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How do we measure distances in space?

Answer 1

Distances with in solar system are measured by radars.Near by stars by a method called parallax.Far way stars and galaxies they use Cepheid variables or type Ia supernova s standard candles.,

The speed of radar waves is known and their return echo time is measured. The Earth travels 300 KM in a year's orbit, which is used as a base for measuring the parallax angle and calculating the distance using trigonometry. Cephied variable stars are used as standard candles because their luminosity and pulsation period are related. Red shift is measured and the distance is computed.

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Answer 2

Owen Atkinson

Distances in space are measured using astronomical units (AU), light-years, and parsecs, depending on the scale. Astronomical units are used within our solar system, with 1 AU being the average distance from Earth to the Sun (about 93 million miles). Beyond the solar system, light-years and parsecs are common units, based on the distance light travels in a year and the parallax method, respectively.

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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.