Why is the Sky Dark at Night?
2 min read3 days ago
You might be thinking it’s because of sunset.
Well the answer is No…
There are billions of stars all around us,emitting light.So we should be having the night sky bright on the Earth as there is an attack of light from everywhere.
This is known as Olber’s Paradox,given by Henrich Wilhelm Olber in 1823.
It states that;
If the universe is endless and uniformly populated with luminous stars then every line of sight must eventually terminate at the surface of a star.
But that doesn’t happen.
So ,
Where does the light from these stars disappear?
The main reasons for this are;
- The universe is expanding.So the light from distant stars in its way gets stretched to the red part of the electromagnetic spectrum,known as Red Shift,which is not visible to a naked human eye.
- The universe is a finite age.The age of the universe is 13.8 billion years ago.So the light didn’t have enough time to reach us.
- Interstellar Absorption: The universe is not fully empty,it contains dust and gases.While light is travelling some light is absorbed and scattered by them,making light dimmer and harder to see.
The sky is dark at night,
In the midst of the speed of light and the speed of the universe’s fight.
Thank You
