When looking up into the sky at night, you’ve probably noticed that some stars are brighter than others. Ever thought about why this is? Let’s see what our friends at Name a Star Live have to say!
Two Main Factors
There are actually two factors that influence how bright a star appears to our eyes:
1) The Star's Actual Brightness
Some stars are naturally more luminous than others, so the brightness level from one star to the next can be significantly different.
A star’s actual brightness refers to how much power a star has - which can also be explained as the amount of wattage it has (think of light bulbs!). Stars with more power (or higher wattage) will shine brighter than those with less power (lower wattage).
2) The Star’s Distance from Us
However, just because a star looks brighter, doesn’t mean it actually is brighter. A star’s brightness also depends on its proximity to us.
The more distant an object is, the dimmer it appears. Therefore, if two stars have the same level of brightness, but one is farther away, the closer star will appear brighter than the more distant star - even though they are equally bright!
For example, the sun is technically the brightest star when viewed from Earth, but it’s also the closest star to Earth. When you take away the distance factor, the sun is actually in the middle range of brightness when compared to other stars!
Next time you look at the night sky, think of the various combinations of actual brightness and distance that must exist in order to create the beautiful range of brightness levels you see.
Looking for more Never Stop Asking "Why?" questions? Catch up on all of the past "Why's" on the blog!