# Why exactly is the moon's orbit becoming more circular?

Okay, so I've been pretty interested in this lately. I've been searching this up lately and haven't been able to understand any of the answers I've found. Can someone help me out on this? I know how tidal locking works, I'm just not sure how the tidal mechanics is making the moon's orbit more circular. Can someone help me out on this?

Update:

Please be as simple as possible, because I'm stupid :/

Relevance
• Zardoz
Lv 7
6 months ago

The tidal forces between the Earth and Moon are stronger at perigee than at apogee. This stretches both Earth and Moon. That stretching is resisted. Like air resistance slowing the back and forth of a pendulum, the deformation of the Earth and Moon dampens the back and forth from perigee to apogee.

Source(s): [n] = 10ⁿ
• 6 months ago

Your first citation https://yarchive.net/space/orbits/tidal_circulariz... gives some nice rational, but no actual data. The arxiv.org paper discusses stars, which are fluid. It doesn't talk about moons, which are solid and semi-rigid. I also checked the JPL ephemeris for the Moon, from 9900 BC to 9900 AD (19799 data points). The osculating orbit eccentricity doesn't seem to follow any simple trend. Instead it bounces around in a very complex way, between 0.010 and 0.094. Maybe 19,799 years is to short to show a trend.

• ?
Lv 7
6 months ago

The elliptical movement is slowly absorbed by deforming the moon/ satellite until all that is left is a circular orbit where gravity is constant, much like a wieght on a spring stops bouncing.

• cosmo
Lv 7
6 months agoReport

The analogy is a good one. The deformations caused by tidal distortions are only partly elastic, and to the degree that they are dissipative they tend to circularize the orbit.

• 6 months ago

it is like a Spinning Top

If you imagine starting to spin it

It will not spin steady and upright until it is up to speed

As it Happens in Space which is Frictionless it takes Billions of Years

Very far in the Future the Earth and the Moon Will be completely Gravitationally locked

The Moon will reach its Optimum Velocity and Altitude

And Earth will be rotating at the same rate as the Moon's Orbit, Showing the Same face constantly to the Moon

The Fulcrum of the system finally being external to The Earth's Surface

It will be the same as the Plutonium System with Both Pluto and Charon Tidally Locked to each Other

Albeit at 90 Degrees to the Plane

Source(s): Pluto Solar Eclipse
• daniel g
Lv 7
6 months agoReport

Earths rotation and moons orbit will never lock for the difference in mass. Check out the link in my post.