By MICHAEL JOHN UGLO
This is the seventh geoscience conference in the earth science series.
The earth interacts with so many physical entities.
These come from inside the earth like volcanism, plate tectonics, geodynamo, convective mantle, seafloor spreading, as well as its surrounding environment like atmosphere, magnetosphere, ionosphere and the cryosphere.
The structure and composition of the earth is affected by entities such as magma from below. The primordial thermal energy composing the booster with almost 80% of the heat of the earth’s core going through radioactivity. The generation of heat by radioactivity is caused mainly by the radioisotopes Potassium-40, Uranium-235. Uranium-238 and Thorium-232.
This enormous heat is the origin of the convective mantle which causes plate tectonics as well as the geodynamo which becomes the source of the earth’s magnetic force and electromagnetism. The flow of heat from the interior of the earth to its boundaries such as the mantle core and the lithosphere also transmits this heat by conduction.
The heat creates a magnetic nature of the earth which protects the earth from the dangerous solar wind which is decimating the earth. It helps by diverting harmful rays which are highly radioactive and highly ionizing so that life on earth is safe.
Earth’s gravity exerts its force on the moon while the moon exerts its gravity on the earth. This has the effect of the high tides and the two low tides observed on the sea during a lunar day of 24 hours and 50 minutes. They are separated by 12 hours and 25 minutes at each alternation.
Earth’s gravity exerts a strong pressure on the upper layers of the overlying rocks. It is compressed and therefore increases its density as the depth increases. Measurements of the magnitude of the earth’s gravitational acceleration as well as the gravitational potential will help determine the nature of plate tectonics. They can also be used to locate mineral deposits.
Magnetism, electromagnetic waves, heat fluxes, vibrations, electricity, radioactivity, fluid dynamics and mineral physics are all areas of investigation that form interacting physical systems. Geomagnetic dipoles are very close to the geographical poles of the planet. The magnetic nature of the formed earth produces the magnetic reversals as can be seen in the geo-stratigraphic rock samples. Magnetic reversals can be observed on rocky beds in the sea as a result of seabed spreading are evidence comparing geo-stratigraphic samples obtained from geo-stratigraphy.
Electromagnetic waves are observed in the magnetosphere, the mantle as well as the core of the earth. The magnetohydrodynamics of the nature of the core as well as the convective mantle cause the electromagnetic waves of the earth. This causes the magneto-telluric which physicists can use to do geophysical mapping.
Knowing gravity and more specifically the gravitational acceleration as well as the gravitational potential of the Earth’s surface will help identify the movement of plates known as plate tectonics.
The earth’s heat flow from the interior to the surface is by convection as well as conduction through its two boundaries which are the core/mantle and the lithosphere. This heat transfer is the cause that generates the earth’s magnetic field after forming the base of the geo-dynamo that generates this magnetic field. This heat flux at the earth’s surface is about 4.2 x 1010 kilowatts. This is the basis of geothermal energy that we see on the surface of the earth.
There are natural vibrations on the earth. These vibrations are natural throughout the earth due to the oscillating atoms and molecules due to the heat of the core and the convection mantle. The vibrations are measured using a seismograph. The study of these natural wave patterns of the earth is called seismology.
Wave generation from a particular wave such as earthquake can be measured from different sources to identify the epicenter or source of the wave. Waves can be reflected and measured to determine differences in structures and compositions. The waves can be diffracted and allow the geophysicist to determine the different densities of the structure and composition of the earth. The structure and probability of the earthquake can be identified to recommend the engineering structures that can withstand shocks and earthquakes.
There is electricity flowing through the earth in the global circuit. The atmosphere is bombarded by the high energy short wave frequency of cosmic rays. Thus, it leaves the atmosphere positively charged. Therefore, a voltage of 120 is observed after every meter on the earth. This equates to approximately 1800 amps of current flowing through the overall circuit. Current flows towards ground while electrons flow upwards.
This trend reverses directions during thunderstorms when the current flows upward and results in sprites in the air and lightning on the earth’s surface. The electromagnetic induction of the earth caused by the weather variation and the geomagnetic nature caused by the convective mantle against the rotation of the earth as well as the moving bodies of the conductive marine waters against the permanent magnetic poles of the earth cause the presence of flow of telluric electric current on the earth.
The presence of underlying earth structures with their varying electrical resistivities will help geophysicists identify the composition of different earth structures. For example, groundwater flow can be identified as groundwater can allow electricity to flow.
Electromagnetic waves are generated by the ionosphere, the magnetosphere as well as the liquid part of the outer core of the earth. The electromagnetic induction caused as a result of the movement of the metallic outer core in the molten liquid state against the two natural poles of the earth causes the electric, electric and magnetic currents. These telluric electric and magnetic fields can be used for geo-survey.
The earth’s magnetic fields are used to deflect the harmful solar wind that sweeps through the solar system and is highly radioactive and therefore ionizing. It can destroy plant and animal life on planet Earth.
The earth’s magnetic field of both poles is also used for navigation as well as with the use of compasses. The poles of the earth are tilted and lie very close to the geographic poles. Magnetic poles shift and full magnetic reversals are considered evidence on bedrock.
Magnetostratigraphy on geologic stratification has complete magnetic reversals on the seabed that indicate many geologic years. Stripes on the seabed provide rich and detailed information on seabed propagation. Magnetic reversals can be used with magnetostratigraphy to determine time scale and magnetization can be used to determine earth motion.
Radioactivity on earth causes the most heat. The decay of unstable radioactive elements become the sources that allow their measurements using Geiger-Muller counters to determine the dates of materials such as rocks on the surface of the earth as well as around it such as the atmosphere. This is called radiometric dating. Mapping of atmospheric radioisotopes by gamma spectrometry of the ambient air and on the surface of the ground makes it possible to map the concentration and distribution of this radioisotope over time in this zone.
In fluid dynamics, the magnetosphere, the ocean, the mantle, although fragile but considered over a long period, and the outer core all determine the corolla effect of the earth. It also affects the study of physical oceanography, the circulation of winds, storms and weather patterns as well as the circulation of seas and oceans as well as meteorology. The magnetohydrodynamics of the magnetosphere can be modeled from the waves and phenomena of the magnetosphere.
In mineral physics, the composition and content of minerals are very important in determining the structure and composition of the earth. Temperature and pressure at different levels shape the mineral contents which can be demonstrated with the temperature and pressure phase diagrams. It also helps in the study of seismology with these diagrams to extract quantitative data about the structure and composition of the earth.
High temperature and pressure contribute to the movement of the movement of tectonic plates. The thermal gradient is also considered to be the result of this enormous temperature of the earth’s core.
It has enormous effects on water masses in the hydrosphere. Water with its unique physical and chemical properties undergoes processes such as coalescence, supercooling and supersaturation to result in the different precipitation modes such as rain, snow, ice and groundwater flow.
Groundwater after infiltration and percolation has the properties to respond to electric and magnetic surveys in geophysical surveys. The salinity of the seas and oceans has a huge effect on their movements.
In addition, the cryosphere also occurs in the form of sea ice, freshwater ice, glaciers, frozen ground surfaces such as permafrost, and ice caps.
My prayer for PNG today is: “Where were you there when they crucified my Lord…”
Next week: The geophysical regions of the earth
- Michael Uglo is a science textbook author and professor of avionics, autopilots, and aeronautical engineering. Please send your comments to: [email protected]