OT: Earth\'s orbit changing?
 

According to this article: http://www.cnn.com/2004/TECH/science....ap/index.html

Since 1972, they have been adding a 'leap second' at the end of each year because the earth's movement through space is slowing down. But for some reason, in the most recent five years, the earth is no longer slowing down and they didn't have to add the leap second. They don't know why.

It seems to me that one second per year is a really big change, and it will really add up over millions of years? If the earth keeps slowing down like that, wouldn't the orbit decay and the earth spiral into the sun?

[Edit: mark topic as OT]

[ January 01, 2004, 17:49: Message edited by: Kamog ]

Re: OT: Earth\'s orbit changing?
 

It might vascillate, rather than steadily changing in one direction. The interior isn't solid, and we don't really know exactly what is going on down there. Lava-hampsters playing with their magnetic gyroscopes, maybe...

http://forum.shrapnelgames.com/images/icons/icon12.gif

PvK

Re: OT: Earth\'s orbit changing?
 

<font size="2" face="sans-serif, arial, verdana">there a little obsessive about those things, to.

Re: OT: Earth\'s orbit changing?
 

Hmm, there are only 31,536,000 seconds in a year. At a loss rate of one second per year we'd be falling into the sun in very short order on a geologic time scale. Obviously this cannot have been going on for long if the earth has been here for billions of years. There must be something funky going on that we don't understand. Maybe the sun's magnetic field is strong enough to slow us down at times? Or some sort of time-space warping is going on to make it look like the earth's orbital period is changing when it is not. It would be funny if they discovered there was some calibration error in their instruments....

Re: OT: Earth\'s orbit changing?
 

Hmmm...something on the order of a second per year might be caused by our solar system passing through a denser part of space....say like some thicker hydrogen clouds. Whether that extra amount of friction would make a difference of a second a year is anybody's guess.

They do say that there are signs that the poles of Earth's magnetic field are getting ready to flip again, and that just before that happens there will be a temporary decrease in the strength of our magnetic field. Again, it's hard to say what the result of that will be on the length of a year, but that will definitely be a bad century for laying in the sun. http://forum.shrapnelgames.com/images/icons/icon6.gif

Re: OT: Earth\'s orbit changing?
 

excuse my ignorance, but could we magnetically shield shelter's while that happens?

Re: OT: Earth\'s orbit changing?
 

Assuming we could shelter everyone, and design farming machinery to shield the operators so we could continue to grow food from our shelters, there is still a very large question of what happens to the eco-system during this time. Lots of additional radiation will be reaching the earth's surface and we can't protect all of it. Maybe the mystery of how evolution seems to run in 'fits and starts' will be answered when the magnetic field winks out for a few centuries during its flip... http://forum.shrapnelgames.com/images/icons/shock.gif

Re: OT: Earth\'s orbit changing?
 

Well, as the earths mass increases, the time to complete an orbit would increase. Laws of physics at work. And when the Last administration was in office, the mass of bull crap they were shoveling out had to have a noticeable impact on the planets mass. Ergo you have it, blame it on Clinton/Gore http://forum.shrapnelgames.com/image...s/rolleyes.gif

Re: OT: Earth\'s orbit changing?
 

<font size="2" face="sans-serif, arial, verdana">It will not be that bad. Even at the most extreme of the magnetic field flipping, the residual magnetic field will be strong enough to keep us safe. At worst, radiation will be like in polar regions today. All this stuff is good for scare stories in media but is in fact pretty harmless.

Re: OT: Earth\'s orbit changing?
 

I recall watching a show on the Discovery channel that talked about how the Moon is moving away from the Earth at an average rate of 2 inches per year and how that is effecting the Earths rotation. The mood acts as a stablizer and now that it has moved so far out away from the Earth, our oribit has begun to wobble more extremely than in years past.

Again this goes back to one of my old topics about how rare life realy is and that that rareness of life is extactly why I feel there are very few, less than 100 or so simular planets to earth in the galaxy that have humaniod type life of one type or another.

Re: OT: Earth\'s orbit changing?
 

<font size="2" face="sans-serif, arial, verdana">Oleg, I beg to differ. The Earth's magnetic field is the only thing that protects us from solar flares. Let us get hit by an X-class flare while the field is down, or even weakened, and it'll be a very different planet indeed.

Re: OT: Earth\'s orbit changing?
 

I am already depressed enough, I would rather not think about getting hit by an X-flare.

<font color=red>Avet your eyes if you are easily offended by comment about God.</font>

Why would God make such a beautiful planet and fill it with living things just to burn it to a cinder?

If the planet was to be burned to a crisp, of course that would fall under the insurance term, act of god.

People say trust in faith, well by my Last count God has racked up an impressive kill score. I think if God were human, he would be tried for genecide, or at the very least, as a mass murdering serial killer.

To think that God would let everything on this planet fry is a testimate to the fact that he is not a good god, not a nice god, but an evil insane creature that feeds off of pain and sufforing.

Of course that is just my depressed opinion at the moment and does not reflect upon how I might feel tomorrow.

Re: OT: Earth\'s orbit changing?
 

But Atrocities, maybe he considers us to be a failed creation and that would be his way of wiping the slate clean. Not that I would presume to know the mind of God.

Re: OT: Earth\'s orbit changing?
 

(not a very religious person either, so forgive me if anything)
To jump on the discussion - from that point of view, who said that human is the pinnacle of creation? And you cant trial god for murder, its the only way to get rid of people :roll:

Magnetic fields flip.... it was mentioned in my physics class, can someone elaborate on that for me? Oh, i can go and research it on my own, but from people's thoughts its usually clearer.

Re: OT: Earth\'s orbit changing?
 

Changing orbit? Failing magnetic shields? omg the "Polar Shift" theory is comming true. It's supposed to happen this year.

..due to the massive wieght accumilated over the centuries at the poles, the earth's crust will slide over it's molten core and the new (physical) north pole will end up in Saudi Arabia.

I remember, about two years ago, I heard about the polar shift theory and did a search on the net for info. I found a link to a site. As I read the article and got to the part where they said the new 'physical' north pole will end up in Suadi Arabia,.. there was a news bulliten on TV saying that it was snowing in Saudi Arabia. (They said that this was an extremely rare occurance) Coincedance? Or was a higher power giving me a clue?

..add to this that this year we have been having record snowfall and rain in december. Adding to the weight deposited in the northern hemisphere.

Interesting food for thought, very interesting.

Cheers! http://forum.shrapnelgames.com/images/icons/icon10.gif

Re: OT: Earth\'s orbit changing?
 

<font size="2" face="sans-serif, arial, verdana">Oleg, I beg to differ. The Earth's magnetic field is the only thing that protects us from solar flares. Let us get hit by an X-class flare while the field is down, or even weakened, and it'll be a very different planet indeed. </font><hr /></blockquote><font size="2" face="sans-serif, arial, verdana">But at no point of time it will disappear completely. Poles flip-flop is like a U-turn on a highway. You do not stop and reverse, you do some sort of imitation of Bond' movies chase. There won't a single moment when Earth has no magnetic field. Instead we will have many poles, some even on equator, some North poles in Southern hemisphere and vise versa. Nothern lights will be seen everywhere but that is it.

Disclaimer: The word "poles" used in this post refer to the physics term, not the citizens of Poland. http://forum.shrapnelgames.com/images/icons/icon7.gif

Re: OT: Earth\'s orbit changing?
 

What Oleg just said is about the way I understand it. Before a flip the Earth's magnetic field will become more 'patchy.' There will be multiple poles, and plenty of aurorae.

The Earth is a dynamo whose magnetic material is largely liquid. The changes are all supposed to be a result of change in internal flow. Once that evens out, so does the magnetic field. On a geological timescale, it will happen very quickly. As far as we're concerned, it will Last longer, but still not terribly long. http://forum.shrapnelgames.com/images/icons/icon6.gif

Stock up on sunscreen. http://forum.shrapnelgames.com/images/icons/icon12.gif

Re: OT: Earth\'s orbit changing?
 

I never understood this idea of the earth's magnetic poles moving around. How can the magnetic field, which was stable for a long period of time, suddenly reverse polarity? If the magnetic field is produced by the flow of molten material inside the earth, then it takes a tremendous amount of energy to change the direction of flow for so much mass. Where does this energy come from? Also, I thought that a flow of material will not produce a magnetic field unless there's an electrical current flowing through it. I mean, if you take a piece of iron and move it around where there's no magnetic field, it's not going to produce its own magnetic field, would it?

Re: OT: Earth\'s orbit changing?
 

<font size="2" face="sans-serif, arial, verdana">well, suppose the whole world reverted to human sacrifice? and then went worse. in that case, i think we should fry.
<font size="2" face="sans-serif, arial, verdana">every atom has it's own magnetic field. i don't know why you can only make a magnet out of ferrous material.

Re: OT: Earth\'s orbit changing?
 

<font size="2" face="sans-serif, arial, verdana">The mouse is right- pretty much everything produces a magnetic field. Its just that in most objects, the fields aren't aligned, so they pull in different directions and cancel each other out effectively. Iron and certain other materials are different in that you can force their fields to all point the way way.

The reason for the fields is electrons. They're moving about the nucleus, and they carry an electric charge. ANY moving charge produces a magnetic field. And vice versa.

Re: OT: Earth\'s orbit changing?
 

<font size="2" face="sans-serif, arial, verdana">yeah, but why?

Re: OT: Earth\'s orbit changing?
 

Because they are ferromagnetic elements. Such atoms are capable of remembering magnetic alignment, so materials made of them can be "magnets." Other elements and compounds are paramagnetic or diamagnetic. I forget which was which, but essentially, they are completely incapable of remembring a magnetic field. A field can be induced in them, but it is fairly weak (much weaker in one class than the other, though I forget which).

Re: OT: Earth\'s orbit changing?
 

<font size="2" face="sans-serif, arial, verdana">The magnetic field is not stable. It never has been, and never will be, unless the earth cools down and becomes a hunk of rock. The field is always in flux, due to the aforementioned movements of the liquid magma that is the bulk of the Earth's mass. The magnetic field of the Earth is always slowly changing. It reverses every few thousand years. This does not cause any significant increase in the amount of radiation that reaches the Earth's surface.

Re: OT: Earth\'s orbit changing?
 

<font size="2" face="sans-serif, arial, verdana">Everything that has a beginning has to have an end.

Re: OT: Earth\'s orbit changing?
 

<font size="2" face="sans-serif, arial, verdana">It will not be 'sudden' except from a geologic standpoint. It will take centuries. And yes, the earth is very large but that does not mean it has to be immutable. It does not rotate in a completely stable fashion either. It has a 'wobble' known as 'precession of the equinox' so who is to say that the currents of the interior cannot also 'wobble' somehow or other? The continents themselves are moving, bending, breaking, and getting shunted into the interior of the planet. Stability is an illusion.

What powers the earth's magnetic field is an interesting question. As far as I know, only an electric current can generate a magnetic field. So, somehow or other the earth's core is generating electricity. You'd have to ask some geologist who specializes in the dynamics of the 'deep' parts of the earth (dunno what the name for that specialty would be) for the prevailing theory on how that happens.

Geomagnetism FAQ from NOAA:
http://www.ngdc.noaa.gov/seg/potfld/faqgeom.shtml

Edit:

http://hyperphysics.phy-astr.gsu.edu.../magearth.html

Quote:

Magnetic Field of the Earth

The earth's magnetic field is similar to that of a bar magnet tilted 11 degrees from the spin axis of the earth. The problem with that picture is that the Curie temperature of iron is about 770 C . The earth's core is hotter than that and therefore not magnetic. So how did the earth get its magnetic field?

Magnetic fields surround electric currents, so we surmise that circulating electic currents in the Earth's molten metalic core are the origin of the magnetic field. A current loop gives a field similar to that of the earth.

The earth's magnetic field is attributed to a dynamo effect of circulating electric current, but it is not constant in direction. Rock specimens of different age in similar locations have different directions of permanent magnetization. Evidence for 171 magnetic field reversals during the past 71 million years has been reported.

Although the details of the dynamo effect are not known in detail, the rotation of the Earth plays a part in generating the currents which are presumed to be the source of the magnetic field. Mariner 2 found that Venus does not have such a magnetic field although its core iron content must be similar to that of the Earth. Venus's rotation period of 243 Earth days is just too slow to produce the dynamo effect.

Interaction of the terrestrial magnetic field with particles from the solar wind sets up the conditions for the aurora phenomena near the poles.

The Dynamo Effect

The simple question "how does the Earth get its magnetic field?" does not have a simple answer. It does seem clear that the generation of the magnetic field is linked to the rotation of the earth, since Venus with a similar iron-core composition but a 243 Earth-day rotation period does not have a measurable magnetic field. It certainly seems plausible that it depends upon the rotation of the fluid metallic iron which makes up a large portion of the interior, and the rotating conductor model leads to the term "dynamo effect" or "geodynamo", evoking the image of an electric generator.

Convection drives the outer-core fluid and it circulates relative to the earth. This means the electrically conducting material moves relative to the earth's magnetic field. If it can obtain a charge by some interaction like friction between layers, an effective current loop could be produced. The magnetic field of a current loop could sustain the magnetic dipole type magnetic field of the earth. Large-scale computer models are approaching a realistic simulation of such a geodynamo.

Endquote ---

The original has some diagrams and links to further information.

[ January 03, 2004, 22:20: Message edited by: Baron Munchausen ]

Re: OT: Earth\'s orbit changing?
 

In response to the earlier question about where does the power come from for the magnetic field:

The field itself is full of power.

Tether Experiment

Now if we can just tap it! Tesla was probably on the right track.

Re: OT: Earth\'s orbit changing?
 

<font size="2" face="sans-serif, arial, verdana">Everything that has a beginning has to have an end. </font><hr /></blockquote><font size="2" face="sans-serif, arial, verdana">But why? Does the universe have an end? Why can we not live forever without fear of being roasted alive by our own sun?

Re: OT: Earth\'s orbit changing?
 

<font size="2" face="sans-serif, arial, verdana">Is this something from the Matrix? http://forum.shrapnelgames.com/images/icons/icon12.gif

Well, I tried to think of something that has a beginning but no end, but I couldn't think of anything.

Re: OT: Earth\'s orbit changing?
 

<font size="2" face="sans-serif, arial, verdana">because if worse comes to worse, the Last detterent is fear. that is why the police have guns.

Re: OT: Earth\'s orbit changing?
 

because, atrocities, everything is cyclic.

Re: OT: Earth\'s orbit changing?
 

<font size="2" face="sans-serif, arial, verdana">Good judgment comes from experience and experience comes from bad judgment.

Re: OT: Earth\'s orbit changing?
 

<font size="2" face="sans-serif, arial, verdana">Is this something from the Matrix? http://forum.shrapnelgames.com/images/icons/icon12.gif

Well, I tried to think of something that has a beginning but no end, but I couldn't think of anything. </font><hr /></blockquote><font size="2" face="sans-serif, arial, verdana">Entropy. The universe began at (relatively) 0 entropy, but entropy always increases without end. http://forum.shrapnelgames.com/images/icons/icon12.gif

[ January 04, 2004, 03:39: Message edited by: Imperator Fyron ]

Re: OT: Earth\'s orbit changing?
 

<font size="2" face="sans-serif, arial, verdana">I thinkw e closed that one ages ago with the conclusions that
A) "Life" doesn't equal little greeen men but can be a 1 micro meter blob of green goo.
B) Life will be very common in the universe
C) How common intelligent life is is anybodys guess
D) How common humanoid type life is is anybodys guess

We just don't know how much advantage humanoid type life gives to a species... and we really need to if we are to make any resonable assumptions on its rarity/commonness

Re: OT: Earth\'s orbit changing?
 

<font size="2" face="sans-serif, arial, verdana">Well this isn't really true. From a pure physical point of view and if we don't iclude some of the weird new age quantum physics that allows from WEIRD STUFF TO HAPPEN for no apparent reason... the universe has a maximum level of entrophy.

It is when everywhere in the universe the temperature will be the same and when all mass will be equally distributed everywhere in the universe. That is when Entropy will be maximal.

But since the universe is expanding... who knows... the classical entropy definitions don't allow for an "inclosed system" to increae in volume as that would mean that some "External" force would have to act upon it...

Re: OT: Earth\'s orbit changing?
 

The very fact that the universe is expanding makes it true... if the universe expands, the particles keep moving outwards, thus increasing entropy.

Re: OT: Earth\'s orbit changing?
 

If I remember right, the theory in question says that the sun's electromagnetic field initiated Earth's magnetic field. Once the dynamo effect kicked in, the Earth's field became self-sustaining. Eddies in the flow of magma are what cause the local maxima and minima, similar to the way weather is created in the atmosphere.

Re: OT: Earth\'s orbit changing?
 

Circular truism plus circular truism equals unseen hampster powers.

PvK

Re: OT: Earth\'s orbit changing?
 

<font size="2" face="sans-serif, arial, verdana">Yes but you're forgetting the fact that the universe won't be expanding forever... it will prolly collapse back in again or slow expaing when the distances between particles become so great that the forces of gravity and whatever this force is that is pushing galaxies apart become equal.

Re: OT: Earth\'s orbit changing?
 

<font size="2" face="sans-serif, arial, verdana">and i'm still not allowed in there tunnels. you push one big red shiny, shiny button and they ban you for life!

Re: OT: Earth\'s orbit changing?
 

well, i bugged my physics teacher today, and the response i got was that: poles are always moving around, slowly, there is no such thing as a sudden move and they wont flip any soon.

anyone? http://forum.shrapnelgames.com/image...s/confused.gif

Re: OT: Earth\'s orbit changing?
 

Well, yes, the pole does shift around slowly all of the time. There was a news story Last year about the north magentic pole heading off into the Arctic Ocean (it has been in northern Canada in historic times) and they think it will go all the way to Russia.

http://www.cnn.com/2002/TECH/space/03/20/north.pole/

You can see a nice map of its drift during the time its location has been known at this page:

http://science.nasa.gov/headlines/y2...neticfield.htm

But the 'reversal' is something completely different than the usual drift. It's probably true that we won't see this flip occur in our lifetimes and that is all that 'really matters' for the pedestrian sort of person who doesn't read SciFi and speculate for themselves all the time like we 4X gamers do. http://forum.shrapnelgames.com/images/icons/icon7.gif

Re: OT: Earth\'s orbit changing?
 

<font size="2" face="sans-serif, arial, verdana">Maybe. You can not say for certain what is going to happen to the universe... There is nothing approaching consensus on what the fate of the universe will be. You can not say for certain that the universe will not be expanding forever. I suppose that if you want to get really picky I can add a qualifier of "while the universe is not shrinking" to my earlier statement. The problem is that evidence seems to indicate that the rate at which the galaxies are drifting apart is increasing, not decreasing.

Re: OT: Earth\'s orbit changing?
 

To return to the origional topic:

The earth's orbit slowing down is part of the earth-moon-sun orbital system and conservation of angular momentum (Jupiter also has an influence). The short of it is, because of this dynamic, the earth moves slightly away from the sun over time which causes its orbit to slow down. This is a good thing, due to the fact that the sun is slowly heating up over time.

The longer explanation is that the tidal forces between the earth and the moon slow down the earths rotation which reduces its angular momentum, but angular momentum must be conserved so the earth moves farther from the sun (creating a longer angular arm). Moving away from the sun means the earth's orbit must slow down to remain stable (but not as much as the angular arm increases angular momentum).

Makes sense?

Re: OT: Earth\'s orbit changing?
 

Good point, Lexicon. That is a steady influence that must be accounted for. But the original question involved what could cause a change of one second per year. It does not seem that tidal forces alone would cause a change of that magnitude. Yet, the discussion is beginning to accumulate a number of other, more transient things that may also be factors.

[ January 09, 2004, 15:18: Message edited by: Cipher7071 ]

Re: OT: Earth\'s orbit changing?
 

<font size="2" face="sans-serif, arial, verdana">But increasing the distance between the earth and the sun would would make earth orbit faster. Recall Kepler's third law, period^2 = distance^3.

Re: OT: Earth\'s orbit changing?
 

<font size="2" face="sans-serif, arial, verdana">You got the law right but the relationship wrong. Period is the inverse of speed. Therefore a longer period means a slower moving body. (Though it isn't really that simple due to the fact that an increased distence means a longer circumference of the orbit.)

[ January 09, 2004, 21:24: Message edited by: Lexicon ]

Re: OT: Earth\'s orbit changing?
 

In case you want the details:

period = t
circumference = L
speed = velocity = v

t^2 = d^3
L = 2(Pi)d
vt = L

Therefore vd^(3/2) = 2(Pi)d yielding v = 2(Pi)/d^(1/2) or speed equals twice pi divided by the square root of distance.

[ January 09, 2004, 21:58: Message edited by: Lexicon ]

Re: OT: Earth\'s orbit changing?
 

Dunno if this has any direct relevance to Earth's orbit or magnetic field, but the stuff swirling around under our feet appears to be getting more active. Yellowstone National Park is one big caldera, a 'supervolcano' and it is getting more active in the Last few years.

http://www.bbc.co.uk/science/horizon...olcanoes.shtml

And btw, after some Googling I think the issue is rotational speed, not orbital speed. I couldn't find anything about earth's orbit changing, and I don't think we can measure that accurately enough to notice 1 second's difference. But I did find articles about changes in Earth's rotation and how they have oddly noticed that some years they need a 'leap second' and other years they don't.

http://en2.wikipedia.org/wiki/Leap_second

http://www.astronomy.com/Content/Dyn...1/617efgfc.asp

http://www.astronomy.com/Content/Dyn...1/617efgfc.asp

Re: OT: Earth\'s orbit changing?
 

<font size="2" face="sans-serif, arial, verdana">The tidal forces between the earth and moon have no effect on our distance from the sun.

It does cause the moon to spiral outwards and the Earth's rotation (length of day/night) to slow, though.

The tides induced by the sun are a smaller effect, and those forces are exerted on a much heavier body...
If I recall the spin directions correctly, the solar tides would tend to push the earth in an outward spiral...

Re: OT: Earth\'s orbit changing?
 

<font size="2" face="sans-serif, arial, verdana">Since the year is almost 360 days, a difference of one day would translate to a shift of about 1 degree in the star field.
Similarily, a shift of one second, would cause the starfield background to shift by one 24th of a second of arc (1/3600th of a degree)
Google tells me that a 150mm telescope has a resolution limit of about 0.9 seconds of arc.
Larger research scopes would of course be better.

So, if the orbital period of Earth was off by a second, you should see a shift in the starfield relative to the sun, of about one arc-second.

[ January 09, 2004, 23:26: Message edited by: Suicide Junkie ]