The Faint Young Sun Paradox!04:33

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Published on January 26, 2017

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Credits (and handles):
Script Writer: Emily Elert (@eelert)
Script Editor: Rachel Becker (@RA_Becks)
Video Illustrator: Ever Salazar (@eversalazar)
Video Director: Emily Elert (@eelert)
Video Narrator: Emily Elert (@eelert)
With Contributions From: Henry Reich, Alex Reich, Kate Yoshida, Omkar Bhagat, Peter Reich, David Goldenberg
Music by: Nathaniel Schroeder:


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If you liked this week’s video, we think you might also like this:
Fantastic Aurora: Inside the Sun to Earth’s Poles

FYI: We try to leave jargon out of our videos, but if you want to learn more about this topic, here are some handy keywords to get your googling started:

Abiogenesis – the process of life arising from non-living matter, such as simple organic compounds.

Amino Acids – a class of organic compounds. Twenty of the roughly 500 known amino acids appear in the genetic code, and, when strung together into long chains, form the basic building blocks of proteins.

Faint Young Sun Paradox – describes the apparent contradiction between evidence for a warm ancient Earth, and stellar models, which predict that the young Sun was 25% dimmer than today’s Sun. First described by Carl Sagan and George Mullen in 1972.

The Miller–Urey experiment – a landmark experiment in the 1950s in which scientists demonstrated that amino acids could form spontaneously from inorganic gases present in Earth’s early atmosphere

Snowball Earth – a climatic state of Earth in which the entire surface becomes frozen over.

Molecules featured in this video:
– Carbon dioxide (CO2)
– Methane (CH4)
– Nitrous oxide (N20)
– Hydrogen cyanide (HCN)
– Amino acids (especifically threonine, valine, cysteine and methionine)
– Adenine (C5H5N5)
– Glycine (C2H5NO2)



Airapetian, V. S., Glocer, A., Gronoff, G., Hébrard, E., & Danchi, W. (2016). Prebiotic chemistry and atmospheric warming of early Earth by an active young Sun. Nature Geoscience Nature Geosci, 9(6), 452-455. doi:10.1038/ngeo2719

Earth’s changeable atmosphere. (2016). Nature Geoscience Nature Geosci, 9(6), 409-409. doi:10.1038/ngeo2735

Feulner, G. (2012). The faint young Sun problem. Rev. Geophys. Reviews of Geophysics, 50(2). doi:10.1029/2011rg000375

Leconte, J., Forget, F., Charnay, B., Wordsworth, R., & Pottier, A. (2013). Increased insolation threshold for runaway greenhouse processes on Earth-like planets. Nature, 504(7479), 268-271. doi:10.1038/nature12827

Marchi, S., Black, B., Elkins-Tanton, L., & Bottke, W. (2016). Massive impact-induced release of carbon and sulfur gases in the early Earth’s atmosphere. Earth and Planetary Science Letters, 449, 96-104. doi:10.1016/j.epsl.2016.05.032

Sagan, C., & Mullen, G. (1972). Earth and Mars: Evolution of Atmospheres and Surface Temperatures. Science, 177(4043), 52-56. doi:10.1126/science.177.4043.52

Wolf, E. T., & Toon, O. B. (2014). Delayed onset of runaway and moist greenhouse climates for Earth. Geophys. Res. Lett. Geophysical Research Letters, 41(1), 167-172. doi:10.1002/2013gl058376

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