated using rise/set observations. But the moon cannot be observed simultaneously over 180˚. For example, when it …

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The Speed of Light

It was not until man began to explore the universe with telescopes that he began to consider the question of the speed of light. In the early seventeenth century, the famous Italian scientist, Galileo, first attempted to measure the speed of light, unsuccessfully. But, about fifty years later, the Danish astronomer, Ole Römer, in 1676, measured the speed of light by …

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