Nucleosynthesis is the physical process where lighter elements are changed into heavier elements. This usually happens in the center of a star, both during its life and especially during its violent death. It is also thought that this happened at the beginning of the universe, in the big bang.
Stellar wind
Stellar wind is gas being thrown off from the upper atmosphere of a star. Different types of stars have different types of stellar winds. The Sun's stellar wind is called solar wind. Most stars, especially very bright ones, show continuous outflows of gas from their surfaces making the stellar wind. Radiation pressure is thought to be the main force that pushes the gas away, but modern research uses computer simulations and observations with the most powerful telescopes to understand it further.
Dumbbell nebula
The Dumbbell nebula (sometimes called Messier 27, M 27, or NGC 6853) is a planetary nebula in the constellation Vulpecula. It is about 1,360 light years away from earth. The Dumbbell nebula was the first planetary nebula to be discovered; by Charles Messier in 1764.
Charles Messier
Charles Messier (June 26, 1730 – April 12, 1817) was a French astronomer who is remembered for publishing a list of famous objects in space that came to be called the 103 "Messier objects".
Messier was born in Badonviller in the Lorraine region of France. Six of his brothers and sisters died as children and in 1741, his father died. Charles became interested in astronomy after he saw the great six-tailed comet in 1744 and by a solar eclipse on July 25, 1748.
In 1751 he started working for Joseph Nicolas Delisle, the astronomer of the French Navy, who told him to write down everything he saw.
Messier discovered thirteen comets :
Astronomical spectroscopy
Astronomical spectroscopy is the science of using spectroscopy to figure out what elements astronomical bodies, such as stars, planets and nebulae, are made of. It can also be used to work out how those objects are moving, using doppler shift.
The study of spectroscopy and spectra is used in astronomy to help scientists study the whole spectrum of electromagnetic radiation, including visible light, which radiates from stars and other hot celestial objects. Spectroscopy can be used to find properties of distant stars and galaxies. It can find out their chemical composition, temperature, density, mass, distance, luminosity, and relative motion using doppler effect measurements.
Isaac Newton used a prism to split white light into a spectrum of color, and Fraunhofer's high-quality prisms allowed scientists to see dark lines of an unknown origin.
It was not until the 1850s that Gustav Kirchoff and Robert Bunsen explained the dark lines. Hot solid objects produce light with a continuous spectrum, and hot gasses emit light at specific wavelengths. However, hot solid objects surrounded by cooler gasses show a near-continuous spectrum with "dark lines corresponding to the emission lines of the gasses". By comparing the absorption lines of the
Sun with emission spectra of known gasses, the chemical composition of stars can be discovered.
William Huggins
Sir William Huggins, KCB, OM, FRS, (7 February 1824–12 May 1910) was an English astronomer best known for his work in astronomical spectroscopy.
William Huggins was born at Cornhill, Middlesex in 1824. He married Margaret Lindsay, who was also an astronomer.
Huggins built his own observatory from where he and his wife looked at spectral emission lines and absorption lines of astronomical objects. He was the first person to figure out the difference between nebulae and galaxies.
Huggins was president of the Royal Society between 1900 and 1905.
Emission spectrum
The emission spectrum of an element or compound is how bright certain frequencies are when energy is added to the atoms or molecules.
Each atom's emission spectrum has different spectral lines and can be used to figure out if that atom is part of a compound
Luminosity
Luminosity is the amount of power given off by an astronomical object.
Stars, galaxies and other objects emit energy in the form of radiation. It is measured in joules per second, which are equal to watts. A watt is one unit of power. Just as a light bulb is measured in watts, the Sun can also be measured in watts. The sun gives off . This amount of power is known as 1 sol, the symbol for which is formula_1.
There are other ways to describe luminosity. The most common is apparent magnitude, which is how bright an object looks to an observer on Earth. It only applies to light, that is, visible wavelengths. Apparent magnitude is contrasted with absolute magnitude, which is an object's "intrinsic brightness" at visible wavelengths, irrespective of distance. The apparent magnitude is the less, for objects more than 32.6 light years away.
When talking about the total power output across all wavelengths, that is called bolometric magnitude.
Solar mass
Solar mass is a unit of measurement of mass. It is equal to the mass of the Sun, about 332,950 times the mass of the Earth, or 1,048 times the mass of Jupiter. Masses of other stars and groups of stars are listed in terms of solar masses. Its mathematical symbol and value are:
Interstellar medium
In astronomy, the interstellar medium (sometimes called the ISM) is the tenuous gas and dust that fills the void between stellar systems in galaxies, that consisting mainly of huge clouds of ionized, netral, or moleculer hydrogen. This gas and dust not distributed uniformly in interstellar space, but displays significant variations in density, temperature, and ionization state.
Various gases exist in outer space. Most common are hydrogen and helium. Interstellar cosmic dust makes nebulae.
Myopia
Myopia, also called near-sightedness or short-sightedness, is a problem with the focusing ability of the eye. It is when the eye is not able to focus properly on objects in the distance. This condition is very common and it often occurs with many members of the same family. It happens when the lens becomes a different shape (too curved) from usual, or when the eye is longer than normal, so light entering the eye focuses on a point "in front of" the retina, rather than right on it. This makes distant objects look blurry. People with myopia often squint while watching television or trying to see distant objects. Sudden myopia can often be the first symptom of Type II Diabetes.
In most cases, it can be fixed easily using glasses, contact lenses, or surgery.
Luster (mineralogy)
Luster (or lustre) is a description of the way light interacts with the surface of a crystal, rock, or mineral. For example, a diamond has an adamantine lustre and pyrite has a metallic lustre. The term is also used to describe other items with some kind of sheen (for example, fabric, especially silk and satin, or metals).
The word lustre comes from the Latin word lux, meaning "light", and generally implies radiance, gloss, or brilliance.
Carbonation
Carbonation is the process of carbon dioxide dissolving in a liquid. For example, carbon dioxide is added to flavored water under pressure to make it "fizz" as a carbonated water soft drink.
When rain passes through the atmosphere, it takes in or mixes with carbon dioxide, turning it into a weak carbonic acid. When the rain falls in limestone, it dissolves the calcium carbonate in the rock, turning it into calcium bicarbonate and taking it away. Holes and large cracks can form in the rock. Such a place is called karst. If a stream or river passes through it, it could be swallowed up by a hole called a swallow hole. It can go through a series of underground caves and may appear on the surface again. An example of a karst area is the Burren National Park, in County Clare, Ireland.