The Hot And Cold Past Of The Air Conditioner In the Northeast, the leaves have started changing colors, heralding the season of pumpkins, sweaters, and the smell of woodsmoke. But in some parts of the country, the heat hasn’t let up. In cities like Dallas, Phoenix, and Miami, temperatures were up in the high 80s and low 90s this week—and with climate change, the U.S. is only getting hotter. But humans have come up with an ingenious way to keep the heat at bay: air conditioning. Widely considered one of the greatest engineering achievements of the 20th century, the technology has transformed how and where people live—and it’s prevented countless deaths. But it comes at a cost, and if we’re going to keep up with a warming climate, we’re going to need some other tricks to stay cool. Remembering Frank Drake, Who Listened To The Cosmos Last week, astronomer and SETI pioneer Dr. Frank Drake died at the age of 92. Dr. Drake was a key figure in the search for extraterrestrial intelligence—from Project Ozma in 1960, to the founding of the SETI Institute. He collaborated on the ‘Golden Record’ that Earth sent to the stars on board the Voyager space probes. Drake also created a mathematical way of estimating the probability of discovering signs of intelligent life, a calculation that became known as the Drake Equation, and spent years advocating for the search for alien life. Drake appeared on Science Friday many times over the years. Here, in excerpts from conversations recorded in 2010 and 2016, he talks with Ira about the search for extraterrestrial intelligence, and his role with the Voyager Golden Record project. Our condolences to his family, friends, and colleagues. Transcripts for each segment will be available the week after the show airs on sciencefriday.com.     Subscribe to this podcast. Plus, to stay updated on all things science, sign up for Science Friday's newsletters.