Neutrino astronomy distinguishes itself from common astronomy to the extent that it employs in place of visible light, which is used in optical astronomy for observation and analysis, a different kind of radiation from the universe, namely neutrinos. Our present knowledge in astronomy is almost exclusively due to observations that are based on optical and other kinds of observations that use as information carrier photons, i.e., electromagnetic waves or radiation, such as light, radio waves, infrared, ultraviolet, gamma or X-rays.

These radiations are all of the same kind and distinguish themselves only in the energy content of the photons (or quanta). They are signatures of electromagnetic interactions that are frequently secondary or even tertiary processes and the consequence of other, more fundamental processes that are going on in the universe. The latter are often not directly observable because they are governed by one of the three other fundamental interactions (or forces) whose signatures are more elusive.

(The four fundamental forces or interactions are: The strong or nuclear force [1], the electromagnetic force [10^-2], the weak force [10^-15] and the gravitational force [10^-40]. The figures in brackets are a measure of their relative strength.)

The reason why the step from optical or more generally from electromagnetic astronomy to neutrino astronomy is so significant is that neutrinos are of a fundamentally different nature. They are not subject to the laws of electromagnetic interactions but to those that govern weak interactions, i.e., they are coupled to another force. With their help many of the processes that occur throughout the universe that have only been accessible indirectly or not at all will become directly observable.

The enormous penetrating power of neutrinos may reveal the presence of astrophysical objects that are hidden behind dense clouds of dust that remain unobservable by electromagnetic radiation. Even viewing the interior of stars is no longer intangible. Neutrino astronomy harbors a high discovery potential for hitherto unknown processes and systems and will undoubtedly enrich our inventory of the universe. Neutrino astronomy and neutrino astrophysics will open a new world for the scientists, a New Window into the Universe.