Earth w/o Magnetosphere, w/o Moon

Lars Kecke wrote:
BruceS wrote:

Mark McIntyre wrote:


"There is a huge force of gravity between the earth and moon - some 70
million trillion pounds (that's 70 with another 18 zeroes after it), or
30,000 trillion tonnes (that's 30 with 15 zeroes)."


Euh, firstly gravity isn't measured in pounds or tonnes


Why would one not use pounds to measure a force?


An old unit of force indeed was Kiloponds (i.e. the force of one
kilogram of mass at normal gravity), which is kind of misleading in
regions that don't have standard gravity, e.g. the earth-moon system.

Anyway, the moon's centripetal force is of course GmM/r^2 and its
binding energy is about -1/2 gmM/r, with r being about 4*10^8 m and GmM
being about 3*10^37 Jm, iaW the moon's binding energy is a few thousend
yottajoules (had to look up that prefix, never used anything bigger then
exa- ).

Are we still conflating energy with force? Or is there another issue,
that some forces are measured in different units than others?

BruceS wrote:
Lars Kecke wrote:

Anyway, the moon's centripetal force is of course GmM/r^2 and its
binding energy is about -1/2 gmM/r, with r being about 4*10^8 m and
GmM being about 3*10^37 Jm, iaW the moon's binding energy is a few
thousend yottajoules (had to look up that prefix, never used anything
bigger then exa- ).

Are we still conflating energy with force?

Never did. I just don't use the concept of "force" much, at least for
closed systems like the earth-moon-system, that's why I went for the
binding energy; to get the force in Newtons, just divide by r/2. Btw,
what happened to my exponents in your reply?

Or is there another issue,
that some forces are measured in different units than others?

The SI unit of force is Newton, but sometimes it is more intuitive to
measure force (e.g. the thrust of a jet engine) in kiloponds (or pounds
of force for you anglophones).

Lars

"Lars Kecke" wrote in message


The SI unit of force is Newton, but sometimes it is more intuitive to
measure force (e.g. the thrust of a jet engine) in kiloponds (or pounds
of force for you anglophones).

So what? There's still 2e20 joules worth of gravity's energy, whereas
if just 0.1% of that force as energy gets applied to a given terrestrial
m2 is worth 391 joules.
-
Brad Guth


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Lars Kecke wrote:
BruceS wrote:

Lars Kecke wrote:


Anyway, the moon's centripetal force is of course GmM/r^2 and its
binding energy is about -1/2 gmM/r, with r being about 4*10^8 m and
GmM being about 3*10^37 Jm, iaW the moon's binding energy is a few
thousend yottajoules (had to look up that prefix, never used anything
bigger then exa- ).

Are we still conflating energy with force?


Never did. I just don't use the concept of "force" much, at least for
closed systems like the earth-moon-system, that's why I went for the
binding energy; to get the force in Newtons, just divide by r/2. Btw,
what happened to my exponents in your reply?

I don't know. They look the same in my reader (Mozilla) for your
original message, my reply, and your reply to that.

Or is there another issue, that some forces are measured in different
units than others?


The SI unit of force is Newton, but sometimes it is more intuitive to
measure force (e.g. the thrust of a jet engine) in kiloponds (or pounds
of force for you anglophones).

Thanks, that's what I thought. I was originally replying to a claim
that force wasn't measured in pounds. Apparently, that poster was mistaken.

"BruceS" wrote in message


Are we still conflating energy with force? Or is there another issue,
that some forces are measured in different units than others?

Are we still playing dumbfounded about the truth?

So what's the difference? Force is always equal to a given amount of
energy, as is energy equal to a given amount of force.

There's still 2e20 joules worth of gravity's ongoing energy that's
continually existing between us and our moon, whereas if just 0.1% of
that force gets reapplied as into a tidal force of causing unavoidable
friction, and if that were shared with each and every given terrestrial
m2 is worth 391 joules/m2.

Therefore, even 0.01% of 2e20 j, as if that were applied to the entire
surface area of Earth (including that of it's mantle and upper mantle)
is still per total surface area worth 39 j/m2, and that's continuous
throughout each and every second of each and every day from the very
beginning of our moon's arrival, though I'm not even including
whatever's the initial worth of the moon/Earth impact transfer of
energy, which should have been damn impressive.

How can there not be a direct thermal energy association with whatever's
being kept in motion by way of that orbiting mascon of a moon?
-
Brad Guth


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