	Basic Level
				When the indicator is fully coloured, there is material specifically developed for that level.
	Intermediate Level
				When the indicator is half-coloured, the material from another level may be appropriated for this level. Give it a look!
	Advanced Level
				When the indicator has no colour at all, the Science Case is not recomended for that level.
	Super Hero Level

Astronomers call Interstellar Medium (ISM) to the matter and the radiation in between stars, within the same galaxy. This matter presents extremely low densities, in comparison to Earth's densities, and it can be found as ionic, atomic and molecular matter. In a nutshell, 99% of the ISM is in form of gas, mostlyhydrogen (75%) and helium (25%), while the remaining 1%, is dust, made of grains of carbon, silica and so-called "dirty ice". The study of the interstellar medium is a fascinating topic, which offers the possibility to understand how dead stars (in the form of supernova) may impact with their environment and trigger star formation.