Radio Astronomy: Observing the Invisible Universe

Series: Great Courses

4.8

(26)

Episodes

Rating

Year

2017

Language

English

Publisher

The Great Courses

About

Radio astronomy allows us to more accurately tell time right here on Earth, study terrestrial plate tectonics, and even get smartphone directions to that great new restaurant. Radio Astronomy: Observing the Invisible Universe takes you on a thrilling journey through the universe with stunning visuals and animations to explain the science of radio astronomy and its astounding discoveries.

Related Subjects

Episodes

1. Radio Astronomy and the Invisible Universe

30m

Even on the clearest, darkest night you cannot see more than five percent of the light from our home galaxy, the Milky Way, because of the blockage of light by dust. Fortunately, the 20th century brought us radio astronomy, the study of radio waves that travel through the dust, opening our "eyes" to a universe we had never imagined.

2. Thermal Radio Emission

30m

Take a tour of our neighboring planets via their radio emissions and learn how scientists infer their temperatures and energy sources. You'll be shocked by the difference between their images in reflected sunlight - the images we're familiar with - and their appearance when we "see" the radio energy they emit on their own.

3. The Birth of Radio Astronomy

30m

When young engineer Karl Jansky was tasked to find natural radio sources that could interfere with commercial transatlantic radio communications, radio astronomy was born. His work led to the discovery of synchrotron radiation. But it would be decades before scientists understood what these earliest radio astronomers had detected - cosmic rays and magnetic fields.

4. The Discovery of Interstellar Hydrogen

30m

Not long after the birth of radio astronomy, a Dutch student used what was then known about the physics of atoms to determine that if hydrogen existed in interstellar space, it would produce a specific spectral line at radio wavelengths. In 1951, the line was detected at 21 cm, exactly as predicted. At that moment, our understanding of the universe forever changed.

5. Radio Telescopes and How They Work

30m

Radio telescopes are so large because radio waves contain such a small amount of energy. 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. Learn how each of these fascinating instruments is designed to meet a specific scientific goal.

6. Mapping the Hydrogen Sky

30m

Before there were stars and planets, before there were galaxies, there was hydrogen - and we still have more hydrogen today than any other element. Understanding the quantum physics of this simplest atomic structure, and using the Doppler shift and models of differential rotation in the Milky Way, astronomers have made myriad astounding discoveries about the universe. It all starts with hydrogen.

7. Tour of the Green Bank Observatory

30m

The Green Bank Observatory is located within the 13,000-acre National Radio Quiet Zone straddling the border of Virginia and West Virginia. Come tour this fascinating facility where astronomers discovered radiation belts around Jupiter, the black hole at the center of our galaxy, and the first known interstellar organic molecule, and began the search for extra-terrestrial life.

8. Tour of the Green Bank Telescope

30m

At 17 million pounds, and with more than 2,000 surface panels that can be repositioned in real time, this telescope is one of the largest moveable, land-based objects ever built. The dish could contain two side-by-side football fields, but when its panels are brought into focus, the surface has errors no larger than the thickness of a business card. Welcome to this rare insider's view.

9. Hydrogen and the Structure of Galaxies

30m

Using the laws of physics and electromagnetic radiation, astronomers can "weigh" a galaxy by studying the distribution of its rotating hydrogen. But when they do this, it soon becomes clear something is very wrong: A huge proportion of the galaxy's mass has simply gone missing. Welcome to the topsy-turvy world of dark matter - which we now believe accounts for 90 percent of our own Milky Way.

10. Pulsars: Clocks in Space

30m

In the mid-1960s, astronomers discovered signals with predictable periodicity but no known source. In case these signals indicated extraterrestrial life, they were initially labeled LGM, Little Green Men. But research revealed the source of the pulsing radiation to be neutron stars.

Extended Details

SeriesGreat Courses

Closed CaptionsNo

Artists

Felix J. LockmanWriter

Felix J. LockmanActor