1. Olber's Paradox
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This quick video describes Olber's paradox, how it challenges an infinite universe and how it is consistent with our current understanding of the origin of the universe.
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2. The Big Bang
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Coming Soon
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3. Stellar Spectroscopy
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How can we determine properties of stars? By studying their spectra, we can learn a lot. This video covers, composition, temperature, density and motion
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4a. Determining Distance - Stellar parallax
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Stellar parallax is a method, using basic trigonometry, to determine the distance of stars within our galaxy. Using concrete and visual examples, I explain the methodology, why distance are defined in parsecs, and the limitation of the technique.
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4b. Determining Distance - Stellar parallax
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Stellar parallax is not a suitable method for distance beyond 100pc. Henrietta Leavitts work led to a better way of deterring steel;ar distance, through the use of variable stars called Cepheid variables
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5. Stellar Magnitude
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Stellar brightness is often quoted in terms of magnitude, whether apparent or absolute. This video explains the origins of these terms, the mathematics behind them and the limitations of using brightness as a means to discussing stellar properties.
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6. Stellar Temperature
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The colour of a glowing object is related to temperature but despite this, astronomers do not use colour directly to determine a star's surface temperature. After reviewing blackbody radiation, this video discusses why this is and also reviews the two ways astronomers determine a star's temperature.
I refer to the paper by René Heller and Jan-Vincent Harre. You can find their paper here - https://arxiv.org/abs/2101.06254 |
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7. HR Diagram.
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In this video I review the HR (or Hertzsprung Russell) Diagram. Quickly reviewing the concepts of brightness and colour of a star, I show you how we can classify stars and how that leads to better understanding of the nature of stars.
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