How Did We Get Here?

Astronomers cannot see all the way back in time to the origin of the universe, but by drawing on lots of clues and theory, they can imagine how everything began.  Their model starts with the entire universe as a very hot dot, much smaller than the diameter of an atom. The dot began to expand faster than the speed of light, an expansion called the Big Bang. Cosmologists are still arguing about the exact mechanism that may have set...

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Flawed Gravity, or Relaxing the Grip

For almost a century, Albert Einstein’s Theory of General Relativity has reigned as the explanation for how gravity works. Einstein’s equations showed that gravity is a property of matter, and that matter "warps" the space-time around it. Yet there are both problems with General Relativity and questions about its effects. "Perhaps we see the acceleration of the universe and we attribute that to energy, but maybe our theory of gravity...

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New Physics, or Particles and Fields

Scientists have discovered a menagerie of particles, and suspect that the universe contains many more — perhaps including particles of dark energy and dark matter.  Physicists have observed lots of particles in the universe: the protons, neutrons, and electrons that make up atoms; the quarks that make up protons and neutrons; and particles with such exotic names as muons, leptons, and neutrinos. At the same time, they have observed...

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Vacuum Energy, or Einstein’s Blunder

1. Empty space. 2. Two particles suddenly appear. 3. Particles ram together and annihilate each other. 4. They leave ripples of energy through space. If Las Vegas were taking bets on dark energy, the odds would favor a concept known as vacuum energy or the cosmological constant. In essence, it suggests that space itself produces energy, which is "pushing" the universe outward. Albert Einstein invented the cosmological constant as...

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What is dark energy?

Like the "dark side of the Moon," dark energy represents the unknown. In the late 1990s, astronomers discovered that the universe is expanding faster today than they had expected. But they don’t know what is causing the acceleration, so for now, they simply call it "dark energy." "Dark energy is our ignorance of what’s going on in the universe right now," says Karl Gebhardt, a professor of astronomy at The University of Texas...

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Father of modern Astronomy

Father of Astronomy :- Galileo Galilei Galileo Galilei Galileo Galilei, was an Italian physicist, mathematician, astronomer, and philosopher who played a major role in the Scientific Revolution. Galileo, known by his first name only, was an astronomer, inventor, Physicist and mathematician. He was born February 15, 1564 in Pisa, to a father, who was a famous lutanist ( lute is a stringed instrument with a pear shaped body )...

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Who Invented the Rocket?

Although the Chinese are credited with having invented the rocket as early as the 3rd Century AD, it was not until the 20th Century that it began to take on its modern form. For that, we can thank a Russian mathematician, an American professor, and an Austro-Hungarian physicist. Who Invented the Rocket? Konstantin Tsiolkovsky, Robert Goddard, Hermann Oberth In 1903, Konstantin Tsiolkovsky published a seminal work, The Exploration...

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A Brief History of Animals in Space

Before humans actually went into space, one of the prevailing theories of the perils of space flight was that humans might not be able to survive long periods of weightlessness. For several years, there had been a serious debate among scientists about the effects of prolonged weightlessness. American and Russian scientists utilized animals - mainly monkeys, chimps and dogs - in order to test each country's ability to launch a living organism...

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Who Was the First Astronaut?

The first astronaut was either the Soviet Yuri Gagarin or the Soviet dog Laika, depending on whether the definition is restricted based on species. Both are remembered for their accomplishments and contributions to space travel. Laika, a name that literally means "barker" and was based on her breed, was launched into space on 3 November 1957 on board Sputnik 2, becoming the first animal to orbit the Earth. This took place only a month after the first satellite, Sputnik, was launched, on 4 October...

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What causes gravitational force in the universe?

Gravity is one the four fundamental forces of the universe and is considered a noncontact force. It is what holds the planets in orbit as well as the very universe itself. It is what keeps us from floating off into space and plays a crucial role in almost every nature process from the ocean tides to the body’s circulatory system. However what causes gravity? What is the mechanism that makes it work? Physicists have only partially answered...

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Universal Law of Gravitation

One of Sir Issac Newton’s biggest contributions to physics and the larger body of science was the universal law of gravitation. Without it we can’t explain the classical motion of objects on Earth or in space. We would not have gained the ability to fly or even go into space. The understanding of gravity is basically the beggining of understanding classical mechanics and physics. The story of how Sir Isaac Newton has now become one...

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Is it Safe to Be Around Sources of Radiation? How Can You Work Safely Around Radiation or Contamination?

How Can You Work Safely Around Radiation or Contamination? You can work safely around radiation and/or contamination by following a few simple precautions: Use time, distance, shielding, and containment to reduce exposure.  Wear dosimeters (e.g., film or TLD badges) if issued.  Avoid contact with the contamination.  Wear protective clothing that, if contaminated, can be removed.  Wash with nonabrasive soap and water any part of the body that may have come in contact with the contamination.  Assume...

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How Can You Detect Radiation?

Radiation cannot be detected by human senses. A variety of handheld and laboratory instruments is available for detecting and measuring radiation. The most common handheld or portable instruments are: Geiger Counter, with Geiger-Mueller (G-M) Tube or Probe — A G-M tube is a gas-filled device that, when a high voltage is applied, creates an electrical pulse when radiation interacts with the wall or gas in the tube. These pulses...

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