The Sun emits a plurality of electromagnetic waves, to far ultraviolet (FUV) such as gamma rays (higher frequencies) to radio waves (lower frequencies), through X-rays, ultraviolet rays, visible light, infrared radiation, microwaves. These electromagnetic waves, whose vector is the photon, move at speed of ≈300000 km/s. With our eyes, we see only the wavelengths in the visible range between 400 and 800 nm, but when it comes to shorter or longer wavelengths, we need to use specialized devices. Specialized instruments are usually ground or space telescopes equipped observing light in different wavelengths.
The sun sends us all colors of light as it is filled with all of the atoms present on Earth, each depending on the temperature, generates light in a certain wavelength. In addition to many different atoms (helium, hydrogen, carbon, oxygen, iron,...), the Sun also contains different types of ions of each atom of different electric charges. Each ion may also emit light at specific wavelengths when it reaches a particular temperature.
Each observed wavelength, therefore reveals information on the different elements (atoms or ions) of the surface and atmosphere of the Sun. By examining images of the Sun in a selected range of wavelengths, scientists can monitor particles and temperatures present in the Sun's atmosphere.
This image of the Sun was built based on telescope data SDO (Solar Dynamics Observatory), NASA. It shows a composition of the different aspects of the surface or of the sun's atmosphere, in 10 different wavelengths selected by the scientific and invisible to the naked eye. These lights are converted into visible colors so that humans can see them. The observed object, here the Sun, so appears in a great "patchwork" of colors. Since the 1900s, scientists list the wavelengths absorbed or emitted by atoms and ions and these associations between elements, wavelengths, temperatures and colors, are well documented.
The telescopes make use of this valuable information wavelength by embarking instruments such as spectrometers who observe several wavelengths simultaneously and measure the quantity of present elements to each wavelength.
SDO scientists identified 10 specific wavelengths to observe the atmosphere and the movement of atoms in the solar layers.
10 wavelengths (in angstroms) selected:
An angstrom (symbol Å) = 0.1 nm, or 10-10 meter or 1 tenth of a billionth of a meter.
1) 1700 Å C7 and D4 (pink brown), light 4,500 Kelvin, emitted by the sun's surface, photosphere and chromosphere.
2) 4500 Å in A4, D7 and E4 (yellow) light to about 6,000 Kelvin, emitted from the photosphere.
3) E3 1600 Å and C6 (yellow green), the light emitted by the carbon 4, to about 10,000 Kelvin, in an area between the upper photosphere and the transition region, a region between the chromosphere and corona.
4) 304 Å D3, B6, E7 and F4 (red), the light emitted from helium 2, to about 50,000 Kelvin, in the transition region and the chromosphere.
5) 171 Å in D2, C4, A5 and F6 (yellow brown), light emitted by the iron 9, to about 600,000 Kelvin, in the atmosphere or corona when it is calm.
6) 193 Å B2, B7, F5 (shiny brown), light emitted by iron 12, to about 1 million Kelvin and iron 24, to about 20,000,000 Kelvin, in slightly warmer areas of the crown and the much hotter material solar flares.
7) 211 Å A6, B3 and F2 (purple), the light emitted by iron 14, to about 2,000,000 Kelvin, in warmer regions and magnetically active crown.
8) 335 Å C1, B5, C8, F3, F7 (blue), the light emitted by iron 16, to about 2,500,000 Kelvin in the hotter regions of the magnetically active corona.
9) 94 Å C3 and D5 (dark green), light emitted by iron 18, to about 6,000,000 Kelvin, in very hot regions of the corona during a solar flare.
10) 131 Å E6 (blue green), the light emitted by the iron 20 and the iron 23 over 10 million Kelvin by the hottest elements solar ejections.
Image: this composition exhibits various aspects of the surface or the atmosphere of the Sun into 10 different wavelengths, invisible to the naked eye. These special lights sun is converted and colorful by the telescope SDO (Solar Dynamics Observatory) so that humans can see them. The observed object here the Sun appears in a beautiful "rainbow sky" colors representing the light of the Sun. More the temperature is higher, more the dominant color moves towards microwaves to gamma waves. The yellow light has a wavelength of ≈580 nm, it is typically from about atoms, heated to about 5700 ° C, which is the case of the surface of the Sun. Extreme deep ultraviolet lights such as gamma waves have a wavelength of ≈9 nm, it is usually colorized green in the SDO images, it usually comes from the atoms heated to about 6,300,000 ° C which is the case of solar eruptions which can reach temperatures as high. Credit: NASA / SDO / Goddard Space Flight Center