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I am sure there is a lot of great science, data, and tons of work by a lot of people behind this video. But I am having a hard time shaking the thought "How cou

I am sure there is a lot of great science, data, and tons of work by a lot of people behind this video. But I am having a hard time shaking the thought "How could they possibly know that". Just mind blowing that it could recreate all that movement. Imperfect as to the details, sure. Thank you for sharing.

tim333 8y ago
I was wondering how they figured it too. There must be some guess work. It seems to work a bit like doing a jigsaw puzzle where if say the shapes and fossil species match you can figure they were next to each other at the time of the fossils. https://www.geolsoc.org.uk/Plate-Tectonics/Chap1-Pioneers-of-Plate-Tectonics/Alfred-Wegener/Fossil-Evidence-from-the-Southern-Hemisphere https://www.geolsoc.org.uk/Plate-Tectonics/Chap1-Pioneers-of...
- sizzzzlerz 8y ago
  This is what science does. It's human attempts to explain the natural world we observe and to make suggestions as to how it got that way and how it works. Scientists don't claim that they have the final answer or that ancient events had to have happened they way they explain. They are just claiming an explanation that is consistent with the facts and observations they have.
- gameswithgo 8y ago
  shapes, rock formations, mineral content, magnetic striping. There are lots of clues.
peterlk 8y ago
A geologist I know very well has remarked to me before that before a certain point, the geological records aren't good enough to know. The problem is that continents get pushed under each other, and their contents are recycled through the earth in complex (fluid dynamics) ways. So, we can be pretty confident up to a certain point (for some reason, 2 billion years feels right in my brain, but I might be making that up - I think it's correlated with the oldest rocks in Australia?), but after that point, the records are so muddled that it's pretty hard to come up with a confident picture. So saying "this is what the earth looked like 4 billion years ago" is an imprecise endeavor
- njarboe 8y ago
  The continents rarely get pushed under each other, but the ocean floor does commonly get pushed under the continents and back down into the Earth. The Himalayas are the exception where two continents have hit and are still moving toward each other with a lot of crust getting smashed and pushed up much higher than usual. But even in this case the continental crust is not going back into the earth. It is much less dense than the rock below it and thus will "float" on top. Reconstruction of where the plates were in the past is mostly determined by paleomagnetism (subject area of my PhD). When lava erupts and cools, it gets magnetized in the direction of the earth's magnetic field. This can be measured directly in the rocks themselves or seen as magnetic anomalies in the oceans. Since the magnetic field flips directions every 1/2 million years or so (a somewhat random process) the rocks around the ocean ridges that are spreading and erupting continuously all get magnetized in one direction and then another. This produces magnetic anomaly stripes that have been measured all over the world. Using these ocean stripes, which can be treated like slices in time, it is quite straight forward to reconstruct what Pangea, the most recent supercontinent, looked like and where it was located when it began to break up about 175 million years ago. Almost all of the current ocean floor was created after this breakup, so before that reconstructions become much more difficult. This a very simplified explanation. The older the rock, the less likely the original magnetization was preserved. Also, the continents have been growing slowly over the 4.5 billion history of the earth. The earth was almost all ocean at the start. The oldest rocks known are about 3.2 billion years old, so before that almost nothing is known about the magnetic field of earth (some older zircons survive in these rocks, but they are unlikely to preserve a record of the magnetic field). The wikipedia entry on plate tectonics is a decent place to start to read more about the process.
  - peterlk 8y ago
    If the Earth's magnetic field flips somewhat randomly every 1/2 million years, and there is randomness in that timing, how can it be a reliable measurement mechanism at 50 million years? 500 million years? 2 billion years?
    - njarboe 8y ago

tim333 8y ago

I was wondering how they figured it too. There must be some guess work. It seems to work a bit like doing a jigsaw puzzle where if say the shapes and fossil species match you can figure they were next to each other at the time of the fossils. https://www.geolsoc.org.uk/Plate-Tectonics/Chap1-Pioneers-of-Plate-Tectonics/Alfred-Wegener/Fossil-Evidence-from-the-Southern-Hemisphere https://www.geolsoc.org.uk/Plate-Tectonics/Chap1-Pioneers-of...

sizzzzlerz 8y ago
This is what science does. It's human attempts to explain the natural world we observe and to make suggestions as to how it got that way and how it works. Scientists don't claim that they have the final answer or that ancient events had to have happened they way they explain. They are just claiming an explanation that is consistent with the facts and observations they have.
gameswithgo 8y ago
shapes, rock formations, mineral content, magnetic striping. There are lots of clues.

peterlk 8y ago

A geologist I know very well has remarked to me before that before a certain point, the geological records aren't good enough to know. The problem is that continents get pushed under each other, and their contents are recycled through the earth in complex (fluid dynamics) ways. So, we can be pretty confident up to a certain point (for some reason, 2 billion years feels right in my brain, but I might be making that up - I think it's correlated with the oldest rocks in Australia?), but after that point, the records are so muddled that it's pretty hard to come up with a confident picture. So saying "this is what the earth looked like 4 billion years ago" is an imprecise endeavor

njarboe 8y ago
The continents rarely get pushed under each other, but the ocean floor does commonly get pushed under the continents and back down into the Earth. The Himalayas are the exception where two continents have hit and are still moving toward each other with a lot of crust getting smashed and pushed up much higher than usual. But even in this case the continental crust is not going back into the earth. It is much less dense than the rock below it and thus will "float" on top. Reconstruction of where the plates were in the past is mostly determined by paleomagnetism (subject area of my PhD). When lava erupts and cools, it gets magnetized in the direction of the earth's magnetic field. This can be measured directly in the rocks themselves or seen as magnetic anomalies in the oceans. Since the magnetic field flips directions every 1/2 million years or so (a somewhat random process) the rocks around the ocean ridges that are spreading and erupting continuously all get magnetized in one direction and then another. This produces magnetic anomaly stripes that have been measured all over the world. Using these ocean stripes, which can be treated like slices in time, it is quite straight forward to reconstruct what Pangea, the most recent supercontinent, looked like and where it was located when it began to break up about 175 million years ago. Almost all of the current ocean floor was created after this breakup, so before that reconstructions become much more difficult. This a very simplified explanation. The older the rock, the less likely the original magnetization was preserved. Also, the continents have been growing slowly over the 4.5 billion history of the earth. The earth was almost all ocean at the start. The oldest rocks known are about 3.2 billion years old, so before that almost nothing is known about the magnetic field of earth (some older zircons survive in these rocks, but they are unlikely to preserve a record of the magnetic field). The wikipedia entry on plate tectonics is a decent place to start to read more about the process.
- peterlk 8y ago
  If the Earth's magnetic field flips somewhat randomly every 1/2 million years, and there is randomness in that timing, how can it be a reliable measurement mechanism at 50 million years? 500 million years? 2 billion years?
  - njarboe 8y ago