• Security incident: ISF was recently accessed by intruders. Please change your password, and change it anywhere else you used it. Read more

Moon facts as we know. Hollow, wobble, orbit etc?

codell23

New Blood
C
Joined
Mar 1, 2005
Messages
3
So far my searches didn't turn up anything here on this, likely because it's silly.

I'm having a discussion with my very quick to believe anything posted on some bs website friend and we are talking about the moon.

He read things that said it's orbit was unique and didn't behave like any other moon that we know of, he also says it doesn't wobble (and should since it's lopsided?) and has earthquakes for 3 hours, hence he thinks all of this means it's hollow.

Now I found some good info to explain the composition of the moon and it's basic orbit. But I am having a hard time finding good info on the wobble or lack of, wether or not it's perfectly round and has a heavy side etc.

Would any of you be willing to point me in the right direction?

I'm getting the old "we don't know anything" and "scientist argue all the time so it might be true" bs from him. While I agree on those points somewhat I think we do know some things and we can't just start wondering if the moon might be an artificial satellite moved here by aliens simply because some people don't have the current facts on hand.

Thanks in advance.
 
You need to ask your bs website friend for his sources about the wobble, 'earthquakes for 3 hours' (and why this means that the Moon is hollow), heavy side, etc.

The Moon's orbit is only 'unique' in the same sense that every orbit is unique, i.e. has its own parameters.

It is not perfectly round:
Equatorial radius 1,738.14 km (0.273 Earths)
Polar radius 1,735.97 km (0.273 Earths)

It is not hollow: NASA Research Team Reveals Moon Has Earth-Like Core
 
Reality Check said:
<snip>

It is not perfectly round:
Equatorial radius 1,738.14 km (0.273 Earths)
Polar radius 1,735.97 km (0.273 Earths)

<snip>
Click to expand...


Huh.

That's pretty darned round.

If someone had given me a multiple choice question about the moon's roundness I probably wouldn't have picked that answer just by guessing. It almost seems too round.

Maybe that proves it's an alien spaceship.
 
quadraginta said:
Huh.

That's pretty darned round.

If someone had given me a multiple choice question about the moon's roundness I probably wouldn't have picked that answer just by guessing. It almost seems too round.

Maybe that proves it's an alien spaceship.
Click to expand...

Well, maybe not an alien spaceship, but it does prove it is completely hollow....and unique.
 
Why would a lopsided artificial satellite not wobble?
 
codell23 said:
we can't just start wondering if the moon might be an artificial satellite moved here by aliens
Click to expand...

How old does he think the Moon is? My mind reels at the thought of a civilization powerful enough to move our Moon AND then continue developing for billions of years.
 
Thanks Reality Check for the links! I added a few more here on the moonquakes and wobble but I haven't posted enough so it blocked the links, I'll add them later if this try doesn't work.

Now if only my otherwise intelligent friends would stop believing every theory posed on Ancient Aliens heheh.
 
lets try this... (replace "DOT" with ".")


scienceDOTnasaDOTgov/science-news/science-at-nasa/2006/15mar_moonquakes/

and it wobbles...

youtubeDOTcom/watch?v=FCKmZXhVvkQ
 
Hollow Moon?

Think about Newton's gravity equations.

Now think about Moon's orbit, think about tides, think about the orbits of our crafts around the Moon.

At last, think about a hollow Moon- this means less mass.

Thus, the Moon is not hollow.

Note super-duper-uber science was not required to reach such conclusion...
 
codell23 said:
I'm getting the old "we don't know anything" and "scientist argue all the time so it might be true" bs from him. While I agree on those points somewhat I think we do know some things and we can't just start wondering if the moon might be an artificial satellite moved here by aliens simply because some people don't have the current facts on hand.
Click to expand...

May I suggest this classic essay by Isaac Asimov: http://chem.tufts.edu/AnswersInScience/RelativityofWrong.htm

(from which the quote in my sig. is taken)
 
codell23 said:
lets try this... (replace "DOT" with ".")


scienceDOTnasaDOTgov/science-news/science-at-nasa/2006/15mar_moonquakes/

and it wobbles...

youtubeDOTcom/watch?v=FCKmZXhVvkQ
Click to expand...
Moonquakes is a NASA article about the Apollo observations that quakes occur on the Moon. This same data provided the evidence that the Moon has a core (NASA Research Team Reveals Moon Has Earth-Like Core).

The YouTube video has this description:
Even though the Moon shows the same basic face to the Earth, it wobbles slightly because its orbit is not perfectly circular and its axis is not aligned exactly with Earth's. This movie shows the portion of the Moon visible to the Earth over several months around the time when radar data of the south polar region of the Moon was collected (Courtesy of NASA)
Click to expand...
Standard orbital mechanics. Any orbiting mass with an elliptical orbit and non-aligned axis with the primary body will do the same.

This of course has nothing to do with the fantasy that the Moon may be hollow. All that matters for the orbit (and its wobbles) is the mass and the misalignment of the axis.
 
Correa Neto said:
Hollow Moon?

Think about Newton's gravity equations.

Now think about Moon's orbit, think about tides, think about the orbits of our crafts around the Moon.

At last, think about a hollow Moon- this means less mass.

Thus, the Moon is not hollow.

Note super-duper-uber science was not required to reach such conclusion...
Click to expand...

This.

We know the moon's surface gravity - for one thing, astronauts measured it. We also know its radius. From that, we get its total mass - and, if we assume it's a solid ball of uniform density, I'll bet the density comes out to a bit greater than that of ordinary rock. (Feel free to check, or I'll do it for you if you get stuck.)

If on the other hand the moon is hollow, given the thickness of the crust we can compute the density - and it's going to be much greater than that of rock (unless it's just a little hollow, which presumably isn't what your friend meant). It also has to be very strong, because a hollow shell would tend to collapse under its own gravity.

So, ask your friend - how thick is the shell? What's it made out of? Does that add up?
 
Last edited:
It's made out of unobtainium, and is exactly as thick as it needs to be, and as strong as it needs to be, and as dense as it needs to be to fool us.

Obviously. Super-smart, intergalactic traveling aliens wouldn't make a mistake like that.
 
sol invictus said:
This.

We know the moon's surface gravity - for one thing, astronauts measured it. We also know its radius. From that, we get its total mass - and, if we assue it's a solid ball of uniform density, I'll bet the density comes out to a bit greater than that of ordinary rock. (Feel free to check, or I'll do it for you if you get stuck.)

If on the other hand the moon is hollow, given the thickness of the crust we can compute the density - and it's going to be much greater than that of rock (unless it's just a little hollow, which presumably isn't what your friend meant). It also has to be very strong, because a hollow shell would tend to collapse under its own gravity.

So, ask your friend - how thick is the shell? What's it made out of? Does that add up?
Click to expand...

Well, sure it is solid now. They replaced the hollow one with a solid one in the 1950s.
 
Hollow Moon

codell23 said:
... he also says it doesn't wobble (and should since it's lopsided?)
Click to expand...


As RC points out, the moon does "wobble" (for appropriate definitions of wobble), which is illustrated in the YouTube video he linked. The motion is called "libration" (the movie in the Wiki page maybe even better than the YouTube video). However, being lopsided will cause the moon to stop wobbling faster than it would if it were not lopsided, because the tidal gravity of Earth can grab the lopsided mass asymmetry, thus tidally locking the moon more quickly than if it had nothing to grab. If the moon were free-floating, and not orbiting Earth or anything else (except the sun) than being lopsided would have little to do with whether or not it wobbled.

codell23 said:
and has earthquakes for 3 hours, hence he thinks all of this means it's hollow.
Click to expand...


I too have no idea what "earthquakes for 3 hours" is supposed to mean, but just guessing, you must remember that the speed of sound is not instantaneous any more than is the speed of light. It takes time for seismic waves to rumble around the moon, and that may be where the "3 hours" comes from. But that would in any case have nothing at all to do with hollowness (or lack thereof) for the moon.

But we know that moon is not hollow for the same reason we know Earth is not hollow. There are seismometers on the moon left behind by Apollo astronauts. Artificial impacts, meteorite impacts, and moonquakes all set up acoustic vibrations detected by the instruments as the waves pass through the moon. In that we we can tell what the moon is made of to a depth of roughly 1000 km (which is most of its roughly 1737 km radius). See, for instance, Nakamura, 2010; Shearer, 2010; Johnson, et al., 2005; Khan, et al., 2003. And if we can deploy newer seismographs (e.g, Murphy, et al., 2010) we will go all the way to the core, as we do for Earth. All of these papers can be downloaded as free PDF.
 
Last edited:
You must log in or register to reply here.

Share this page

ISF - Join now!

Every member here is approved by hand. No bots, no spam, just people who care about evidence and honest debate.

Membership is free!

Create your free account

Back
Top Bottom