RSS Feed
iTunes Link

Episode 69: The Solar Neutrino "Problem"

Download the Episode

Recap: A problem for particle physics and solar physics sparked a somewhat technical argument by young-Earth creationists that our Sun is a young star, only a few thousand years old. Unfortunately for them, the problem was solved in 2001, but I'm getting ahead of my story ...

Answer to Retrodicted Puzzler to Episode 66: Congratulations to Parrot on the SGU boards for being the first to send in an answer. He identified four fallacies: False Premise, Begging the Question, and an Argument from Authority wrapped in a Non-Sequitur. The false premise was exemplified by, well, most everything he claimed. The Begging the Question is, for example, he stated, "a base frequency that tunes and balances the mind and body" assumes that the mind and body require balancing through some sort of frequency, or that some sort of frequency could even accomplish such a thing. It's the final statement that's the argument from authority wrapped in a non-sequitur, that NASA is researching it. Not only is the allusion to NASA an argument from authority, but it also isn't relevant to the claim that this would work, for one can claim that the US government funded psi research into remote viewing ergo it's valid. Same basic thing. I think Parrot did a nice job there. The only thing I would add, though it's not really a formal logical fallacy, is making $h¡‡ up.

Answer to Puzzler from Episode 67: Congratulations to Chew, again on the SGU boards, for being the first to come up with an answer other than, of course, Jan who suggested it in the first place. Chew's response is, "Comets are less dense so they will be decelerated quicker when they hit the atmosphere and will explode at a higher altitude. Comets also come in faster [and] on very elliptical orbits." I think it's this last part that give the two main ways to tell, other than having observed it before-hand or finding pieces of it. Comets are usually on highly elliptical orbits and their speeds, at Earth, are roughly 5x that of the average asteroid. When we clock how fast the object was going and work out its orbit, it's more consistent with an asteroid than a comet.

Answer to Puzzler from Episode 68: There was no puzzler in Episode 68.

Puzzler for Episode 69: I mentioned that it takes thousands of years for light produced in the Sun to reach Earth. Why is that?

Q&A: There was no Q&A for this episode.

New News, from Episode 81: Neutrino 'flavour' flip confirmed

  • New news this episode relates to episode 69, "The Solar Neutrino 'Problem.'" The jist of that episode was that the neutrinos that should form during fusion in the sun weren't detected at Earth, but when it was found that neutrinos could change type, all the neutrinos were accounted for.
  • The new result from a large collaboration of over 500 scientists shows that, while we've known for a decade or so that neutrinos could change - or oscillate - in some ways, we didn't know if they could in another way. This experiment shows they can. I know that may sound somewhat vague, but going into more detail to understand it would take several minutes, so I've linked to the article in the shownotes and if you're interested, head over and take a look.

Additional Materials:


Disclaimer: This is NOT an argument that most creationists still use because it has been [insert echo] solved by science. But, you can still find it on many young-Earth creationism websites without disclaimers that appear elsewhere on their websites saying not to use the argument.

Claim: The claim that they're not supposed to use anymore is that, until about 2001, there was a problem with particles emitted from the sun and arriving at Earth not being what they should have been. But, Creation Science™ could solve the problem by making the sun less than 10,000 years old.


To understand what's going on here, I need to take you through the main process of fusion that goes on in the Sun. We call it the "p-p chain," where "p" stands for "proton." A single proton is a hydrogen nucleus, where a nucleus is the center of the atom.

The first step is that two hydrogen nuclei, which are just two protons, smash into each other and merge to form a new single nucleus. But the nucleus is not made of two protons, it's made of a proton and a neutron. A neutron has a little bit less mass than a proton. So, in order to change from two protons into a proton and a neutron, a little bit of mass has to be lost. This is done by releasing both a positron, which is like an electron but oppositely charged, and by releasing a neutrino. This is the only step in the p-p chain that releases a neutrino, so I can stop there and move on with the solar neutrino non-problem.


Neutrinos, according to the standard model of particle physics, come in three different types, or "flavors," plus an additional three that are the anti-neutrinos. The term "neutrino" means "small neutral one" in Italian, and in physics they are written with the Greek lower-case letter nu, which looks like a v in English.

They have no electric charge, hence why they are called neutral electrically. And, until the 1990s, they were assumed to be massless, kind of like light. But, like light, they still have energy.

Unlike light, neutrinos are incredibly difficult to detect. They barely interact with matter at all, and the saying I heard when growing up is that a single neutrino could travel through a light-year-thick slab of lead and not interact with any of the lead atoms.

At Earth, the amount of neutrinos that hit us is about 70 BILLION per square centimeter per second. I took out a ruler and measured my hand ... that number means that there are about 10 quadrillion neutrinos streaming through my hand every second. And they don't interact. That's one of the reasons why, for a very long time, they were thought to have no mass.

I said at the beginning of this discussion that the standard model predicts - and we have detected - three different types of neutrinos plus their corresponding anti-neutrinos. The three types are the electron neutrino, muon neutrino, and tau neutrino. And despite the name "electron neutrino," it still has no charge.

What's mainly different about these elementary particles is their energy. I'm going to throw out some numbers here that I'll explain in a moment: The electron neutrino's energy is a maximum of 2.2 electron-Volts, or eV; the muon neutrino's maximum energy is 170 keV, and the tau neutrino's maximum energy is 15.5 MeV.

What does this mean? It means that the energy of the muon neutrino is about 100,000x more than the energy of the electron neutrino, and the tau neutrino is about 100x more than that.

The ability to detect these scales with their energy. So it's relatively easy to detect the electron neutrino, and in fact Wolfgang Pauli did so in 1930. The muon neutrino was detected in the late 1940s, and the tau neutrino wasn't detected until the mid-1970s.

Another important point about the energy is that's how we can figure out what kind of neutrino should be produced in the p-p chain when a proton turns into a neutron. By taking the difference in mass and scaling by the speed of light (E=m*c^2), the energy corresponds to an electron neutrino.

Testing the Models

So, the electron neutrino should be produced during the solar fusion process, and that's what we should see at Earth.

We can also tell how bright the Sun is, and we can measure the amount of energy from it that hits Earth. From this, it's really basic geometry that gets us to how much energy is made in the Sun per unit of time. From that, we can calculate how many p-p chain reactions need to take place per unit of time, like per second. And from that, we can calculate how many electron neutrinos should be calculated per unit of time.

And from THAT, we can calculate how many electron neutrinos should be passing through Earth per unit of time.

And from THAT, we can design an experiment to detect neutrinos, calculate from the Standard Model the likelihood that a neutrino would interact with the detector and hence be detected, and then see if the prediction matches what really happens!

Sounds simple, right?

If you don't want to go back and listen to the last minute or so, the basics of what I just said are that we have a model for how many of this neutrino should be produced, we can figure out how many should be detected in an experiment on Earth, and see if the experiment matches the prediction.

The first experiment to test this was in the 1960s. I'm not going to get into the details of how neutrino detection works because that's really a side-issue for this discussion. I'll have a few links up in the shownotes that talk about them.

What's important is that this first experiment from 50 years ago, designed to detect electron neutrinos, found that there were NOT the number of neutrinos predicted.

Experiments over the next several decades confirmed that there were NOT the number of neutrinos predicted. In fact, there were only about 1/3 of the ones predicted that were detected.

Since multiple different kinds of experiments were run by many different groups, the most likely problem is that the sun didn't behave as we thought. There were a few early attempts to alter the models of how the sun produces energy, like maybe somehow part of the core had shut down but since it takes thousands of years for the light to work its way out of the core but the neutrinos just take 8 minutes to get here, then we hadn't noticed it yet. But, advances in other fields of how to observe the sun showed that our models for how energy is produced in there are correct.

So we had a problem: Energy is made by the p-p chain, we should get a certain amount of electron neutrinos out of it, but we only find about a third of them. The only way this could happen, it was thought, is that the core of the sun is cooler (which independent methods of measuring it found was NOT the case), or that the experiment was wrong on Earth (but we had very different experiments and ways of detecting them that all had the same deficit).

Hence, the "Solar Neutrino Problem."

Creationist Argument

As tends to happen whenever there appears to be a "crisis" in science, creationists will try to come in and claim that if the universe is just about 6000 years old, that saves everything. And even if it doesn't, it helps save it and the rest is done by God. That happened in this instance.

As tends to happen whenever there appears to be a "crisis" in science, creationists will try to come in and claim that if the universe is just about 6000 years old, that saves everything. And even if it doesn't, it helps save it and the rest is done by God. That happened in this instance.

How exactly they do it while retaining any shred if intellectual honesty is beyond me, however, because they effectively do what I am terming, "observation mine." Kinda like quote-mining where you pick and choose parts of sentences that support your idea, young-Earth creationists would observation-mine, picking and choosing the most modern science that supports their idea but ignoring the modern science right next to it that refutes it.

For example, they accepted the parts of the standard model that say neutrinos are massless. They accepted parts of the standard model that are the energy levels of the neutrinos. They accepted the experiments that showed what the detected number of electron neutrinos were. And, they accepted the p-p chain in the sun that gives you the neutrino in the first place.

In order to accept these, they also have to accept the speed of light because that's how you get energy from mass and vice-versa. They also have to accept rates of radioactive decay because that's how many of the neutrino detectors work. But, as I talked about in past episodes on radiometric decay and will discuss in a future episode on their views of the speed of light, they reject these two things in other cases. You can't have it both ways.

Meanwhile, while accepting those other things, and accepting these things when it suits them, they then reject every single independent observation and method we have of figuring out how old the sun is, the composition of the sun, and how hot the core is. You see, they have to in order to then say that their solution to the solar neutrino problem is that the sun is in fact about 6000 years old. According to them, this then solves the solar neutrino problem because a younger sun would have less helium and have a lower core temperature which would mean there should be less neutrinos which is what we see.

In other words, something that was proposed by scientists in the late 1960s but rejected based on the observations that show we DO know how old the sun is, what it's made of, and how hot the core is.

Science Saves the Day

Moving back to the realm of science, I mentioned there were two basic ways to solve this: Either the model for the sun and fusion in it was wrong, or the experiments were wrong. But neither were.

But, this is a false dichotomy: A third option exists, and it falls into the category of a supporting theory that feeds into these other two things was wrong.

It had been assumed in the Standard Model that neutrinos had no mass. Without mass, they could not change type, or flavor (yes, the different types are called "flavors"). BUT, *IF* the neutrinos have mass, even just a teeny tiny bit, they they can oscillate, or change flavors, and based on various quantum mechanical properties when you observe any given neutrino, you may observe it as another. This was first proposed in 1968, and so the missing neutrinos could simply be the other kinds. They would also travel just UNDER the speed of light.

THAT is the solution to the solar neutrino problem. The electron neutrino is the lowest-energy neutrino and hence the easiest to detect. It wasn't until about 40 years after the first big neutrino detection experiments that a detector was designed to observe all three types -- the electron neutrino, muon neutrino, and tau neutrino.

The first experimental hints at this were from supernova 1987A, due to the difference in arrival time of the nuetrinos at a detector on one side of Earth from another being slightly less than the speed of light should have been. But there were so few counts that it was hard to draw any strong conclusions.

Next was in 1998 with a detector in Japan. They found that fewer neutrinos from below the detecter were found than coming from above. A way to explain this was that in the time and space it took for the neutrinos to travel through Earth and be detected at the bottom of the experiment, some had changed flavor, oscillating to one that it couldn't detect.

Then in 2001, at the Sudbury Neutrino Observatory in Canada, which had been retrofitted to detect all THREE types of neutrinos, they found all three types. In the right amounts to add up to all of the neutrinos that should have been produced by the p-p chain from the Sun.

In other words, we were right about the amount of neutrinos being produced from the sun, we were right in our experiments. But, the reason we only found 1/3 of the neutrinos is that en route to Earth, the other 2/3 had oscillated to a different flavor that wasn't detected in the same experiment until 40 years later.

So in one go, we solved one problem with astronomy and learned something else about particle physics, that the neutrino has a tiny bit of mass.

What this Demonstrates

I really like this topic because I think it's an excellent example of how science works and how pseudoscience doesn't work. Allow me to explain:

Scientists - not the creationists - identified a problem: Based on what we think we know of how energy is produced in the sun, and the byproducts of that energy production, we should be observing something specific at Earth. We're not.

The scientists then take the next step along the scientific method and come up with the idea that either our models of what's happening are wrong in some way, or our observations are wrong in some way. Or something else upon which the models rely are wrong in some way.

In this case, it was that last point. Neutrinos were not thought to have any mass, and so they shouldn't change from the sun to Earth. But, IF they DO have mass, then they can change. An experiment was designed to test this and found that prediction to be correct, thus solving the original problem and the idea of how energy is produced in the sun now has no issues. Unless you're an Iron Sun, Electric Universe, or follower of James McCaney ... all to be discussed in future episodes.

On the other side, you have creationists. They latched onto an apparent problem with the science of something. They muck around with the numbers, and - Hey! If the sun were only 10,000 years old, then it would have less helium and so if we wave our hands around we can get the numbers to work out and say it's young!

In other words, instead of continuing the process of science, they find the anomaly, go back to GodDidItRecently®, and stop there. And for a long time, this was a frequent argument among many young-Earth creationists.

And now that the experiments have been done and the problem solved from a scientific standpoint, that argument by creationists is completely nullified. It's even in the list of Arguments Creationists Should Not Use on several leading young-Earth websites.

The same thing happened when Kuiper Belt Objects were discovered in the mid-1990s when creationists had been saying for a long time that there was no source for comets therefore GodDidItRecently. Then after the Kuiper Belt was discovered, it turned into, there's no Oort Cloud because it hasn't been seen, therefore GodDitItRecently®. Go back to Episode 3 for more on that.

Besides moving the goalpost, this is a case where, at least in my opinion, when you hang your hat on God filling apparent gaps or non-observations or anomalies in science, and then those are filled, the role for your God becomes asymptotically smaller. I'm not a theologian, but to me, that sounds like bad religion. And that's why I think it's important to leave this main segment by pointing out that I'm not necessarily out to "get" religion, I'm here to point out when they drift into the realm of science to try to use it to bolster their claims, they fail time and time again.

Provide Your Comments:

Comments to date: 6. Page 1 of 1. Average Rating:

Stuart R   Boulder, CO, USA

1:48pm on Sunday, April 7th, 2013

Ciaran - yes, I was repeating a misconception I had from 3 years ago that just stuck with me. I'll make this correction in the next episode.

Stuart R   Boulder, CO, USA

1:47pm on Sunday, April 7th, 2013

Benny - Trillion, quadrillion ... what's a factor of 1000x between friends?

Ciaran   Dublin

10:19am on Saturday, April 6th, 2013 

One small correction: neutrons are a little more massive than protons, that's why they can decay to protons. Energy is released from fusion because the proton and neutron combined together has less mass than the two protons (or proton and neutron) separately.

Benny L   Stockholm, Sweden

3:35pm on Friday, April 5th, 2013 

Hey Stuart!

I've never had the pleasure and honor of meeting you in person (well, or any other way for that matter), but I imagine you'd be easily recognizeable from a distance, given your HUGE hands. :-)

If I'm not mistaken, you are a few orders of magnitude off when stating that there are about 10 quadrillion neutrinos zooming through your hand every second. Either that, or... well, let's just say you'd have a good career in the circus of this astronomy thing doesn't work out for you!

If I measure my own hands (that are large-ish, as I'm 1,88 m tall and unfortunately a bit over 100 kg), and being generous in assuming they are perfectly rectangular, they're about 11 by 19 cm, giving them an area of about 209 cm2 (pretend that's a "squared 2" :-) ).

That gives me about 209 * 70*10^9 == 1,463*10^13 or just under 15 TRILLION neutrinos. Which is a respectable number, I dare say, but compared to your 10 quadrillion... whew! I'm outclassed for sure. :-)

Now, I'm not a scien... read more »

Stuart R   Boulder, CO, USA

3:13pm on Wednesday, April 3rd, 2013

S B -- Try to re-download the file. This occasionally happens for people that it doesn't seem to download properly the first time.

S B   UK

2:30am on Tuesday, April 2nd, 2013

Stuart, I can't open the podcast 69. Nrmally it automatically oopens and plays..but it seems as if it might be corrupted. Ideas?

Your Name:

Your Location:


Your Comment:

Security check *

security image