Alternate Unvierse Geography

[matsuiny2004]

I am writing a book, but I am a little stuck and had a scientific/philosophy question to ask. If Earth had different Geography as in none of the known continents existed as they do now could they still be Earth?

[Turtle]

I am writing a book, but I am a little stuck and had a scientific/philosophy question to ask. If Earth had different Geography as in none of the known continents existed as they do now could they still be Earth?

 

earth is earth. 3rd rock from the sun and all. :smilingsun: the geography is ever in flux and geologists have characterized a number of past "super-continents" as well as projected some future ones.

 

List of Supercontinents

[Eclogite]

Something you may wish to consider when writing your book is an oft repeated remark by a friend of mine who was a geography major. He was useless at knowing where anywhere was, but woul defend that ignorance thus: Geography isn't about where places are, but about why they are there.

[Guest MacPhee]

Something you may wish to consider when writing your book is an oft repeated remark by a friend of mine who was a geography major. He was useless at knowing where anywhere was, but woul defend that ignorance thus: Geography isn't about where places are, but about why they are there.

 

Your friend's remark is intriguing, but very alarming. Suppose your friend was a history major. And he was useless at knowing when any event had happened. That's to say, he had no idea of the date of the event.

 

So for example, he didn't know that the US Declaration of Independence was in 1776, and the US Civil War started in 1861. He thought the dates might be the other way round.

 

Would you regard him as a credible historian?

 

I'd think he was a charlaton. Like a so-called geographer, who didn't know where places are. That's just commonsense, isn't it?

[CraigD]

I am writing a book, but I am a little stuck and had a scientific/philosophy question to ask. If Earth had different Geography as in none of the known continents existed as they do now could they still be Earth?

Well, as Turtle noted, “third rock from the Sun” Earth is Earth no matter what it’s continents look like, and they’ve looked very different in its past than they do now, and will look very different in its future. But maybe this question is equivalent to a phrasing of the classic alternate history question: “could some small difference in an alternate version of the Earth’s past history result in its geography in that history’s year 2011 being much different than they actually are in now?”

 

I imagine 2 main aspects of this question, corresponding to viewing Earth on a self contained scale vs. a solar system-wide one.

 

One, is physical geography chaotic? that is, critically dependent on initial conditions? Does the famous Lorenz “butterfly” effect apply, where, say, the flapping of the wings of a flying insect 304 billion years or so (this would have been nearly the first winged insect) results in, there being a supercontinent now, rather than the present broken up and spread out arrangement?

 

Two, were important events in Earth’s past driven by chaotic factors? Especially, could the giant impact of the Mars-size body “Thea” believed to have occurred about 4 billion years ago, which resulted in the formation of Moon, have been significantly different due to nearly random factors? Earth’s basic geographic starting point, then, would be very different.

 

I’m pretty confident the answer to question two is yes. Orbital dynamics are known to be chaotic on large and small scales, so factors such as the angle and speed of the Earth-Thea impact could have been very different, the result being a significantly lower or higher mass of the Earth and Moon, and a very different world than the one we now live on.

 

I lean toward, with about 50% confidence, answering question one in the affirmative. In either case, I think it’s reasonable science fiction to imagine an Earth with a physical geography consisting of nearly any physically possible arrangement of continents, weather (which, though not strictly geography, effect geography), etc.

 

Something you may wish to consider when writing your book is an oft repeated remark by a friend of mine who was a geography major. He was useless at knowing where anywhere was, but woul defend that ignorance thus: Geography isn't about where places are, but about why they are there.

Every Physical Geography or Geology major or professor with whom I’ve had conversation at length eventually said essentially what your friend did: it’s less important to know precisely how the Earth’s stuff is arranged as it is than to understand the dynamics that cause it to be as it is. Geographers and geologists are “big picture” scientists, vs., say, paleontologists, who are more concerned with geological details that impact their subject matter.

 

The reader may have noticed I quality my references to geography with “physical” throughout this post. This is important, as there are the academic disciplines of physical and human (AKA cultural) geography are very distinct, having little technical matter in common.

 

I'd think he was a charlaton. Like a so-called geographer, who didn't know where places are. That's just commonsense, isn't it?

Though as I note above, in my experience, when explaining their discipline to non-colleagues, physical geographers are inclined to stress the unimportance of “where places are and what they’re named” details, once they’ve been in the discipline long enough to have succeeded, they tend to as a matter of necessity be pretty damn expert in these details, both in general an in their area of specialization. So I agree, a geographer who really doesn’t have a good grasp of the names and locations of geographical features and their related political ones is likely either not a very good one, or just pretending not to in order to make a point.

[Shirley_Rocks]

 

Every Physical Geography or Geology major or professor with whom I’ve had conversation at length eventually said essentially what your friend did: it’s less important to know precisely how the Earth’s stuff is arranged as it is than to understand the dynamics that cause it to be as it is. Geographers and geologists are “big picture” scientists, vs., say, paleontologists, who are more concerned with geological details that impact their subject matter.

 

 

I have to take exception to the remark about paleontologists, having worked closely with several over the years. All of the paleontologists I've known are interested in more than just their favorite time period or fossil, but how that fossil, and moreover, it's ecological niche, can tell stories about the big picture of what was happening on Earth at the time of its existence. It's paleontologists who have probably collected more data that has helped reconstruct Pangaea and all of the stages in between. Part of what Alfred Wegener noted when he first developed his then-rejected hypothesis about "continental drift" was the appearance of similar fossils and rock strata in seemingly unrelated places. Many paleontologists are interested in constructing extinction events (smaller than the known big 5), which tell us about global climate, across continents, which is hardly "small picture" thinking.

 

Anyway, if the OP is still reading, a good animation of the continents is here: http://www.ucmp.berkeley.edu/geology/anim1.html but BRACE YOURSELF for the web design and the cry of 1995 calling to return its website back into its arms. It's all based on work done by Chris Scotese, who has an extensive list of visualizations and other resources here: http://www.scotese.com/ He's also a paleontologist ;)

 

I don't know whether it matters to the story, but weather is influenced by the position of the continents. The Scotese links above have some information in that regard, but some of it might be a bit much for a lay person.

[sigurdV]

I am writing a book, but I am a little stuck and had a scientific/philosophy question to ask. If Earth had different Geography as in none of the known continents existed as they do now could they still be Earth?

 

You might be interested in an old philosophical controversy about "Contrafactual Situations".

The latest contributor I know of is Saul Aaron Kripke...

 

The question of when, or if, two objects with non identical environment can be identical is too deep for me to attend properly in here right now.

 

(But my tentative wiew on the matter is that any object x is not fully determined unless we know of both x and all that is not x. I think the only way out here is to ask: Exactly what is meant by "Earth"?)