Without the magnetic field generated by the earths liquid iron core two thousand miles beneath our feet we wouldn’t have the spectacle of the Northern Lights.
This is a phenomena whereby the magnetic field producing the North and South Poles at either end of the earth have the strongest magnetic pull. Charged particles emitted from the sun during increased sunspot activity, also known as coronal mass ejections, create radiation also known as ‘solar wind’ which dragged toward the North and South poles.
The magnetosphere is a magnetic shield that protects us from the majority of this solar radiation but the charged particles which do get though do so during increased activity during the suns 11 year cycle.
The bright colours are generated when the charged electrons and protons collide with the gases in the earths atmosphere and are converted into photon energy that lucky observers can see when near the poles at night during increased sun spot activity. Oxygen in the upper atmosphere emits green or orange-red, depending on the amount of energy absorbed. Nitrogen emits blue or red; blue if the atom regains an electron after it has been ionized, red if returning to ground state from an excited state.
Scientists have discovered how the Earth’s magnetic field fluctuates, but also weakens and reverses dramatically every 200,000 years or more. The next flip is overdue and scientists have observed significant weakening of the magnetic field over the last 100 years decreasing in strength about 5 percent per decade and some believe this is the beginning of a polarity reversal. During this event the earth’s magnetic shield is reduced and the charged particles would hit the earth everywhere on the side facing the sun, creating an Aurora spectacle for everyone to see. The downside is that there would be a corresponding increase in cancer rates as we are bombarded with harmful radiation we are currently protected from by our magnetic field.
This image shows a computer generated model of the Earth’s fluctuating magnetic field thousands of years ago based on data from lava samples which have fixed the earths magnetic field in the rock as they cooled down.
In the piecing together of the moving magnetic field over 100’s, 1000′ s and millions of years brings together unlikely disciplines analysing navigational maritime charts, ancient pottery and geo magnetic core samples.
This film helps visualise the aurora and how the earth’s polarity is due to flip : http://www.aurora-service.eu/aurora-school/aurora-borealis/
The Planck space observatory used by the ESA 2009 – 2013 gathered magnetic field data of our Milky Way galaxy producing this image.