Galactic Interactions

Creationism is not like belief in the virgin birth or the bodily resurrection of Christ

Posted on July 18th, 2009 — permalink

There are some out there who assert that a belief in God is not compatible with accepting science. Some try to put a finer point on it; they assert that belief in either the virgin birth of Christ, or the bodily resurrection of Christ, is not compatible with science. I want to argue that it is.

First, I do not mean to assert that I personally believe in either. I have addressed the latter (bodily resurrection) in a blog post several years ago that is currently offline as a result of a dead disk. I’ll dig up the text of that and repost it here at some point. Short form: my answer to “did the bodily resurrection physically happen?” is “probably not.” Believe it or not, I am not alone among Christians in thinking that. However, it is reasonable to hold that belief while accepting science, without any need for hypocracy. It’s not consistent with “philosophical materialism”, no, but that’s a question of philosophy, not of science.

Some say that the scientific world view is not consistent with miracles. The reason is that the hypothesis that supernatural intervention happens has not stood up to scrutiny. There is no scientific evidence for it, and in the centuries in which we’ve been doing science, if it was happening we would have seen the evidence for it. What’s more, many things that were previously believed to be the fiat of God have come to have naturalistic explanations (e.g. the ignition of the Sun, the origin of the human species). So, science would seem to rule out miracles.

In fact, it does not, and any scientist who is being careful enough, and precise enough in his language, will say that. Science certainly gives no reason to believe in supernatural intervention! And, it gives many reasons to believe that supernatural intervention is an obsolete concept. However, as with many things that we do not detect in a scientific experiment or an observational program, science doesn’t rule out miracles; it merely sets an upper limit on their frequency. In other words, miracles (in the form of supernatural intervention) must happen extremely infrequently and irregularly to be consistent with the body of scientific observations.

Consider creationism. Creationism makes factual claims about the creation of the Universe (created in 7 24-hour days a few thousand years ago, with a specific order of events) and about the origin of the human species (created in its current form by God). These factual claims are false; we know them to be false, because we have extensive scientific evidence that points to other explanations.  Creationism is wrong, and belief in creationism is not consistent with accepting modern science.

On the other hand, consider the bodily resurrection of Christ. Now, we know that biological organisms that have died and stayed dead for three days decay enough that they cannot be revived. (It may well be that one day we will revive some of the cryogenically frozen people we have right now, but I think we can all agree that Jesus was not cryogenically frozen.) However, the bodily resurrection of Christ is a singular event. To believe in it is to claim that once, one guy, was bodily resurrected. (Let’s leave Lazarus out of this for simplicity.) Believing in the bodily resurrection of Christ does not claim that this happens regularly. What’s more, this belief does not make any claims that contradict any scientific evidence we have. It says that once, there was a miracle, and something that cannot happen according to our understanding of biology, did happen.

Could this be disproved? Probably not. I seriously doubt that if we found the remains of Jesus that we would be able to convince ourselves to any reasonable probability that that is what they were. Likewise, with the virgin birth, if we were to somehow find the remains of Jesus, Mary, and Joseph, perhaps we could do DNA comparisons to find out of in fact Jesus is carrying Joseph’s DNA. (Interesting theoloigcal aside: he’d better be if he’s of the house of David, but then again, I’m not writing about inconsistency in the Bible… inconsistency in the Bible is well established.) But, again, this has not been done, and indeed I would be very surprised if we were able to collect the samples (or, invent the time travel) that would allow us to do that test.

Science tells us that miracles really cannot be happening very often at all. But it sets an upper limit, it does not tell us that miracles never happened. The methodology of science requires us to omit miracles in our explanations; something we cannot explain through naturalistic means remains an open question, at least for the time being, to science. Science tells us that the creation story in Genesis is not history, but it does not tell us anything directly about the specific bodily resurrection of Christ or the specific virgin birth of Christ. Science does not have a mechanism for it, so if it happened, it was miraculous, and outside science as we understand it. Science gives no reason to believe in miracles, and indeed convinces us that they are not happening with any regularity at all. However, because we cannot absolutely rule them out, it is not inconsistent to believe that those specific miracles happened, while accepting the results and methodology of modern science.

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How much Dark Matter do you hold in your hands?

Posted on July 9th, 2009 — permalink

Via a Cosmic Variance blog post, I found this astro-ph paper by Catena and Ulio that claims the local density of Dark Matter is 0.39 GeV/cm3.

What does this mean?

Well, first, you may object that GeV is a unit of energy, so really what we’ve got here is an energy density of Dark Matter, not what most of us mean when we say “density” all by itself (which is mass density). Physicists, however, know that converting between energy and mass is so easy (via E=mc2) that they will very often, especially when talking about fundamental particles, cite masses in energy units. Divide by the speed of light squared to figure out that this is a density of 6.9×10-25 grams per cubic centimeter.

Second, “local” means “in our area of the Galaxy”. Dark Matter clumps on scales of hundreds of light-years, at the smallest, so if you’re looking on a scale smaller than that, it’s going to look smooth. It’s similar to our atmosphere; if you climb a mountain and get five miles above sea level, the air will be noticably thinner. But, if you go up just a few meters, you’re not going to notice any difference in the density of air.

What is the density of air? Well, if you believe Wikipedia’s Answer (and you should in this case), it’s about 0.075 lbm/ft3… or, in more reasonable units, 0.0012 grams per cubic centimeter. (That’s at room temperature and standard sea level pressure.)

And, while we’re at it: the density of Dark Energy in the Universe is about 75% of the critical density, the critical density being 3H02/8πG, or 9.7×10-30 grams per cubic centimeter (for a Hubble constant of 72 km/s/Mpc).

Right.

So let’s put this all together. Cup your hands. That makes a box roughly 5cm on a side, or 125 cubic centimeters in size. In your hands, you are holding:

• 0.15 grams of air
• 8.7×10-23 grams of Dark Matter
• 9.1×10-28 grams equivalent of Dark Energy

Strictly speaking, “holding” isn’t the right term, because the Dark Matter particles are passing right through your hands as if they weren’t there… but at any one moment, that’s how much Dark Matter is on average within the box you make by cupping your hands. (Air is coming in and out as well, because you probably have cracks in the box you make, but it doesn’t pass through your hands.) And, it’s hard to say whether Dark Energy is passing through your hands, or is a property of the vacuum and as such it is just how much energy density is there as a result of the volume you’ve cupped, but you get my drift.

Oh, and I suppose I should mention that every second, about 140 million neutrinos from the Sun pass through your cupped hands (based on the neutrino flux cited at this page from HyperPhysics). However, they’re going so bloody fast (very close to the speed of light) that at any moment, there’s only about a 2% chance that one of those neutrinos is right then within your hands.  (A similar consideration is probably true with Dark Matter particles, but I’d need to know the mass of said Dark Matter particles (nobody does), and I’d need to know their velocity (there are estimates, but I haven’t tracked them down) to actually give you numbers.)

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On Science, Religion, and Compartmentalization

Posted on July 8th, 2009 — permalink

Sometimes in the debates about whether or not it’s OK to be religious if you’re a scientist or somebody who accepts science, some will say that those who are scientists but also religious “compartmentalize”.  The implication is usually negative, and sometimes is explicitly described as walling off your scientific good sense when considering religion, and walling off the doctrines of your faith when considering science.

Of course, such a simplistic picture is far from the truth.

The truth is, though, that physicists already compartmentalize, even within Physics! Consider fundamental physics. We have two extremely successful theories, which have stood up to every experimental test we’ve thrown at them: Quantum Mechanics (QM) and General Relativity (GR). Quantum Mechanics does a great job of describing the behavior of atoms, molecules, subatomic particles, solids, and so forth.  General Relativity does a great job of describing the behavior of gravitating systems, such as the orbit of the Earth, the Solar System, the Galaxy, and the Universe. However, we know that they can’t both be right, because when you get into the regime where you need to consider both– a regime where densities are so high that you can’t ignore gravity even on small scales, and where you can’t ignore quantum mechanics when doing gravity– everything breaks down.

So what do we do?  We compartmentalize.  When dealing with gravity and the evolution of gravitational systems, we use GR, a continuous theory, and don’t worry about QM.  When dealing with the interactions of particles that require QM, we don’t include gravity in those interactions at all– at most, we may do QM on a curved spacetime background.  And, we admit that we just don’t know what happens where the two intersect.  There are some– such as string theorists– who are trying to work in the region where the two intersect, and, tellingly, there are other scientists who argue that what string theorists are doing isn’t really proper science.

Given that physicists compartmentalize themselves, it should be reasonable to suppose then that a degree of compartmentalization is not only necessary, but eminently reasonable and rational when dealing with science and religion.  I don’t mean “on Sunday, I believe God created humankind in its present form, and on other days I believe in evolution.”  That’s a pathological compartmentalization.  What I mean is that we know there are some things at which science excels describing, specifically the mechanisms of the natural world. And we know that there are some things addressed by religion, and by processes that cannot be described as scientific– specifically, the existence of God (there being no scientific reason to suppose God exists), human spirituality, morality in the context of a traditional belief system, and faith. Religion may hold no meaning or use for some, and that’s fine. But for people for whom it does hold meaning, there are clearly realms that religion can address which science cannot. Likewise, there are clearly realms that science addresses and which religion has tried to address, and where science has without exception proven to be superior.

So we compartmentalize. If we’re talking about the processes of the natural world, we look to science, because science has proven over the centuries to be the right “way of knowing” to understand those processes, make predictions about them, and harness them. If we’re talking about spirituality and faith, we look to religion, because the sorts of questions one asks there by and large aren’t even meaningful scientific questions. And, unsurprisingly, there may be areas of grey overlap, areas where we aren’t sure whether science or religion fully applies. As we understand these areas better, we may come to understand that something we once thought ineffable is in fact well within the domain of science. So we adapt, and adjust our compartments.

Just as it’s entirely possible to be a completely consistent physicist while using both GR and QM, it’s entirely possible to be a completely consistent rational person while accepting the roles of both science and faith in your life. The key is understanding where each applies, thinking creatively about how they overlap while understanding that it will be controversial and hard to decide, and being willing to adapt your understanding as the human race learns more.

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