How Common Are Habitable Exoplanets? | Exoplanet Radio ep 24 

I need more and longer episodes

To really know if there's worlds around sun like stars these telescopes will have to sit and wait for the same amount of time 365 days +/- and 225 +/- days for K type stars. And these quick find are all red dwarf planets that take just days to transit

In order to see exoplanets as disks, per the Rayleigh criterion, you'll need a telescope with an aperture of about 20 kilometers.

If you survey the scientific literature, the answer is only a few advanced civilizations per galaxy, and possibly only one. So What changed? We now have 13 Habitable Zones instead of just water, all of which must overlap on a single planet. *Known Current Habitable zones as of 2019* - Water habitable zone - Ultraviolet/Radiation habitable zone - Photosynthetic habitable zone - Ozone habitable zone - Planetary rotation rate habitable zone - Planetary obliquity habitable zone - Tidal habitable zone - Astrosphere habitable zone - Electric wind habitable zone - Milankovich cycle zone - Stellar magnetic wind zone - Carbon dioxide zone - Carbon monoxide zone For host stars with an effective temperature more than 7,100 K (7,100 °C above absolute zero) or less than 4,600 K, even for just microbes, a team of four Chinese astronomers showed that the liquid water and ultraviolet habitable zones will not overlap. This may seem like a fairly wide effective temperature range, but it is narrow enough to eliminate all but 3 percent of the Milky Way Galaxy’s stars. Japanese astronomers Midori Oishi and Hideyuki Kamaya established that the zone of overlap is even narrower including the metallicity requirements of the Host star, this leaves less than 1 percent of our galaxy stars as candidates for bacterial life. Advanced life has even more stringent requirements. Scientific Articles: - Jianpo Guo et al., “Probability Distribution of Terrestrial Planets in Habitable Zones Around Host Stars,” Astrophysics and Space Science 323 (October 2009): 367-73 - Rory Barnes et al., "Tidal Limits to Planetary Habitability," Astrophysical Journal Letters 700 (July 20, 2009): L30-L33 - David S. Smith and John M. Scalo, “Habitable Zones Exposed: Astrosphere Collapse Frequency as a Function of Stellar Mass,” Astrobiology 9 (September 2009): 673-81 - Jun Yang et al., “Strong Dependence of the Inner Edge of the Habitable Zone on Planetary Rotation Rate,” Astrophysical Journal Letters 787, no. 1 (May 20, 2014): id. L2, doi:10.1088/2041-8205/787/1/L2. - Yutong Shan and Gongjie Li, “Obliquity Variations of Habitable Zone Planets Kepler-62f and Kepler-186f,” Astronomical Journal 155, no. 6 (May 17, 2018): doi:10.3847/1538-3881/aabfd1; Gregory S. Jenkins, “Global Climate Model High-Obliquity Solutions to the Ancient Climate Puzzles of the Faint-Young Sun Paradox and Low-Altitude Proterozoic Glaciation,” Journal of Geophysical Research: Atmospheres 105, no. D6 (March 27, 2000): 7357-70, doi:10.1029/1999JD901125. - Midori Oishi and Hideyuki Kamaya, “A Simple Evolutionary Model of the UV Habitable Zone and the Possibility of Persistent Life Existence: The Effects of Mass and Metallicity,” Astrophysical Journal 833 (December 2016): id. 293, doi:10.3847/1538-4357/833/2/293 - Glyn Collinson et al., “The Electric Wind of Venus: A Global and Persistent ‘Polar Wind’-Like Ambipolar Electric Field Sufficient for the Direct Escape of Heavy Ionospheric Ions: Venus Has Potential,” Geophysical Research Letters (June 2016): doi:10.1002/2016GL068327 - Glyn Collinson et al., “Electric Mars: The First Direct Measurement of an Upper Limit for the Martian ‘Polar Wind’ Electric Potential,” Geophysical Research Letters 42 (November 2015): 9128-34, doi:10.1002/2015GL065084 - Russell Deitrick et al., “Exo-Milankovitch Cycles. I. Orbits and Rotation States,” Astronomical Journal 155, no. 2 (January 16, 2018): id. 60, doi:10.3847/1538-3881/aaa301; Russell Deitrick et al., “Exo-Milankovitch Cycles. II. Climates of G-Dwarf Planets in Dynamically Hot Systems,” Astronomical Journal 155, no. 6 (June 4, 2018): id. 266, doi:10.3847/1538-3881/aac214; - adsabs.harvard.edu/cgi-bin/nph-ref_query?bibcode=2003ARA%26A..41..429K&refs=CITATIONS&db_key=AST - Hans O. Pörtner, Martina Langenbuch, and Anke Reipschläger, “Biological Impact of Elevated Ocean CO2Concentrations: Lessons from Animal Physiology and Earth History,” Journal of Oceanography 60, no. 4 (August 2004): 705-18, doi:10.1007/s10872-004-5763-0.