Radio Astronomy: Observing the Invisible Universe

Even on the clearest, darkest night, one cannot see more than five percent of the light from the Milky Way, because of the blockage of light by dust; the 20th century brings radio astronomy, the study of radio waves that travel through the dust.

Learning how scientists infer temperatures and energy sources of different planets; the difference between their images in reflected sunlight and their appearance when one sees the radio energy they emit on their own.

When Karl Jansky is tasked to find natural radio sources that could interfere with commercial transatlantic radio communications, radio astronomy is born; the discovery of synchrotron radiation; understanding cosmic rays and magnetic fields.

After the birth of radio astronomy, a Dutch student tries to determine that if hydrogen exists in interstellar space, it would produce a specific spectral line at radio wavelengths; understanding of the universe changes forever.

Knowing why radio telescopes are so large; for example, the signal from a standard cell phone measured one kilometer away is five million billion times stronger than the radio signals received from a bright quasar; how these instruments are designed.

There is still more hydrogen today than any other element; the quantum physics of this simplest atomic structure; using the Doppler shift and models of differential rotation in the Milky Way, astronomers make myriad discoveries about the universe.