When I stay up late to work, I usually switch in NPR’s “Day to Day” program. It’s taped earlier in the day, but here on KQED airs late at night. They were reviewing listener letters concerning a piece criticizing extreme religions and also criticizing the behavior of self-labeled “moderate Christians” as not being all that moderate. I don’t want to write about this… I didn’t hear the original interview. However, I can comment on what one listener wrote.
Paraphrasing, the listener wrote that “Scientists are often as dogmatic in their beliefs as those they criticize. Take dark matter. Scientists say that it’s required to explain their observations, but you can’t see it. How is that any different from belief?”
Well, that’s easy: dark matter is a hypothesis, one with testable consequences. For instance, it was postulated because of discrepancies in galactic rotation curves. A dark halo of matter surrounding a galaxy explains this discrepancy, since it alters the matter content of the galaxy and thus its rotation. Such an observation has consequences: if two galaxies collide, dark matter will get ahead of all the normal matter because it suffers far fewer interactions. Thus, the advancing front of dark matter can be imaged as it lenses light, and the visible matter can be imaged using its radiation output. This is exactly what has been observed to very high precision just a few months ago, another piece of evidence that it’s really *dark matter* and not just some new gravitational interaction.
It doesn’t end there. Dark matter is a particle, one which is required to have a interaction rate consistent with weak nuclear interactions in order to have properly “frozen out” of interactions in the early universe. Thus, it would produce a nuclear collision in the lab consistent with a weakly interacting, massive particle boinging off an atom. This hasn’t been seen, but is being looked for. Particles are also the speciality of colliders, and we might produce dark matter at future machines like the Large Hadron Collider, or an International Linear Collider.
So here’s my point: I have nothing against religion, but don’t ever confuse religious belief with scientific belief. I only believe in testable phenomena in the natural world, and dark matter is a hypothesis which has stood the rigor of experiment and observation and requires further testing to reveal its properties. The holy trinity, the resurrection of Christ, the nature of evil, miracles – these are all part of a belief system, religious tenets that cannot be tested with repeatable methods. I am afraid this listener is way off base: science believes what it believes because it works, and anybody can try it and verify it for themselves. It’s fundamentally distinct from religion. This is just another example that as scientists we have really failed to communicate the nature of science.