Your friend tells you that the sun is obviously the biggest and brightest star in the universe. When you ask her why she thinks that, she says, "Just look at it! It’s way bigger than any star you see at night!" How would you correct her? Use the terms "apparent brightness" and "true brightness" in your response.

I would correct my friend by saying the stars that he is seeing may or may not appear, since the light in time that is captured by our eyes is perceived late.

This means that the stars have a true brightness and an apparent brightness.

When we look at the sky at night, the brightness of the stars is not the same. What I see is its apparent brightness.

More than 2,000 years ago, the Greek astronomer Hipparchus arranged the stars according to size categories, ranging from 1 to 6. Class 6 stars can be seen simply on a moonless night.

The apparent brightness tells us nothing about what the true brightness of that star is. If the observer knows the distance at which this star is from Earth, he will be able to estimate its absolute brightness. If all the stars were at the same distance from us, we could rely on the apparent brightness of their absolute brightness. As a rule, the unit of 10 parsec = 32.6 light years was established. Therefore, it could calculate the brightness of the star, if there were 32.6 light years from Earth.

Explanation:

In synthesis or simple words, that is why the stars could be larger than the sun and be further away and we see them smaller than the sun, while those that are smaller but are closer capable than visually perceive them from a bigger way.

The factors to take into account in this wording are: that the true and apparent brightness is related to distance and size, and that what we see as a star does not always mean that it is still present, it may be that this star is not find it in the system, but when we see the light it emits late, we think so.

a gas, having a molecular weight of 13 kg/kmol and a kinematic viscosity of 0.25 cm2/s, flows through a pipe 0.25 m internal diameter and 5 km long at the rate of 0.4 m3/s and is delivered at atmospheric pressure.