Dust can mask star formation in the present Universe, too.
Many dominant emission lines exist in the far infrared range of the electromagnetic spectrum for us to use as a probe through this dusty veil. How the elements propagate in the Universe is very important. We know where the elements are formed. To answer these questions, astronomers must not only be able to see the matter, but also how it is moving. Lines observed in the far infrared can tell us such things as the density, pressure, velocity, and temperature.