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Physics, Astronomy & Cosmology / Where can I go to begin to understand the math of M-Theory?

« on: 03/08/2019 16:20:39 »

I understand that M-theory emerged as a merger between 5 different string theories and supergravity.

How did these theories get started in the first place? Am I right in thinking that there is no experimental evidence of any of it? And that it just emerged because the math worked out so well?

All I know is that they say "vibrating strings" and 9 spacial dimensions plus time (for string theory), and 11 dimensions for supergravity. But other than repeating that same stuff, where can I go to start trying to understand it on a deeper level?

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Geology, Palaeontology & Archaeology / Relatively how large was the mantle plume linked to the Permian mass extinction?

« on: 22/06/2019 07:10:49 »

The Permian Mass Extinction (~250 Mya) is said to have happened primarily due to volcanic activity from a mantle plume "super volcano" that created the Siberian Traps. This eruption is said to have lasted for millions of years.

How does the size of this mantle plume compare with the mantle plumes of today? What is the largest mantle plume today? I've heard different things from different sources. Is it the on under Iceland (and is this the same one that erupted 250 Mya), or is it Hawaii? Yellowstone? Tasmania?

I don't think that Yellowstone is the largest one... so why does that one get to most attention?

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Geology, Palaeontology & Archaeology / How can the crust be thicker in eastern Canada than it is in the Rockies?

« on: 30/07/2008 21:52:22 »

Hey Guys.

Here's something I was wondering.

How can the crust be thicker in eastern Canada (the craton) than it is in the Rocky Mountains even though the elevation is so much higher in the Rockies?

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Geology, Palaeontology & Archaeology / Does Water Penetrate All Of The Continental Rocks At Sea Level And Below?

« on: 16/07/2008 10:41:52 »

Does Earth's water penetrate the continental rock at sea level all over the world?

It seems like it would.

Does that mean that the water is always saline if you drill to below sea level?