My Science School

Freeman Dyson may be gone, but his famous alien-hunting idea will likely persist far into the future.

Dyson, a quantum physicist who died at age 96 on Feb. 28, recalled in a 2003 interview just how he first advanced his concept of a "Dyson sphere," which could betray the existence of an advanced alien civilization. 

A Dyson sphere is a theoretical mega-engineering project that encircles a star with platforms orbiting in tight formation. It is the ultimate solution for living space and energy production, providing its creators ample surface area for habitation and the ability to capture every bit of solar radiation emanating from their central star

Because of their infrared radiation, Dyson spheres are considered a type of technosignature — a sign of activity that distant astronomers could use to infer the existence of intelligent beings in the universe, according to a NASA report. A handful of Earth-based researchers have scanned infrared maps of the night sky in hopes of spotting Dyson spheres, but so far, nobody has seen anything out of the ordinary.

In 2015, astronomer Tabetha Boyajian, then at Yale University, reported on the mysterious dimming of light from a star called KIC 8462852, whose irregular flickering looked like nothing researchers had ever seen before. Other scholars suggested the weird light dips could result from a partially built Dyson sphere, and the idea caused a media sensation. Campaigns to look for other signs of technological activity from the entity, which came to be known as Tabby's star in honor of Boyajian, have turned up empty, and most researchers now think the object's light patterns have some kind of nonalien explanation.

 

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The genius in the wheelchair

When Stephen Hawking was 21, he was given only a few years to live after being diagnosed with a rare form of motor neurone disease. Undaunted, Hawking made breakthroughs in quantum physics and cosmology with his "The Theory of Everything" and his work on black holes. Although a number of biographies have been written about the genius, a new memoir gives an affectionate account of Hawking and his indomitable spirit.

Written by Leonard Mlodinow, who worked closely with Hawking for nearly 11 years and co-authored two bestselling books with him ("A Briefer History of Time" and "The Grand Design"), "Stephen Hawking - A Memoir of Physics and Friendship gives fresh insights into Hawking's character and his famous sense of adventure and fun.

A daredevil

Hawking was born on January 8, 1942 in Oxford. At 17, he won a scholarship to study at University College, Oxford. Despite his brilliance in academics, Hawking hated studying. According to his own estimates, he studied for only 1,000 hours during his three undergraduate years at Oxford. Once he even joined the college boat dub. But earned himself a daredevil reputation as he steered his crew on risky courses that often damaged boats.

Living with a rare disease

After being diagnosed with a rare form of motor neurone disease known as ALS, Hawking sunk into depression. Though the disease progressed slowly, it began to interfere with his daily activities, and his condition worsened in 1985 during a trip to Cern. Hawking underwent a tracheotomy, which saved his life but destroyed his voice. He started using a voice synthesiser.

The early diagnosis of the terminal disease ignited a sense of purpose in Hawking and he embarked on his career in earnest. He pursued his work with black holes and relativity with new zest. In 1988, Hawking published "A Brief History of Time, which turned him into an instant icon.

Writing for children

Hawking and his daughter Lucy came up with a series of illustrated books to explain the "secret keys to the universe" to young readers. The books deal with complex topics, including the Big Bang, black holes, atoms. planets and their moons, in the form of space adventures embarked on by junior astronaut George and his best friend Annie. The series helped simplify cosmology for children.

Love for adventures

Hawking enjoyed his fame, taking many opportunities to travel and to have unusual experiences such as going down a mine shaft visiting the south pole and undergoing the zero-gravity of free fall, and to meet other distinguished people.

Legacy

Hawking died at his home in Cambridge on March 14, 2018, at the age of 76. In the same year in June, Hawking's words, set to music by Greek composer Vangelis, were beamed into space from a European Space Agency satellite dish in Spain with the aim of reaching the nearest black hole 1A 0620-00.

 

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The Moon has fascinated us for centuries with several countries already having sent their probes and people to explore it But how was Earth's closest companion formed? Well there have been many theories about the formation of the Moon. The one that many scientists agree with the most is the giant-impact hypothesis.

When Earth was hit by Theia

Scientists believe the Moon was formed when a planet about the size of Mars collided with Earth Theia, as dubbed by scientists crashed into Earth when it was still a very young planet This collision sent dunks of Earth's cast into space Gravity then bound these particles together in space forming the Moon.

The Apollo missions conducted by NASA between 1969 and 1972. brought back over a thing of a tonne of rock and soil from the Moon. When this was analysed it was found that the Earth and the Moon hat some chemical and isotopic similarities, suggesting that they have a linked history.

However, this theory has its challenges with many models suggesting 60% of the Moon would have been made up of Theia's rocks if the giant-impact hypothesis is true.

The other theories

Prior to the Apollo missions, there were three theories that were speculated about the formation of the Moon.

Capture theory: This suggests the Moon was a wandering body in space, like an asteroid which formed elsewhere in the solar system and was captured by Earth's gravity when it passed near the planet.

Accretion theory: This theory suggests the Moon was created along with Earth during its formation 

Fission theory: According to this theory, the Earth was spinning so fast that some of its material broke away and began to orbit it after being captured by its gravity.

 

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We all know the basics of volcanoes. They are spots on the Earth's crust from where molten rock, volcanic Ash and certain gases can escape from an underground chamber. The molten rock is called magma when it is below the ground and lava when it erupts and may start flowing across the Earth's surface. Volcanoes are broadly classified as active, dormant and extinct, based on their activity.

This much is well known and part of our textbooks. But a group of scientists revealed in 2020 certain explosive secrets that volcanoes had so far hidden deep underneath. They were able to show that volcanoes whose eruptions have been consistent actually hide chemically diverse magma underground with the potential to thereby generate explosive activity.

They did this by studying two Galapagos volcanoes that have erupted compositionally anion lava flows throughout their lifetimes. But after studying the compositions of microscopic crystals in the lavas, the reconstructed characteristics of magmas was contrary to expectations.

As opposed to the monotonous lavas that erupted at the surface level. magmas were extremely diverse. including compositions similar to the most violent of volcanic eruptions in history. This implies that volcanoes that for millennia have erupted a certain way actually have the ability to undergo inspected changes.

Knowing this is important because hazard evaluation and evacuation models currently employed have worked under certain assumptions. By realising that just because a volcano has erupted a particular way in the past doesn't necessarily mean it will continue that way indefinitely in the future, we can better assess the risks posed by them.

 

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Research Scientists. Chemists, physicists, and all scientists who work to make new discoveries are called research scientists. They go to school for a long time to learn their subject. When they are finished with school, many research scientists work for businesses. Some work for the government of their country. Some work in universities. Do you like to find out how things work? Would you like to make guesses to explain something and then do experiments, or tests, to find out if you are right? Do you like to tell other people about your ideas and discoveries? If so, you may want to become a research scientist yourself!

The purpose of scientific research is to gather information and generate knowledge using both theoretical and experimental means. This work is often divided into pure research, where as yet there is no intended application, and applied research, which has a set target.

Research scientists contribute to knowledge in the fields of the natural sciences, medical science, computer science, environmental science and the social sciences. They make hypotheses, collect data and interpret results in order to answer questions about humans and the natural world. Research scientists normally have either a masters or doctorate degree in their specific fields of study, such as Physics, Biology, Biotechnology, Chemistry, Computer Science, Environmental Science or Psychology.

A position as a research scientist in industry is different from one at a higher education institute or at a research institution.

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Physicists. Physics is another physical science. Scientists who study physics are called physicists. Physicists study matter, or the “stuff” all things in the universe are made of, and energy. They also study forms of energy, such as heat, light, sound, and electricity. Atomic physicists study atoms and the parts of atoms. The things learned by atomic physicists led to the invention of new kinds of weapons as well as new ways of creating energy.

Physicists typically specialize in one of many subfields, and some will go further to specialize in a subdivision of one of these subfields. However, all physics involve the same fundamental principles.

Atomic, Molecular and Optical Physics - is research on atoms, simple molecules, electrons and light, and their interactions

Astrophysics - is the study of physical processes in stars and other galactic sources, galactic structure and evolution, the early history and evolution of the universe, and the sun and solar activity

Biological Physics - is the study of biological phenomena using physical techniques

Chemical Physics - provides understanding for a broad range of systems, from atomic collisions to complex materials, as well as the behaviour of the individual atoms and particles that make up the system

Computational Physics - explores the use of computers in physics research and education, as well as the role of physics in the development of computer technology

Condensed Matter Physics - concentrates on such topics as superconductivity, semi-conductors, magnetism, complex fluids, and thin films

Fluid Dynamics - is the study of the physics of fluids with special emphasis on the dynamical theories of the liquid, plastic and gaseous states of matter under all conditions of temperature and pressure

Laser Science - or laser physics is a branch of optics that describes the theory and practice of lasers

Materials Physics - applies physics to complex and multiphase media including materials of technological interest, and uses physics to describe materials in many different ways such as force, heat, light and mechanics

Nuclear Physics - is the study of fundamental problems related to the nature of matter

Particles and Fields - is the study of particles and fields, their interrelationships, interactions and structure, and the design and development of accelerators and instrumentation techniques for high energy physics

Physics of Beams - is the study of the nature and behaviour of beams and the instruments for their production and use

Plasma Physics - plasma, solid, gas and liquid are the four states of matter. Plasma physics is the study of plasma charged particles and fluids interacting with electric and magnetic fields.

Polymer Physics - focuses on the physics of natural and synthetic macromolecular substances.

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The scientists throughout the world are hard at work. Some are studying atoms and molecules. Others are making discoveries about chemicals, liquids, heat, light, motion, or sound.

Physical scientists learn about how things work in the world and in outer space. They study all matter that is not alive, from tiny atoms to stars and planets.

Scientists work in every field imaginable, and can therefore be found working for an expansive range of employers. Large and small companies will hire scientists to work on products and research projects. Universities will hire scientists to do research work or to teach. Governments and hospitals issue research grants and hire scientists to work on funded projects. Regardless of the path the scientist decides to follow, the ultimate goal is to always add knowledge and insight to the larger scientific community, as well as to help ignite new discoveries for the future.

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Chemists. One of the physical sciences is chemistry. Chemists study chemicals and other materials to find out what they are made of. They also learn how these things change when they join with other substances. Chemists take molecules apart and put them together in new ways. They try to find out how chemicals can be used to make things people need, such as fuels, medicines, plastics, and thousands of other materials. Some chemists study how light, heat, and other forms of energy change chemical substances.

A chemist will often work as part of a larger research team in order to create much needed compounds for use in a wide variety of practical applications. A chemist also works to improve the quality of established chemical products and utilizes advanced computer programs to establish new technologies in the field.

Almost every industry benefits from the theories and chemical compounds brought about by research in the chemical sciences.

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Electricity in a wire creates the pushes and pulls that get work done. It lights lamps and runs machines. But electricity has another important use. It can carry information. Thanks to electricity’s ability to carry information, we have tiny radios, handheld calculators and video games, and personal computers.

The use of electricity to carry electric signals is called electronics. These electric signals may stand for sounds, pictures, numbers, letters, computer instructions, or other sorts of information.

An electronic device has many tiny electrical pathways called circuits. Each circuit has a special job. Some circuits store signals. Others change signals. For example, in an electronic calculator, one circuit might add two numbers together. When the answer is reached, another circuit sends a signal that light up a display screen to show the answer.

The circuits in most of today’s electronic devices are mounted on a chip, a piece of material that is no bigger than a fingernail.

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Electricity can make light and heat. It can also make a magnet. But this is a magnet you can turn on and off.

A magnet made with electricity is called an electromagnet. An electromagnet has two parts. The first part is a solid centre, or core, made of iron. The second part is an outer covering made of wire that is coiled many times around and around the solid iron core.

When an electric current runs through the wound wire, the iron becomes a magnet. The iron gets its pull, or magnetism, from the moving electrons in the wire. As soon as the electric current is turned off, an electromagnet loses its magnetism.

Electromagnets are used to make electric motors run. A motor has two sets of these magnets - an outer set that stays in place and an inner set that moves. The inner set of electromagnets is attached to an axle - a rod that can spin. When the motor is turned on, the two sets of electromagnets push and pull against each other. That push makes the inner magnets move and spin the axle. And the spinning axle gives a push that makes the motor run.

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A torch runs on electricity, but you don’t have to plug it in. It carries its own electric current in a “package” - a battery.

A battery is made of layers of chemicals inside a metal container. When the torch is turned on, some of the chemicals in the battery break apart and eat away at the metal container. As this happens, some of the metal atoms leave the container and combine with the chemicals inside the battery.

As the metal atoms move away from the container, they leave some of their electrons behind. So the container gains electrons. And as the chemicals inside the battery break apart, they lose electrons.

Soon, there are more electrons in the container than there are inside the battery. Then the extra electrons in the container begin to move out of the battery. They travel through the bulb and back into the middle of the battery, where electrons are scarce. The push of these electrons is the current that makes your torch shine.

It may sound as if everything happens very slowly, but, as you know, it all takes place in an instant.

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You want your electric clock to run day and night. But you wouldn’t want your doorbell ringing all the time. Things like doorbells, lamps, and radios work only when you turn them on.

Most things that run by electricity have a switch. A switch is used to turn the electric current on and off. The electric current moves along the wire and across the switch to another wire inside the bell, lamp, or radio. The switch is a “bridge” in the path the electricity follows.

A metal piece inside the switch moves when you turn the switch on and off. When you turn the switch on, the metal piece touches both wires. The “bridge” is down. The electricity coming into the switch can cross the “bridge” and keep travelling along the pathway.

When you turn the switch off, the metal piece moves away from the wire. The “bridge” is up. Without the “bridge,” the electric current can’t cross the switch and follow the path. So, the electric current stops moving, and things stop working until you lower the “bridge” in the pathway by turning the switch on again.

An electric current is a push in a wire - the push of moving electrons. But what makes the electrons start to push through the wire? Where does the current come from?

The electric current is made in a kind of “electricity factory” called a power plant or power station. The special machine that makes electricity is called a generator.

A generator uses a huge, spinning magnet to make electrons move. The pull of the spinning magnet is strong enough to start electrons pushing in a wire.

The magnet is surrounded by a large coil of tightly wound wire. When the magnet begins to spin, its pull starts millions of electrons pushing! This push makes a strong electric current in the coiled wire. The current is sent through other wires from the power plant to your home.

A generator makes electrical energy. But a generator uses energy, too. Running water, burning fuel, or nuclear energy runs the engines or other machines that make the huge magnets spin. So a generator actually is an energy-changing machine. It changes other kinds of energy into electrical energy - energy you can use.

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When you use electricity to iron your clothes or toast your bread, two things happen. Electricity makes a strong push in a wire, and the wire pushes back!

Electricity makes the iron and the toaster heat up. The electricity travels into and out of these machines on wire pathways. Most of the pathways conduct electricity easily, so the electrons are free to move.

But inside the iron and the toaster, part of the pathway is made of a different kind of wire. This wire is made from a kind of metal in which the electrons don’t move very easily. Often the wire is very thin, and sometimes it is wound into a long, tight coil. Instead of conducting electricity easily, this part of the pathway resists the current. The electrons have to push hard to move through this wire.

The pushing electrons make the molecules in the wire speed up and bump into one another. The harder they bump and push, the hotter the wire gets. In a few minutes, the bumping and pushing make the wire hot. And the heat presses clothes or toasts bread.

In irons and toasters, resistance is a good thing. But in many machines, resistance is a waste of electricity. So scientists are always working to create materials that can conduct electricity without resistance. These materials are called superconductors. Someday, people may travel on high-speed trains that float on superconducting magnets. Test models of these trains have already reached speeds of more than 400 kilometres per hour.

When you turn on a lamp, electricity makes the bulb light up. How?

The electricity flows through a wire into the bulb. It travels around a wire inside the bulb. Then it leaves the bulb. Part of the electricity’s path through the bulb is a filament, a very thin thread of coiled wire. The filament is so thin that electrons have to push hard to get through.

The push of the electrons makes the molecules in the filament move faster. As the molecules speed up, they get so hot that their electrons give off energy. Then the filament glows.

The filament in the light bulb is made of metal called tungsten. A tungsten wire can get very hot without burning or melting. But as tungsten is heated, its molecules very slowly change to a gas and leave the wire. So, as the light bulb glows, the filament gets thinner and thinner.

After many hours of use, the filament breaks. The bulb is “burned out”. The electricity can’t get across the break in the filament. Then you put in a new bulb. Now the electric current has a path to follow. The lamp lights up again.

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