Pangea Ultima: Earth in 250 Million Years? (APOD 22 Sep 07)

Qev · Post by **Qev** » Mon Sep 24, 2007 2:18 am

Seeing as an impact of that scale would melt the entire surface of the Earth, it's unlikely that the Pacific basin is a remnant of that collision.

rigelan · Post by **rigelan** » Mon Sep 24, 2007 4:40 am

Interesting tangents this conversation has turned into . . .

auroradude · Post by **auroradude** » Mon Sep 24, 2007 7:44 am

That's what I meant by "simplified". The impacting body didn't literally scoop out the Pacific but indeed melted the whole planet.
But it was this impact that left the planet "out of balance" and it has been trying to rebound from this event ever since.

jimmysnyder · Post by **jimmysnyder** » Mon Sep 24, 2007 11:25 am

I'm concerned that with all the continents shifted over to one side, that the earth will tip over. I have seen this happen before. Once I was waiting to make a left turn at an intersection that had no traffic light. I had to wait a long time because so many cars were travelling to my right even though the lane I wanted to turn into was empty. It seemed like so many cars were moving to the right that the earth would indeed tip over. About a week later there was a huge earthquake. Everyone was surprised except me.

geckzilla · Post by **geckzilla** » Mon Sep 24, 2007 1:32 pm

jimmy: Traffic patterns really have nothing to do with seismic activity. If that were true, we would have earthquakes every morning and evening as commuters traveled to and from work in various places where there are more people during the day than there are the night... think of a large city with surrounding suburbs and all the people come into the city to work during the day and they leave again during the night.

Really, NYC would have sunk into the ground by now. We are more like bacteria on a marble. Far away you can't see a single one of us and we live in a miniscule layer of earth.

jimmysnyder · Post by **jimmysnyder** » Mon Sep 24, 2007 7:34 pm

geckzilla wrote:Traffic patterns really have nothing to do with seismic activity.

I wouldn't be so sure. We don't have any written records of earthquakes going back more than 5000 years, about the time that chariots were invented.

rigelan · Post by **rigelan** » Mon Sep 24, 2007 10:34 pm

That's pretty good Jimmy.

geckzilla · Post by **geckzilla** » Tue Sep 25, 2007 2:49 am

Damn, you tricked me! I was thinking this site was becoming a sad magnet for wackos. I was the turkey all along.

goredsox · Post by **goredsox** » Tue Sep 25, 2007 3:02 am

The impacting body didn't literally scoop out the Pacific but indeed melted the whole planet. But it was this impact that left the planet "out of balance" and it has been trying to rebound from this event ever since.

So with this theory it would seem that all earthquakes today are actually aftershocks from the original mega-impact that blasted the moon out of our primordial planet, in the sense that the tectonic plates were partially propelled by such an imbalance.

It is curious that the earth is mostly a giant, spherical blob of liquid or semiplastic molten minerals (with the exception of a relatively small inner core, and the thin crust that we inhabit). A large impact would blast a large chunck of already molten material out into earth orbit.

But since the earth is ostensibly cooling slowly, wouldn't the crust eventually get so thick that the moving continents would get "stuck" and stop drifting? Probably would take a lot more than the 250 million years in the original APOD image.

auroradude · Post by **auroradude** » Tue Sep 25, 2007 9:51 am

It sure would be interesting to compare seismic records and tectonics from another planet about the size of Earth without a moon...
...say Venus for example.

jimmysnyder · Post by **jimmysnyder** » Tue Sep 25, 2007 12:05 pm

No one is buying my image of the earth tipping over like an egg the day after an equinox? How about a moment of silence for the passing of Marcel Marceau?

Andy Wade · Post by **Andy Wade** » Tue Sep 25, 2007 4:45 pm

jimmysnyder wrote:No one is buying my image of the earth tipping over like an egg the day after an equinox? How about a moment of silence for the passing of Marcel Marceau?

Shouldn't that be a moment of noise?

goredsox · Post by **goredsox** » Tue Sep 25, 2007 11:35 pm

It sure would be interesting to compare seismic records and tectonics from another planet about the size of Earth without a moon...
...say Venus for example

Yeah, I agree.......

Am I correct in stating the our Moon is the only Moon in the Solar System that is thought to have formed from a collision, rather than from a capture of an asteroid or a comet?

Also it would seem that tectonic movements on Earth are unique for other reasons too, such as the unique balance of mantle temperature and crust temperature, planet density, the gravitational mass, and so on. One is hard pressed to come up with another body in the solar system with anything like our tectonics. Maybe Io, and the shared factor may be the intense tidal forces of a rapid orbiting relationship (in our case, the moon; in Io's case, Jupiter).

inertnet · Post by **inertnet** » Tue Sep 25, 2007 11:47 pm

Suppose the Earth was smaller and more dense before, like suggested on the website that was linked in this thread. If its mass didn't change significantly over time, but only its density became lower and its size became bigger at the same time, wouldn't gravity be reduced in the process? That would imply that this theory can possibly be checked. Is there any way to determine Earth's gravity in the past?

rigelan · Post by **rigelan** » Wed Sep 26, 2007 2:28 am

Intertnet. If the earth has become less dense, then yes it would affect the gravity at the surface of the earth. It would be slightly less. But it would not affect how the earth's gravity pulls on the moon or any such other force, only the force on the surface of the earth.

But I would be at a loss to know what particular item to look for in the history of the earth. Water levels? Rock densities?

Galactic Groove · Post by **Galactic Groove** » Wed Sep 26, 2007 2:11 pm

rigelan wrote:Intertnet. If the earth has become less dense, then yes it would affect the gravity at the surface of the earth. It would be slightly less. But it would not affect how the earth's gravity pulls on the moon or any such other force, only the force on the surface of the earth.

Are you sure about that??? Last time i checked, gravity doesn't pick an area to affect more than another area. If gravity is recorded as being weaker in one area, it'll be weaker everwhere else too, regardless of distance.

Galactic Groove · Post by **Galactic Groove** » Wed Sep 26, 2007 2:26 pm

auroradude wrote:It sure would be interesting to compare seismic records and tectonics from another planet about the size of Earth without a moon...
...say Venus for example.

Is there any "tectonic" activity on Venus? Venus is constantly turning itself inside out so I dont' believe that would allow for much in the way of plate development like we have here on Earth.

geckzilla · Post by **geckzilla** » Wed Sep 26, 2007 7:18 pm

You guys better tell Google to take into account the expanding of the earth's circumference before they lay their fiber optic cable across the pacific...

rigelan · Post by **rigelan** » Wed Sep 26, 2007 10:48 pm

Assuming a perfectly spherical earth, The gravitational acceleration at the surface of the earth would be a=G M / R^2

G is a constant. And in this particular situation, we are keeping the (M)ass of the earth constant, and yet expanding the (R)adius of the earth. So M is a constant, but R is increasing.

Since R is on the bottom side of the equation, as R increases, (a)celleration would decrease.

So if the earth expanded without changing its mass, the acceleration due to gravity on the surface of the earth would be less.

jimsaruff · Post by **jimsaruff** » Thu Sep 27, 2007 12:47 am

Did anyone ever explain the 'lost 50 micrograms' of the International Kilogram Cylinder in Paris?

BMAONE23 · Post by **BMAONE23** » Thu Sep 27, 2007 5:02 am

hungry mouse???

BMAONE23 · Post by **BMAONE23** » Thu Sep 27, 2007 5:04 am

what does the cylinder contain?

If something wet, possible evaporation. If something dry, maybe desication of a minute ammount of water

jimsaruff · Post by **jimsaruff** » Thu Sep 27, 2007 5:38 am

It's the International Standard Kilogram cylinder. I believe it is platinum and some one or two other metals. It was formed in the 1800's, I believe.

Did you not see in the news a week or so ago that it had mysteriously lost 50 micrograms, as I recall. They made nine of these standard kilogram cylinders and kept one under lock and key (I imagine the others were also) under very controlled conditions. The rest were distributed internationally to set the agreed upon weight for the kilogram.

Anyhow, apparently they weighed the standard of the standards recently and it was 50 micrograms lighter. I was wondering if, as unimaginable as it seems, just how much of an increase in the radius of the earth would produce just such a loss.

Sorry if I went on too long here.

auroradude · Post by **auroradude** » Thu Sep 27, 2007 8:53 am

Has evaporation ever occured to anyone?

If I am thinking correctly, even though most atoms or molocules of a mass might not be at the point of turning liquid or gaseous from a solid at the time, some of them, maybe only a few of them, are. They just bounce around all day and slap each other around and some of them get hit "just right" and it sends them into orbit, or right out of it.
They leave the mass.

geckzilla · Post by **geckzilla** » Thu Sep 27, 2007 1:10 pm

I wouldn't be surprised if some Frenchie just got finger oils on it and over the course of 200 years it flowed off the thing.

Starship Asterisk*

Pangea Ultima: Earth in 250 Million Years? (APOD 22 Sep 07)

less gravity