In defense of scientism

On this 48th anniversary of the Apollo 11 moon landing, I want to talk a little bit about science, and how it, in principle, can apply to nearly every subject in life.

The word science is derived from Latin scientia, and earlier scire, which means “to know.”  I am, as you might have guessed, a huge fan of science, and have in the past even been a practitioner of it.  But science is not just a collection of facts, as many have said before me.  Science is an approach to information, and more generally to reality itself, a blend of rationalism and empiricism that calls on us to apply reason to the phenomena which we find in our world and to understand, with increasing completeness, the rules by which our world operates.  Personally, I think there are few—and possibly no—areas into which the scientific method cannot be applied to give us a greater understanding of, insight into, and control of, our world and our experience. Continue reading

What Are Black Holes?

[Another reprinted article]

A very old friend of mine—that is, one I’ve known a long time, he’s no older than I am, and I hope I don’t yet count as “very” old—suggested that I write an article about what exactly black holes are. So, I thought about it, for all of about two seconds, and realized that black holes would be a great topic for a general science article.

So, what are black holes? Well, in their most common form, black holes are the final remnants left behind after the deaths of the most massive stars. You see, during their ordinary, active lifetimes, stars are at a constant balance point between the force of gravity that tends to make them contact, and the force created by nuclear fusion and its consequent heat, that makes them tend to expand. This balance is maintained for a very long time…though interestingly, the length of time is inversely proportional to the size of the star. That is to say, the bigger the star is, the shorter its lifespan.

Sooner or later, though, every star will run out of its nuclear fuel and won’t be able to provide enough internal heat to keep from collapsing further. There’s usually a sort of contraction and expansion phase as stars get near this stage, and it’s during these times that especially the bigger stars start fusing heavier and heavier elements…but that’s really an issue for another article entirely. In any case, when a star runs out of usable fuel and gravity is no longer opposed by fusion, the star collapses. In some stars this collapse is so powerful and releases so much energy that a “supernova” occurs, a HUGE stellar explosion, where a lot of the star’s matter gets shot back out into interstellar space. This is how every element we know of other than hydrogen, helium and lithium came to be.

Now, depending on how big the star is to start with, when it collapses it will have one of only a few possible fates. Since gravity is dependent on the mass of the star, smaller stars will have less of a contracting force, and they—as our sun is expected to do—become white dwarfs. Gravity shrinks them down until their individual atoms are only separated by the quantum mechanical forces between the electrons (not the electrical repulsion, but the simple resistance electrons have on a quantum level to being too close together). This is about as densely packed as atoms can get and still be atoms. Our sun will probably shrink until it’s about the volume of one of its rocky inner planets like the Earth…although the Earth will almost certainly have been incinerated by the sun before that ever happens. Still, you get the idea.

A star that’s maybe two times the mass of the sun will have enough gravity that the electron forces won’t hold it up. Only the nuclear forces will be strong enough to resist this much gravity. These stars are among the ones that become supernovas, in part because of the tremendous energy released in this collapse that overcomes electron repulsion. The gravity of these stars is so huge that it squeezes the former atoms all in on themselves, sort of mashing the protons and electrons together and creating a huge ball of neutrons…a neutron star. This is about as dense as matter can get in a form that we can recognize as being made up of any kind of individual particles. What you’re left with after this collapse amounts to a single gigantic atomic nucleus…though without any protons and an unthinkably large atomic mass. It’s so heavy and the gravity is so huge that any human—or indeed any other unfortunate entity of normal atomic constituents—would be squashed immeasurably flat on its surface.

It would at least be a pretty fast death though.

Now we come to stars that start out at about three times the mass of our sun or more. When these star collapse, there’s nothing even nuclear forces can do to resist the gravity, and in fact, no known force can resist the collapse. These stars become black holes.

There’s a bit of trouble in describing what really goes on inside a black hole. According to general relativity, the mass of the star becomes compressed to an infinitesimally small and infinitely dense point called a singularity. Now, scientists are pretty sure this isn’t exactly accurate, since infinities are usually not literally achievable within the universe as we know it. Also, a truly infinitesimally small concentration of matter would violate the Uncertainty Principle, which is a law of nature that seems every bit as immutable as gravity. So here in the heart of a black hole we arrive at the notorious point of conflict between general relativity and quantum mechanics. I’m not going to try to explain how that conflict is to be resolved, because so far no one knows.

One reason why it will be hard to resolve this conundrum is because black holes are, well…black. The reason they are called black holes is because when gravity is that strong, even light can’t escape it. Yes, gravity effects light, though for anything short of a black hole that effect tends to be unnoticeably tiny. Yet the principle of why a black hole is black is fairly simple. It has to do with escape velocity.

Escape velocity is a measure of how fast something has to be going when leaving the surface of a body such as a planet or a star or a galaxy in order for it to fly completely away from the body and not remain at least in orbit (or come crashing back down on the head of the people below). From the surface of the Earth, you’d have to throw something upward with a speed of about 7 miles a second (ignoring air resistance) to keep it from coming back down or getting stuck in orbit. That’s pretty fast, but it’s TINY compared to the speed of light (about 186,000 miles per second).

Then again, the Earth is also really tiny, on the scale of stars. A very large star that has collapsed completely can have a gravitational pull so powerful that its escape velocity is greater than the speed of light. Well, so far as we know, light is still the fastest stuff in the Universe (rumors about neutrinos notwithstanding), so if light can’t escape from that gravitational field, then NOTHING can. That’s why black holes are black.

The blackness of black holes doesn’t just stick around right at that tiny point called the singularity. The gravity is strong enough that any light—and thus anything else as well—that gets closer than a certain distance to the singularity will never be able to escape. That distance from the center of the black hole defines a sphere of inescapability called the Event Horizon, or just the Horizon. This is a good name, because the horizon on the surface of the Earth is the point you can’t see past because of the curvature of the Earth, and the Horizon of a black hole is the point no one and nothing can see past because of the curvature of space-time (in other words, gravity). The size of the Horizon of a black hole is based simply on its mass. As more matter falls into a black hole, the horizon grows…though what exactly happens to the singularity in the center is unknown, and may remain so forever, since even in principle there’s no known way to get information from inside an event horizon.

Though they are all very similar in character, black holes come in a lot of different sizes (by which I mean their masses and the areas of their event horizon are different). There are “ordinary” black holes that are the remnants of large stars. There are also “super-massive” black holes, believed to be at the center of most galaxies—including ours—and which have the mass of millions or even billions of suns.

Theoretically, there may also be very small black holes with the masses of mountains, which might have been formed during the early Universe by the enormous pressures associated with the big bang. These black holes wouldn’t so much have collapsed as have been squeezed inward, and they wouldn’t have to have a very huge amount of matter. Yes, you can make a black hole that way. Well, YOU can’t, and I can’t but it’s theoretically possible, though not demonstrated. Still, some relatively small black holes could still exist out in the Universe, remnants of the tremendous forces unleashed when the Universe began.

There even could be submicroscopic black holes created by VERY energetic collisions of fast-moving particles, as in very large accelerators or in cosmic ray collisions. These would be black holes whose Horizons are on the size-order of subatomic particles. These are nothing to worry about, by the way, because—and this is something many people don’t know—black holes don’t last forever. They have a limited lifespan due to a quantum mechanical phenomenon called Hawking radiation (yes, it’s named for THAT Hawking). This describes the fact that all black holes are actually radiating particles and photons from just outside their Event Horizon. I’m not going to go into how that works right now (it’s not all that difficult to understand, but it would take quite a bit of explaining), but it means that the mass of a black hole does go down over time and eventually it will disappear, like water boiling out of a pot. What’s more, the smaller the black hole is, the faster it evaporates. Any black holes made accidentally—or deliberately—in particle accelerators would be so small that they’d evaporate before we could even directly tell they were there. Such black holes may pop into existence in the upper atmosphere every day…many times a day…when highly energetic cosmic rays hit the earth. So don’t freak out about CERN making a black hole that would swallow up human civilization. If that was going to happen, it would be happening several times every day at least, in the sky above our heads.

Well, I hope this article answers at least some questions about what black holes are, as well as giving some related and interesting information. I’ve left out a lot, but I know I’ve also covered things at a bit of a breakneck pace. If there’s anything that’s unclear or confusing, please let me know. I’m happy to receive constructive criticism on this most destructive of topics.

And to my very old…well, to my “long-time” friend who suggested this article: I hope you found it helpful.

Diabetes For Beginners – Part 1

Diabetes is an illness of which I suspect almost all adults in America are aware. I also suspect that most people know that it has something to do with high blood sugar and that having high blood sugar is a bad thing. Still, I imagine there are a fair few people out there who haven’t really got a lot more understanding of it than that—including some people who have the disease—because they haven’t really had it explained to them in terms they can follow. After all, doctors—of which I am one—don’t often take the time necessary to make sure that their patients fully understand the ins and outs of a disease process. Partly this is because, when one understands something on a very complex level, it seems like it’s going to take serious effort to explain it to someone who doesn’t have the same educational background. However, I think this is a failure of imagination and a bit of mental laziness on our part as doctors. The Nobel-Prize-winning physicist Richard Feynman used to prepare “freshman lectures” about physics subjects when laypeople asked him about topics they didn’t understand. If he found that he couldn’t prepare one, he recognized that failure as an indication that the subject wasn’t well-enough understood!

I just love that philosophy and attitude. So, since Diabetes in general is pretty well understood, I’m going to try to give a “freshman lecture” here on Diabetes.

First off, “Diabetes” is actually only part of the name of the disease we’re going to be discussing. The full name of the disorder is “Diabetes Mellitus” and this diagnosis is then subdivided into Type 1 and Type 2. The term “Mellitus” serves to differentiate the common disease known as Diabetes from the far-more-obscure disorder “Diabetes Insipidus,” which I will not really be discussing here.

You see, the word “Diabetes” is a Late Greek word meaning “excessive discharge of urine.” That’s originally all the word referred to, since that is the most noteworthy presenting problem in both kinds of Diabetes. The meaning of the second words in the disease names is going to gross a few people out, and that’s completely understandable. You see, “Mellitus” means (more or less) sweet-tasting, whereas Insipidus—and this will be obvious when you think about it—means “tasteless”.

Sweet? Tasteless? What is sweet or tasteless?

The answer is: That excessive discharge of urine. Yes, in the old days, one way they used to diagnose things was to taste the urine, and the urine in Diabetes Mellitus tasted sweet. Why? It tasted sweet because it was just full of glucose.

Well, urine is not SUPPOSED to be full of glucose! Nature has designed our bodies to want to hold on to glucose, either so we can use it directly as fuel or convert it into one or another storage form that we can use for energy later. Nature doesn’t deal very kindly with creatures that waste precious energy…when survival is at stake that’s a really bad strategy. So the kidneys ordinarily filter the glucose out of urine before it’s passed to the bladder for elimination. Only when the glucose is quite a bit above normal range is the kidney’s ability to do this overwhelmed, and sugar (glucose) starts to spill into the urine and be wasted.

So, how does the blood sugar get so high? Well, ordinarily, the level of sugar in the blood is pretty tightly controlled, mostly by the actions of two major hormones: glucagon and insulin. Most people who have heard of Diabetes have probably heard of insulin. Insulin is a type of hormone called a peptide, which means it’s a small, clipped version of a protein. It’s produced in the pancreas by a group of specialized cells called beta islet cells in an area called the Islets of Langerhans. The name isn’t really that important, except that things have to be given names so we know what we’re talking about when we’re talking to each other. The cells in the pancreas that make insulin were first described by a scientist named Paul Langerhans, so they got named after him. That’s how it works with a lot of obscure medical terms.

Insulin is secreted (released, in other words) by the islet cells in response to the sensed level of glucose in the blood. The more glucose there is, generally, the more insulin is released. Why is this necessary? Because the cells of the body only take up glucose when they’re stimulated to do so by the action of the hormone insulin. Insulin is, quite literally, the signal that tells cells to activate the machinery they use to take glucose in, after which they can digest it for energy to run their metabolism, or they can store it for burning later. So, when we eat and our digestive systems bring glucose into our blood, the glucose level rises, the islet cells release more insulin and the cells take up more glucose. It’s a good system, and usually it works brilliantly.

Incidentally, glucagon, which I mentioned before, is in a way the opposite of insulin. It is released in response to lower blood sugar, and stimulates the release of glucose from storage or the creation of new glucose by the liver. These two hormones—insulin and glucagon—in a healthy person, work beautifully in counterpoint, and maintain the blood sugar between roughly 60 and 100 milligrams per deciliter at all times. It’s a lot like the cruise control on a car, which applies a little more or less power as needed to keep the speed where you set it. A healthy body has a very tight and responsive glucose cruise control.

Diabetes happens when the insulin system breaks down. There are two main ways that this happens, and there are, therefore two main kinds of Diabetes…very cleverly called Type 1 Diabetes and Type 2 Diabetes.

In Type 1 Diabetes, there is a failure of the beta cells in the Islets of Langerhans…usually caused by some kind of inflammation destroying those cells. When this happens, there is no longer any production of insulin to speak of, and without insulin, the cells of the body don’t take up blood sugar. Without blood sugar, many of the cells of the body cannot get new energy, except by very specialized and limited means that have their own downside to the body when they operate without restraint. A person with Type 1 Diabetes absolutely requires the administration of insulin from an external source. This is usually done by injection into the subcutaneous tissue by a fine needle, generally a number of times a day. Without this treatment, a person with Type 1 Diabetes will not be able to get glucose into their cells. They will lose oodles of glucose in their urine, they will rapidly lose weight and dehydrate (because all that spilled glucose in the urine carries a LOT of water with it), and ultimately they will go into a catastrophic state called “Diabetic ketoacidosis.” I won’t get into the specifics of this right now, but it DOES involve the blood becoming quite a bit too acidic, among other things. None of the effects involved are good for the function of a human body, and unless treated quickly and given replacement insulin, a person in Diabetic ketoacidosis will die.

Wow, that’s pretty scary, isn’t it? Fortunately, nowadays we have a number of different forms of readily available and inexpensive injectable insulin for Type 1 diabetics to use…and there are scientists working all the time on better ways of treating this disorder, including working on developing insulin that can be given without injection and transplantable replacement islet cells. Stem cell research may be able to deliver that last modality in readily workable form, without the worry about tissue rejection, so we should all do everything we can to support such research.

Well, this has already gotten pretty long, so that’s going to be it for the first half of the article. I’m going to continue this discussion, of course, in Part 2 which will, appropriately, start with the subject of Type 2 Diabetes Mellitus.

So What Is All This GeV Stuff, Anyway?

[This is a reprint of an article I wrote for my hubpage…but I want to focus here on my own page, now, so hopefully no one will be too upset by the re-use.]

Recent news about events at the Large Hadron Collider in Switzerland has brought particle physics more into the mainstream, as scientists have discussed hints that they’re getting closer to finding and defining the Higgs particle…the messenger particle of the Higgs field.

I’m not going to try to rehash the meaning and nature of the Higgs field here. Most of the articles I’ve looked at do at least a decent job with that subject. If you want an even better treatment–as well as a fantastic summary of the state of modern physics that is thorough but extremely understandable–I recommend getting a copy of “The Fabric of the Cosmos” by Brian Greene. He does a better job of explaining difficult subjects in easy-to-understand terms (that nevertheless don’t dumb down the material) than just about anyone else I’ve ever read.

No, what I’m going to talk about is a term that’s thrown around an awful lot in articles about particles: The GeV (and more generally, the eV). The term eV is shorthand for “electron volt,” and “GeV” is the notation for “giga-electron volt”…a billion electron volts, in other words (MeV, mega-electron volt would be a million electron volts).

But wait…the articles about the Higgs (and other writings about atom smashers) refer to measures such as 125GeV as being a measure of a particle’s mass! What does that have to do with volts!? Don’t volts have something to do with electricity? Isn’t household current measured in volts? Does that mean that it takes a Billion times as much voltage as in household current to find a Higgs particle?

Well…not exactly. In physics, the electron-volt is actually a measure of energy, not the voltage in a circuit. Specifically, it’s the amount of kinetic energy (the energy of motion) a free electron would accumulate after being accelerated through a potential difference of one volt. You see, voltage is to electrical fields a lot like what pressure is to water. Voltage differences push things that respond to electric fields…and electrons are one of the most well-known of things that respond to electrical fields, and have been since at least Benjamin Franklin’s time. In other words, falling through a “pressure” difference of one volt will accelerate an electron until it has a kinetic energy that is defined as one electron-volt.

So what the heck does the kinetic energy of an electron have to do with the mass of a Higgs particle? Well, as you probably know, energy can change its form, but it doesn’t disappear, and if need be can always be measured in the same units. At every day energy levels, physicists are more likely to use joules as a measure of energy…a joule is the amount of energy put out by something that has one watt of power in one second. So a one hundred watt bulb puts out 100 joules of energy every second.

Now, when you’re dealing with smaller scale things–like electrons and protons and Higgs particles (Oh my!)–it’s better to use a smaller unit of measure. The eV is a VERY small amount of energy, and can be excellent currency when describing what goes on in interactions between subatomic particles. Just as you wouldn’t use a brick of gold to try to buy a gumball out of the grocery store gum machine, but would instead use your pocket change, you don’t usually use joules in particle physics. You COULD, of course…but you’d be using REALLY small fractions of joules and it’s just easier to use the particle physics version of pocket-change, the electron-volt.

But still, what does this have to do with the mass of a particle? I’ve been talking about energy here!

Well, now we come to probably the most famous equation in all of physics, at least as far as the general public is concerned: E=mc2 (the two here means “squared”, or a number multiplied by itself). This equation explains that matter and energy are interchangeable. Matter and energy are just two forms of the same thing. So you can describe how much Stuff something is made of by describing it in ordinary terms of Mass (such as grams and kilograms), or, if you’re feeling like it and if it’s useful, you can describe it in terms of energy. Now, the “c” in that famous equation is the speed of light, which is mighty fast: about 300,000 kilometers a second (about 186,000 miles per second). It’s already a big number, but when you multiply it by itself, it’s MUCH BIGGER. So even a little mass converts into an awful lot of energy. That’s why nuclear reactions are so powerful: they convert a fraction of a percent of the matter involved in the reaction into energy, and you get all the glory of our sun and all the horror of nuclear weapons.

So finally we arrive at the reason for using eV’s and MeV’s and GeV’s in particle physics. It turns out that, like joules, working with ordinary mass units like grams gets very cumbersome when talking about really tiny things like subatomic particles. You have to use extremely small numbers with a lot of zeroes after the decimal point. If you’d rather not deal with all those zeroes, well, since matter and energy are interchangeable, you can instead describe very small masses in terms of a pretty fair number of a similarly small unit of energy. An electron-volt is just such a useful small unit.

In other words, when they say that the Higgs particle doesn’t look like it can be more than 125 GeV in mass, they mean that, if you took its mass and turned it into free energy, the amount of energy you’d get would not be more than 125 billion electron volts. That may sound like a lot, and on the scale of subatomic particles, it IS. However, it really is a very small amount of energy, and thus an exquisitely small amount of matter.

Of course, the Higgs fields is thought to permeate literally the ENTIRE universe, and the Higgs fields effects are all carried out by Higgs particles, so the mass equivalent of the field would add up to a pretty big amount in total. In fact, ALL the ordinary things with which we are familiar are made up of particles whose masses can be described in terms of electron volts, and most of those “weigh” a lot less than the Higgs appears to. So big things are made up of small things, just lots and lots of them. Like, lots and lots of electron volts of energy can equal the mass of one small but very important particle.