Earth Gravity

The mass and gravity of the earth is steadily rising and the rotational speed is decreasing because of material added from meteorites etc. This change is however negligible and by no means the only change.

The effect on the rotation speed of the earth - moon combination will show the most changes.

I personally think that the size of the moon in relation to the earth qualifies it as our sibling planet. The orbit of the moon seems to confirm this.

The tsunami caused the surface of the earth to temporary shrink by about 20 meters . This caused the earth to a slight increase in rotation speed and a wobble.

The following is an interesting explanation of the earth/moon mechanics and may give an insight into what is going on.

http://www.talkorigins.org/faqs/moonrec.html

....and Newtonian mechanics predicts that the orbiting period of the earthmoon around the sun is inependent of the mass of the earthmoon system, if the equations are correct. Angular velocity = Newton's gravitational constant x mass of the sun / orbiting radius of the earthmoon around it.

Einstein may have had other ideas and one would need to recruit 'Jorrie' to explain them properly.

Hi PWSlack, you said: "Einstein may have had other ideas and one would need to recruit 'Jorrie' to explain them properly."

I'm afraid a 'proper explanation' is outside the scope of a post on the forum.

However, I have this free pdf download on my website, titled: how orbits work, that does a reasonable job of explaining the differences between Newton's and Einstein's orbits.

Regards.

Hi Jorrie,

Just wondered if you've seen this?

Regards,

-John

Hi John, tx, it's very interesting.

I'll have to read more on it before trying to comment, because it is unclear to me what they mean by 'before the BB', which is today reckoned to be at ~10^-34 seconds, when inflation is thought to have started.

Do they mean the time between ~10^-43 (the Planck time) and ~10^-34 seconds? Or do they mean way past that?

-Jorrie

Hi Jorrie,

I find this absolutely fascinating. If you come up with insights on this I, and I'm sure others, would love to hear them.

-John

Can I ?

Hi John.

The Penn State news release gives a bit more on this discovery.

It appears that they are talking about a Big Bounce and trying to model the universe before the bounce, i.e., 'way-back'!

It is essentially 'loop-quantum-gravity' of which I understand very little.

Regards.

Thanks Jorrie

Hi PWS

"Angular velocity = Newton's gravitational constant x mass of the sun / orbiting radius of the earthmoon around it."

I do not understand this statement yours. Can you expand a bit?

I know Newtonian angular velocity in a circular orbit as: ω = √(GM/r³) rad/sec. This is the basis of Kepler's third law of planetary motion.

SL

This is correct. Blame anno domini and a low brain battery voltage for the earlier post. Sorry.

This is incorrect. See post #9. Sorry.

My only argument is that the moon may be big enough to be called a planet.

The dynamics of the earth - moon system will stay the same.

Different bodies revolving around each other are very common.

Hi Hendrik, you wrote: "My only argument is that the moon may be big enough to be called a planet."

I agree with that. Our moon is the only natural satellite in our solar system that is far enough from the 'parent body' to always 'fall' towards the sun. This means that the curvature of the moon's orbit around the sun never becomes negative.

All other moons fall away from the sun at some point in their orbits.

-J

Hello Scruffy

You wrote: the curvature of the moon's orbit around the sun never becomes negative.

For those of use who can't do solid geometry in our heads could you please explain a negative/ positive orbit. I "kinda" know what you mean but don't want to miss your point which sounds intriguing.

Hello Yani.

Normal orbit paths always have positive curvature, meaning that the orbiting object's path has a curvature that is towards the massive object. As far as I know, it is only in 3 or more body orbits that negative curvature of the orbit's path relative to the primary object can happen.

An example is the artificial satellites around Earth's equator. They curve so strongly towards Earth that at least some part of the orbit curves away from the sun. That is negative curvature relative to the sun.

SL

I'm not even going to try and explain this ! There is a lot of chat elsewhere about the moons orbit on CR4 , and also Jorrie could give a far better explanation of all the issues here than I ever could. I must depart for my Chicken coop.

Hi Kris.

This picture gives a wrong impression about the orbit of our moon around the Sun, because it appears as if the dark moon is curving away from the Sun.

As Scruffy has correctly stated above, our moon never curves away from the Sun. At the dark moon, it is actually falling towards the Sun, but Earth is falling towards the Sun faster. Hence the moon is also falling towards Earth, if that makes any sense...

Another way to put it is that the moon is far enough from Earth so that, when on the Sun's side, the Sun has a larger gravitational pull on the moon than what Earth has in it.

Regards.

Thanks Jorrie ,

The text ,which is not legible in the graphic , indicates that it is to illustrate a ..."synodical month , or lunation ,...." . However , to address the orbit issue ;

"moon never curves away from the Sun." - Jorrie (above )

"moon's orbit is always concave to the sun. " - Patrick Moore (Moon Flight Atlas)

< Moore does refer to the Barycentre as well in his above quote>

"I am now confused beyond my normal level " - Kris

Am I missing something about the wording/meanings ?

Last minute thought : PM is referring to the fact that the sequence of blue arrows is concave to the sun ?

Kris

Hi Kris. You wrote: "

"moon never curves away from the Sun." - Jorrie (above )

"moon's orbit is always concave to the sun. " - Patrick Moore (Moon Flight Atlas)"

These two say the same thing. Concave means curving towards the Sun.

No, he did not refer to the "sequence of blue arrows", I think. These represent the moon's orbit relative to Earth. The 'concave' refers to the moon's path relative to the Sun.

The problem with the sketch is that it's not to scale. I one plotted segments of the Earth/moon orbit around the Sun to scale on my PC and then one can see the effect properly.

Regards.

Thanks Jorrie .

I must have been looking at the moon for too long , and shall retire to shave my hands !

Kris

If you are referring to the force of gravity a different points around the Earth, then yes, there are significant differences. These have been known about for years. A satellite was sent up awhile ago to measure gravity over Canada, which seems to have lower gravity than the rest of the land masses in the Western Hemisphere.

Also, the Earth - Moon system is far from stable. The moon is constantly moving away from the Earth. In early prehistoric times, the moon appeared much larger in the sky. Since then, it's moved to its present position. Eventually, the moon will escape from Earth orbit.

Aside from the change in the Earth's mass from cosmic dust, a far more dangerous and pervasive increase in mass is caused by the various collections of National Geographic building up in people's basements.

Good one vermin. LOL

I wouldn't LOL too much - The National Graphics may cause you both to be left permanently on the dark side of the Earth.

Hang on a minute , that's going to do for me as well ! I shall go consult a Globe..

We're sending the National Geos to the newly discovered planet X (see the thread "Dark side of the moon").