Plausible cosmic event that could annihilate the earth

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Really - you should read up - its fascinating work

This matches with my request to provide references. So where are the sources for your claims?

Earthquakes are not events that make life on the surface impossible.

 

[Evo]

magnetic anomoly in pottery is how the field flip was discovered. Really - you should read up - its fascinating work. I wrote about it when the discovery was announced. I'm guessing the year but I think it would have been about 1990 or perhapsa little earlier - I'd need to check my records.

I'm afraid your posts about magnetic flips and pottery is misinformation.

You might be interested in reading the transcript of a NOVA episode about the Earth's magnetic field (I have posted about this for years here on PF).

The pottery is showing the strength of the Earth's magnetic field, it is not recording flips in the field.

Evidence of that decline has come from a surprising source. People have been making pottery for thousands of years. Archaeologists study pots to learn about ancient cultures. But these vessels have another story to tell.

JOHN SHAW: Pottery acts just like a magnetic tape recorder. It records the Earth's magnetic field when the pottery is first made.

NARRATOR: An ancient pot is a magnetic time capsule. John Shaw has learned how to extract from it a precise measurement of the strength of the magnetic field as it was in antiquity.

Like volcanic rock, clay contains tiny pieces of an iron-based mineral called magnetite. At the microscopic level, magnetite contains lots of distinct magnetic regions, in effect, tiny magnets. But in raw clay, these microscopic magnets all point in different directions, so they fail to create an overall magnetic field. That means a lump of clay on the potter's wheel is not, itself, magnetic. Not yet, anyway.

JOHN SHAW: Now the interesting part is when the pot's fired.

NARRATOR: The intense heat in the kiln erases all the magnetic regions. But as the pot begins to cool, new magnetic regions form in the magnetite. And as the regions reform, they align with the Earth's magnetic field, just like compass needles. With millions of tiny magnets all pointing in the same general direction, the pot itself becomes slightly magnetic. Once it has cooled, the magnetism is locked in.

JOHN SHAW: So if we take an ancient pot like this one, which is from Peru, when it cooled for the first time, it cooled in the Earth's ancient magnetic field and it became magnetized in that field. And of course, if the field's very strong, then the pot's strongly magnetized, and if the field's very weak, then the pot's weakly magnetized.

http://www.pbs.org/wgbh/nova/transcripts/3016_magnetic.html

Right now the Earth's magnetic field is about due to flip. Most scientists seem to be ignoring this.

More misinformation.

All these questions remain unanswered, though experts like Dennis Kent, the Rutgers University geologist who supplied NOVA with updated figures for the time line, are hard at work trying to answer them. In the meantime, not to worry. Reversals happen on average only about once every 250,000 years, and they take hundreds if not thousands of years to complete.

Even the weakening currently under way may be a false alarm. The field often gets very weak, then bounces back, never having flipped. As Ron Merrill, a magnetic-field specialist at the University of Washington remarked when asked whether we're in for a reversal: "Ask me in 10,000 years, I'll give you a better answer." So hang on to your compass. For the foreseeable future, it should work as advertised.

http://www.pbs.org/wgbh/nova/magnetic/timeline.html