Do lights in equal distance away from you have the same brightness?

Do lights in equal distance away from you have the same brightness?

The intensity or brightness of light as a function of the distance from the light source follows an inverse square relationship. Notice that as the distance increases, the light must spread out over a larger surface and the surface brightness decreases in accordance with a “one over r squared” relationship.

Are Cepheids red giants?

Cepheid Variables All stars, late in their lifetime, change from being average stars for their mass ( main sequence stars ) to becoming swollen red giants . Cepheid Variables are very large, luminous, yellow stars. They change in brightness very regularly with periods of 1 to 70 days between peaks.

How common are Cepheid stars?

These stars are uncommon in the Galaxy but account for about 10% of the Cepheids known in the Magellanic Clouds. A monumental study by Cecilia Payne-Gaposchkin and Sergei Gaposchkin showed that they are systematically brighter than the period-luminosity relation defined by the stars with asymmetrical light curves.

How do astronomers use Cepheid variables to determine distance?

Through observations of Cepheid variables, astronomers have determined the distances to other galaxies. They compare the Cepheid variable’s apparent brightness with its intrinsic brightness. The difference between observed and actual brightness yields the distance.

Why is it so hard to see the bulge at the middle of the Milky Way galaxy with visible light?

Why is it so hard to see the bulge at the middle of the Milky Way galaxy with visible light? There is a lot of gas and dust in the way. The three types of galaxies are called: Elliptical, Spiral and Irregular.

How do you measure distance to a galaxy?

For more-distant galaxies, astronomers rely on the exploding stars known as supernovae. Like Cepheids, the rate at which a certain class of supernovae brighten and fade reveals their true brightness, which then can be used to calculate their distance.

Does the universe have an edge?

There is no evidence that the universe has an edge. The part of the universe we can observe from Earth is filled more or less uniformly with galaxies extending in every direction as far as we can see – more than 10 billion light-years, or about 6 billion trillion miles.