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Episode 168 - Common (and False) Fine-Tuned Universe Beliefs, Discussed

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Recap: An exploration into four groups of fine-tuning arguments used by some to say that we are special: Solar outbursts, habitable zone, lunar origin and effects, and giant planets and impacts on Earth.

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Episode Summary

Claim: The claims in this episode come not from a religious background, which is the most common source of any claims dealing with an apparent fine-tuning of the universe, galaxy, solar system, or planet, the idea commonly being phrased along the lines of, if any of those things were slightly different we couldn't exist, therefore GodDidIt. In this episode, that's the claim, except for the "therefore GodDidIt." Replace "God" with "Aliens." I've heard these particular arguments before, sometimes even from people who don't have an agenda and just don't know, so I thought they'd make a good topic for the podcast.

There are four total, and instead of playing four clips, I'm going to play them all at once here, at the beginning, because that's how it's presented. The speaker is Whitley Strieber, a UFOlogist and fiction and, what he would claim, non-fiction writer. This is about 2 minutes 40 seconds long. [Clip from Whitley Streiber's 'Dreamland' from November 3, 2017, starting at 18:07]:

"What you see is this: The sun is a type of star known as a 'yellow dwarf.' Most yellow dwarfs have sterile planetary systems because they explode out ferocious waves of gamma rays every few hundred thousand years. We know this because we see them doing it in-[stutters]-in the galaxy. Now, ours does not! We know it doesn't because we wouldn't be here if it did. It is strikingly benign compared to most of its sisters or brothers, depending on how you look at it. Again, Earth is just in the exactly ss— exact center of the narrow 55— 50,000-mile deep habitable zone around this star. Third, the moon, which emerged out of a huge impact — you know what the crater on Earth— the Earth— was left behind on Earth that is, uh, by the moon? It's called the 'Pacific Ocean.' That was a big impact. Without the moon to slow the rotational winds of Earth, by— because it's at the perfect distance and is the perfect size, we would not be here, there would be nothing on the Earth more than lichens and things because the winds naturally generated by the rotation of the planet would be too strong. The moon acts as a kind of break. If the gas giants out beyond uh Mars weren't here, neither would we because we would've long since been destroyed by asteroids coming in from deep space, uh, and the moon is there sweeping up the ones that— most of the ones that do get through, with the result the Earth is hit FAR less frequently by bolides and large objects than ANY other planet that we know of in the Solar System. So, it's like a Goldilocks Planet in a perfect place, and I just wonder, and that gets me now to this idea, the basic idea of the book which is so enthralling, it's a little bit like the ancient aliens but it's much more complex than that and deeper than that folks, and we're going to get into that."

Solar Outbursts

That long quote is surprisingly coherent so far as most clips go on this show that I play for you, so let's get right to it. The first claim is that the sun is a yellow dwarf type star that is a weird yellow dwarf because most yellow dwarfs emit sterilizing bursts of gamma rays every few hundred thousand years. This is wrong.

The sun is classified as a yellow dwarf star. This means that its a yellowish color star and it's small relative to how big stars can get, usually thought to top off at 100 solar masses but more commonly 10 solar masses. Stars can also get smaller, the smallest for fusion being about 80 Jupiter masses which would equate to about 8% the mass of the sun. But our star is pretty run-of-the-mill so far's stars tend to go.

But, it doesn't emit bursts of gamma rays. Yes, it does emit gamma rays, but only as a normal byproduct of nuclear fusion, and the amount of light that it emits as gamma rays is minuscule compared to everything else, and it's constant, so that is definitely not what Whitley was talking about. Assuming he's talking about the gamma ray bursts that astronomers talk about, there is no astronomer who thinks that sun-like stars emit them.

Gamma ray bursts are something that we're starting to better understand, but when I was in college, they were still a mystery. The issue is that gamma-ray detectors would detect them, but by the time we could get a visible-light or other telescope in that direction, there'd be nothing to see. So when I was in college, dedicated programs were just coming online, including a space telescope, to try to sync up those kinds of observations to understand them.

Gamma ray bursts or "GRBs" themselves are very diverse, suggesting a lot of different causes. They can last anywhere from just milliseconds to several hours, giving you an idea of why it took dedicated programs to sync up observations from multiple kinds of telescopes. They are extremely energetic explosions that are often in very distant galaxies billions of light-years away, meaning they're even more energetic since we can actually see them.

Perhaps most importantly in this episode, the energy released in a TYPICAL GRB is as much energy in a few seconds as our sun will release in its entire, 10-billion-year lifetime. So sun-like stars CAN'T be the source of GRBs.

Now-a-days, we know that GRBs are caused by a few main things. First is the long GRBs which we think are caused by massive supernovae of really massive stars, at least 40 times the mass of the sun, in events called collapsars or hypernovae. These collapse into black holes and must also be rotating very quickly. They also must have low metallicity, meaning any element heavier than helium. And that's why they're rare.

There's more disagreement in the astrophysics community about the cause of short GRBs, but the favored model is the merger of two neutron stars or a neutron star and a black hole. Another idea is magnetar giant flares. A magnetar is a type of neutron star with an extraordinarily strong magnetic field — and neutron stars already have a strong magnetic field by default. These neutron stars could, in theory, emit incredibly strong outbursts of gamma rays.

Habitable Zone

The second claim is that Earth is in the exact center of the habitable zone, which is only 50,000 miles wide. This is wrong.

A star's habitable zone is based on a huge number of factors, but the basic idea is that this is the zone where life as we know it could survive, and so it is defined at a very basic level of where the water molecule can exist as a liquid. This varies based on atmosphere, and there are other issues, too, but that's the basic one we can use for now. If you're interested in more on that, e-mail because we discussed me coming on a few years ago to talk about the concept, but that hasn't happened yet.

In our solar system, the habitable zone is generally agreed to be somewhere from about Venus' distance from the sun almost out to Mars' perihelion, the closest distance that planet gets to the sun. Put in numbers, that's roughly 0.75AU to about 1.5AU, where 1AU is an astronomical unit, the average distance between Earth and the Sun. Which is about 93 million miles, or 150 million kilometers. That means that the width of the habitable zone is somewhere around 75% of an AU, or 70 million miles or 110 million kilometers wide. That's a bit bigger than 50,000.

But you don't have to believe me on that. You may think you need to be more conservative than astronomers. Okay, fine. We know that Whitley is wrong in his 50,000 mile number because Earth's orbit takes it from 147.1 million to 152.1 million kilometers from the sun, or 91.4 to 94.5 million miles, every year. That's a width of 5 MILLION kilometers, or 3.1 MILLION miles, almost 100 times bigger than Whitley claimed. And we don't freeze and burn during that time.

Lunar Origin

The next claim has to do with the moon, but I'm going to split that into two different ones. First up is lunar origin. I discussed the origin of the moon in detail in episodes 53, 89, and 105, so I'm not going to do that here. Suffice to say in THIS episode that (a) the fission idea for the moon - the idea that Earth and the Moon split from the same body - is not favored by really any scientist today, and (b) even if it were in favor, the idea that it came from the Pacific Ocean is one that hasn't been used in a century because we now know about plate tectonics which means the Pacific Ocean is only a few hundred million years old.

Moon's Life-Affirming Influence

The second part of the lunar claims was that the Moon helps promote life on Earth, or helps it to survive. If Whitley had just stopped there, I would have agreed with him 100%. Tides help mix waters which likely helped circulate nutrients for the first life, and the moon as a large gravitational body in orbit of our planet keeps our obliquity very stable.

Obliquity is the tilt of our planet's rotation axis relative to its orbit around the sun, and it's that 23.5° number most people know if they don't know necessarily what it's called. Because of the Moon, Earth's obliquity only varies by about ±1° over long timescales, and that stable tilt means we get regular seasons.

Contrast that with Mars, which has no large satellites, and Mars' obliquity goes anywhere from 0° to almost 90° over million-year timescales; its current obliquity is currently rather low for the average, about 25°.

But, unfortunately, Whitley did not go there. Instead, he claimed that it calms our winds. That's wrong. Earth's moon has really no bearing at all on Earth's winds. How could it, what would be the mechanism? The only methods I can think about is minor and another indirect.

The minor method is tides again, where tidal forces are observed acting on the atmosphere, but it's a remarkably minor effect. The indirect method is again tides, since tides have an effect on ocean currents, and ocean currents can influence winds.

Gas Giants and Projectiles Hitting Earth

The next claim could again broadly be broken in two, but I'm not going to for this discussion because it's more about impacts on our planet than separate claims about different effects.

Whitley started this claim by saying that the gas giants in our solar system helped to clear out the leftover material from planet formation and that helped prevent it from hitting Earth. This is true. But, it's also common. Based on our observations of the now thousands of known exoplanets, we know that giant planets are common, hence this would occur in most any solar system that we've seen.

The next part of it was that the moon sweeps up impactors that would hit Earth. The moon does have an effect, but it's generally thought to be minor. After all, the mass of Earth is, roughly speaking, 100 times that of the moon. Its surface area is about 16 times that of the moon. We're going to get hit more than the moon.

We are also not the least-hit object in the solar system. It is true that we have few impact craters relative to other bodies, but that's because we have active geologic processes that remove them. The only known solid object that has fewer craters is Jupiter's moon Io, whose surface is being constantly recycled by active volcanism due to the tidal pull between Jupiter and its other large moons stretching its core like taffy. It's possible that Titan also has fewer craters than Earth. I haven't done my own mapping, but based on numbers I've seen, there may be around 100 craters that Cassini was able to detect. Earth has around 170 known impact craters, but it's also 6 times more surface area, so per unit surface area, Earth has fewer. The reason for the few craters on Titan is its thick atmosphere and it also has active erosion processes.


And those are the four main claims that Whitley made about fine-tuning of our planet, and every single one was 100% wrong, or at least partly wrong. He was wrong about our sun — it's a quiet star and its kind is a quiet star and can't emit gamma ray bursts because gamma ray bursts would use up its entire energy output over its entire life. He was wrong about the habitable zone — it's 100 times wider than he thought and Earth's own orbit proves him wrong. He was wrong about the moon — while it does help life exist on Earth, it did not come from the Pacific Ocean and it doesn't do much of anything to Earth's winds, at least not directly. And, he was wrong about impacts on Earth — the claim about gas giants is correct, but not that Earth has the fewest impacts of any body in the solar system.

This isn't meant to pick on Whitley Strieber per se. Whitley just happened to make the latest version of these claims that I've heard many times before, and he presented them in a remarkably cogent fashion for his industry.

This is also a case that demonstrates well the two parts to investigating any claim: First, you have to make sure the claim is actually real. If it isn't, you can stop there, you don't even have to explain its implications because the claim itself may have no basis in fact. In this instance, with these examples, we can stop after step 1, without even going on to step 2.

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Comments to date: 1. Page 1 of 1. Average Rating:

Dave Regan   Oregon

9:16pm on Monday, November 27th, 2017 

I his first claim of gamma rays from sun stars is obviously wrong. I expect he was referring to the flares of red dwarf stars in their early life. (not what he said, but it fits his sentiment better.)

Habiable zone at 50 thousand miles. He stumbled here, and was trying to decide to say thousand vs. million. He chose wrong. 50 million would be reasonable(ish). Again, it isn't what he said.

The moon stabilizing the winds. I think he was going for the moon slowing down the rotation of the earth from a much faster speed via tidal interactions. He interprets the high rotational speeds to mean high winds. At least that's where I thought he was going.

Obviously, he is a crank, but I think some of the pieces you picked at might not be what he meant, even if it is what he said.

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