Expert: Jayendra Upadhye - 6/7/2008

Question
QUESTION: Hi Jayendra again. I realise that the Earth's rotation is slowed by the moon as it pulls the body of water which crashes into the rotating (upcoming) coastline. This resulting extra pull on the moon is accelerating it into a higher orbit. I was wondering if the pull might just be elongating the mass of the moon and the acceleration(to a higher orbit) might be caused by something else?. The moon has lava flows on the face that we see and the far side has more crater impacts, this suggests the Earth has tidally heated the moon at some point(this may be still going on)which is why the lava flows are on one side.

ANSWER: Hi,
Robert, I believe that it could be just a case of being on the "rain-shadow" of the earth (metaphorically imply that incoming meteors constitute a rain), as one side constantly points earthwards.

The phase locking implicitly protects "that face" of the moon from any meteors coming in along the line of sight connecting the earth moon centers. The earth being larger in cross section, will obviously stop most meteorites coming moonwards "along that direction" which is collinear with the eart-moon-axis.

Thus that face of the moon is shielded effectively from meteorite impacts!
Leaving the lunar maria (ancient lava flows) intact more or less.

The other side has no such shield for meteors coming from the other side! Hence more cratering on that side.

In fact if the statistical average rate of cratering of the moon is known (it varied over epochs, reaching a maximum in the late bombardment phase of the evolving solar system), we can predict when the maria formed, and when the moon got phase locked!

Lastly tidal heating is NEVER a localised phenomenon, as it is too gentle comparatively, to remain "localised". It quickly is absorbed by the centralised areas uniformely over eons, and STOPS once phase locking is complete! (As there is no more a travelling bulge on the phase locked body, but a rather permanent oblateness along the joining axis of the two bodies.

The maria are in all likely hood a hangover from the late bombardment phase more than a billion years ago.

Secondly, a convecting fluid core would inevitably give the moon a magnetic field and its own van allen belts! And polar aurorae Boralis!! Does it have them? Jupiter has!

Venus too if i am not mistaken and so does mercury if i remember right.

regards
Jayen



---------- FOLLOW-UP ----------

QUESTION: But do you think the expanding orbit could be due to something other than the pull of the Earth's Oceans? The pioneer anomaly suggests planetary orbits in the solar system are expanding compared to the pioneer craft(or are the planetary orbits perfect and the pioneer craft is accelerating towards the Sun)? Is the moon's expanding orbit unique or is expansion normal. The universe is expanding after all.

ANSWER: Hi,
No robert, the moon's recession is in tune with calulated slowing down of the earth as measured accurately by the caesiun atomic clock of the national physical laboratory (?) (i may have got the name of the isntitution wrong, check it out).
The nation's time keeper in the USA keeps track of time using atomic clocks. These clocks have to resynchronise themselves as the day lengthens due to the slowdown of the earth.
That slowdown is in tune with calculations regarding recession rate of the moon, now accurately measured by laser ranging.
It has NOTHING to do with the expanding universe. The hubbles constant applies to very large distances comparatively. (Parsec level).

hope that suffices.

Robert it is one thing to have pet theories, but doubting well calculated stuff and searching for "other theories" is counterproductive. That would be like searching for hyperatomic drives onboard steam engines running on a rusty ancient railtrack.

Do rate the answer if you arent too cross at me for "talking down to you"!! :)

Robert after so much interaction..i am going to say something..
i am on thin ice here, and talking on assumed seniority and authority for i do not know your age. But you seem to be from the college going lot.

And i feel you seem to be having a problem here.
Some how i sense a sort of "unhappiness with something"..some unresolved stuff..

tick me off if i am wrong. and use my advice if i am right!

I hope you are not a closet "bible" guy..
i have had some cases in the past where they end up questioning everything about science and never question their own stand at all!!
all one way stuff.

I am saying all this because i think you are sharp and need to be warned that incessant questioning "for the heck of it" or due to some other unresolved underlying conflict (questioning authority / rebellion) will only slow your progress. The world wont care two hoots about us both mind you.

So shape up.
Good luck.
regards
jayen


---------- FOLLOW-UP ----------

QUESTION: Re the slowdown of the Earth's rotation is in tune with the expanding orbit of the moon. I think the rotation of the Earth slows by 1 second a century (but please correct If I am wrong) and the moon's orbit increases by 3.8cm a year. Is there a formula or theory that predicts this correlation or has the correlation been made because of these measurements?

Answer
Robert!!
1 - You are "a seeker"! Period.
   And thus who am i from stopping you from questioning?
   Proceed and pester me as long as you like!
   And most welcome!!
   I like interacting with guys like you.
   I was "similar" when i was in college.
   That's why i thought you were a college going guy too.
   If you are 39 and asking these questions then i can conclude
   a) - You are a late beginner. (decided to persue this at leisure
        "when you had more time on hand".
   b) - You have courage and are willing to be lectured by stupid
        guys like me, if that "gets you what you want.
   Both likeable qualities in a true seeker.

2 - It is all about 'conservation of angular momentum'.
   The maths involved, and the principles involved, both are as old
   as newton's pricipia!
   I am a bit surprised you did not know.
   Hence i called you a late beginner.
   Robert, you need to read up a lot, catch up a lot, brush up a lot.
   A lot of catching up to do, before you can start asking the
   really serious questions.
   Till then, you have to convince yourself to "recieve the accepted
   gospel" hook line and sinker!
   After all we all learn our ABC and multiplication tables "without
   question" if we are to get ahead and do anything at all in life
   dont we?

3 - The standard approach to questioning a theory is the trojan
   approach! (after all a mighty city fell due to that).
   Get into it first, feel at home there, then start the plundering.
   So it is that HIV does to us, So it is that we must do to any
   theory we need to question.

   In my language there is a saying "shake the foundations to make
   them strionger".

   That is a TRUISM.

regards
Jayen