The earth is growing?

[Supermans]

Originally Posted by irpq11

Ok, so if I followed the equation right then .............................. I would be smart.

But, good question. Why isn't the moon expanding?

Anyone?

As smart as the people who create the technobabble on Star Trek.. Or as smart as Obama's teleprompter .

[Mr_Draco]

Originally Posted by irpq11

Ok, so if I followed the equation right then .............................. I would be smart.

But, good question. Why isn't the moon expanding?

Anyone?

Since the moon doesn't have a molten and active core that isn't really a good question. A better question is why is Earth the only planet expanding even though there are other planets and moons in our solar system with an active core as well but yet they're not expanding?

[PQ]

Originally Posted by Supermans

As smart as the people who create the technobabble on Star Trek.. Or as smart as Obama's teleprompter .

Originally Posted by Mr_Draco

Since the moon doesn't have a molten and active core that isn't really a good question. A better question is why is Earth the only planet expanding even though there are other planets and moons in our solar system with an active core as well but yet they're not expanding?

[DGthe3]

the claim was made that the earth has doubled in size? Did it double in radius? Area? Volume? Land area makes the most sense considering the topic that was discussed. Doubling in area means that the volume would be 2.83x larger. So density would then have to have gone down by an equal factor for mass to remain the same. So, given that the current density for the earth is ~5.5g/cc, it would have had to have a density of 15.6 g/cc before expansion. This is halfway between the density of lead and gold.

One other problem with this though, if the earth had to double in area while maintaining the same mass, the force of gravity at the surface would have been twice as strong before it grew. Unfortunately, this would have made dinosaurs impossible to stand.

If the earth had significantly less mass eons ago, the moon would never have maintained a stable orbit. Since we have a moon and dinosaurs fossils, I think that proves that this guy is talking out of his ass.

[CamaroSpike23]

[kdbolt70]

Originally Posted by DGthe3

the claim was made that the earth has doubled in size? Did it double in radius? Area? Volume? Land area makes the most sense considering the topic that was discussed. Doubling in area means that the volume would be 2.83x larger. So density would then have to have gone down by an equal factor for mass to remain the same. So, given that the current density for the earth is ~5.5g/cc, it would have had to have a density of 15.6 g/cc before expansion. This is halfway between the density of lead and gold.

One other problem with this though, if the earth had to double in area while maintaining the same mass, the force of gravity at the surface would have been twice as strong before it grew. Unfortunately, this would have made dinosaurs impossible to stand.

If the earth had significantly less mass eons ago, the moon would never have maintained a stable orbit. Since we have a moon and dinosaurs fossils, I think that proves that this guy is talking out of his ass.

I agree, and the gravity at the surface is something I didn't really piece together at the time. Using the equation I mentioned, gravity would be a bitch at the surface. This would infer smaller animals than we see today, rather than larger ones. (Though, I guess you could argue the atmospheric pressure would also be increased, meaning more molecules of oxygen per unit volume. More oxygen = larger animals).

I really think the only credible argument is that the Earth did not gain much mass, but rather lowered its density. I was working on some equations with densities of magma vs temp and pressure, but I don't feel like going through it all right now. Basically, you'd have to have a pretty amazing material to double its volume in a cooling process. I don't think anything like that exists.

[Vash]

No I think it did gain lot of mass from impacts and that's why dino cousins are smaller. Little big more gravity.

[PQ]

Originally Posted by CamaroSpike23

It never showed Tattoine or Romulus.

[PQ]

Originally Posted by kdbolt70

Well, he's right and wrong, in a sense. I'll try to explain There is a very important mathematical equation that defines gravity:

F = GMm/R²

F is the Gravitational force
G is the Gravitational constant, 6.67*10^(-11) N-m²/kg².
M is the mass of object 1 (we'll say the earth)
m is the mass of object 2 (the moon)
R is the radius between the two object's center of gravity

The last part is important. Notice the equation says nothing about volume, or density. All that matters is mass (no pun intended :p). So, regardless of the earth's size, assuming it had the same mass, the moon would revolve around it at relatively the same distance. Whether the earth was the size of a basketball, or the size it is now. (granted if it was the former, it would probably end up as a black hole!)

Now, whats really interesting about the moon in this theory is its creation. Its believed that the moon was created from a very early collision between the earth and a meteor. A chunk of molten earth was blasted off in to space, and slowly coagulated into our modern day moon.

To do this, the meteor was pretty big in relation to the Earth, something like 1/4 the size of present day Earth. If earth had been much smaller, the metor would have had a much larger effect on our planet.

Also, why isn't the moon expanding?

Originally Posted by DGthe3

the claim was made that the earth has doubled in size? Did it double in radius? Area? Volume? Land area makes the most sense considering the topic that was discussed. Doubling in area means that the volume would be 2.83x larger. So density would then have to have gone down by an equal factor for mass to remain the same. So, given that the current density for the earth is ~5.5g/cc, it would have had to have a density of 15.6 g/cc before expansion. This is halfway between the density of lead and gold.

One other problem with this though, if the earth had to double in area while maintaining the same mass, the force of gravity at the surface would have been twice as strong before it grew. Unfortunately, this would have made dinosaurs impossible to stand.

If the earth had significantly less mass eons ago, the moon would never have maintained a stable orbit. Since we have a moon and dinosaurs fossils, I think that proves that this guy is talking out of his ass.

Ok, so did we establish that it would be unlikely that the moon could have remained in it's current orbit throughout the proposed theory or not?

[kdbolt70]

Originally Posted by Vash

No I think it did gain lot of mass from impacts and that's why dino cousins are smaller. Little big more gravity.

Someone earlier in this thread ran a quick equation, showing it was basically impossible to accrue this much matter in the period of time given.

Aside from the matter accrual theory, the matter "creation" theory, and the density reduction theory, there is another theory that could conceivably be viable. It basically suggests the gravitational constant itself is decreasing, meaning gravity is getting less powerful. This would mean the gravity exerted by the earth would put less force on the matter being drawn to the center, and therefore it would expand. This is pretty farfetched, as we haven't observed this value changing, but heck, it could be possible. I do think, however, that a decreasing G would have much larger impacts on the universe than just earth swelling a bit.

Originally Posted by irpq11

Ok, so did we establish that it would be unlikely that the moon could have remained in it's current orbit throughout the proposed theory or not?

No, we established the opposite. If the matter remained constant in the Earth, the moons orbit would be pretty much the same as it is now.

However, if we accrued mass, the orbit would definitely be different, or possibly even unsupportable.

[CamaroSpike23]

Originally Posted by kdbolt70

Someone earlier in this thread ran a quick equation, showing it was basically impossible to accrue this much matter in the period of time given.

Aside from the matter accrual theory, the matter "creation" theory, and the density reduction theory, there is another theory that could conceivably be viable. It basically suggests the gravitational constant itself is decreasing, meaning gravity is getting less powerful. This would mean the gravity exerted by the earth would put less force on the matter being drawn to the center, and therefore it would expand. This is pretty farfetched, as we haven't observed this value changing, but heck, it could be possible. I do think, however, that a decreasing G would have much larger impacts on the universe than just earth swelling a bit.



No, we established the opposite. If the matter remained constant in the Earth, the moons orbit would be pretty much the same as it is now.

However, if we accrued mass, the orbit would definitely be different, or possibly even unsupportable.

what about the specific gravity of earth billions/millions of years ago. a denser core along with a greater gravitational field that has slowly weakened over the millenia allowing for the outer crust to expand? which would also correlate to the moon gradually moving away from us as well?

[PQ]

:upset: So where did the moon come from? If the earth doubled in size, then the moon at some point was only half the size of the earth, so surely the moon wasn't split of of the earth?

[kdbolt70]

Originally Posted by irpq11

:upset: So where did the moon come from? If the earth doubled in size, then the moon at some point was only half the size of the earth, so surely the moon wasn't split of of the earth?

Well I thought about this as an argument to debunk the growing earth theory, but the more I thought about it, the more I felt it was possible to fit it into this theory. The most prominent moon creation theory is the concept of a mars-sized meteor colliding with the primordial earth to expel a large amount of matter into space, which then formed the moon over time.

Initially, you'd think "if the earth was so much smaller back then, wouldn't a mars-sized collision cause more damage?" but really, if the earth had roughly the same mass it does today, the collision would have the same momentum effects (Newton's second law of motion). Also, if the matter was much more dense back then, the earth would need to expel a smaller volume of it to form the moon. So realistically, even though the earth was half its current size, it still could have given off the same amount of mass to form the moon, though not the same volume of matter. The molten material would have cooled much quicker in a smaller package, and so it expanded faster to reach the size the moon is today. Since volume and density have nothing to do with gravity, this concept could work.

[PQ]

So in your opinion this theory is plausible?



I would think that the mountain ranges wouldn't fit the theory. the earth sould be much smoother.