New findings suggest hundreds of millions of planets may harbor life

New findings suggest hundreds of millions of planets may harbor life
New data suggests there could be millions of planets with gentle-enough orbits around their stars to sustain life
New data suggests there could be millions of planets with gentle-enough orbits around their stars to sustain life
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New data suggests there could be millions of planets with gentle-enough orbits around their stars to sustain life
New data suggests there could be millions of planets with gentle-enough orbits around their stars to sustain life

When Meatloaf sang “Two Out of Three Ain’t Bad” in 1977, we’re all but certain he was not doing the math on the potential of planets in the galaxy having the right conditions to harbor life. Because new findings suggest that two out of three are actually bad, unless you’re in search of uninhabitable baked planets with boiling oceans.

However, it’s in the remaining one third that now has scientists excited, as this fraction still accounts for hundreds of millions of planets that could be in a "just right" goldilocks orbit around a M (red) dwarf star that would enable it to retain liquid water and potentially support life.

“I think this result is really important for the next decade of exoplanet research, because eyes are shifting toward this population of stars,” said Sheila Sagear, a professor at the University of Florida. “These stars are excellent targets to look for small planets in an orbit where it’s conceivable that water might be liquid and therefore the planet might be habitable.”

There’s been much conjecture surrounding the ability of exoplanets to support life. Some scientists have suggested as many as 300 million planets could land in the habitable zone, and that Earth-like planets could be more prevalent than we’d previously thought. Yet there are conflicting factors, such as solar flares from the active M dwarf stars shooting life-zapping radiation onto a planet’s surface, as well as many unknown factors about atmospheric makeup that could make its promising gentle orbit a moot point.

For this new study, Sagear and researcher Sarah Ballard analyzed the orbit eccentricities of 163 M-dwarf exoplanets, using data from NASA’s Kepler space telescope captured between 2009 and 2019, and ESA’s Gaia telescope. Through the Kepler imaging, they were able to measure orbits by assessing how long the planets took to pass across the face of their star. New intel from Gaia provided the means to measure the distance to billions of stars across the galaxy.

“The distance is really the key piece of information we were missing before that allows us to do this analysis now,” Sagear said.

Orbit eccentricities relate to the shape of a planet’s path around their star. Most orbits aren’t circular, including Earth’s, but our planet has enough distance between it and the Sun that the shape of the journey doesn’t have the same kind of effect on weather.

In comparison, if a planet orbits closer to its star, an eccentric path causes drastic changes in gravitational forces, resulting in friction that heats the surface, a phenomenon known as tidal heating. As such, it renders these planets inhabitable for life as we know it.

“It’s only for these small stars that the zone of habitability is close enough for these tidal forces to be relevant,” said Ballard.

A third of the 2,600 planets identified by Kepler had gentle enough orbits to keep them in the habitable zone, opening the door to exploring them more closely for evidence of lifeforms.

While M dwarf stars, around 70% of known stars, are half the size of the Sun, or less, they’re also not as hot. So they have the "just right" potential to sustain life.

The researchers also found that M dwarf stars with multiple planets were more likely to have these more circular, gentle orbits, while single planets were subjected to more orbital extremes making their surfaces inhospitable.

“Since one-third of the planets in this small sample had gentle enough orbits to potentially host liquid water, that likely means that the Milky Way has hundreds of millions of promising targets to probe for signs of life outside our Solar System,” the researchers noted in their paper.

The study was published in the journal PNAS.

Source: University of Florida

I've always wondered how many of the supposed planets transiting the stars are actually just long lived sun spots on rotating stars. Like the sunspot cycle of our sun could these dwarf stars also have a repeating cycle which could be mistaken for planets with a longer orbit? When it comes to finding life, its a miracle that we even exist on this planet.
People generally don't realize how extreme the odds are that a single reproducing cell could come into existence. A single protiene molecule is unusual enough to form, even in ideal conditions. And the same conditions that permit it to form, also tend to destroy it. And you have to have a LOT of these molecules come together at once to even start the process.
So, those 300 million suggested planets for life to exist (which is probably wildly optimistic) are an EXTREMELY tiny fraction of the number of planets for the statistical possibility of life to form. Even if every single atom in the observable universe (i.e. the "Hubble Sphere") were a planet exactly like Earth, the statistics just don't allow for the possibility of life to form. That is why some atheist astronomers are going to the idea of an infinite number of universes. With infinities involved, everything becomes possible. And though there is no evidence of this, that seems to be where they are hanging their hat. Talk about blind faith.
BJ Bennett
Really? So they "may" be in temperature zone that sometimes allows for liquid water? Nothing said about how many are tidally locked (don't rotate and thus nly have a small band of temperate surface). How many have atmospheres? How many with atmospheres have too much whether to support life and how many are too stale to support life? How many have just the right amount of gravity, aren't affected by the giant space storms we see, have just the right concentrations of just the right elements in just the right quantities, and on and on and on. Beyond which, how many have been in homeostasis with all these perfect combinations for enough evolutionary eons to even have successful single cell organisms? We need to move beyond our Star Treck, Star Wars images of an explorable space full of new and exciting worlds. Every moment spent with our heads in space is a moment lost to the only real frontier: exploring new ways to care for what we have.
This article should stress an important fact: We know of only ONE planet that supports life right now. I hope I live long enough to learn what is discovered on the ocean bearing moons of the solar system's gas giants. If we find life there,the odds of life on planets outside the solar system would be almost certain.
Nelson Hyde Chick
And all these planets that can harbor life, it would only take a couple hundred years moving at the speed of light to get there.