SUPER MOON and The Daily TSUNAMI Tides of The Past
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| The SUPER MOON on 19 Mar 2011. |
view from London: [51°25’56”N,0°30’37”W]
With a good view of the most distinctive TYCHO impact crater,
(bottom-right) with 85km diameter and its 'impacts rays' on the surface
extending upto 1500km, in the "southern highlands" of the moon.
When enlarged, to original picture size, can see the uneven texture of the surface,
esp., crater-rims on the top edge/north.Also visible are the 'rays'/streaks from Copernicus and Kepler craters.
Taken with a 400mm lens, with 1.7x TeleConverter attached.
I was counting my lucky stars, as you don't get clear skies often here!
LUNAR FEATURES:
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Appollo11 landed close to where it is ponting for "Sea of Tranquility"(Mare Tranquillitatis in Latin) with Neil Armstrong's "One Small Step for Man, One Giant Leap for Mankind", |
The Near Side of the Moon- We can only see the near side from the earth, as..
The Moon is in synchronous rotation: it rotates about its axis in about the same time it takes to orbit the Earth. This results in it nearly always keeping the same face turned towards the Earth..
{The side of the Moon that faces Earth is called the near side, and the opposite side the far side. The far side is often called the "dark side," but in fact, it is illuminated as often as the near side: once per lunar day, during the new Moon phase we observe on Earth when the near side is dark.}
Have collated this interesting information from 3 different documentaries and also information mining from wiki.. and refined, melted and fused.. doing "forging" to create this artcile.. Hopefully doesn't sound like forgery;)
The gems of info obtained working in this word-smithy include :
- ---The tidal waves on rocks on the moon, (Long ago, used to rise and fall upto 7meters!..tidal waves on solid ground!. now, The lunar surface also experiences tides of amplitude ~10 cm )
- --- "Moonquakes" : The cumulative effects of stress built up by these tidal forces produces moonquakes. Moonquakes are much less common and weaker than earthquakes, although they can last for up to an hour – a significantly longer time than terrestrial earthquakes – because of the absence of water to damp out the seismic vibrations. The existence of moonquakes was an unexpected discovery from seismometers placed on the Moon by Apollo astronauts from 1969 through 1972.
- --- The real dynamics of earth and moon, their push and pull, their interplay..and o'crs, there's the sun lurking in the background pulling some strings and smirking.. that results in the need for sometimes adjusting clocks end of the year-- STOPPING TIME!! (because earth slows down).. this adjusting-time had puzzled me for many years.. Well, the concept of Time itself.. and Space-Time is still puzzling; Forget about Black Holes that can warp time, and space, they say!! ;))
- ---AND confirming again, that NOTHING is EVER permanent.. and CHANGE is the only Constant!.. ;)
Why The Moon Always Shows The Same Face to Us :
The following is the relevant transcript from this new BBC Documentary series, 'WONDERS OF THE UNIVERSE'.. Episode on 'GRAVITY' : It explains about an earlier faster-spinning moon slowing down to current level, such that it only has one spin during one rotation around earth..
Throughout human history, every human that has ever lived has gazed up at the moon and seen one face shining back at us. The reason why we never see the "dark side" of the moon, is all down to the subtlety with which Gravity operates..
Millions of years ago, the moon rotated rapidly (than it is now), but from the moment it was born, it felt the tug of gravity. Just as the moon creates great tides in our oceans, the earth also caused vast tides to sweep across the surface of the moon!.. but this tide wasn't in water.. It was in rock.. The earth's gravity acted on the moon and stretched it out in to a kind of rugby ball shape.. and the size of that tidal "bulge" facing the earth was something like 7meters!-- on Rocky surface!!.. and when the moon rotates, that "bulge" sweeps across the surface of the moon.. Imagine what it would look like.. a tidal wave sweeping across the landscape.. the solid surface rising and falling by 7meters!..
This massive land-wave acted like a 'brake' and gradually slowed the moon down.. Eventually the tidal bulge became aligned with the earth.., "locking" the speed of moon's rotation-- So the speed it takes for the moon to "spin once" {'lunar day'} is almost the same as the time it takes to orbit the earth. So, there is no "dark side" of the moon.. Just the side that Gravity hides from our view!!
The Daily Tidal Waves of the Past were worse than recent Tsunamis:
( Tsunami--japanese for harbor[tsu]-wave[nami] -- and tides both produce waves of water that move inland, but in the case of tsunami the inland movement of water is much greater and lasts for a longer period, giving the impression of an incredibly high tide. )
That part from the above documentary gives only one side of the story. There are other sides to the Earth-Moon story which was elaborated in another documentary that was broadcast in 2009, in its part explaining the Origin of the Earth and the Moon.
How The Moon was Born! :( Had watched this program on TV; This video of it on youtube is now blocked in UK due to copyright issue with the TV channel. But this--could be just a small clip from it-- might be accessible outside UK:
)
In its full version, they showed the simulations of early history of earth and moon, the theory which could be proved by computer simulations of the dynamics of a catastrophic collision : About 30-50million years after the solar system was formed.. around 4.5billion years ago..
After a Mars-sized planet crashed into what was proto-earth (with no life and water then), from the dust and debris of molten rocks thrown out in this violent event, the Moon was formed, spinning around and accumulating more mass/coalescing from the debris.. (in much the same process as how dust particles accumulate and settle down as weight increases, in closed rooms. )
Both Earth and Moon, fiery balls then, were spinning much faster and were closer. Faster-spinning meant that the days were much shorter.. At one time in distant history, a day lasted for just 10hrs on earth, but a year was of same duration as today to complete orbiting the sun: So in effect, a year had much more days than the current approximate 365.25.
Also, after water and life started on earth, there was a time when a year had about 400 days- The scientists confirmed this by finding its proof that could still be seen in some corals from many millions of years ago, which record accurate daily deposits of layers on it, with cycles of annual patterns on them.
During such times, the moon was so close to earth than the current average of 384,000km.. that the Lunar face appeared as such a huge looming disc in the horizon. So, (after everything on the surface had cooled down and later when the oceans were formed,) the moon would pull the oceans facing it to such an extent, that waves would form more than 100meters high!!.. (Comparing this to the recent tsunami waves of 10-15m high, it means, there were daily 'tidal Tsunamis' on earth!!, even though those huge tidal waves might not have travelled at huge velocities like those triggered from seismic shifts/undersea earthquakes) and this bulging ocean on earth facing the moon would also drag earth's rotation, gradually slowing down the earth's spin over millions of years, increasing the length of days.(currently @about 15 microseconds every year. That increase must have been much higher earlier)
At the same time, this gravity interplay between earth and moon also has the effect of pushing moon further away..
Angular momentum of earth decreasing due to the drag from 'tidal friction' of oceans bulging, and therefore..--ie, due to 'The conservation of angular momentum in Earth–Moon system'-- angular momentum of Moon increasing, accelerating it into slightly longer orbit..
Thus the moon has always been drifting away, even today (even though, currently at 3.8cm/year;). Laser reflecting mirrors are left on the moon during an Appollo mission, on which observatory from earth precisely focus and fire laser and measure the time it takes for the reflected beam to return, measuring distance to the moon at a particular point in its orbit.
For more details, Refer: http://en.wikipedia.org/wiki/Moon#Tidal_effects
http://en.wikipedia.org/wiki/
Tycho is a prominent lunar impact crater located in the southern lunar highlands, named after the Danish astronomer Tycho Brahe (1546-1601)
Tycho is a relatively young crater, with an estimated age of 108 million years (Ma), based on analysis of samples of the crater rays recovered during the Apollo 17 mission. This age suggests that the impactor may have been a member of the Baptistina familyof asteroids, but as the composition of the impactor is unknown this is currently conjecture. However, simulation studies give a 70 percent probability that the crater was created by a fragment from the same break-up that created asteroid 298 Baptistina;[1] a larger asteroid from the same family may have been the impactor responsible for creatingChicxulub Crater on Earth 65 million years ago (mya), and causing the extinction of the dinosaurs. (This ancient impact crater is now partly buried underneath the Yucatán Peninsula in Mexico, and partly on the sea-bed. Its center is located near the town of Chicxulub, after which the crater is named. The crater is more than 180 km in diameter, making the feature one of the largest confirmed impact structures on Earth; the impacting asteroid that formed the crater was at least 10 km in diameter. The impact would have caused some of the largest mega-tsunamis in Earth's history, reaching thousands of feet high. A cloud of super-heated dust, ash and steam would have spread from the crater, as the impactor burrowed underground in less than a second. Had seen another nice documentary recreating its fascinating story)
The crater is sharply defined, unlike older craters that have been degraded by subsequent impacts. The interior has a high albedo that is prominent when the Sun is overhead, and the crater is surrounded by a distinctive ray systemforming long spokes that reach as long as 1,500 kilometers. Sections of these rays can be observed even when Tycho is illuminated only by earthlight.
MOON TRIVIA:
the lowest summer temperatures in craters at the southern pole at 35 K (−238 °C),[77] and just 26 K close to the winter solstice in north polar Hermite Crater. This is the coldest temperature in the Solar System ever measured by a spacecraft, colder even than the surface of Pluto
More on SUPERMOON:
4. Will the moon ever be closer to our planet?
Yes and no. The moon is actually being "pushed" away from the Earth at a rate of 1.6 inches annually. Several billion years from now, astronomers predict that the moon's orbit around the Earth will take 47 days, rather than the current 27.3.
However, another more dramatic event could take place that would position the moon within a sky-filling 11,470 miles above the planet, termed the Roche limit. This would only happen if the sun mutated into a red giant, causing the moon's orbit to decay. Of course, life would cease to exist on the planet in this stage, so this "Mother of all Supermoons" would not be much of a concern.
NASA Article/ Q&A -SUPER MOON:
Science@NASA Video- -SUPER MOON:
posted by Sujith at 6:34 AM
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