A shock wave is characterized by the sudden and nearly discontinuous change within different mediums.

It is caused by the tremendous rapid rise in temperature, pressure, or even with the density of the flow in the atmosphere. In a conventional supersonic flow, the expansion is attained through expansion fans.

Shockwaves always travel at much higher speeds when compared to the usual, ordinary wave. Unlike other kinds of non-linear waves, the shock wave’s energy disperses quickly as it travels. However, the approach of the accompanying expansion wave partially cancels out the energy as it merges with the shock wave. This is what causes the sonic boom which comes with the passage of any supersonic aircraft through the sound wave that results in a expansion wave merger.

Physically, shockwaves in the air are typically heard of as that loud snap or cracking noise. And over long distances, shockwaves can naturally change from non-linear waves into linear waves. This then degenerates into a sound wave conventionally as it reacts to its surroundings, heating the surrounding air thereby losing the energy. This sound wave is the normal thump or thud of the sonic boom that is commonly created in flight of a supersonic aircraft.

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The upper portion of the Earth’s atmosphere is ionized with electrons liberated by the ultraviolet light of the Sun from neutral atmospheric particles, resulting into a gas now known as plasma, which is composed of both positive and negatively charged particles.

The positively charged particles are known as ions, while the negatively charged ones are termed electrons. Electrons are very low in mass, but tend to have high levels of energy. For this reason, the Earth’s gravity soon loses hold on them and they begin to gradually escape, leaving the ions to form a growing net of positive electric charge in the ionosphere while forming their own region of negatively charged space right above it. This negatively charged space will then keep the wayward electrons from moving any further from the Earth’s atmosphere.

The electrons retain their energy, and eventually attract the remaining lighter ions of hydrogen, helium and oxygen to leave the ionosphere as well. These camaraderie of escaping particles will then build up until a balance is achieved wherein there is as much plasma that flows into the ionosphere as there is that flows without. This process of exchange between particles forms the colder region of plasma known as the plasmasphere.

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Polycyclic Aromatic Hydrocarbons

In the study of the cosmos, astronomers discovered that the processes that lead to the generation of dark clouds of dust, which are similar to sand on Earth because of the dominant presence of silicon, also produces Polycyclic Aromatic Hydrocarbons (PAHs). PAHs are the best clues that astronomers and astrophysicists use today to trace the formation of stars using the Spitzer Space Telescope. The glowing emissions of PAHs are used to light up the paths leading to dark clouds in nearby star-forming regions and help identify the entire scope of these structures. Through the vivid and precise determination of these structures, patterns of star formations and past galactic processes are recalled.

Polycyclic Aromatic Hydrocarbons (PAHs) were also found on a rock named ALH 84001, which was traced to be an object from Mars and a controversial proof that life existed on the red planet.

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Outgassing

This happens in many areas, including environments, nature and other processes. However, outgassing in astronomy specifically refers to gases released by the earth and other terrestrial planets. The earth, for instance, releases gaseous products such as helium and carbon dioxide from the mantle’s magma, in the midst of crust formation.

Outgassing can be measured by comparing gas ratios in a planet’s atmosphere. In terrestial planets, several radiogenic substances are considered to be constant. Noble gas ratios can be affected by atmospherics escape processes. It is said that on earth, outgassing efficiency is at 30-70 percent. Lesser than this would translate to lesser water present in the earth’s surface.

The release of gases by volcanoes and rocks make up for the atmosphere it is today. It’s essential past, the release of greenhouse gases contributed to maintain warming of the earth, as the sun was incapable of producing much needed heat. Alongside evolution of all living things is continuous outgassing.

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What is a telescope Lens? A telescope Lens comes in different sizes. One may find one in the form of a small plastic toy; another may find a telescope Lens that is worth millions of dollars. There are telescopes found in science laboratories all over the globe, there are telescopes in observatories, there are even telescopes built into cameras. What all these telescopes Lens have all in common is that they make what seem miles and miles away, or far away, appear much closer. How does this work?

Well, a telescopes Lens contain a refractor, or a tube that is used to change the pathway of light that comes into the telescope. The light entering is refracted, and eventually meets at a focal point. The image is then focused, and seemingly enlarged.

What are the types of Lens available? Telescope lenses are typically categorized by the shape of the lens and how curved the lens is. The basic types of lens shapes are the concave and convex. A lens that has a convex side and a concave side is a convex concave. This type of lens is the one that is made us in glasses. Other kinds exist, which are known to magnify things that are far away.

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Light pollution

Pollution happens during the production of artificial light. There are several scientific meanings of Light pollution. These include:

• Light pollution is the adjustment of light due to artificial light resources.
• Light pollution is the excessive production of artificial light which adversely affect the light levels.

All these refers to the introduction of man-made structures that produce artificial light.

What light pollution does is that it reduces the visibility in the evening sky. It does not allow people to appreciate the beauty of the heavens. It also disrupts astronomers in their study of space. Such pollution is known to distract existing ecosystems not to mention negative health effects.

This type of pollution is one of the consequences of the industrial revolution. As cities become more and more urbanized, one may observe a heightened degree of Light pollution. This is a very dangerous predicament in our ever-developing world.

What is Light Pollution?

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Luminosity can be interpreted in two ways. The most common manifestation of this event is when stars are seen at night. Stars emit light in the visible part of the electromagnetic spectrum, allowing observers to see stars by simply looking up the sky. The other manifestation is radiation and is not easily observed but still make up the total energy emitted by a star. Astronomers calculate luminosity using either a star’s apparent or bolometric magnitude.

A star’s luminosity can tell astronomers about its different characteristics. With this parameter, astronomers can quantify a star’s temperature or hotness, their size or their ability to support life just like our Sun. The energy emitted by a star greatly contributes to our present knowledge about the universe today.

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The limiting magnitude of a celestial object is greatly obscured by the presence of light pollution and sky glow in the observer’s location. These factors greatly reduce the limiting magnitude of the celestial body being observed and some of the faintest stars that comprise a constellation in the sky might not be visible. The limiting magnitude can also be used to refer to the detection of very faint stars using the naked eye near the zenith or the point directly above the observer during a moonless night sky. This brightness indicator can be used to determine the overall brightness of the sky and quantify the amount of light pollution.

Observers and amateur astronomers can make use of tables that have published values of limiting magnitude of celestial objects. If a telescope is to be used, calculating this particular value may be more convenient.

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The Van Allen belts are not distributed uniformly across earth. The part that is nearer the sun is compressed by the solar wind while in the opposite side; the belt is somewhat elongated three times the radius of earth.

The Van Allen belts contain small amounts of alpha particles. The outer Van Allen belt is composed of electrons. The number of particles, however, is not constant because of collision with other atmospheric particles. It usually extends 13,000 to 60,000 kilometers from the earth’s surface. This layer is much more diffused and bigger than the inner layer.

The inner belt extends from around 3 times the radius of earth from the surface. It contains both protons and electrons and other high energy ions found in the stronger magnetic fields.

The radiation from the Van Allen belt causes damage to many of the gadgets sent into space. Even satellites become dysfunctional when the Van Allen Belt is amplified. This can be even more dangerous to humans. Because of this, astronauts spend the smallest time possible in the radiation belt. Electronics has been modified to withstand magnetic storms.

But despite its harm on the electronics and humans sent into space, scientist believe that the Van Allen Belt protects the planet from the more hazardous solar winds and that thinning the belt will cause serious damage to the living conditions on earth.

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Not many know that it?s not just plasma TVs and plasma balls in museums which have ionized gas or plasma. When gas is ionized it specifically means gas electrons have been charged enough to let them escape atoms or molecules (positive ionization). When this happens there is always a visual manifestation no matter how slight, and they usually are spectacular to behold.

Take, for example, the inside of fluorescent lamps and neon signs, lightning, St. Elmo?s fire, and the auroras. A lot in outer space are made of plasma?the Sun, stars and solar wind, the space between stars, planets and galaxies, and nebulas. In fact it is plasma which is the most common state of matter in outer space, which only makes sense because if the stars and the space between almost everything in the universe is plasma, then that is indeed a lot of ionized gas.

Galactic Ionized Gas

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