What would happen if the earth's core were to solidify?

Earth's liquid core is what is believed to create the earth's magnetic field. No magnetic field means no poles. Without that magnetic field, which acts as a shield, the solar wind would blow away most of the earth's atmosphere and things that like oxygen would be kaput. Bad news for humans. Scientists can see what happens when they check other planets that are smaller, like mars, whose core has cooled to a solid and caused the magnetic field (shield) to disappear.

Information on our core (both inner and outer)

The outer core of the Earth is a liquid layer composed of iron and nickel above the solid inner core. It comprises approximately 22.37% of Earth’s mass. Its outer boundary lies approximately 2,890 km (1,800 mi) beneath the Earth's surface, below the mantle. The temperature of the outer core ranges from 4400 °C in the outer regions to 6100 °C near the inner core. Eddy currents in the nickel iron fluid of the outer core are believed to influence the magnetic field of the Earth. It is above the inner core. The outer core is not under enough pressure to be solid, so it includes the same contents as the inner core, but it's liquid. (Wikipedia)

the inner core is a solid the outer core is a liqude because when we get earthquakes there are 2 diffrent typs of wavelengths, there are s waves and there are p waves , s waves can not travel through the liquid part of the core (mantal) but the p waves can pass the the mantle but when they reach the core they get distorted or deflected that is why they think the core is solid. to answer your question on the polarity problem a study of rock magnatisim conducted during the 1950s in europe led to an interested descovery. the magnetic alignment in the iron rich minerals in lava flows of diffrent ages indicated that many different paleomagnetic poles once existed. a plot of the apparent positions of magnetic north pole with respect to europe revealed that during the past 500 million years, the location had gradually wanderd and is still moving to day due to plate movment

Actually, pretty good question. Since it is speculated that the magnetic field is induced mt the liquid iron core, we would most indeed loose that. All of the weather patterns would change for one. Also, if you were to violate the pressure, volume, and temperature laws of the core, I think that we would be in for one big shock as it cooled and contracted. I am sure that there are many more answers, but definitely say goodbye to those polarities!

There are a number of theories that indicate the center of the earth is solid (a ball of nickel I believe). So, presuming they are true, it would be just like it is now. ;)

But, I know you are looking more for the magnetic field changes ... it would affect a lot of subtle things on a global scale and anyone of these things could cause all life to cease to exist (if there is ever a "break" in the food chain, like all bees dying and no more pollination, then most indications are that life on the planet has 8 or so years to live).

I wonder if ther is a correlation between the dinosaur extinction and a pole reversal of some sort.

Anyway ... lot of interesting info here.

http://news.bbc.co.uk/2/hi/science/nature/3359555....

Without the swirling of the molten iron in the core, there would be no more magnetic field to protect the earth from cosmic radiation.

The Earth's inner core IS solid!

people the earths inner core is solid, its so compact that the particles cant move to be a liquid