Earth...Days and Seasons

"Hey Sunshine"
Today was one of those days where I tried to do something and something just keep interrupting me,Deja Vu?, yeh, I make mistakes and people do too, that's why we are Humans right? Then why is everyone just bugging me, is it wrong to get back at people? Is it wrong to tell them how I feel? I blanked her today when she called me, is that good? Does she deserve it? Should there be other life on other planets so they suffer like this? Well..that's depends how you look at it right??

Then lets go back to Astronomy..

• The time it takes the Earth to rotate on it's axis is a day.


• The mean solar day is a mean day according to the mean sun.


• Synodic month is a month according to the lunar phases, it is the interval between two moons, which is about 29.5 mean solar day.


• Mean Tropical Year is made to help so we don't get confused with the dates every year.


• Sidereal Day is a day according to a fixed star, meaning if you point at a star and the time it takes for you to come back to the same point is your Sidereal Day.


• Sidereal day is about 23 hours 56 minutes 4 seconds .


• Earth Rotates 360 degrees in a sidereal day, so therefore it turns 361 degrees for a solar day, which means the amount of degrees the Earth has to turn to come to same position as the Sun was before.


• Sidereal day is 3 minutes 56 seconds shorter than the mean solar day, so the difference between sidereal and solar day is that a given star rises 4 minutes earlier everyday.


• You see other stars because the Earth goes around the Sun.
  
• A sidereal year is the time taken for the Earth travel around the Sun in respect to the fixed stars, which is about 365. 256 years, so after one sidereal year the sun will appear in the same position against the star background.
  
• The Gregorian calendar work according to the cycle of seasons and the mean tropical year which is about 365.242 days, which means that the Mean tropical year is measured from one spring equinox to the next.


• Mean tropical year is 20 minutes shorter than the sidereal year because of the, because of the changes of the equinoxes every year.


• We now the Gregorian Calender which means the days are rounded up to 365 days per year so that people around the world is not getting confused when they travel around the world, which means that our calendar now makes a error of 1/4 days per year.


• Obviously which means that after 4 years an extra day is added to keep up with the seasons.


• These years are called leap years, but it still leaves an error of 0.008 days each year, corrected by a special rule, but these can only be leap years if it's divisible by 400 without having a remainder.

Ahhh was that too long?? Well, just a couple more!!

• An obliquity is the tilt of a planet, Earth is tilted 23.4 degrees which means that the Earth's obliquity is 23.4 degrees.


• Earth obliquity might have being different when it first because the moon must have stabilized it, which could mean that obliquity gives us seasons, and made this planet suitable for life.


• Mars and Saturn's obliquity is similar to Earth so the seasons re similar, obviously orbit matters, but Mercury and Jupiter have it's obliquity close to Zero so they do not have much planets.


• Obliquity of Uranus is about 98 degrees, so it does have seasons but it is different to Earth's seasons.
  

By looking at the picture above you must have been able to figure out that while Northern Hemisphere has Winter, Southern Hemisphere has summer because southern hemisphere is closer to the sun than the northern hemisphere. ( That's a lot of confused cut short to easy understandable diagram.) LOL.

• In winter the Sun's radiation touches the Earth at a shallow angle and days are short which explains why Winter cooler.


• In Summer the Sun's radiation touched the Earth steep angle and the days are shorter which explains why summer is warmer.


• In winter the Sun rise from the South - East and sets in South - West.


• At equinoxes Sun rises in east and sets in West.


• In summer Sun rises in north-east and sets in north-west .
  

That's all for today!!

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Simplicity is the ultimate sophistication. Leonardo da Vinci