From UPSC perspective, the following things are important :
Prelims level : Revolution of Earth and other planets around the Sun
Mains level : NA
For us, 365 days make up a year because Earth takes as many days to complete one orbit of the Sun. But have you ever wondered how many days make up a year on other planets?
What determines the length of a year?
- The length of a year on any planet depends on where the planet is orbiting.
- Planets that are closer to the Sun than Earth will have fewer days in a year, while those rotating farther away will take many more days to make up a year.
- This is because of two reasons – planets that are closer to the Sun will take a shorter time to orbit it than those farther away, and the closer a planet orbits the Sun, the Sun’s gravity can pull on the planet, making the planet orbit faster.
Why should we care?
- To send a spacecraft to another planet, we need to know where the planet is in orbit.
- This will help us plan and manoeuvre the spacecraft accordingly.
How long each planet takes to orbit the Sun (in Earth days):
- Mercury: 88 days
- Venus: 225 days
- Earth: 365 days
- Mars: 687 days
- Jupiter: 4,333 days
- Saturn: 10,759 days
- Uranus: 30,687 days
- Neptune: 60,190 days
It’s a mean task to consider this PYQ from 2013, Huh!
Q.Which planet was downgraded to dwarf planet status?