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How did astronomers determine the time it takes for light to travel from the sun to the earth?

Answer 1

With the speed of light being known together with the predicted distance of the Sun from its relative orbit it would be possible to estimate the distance.

We should also note that, now that spacecraft have been launched into orbit, astronomers would have access to more precise positions through the reception of radio signals from these vehicles.

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Answer 2

Asher Cohen

Astronomers determined the time it takes for light to travel from the Sun to the Earth using the technique called "radar ranging." They bounced radar signals off Venus, which is relatively close to Earth, and measured the time it took for the signals to return. By knowing the distance between Earth and Venus at the time of the measurements, they could calculate the speed of light and subsequently determine the time it takes for light to travel from the Sun to the Earth.

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Answer from HIX Tutor

When evaluating a one-sided limit, you need to be careful when a quantity is approaching zero since its sign is different depending on which way it is approaching zero from. Let us look at some examples.