The topic of extra-solar planets that may harbor life has been a lively one lately. Earlier this year we wrote Ken Ham Says There’s No Extraterrestrial Life. But that was based on scripture and speculation. Then some astronomical evidence was found.
The first of our recent posts about this was a month ago: Newly Discovered Habitable Extra-Solar Planet, followed by ICR’s reaction: Newfound Extra-Solar Planet: No Chance for Life, and then Discovery Institute: Extraterrestrial Life Is OK.
Now we have some more astronomical evidence to report. At the website of the University of California, Berkeley we read Study says solar systems like ours may be common. Here are some excerpts, with bold added by us:
Nearly one in four stars like the sun could have Earth-size planets, according to a University of California, Berkeley, study of nearby solar-mass stars.
How’s that for a good start? Let’s read on:
UC Berkeley astronomers Andrew Howard and Geoffrey Marcy chose 166 [type] G and [type] K stars within 80 light years of Earth and observed them with the powerful Keck telescope for five years in order to determine the number, mass and orbital distance of any of the stars’ planets. The sun is the best known of the G stars, which are yellow, while K-type dwarfs are slightly smaller, orange-red stars.
They looked at 166 of those stars within only 80 light years of us? Astronomically speaking, that’s virtually right next door. We’ve seen estimates that 1 in 13 stars in our “neighborhood” (a “tiny” region of roughly 3 million stars) is type G, and 1 in 8 is type K. This galaxy is estimated to be about 100,000 light years in diameter, containing at least 200 billion stars, so the number of such stars in just this galaxy is enormous.
What did Howard and Marcy find? We continue:
The researchers found increasing numbers of smaller planets, down to the smallest size detectable today – planets called super-Earths, about three times the mass of Earth.
“Of about 100 typical sun-like stars, one or two have planets the size of Jupiter, roughly six have a planet the size of Neptune, and about 12 have super-Earths between three and 10 Earth masses,” said Howard, a research astronomer in UC Berkeley’s Department of Astronomy and at the Space Sciences Laboratory. “If we extrapolate down to Earth-size planets – between one-half and two times the mass of Earth – we predict that you’d find about 23 for every 100 stars.”
The creationists aren’t going to like this. We look forward to posting about their reactions. Here’s more from UC Berkeley:
“This is the first estimate based on actual measurements of the fraction of stars that have Earth-size planets,” said Marcy, UC Berkeley professor of astronomy. Previous studies have estimated the proportion of Jupiter and Saturn-size exoplanets, but never down to Neptunes and super-Earths, enabling an extrapolation to Earth-size planets.
Okay, it’s just an “extrapolation.” Nevertheless, things are looking good out there for the possibility of finding planets like our own. Moving along:
“What this means,” Howard added, “is that, as NASA develops new techniques over the next decade to find truly Earth-size planets, it won’t have to look too far.”
Extrapolating further, this means that life is likely to be everywhere! But there’s also this:
“Just where we see the most planets, models predict we would find no cacti at all,” Marcy said. “These results will transform astronomers’ views of how planets form.”
No “cacti”? Well, whatever. There’s a lot more at the UC Berkeley article. And here’s a link to the paper Howard and Marcy just had published in Science: The Occurrence and Mass Distribution of Close-in Super-Earths, Neptunes, and Jupiters.
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