Earth-like biospheres on other planets may be rare

[HAL9000]

The article makes an assumption that photosynthesis will be similar on other palents and tries to work out if the nearest star provides enough energy

By calculating the amount of photosynthetically active radiation (PAR) that a planet receives from its star, the team discovered that stars around half the temperature of our Sun cannot sustain Earth-like biospheres because they do not provide enough energy in the correct wavelength range. Oxygenic photosynthesis would still be possible, but such planets could not sustain a rich biosphere.

Planets around even cooler stars known as red dwarfs, which smoulder at roughly a third of our Sun’s temperature, could not receive enough energy to even activate photosynthesis. Stars that are hotter than our Sun are much brighter, and emit up to ten times more radiation in the necessary range for effective photosynthesis than red dwarfs, however generally do not live long enough for complex life to evolve.

“Since red dwarfs are by far the most common type of star in our galaxy, this result indicates that Earth-like conditions on other planets may be much less common than we might hope,” comments Prof. Giovanni Covone of the University of Naples, lead author of the study.

Earth-like biospheres on other planets may be rare

A new analysis of known exoplanets has revealed that Earth-like conditions on potentially habitable planets may be much rarer than previously thought. The work focus...

ras.ac.uk

There are lot of red dwarf stars in the milky way

red dwarfs account for 70 to 80 percent of our galaxy’s stellar content

(grabbed the quote from this link, Why does the universe make so many tiny stars?, but I didn't read the article)

 

[2hats]

Though there are probably a billion, quite likely a few billion, Sun like (G-class) stars in the Milky Way. Besides which, as pointed out in the paper, there are evolutionary options for biologies that could photosynthesise down into near infra-red on planets around cooler stars (is suggested for future study).

 

[littlebabyjesus]

I still hold out hope for Europa. Sod photosynthesis. Planets/moons can provide their own sources of energy. After all, Earth does via hydrothermal vents.

There will be missions to Europa, Enceladus and Titan, hopefully in the next 10 to 15 years, to look for life. Still haven't given up hope of evidence of life on Mars, at least past life. But that may have the same origin of life as life on Earth, arrived via meteorite from Earth to Mars or from Mars to Earth. Life on Europa would be of an independent origin from Earth.

If we find life here in the solar system, even if it's only prokaryotic life, that means life is ubiquitous in the universe. For me, that's the exciting thing to discover. Most life is probably single-cell. It took 3 billion years, nearly, for multicellular life to evolve on Earth. But if you have billions of cases of simple life starting up all over the place, as finding any kind of life anywhere on Europa, etc, would demonstrate is likely to be the case, who knows what things it could eventually discover through evolution? May be something different from eukaryotes, but producing amazing things as well.

Whatever, the real search for life is right here in the solar system, imo. Now how do we get to peep through those kilometres of ice that surround Europa?

 

[NoXion]

Yeah, I'm finding the base assumption of the article to be unwarranted. Photosynthetic processes which evolved around a Sun-like star are insufficient to support life around non Sun-like stars where they didn't evolve, go figure.

There are a great many more red dwarfs than yellow stars like our Sun. Even if the biochemical pathways that allow for photosynthetic processes around red dwarf stars are harder for natural selection to achieve, the sheer number of red dwarfs in the Milky Way could still mean that there is more plant life around red dwarfs than around Sun-like stars.

 

[Crispy]

Now how do we get to peep through those kilometres of ice that surround Europa?

By flying through the plumes of water that escape through cryovolcanism and doing mass spectroscopy on it.

Europa Clipper - Wikipedia

en.wikipedia.org

No results till after 2030 though