For example, ferrous metals such as iron become magnetic when enough particles have their spin in the same direction, creating a magnetic field with the same polarity as the spin. The right hand rule states that our fingers indicate the direction of the magnetic field (B) when we point our thumb in the direction of the current (I).
At the heart of circular motion is the interaction between moving charged particles and magnetic fields. This is the excited state in carbon-12 (12C) at 7.654 MeV, which plays a key role in the formation of carbon in stars and – consequently – the existence of carbon in the universe.
Large Hadron Collider SA-CERN programme
THEME | PALAEOMAGNETISM
The polarity of the Earth's magnetic field can flip and has changed many times in the past. Remanence and the Curie Temperature Rocks can become magnetized and capture the Earth's magnetic field. Using rocks of different ages, we can trace the movement of the Kalahari craton back 3.5 billion years.
Michiel de Kock is head of the Department of Geology at the University of Johannesburg. The tilt at a particular time, here 1,850 million years ago, reveals the location of the North Pole in relation to the craton.
Observing the Earth’s magnetic field
In 1932, to celebrate the International Polar Year, a magnetic observatory was established at the University of Cape Town. But the subsequent electrification of the commuter rail network caused a disruptive impact, to the point that accurate observations became almost impossible. In the years since the Hermanus Magnetic Observatory was established in 1941, the facility has been operated by various institutions, and in 2011 it became part of SANSA's Space Science Programme.
The splitting of the South Atlantic Anomaly in two is clearly seen in this image of the field strength of Earth's magnetic field, as measured by ESA's SWARM satellite constellation. The official opening ceremony for a new, state-of-the-art facility took place on March 9, 2021.
CURRICULUM CORNER
Expansion could perhaps be achieved through international cooperation, as was the case with the establishment of the Keetmanshoop observatory with the support of the German GFZ research center for geosciences. SANSA is currently in the process of upgrading its Hermanus facility into a 24-hour operational space weather centre. Under an agreement with the International Civil Aviation Organization, this will serve as a regional center for the provision of space weather services for the African region.
South Africa is also uniquely positioned to study the South Atlantic Anomaly (SAA), where the geomagnetic field is weaker by about 40% compared to other locations at similar latitudes due to processes in the Earth's core. Although it was originally discovered by satellite missions in the late 1950s, data from the European Space Agency's Swarm satellite constellation, launched in November 2013, has revealed that the SAA has split in two since 2014.
SPACE RESEARCH
Some regional space weather projects, such as those focused on potential hazards to the local power grid industry, as well as mineral exploration companies operating in southern Africa, could benefit from the addition. SANSA could also expand the time domain of data collection by moving to continuous monitoring with sampling rates of 10 Hz or higher, which could be used for research and high temporal resolution applications. It is also moving westward at a rate of 20 km per year, expanding the anomaly's area of influence, as evidenced by an observed weakened magnetic field over southern Africa.
A weaker field means that the shielding effect is significantly reduced in this area, allowing high-energy particles to penetrate deeper into the upper atmosphere than here.
Birds, brains and magnetic fields
At the beginning of autumn in the northern hemisphere, they leave in large flocks for the northeastern Indian subcontinent, where they gather in enormous numbers. While magnetic materials such as magnetite respond to the poles of a magnetic field, researchers in the field of quantum biology have proposed an alternative bird compass that responds to the tilt of the geomagnetic field. The inclination compass, which depends on how the magnetic field lines are tilted relative to the Earth, is called the radical pair mechanism and is based on the science of spin chemistry.
This is the basis of the radical pair mechanism of bird magnetoreception, which depends on the paired spins of the two electrons and how they react to the Earth's magnetic field. Whether the paired spins are in a singlet or triplet state determines what chemical product is made, which then feeds directional information to the bird's brain.
Seeing below the ground
These induced electric currents are called eddy currents, and their behavior depends on the conductivity of the medium in which they flow. The eddy currents create their own magnetic fields, which can be measured and analyzed to obtain information about underground conductivity. Similar to magnetic surveys, EM surveys can be conducted on the ground or from airborne platforms.
Depending on the nature of the electric current in the source loop, EM methods are divided into two broad categories: frequency domain and time domain methods. The decay rates depend on the conductivity of the subsurface materials: faster decay rates occur at lower conductivities.
Groundwater exploration
This residual field contains information about the positions, depths, geometries and orientations of the magnetic bodies responsible for the observed anomalies. Contour map of the residual magnetic field (in nanoTesla, nT) recorded across a section of a large dyke that partially underlies the city of Bloemfontein. An important property of EM waves is that the depth of the wave's penetration into a conducting medium is inversely related to the wave's frequency: waves with higher frequencies have smaller penetration depths.
However, the inconvenience of being temporarily without electricity was a small price to pay because the results of the survey allowed a major fault zone to be located at a depth of over 200m. The output shown above is a contour map of the apparent conductivity at a depth of 0 .5 m below the surface.
MAGLEV
This was not the first maglev system to be implemented - the technology was invented in the 1960s, and a number of smaller and much slower versions have either been retired or are still in operation. Musk 'open sourced' the hyperloop concept and encouraged others to contribute to the design process to help bring the idea to life. Its proprietary maglev technology is based on the Inducttrack system developed at the US Lawrence Livermore National Laboratory in the 1990s and optimized for a low-pressure environment by the HyperloopTT.
Both also made presentations to the US Congressional Subcommittee on Railroads in May 2021, as part of a hearing on “The Benefits and Challenges of High-Speed Rail and Emerging Rail Technologies.” In October of that year, the Maryland state government confirmed that it had issued a conditional permit to Musk's The Boring Company to begin digging a 10-mile (16.5 km) tunnel on its property under the Baltimore-Washington Parkway, the 35-mile (56 km) highway between the two cities.
THE INNOVATION TRAIN
He is commemorated in a towering bronze statue unveiled by the Lord Mayor of the City of London in 1994. The resurrection plant Myrothamnus flabellifolia – believed to be one of the oldest plants on the planet – is widely used in African traditional medicine. She is also working to ensure that the farmers who grow the plant are remunerated according to its value and that royalties are paid to the elders of the communities who first discovered its medicinal properties.
Here we examine the report through a South African lens and – as two South African lead authors of the report – identify five messages that are critical to the Southern African region and its people. Note in this context that the 'long-term global goal' of the Paris Agreement on Climate Change is to limit global warming to values well below 2°C above pre-industrial levels, preferably below 1.5 °C.
Climate Change
First, that every ton of CO2 we emit contributes to global warming: this leads to the consequence that if we stop emitting, the temperature will stop rising, which is the basis of the net-zero concept . Globally, South Africa is one of the top five countries in terms of CO2 emissions per energy unit. It is both an enormous challenge and an unprecedented opportunity for the modernization of the country.
To ensure that global warming remains below the 1.5°C level until the end of the century and beyond, the IPCC assessment shows that an additional global intervention beyond net zero emissions is needed: the active reduction in atmospheric CO2 through negative emissions. The IPCC Working Group 1 report, entitled Climate Change 2021: the Physical Science Basis, is the first installment of the IPCC's Sixth Assessment Report (AR6), which will be completed in 2022.
Animal home-building habits may provide clues to climate change adaptation
Like beaver dams, bird nests, burrow systems, and termite mounds are extended phenotypes because they are modifications that animals consciously make in their local environment. The researchers are calling for a renewed effort to understand what role extended phenotypes play in the animals' experience of climate variability. This information can improve the predictive power of climate change models that aim to predict the effects of climate change, including how species' ranges may change, what the relative risks of extinction are for different animal groups, and which species will thrive, all of which have important consequences for human food safety and disease risk.
Written by Quest Editor, Sue Matthews, using press releases from three of the universities and other sources. The school will conduct research, coordinate curriculum development and facilitate postgraduate training, advice and consultancy, as well as technology transfer in the many areas of climate studies.
Starting out on a STEM career
STEMulator is an interactive research platform designed to stimulate students' curiosity in the world of science, technology, engineering and mathematics. The initial image, which serves as the main menu, has clickable areas that provide more information about object-specific layers. The STEMulator Car unpacks into different parts, allowing users to explore how the engine or control system works.
The STEMulator is still in the beta testing phase, and the development team is looking for contributions to expand the content of some areas. The STEMulator is an initiative of proSET, the membership sector of the National Science and Technology Forum (NSTF).
STEMulator
In addition to learning about the technology, users can find out about relevant career opportunities, such as electrical or mechanical engineering, and which institutions offer these fields of study. The Academy of Science of South Africa (ASSAf) recently launched a booklet it commissioned to educate students, teachers and the general public about the Covid-19 crisis.
Essential facts about Covid-19
Books
The Living Deserts of Southern Africa
Test your knowledge
Not only is Rhodes University ranked in the top 10 universities in South Africa, but also in the QS Global World Rankings 2021 at #801-1000.
Academy of Science of South Africa (ASSAf)
