# Naked Science Forum

## Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: bobdihi on 16/06/2018 08:19:57

Title: Does Earth's Orbit vary around the Sun?
Post by: bobdihi on 16/06/2018 08:19:57
Is there any variations in Earth's orbit around the Sun? Meaning the path taken by the Earth around the Sun from year to year. If any , how much they differ?
Title: Re: Does Earth's Orbit vary around the Sun?
Post by: RD on 16/06/2018 08:58:07
Is there any variations in Earth orbit around the Sun? Meaning the path taken by the Earth around the Sun from year to year. If any , how much they differ?
See ... https://en.wikipedia.org/wiki/Milankovitch_cycles#Orbital_shape_(eccentricity)  (https://en.wikipedia.org/wiki/Milankovitch_cycles#Orbital_shape_(eccentricity))
Title: Re: Does Earth's Orbit vary around the Sun?
Post by: evan_au on 16/06/2018 11:21:56
Quote from: bobdihi
Is there any variations in Earth's orbit around the Sun?
Even within a single year, there is some variation in Earth's orbit, due to the eccentricity (slight egg-shape) of Earth's orbit.
- At the closest point in its orbit, Earth is 147 million km from the Sun, around January 4th.
- At the farthest point in its orbit, Earth is 152 million km from the Sun, 6 months later.
- Due to the inverse square law, the intensity of solar radiation is about 7% greater in January than July.

In practice, it means that Northern hemisphere seasons are a little less extreme than you would expect from Earth's tilt
- And Southern hemisphere seasons are a little more extreme.
Title: Re: Does Earth's Orbit vary around the Sun?
Post by: Janus on 16/06/2018 16:06:01
Is there any variations in Earth orbit around the Sun? Meaning the path taken by the Earth around the Sun from year to year. If any , how much they differ?
See ... https://en.wikipedia.org/wiki/Milankovitch_cycles#Orbital_shape_(eccentricity)  (https://en.wikipedia.org/wiki/Milankovitch_cycles#Orbital_shape_(eccentricity))
To illustrate this quote from the link,
"The Earth's rotation around its axis, and revolution around the Sun, evolve over time due to gravitational interactions with other bodies in the solar system. The variations are complex, but a few cycles are dominant.", we can look at these two charts for Keplerian Elements for two different time ranges.