3 ms·
I was recently looking at some data about day lengths, and basically it all boils down to the fact that the earth doesn't orbit the sun in a perfect circle, whi
by Manu40 4y ago
I was recently looking at some data about day lengths, and basically it all boils down to the fact that the earth doesn't orbit the sun in a perfect circle, which causes slight accelerations and decelerations; along with its wobble. That wobble as I understand is due to the effect of tidal forces due to the moons pull on our ocean.
Tropical/Solar days = 24 hours
But
Sidereal = 23 h 56 min 4.0905 seconds
Why the difference?
Because of those prior mentioned forces causing the location of the sun to be slightly out of alignment from where it started the day prior. Or something like that.
Tropic/Solar days are determined by the position of the sun, as per the name.
Sidereal are based upon the position of the stars. or so I understand.
To be clear. I am not an expert. I am just regurgitating what I read from NASA.
- Telemark70 4y agoThe difference between the solar day and the sidereal day is caused solely by the progress of the earth in its orbit. After 23 hours 56 minutes the earth has made a full rotation relative to the stars. But it has to turn for a further 4 minutes to get the sun to be above the same place on the earth. The difference between the day lengths is one day divided the number of days in a year, i.e. approximately 24 hours / 365.
- Manu40 4y agoYeah, that's basically exactly what I said but with different words. Also, wobble does play a factor. You may want to look into it again some more. https://singularityhub.com/2022/08/07/the-length-of-earths-days-has-been-mysteriously-increasing-and-scientists-dont-know-why/#:~:text=Apart%20from%20these%20large%2Dscale,a%20millisecond%20in%20either%20direction https://singularityhub.com/2022/08/07/the-length-of-earths-d.... > Apart from these large-scale changes, over shorter periods weather and climate also have important impacts on Earth's rotation, causing variations in both directions. The fortnightly and monthly tidal cycles move mass around the planet, causing changes in the length of day by up to a millisecond in either direction.