This week, we chat about cement’s shrinking carbon footprint, commuting hazards for ancient Egyptian artisans, and a new bipartisan group opposed to government-funded animal research in the United States with Online News Editor David Grimm. Plus, Science’s Alexa Billow talks to news writer Sam Kean about the kinds of data that can only be gathered at night as part of the special issue on circadian biology.  Listen to previous podcasts.  [Image: roomauction/iStockphoto; Music: Jeffrey Cook]

This week we chat about why it’s hard to get a taxi to nowhere, why bones came onto the scene some 550 million years ago, and how targeting bacteria’s predilection for iron might make better vaccines, with Online News Editor Catherine Matacic. Plus, Science’s Alexa Billow talks with news writer Elizabeth Pennisi about the way hybrids muck up the concept of species and turn the evolutionary tree into a tangled web.   Listen to previous podcasts   [Image:  Raul González Alegría; Music: Jeffrey Cook]

If light can’t escape from black holes, how can we observe them at all? Find out from astrophysicist Janna Levin, co-host Matt Kirshen, and Shep Doeleman, the MIT astrophysicist leading the Event Horizon Telescope project to study black hole Sgr A* at the center of our galaxy.

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