My Response to a Creationist Solar Mass Loss Claim

by David C. Wise
Written September 2002

I have received a number of cold emails as a result of my creation/evolution pages. Most of them are just a link to a creationist site or a few typical "unanswerable" creationist questions, to which I reply (and answer) and I never get any reply back.

This case looked like it would be the same, but instead turned into one of those rare occasions where the creationist replied and we were able to carry on a discussion for a while. The young creationist (high-school) started off with a cold email containing two questions, the second one of which was:

As any good scientist will tell you, the sun burns half of its mass every year. If you multiply the sun's mass by millions (even though science says it is in the billions) the sun will be so incredibly huge it will stretch out past Pluto. And if you say that the planets would stay close to the sun as it shrank, then why don't the planets still move closer?

In the twenty years that I've been following creation/evolution, that is the most outlandish and most obviously false claim I have ever seen. I was truly amazed to see it being used.

The following section contains the part of my response that answers that question.

My Response to the Question

>>2. As any good scientist will tell you, the sun burns half of its mass every year. If you multiply the sun's mass by millions (even though science says it is in the billions) the sun will be so incredibly huge it will stretch out past Pluto. And if you say that the planets would stay close to the sun as it shrank, then why don't the planets still move closer?<<

Sorry, but I really had a hard time understanding what you were trying to say and ask here. It is obvious that it is a creation science claim, so could you please give me the source of this claim?

Given my cynicism that you might be a typical creationist (see discussion above), this will be my only chance to respond and so I will take a stab at interpreting it. Here is what I think that you are trying to claim. Please correct me if I misunderstood.

You are trying to claim:

1. In burning its fuel, the sun loses one half of its mass every year.
2. Multiplying the sun's current mass by millions or billions is supposed to tell us what its mass had to have been that many millions or billions years ago.
3. As the sun's mass diminishes at this incredible rate, the orbits of the planets should become proportionately smaller, such that the planets move in closer to the sun.

Did Kent Hovind come up with this one? Because this really is one of the worst creationist howlers I have ever seen. I'm sorry, but it is even worse than the claim that "evolutionists" believe that ancient Egyptians and Mesopotamians were ape-men.

First, let's look at that second part of the claim. Consider these figures for the mass of the sun:

Astronomy textbook, 1972: 1.99 x 10^30 kg
Collier's Encyclopedia, 1991: 1.96 x 10^30 kg

I would tend to attribute the difference to observational error. But still, you would have expected the sun's mass in 1972 to have been 19 times greater, 37.81 octillion metric tons. It wasn't. Nor should your claim have expected it to be, but rather your claim should have expected it to be 512 times greater.

You see, the math is wrong. If we were to assume loss of half of the sun's mass every year, then each year it would have been twice what it was the year before. You are expressing an arithmetic progression, whereas in reality it should be geometric (review Malthus).

Here is the formula that expresses what the sun's mass would have been for any year in the past, according to your model:

m0 = sun's mass at present
t = number of years that we are going back (eg, starting from 1991 and going back to 1972 would be 19 years)
m = the sun's mass at that past time

m = m0 * 2^t (past mass = current mass times 2 raised to the number of years)

Therefore, given a 1991 solar mass of 1.96x10^30kg, your model would have predicted a 1972 solar mass of 1.03x10^36 kg.

Of course, it was nowhere near that massive. Would you care to explain this discrepancy?

On the first part of your claim, where did they get the idea that the sun is losing half of its mass every year? Does your creationist source give you a reference to a scientific source? I would really like to have a look at that source, because this part of the claim does not make any sense at all. The claim says "as any good scientist will tell you". Please, name some of those scientists and where they had said that the sun is losing half of its mass every year. I really would like to see what they really said and what they were really talking about.

For that matter, that would be a most excellent exercise for you -- verify your creationist source's statements by researching back to their sources. If you read my updated section on the moondust claim, you will see that creationists will claim sources that they never even looked at, but rather they repeat and spread each other's claims like urban legends. A serious and honest researcher always tries to go back the PRIMARY SOURCE instead of blindly trusting what secondary and tertiary sources claim that primary source had said.

The sun's mass is 1.99 octillion metric tons (1.99E+27, which is computerese for 1.99 times 10 raised to the 27th power, which is about 332,000 times the mass of the earth). You say that this year, the sun will lose half of that, or about 995 septillion metric tons (9.95E+26). Where does that 995 septillion metric tons of solar material disappear to? And if the sun were losing that much mass EACH YEAR, then it would have had grave consequences that we could not have possibly remained ignorant of for all these centuries. How do you explain that that had escaped our notice?

For example, according to Kepler's Equation, the period of a planet's orbit is inversely proportional to the square root of the mass of the sun (obviously, for a planetary satellite substitute the planet's mass). So, if the sun's mass goes to one-half of what it was, the period goes to 1.414 times what it was. For the earth, that translates to our year going from 365.2524 days to 516.467 days. And to 730.28 days in the next year. And to 1032.62 days the year after that. And to 1460 days the year after that. And so on. In a single decade, the length of the year would have grown 32-fold. In a century, by a factor of 1.126 quadrillion. I think you get the picture. Have we noticed such a radical change in the length of the year? No, we have not.

The effects on the length of the year was based on keeping the size of the earth's orbit constant. What if we were instead keep the length of the year constant and allow the size of the orbit to change? The size of the orbit is directly proportional to the cube root of the sun's mass. Halving the sun's mass every year changes the size of the orbit by a factor of 0.7937 each year. By .0992 in a decade. By .0098 in a century. Yet again, radical changes which we have mysteriously not noticed. Besides, an orbitting planet would not respond to the sun's loss of mass by moving in closer, but rather the opposite -- as we will discuss below.

But what happens to that mass? If you say that that mass gets "burned up", then please be more specific. When something burns up in our everyday experience, it undergoes rapid oxidation. That means that some of the atoms in the material, mostly carbon in class A fires, combine chemically with oxygen to form new compounds and release energy. However, all the mass that the system started with is still there -- every single atom can be accounted for. No matter was destroyed in this fire. It only looks that it "burned away" and ceased to exist because the gaseous compounds that were formed took the missing mass away "up in smoke".

Does the sun "burn" through oxidation? No, it does not. Please review your basic astrophysics. The sun "burns" hydrogen nuclei in its core, forming helium nuclei. Actually, the reaction chains are a bit more complex than that, but I spare you the details here. The total mass of the nuclei going into the reaction is very close to the mass of the nuclei and particles coming out. That small loss is from matter-to-energy conversion which is the source of the energy produced by the reaction. That loss is very small; as Strahler remarks: "Over long periods of time the mass lost by the total conversion process is an extremely small part of the original hydrogen mass."

Maybe that mass is ejected from the surface of the sun. 995 septillion metric tons (9.95E+26) in the baseline year. 2.725 septillion metric tons a day. 113.5 sextillion (1.135E+23) metric tons an hour. 1.89 sextillion metric tons a minute. 31.5 quintillion metric tons (3.15E+19) a second. And the rates were twice that the year before, four times that the year before that, eight time that the year before that, 1024 times that a decade before, 1,048,576 times that two decades before, etc.

Assuming that all that mass spews forth equally and uniformily in all directions, at 93 million miles away the earth would receive 454 trillionths (454E-12) of the total mass ejected from the sun. Every second, the earth would be bombarded with 14.3 billion metric tons (14.3E+9), which comes to 451.7 quadrillion metric tons (451.7E+15) a year. And, of course, those amounts would double every year we go back. We measure only about 50,000 tons of meteoric matter hitting the earth every year. Surely such immense amounts of STELLAR material hitting the earth would have been noticed, yet it has not been noticed. Now, I'm not completely sure of this, but I would think that that amount of stellar material hitting the earth at high speed would have stripped our atmosphere away and scoured and etched the surface of the earth clean, especially in times past (eg, at a rate of 14.3E+509 metric tons a second 2000 years ago). Apparently, that did not happen.

Now for the third point of your claim: "And if you say that the planets would stay close to the sun as it shrank, then why don't the planets still move closer?"

Well, for one thing, we don't see any noticeable variation in the size of the planets' orbits because the mass of the sun, which directly affects the size of the orbits, has not changed noticeably.

Another thing is that such loss of solar mass as you claim would have the opposite effect on the planets' orbits than you describe. As the mass diminishes, the planet would move out into a higher orbit. Which, by the way, we also do not see happening.

OK, I'll get a little technical here. Throughout a planet's orbit, a balance is maintained between its distance from the sun and the speed at which it is travelling. Closer in, it moves faster and farther out it moves more slowly. You should recognize this as Kepler's Second Law which states that equal areas are swept in equal times. In orbital mechanics, this is described as the Specific Energy of the orbit:

E = v^2 - GM/r

The Specific Energy of the orbit remains constant throughout the orbit. In order to change to a different orbit (AKA perform an orbital maneuver), you change the Specific Energy -- increase it to move to a higher orbit or decrease it to move to a lower orbit. At present, the only way we know how to do this is to change the velocity (v).

But you are talking about fiddling with the mass of sun (M). The formula tells you what will happen. The velocity (v) and the distance from the sun (r) don't change ... yet. As you can see, decreasing the sun's mass causes the Specific Energy to increase. And when you increase the Specific Energy, you move into a higher orbit. That is to say that the planet would move out FARTHER AWAY FROM THE SUN.

That is the direct opposite of what your claim says. I would like for you to explain why we would expect the planets to move in closer to the sun as its mass diminished.

The Creationist's Response

He thanked me for responding and admitted that the questions were weak. He said that he had gotten the questions from friends, but didn't know enough to evaluate them. He said he passed them on to me, because, judging from my site, I would probably be able to answer them.

Curious about the creationist source of that claim, I asked that he get that information from his friend. He replied that he could not, since he had gotten that claim from a Christian youth minister at a week-long retreat and he believed it unlikely that he would ever see the guy again.

My Opinion