what is the emission spectrum of the sun?
101595
it is a series of lines, due primarily to the presence of hydrogen and helium and to lesser extent carbon, nitrogen and a few others. the most important lines show up in the visible part of the EM spectrum.
541140
Well if you look at the spectrum of a star you'll see a smooth continuum as well as the spectral lines.  Those lines are either absorbtion lines or emission lines of such things as Hydrogen, Helium, Calcium, Iron and a whole heap of others and we know the wavelength of those lines very well so by comparing what we measure them to be with what we have determined in the lab we can calculate how fast the star is moving towards or away us (radial velocity).\n\nThen once we know the radial velocity we just measure where the peak in the continuum is, correct for the radial velocity to find what the wavelength where the emission actually peaks and then since the star is very close to a blackbody we can calculate the temperature (a blackbody of a given temperature will peak at a given wavelength).
420114
Isolated atoms can absorb and emit packets of electromagnetic radiation having discrete energies dictated by the detailed atomic structure of the atoms. When the corresponding light is passed through a prism or spectrograph it is separated spatially according to wavelength.\n\nThe corresponding spectrum may exhibit a continuum, or may have superposed on the continuum bright lines (an emission spectrum) or dark lines (an absorption spectrum). \n\nThus, emission spectra are produced by thin gases in which the atoms do not experience many collisions (because of the low density). The emission lines correspond to photons of discrete energies that are emitted when excited atomic states in the gas make transitions back to lower-lying levels.\n\nAn absorption spectrum occurs when light passes through a cold, dilute gas and atoms in the gas absorb at characteristic frequencies; since the re-emitted light is unlikely to be emitted in the same direction as the absorbed photon, this gives rise to dark lines (absence of light) in the spectrum.
477826
heat is not electromagnetic radiation, it's molecular kinetic energy (or thermal energy).  The sun emits Ultraviolet radiation, amongst other emissions in the light spectra, but i don't believe the heat emitted can be attributed to an electromagnetic wave.
247428
that we can see?  The sun.
55579
The sun is a giant ball of plasma constantly fusing hydrogen into helium.  It is not 'on fire', so to speak, so the lack of oxygen and the coldness of space don't effect it like a match or something.
396592
A continuous spectrum of what?
905102
A material's emission spectrum is the amount of electromagnetic radiation of each frequency it emits when it is heated (or more generally when it is excited).\n\nWhen the electrons in the element are excited, they jump to higher energy levels. As the electrons fall back down, and leave the excited state, energy is re-emitted, the wavelength of which refers to the discrete lines of the emission spectrum. Note however that the emission extends over a range of frequencies, an effect called spectral line broadening.\n\nThe term often refers to the visible light emission spectrum, although it extends to the whole electromagnetic spectrum, from the low energy radio waves up to high energy gamma rays.\n\nThe emission spectrum can be used to determine the composition of a material, since it is different for each element of the periodic table. One example is identifying the composition of stars by analysing the received light.
619304
You asked for it! Ha ha ha ha!\n\nWhat is the sun? Read this.....\nI  INTRODUCTION \n\nSun, closest star to Earth. The Sun is a huge mass of hot, glowing gas. The strong gravitational pull of the Sun holds Earth and the other planets in the solar system in orbit. The Sun’s light and heat influence all of the objects in the solar system and allow life to exist on Earth. \n\nThe Sun is an average star—its size, age, and temperature fall in about the middle of the ranges of these properties for all stars. Astronomers believe that the Sun is about 4.6 billion years old and will keep shining for about another 7 billion years. \n\nFor humans, the Sun is beautiful and useful, but also powerful and dangerous. As Earth turns, the Sun rises over the eastern horizon in the morning, passes across the sky during the day, and sets in the west in the evening. This movement of the Sun across the sky marks the passage of time during the day (see Sundial). The Sun’s movement can produce spectacular sunrises and sunsets under the right atmospheric conditions. At night, reflected sunlight makes the Moon and planets bright in the night sky. \n\nThe Sun provides Earth with vast amounts of energy every day. The oceans and seas store this energy and help keep the temperature of Earth at a level that allows a wide variety of life to exist. Plants use the Sun’s energy to make food, and plants provide food for other organisms. The Sun’s energy also creates wind in Earth’s atmosphere. This wind can be harnessed and used to produce power.\n\nWhile it lights our day and provides energy for life, sunlight can also be harmful to people. Human skin is sensitive to ultraviolet light emitted from the Sun. Earth’s atmosphere blocks much of the harmful light, but sunlight is still strong enough to burn skin under some conditions (see Burn). Sunburn is one of the most important risk factors in the development of skin cancers, which can be fatal. Sunlight is also very harmful to human eyes. A person should never look directly at the Sun, even with sunglasses or during an eclipse. The Sun influences Earth with more than just light. Particles flowing from the Sun can disrupt Earth’s magnetic field, and these disruptions can interfere with electronic communications.\n\nII  PHYSICAL CHARACTERISTICS \n\nThe Sun is large and massive compared to the other objects in the solar system. The Sun’s radius (the distance from its center to its surface) is 695,508 km (432,169 mi), 109 times as large as Earth’s radius. If the Sun were hollow, a million Earths could fit inside it. The Sun has a mass of 1.989 × 1027 metric tons. This number is very large. Written out, it would be the digits 1989 followed by 24 zeroes. The Sun is 333,000 times as massive as Earth is. Despite its large mass, the Sun has a lower density, or mass per unit volume, than Earth. The Sun’s average density is only 1.409 g/cu cm (1.188 oz/cu in), which is a quarter of the average density of Earth.\n\nThe Sun produces an enormous amount of light. It generates 3.83 × 1026 watts of power in the form of light. In comparison, an incandescent lamp emits 60 to 100 watts of power. The temperature of the outer, visible part of the Sun is 5500°C (9900°F). \n\nFrom Earth the Sun looks small, because it is far away. Its average distance from Earth is 150 million km (93 million mi). Light from the Sun takes about eight minutes to reach Earth. This light is still strong enough when it reaches Earth, however, to damage human eyes when viewed directly. The Sun is much closer to Earth than any other star is. The Sun’s nearest stellar neighbor, Proxima Centauri (part of the triple star Alpha Centauri), is 4.3 light-years from our solar system, meaning light from Proxima Centauri takes 4.3 years to reach the Sun. The Sun is so much closer to Earth than all other stars are that the intense light of the Sun keeps us from seeing any other stars during the day.\n\nA  Importance to Earth \n\nEarth would no
681686
Na emits light at a primary wavelength of 589.0 nm (plus at a couple other wavelengths).  This light is a characteristic orangey-yellow, and is what makes street-lamps the colour they are, since many of them are sodium lamps.
835254
The sun emits energy at a rate of P = 4x10^26 W. The amount of power density that reaches the icy planey is then this\n\nPd = P/(4*pi*R^2)\n\nwhere R is the distance from the sun to the planet. This is the total flux of energy emitted by the sun spread over the surface area of a sphere of radius R. The albedo (A) of a planet indicates how much of the incident energy is reflected back into space. The absorbed power density is then\n\nPa = (1 - A)*Pd = (1 - A)*P/(4*pi*R^2).\n\nThe absorbed energy heats the planet and also leads to radiation. The radiated power follows the Stefan-Boltzmann law\n\nPr = e*s*T^4\n\nwhere e is the emissivity, s is Stefan's constant, and T is the temperature of the radiating body. Stefan's constant is s = 5.67x10^-8 W/(m^2*K^4), and for a blackbody, the emissivity is one.\n\nAt equilibrium, the absorbed power and the radiated power are equal\n\n(1 - A)*P/(4*pi*R^2) = s*T^4\n\nwhich can be solved for T, the temperature of the planet.\n\nThe temperature of the planet will impart kinetic energy to gas molecules in the air. The speed of the molecules will be distributed with an rms spedd os\n\nVrms = sqrt(3*k*T/m) = sqrt(3*R*T/M)\n\nwhere k is Boltzmann's constant, R is the universal gas constant, m is the mass of the molecule, and M is the molar mass.\n\nFor a planet the escape velocity for an object is given by\n\nVesc = sqrt(2*G*M/r)\n\nwhere G is the universal gravitation constant, M is the mass of the planet, and r is the planet's radius.\n\nIf the speed of the gas molecules is greater than the escape velocity of the planet, then that planet will not be able to retain that gas at the given temperature.
414227
You guys got a lot of it, but the sun is actually green. The atmosphere absorbs much of the light to make it more of a yellowish white light. Pollution and the ozone layer trap and absorb the green light that the sun produces. Then you see what you see. (were you looking at the sun??? :)
388047
The Sun does not "burn", like we think of logs in a fire or paper burning. The Sun glows because it is a very big ball of gas, and a process called nuclear fusion is taking place in its core. Nuclear fusion occurs when one proton smashes into another proton so hard that they stick together...and release some energy as well. This energy then heats up the other materials (other protons and electrons and such) nearby. This heating eventually grows out from the center (or core) of the star to the outside, finally leaving the surface and radiating out into space to be the heat and light we know stars emit. People, including scientists, sometimes say that the Sun "burns hydrogen" to make it glow. But that is just a figure of speech. Hydrogen really doesn't burn, it fuses, into helium. So no oxygen is required!
399301
In essence, the sun is a gargantuan nuclear fusion reactor. It uses hydrogen as its fuel, the fusion process creates helium, which is lighter than hydrogen. Witin the sun, hydrogen is 'falling' toward the core, as helium is rising to the surface, causing convection currents. This is what gives the sun its mottled appearance. Sunspots occasionally occur, these oddities are associated with geomagnetic storms which send tons of radiation hurtling into space as a solar flare, or a larger coronal mass ejection. When this radiation interacts with our magnetosphere here on earth, spectacular light shows ensue around the poles...the Aurorae. These bursts of electromagnetic energy also play havoc on radio reception. The sun is a complex engine of massive power and energy, but it's still in essence a fusion reactor.
1088371
As far as I know, all of them.  Emission spectra are caused by electrons absorbing energy and moving to a higher energy orbit or state (in the case of visible light it is a higher orbit) then when the electron goes back down to the lower state that it usually inhabits, it gives off a photon of an energy equal to the change in the energy level of the electron.  All elements can have excited electrons, and all electrons give off photons when they return to ground state, so all electrons give off emission spectra.\nIf you know of some element out there that doesn't I would be really interested to know what's going on with it.
61528
Our sun is a yellow star, so it has slightly yellow light, but it is still pretty close to white light.\n\nSunlight on earth is slightly yellower than it is in space because some of the blue light in sunlight gets scattered out by the presence of nitrogen in the air, making the sky appear blue. So \n\n(White light) - (Some Blue light) = (Yellow light)\n\nAs the sun sets, the sunlight travels through more air, and the nitrogen scatters out more blue light and the sun appears first orange, and then finally red.\n\nAs the sun starts to set:\n\n(White light) - (More Blue light) = (Orange light)\n\nand finally as the sun has almost set:\n\n(White light) - (Lots of Blue light) = (Red light)
985287
THe SUN IS NOT BURNING. IT IS MADE UP OF MILLION OF STARS SO IT DOES NOT NEED TO BURN.