Space Agencies Go For Jupiter and Saturn

 

NASA and the European Space Agency have decided to go ahead with an ambitious plan to send a probe to Jupiter and its icy moon Europa. A further project would involve the two agencies to send a spacecraft to Saturn’s moon Titan.

David Southwood, ESA’s Director of Science says that the joint venture is a wonderful new challenge and it will be a milestone of 21 st century space exploration. The Jupiter mission has been chosen to start because it is the more realistic project.

Scientists have been dreaming of visiting Europa for a long time. The icy moon may have underground water and researchers want to find out if such a satellite may be fit for life. It is surely one of the places in the solar system where life might have evolved some time ago.

The project calls for NASA to send an orbiter to Europa and ESA to send one to Jupiter’s moon Ganymede. Both spacecraft would be launched in 2020, but from two separate launch sites. They would reach Jupiter by 2026 and examine the moons for the following three years. Although the two spacecraft would observe Europa from different positions only the NASA probe would spend time in Europa’s orbit.

The moon is said to have a strong radiation field and orbiting it would only be possible for a few months. NASA plans to use special equipment to protect its probe. The two probes would end their mission by crashing into the moons they are orbiting around.

British scientists and engineers will play key roles in the joint mission. A consortium is planning to prepare probes with instruments that would be dropped onto Europa’s surface. Thus, it could determine temperatures under the surface or locate magnetic and radiation fields.

 

Galileo Galilei

Galileo is often called the founder of modern science. He made many discoveries in astronomy and physics and he built telescopes to study space.

Galileo Galilei was born in Pisa, Italy in 1564. His father sent him to the university to study medicine, but young Galileo was more interested in science and mathematics.

Galileo made one of his greatest discoveries as he sat in a cathedral of Pisa. As he watched a chandelier swing back and forth he noticed that longer and shorter swings took the same time. This discovery became known as the law of the pendulum. These and other important discoveries made him so well-known that Galileo became a professor at the University of Pisa.

 Galileo often questioned scientific facts of his age. For a long time people thought that heavier objects fall to Earth faster than lighter ones. By dropping objects of the same size but different weights from the Leaning Tower of Pisa Galileo showed that this wasn’t true.

 In 1609 Galileo constructed his first telescope. He used it to observe the stars and the planets. He saw things that nobody had ever seen before. Galileo discovered that the moon’s surface was not smooth and flat, like everyone thought, but had a rough surface and was full of craters.

In January 1610 Galileo discovered 4 moons revolving around the Jupiter. They were named after him, the Galilean moons. These observations proved that not the Earth was the centre of the solar system, but the sun. It was a discovery that Copernicus had made 60 years earlier.

The Roman Catholic Church did not always like what Galileo taught. It still believed that the Earth was the centre of the universe and everything revolved around it. The church ordered him not to teach such ideas any more.

In 1633 Galileo was brought before the Inquisition, the Church’s court. It sentenced him to life in prison because of his teachings. Galileo was put under house arrest because he was old and not so healthy any more. He spent the last years of his life in Florence, where he continued to work on his theories and even published a final book. He became blind and died in 1642.

In 1992 Pope John Paul II published a document that said the Church made a mistake by condemning Galileo.

Albert Einstein

 Albert Einstein - Life and DiscoveriesAlbert Einstein - Life and Discoverie

Albert Einstein

Albert Einstein was a famous scientist who completely changed the way that people saw our world and the universe. Einstein created many theories which proved that things like gravity , light, energy and matter were connected with each other. At first, very few scientists could understand Einstein’s theories but as time passed other scientists showed that he was correct.

Albert Einstein was born in Ulm, Germany in 1879 and grew up in Munich. He wasn’t a good student at school and only did things he was interested in, like science and mathematics. At a very early age young Albert started wondering about the mysteries of the universe.

After school Einstein went to Switzerland and tried to become a teacher there, but he couldn’t find a job. He went to work at the Swiss patent office in Bern where he studied what other people had invented .

After divorce from his first wife, a classmate of his, Albert went to Berlin where he married his cousin Elsa. He lived in Berlin for a long time and there he developed many of his scientific theories. Einstein became so well known that he was invited to universities around the world to talk about his discoveries . In 1921 he received the Nobel Prize for Physics.

In the meantime things were starting to change in Germany. Einstein was against the Nazis and their ideas of controlling the world and killing Jews. The Nazis, in return, hated him and his theories and they burned most of his books.

Einstein decided to leave Germany and go to the United States. When World War II broke out in 1939 Einstein discovered that German scientists were working on a bomb that could kill thousands of people. He wrote a letter to the American president to warn him and suggested that the Americans start building one too.

In 1941 the American government started the Manhattan Project which led to the construction of the atomic bomb. Two of these bombs were dropped over Hiroshima and Nagasaki to end the war against Japan. Einstein was horrified when he heard the news. He wanted the world to use atomic energy for peaceful purposes .

For the last twenty years of his life, Einstein lived in Princeton where he continued his scientific work. He died on April 18, 1955

One of the most famous equations ever written came from Albert Einstein : E = mc 2 . Energy is mass times the squared speed of light. This equation shows that mass can be turned to energy. Because the speed of light square is such a high number even a small amount of mass can be turned into a lot of energy.

This means, for example, that there is enough energy in a glass of water to give power to a city like London for a whole week. The problem is how to get the energy out of the mass . This equation led to the building of the atomic bomb. The first bomb only had 0.6 grams of mass but scientist turned it into enough energy to destroy a whole city.

 Einstein also thought that space and time were closely related to each other. He thought that there were not three dimensions to objects but four—the fourth one was time. Other scientists, who continued his work, claimed that it is possible to travel into the past and into the future. Black holes might be tunnels that could take you back and forth in time .

According to Einstein all objects followed curved paths and get attracted by the gravity of an object. Time would pass more slowly if you are close to a very large object like a planet. This means that the clock of a plane goes faster than a clock at an airport because the plane is farther away from the earth.

Temperature inversion

 Temperature inversion layers, also called thermal inversions or just inversion layers, are areas where the normal decrease in air temperature with increasing altitude is reversed and the air above the ground is warmer than the air below it. Inversion layers can occur anywhere from close to ground level up to thousands of feet into the atmosphere.

Inversion layers are significant to meteorology because they block atmospheric flow which causes the air over an area experiencing an inversion to become stable. This can then result in various types of weather patterns.

More importantly, though, areas with heavy pollution are prone to unhealthy air and an increase in smog when an inversion is present because they trap pollutants at ground level instead of circulating them away.

Causes

Normally, air temperature decreases at a rate of 3.5°F for every 1,000 feet (or roughly 6.4°C for every kilometer) you climb into the atmosphere. When this normal cycle is present, it is considered an unstable air mass, and air constantly flows between the warm and cool areas. The air is better able to mix and spread around pollutants.

During an inversion episode, temperatures increase with increasing altitude. The warm inversion layer then acts as a cap and stops atmospheric mixing. This is why inversion layers are called stable air masses.

Temperature inversions are a result of other weather conditions in an area. They occur most often when a warm, less dense air mass moves over a dense, cold air mass.

This can happen, for example, when the air near the ground rapidly loses its heat on a clear night. The ground becomes cooled quickly while the air above it retains the heat the ground was holding during the day.

Temperature inversions also occur in some coastal areas because upwelling of cold water can decrease surface air temperature and the cold air mass stays under warmer ones.

Topography can also play a role in creating a temperature inversion since it can sometimes cause cold air to flow from mountain peaks down into valleys. This cold air then pushes under the warmer air rising from the valley, creating the inversion.

In addition, inversions can also form in areas with significant snow cover because the snow at ground level is cold and its white color reflects almost all heat coming in. Thus, the air above the snow is often warmer because it holds the reflected energy.

Consequences

Some of the most significant consequences of temperature inversions are the extreme weather conditions they can sometimes create. One example is freezing rain.

This phenomenon develops with a temperature inversion in a cold area because snow melts as it moves through the warm inversion layer. The precipitation then continues to fall and passes through the cold layer of air near the ground.

When it moves through this final cold air mass it becomes "super-cooled" (cooled below freezing without becoming solid.) The supercooled drops then become ice when they land on items like cars and trees and the result is freezing rain or an ice storm.

Intense thunderstorms and tornadoes are also associated with inversions because of the intense energy that is released after an inversion blocks an area’s normal convection patterns.

Effects of Acid Rain

 

Effects of Acid Rain

After studying the Hubbard Brook Forest and other areas, researchers found several important effects of acid deposition on both natural and man-made environments. Aquatic settings are the most clearly affected by acid deposition, however, because acidic precipitation falls directly into them. Both dry and wet deposition also runs off from forests, fields, and roads and flows into lakes, rivers, and streams.

As this acidic liquid flows into larger bodies of water, it is diluted. Howvever, over time, acids can accrue and lower the overall pH of the body of water. Acid deposition also causes clay soils to release aluminum and magnesium, further lowering the pH in some areas. If the pH of a lake drops below 4.8, its plants and animals risk death. It is estimated that around 50,000 lakes in the United States and Canada have a pH below normal (about 5.3 for water). Several hundred of these have a pH too low to support any aquatic life.

Aside from aquatic bodies, acid deposition can significantly affect forests. As acid rain falls on trees, it can make them lose their leaves, damage their bark, and stunt their growth. By damaging these parts of the tree, it makes them vulnerable to disease, extreme weather, and insects. Acid falling on a forest’s soil is also harmful because it disrupts soil nutrients, kills microorganisms in the soil, and can sometimes cause a calcium deficiency. Trees at high altitudes are also susceptible to problems induced by acidic cloud cover as the moisture in the clouds blankets them.

Damage to forests by acid rain is seen all over the world, but the most advanced cases are in Eastern Europe. It’s estimated that in Germany and Poland, half of the forests are damaged, while 30 percent in Switzerland have been affected.

Finally, acid deposition also has an effect on architecture and art because of its ability to corrode certain materials. As acid lands on buildings (especially those constructed with limestone), it reacts with minerals in the stones, sometimes causing them to disintegrate and wash away. Acid deposition can also cause concrete to deteriorate, and it can corrode modern buildings, cars, railroad tracks, airplanes, steel bridges, and pipes above and below ground.

What's Being Done?

Because of these problems and the adverse effects of air pollution has on human health, a number of steps are being taken to reduce sulfur and nitrogen emissions. Most notably, many governments are now requiring energy producers to clean smokestacks with scrubbers that trap pollutants before they are released into the atmosphere and to reduce car emissions with catalytic converters. Additionally, alternative energy sources are gaining more prominence and funding is being put toward the restoration of ecosystems damaged by acid rain worldwide.

Acid rain

Acid rain

 Acid rain is made up of water droplets that are unusually acidic because of atmospheric pollution, most notably the excessive amounts of sulfur and nitrogen released by cars and industrial processes. Acid rain is also called acid deposition because this term includes other forms of acidic precipitation (such as snow).

Acidic deposition occurs in two ways: wet and dry. Wet deposition is any form of precipitation that removes acids from the atmosphere and deposits them on Earth’s surface. Dry deposition polluting particles and gases stick to the ground via dust and smoke in the absence of precipitation. Even though dry, this form of deposition is dangerous as well, because precipitation can eventually wash pollutants into streams, lakes, and rivers.

Acidity itself is determined based on the pH level (the amount of acidity or alkalinity) of the water droplets. The pH scale ranges from 0 to 14, with a lower pH being more acidic, while a high pH is alkaline, and seven is neutral. Normal rainwater is slightly acidic, with a pH range of 5.3-6.0. Acid deposition is anything below that range. It is also important to note that the pH scale is logarithmic, and each whole number on the scale represents a 10-fold change.

Today, acid deposition is present in the northeastern United States, southeastern Canada, and much of Europe, including portions of Sweden, Norway, and Germany. In addition, parts of South Asia (particularly China, Sri Lanka, and southern India) and South Africa are all in danger of being affected by acid deposition in the future.

What Causes Acid Rain?

Acid deposition can be caused by natural sources such as volcanoes, but it is mainly caused by the release of sulfur dioxide and nitrogen oxide during fossil fuel combustion. When these gases are discharged into the atmosphere, they react with the water, oxygen, and other gases already present there to form sulfuric acid, ammonium nitrate, and nitric acid. These acids then disperse over large areas because of wind patterns and fall back to the ground as acid rain or other forms of precipitation.

The gases most responsible for acid deposition are a byproduct of electric power generation and the burning of coal. As such, man-made acid deposition began becoming a significant issue during the Industrial Revolution and was first discovered by a Scottish chemist Robert Angus Smith in 1852. In that year, he discovered the relationship between acid rain and atmospheric pollution in Manchester, England.

Although it was discovered in the 1800s, acid deposition did not gain significant public attention until the 1960s, and the term "acid rain" was coined in 1972. Public attention further increased in the 1970s when the "New York Times" published reports about problems occurring in the Hubbard Brook Experimental Forest in New Hampshire.

Branches of Physics

 

Branches of Physics

The physical universe has many moving parts and is not simply what is observed through the naked eye. Physics is also how the most prominent objects interact with the smallest and everything in between. Since physics is such a broad subject, it has to be broken into smaller categories or disciplines, also known as fields of study.

There are three main categories of modern physical study:

1. Classical physics covers electromagnetism, classical mechanics, thermodynamics, and statistical mechanics. Classic physics provides action and reaction, showing how objects acting in a system will interact with other objects in that same system.
2. Relativity has two types of study; there is general and specific relativity. General relativity deals with how the law of gravity interacts with objects; this has a significant bearing in astrophysics and astronomy. Special relativity concerns how objects interact in a vacuum or are devoid of gravity.
3. Quantum physics is the most recent course of study in physics. Here, scientists study quantum mechanics, quantum statistics, quantum electrodynamics, and quantum field theory. This branch deals primarily with objects at an atomic and subatomic level. It answers questions like, "what makes a proton different from a neutron?"

Mechanics

The study of mechanics is both broad and specific. Broadly, mechanics study objects, their motion, energy, and how they interact with other objects and energy. There are two sub-branches of mechanics, quantum mechanics and classical mechanics.

• Quantum mechanics, studies how atom and subatomic particles act and react with one another; similar to how the atom is held together, what happens if two atoms collide? What makes up the atomic particles; how and why do two atoms bond; what holds together millions of atoms into a complex compound?
• Classical mechanics follows the same principles as quantum, at a much larger scale. Examples of classical mechanics would be predicting planetary orbits or the path of a bullet, black holes, friction between a car tire and the road, why water has surface tension, or the arc of a baseball as it is thrown across home plate.

Mechanics can explain a minor interaction, like why an electron is attracted to a proton, and the most significant interaction, like why the earth orbits the sun.

Optics

One of our two most important senses is that of sight. In physics, the study of light and its properties is called optics.

One reason light is a fascinating study subject is that it contains the properties of a wave and particles. Additionally, electromagnetic waves make up light, meaning it has properties of electricity and magnetism and does not need a medium to move.

There are several different types of light:

• Visible
• Ultraviolet
• Infrared
• X-ray
• Radio Waves
• Gamma Rays