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NASA Details Earthquake Effects on the Earth
Cuyamaca writes "
NASA
scientists, using data from the Indonesian earthquake
calculated it affected Earth's rotation, decreased the
length of day, slightly changed the planet's shape, and
shifted the North Pole by centimeters. The earthquake that
created the huge tsunami also changed the Earth's rotation." You now have 2.68 fewer microseconds each day to do whatever it is you do.
neat
Let me guess, those are missing in the night, right?
At least that would explain my lack of sleep lately...
Too small to detect? Then why is my watch running slow?
Seriously, this means we'll need an additional leap second once every thousand years or so. Unless, of course, something else changes the length of the day, which will likely happen first.
How am I supposed to fit a pithy, relevant quote into 120 characters?
" You now have 2.68 fewer microseconds each day to do whatever it is you do. "
Oh well, I probably would have wasted it anyway.
Bartender, another Fort Garry Dark, and hurry!
Trolling is a art,
You now have 2.68 fewer microseconds each day to do whatever it is you do.
;)
Damn! My project is already behind schedule, this is the last thing I need. Oh well, better stop reading so much slashdot
-dynamo
Ack - there's already not enough time in my day, and now it's shorter!
great, more time for people to do things like this
/* No Comment */
Now how am I supposed to find the time to get all those TPS reports done!
Here a Sig There a Sig Everywhere a Sig Sig...
Will the changes in Earth's rotation affect it as well?
Execute? [Y/N] _
as if anybody will tell the difference in real life.
r0flc0pter
What's the effect on GPS? Large enough to need compensating for?
Shucks, that's one less masturbation each day :(
Natherlands can't grow as fast. I can't study geography as much.:(
You now have 2.68 fewer microseconds each day to do whatever it is you do.
Well, there goes my sex life.
calculated it affected Earth's rotation, decreased the length of day
Does this mean that NASA confirms that superman can indeed turn back time?
----
Squirrel
You now have 2.68 fewer microseconds each day to do whatever it is you do.
Yay! My first raise in pay since 2001!!
"If you think you have things under control, you're not going fast enough." --Mario Andretti
Is this change big enough to update the atomic clocks? I think this quake really puts things into perspective - the Earth (and "24 hours in a day") isn't as set in stone as people think it is. (Pun intended?) And who knew the poles could move?
If you're not outraged, you're not paying attention!
NASA scientists, using data from the Indonesian earthquake calculated it affected Earth's rotation, decreased the length of day, slightly changed the planet's shape, and shifted the North Pole by centimeters. The earthquake that created the huge tsunami also changed the Earth's rotation.
What exactly do you editors do besides add pointless side comments? Evidently not editing.
Your hair look like poop, Bob! - Wanker.
Wow, the Tsunami increased my life expectancy by 50,713.6 microseconds.
~~~
Click here, you know you wanna!
You now have 2.68 fewer microseconds each day to do whatever it is you do.
And I though sex couldn't get shorter...
You now have 2.68 fewer microseconds each day
That's several thousand CPU cycles on today's chips, and even more cycles for future chips. These cycle-stealing earthquakes must be stopped! STOP PLATE TECTONICS!
Intel transfer the difficult from Hadware to software, for get more power, programmer need more technology. -- chinaitn
According to this article the moon's orbit is causing our day to lengthen by about 2 milliseconds per century anyway. I, for one, am greatly relieved. ;-)
Angular momentum is conserved and is calculated by L = Iw where I is the rotational inertia, w is the angular velocity and L is the constant product. So if I goes up (and I will show in a minute how that happens), w must go down. I, the rotational inertia, is calculated different ways for different geometries. A long stick held by the end has a larger I than the same stick held by the center, for instance. Another example is a sphere, like the Earth, rotating on an axis. If it suddenly puts out a long arm, that's going to increase its rotation inertia considerably, decreasing its angular velocity. Lifting up a whole region by a few inches could easily do that.
It seems to me that changes like this could have a dramatic impact on global climate. I've recently been accused of dropping flamebait before, and that's not my intent, but doesn't it seem that if the earth can just "adjust" like that, and kill hundreds of thousands of people (impacting millions) that it's possible that global warming might be just another natural adjustment? Or wait... did emissions cause the earthquake...? hmmm....
Damn, no wonder I'm feeling so tired lately
I like this quote, which underscores the lack of newsworthiness of this, "Any worldly event that involves the movement of mass affects the Earth's rotation, from seasonal weather down to driving a car." So, using that fancy scientific notation to represent all the zeroes between my numbers and the decimal point, I can compute the change in rotation and pole location caused by my commute this morning. Call the newspapers!!!
"I don't know half of you half as well as I should like, and I like less than half of you half as well as you deserve."
to do nothing, but at least this year I'm doing nothing 2.68 microseconds less per day. Critics back off.
Hit the wrong damn key. The subject was supposed to be "Won't matter". Who put that apostrophe so close to the 'enter' key?
A CNN article on this subject included what I thought was a fascinating quote:
In human time, earthquakes that powerful are rare, but in the vastness of geologic time, they are commonplace. "An earthquake of this magnitude, in this part of the world, has probably occurred about a million times since the breakup of Pangea," said Chris Scotese, a geophysicist at the University of Texas-Arlington. "No exaggeration."
Too often we're bounded by thinking of events in human time scales (if not generational time scales) but a 9.0 quake is just a regular occurance in the life of the Earth. It's suppose it's events like these that reveals how insignificant we are in the grand scheme of things.
Well they do have daily 2.68 usec loss to deal with you know. Ease up man.
BSD is designed. Linux is grown. C++ libs
Just great, now our stupid Bush will pull the wool over peoples eyes and have a damn good excuse to waste billions MORE of out tax dollars towards space exploration so we can expedite our move to Mars.
Since the days are shorter now does that mean my life expectancy has increased?
So did I
"You're older than you've ever been, and now you're even older."
What about long term effects? With all the abuse we throw at planet Earth and now this...
The polar ice caps melts slightly more... water level rises... gravity changes that little bit...
That could eliminate sex entirely for some guys.
Oh no! I already lived these 2.68 microseconds!
Dashboard Widgets
I read on CNN science page that scientists normally look for big events like these (quakes measuring more than 9) in order to learn more about earthquakes. However it was extremely difficult to learn anything as most of the fault lines are deeply buried in ocean bed. Other theory is that these kind of pheneomenon was what resulted in formation of all the continents as we see today from a big land mass lump called Pangea which existed millions of years ago. Another theory is now that these continents are on move again getting closer to forming a big lump. Australia is on a collision course with Asia and North America with Europe. Africa is pushing up on Europse and reducing the Mediterranean region. Considering the technological knowledge this is really neat however considering human lives this is very very sad incident.
You now have 2.68 fewer microseconds each day to do whatever it is you do
Oddly enough, this is the exact length of a 30 minute sitcom minus commercials... I wonder which show this will force off the air?
--
Was it the sheep climbing onto the altar, or the cattle lowing to be slain,
or the Son of God hanging dead and bloodied on a cross that told me this was a world condemned, but loved and bought with blood.
...thats a little less time to finish my final-year degree project. Wonder if I have grounds for an extension...?
It is very common. For example, the duration of the day in summer is longer than in winter (no, I'm not speaking of the length of the light period, but of the rotation period of the earth). The reason is that the trees move mass upward in spring (they get leaves) and downwards in autumn (the leaves fall back down), which changes the moment of inertia of the earth. Since trees only grow on land areas, and most land areas are on the Northern hemisphere, this gives a net effect of slower earth rotation in (Northern) summer.
The Tao of math: The numbers you can count are not the real numbers.
Thank god they finally gave us the "each day" part... this was posted earlier on /.
While the day may have gotten shorter, the orbital period of the Earth didn't change, so you get the time back over the entire millennium as an extra leap-second.
Well, technically you heard it two weeks - (14 x 2.68 micro seconds) ago.
I always thought it was 24 hours. Is it now 24 hours - 2.68 microseconds, or has it ALWAYS been very close to, but not exactly 24 hours?
Unlikely. Earth's mass remains the same, so the orbit around the sun is unaltered.
. . the grass was greener, kids were polite to their elders and the day was longer!
An earthquake can influence the rotation speed (by affecting the way the Earth's mass is distibuted around the rotation axis), but they cannot affect the revolution speed.
Someone please help me out here. If we lost time in our day, that would mean the Earth is spinning faster. I thought that the faster an object moves, the slower time goes. So wouldn't this sort of cancel everything out in the long run?
"I don't need drugs to enjoy this, just to enhance it" - Otto
Redundant? How-so...this guy/gal at least compared the time lost to someting relavent as opposed to others.
what?
i heard this two weeks ago...
I think the news here is that they've actually done the calculations. They knew it would change two weeks ago, but not what the final number would be. Slate's "Explainer" had an article on scientists' expectations of this right after the quake.
One man's -1 Flamebait is another man's +5 Funny.
I've submitted a kernel patch to adjust the 'gettimeofday' POSIX function to account for this 2.68 microseconds. Most of you wont notice a difference, but for real-time applications, this can be a significant interval. We probably need to add some additional 'daylight savings' flag adjustments for applications that do / don't want this adjustments.
Oh, shit, I dropped a CD to the floor, can someone calculate how that affects Earth rotation? Yes, it's a big event, but it is so much smaller than (EG) this: http://en.wikipedia.org/wiki/Krakatoa. I read that they was tracking climate changes caused by this in _Europe_ 5 years after the event.
Where the fuck do kids learn this shit? Sorry to go off on you, but we get posts like yours every time any thread comes up involving "the earth".
This ball of rock has been here for 4.5 billion years. It ain't going nowhere it ain't gone for the past 4.5 billion years.
Conservation of angular momentum is not the same as conservation of mass. You can speed up the Earth's rotation by squeezing it into something shaped like a bowling pin, or you slow down its rotation by squashing it into a disc, but its orbit around the sun doesn't change unless you add mass to it. And that isn't going to change measurably unless you add so much mass that all life on it would be wiped out anyways. (Hint: We've been taking on a few tons of mass every day in the form of micrometeorites. OMGLOLZ TEH SUN GONNA EAT US... well, actually, not. The earth is a small planet, but it's still pretty fucking massive.)
The reason I'm going ballistic is that this is all basic physics that was figured out over 300 years ago. It's called science. If you're not learning it in school, walk up to your envirocuddly studies, creationist esteem, or whatever the fuck else bullshit they're teaching today teacher. When you're within three feet of that teacher, give him or her a royal bitchslap. They'll expel you. That means you can get out of the fuckin' schools and into a fuckin' library and start learning something.
Yippee, that raises the average human lifespan.. right?
For crying out loud, now I can forget about that morning coffee.
Anyway, I think thats pretty serious thing to happened. Now that we know, from the past observation, that polarity of pols is changing, that earthquake might have sped it up and hmm The Day After Tomorrow will come sooner than previously thought.
I needed those microseconds to attend to my personal needs....
Ok, so if the Earth is rotating faster, and it's mass stays the same, then the Earth-ward force should be reduced. The faster the planet spins, the more intertia I have. The more inertia I have pulling me away from the planet, the less the effects of gravity (acting as a centripital force) would be felt.
Am I missing anything, or do I weigh a fraction of a fraction of a pound less?
~D
This sig has been enciphered with a one-time pad. It could say almost anything.
Like how many of these earthquakes have happened? What's THEIR contribution to altering the Earth's rotation?
Assuming that these earthquakes are completely random, and have a more or less uniform distribution (well, actually around the limits of the tectonic plaques), I assume that in average the earth will have the same rotation speed. Some earthquakes will accelerate it, others will slow it down.
This earthquake just happened to be the first one whose effects could be MEASURED. First sample, doh?
Frankly this "oh wow look! the earthquake was so powerful it affected the rotation speed of the Earth!" stuff makes me laugh.
Does faster spinning earth have any effect on its orbital speed? I should have paid attention to all that angular motion stuff in physics class!
Then again, I wish I had that much free time on my hands. OK which one of the guys is gonna re-adjust all those atomic clocks :P.
Doesn't matter if the Earth's mass changes. Only the Sun's mass affects our orbit.
"Studies have shown that people who eat peanuts live longer than those who do not eat."
I had to answer a question from someone who'd heard that our days were now 2 seconds shorter.
On top of that, the numbers are based on a model, not measurements. The length of a day can't even be measured to better accuracy than 20 microseconds.
And then there's the fact that the natural tendency of the planet is to slow its rotation due to tidal drag. You should get back your 3 microseconds within a reasonable time.
Welcome back! This news is at least 2 weeks old.
You're moving this completely offtopic anyway, so...
Who cares WHAT causes global warming?
If the earth warms up by a few degrees and millions of people end up starving to death due to the floods and loss of farmland and other havoc then this is a bad thing.
And unlike tsunamis, we have the technology and the ability to reasonably reduce the risk of this happening.
This idea first popped up in sci.geo.earthquakes shortly after the quake. At the time I figured that for the earth to slow down, the mass would have to move away from the earth's center to lower its angular momentum. The question that raised was "how do you measure a mass shift like that?" The TOPEX data aren't that precise as they're limited to around an inch or so of resolution and require multiple passes to get that accurate. The Grace data are even less precise. An alternative would be to be continually measuring the earth's rotation using an atomic clock and notice a sudden shift the day of the quake. Or maybe someone noticed some anomaly in the GPS network. Whether any of these methods, or some other methods, were employed the article doesn't say.
It's typical NASA self promotion with no substance.
First, I believe the Sun and Moon perturb the Earth's rotations at perigee and appogee in terms of miliseconds. Wouldn't the effect of these two bodies "wash" the any microsecond change in the rotation of Earth?
Second, what about the conservation of energy? If the angular moment of Earth changed (according to the article earth speed up) where did the energy come from? For the Earth to speed up, energy has to be added to the angular moment of Earth. Even if a chunk of the Earth's mass shifted somewhere the energy is still conserved because it came from somewhere else.
Everything on Earth is still on Earth although with a quake this big they aren't in the same places. Where did the extra energy come from to speed up the planet? Moving things around on Earth does not change the angular momentum of the planet.
You now have 2.68 fewer microseconds each day to do whatever it is you do.
.0000804 frames/second to the human eye. A pretty useless BIOS tweak.
In gaming terms: This is a difference of about
Best...troll...ever!
Try not to forget - that wave propagated in all directions. It's origin was ~800km down, and it went toward the center of the planet through a much denser medium than water. The tsunami was a droplet on the surface.
kulakovich
FWIW I have a PhD in physics. One thing I learned is how to spot pseudo-science the one for the plebs to chew on. This is one of those. They plugged some numbers in some equations, so booyah. What's the error on those? How accurate is it?
Note how they back off and say that none of the predictions are actually verifiable ... heh
False. The gravitational pull of the earth attracts additional matter from space on a constant basis, so its mass is *always* increasing, even if the increase is barely measurable and totally imperceptible.
Self-referential sigs are rarely entertaining.
if you consider that in Devonian period (375 million years ago) days were about 22 hours long and the year had 400 days (Since the length of a day increases by 0.002 seconds per century).
The rate of slowing down is actually decreasing as moon moves away from Earth ( 4 cm per year ).
How does GPS play into this if the rotation is changing, I know it's by a little but wouldn't that still play into government missiles and stuff for guidance. I watch too much Discover channel forgive me in advance. :P
Stan M. ~~~Verbal~~~
If the earth is spinning faster, then we in turn are spinning faster as well. According to Centripital forces, we would then be a little lighter as well. So much for my new year's resolution to lose weight :)
Atrivis
That's all we need, just one more little bite out of my day. Pretty soon it's going to be go to work - then straight to bed. There should be a government program to build massive structures near the equator to lengthen the day so we can have more free time. Or perhaps they should crack the earth's core along the equator and to make some nice big volcano's there. Sort of killing two birds with one stone, increase the length of the day and expand the amount of usable land on the planet. Sure it would take most of our nuclear arsenal, kill off massive amounts of sea life and quite possibly cause a disaster the scale of which humankind has never seen. But I want my 2.68 microseconds damn it!
Wow, talk about screwed up thinking.
It's precisely because of conservation of angular momentum that the rotation has increased! Angular momentum must stay constant. The radius of earth has decreased slightly. Thus, in order for the angular momentum to remain the same, the rotation must speed up slightly.
Angular momentum is not the same as rate of rotation. NOT THE SAME!
And this info just consumed a valuable portion of
that.
No. By changing the Moment of Inertia of an object, and conserving angular momentum, the effect is to change the angular velocity of an object. Watch a figure skater begin a spin with arms outstretched, and then bring their arms in to their sides. Their rotational speed definitely increases despite the friction with the ice.
In this case, redistributing the earth's surface will it's moment of inertia.
IANAP (not a physicist), but I've noticed that when an ice skater spins and pulls in their arms, they spin faster. If the earth's overall density increases because a tectonic plate slides toward the center, then the Earth could presumably spin faster too.
Perhaps it's a question of a shift in the ratio between potential energy and kinetic energy.
i think i read somewhere before that the earth is slowly decreasing the rate of it's rotation, thereby giving us longer days.. so by decreasing the amount of time each day, does that mean that the earthquake has effectively sped up earth's rotation?
Welcome our new Day-Shortening, Rotation-Altering, Pole-Shifting, Chaos-Ensuing Overlords! (start bowing people, we don't want to lose another 155,000+ do we?)
Other theory is that these kind of pheneomenon was what resulted in formation of all the continents as we see today from a big land mass lump called Pangea which existed millions of years ago Any name for the new clump of lumps?
Nah, a troll that failed can't be successful per defintion ;)
Wow.
You just did. :-)
Sadly no one has noticed...
But the Jokes on you. Your boss has only been paying you for 39:59:59.999900.0
I always new that science would find a way to increase my lifespan. I will no live to be... 2.68us*365days*50years=4 hundredths of a second older than expected!
Thank you NASA and thank you US space program for making all this possible.
www.eissq.com/BandP.html Ball and Plate System. Amuse your friends. Crush your enemies.
Your working 2.68 microseconds less each day, but getting paid the same, so technically you got a raise! (provided you distribute thos 2.68 microseconds evenly among the hours your working and not playing WoW)
Yes Francis, the world has gone crazy.
What about the effects on the earth's rotation, didn't NASA scientists find anything on that? And I also read that the earth's rotation was affected, as well as the rotation of the earth.
I'm afraid you're going to have to come in Saturday.
"There is more worth loving than we have strength to love." - Brian Jay Stanley
Huh? I-- I don't know that! Auuuuuuuugh!
Ben Hocking
Need a professional organizer?
See, the reason the Earth is moving slower is because the average equatorial bulge grew a tiny bit, thus slightly reducing the gravitational attraction for those living on the equator. Therefore, due to general relativity, time will now move a little faster due to local weaking of the gravitational field except that this is exactly canceled out by time moving a little slower due to SR affects caused by moving a tad faster. (OK, I made up the exactly canceling out bit - but it might be true! And, I also made up the equatorial bulge bit, too. OK, I totally didn't RTFA, and am really just making most of this up.)
Ben Hocking
Need a professional organizer?
There's no dark side of the moon really. Matter of fact it's all dark. ;)
503 Sig Unavailable
The Signature could not be accessed. Please try again later or contact the administrator
I thought the mid-ocean ridge in the Atlantic was pushing North America away from Europe...
No. The law of conservation of angular momentum means that the angular momentum remains constant. The earthquake happened on earth, so no external torque was applied to the earth. The earth's rotation has sped up -- angular velocity has increased because the its effective radius has decreased, so the angular momentum is the same as before.
that explains why i lost the race.hmm
El Nino effect causes oscillatory changes of a few milli-seconds in the Earth's rotation (I believe it has to do with the sea level near the equator).
I bet you didn't notice that, did you? If not, then, don't worry about it.
This millisecond change in the earth's rotation is still conjecture, not fact. JPL fed some data into a model and theorized that there was a change in the rotation of the earth. But the troubling part is that, as they state, it is not measurable. So if we cannot prove that this is in fact true - then it is still a hypothesis - not a scientific truth. Has anybody heard of anything that can lend some creedence to it, such as GPS variations? Those who live by the scientific method....
I honestly don't know, but I am curious.
Hmm, I guess it does. A bit of looking at the Straight Dope reveals:
Dear Cecil:
Is the earth getting heavier or lighter? After all, we've littered the cosmos with a lot of NASA stuff, which should shave off a few pounds, along with vapor escaping from the atmosphere. On the other hand, there's a lot more people and meteorites around than there was in 8011 BC. What do you think? --Edward M. Smith Jr., Los Angeles
Dear Edward: Puny humanoid, you think the pitiful efforts of mankind have appreciably altered the mass of the earth, reliably estimated at 6 sextillion, 588 quintillion tons? (And man, if you don't think it was a bitch getting that puppy on the scale...) If so, shed your illusions. It's believed the earth gains anywhere from several dozen to several hundred tons per day due to meteorites and meteoritic dust--10,000 to 100,000 tons a year. (Sorry, but estimates vary widely.) This far exceeds any losses. The weight of the people, incidentally, has increased the mass of the earth by zero, for the obvious reason that we are but dust, and unto dust we shall return. To put it another way, human cells are merely rearrangements of the compunds previously found (i.e., before dinner time) in plant cells and animal cells. Net change pound-wise, nada.
The mass is still the same. The last time I checked the mass of Earth did not change reguardless of shape:
L = r x p
L is the angular momentum; r is the radius; p is the point measured.
Take something from one side of a planet and put it another the other. Angular moment has stayed the same so where is the speedup? Moving stuff around on earth does not change the angular momentum. Earth can speed up if you either "add energy" or "remove stuff" from the closed system.
Since it appears all of the stuff on Earth is still on Earth, where did the extra energy come from? Or did pieces of Earth disappear during the quake?
Explain the proverbial ice skater who speeds up her spin as she pulls her arms toward her body. According to you, this can only explained by "adding energy" (what energy?) or "removing stuff" (she lost mass?!)
For some bizarre reasons you seem to think that the r in L=r x p is a constant. It isn't. The earth contracted somewhat after the earthquake, bringing mass closer to the center of rotation and decreasing the moment of inertia.
Your understanding of this stuff is very incomplete.
Spend it on slashdo-
Thank you, thank you.
The internet is already plagued with lots of conspiracies and related sites that claim that the rotation of Earth has changed, a polar shift is imminent, the moon is in weird positions, the inclination of Earth has changed, the wobble of Earth has increased...there are much heated 'debates' all around about this stuff. And now this comes from NASA! it is a 'dream come true' for many conspiratorists.
I wonder how much are these conspiracies believed by the 'average Joe'? if the scientific knowledge can not reach the masses due to the flooding by stupidity...em conspiracy claims, then NASA, any other major scientific organization and generally science is in big trouble.
Maybe someone can explain this to me. If the days are shorter, but our bodies still age the same, does that mean our age at death will be higher than before?
If so, maybe ancient man lived shorter lives than us not just because of poor medicine, etc., but because the days were actually LONGER 50,000 years ago?
Would appreciate any feedback.
i read somewhere that the moon slows the earth rotation by 15 microseconds a year so whats the difference
If you are lighter, you have lost weight. But I wonder which is larger, the decrease in weight due to increase in centripetal force, or the increase in weight due to the decrease in average radius of the earth?
If you are not allowed to question your government then the government has answered your question.
see /.
The Earthquake was caused by an asteroid (meteor? distinction is unclear to me) hitting the Earth. So actually, the asteroid bumped us back. How could an Earthquake possibly do such a thing?
Does this mean every couple of hundreds of thousands of years we get to have a leap-hour?
FLR
...but does it explain where the dolphins went?
The Earth's mass does affect it's orbit around the Sun. See Kepler's laws of planetary motion.
Mea navis aericumbens anguillis abundat
This is not a significant change.
Oops. it's time change per day, not year. So it would be every ... couple thousand years or so? Sorry.
The following sentence is true. The preceding sentence was false.
The gravitational pull of the earth attracts additional matter from space on a constant basis, so its mass is *always* increasing, even if the increase is barely measurable and totally imperceptible.
The mass of all the space junk we've been throwing up there probably offsets that and then some, at least until the next asteroid hits us.
Look on the bright side:
The average male human lifespan just jumped from 72 years to 72 years and 0.6 seconds!
Punctanym: alternate spelling of words using punctuation or numerals in place of some or all of its letters; see 'leet'
Only try to realize the truth... There is no sitcom.
Required reading for internet skeptics
The annual variation in length-of-day is about two milliseconds. This is mainly due to seasonal changes in ocean currents and major storms.
If a equatorial bulge occurred, it would cause reduced gravity, and this would cause a relative increase in the rate that time passes for someone at the equator versus an outside observer. (That is, time would still pass slower for the person at the equator than for someone in a flatter spacetime - but not as slow as it did before the equatorial bulge.)
Ben Hocking
Need a professional organizer?
That's not correct.
You can prove it algebraically: Taking the simple case of a circular orbit, let r = orbital radius, M = mass of sun, m = mass of earth, G = gravitational constant, F = attractive force between sun and earth due to gravity, v = instantaneous linear velocity of earth
From Newton's law of gravitation, F = GMm/r^2
Since the orbit describes a circular path and no other forces act on the Earth, the centripetal force acting on it must be F. (Any object moving in a circle requires a centripetal force acting towards the center of the circle)
Centripetal force F = mv^2 / r
Since the forces are the same, equate them:
mv^2/r = GMm/r^2
Multiply both sides by r:
mv^2 = GMm/r
Divide both sides by m
v^2 = GM/r
As you can see, the orbital radius depends only on the Sun's mass (M) and the instantaneous velocity (v) since G is a universal constant. It is unaffected by the mass of the Earth.
The maths is a bit trickier for an elliptical orbit but the 'm's still cancel.
It is worth noting that in practice the Sun experiences the same force and is therefore displaced, but only by a tiny amount because it has a much greater mass than the Earth. I'm not sure if this is measurable but it has very little to do with the Earth's orbit.
"Studies have shown that people who eat peanuts live longer than those who do not eat."
They also study changes in polar motion that is shifting the North Pole. The "mean North pole" was shifted by about 2.5 centimeters (1 inch) in the direction of 145 degrees East Longitude. This shift east is continuing a long-term seismic trend identified in previous studies.
" So there is a real chance to claim first dibs on the new North Pole. Someone will have to tell Saint Nick about the fact that he will have to move! I wonder if the South Pole has a similar opportunity waiting.
If the earth's rotation slowed...doesn't that mean we have *more* time each day? What am I missing here?
If the earths rotation slowed, doesn't that mean we have *more* time each day? I, for one, welcome our rotation changing overlords.
2) We're that much closer to doing without Feb. 29.
"Any worldly event that involves the movement of mass affects the Earth's rotation, from seasonal weather down to driving a car," Chao said.
I wonder if we could all drive West (or would it be east) for 2.68 microseconds at the same time to counter the change.
*shrug*
It wasn't from this article, and I can't find it currently, but I read today that projects like the 3 Gorges Dam in China can have a similar effect on the earth... changing the placement of so much mass stretches and twists the earth, if only a bit.
So, the question is, how are megaprojects like this altering the earth? The dam, IIRC, is supposed to shift the North Pole another centimetre... which has to add stress to parts of the globe that don't expect it. Really, when you consider how little (relatively) stops tectonic plates from sliding under/over each other, or shifting laterally... is it wise to add another few hundred million tonnes to the equation? Sure, it's not much compared to the weight of the plate itself, but the phrase "straw that broke the camels back" exists for a reason.
If I knew the wedgies I gave you back in 6th grade would have resulted in this . . . I might have taken a moments pause.
... just increased by some .06 seconds or so?
The time aboard GPS satellites has to be measured with extreme precision, to the microsecond, in order to compute positions accurately. Typically they have to compensate for the time shift of about 38.7 microsecond/day (time is faster on satellites than on the ground) to account for the two theories of relativity, special and general. This amounts to about 1.16 millisecond/month. Given that the satellite speed is about 3.9km/s, this leads to a position shift of 4.5 meters/month that has to be corrected for accurate positioning.
Now the variation of earth rotational speed following the earthquake is 2,68 microsecond/day, i.e. about 7% of the relativistic shift, that is about 3.7 meters/year for the satellite position. I would suspect this is important enough to require correction. I do not know whether any provision was made in the programming of the satellites for such a change in earth rotational speed. Someone can answer that?
Another effect, for which I have no data, nor the ability to compute anything on short notice, is the slight change of the rotation axis. I have no idea of the kind of discrepancy it causes in the trajectory of satellites with respect to ground and the kind of correction it requires.
According to Dr. Issac Asimov in his book Astronomy the Earth and the Moon are a double planet in that they bot orbit the Sun.
They dance around each other as they orbit the Sun and the Moon always moves forward.
So I am not sure that the orbit of the Moon will change due to microsecond deviation of the rotation of the Earth.
Yea, but you will now live longer!
2.68 ms*[number of days you have left to live]=[how much time you've gained in your life thanks to the earthquake]
Not sure how long you have left to live, visit the death clock to find out.
Apparently I have 49 years left to live, so
2.68ms*49yrs= 131.32 ms added to my life, yay!
It's like it took the life from those killed and gave it to everybody else.
The only thing it would accomplish is massive world-wide destruction, earthquakes (worse the the one he was going back to stop), volcanos, tornados, cats sleeping with dogs, geeks getting the RDA of Vitamin D from actual sunlight, women standing screaming on chairs like in early sixties sitcoms. Come on people... this is not what the ol' Blue Red and Yellow stands for.
What we saw in the movie was just a visual representation of the Man of Steel himself traveling back in time. for some reason his succesful stoppage of the second big honkin missile wound up on the cutting room floor.
Re-read parent post in full for solution to conundrum.
p is not a point in space. It's a vector quantitiy consisting of mass times velocity observed at radius r (also a vector quantity) from the axis of symmetry.
L = rp sin(theta)
In this particular case, the trig function cancels itself out because we take the measurement at the equator, directly perpendicular to the axis of symmetry, and sin(90deg) = 1. Careful never to forget that you're dealing with vectors, though.
Since p = mv, the magnitudes of a planet's rotation at the equator are defined by the equation L = r x mv
The earthquake decreased r, and since m cannot change in such a local event, v must increase in order to maintain L. As luck would have it, that's exactly what happened.
And by luck, I mean the basic laws of physics.