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Here you can watch video lectures on astronomy topics. Watch one of 29 individual playlists, or use the Wikimap to find similar topics.

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Articles related to: Steps of the Scientific Method  Read article

1. Chinese Astronomy  Read article

Chinese astronomers were predicting eclipses over three thousand years ago. There is ample evidence that Chinese astronomy flourished before the great age of Greek philosophy and science. Chinese astronomers left detailed observations of the recurrence of Halley’s Comet, of fireballs in the sky, a...

2. The Scientific Method  Read article

The scientific method is a way of gaining knowledge about the world we live in. Science starts with curiosity about nature, observing the world, but there is a method to science, a way that distinguishes it from other modes of thought. Science is based upon evidence, upon observations. Scientists...

3. Ancient Astronomy  Read article

For tens of thousands of years humans have used the sky, the daytime sky and the night sky, as a map, a clock, and a calendar.  The first astronomy thus is directly tied into human culture, into the needs for hunter gatherers to move around, follow the migrating herds, garnish food sources, and prot...

4. Cosmological Parameters  Read article

The big bang model is described by a small number of cosmological parameters. Astronomers talk about a world model, but in fact they’re talking about a description of the entire universe. If these parameters are measured, the entire history of the universe, past, present, and future, can be descri...

5. Dark Matter in Clusters  Read article

The first good evidence for dark matter in astronomy came from observations of the Coma cluster by Fritz Zwicky in the 1930s. This Caltech astronomer measured radial velocities from many galaxies in the Coma cluster and showed that the velocity dispersion was far too high to be accounted for by vis...

6. Natural Selection  Read article

By the middle of the eighteenth century, scientists began to suspect that fossils represented the extinct ancestors of living species. The French naturalist Lamarck suggested that these species had failed to adapt to their environment and so had not endured. The question was why and how? What was...

7. Evidence for Cosmic Acceleration  Read article

The primary evidence that the universe is currently accelerating comes from distant supernovae. The observation is based on the fact that a standard cosmology filled with only radiation and matter, most of which is dark matter, predicts the brightness of distant objects. Supernovae at redshifts of...

8. Evidence of Life on Mars  Read article

How good is the evidence for ancient life on Mars based on the Allen Hills Meteorite? The evidence comes in two forms, first evidence for organic material. There are indeed hydrocarbons within the meteorite, but they need not represent decayed organisms. There are also magnetite and iron sulfite ...

9. Earth's Atmosphere  Read article

Astronomers not only worry about reddening and extinction in the interstellar medium, but they also must worry about it in the Earth’s atmosphere. Just as the Sun becomes redder and dimmer when it’s close to the horizon so does any star in the night sky. This effect is not obvious to the eye, but ...

10. Evidence of Formation  Read article

Interplanetary debris gives astronomers evidence of the formation process of the solar system. Icy material like cometary debris has never been significantly heated in the 4.6 billion year history of the solar system. Interplanetary dust grains are probably cometary debris, and they filter though ...