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Can a probe be sent out to shine a white laser through the atmosphere of a planet to measure a rainbow spectrum to determine composition, temperature, density etc.?

Water drops refracts about at a 40 degree angle bla bla, but other elements may refract different from water. Using a telescope can this angle be created between the optical telescope, planets, light source to get a visual spectral graph of a planet's atmospheric composition or parts there of?

enter image description here https://www.gizmodo.com.au/2012/06/wow-its-a-double-rainbow-from-space/

https://earthscience.stackexchange.com/questions/16308/rainbow-dynamics

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    $\begingroup$ Lasers are monochromatic: they produce light of a single wavelength. White lasers don't exist. $\endgroup$ – Hobbes Feb 21 at 18:29
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    $\begingroup$ No. That creates a beam that may look sort of white, but its spectrum still consists of 3 narrow lines. $\endgroup$ – Hobbes Feb 21 at 19:52
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    $\begingroup$ @Hobbes What about this? $\endgroup$ – called2voyage Feb 21 at 20:20
  • $\begingroup$ @Muze If you want more constant wavelengths than the Sun, you can't get white light. To get the visible white light, you need all wavelengths between about 400 to 800 nm. $\endgroup$ – Uwe Feb 21 at 20:49
  • $\begingroup$ @Muze To be clear, I was not endorsing a particular approach, just presenting a study summary which seemed to state a type of "white laser" developed could be used for spectroscopy. I'm interested in further context here--I'm not armed with information on the topic. $\endgroup$ – called2voyage Feb 21 at 21:02
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You don't need a laser to do this. The technique you describe is known as spectroscopy, and it can use any light source, including light from the planet's star. This is a common technique for studying Earth's atmosphere from space, and to study stars and planets from Earth.

This even works on planets in other solar systems. In a few years, an ESA mission will be launched to do spectroscopy on lots of exoplanets.

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    $\begingroup$ It should be noted that the way of discriminating different substances in spectroscopy is not their different refraction indices, but their different electronic energy levels. Refraction index is a pretty crude way to characterize a substance. $\endgroup$ – WaterMolecule Feb 21 at 22:13

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