What is a sidereal year?

[@АмаліяБерінчик]

Thanks a lot

[@narqiez4669]

You explain it very clearly! Thank you! :)

[@Karl-w1f]

Do have a version of this video for the more accurate to observable reality, heliocentric cosmology?

[@anopheles4417]

thank you sir.

[@chrisg3030]

Thanks for your clear explanation taking us with unusual patience and care through the whole cycle. At the end you say 12:15 "what's happened throughout one calendar year, one entire sidereal year, is that the time it takes for the sun and that star to line up exactly in the sky, well that's about 365 and one quarter days, that's one sidereal year. That's slightly different from a tropical year. In the next video I will discuss what a tropical year is". I can't find that video. Could you give me a link? And/or maybe clarify the difference. Wikipedia defines "the sidereal year (or sidereal orbital period), which is the time it takes Earth to complete one full orbit around the Sun as measured with respect to the fixed stars, resulting in a duration of 20 minutes longer than the tropical year". So is it the end of the tropical year that you're referring to at position 7 in the drawing when you say "the star appears just a smidge to left of the sun" (11:50). And if we wait another 20 minutes will they line up exactly and that's our sidereal year?

[@dillontrelawny6417]

Glad you enjoyed the video! I must not have made that video after all, sorry. The difference is that a tropical year is the time from the March equinox in one year to the very next March equinox the next year, equal to about 365.2422 days. This turns out to be about 20 minutes less than a sidereal year. This is due to the Earth's axis precessing in the same direction as it orbits the Sun.

[@chrisg3030]

@@dillontrelawny6417 Thanks. So does it make sense to say that were it not for precession, the sidereal and tropical year would coincide?

[@dillontrelawny6417]

@@chrisg3030 Yes I believe so.

[@chrisg3030]

@@dillontrelawny6417 And what if Earth precessed in the opposite direction to its orbit round the sun? Would the tropical year take 20 minutes longer than the sidereal?

[@dillontrelawny6417]

@@chrisg3030 presumably yes, assuming Earth’s orbital speed and precessional speed remain the same. Some really neat thought experiments indeed at the very least!

[@rodneybaker2629]

If our reality is solar days because we wake up some time around sunrise each and every morning, why bother explaining sidereal days in the context. Explain it in the context it is used in if any.

[@aashishsindhu8628]

Bolo tera bhi Joginder

[@harsh9023]

Kya bol rha hai bhai ? 😂

[@54321Truth]

This proves we do not live on a tilted globe orbiting the sun. What does your wrist watch say at position 1? What does your wrist watch say at position 5? We should have to adjust our wrist watch by 12 hours every 6 months or 4 minutes per day.

[@contagiousintelligence5007]

Our time (24 hours) is in relation to the Sun, not a distant star .

[@54321Truth]

@@contagiousintelligence5007 I was filming a model and realized this. 24 hours is actually a little more than 360 degree rotation of earth.

[@sanjana3711]

@@54321Truth 361 degrees

[@rodneybaker2629]

@@contagiousintelligence5007 It is all smoke and mirrors. We experience solar days as our reality, but solar days don't bring on seasonal changes, only sidereal days do that. That is why they show sidereal days and explain seasons with it.