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Photometric parallax method

The photometric parallax method is one way that scientists measure how far away stars are from Earth. It's kind of like using a ruler to measure how long a piece of string is.

Stars give off light, which we can measure. But the farther away a star is, the dimmer its light appears to us on Earth. So, scientists have found a way to estimate the distance of a star based on how bright it appears from our perspective.

To do this, they compare the brightness of the star to what they expect its brightness to be if it were at a known distance from Earth. This is like comparing the length of a piece of string you want to measure to a string of a known length. From this comparison, scientists can estimate how far away the star is.

This method is called "parallax" because it relies on observing how the star appears to move compared to the much farther away background stars, as the Earth orbits around the Sun. This movement is very tiny! Think about sticking your thumb up and looking alternately at your left and right eye with one eye closed. Your thumb appears to move slightly even though it hasn't actually moved at all. The same effect happens with stars as the Earth moves around the Sun. By measuring how much the star appears to move, scientists can work out its distance.

So, the photometric parallax method is a way that scientists use to estimate the distance to stars by comparing their brightness with what they would expect at a known distance, while also considering the tiny movement of stars in the sky as the Earth orbits around the Sun.
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