Crab Nebula
Looking up at the night sky you see stars lying on a never-ending dark blanket. It is within this “blanket”, called the interstellar medium, that new stars are formed. The interstellar medium consists of 99% gas and about 1% dust particles. Hydrogen is the predominant gas in both atomic and molecular forms. While being the place where stars are born, the interstellar medium also creates beautiful nebulae. A reflection nebula is created when light from a nearby star reflects from the dust particles in the interstellar medium. There are two main types of nebulae and two other descriptions of what happens to the light that comes from nearby stars.
One of the main types of nebulae is called a reflection nebula. The particles around stars are about the same size as the wavelength of visible light and therefore they are able to reflect the visible light being emitted from the nearby star. However, most of the time these clouds of dust have a bluish color to them and that is due to the fact that the particles are at about the same size as the blue wavelengths and it is harder for them to interact with the longer red or orange wavelengths. The best reflections nebulae come around stars that are cooler than 25000 K. Another main type of nebula is an emission nebula and this type derives its light from the UV radiation being emitted from a nearby star. The light from the starts exites atoms in the dust cloud which in turn emit light. . When describing what happens to light coming from a star there are two things that refer to it. One would be extinction and this happens when the dust cloud around the star is so dense that the light cannot pass through it and it appears as if the light just stops or makes the star appear dimmer than it really is. Another one would be reddening and this happens when the dust particles in the interstellar medium pass the longer red or orange wavelengths. This process gives the clouds a reddish color and overpowers the blues, greens , and violets.
A supernova remnant is a cloud of gas created in the explosion of a star as a supernova. Located 6,300 light years away, the Crab Nebula (M1) is one of the most famous supernova remnants and is one of only a few historically observed supernovae in the Milky Way Galaxy. It is specifically located at right ascension 5 hour...
... middle of paper ...
... our own sun (In Context).
Some neutron stars emit radio waves, light, and other forms of radiation that appear to pulse on and off like a lighthouse beacon. Called pulsars, they only appear to turn radio waves on and off because the star is spinning. We can only pick up the radio waves when the pulsar’s beam sweeps across Earth. Their rapid rotation makes them powerful electric generators, trapping and emitting charged particles though space as radio waves. It can charge these particles up to millions of volts. The Crab pulsar, produces enough energy to power the nebula and make it expand (History).
Because a pulsar’s energy output lights up and expands the nebula around it, it loses energy from the rotation, causing it to spin slower over time. However, the rate of loss is so minimal that it will take about 10,000 years for the pulsar to slow to even half of its current speed. As time goes on, the Crab’s pulses will become less and less intense, and its X-Ray emissions will eventually end. The nebula itself will disappear after only a few thousand years, leaving only the radio pulsar to beam every few seconds (History).
The Lagoon Nebula featured as Nasa’s astronomy picture of the day was photographed by John Nemcik using various filters to capture the light emitted by the Hydrogen, Sulfur, and Oxygen. While photographed showing beautiful vibrant, eye-catching colors, the Nebula would appear naturally appear gray to human eye due to poor color sensitivity existing at low-light levels (spacetelescope.org). The Lagoon Nebula is home to the formation of new stars, as well as several other interesting phenomena such as Bok globules, and the hourglass nebula. It is these regions of the nebula that make it a continuous area of interest and study for astronomers.
When itBetelgeuse cannot fuse anymore anything over iron, the star will not have enough energy to make heat. Eventually, the core will collapse. When Betelgeuse collapses, it is so strong and powerful that it causes the outer layers to rebound. With the rebound it will have an explosion, which is called a Supernova (Type two). The explosion has so much energy and power that the temperature becomes really hot. The temperature is so hot that it can use the fusion process much heavier than iron. The elements that were given off from the explosion are sent throughout space and are now new nebula. When the Supernova is done, it has left behind a star called a Neutron star. They form when atoms of the core of a dead star are crushed together and the end result produces neutrons. The neutrons are with electrons that are degenerate on the surface. Many Neutron stars have magnetic fields and they give off strong waves of radiation from their poles. These types of Neutron Stars are known as Pulsars.
These stars are very large and therefore have very big surface areas. These large surface areas give off large amounts of light and this makes the stars bright. Most of these stars are known as red giants. Some are so large however that they are referred to as supergiants. Red giants have a temperature of about 3,500 degrees Kelvin and an absolute magnitude of around 0. Supergiants have a temperature of around 3,000 degrees Kelvin and an absolute magnitude of about -7.
In conclusion, quasars and pulsars are beautiful, powerful, and slightly terrifying, celestial formations. Quasars are black holes consuming super dense star dust and emitting faint radio signals. Pulsars are the remnants of once great stars that have lost all of their neutrons. They spin at an extremely fast rate and release high intensity beams that “pulse” in and out of view. They are both fantastic and interesting phenomenons of the universe.
Have you ever heard the phrase “We are stardust”? Chances are you have, but what exactly does that mean? As an Astronomy major and someone whose always been fascinated by the wonders of space, including the wonder of supernovas. I want to pass some of the information I have learned to you today by telling you the different types of supernova and what happens during a supernova.
Furthermore, there are five main types of nebulae; they include emission, reflection, planetary, dark and supernova remnants. Each type appears in a vast array of shapes, sizes and form in different ways. The unique appearance of each nebula depends on temperature, density and how the dust is spatially arranged with respect to the viewer. Although all nebulae are forms of interstellar matter some of them formed from the death of stars while others formed from atoms and simply reflect the light from the nearby stars.
Solar nebula is a rotating flattened disk of gas and dust in which the outer part of the disk became planets while the center bulge part became the sun. Its inner part is hot, which is heated by a young sun and due to the impact of the gas falling on the disk during its collapse. However, the outer part is cold and far below the freezing point of water. In the solar nebula, the process of condensation occurs after enough cooling of solar nebula and results in the formation into a disk. Condensation is a process of cooling the gas and its molecules stick together to form liquid or solid particles. Therefore, condensation is the change from gas to liquid. In this process, the gas must cool below a critical temperature. Accretion is the process in which the tiny condensed particles from the nebula begin to stick together to form bigger pieces. Solar nebular theory explains the formation of the solar system. In the solar nebula, tiny grains stuck together and created bigger grains that grew into clumps, possibly held together by electrical forces similar to those that make lint stick to your clothes. Subsequent collisions, if not too violent, allowed these smaller particles to grow into objects ranging in size from millimeters to kilometers. These larger objects are called planetesimals. As planetesimals moved within the disk and collide with one another, planets formed. Because astronomers have no direct way to observe how the Solar System formed, they rely heavily on computer simulations to study that remote time. Computer simulations try to solve Newton’s laws of motion for the complex mix of dust and gas that we believe made up the solar nebula. Merging of the planetesimals increased their mass and thus their gravitational attraction. That, in turn, helped them grow even more massive by drawing planetesimals into clumps or rings around the sun. The process of planets building undergoes consumption of most of the planetesimals. Some survived planetesimals form small moons, asteroids, and comets. The leftover Rocky planetesimals that remained between Jupiter and Mars were stirred by Jupiter’s gravitational force. Therefore, these Rocky planetesimals are unable to assemble into a planet. These planetesimals are known as asteroids. Formation of solar system is explained by solar nebular theory. A rotating flat disk with center bulge is the solar nebula. The outer part of the disk becomes planets and the center bulge becomes the sun.
Stars are born and reborn from an explosion of a previous star. The particles and helium are brought together the same way the last star was born. Throughout the life of a star, it manages to avoid collapsing. The gravitational pull from the core of the star has to equal the gravitational pull of the gasses, which form a type of orbit. When this equality is broken, the star can go into several different stages. Some stars that are at least thirty times larger than our sun can form black holes and other kinds of stars.
A supernova is an explosion of a massive supergiant star. It may shine with a brightness of 10 billion suns! The total energy output may be 10^44 joules, as much as the total output of the sun during its 10 billion year lifetime. The likely scenario is fusion proceeds to build up a core of iron. The “iron group” of elements around mass number A=60 are the most tightly bound nuclei, so no more energy can be gotten from nuclear fusion. Supernovas are classified at Type one if their light curves exhibit sharp maxima and then die away gradually. The maxima may be about 10 billion solar luminosities. Type two supernovas have less sharp peaks at maxima and peak at about 1 billion solar luminosities. They die away more sharply than Type one. Type two supernovas are not observed to occur in elliptical galaxies, and are thought to occur in population one type stars in the spiral arms of galaxies. Type one supernovas occur typically occur in elliptical galaxies, so they are probably Population type two stars. With the observation of a number of supernovas in other galaxies a more refined classification of supernovas has been developed based on the observed spectra. Th...
If the nebula is dense enough, certain regions of it will begin to gravitationally collapse after being disturbed. As it collapses the particles begin to move more rapidly, which on a molecular level is actually heat, and photons are emitted that drive off the remaining dust and gas. Once the cloud has collapsed enough to cause the core temperature to reach ten-million degrees Celsius, nuclear fusion starts in its core and this ball of gas and dust is now a star. It begins its life as a main sequence star and little does it know its entire life has already been predetermined.
All galaxies contain star clusters. A star cluster is a group of stars held together by gravity. Open star clusters are collections of six to thousands of usually young stars. Globular clusters are ball-shaped collections of thousands to millions of very old stars. Galaxies are collections of millions to hundreds of billions of stars, planets, gas, and dust, measuring up to one hundred thousand ly across. They came in different shapes and sizes and are spread across the Universe. In the 1920’s, astronomer Edwin Hubble changed the way in which scientists view the Universe. The four types of galaxies that are categorized by shape are elliptical, spiral, lenticular, and irregular. Elliptical galaxy is a large group of stars that together make
A star begins as nothing more than a very light distribution of interstellar gases and dust particles over a distance of a few dozen lightyears. Although there is extremely low pressure existing between stars, this distribution of gas exists instead of a true vacuum. If the density of gas becomes larger than .1 particles per cubic centimeter, the interstellar gas grows unstable. Any small deviation in density, and because it is impossible to have a perfectly even distribution in these clouds this is something that will naturally occur, and the area begins to contract. This happens because between about .1 and 1 particles per cubic centimeter, pressure gains an inverse relationship with density. This causes internal pressure to decrease with increasing density, which because of the higher external pressure, causes the density to continue to increase. This causes the gas in the interstellar medium to spontaneously collect into denser clouds. The denser clouds will contain molecular hydrogen (H2) and interstellar dust particles including carbon compounds, silicates, and small impure ice crystals. Also, within these clouds, there are 2 types of zones. There are H I zones, which contain neutral hydrogen and often have a temperature around 100 Kelvin (K), and there are H II zones, which contain ionized hydrogen and have a temperature around 10,000 K. The ionized hydrogen absorbs ultraviolet light from it’s environment and retransmits it as visible and infrared light. These clouds, visible to the human eye, have been named nebulae. The density in these nebulae is usually about 10 atoms per cubic centimeter. In brighter nebulae, there exists densities of up to several thousand atoms per cubic centimete...
The Orion Nebula is an emission nebula because of the O-type and B-type stars contained within it. These high-temperature stars emit ultraviolet (UV) light that ionizes the surrounding hydrogen atoms into protons (H+) and electrons (e-). When the protons and electrons recombine, the electrons enter a higher energy level (n=3). Then, when the electron drops from the n=3 level to the n=2 level, an Hphoton is emitted. 2 This photon has a wavelength of 6563 Å, and therefore corresponds to the red portion of the visible spectrum. It is these H photons which give the nebula the distinctive red color which we see.
Astronomers believe that most galaxies consist of a supermassive black hole at the center, which attracts all constituents of galaxies such as, dust, gases (mainly Hydrogen and Helium), atoms, stars, interstellar clouds and planets to the center by force of gravity, but are not sure whether all galaxies contain a black hole in the center. Galaxies keep moving in relative motion to one another and intermittently can come so close that the force of gravitational attraction between the galaxies may become strong enough to cause a change in the shape of the galaxies, while in exceptional cases, the galaxies may collide. If two galaxies collide, they may pass right through without any effect or may merge, forming strands of stars, extending beyond 100,000 light years in space (World Book Online Reference Centre, 2005). Hence, neighboring and often other colliding galaxies induce the sha...
The idea behind the Solar Nebular Hypothesis is that the solar system was condensed from an enormous cloud of hydrogen, helium, and a few other elements and rocks. Around five billion years this cloud of materials began to spin and contract together into a disk shape under their own gravitational forces. The particles started combined together, protoplanets, to eventually form planets. A great mass of the material eventually began to form together, protosun, and make up the sun.