source: How long is a day?⌚ | How long is a day?⌚ | By StarTalk | Facebook
What
- “Sidereal” means related to the stars.
- Time it takes for the Earth to rotate 1 full cycle is 23h56m4s.
- That when the stars be on the same place in the sky.
Why
- We don’t base our lives on when stars return to the same spot in the sky, we base our lives on when the sun returns to the same spot.
- We need sunlight to operate and grow plants.
- When the Earth complete a revolution, it also moves a bit (almost 1 degree) along its orbit around the sun. ⇒ the sun not in the same spot but the stars still because they are very far away.
Hence
- The Earth need to rotate a bit more so that sun get back to the same spot. ⇒ That’s a solar day.