New study darkens hope for Earth-like planets
Most planets can't host plant life.
A new study examines if exoplanets get enough stellar radiation to support photosynthesis. Many planets within the habitable zones of stars do not receive enough energy to support plant life. Earth-like planets are probably very rare.
Since 1961, astrobiologists and others interested in finding extraterrestrial life have used the Drake equation to speculate on the possible number of technologically advanced alien civilizations in the Milky Way. By multiplying factors like the number of new stars in the galaxy per year, how many planets those stars have, the number of planets suited to life, and how long intelligent civilizations emit radio waves, one can get an estimate of how many other intelligent species are out there right now.
The problem is that the equation is almost entirely speculative because many of the factors have unknown values. But every once in a while, new information helps to narrow down the range of reasonable values to plug in.
Bad news for E.T. enthusiasts: a new study published in Monthly Notices of the Royal Astronomical Society offers a further narrowing of those values. By examining the conditions needed for photosynthesis, the authors propose that biospheres suitable for life might be rarer than we thought.
Let there be (a little more) light: The study’s authors looked at what conditions are needed for the biochemical process that makes most life on Earth possible, oxygenic photosynthesis. By combining carbon dioxide with water and light, species capable of oxygenic photosynthesis produce sugar and oxygen. The latter is released as a waste product.
The authors, like many before them, conjecture that photosynthesis is common throughout the galaxy on account of how much stellar radiation there is to collect, the (comparative) simplicity of the process, and the abundance of the other input elements.
As it turns out, good real estate is hard to come by in the Milky Way.
Stars that burn at half the heat of the sun do not provide enough energy for a rich biosphere to ever arise. Red dwarf stars, which are small, numerous, and burn at about a third of the sun’s temperature, were even worse. They couldn’t provide the energy needed for much photosynthesis at all.
Full article
https://bigthink.com/hard-science/exoplanet-photosynthesis/
Most planets can't host plant life.
A new study examines if exoplanets get enough stellar radiation to support photosynthesis. Many planets within the habitable zones of stars do not receive enough energy to support plant life. Earth-like planets are probably very rare.
Since 1961, astrobiologists and others interested in finding extraterrestrial life have used the Drake equation to speculate on the possible number of technologically advanced alien civilizations in the Milky Way. By multiplying factors like the number of new stars in the galaxy per year, how many planets those stars have, the number of planets suited to life, and how long intelligent civilizations emit radio waves, one can get an estimate of how many other intelligent species are out there right now.
The problem is that the equation is almost entirely speculative because many of the factors have unknown values. But every once in a while, new information helps to narrow down the range of reasonable values to plug in.
Bad news for E.T. enthusiasts: a new study published in Monthly Notices of the Royal Astronomical Society offers a further narrowing of those values. By examining the conditions needed for photosynthesis, the authors propose that biospheres suitable for life might be rarer than we thought.
Let there be (a little more) light: The study’s authors looked at what conditions are needed for the biochemical process that makes most life on Earth possible, oxygenic photosynthesis. By combining carbon dioxide with water and light, species capable of oxygenic photosynthesis produce sugar and oxygen. The latter is released as a waste product.
The authors, like many before them, conjecture that photosynthesis is common throughout the galaxy on account of how much stellar radiation there is to collect, the (comparative) simplicity of the process, and the abundance of the other input elements.
As it turns out, good real estate is hard to come by in the Milky Way.
Stars that burn at half the heat of the sun do not provide enough energy for a rich biosphere to ever arise. Red dwarf stars, which are small, numerous, and burn at about a third of the sun’s temperature, were even worse. They couldn’t provide the energy needed for much photosynthesis at all.
Full article
https://bigthink.com/hard-science/exoplanet-photosynthesis/
