Conservation of Linear and Angular Momentum

September 11, 2017

Some Simple Physics; Conservation of Momentum

There are no strange ideas in this entry. In fact, I might call this a boring entry. If you want to read the weird stuff, read one of my other entries.

I was sitting around reading a primer on particle physics (L.B. Okun) today, and got thinking about the conservation of linear and angular momentum.

Conservation of linear momentum means that, when you chuck something out the rear end of your spaceship, then your spaceship moves the opposite direction, so m1v1 = m2v2 . So, if you toss out a small mass of propellant from one end at a really high velocity, then you move the much larger mass the opposite direction at a much slower velocity (along with your remaining propellant). This is an exponential relationship, but that’s not what this blog is about today, so you can forget learning about that useful tidbit of knowledge.

Anyway, to increase your velocity, you have to chuck part of your mass in the opposite direction. Pretty basic. If you just move stuff around inside your ship, the ship won’t move at all (except incrementally for the duration that you move around in the ship, but you won’t acquire a continuous velocity). Anyone who’s been on one of those playground spinners and tried to throw your body one way or the other knows how that works. You throw your body forward a foot, and the disk rotates a foot and stops.

So you can’t change the momentum of an object by moving stuff around inside. Not even if you have the rocket inside an enclosed sphere. The sphere won’t move.

I was recently (foolishly) wondering if that was true of angular momentum, too, if you had a rotating planet or moon, is there some way you can get energy out of the rotation by diddling around with the insides, somehow tapping the angular momentum of the planetoid for energy. Ultimately I realized you cannot in a closed system, but it should have been obvious to me all along. However, as with a rocket, you can change the angular momentum by ejecting part of the object. You can even speed up the spin a lot or slow it down.

Satellites do this sort of thing all the time. Usually they have spin they want to get rid of, and they call the technique “momentum dumping”. Two methods known to me involve extending tethers (like ballerina arms) to slow down the satellite’s spin, then releasing the tethers, or spinning up a high-speed gyro in the opposite direction of your spin (potentially dumping the core of the gyro, though I’m not certain any spacecraft does that – usually they use the gyros to turn the spacecraft both ways, hoping the overall effect will cancel out, and when the spin in one direction gets to be too much, they finally use propellant to dump the angular momentum). These are called Control Moment Gyros, or CMGs, and they usually have a minimum of three on board to cover the 3 axes.

Carrying this concept one step further, since you can eject propellant from a ship to make it go faster in a straight line, you can similarly spin up a chunk of mass from your planetoid in the opposite direction of your planetoid’s spin to make the planetoid spin faster, then eject that spinning mass into space. What amused me about the idea is that it’s essentially the same as a rocket ejecting propellant linearly to increase linear momentum, but here you are ejecting an object with accelerated angular momentum to increase the angular momentum of your planetoid. The difference being, you don’t ever have to eject the mass; it’s rotating in place, like a CMG.

That’s it. Not really that interesting, I guess. The equivalency of the two systems and the idea of “rotational rocketry” just struck me as amusing.

Trying to Accelerate an Infinite Mass

August 29, 2017

Short entry today; an easily digestible bit of physics.

A number of times in physics books and articles, I’ve come across people stating that “as an object approaches the speed of light, its relativistic mass increases, so it’s harder and harder to accelerate the steadily increasing mass, thus, you can’t speed up.”

I’d like to call bullshit on this argument. As your ship’s mass increases, so does the mass of your propellant in equal parts. If your mass doubles, so does the propellant mass being ejected out of your rockets, and you’re still obeying the law that for every action there’s an opposite and equal reaction. It’s just as easy to accelerate as it was before. You still can’t measurably reach the speed of light, but that’s for another entry I’m working on.

See? Easy peasy.

There’s a more sensible way to get the same results. For the outside observer watching the accelerating spacecraft, as it approaches relativistic speeds, time appears to slow down. For the guy ON the spaceship, he/she has the same amount of propellant per second going out his exhaust as before. For the outside observer, since the spaceship’s time is slowed down, the observer sees less propellant-per-second being used by the ship. As the ship gets closer and closer to the speed of light, it’s using less and less propellant. It accelerates slower and slower. It can never reach light speed.

To the person on the ship, his acceleration is the same as always; if he felt 1 gee at the start of the journey, he still feels 1 gee in his reference frame.

Background Gravity – Time Dilation in a Flat Field

August 11, 2017

I got into an argument with a physics buddy not that long ago (a year, maybe), about gravity. We have an intermittent arrangement where we go drink beer and talk about physics at two or three pubs in San Luis Obispo. Usually, the physics becomes a little less coherent as the evening wears on.

One of the discussions centered on whether there is a “background field” of gravity or not, or whether it’s even sensible to discuss such a thing since, in an infinite field of equally distributed mass (or gas, or 1 atom per cubic light year, whatever), all the forces around you seem to cancel out. The mass of the universe to your left is equal in size to the mass of the universe on your right; you feel a net acceleration of zero. I argued that even though the field was “flat”, there was still a field there. He argued that a field implied a gradient; there is always a force.

We did not come to a satisfactory conclusion. It might merely have been the fact that we were defining the same terms in different ways in our heads. I’m not sure. I thought my argument was rock-solid.

So, here is my side of it.

Some of you are probably familiar with Newton’s Shell Theorem. It’s in his Principia Mathematica, and if I remember right, he solved it without using calculus. Basically, what it says is this; if you are inside a spherically symmetric shell of mass, then you feel no gravity pulling you any direction. It’s a bit non-intuitive. Let’s say the Earth is hollow, and the entire planet’s mass has been compressed into a thin spherical shell a few centimeters (or meters, it doesn’t matter) thick. If you are floating around in your Nike Space Suit inside this shell, you will not be pulled toward the center, or the inner surface of the shell, or anywhere else inside the shell. Wherever you are put, you will remain.

Personally, I think this is one of the coolest theorems ever.

It’s also true that if you are outside the surface of a spherically symmetric planet, then it doesn’t matter how dense it is, at a given radius you will feel the pull of a certain amount of gravity. If you are in orbit above the Earth, and the Earth suddenly becomes a black hole of the exact same mass, you will remain in orbit, totally unaffected by that change. That’s pretty cool, too. Given that the gravitational force is based on F=GMm/r2, this should be kind of obvious. Neither your mass (m) or the mass of the Earth (M) has changed, your orbital radius is the same, and G is the gravitational constant. Ergo, the density of the object you are orbiting at a radius “r” from the center of the object is irrelevant.

So, that was me drifting from the actual subject. Shell Theorem—let’s get back to that.

As you might know, the clock of anyone in a gravity field runs slower than that of a clock outside of that gravity field. This is called gravitational time dilation (and is equal to ∆t’ = ∆t √(1-2MG/rc2) for a non-rotating sphere). A person on Earth actually ages slower than a person in deep space, according to relativity. This was verified with clocks flying around the Earth in the Hafele-Keating experiment. Before you ask, yes, they took into account Earth’s rotational speed, the speed of the airplane (in both directions relative to Earth’s rotation) with regard to Special Relativity’s time dilation due to velocity. It was a nice experiment.

Let’s say we’re using a hollow Earth from Newton’s shell theorem. As you get closer to the Earth, you are in a deeper gravity well, and the outside observer sees your clock slow down. There’s a small hole in the planet, and you pass into the planet, where everything is pulling you in opposite directions equally, so you seem to feel no force. And yet, your time dilation effect does not suffer a discontinuity, jumping suddenly to that of the outside observer. You are in a denser gravity field, but a flat gravity field. [to the physics majors out there, for god’s sake, if my terminology sucks, please correct me]. Your time dilation will be just the same as if you were standing on the surface of the planet.

So now you have a flat gravitational field (no “force” pulling you in one direction, that is, all forces pulling you equally in all directions). And yet, even in this apparent lack of gravity, where you can’t actually tell that you’re in a gravity well, your time runs slower than the time of someone far from the planet.

I extended this argument to the rest of the universe. If mass was distributed equally around you, even though you felt no force one way or the other, there would still be a background gravitational field. Gravitational time dilation implies a gradient; for time dilation to be relevant, you need someone in a weaker gravitational field measuring your time. However, both the measured and the measurer can be in locally flat gravitational fields.

Does a flat gravitational field curve spacetime by itself? Or is it only the gradient between two different gravitational fields that curves spacetime? My general opinion is that you don’t need the gradient for the curvature of spacetime. If you have an infinite universe with equally distributed mass, then from some arbitrary center, it will appear to curve spacetime until it closes the dimensions of universe into closed loops, like the inside surface of an event horizon (though other arbitrary centers will have different, yet overlapping event horizons – a subject I will touch upon another day). Likewise, if you have a large, thin flat sheet of soapy water in the air, fluctuations are going to cause it to form bubbles, closing up the edges. In spacetime, there may be a similar tension (gravity?) that closes the edges together into a 4D hypersphere.

How would you test the curvature of space inside a shell? I’m not entirely sure. I think the universe we have is a good test case, however.

Particle Pair Production in Deep Space

August 6, 2017

Many of you know that a matter-antimatter reaction results in a pair of gamma rays. Fewer of you will know that you can take a couple of gamma rays, run them into each other, and get a pair of matter-antimatter particles. This has been done experimentally, and there’s a bit of data about it under “Two Photon Physics” in Wikipedia. Generally, if a subatomic reaction can occur, then it’s reversible. Maybe not statistically probable, but still reversible. This is a concept I used in a story I recently sold to Analog SF. In an area of space with high-density, high energy gamma rays, you’ll get a lot of positrons and anti-protons produced (more positrons, since they are 1/2000th the mass, of course), but there will also be some small production of antihydrogen if the antimatter doesn’t recombine right away with normal matter. And the antihydrogen may be neutral enough to survive and drift in deep space for a while, maybe long enough to be used as a resource.

Some reactions result in the release of more than two photons. A particle and antiparticle meet, three photons are emitted. The photons are lower energy, but the reverse reaction, 3 photons meeting, is a much, much lower probability than 2 photons (gamma rays) meeting. Still, on rare occasions, it might happen.

In fact, it’s my belief that if you have enough photons, even low-energy photons, passing through the same bit of space at the same time, you can also have pair-production, spitting out particles and antiparticles. One calculation for photons from the cosmic microwave background radiation (CMB) estimates 400 photons per cubic centimeter, average, plus whatever higher-energy visible light and gamma rays pass through from billions of stars. And there are a lot of cubic centimeters in a light-year (about 4.9 x 1050). Even if the probability of pair production is very, very low, I still imagine that it would happen on occasion.

As a side-note, the probability of a positron and electron meeting in deep space is very high, since they attract one another, while the probability of two gamma rays meeting at just the right time in just the right way is fairly low. The reaction looks symmetric, but the probability of it happening in a certain direction is much higher one way than the other. Ditto for any two-particle reaction that creates three particles. This contributes to the increased entropy of the universe and the “arrow of time”; there’s a preferred direction for these subatomic reactions to occur.

Looking All the Way Back in Time

July 31, 2017

If you look back in time, (up in the night sky, at the light emitted from galaxies billions of years ago), you are actually looking at an earlier version of the universe when it was smaller.

images-3

Due to the nature of how light moves through space, when you look back 14 billion years to the farthest reaches of the universe, you are actually looking at a very small volume. But the image, warped as it is, is spread out and fills the farthest regions of the sky, like a view through a concave lens. If you were able to look all the way back to the tiny point of the Big Bang, the image would be smeared and spread out across the 14 billion light-year shell, any detail of the event washed out by turning the fine detail of a tiny event into a picture the size of the universe.

So, when you look up at the night sky, everywhere you look in the blackness of deep space, 14 billion light years away, is actually the same small point.

Does this make sense? I’m trying to think of a good analogy for this, but it just isn’t coming to me. Maybe like starting with a tiny drawing on the surface of a tiny sheet of rubber, then stretching it out so that the sheet of rubber stretches all around you in a sphere, like the inside of a balloon, and then trying to figure out what the original picture looked like.

This, of course, begs the question of what physicists are calculating when they measure the accelerating expansion of the universe. If the universe was physically smaller 14 billion years ago, and now the remaining image of it is spread out over a sphere with a radius of 14 billion light years, that’s going to come off as an acceleration; the farther you look, the smaller the original volume and the more the image is spread out over the apparent warped view of the current volume. And, of course, 14 billion years ago, the universe actually was expanding a lot faster than it is now. It’s a double-whammy of accelerations. Most physicists are a hell of a lot smarter than me, so I’m guessing that both these accelerations have been calculated into the “accelerating expansion of the universe” equation. I can only speculate that there is a third element. I wish I could find out without wading through a lot of really obscure math.

Photons Dancing on the Head of a Match

May 1, 2014

Who cares about angels on the end of a pin? Let’s get real; how many photons are there on the end of a match?

There’s a lot of data out there to help us calculate this; one article says that the human eye can detect a candle in the dark at 30 miles. Isn’t that something? The same article says it takes at least 54 photons just for the human eye to register an event. So that match (or candle) has to get 54 photons into that fraction of your eye that actually receives and focuses the photons. But the whole eye doesn’t actually receive the photons; it’s just the black opening in the middle. The largest it ever gets is about 7 millimeters diameter, which is 38.5 square millimeters in area, or .385 square centimeters.

How many events can the human eye see in one second? If we’re looking at the match from 30 miles away, and it looks continuous, then we are receiving over 50 frames a second (though the human eye has been recorded as being able to discern and identify an image in 1/255th of a second, we’ll be conservative). If the image were less than 50 times per second, we would detect a choppiness in the image; still, overlap in the match’s photon emissions could turn a choppy image into a smooth one. But lets assume we get a continuous 54 photons, all the time, at least 50 times a second; anything less would look like a flicker off.

Now we have everything we need to calculate how many photons are coming off the head of a match!

Just put an eyeball…or just the iris, the bit that receives the light, in every spot in a 30 mile radius, add up the total number of irises, multiply by the 50 times-per-second, times the 54 photons per eyeball, and we should have the number we need.

The sphere of irises is 4*pi*r-squared. Or 4*3.14*30*30 = 11,310 square miles, or 29,292 square kilometers. Or 29,292,000,000 square meters. Or 292,920,000,000,000 square centimeters. Since each dissected eyeball (just the iris, you see) only takes up .385 square centimeters, that’s about 760,000,000,000,000 irises stuffed carefully into the perimeter of the sphere to capture all the photons.  Just as a point of interest, that’s about 50,000 times the number of human eyeballs on Earth. Guess we’ll be dissecting all the other animals, too. May as well start with fisheyes; they’re sort of gross to begin with.

Each of those eyes is gathering 54 photons at least 50 times a second, so we get to multiply the 760 million million by another 250-ish, giving us a grand total of about 190,000 million million photons off the head of a match every second. Or, just because I like a lot of zeros, 190,000,000,000,000,000 photons. Every second. From a freakin’ MATCH HEAD. We are awash in a photon bath.

Now, leave the darkness of night, and realize that when you walk outside, you are no longer looking at one tiny spot radiating onto 190 quadrillion eyes, now you have a hemisphere of 30 cubic miles of daylight radiating onto your eyeball. Well, okay, you can’t look at the hemisphere all at the same time. Your turn to do the math! How many photons are hitting your eye every second? Hint; it’s an absolute crapload of photons.

We Are The Meteor

July 20, 2013

Not that long ago I was reading an article by Robert Zubrin, called “Carbon Emissions are Good“, where he stated an oft-repeated mantra by those who think global warming, while real, is no big deal.

It generally goes like this; “Global Warming cycles have occurred in the past, life has dealt with it, and in some cases, done even better than now due to all the extra CO2 in the atmosphere.” Zubrin writes, “while it is entirely possible that the earth may be warming — as it has done so many times in the past — there is no rational basis whatsoever to support the contention that carbon-dioxide-driven global warming would be on the whole harmful to life and civilization. Quite the contrary: All available evidence supports the contention that human CO2 emissions offer great benefits to the earth’s community of life.”

Sorry, but this is a completely false statement, and apparently Zubrin neglected to read much of the “all available evidence” he mentions. It completely ignores one of the major components to the problem. As Brian Huntley puts it, “The rate of climate change forecast for the future is 10–100 times faster than the rate of deglacial warming.” His paper, “How Plants Respond to Climate Change: Migration Rates, Individualism and the Consequences for Plant Communities” in Annals of Botany talks about the critical issue; how fast plants and animals can migrate when an environment changes too much to support the plant life.

Herbivores can’t live without the plants they eat. Plants can’t migrate themselves except through a few very slow processes, including undigested seeds, wind distribution, sticky seeds, and water and mud flows. Given a thousand years of slow warming, the natural random distribution of seeds with these mechanisms might allow plant and animal species to spread to local environments that are more habitable. Given a hundred years, the slow random redistribution of seeds means that the old environment will die out before the new one has a chance to migrate or take hold; massive extinctions of the whole food chain will occur. Plants and animals have, indeed, evolved mechanisms to allow migration, but these depend on slow, natural rates of heating and cooling, rates that allow a slow peripheral migration, not the wholesale destruction of one habitat to be replaced by another more suitable 1000 miles away. There are barriers and thermal pinch-points that can prevent a species from migrating at all.

If you were in a room quickly filling with milk, and you had no exits, Dr. Zubrin would point out how healthful the milk is for you.

Rather than the slow process of deglaciation, a climate altering event more comparable to human global warming is a giant meteor strike, resulting in climate change that occurs in weeks and lasts for decades or longer. Sure, this is the other end of the scale, but we also know for a fact that such events are quite capable of wiping out 90% of the extant species. Species have no chance to recover from such an event, or migrate to more pleasant climes.

Unfortunately, we have become the meteor.

Billionaires of Mars

August 10, 2012

If you could write a check for a spaceship to Mars, would you?

That’s exactly the situation we have right now. There are over a hundred people on Earth right now with personal wealth weighing in at over $10 billion dollars. Gates has over $60 billion bucks available. Any one of these people with any interest at all in putting a colony on Mars, basically, owning Mars, could do so within a decade.

Robert Zubrin, an advocate of a unique mission profile, stated in an article, “…while Mars Direct might cost $30 to $50 billion if implemented by NASA, if done by a private outfit spending its own money, the out-of-pocket cost would probably be in the $5 billion range.” Wow. Five billion. And his mission profile advocates bringing people back, unlike the Mars One group from the Netherlands who wants to do a one-way mission to colonize the planet; of course, now you’re paying to take enough food and infrastructure for people to stay there.

The key point of this is that, given the will of one person (one very rich person), we could be standing on Mars in 10 years time. We could be living on Mars. The Mars rover, Curiosity, just did a radiation measurement that indicated levels are “not a showstopper”. About the same as low-Earth-orbit. Woo-hoo!

And most important of all, if this rich person has a brain, they can make money on the effort. Richard Branson ($4 billion) or Elon Musk ($2 billion) seem to already be heading this direction, building the infrastructure to get to space on their own terms and making money at it as they go (via Burt Rutan’s Scaled Composites, Virgin Galactic and SpaceX). The Mars One people talk about turning the mission into a media extravaganza, a reality show to beat all reality shows, an advertising blitz to beat all others. What would Pepsi pay to have their logo on the first manned lander? What would the first returned samples from Mars be worth to collectors? Can you imagine what actual fossils would be worth if they find them?

And you don’t even have to spend a cent developing the rockets to get you into Earth Orbit. Elon Musk has already done the design work; you can launch 10 Falcon Heavies for a billion dollars, delivering a half-million kg of fuel and hardware to low-Earth orbit.

Let’s look at the potential returns on this for a billionaire entrepreneur;

1. It’s been suggested that a $5-10 billion NASA X-Prize be offered for a private manned mission too Mars. Fine, but likely with lots of strings attached. Still, there it is; your entire mission paid for if you’re successful.

2. Advertising. This starts the moment you actually commit to the project. Just the televised weeding-out process for wannabee astronauts could bring in millions of dollars as a reality show. Competition between countries for seats on the rockets, Olympic fervor and excitement. That could last years. Licensing for games, the official mission logo plastered on every product on Earth, books, autographs from the team members, photo ops, speaking gigs (hey, you own those astronauts, part of the contract), product placements, donations for a variety of perks, or just donations…the list just goes on and on. If I were in advertising, I could make back the $5 billion in the 5 years before the first rocket left the launch pad. How many million-dollar stickers could you get on the side of your lander?

3. Building the rocket to get there, assembled in Earth orbit offers more advertising, more excitement, pay-per-view.

4. The trip there, of course, would be televised. Interviews would be sold. Unlike NASA’s model, nothing is free. Perhaps a bit more reality show programming and product placement advertising. Nothing like a Mars bar when you need a break from your EVA, is there?

5. And when you land, what is that worth? Renting out the copyrighted footage from the first manned landing? Aforementioned ad-space on your hardware? Commercial breaks? The knowledge that you’ll be getting royalties off this footage for the lifetime of the copyright? And the check you got from the country (or company, or person) that paid you off so their guy would be the first on Mars?

6. Experiment space could be sold for your arrival on Mars. Personal items or human ashes carried there and buried there. Designer bacteria could be taken along and tested in the Martian environment. Designer plant species, lichen and such, patented and ready for the colonists to spread around. If the colony was set up inside one of the many known lava tubes on the planet (such as those near Pavonis Mons), with solar collectors and solar pipes channeling the light inside, the colony would be surrounded by rock and safe from radiation. Lava tubes could provide huge living quarters with very little preparation.

7. And once you’re settled? Rent out your colonists. Tell us where you want to go, what samples you want collected, where you want that pickaxe swung. We’ll hop on our Martian bicycles and go check it out. Now that you’re there, anything you sell is just a bonus for you. For that matter, rent out little rovers with cameras. Sure, it’ll take 4 to 20 minutes for Earth-commands to go back and forth, but you know folks would rent time on them. Why stop there; super-light-weight flyers can be programmed to see all sorts of interesting things.

8. Property. Oh yeah, barring international agreements which won’t really apply to you since they can’t reach you, you own Mars. You want to buy 20 acres on Mars? We’ll sell it to you with a deed. It might be underwater when Mars starts to warm up, but that’s the risk you take. Lava tubes, now those are premium property! Create your own Government for your colony and claim it all. Work out deals with Earth governments so they don’t try to steal it all back. Better yet, sell them large swaths of Mars.

9. Sell support services for other colonists and countries. Once you prove it can be done, others will follow, and you can sell some of your infrastructure services (like a communications satellite, if you left one in orbit, you can rent bandwidth. Or a berth in your colony, if the new arrival wants to rent or buy a place to stay). Once they find out you’re trying to claim Mars for yourself, well, there won’t be any lack of newbies clamoring for a piece of the action, and they’ll all be paying you rent for your existing infrastructure.

10. Propellant; assuming you’ve tapped off of some of Zubrin’s brilliant ideas for making propellant from the Martian atmosphere, you can sell that to potential customers. Hey, we have water and propellant for sale! Come as you are. We have the supplies to send you back. For a price.

11. Patents on new minerals, compounds, and materials, and if you’re very, very lucky, microfossils. Unique gemstones on Mars? Who knows. Getting them back to Earth is a problem, but once your infrastructure is in place, heck, that’s a mission you could pay for with pocket change and make your money back ten-fold. Take stamps to Mars and ship them back.

12. And it gets stranger…once your colony is pressurized to 0.5 Earth-atmosphere in 1/3rd G, it’s time to pull out your sports-wings and fly around inside your 200-meter wide lava tube (yeah…they’re huge). You get to start your very own Martian sport. Which team will you bet on? Which Earth-network is going to pay to broadcast it? And Superbowl advertising for $4 million dollars per ad? You ain’t seen nothin’ yet.

Okay, sure I forgot some things. Let me know. Point is, we can go to Mars now; all we need is a billionaire with a dream and a marketing team that makes sure he remains a billionaire. After all, you’ll want to have money left over for that next colony.

UPDATE: Elon Musk (the Paypal billionaire) spoke at the Mars Society Convention in Pasadena last week, and expressed his interest in colonizing Mars, and making seats available for $500,000 a head for would-be colonists. Go, Elon! I might be too old to make the trip by the time this happens (being a spry 58 now), but at least I can make the trip vicariously! If you want to have your spirits bolstered by what he says, you can watch it here. Skip the Zubrin introduction – it’s lengthy.

God vs Evolution; Inherited Gene Mutations

November 21, 2010

The key to exposing those processes of evolution that appear completely nonsensical if attributed to an intelligent designer is to ask these two questions;

1. If God designed this, what would he likely have done? And
2. If the process of evolution produced this, what would be the end result?

A great example of this is the case of every living thing eating every other living thing just to survive. If I assume as a basic foundation that God is a loving, caring individual and really likes humans more than anything else, then one would have to guess that he would not design an entire ecosystem where the primary goal of each member of that system is to kill and eat one of the others. Humans are just “food” to a number of viruses, bacteria, parasites, scavengers, and large predators. While this appears to be a perfect characteristic for an evolutionary process of competitive consumption and mutation, it’s entirely moronic from the perspective of any sort of intelligent design. Add to this the fact that some vegetarian humans choose to avoid killing any other animals and it tells us that it is, in fact, possible to have an ecosystem where nothing kills anything. God was just too stupid to figure it out. There are quite literally thousands of species of scavengers and insects and plants that eat nothing but already-dead organics. Wouldn’t that be something; an ecosystem where animals would only eat each other after they died from other causes?

Of course, an evolutionist would argue that this could not stand; eventually one animal would evolve the brilliant trait of killing other animals to assure their timely death, drag the carcass off, and nibble on it only after it had decomposed to an edible state, like a pheasant hanging in front of a British butcher’s shop. Killing to eat, as you can see, is an inevitable state of evolution, not the hand of intelligent design. But this, again, assumes that an animal could naturally evolve at all without God’s thick fingers in the dough. Even if God had started with such a benevolent, non-violent system, mutation and evolution would inevitably have driven us in the direction that it has.

So, again, look at the questions; How would God design something, and how would evolution mould it?

Take genetics. There’s the obvious fact that every living thing, even viruses, use DNA, and use the same code sequences that all the other organisms do. The gene that makes haemoglobin in humans is very much like the gene that makes haemoglobin in pigs, and in fact can and has been spliced into pig DNA so that the pig had both human and pig haemoglobin coursing through its veins. The genes are just little strings of codes, and the fact that genes that do the same thing in each animal tend to be nearly identical should be a pretty obvious clue that evolution, with its accumulation of mutations, has been at work. However, the ID proponents will tell you that God has merely taken a good design and used it elsewhere, tweaking it for that particular organism.

So the ID argument is founded on the idea that God can apparently pick and choose what genes he wants to use in each animal. After all, he designed them, right? We might expect each animal to have its own unique genes, with common functions duplicated in between species as very similar genes.

But here’s the problem. If there are 5 genes in a Human, let’s just call them A, B, C, D, and E, and we compare them to their functionally equivalent genes in a muskrat, we would expect some variation between each pair of common genes in the two animals. If God can just pick and choose genes and tweak them to his heart’s content, we would expect the Human-A gene to be different from the Muskrat-A gene by some percentage, like 5%. Evolutionists would consider this 5% as an accumulation of mutations after splitting from a common ancestor. The B-gene might be 20% different, and the C-gene 50% different. And so on. God can pull genes from anywhere and do anything he wants with them. So any level of variance between two genes between two animals would be possible, right?

Wrong.

What we find is the answer to “what would evolution do?” question. If two animals descend from a common ancestor (well…they ALL do), then we would expect a certain mutation rate to occur in the genes of the each animal, a “molecular clock”. All the genes in the animal would maintain this same rate of mutation accumulation, being exposed to the same mutating environment, the same statistical distribution of unexpected change. What we would expect is that the 5 genes between human and muskrat would have roughly the same percentage difference for each pair of common genes.

This, not surprisingly, was the result of an experiment done by David Penny and published in 1985, using 5 genes which were so similar between species that they have the same name in each species (the experiment is described by Richard Dawkins in The Greatest Show on Earth, page 322). Except they checked the 5 genes across a group of 11 mammals. The results were as mentioned above; for a given pair of animals, the number of mutations in similar pairs of genes were consistently close to the same percentage across all 5 pairs of genes. Other experiments since then have expanded on Penny’s work, with similar results. Incontrovertibly, it points to the FACT that each pair of animals had a common ancestor and accumulated a statistical average of mutations since the speciation event occurred.

What it does NOT show is that God picked whatever gene he felt would help the animal survive best and slap it into the animal’s DNA matrix. This would have given totally different results, with a broad variance of mutations between pairs of similar genes.

This experiment, above and beyond any other experiment I’ve read about, proves beyond a doubt that ID is bogus, and evolution suitably describes exactly what we would expect. There is no intelligent designer picking and choosing; there is only a random, statistically averaged accumulation of mutations weeded out by competition and speciation events.

If this isn’t enough of a nail-in-the-cofffin for doubters, there is the issue of viral scarring in human DNA, which not only hammers in the last nail, but buries the coffin besides. Retroviruses have a nasty habit of inserting their own code into the human DNA sequence. Estimates are that 8% of human DNA (of the 95% that’s considered “junk DNA”) is viral in nature, inserted in the past by retroviruses. This portion of our DNA is, in essence, a fossil record of every virus that humans and their animal ancestors have had to fight during their long history.

It should be pretty clear even to ID proponents that God wouldn’t go out of his way to add inert viral sequences into our own DNA. However, just the fact of its existence is not the telling point (although it isn’t a bad point by itself).

Viral scarring in DNA shows up in the same place in the gene sequence in different creatures with whom we share a common ancestor. Apes and humans, humans and rats, if you look, you find that both species carry the signature of ancient viral attacks that left a physical scar behind, inserted in exactly the same place in the equivalent gene in both animals, a viral attack that occurred before the two species went their separate genetic ways from their common ancestor. Here you have two different animals that both just happen to have the same viral-scar in the same place in the equivalent gene in both their DNA sequences; only an evolutionary process can explain this.

The fabrication and rationalization of an ID proponent could only stretch so far before it shatters into nonsensical fragments while attempting to explain these evolutionary results. The fact of evolution is sealed in genetic documentation, a book merely waiting to be opened and translated into the history it provides.

Are There Two (or more) Living Species of Humans?

November 9, 2010

For those of you looking for some racist rant, you’re not going to find it here, despite the interesting title.

Here’s the conjecture; there’s a lot of genetic diversity in humans. Is there enough variation between humans to prevent two of them from producing fertile offspring, and if so, could they be considered two different species of humans?

Amongst the seven species in the genus Equus, we know that horses and donkeys can breed together, but always create sterile offspring (mules, that is). Likewise, zebras and donkeys have produced the “zeedonk”, which is also sterile. The definition of a species separation is that two animals from separate species cannot produce fertile offspring. Sterile mules and zeedonks, fine, but you won’t be seeing a purebred line of mules any time soon.

So theory has it that speciation occurs when two groups from one species are separated for so long that accumulated mutations in their DNA prevent them from making babies effectively, or making effective babies. It’s actually senseless to speak of two species that can crossbreed, because then, of course, by definition they are the same species.

But here is where it gets interesting. Let’s break a species up into tribes, or herds, whatever. What if tribe A can breed with tribe B, and tribe B can breed with tribe C, and C with D, and D with E. But they are spread across the country, and though there’s been some local mixing, tribe A is so genetically different from E that they can’t breed at all. Are they then different species? If a meteor came along and wiped out B, C, and D, then there would be no doubt at all that A and E were now different species. And yet, if you plopped all these tribes into a city, you would only have a statistic for “infertility” between certain members that appeared to be unable to produce fertile kids; the Zeedonks of the human species, the chance meeting of a type A and type E person.

So it’s entirely conceivable that all humans could mate with 99% of all other humans, but would qualify as a “different species” when paired up with any member of the other 1%. Thus, though the species superficially looks like a single species, you could selectively sample two humans and technically prove they are different species, even though each of them could produce viable offspring with a large and overlapping majority of other humans. Wouldn’t that be odd?

It would be interesting and informative to take a broad sampling of genes from both parents of sterile children and see if, statistically, they have a much broader genetic difference than parents of non-sterile kids. It would also be telling to know if children from mixed marriages (racial, not religious!) tend to have a higher incident of sterile offspring. And lastly, if any of this is correct at all, I would expect that the percentage of sterile offspring would be on the rise, because the world has lost its tribal nature and interracial marriages are much more common than they used to be. This should be a fairly easy statistic to locate and correlate with the evolution of travel in the world, with isolationist communities like China offering a valuable “control experiment”.

A problem with this list of data-mining “experiments” is that our society tends to associate sterility with an individual, not with his or her parents. We need to establish a data-base of genetic information that goes back a generation from the sterile individual, not assume that the cause of the problem started with him.

Of greater significance and concern is that our rush toward universal mixing, though perhaps ethically desirable, could result in such an incredible diversity of genetic mixing due to the huge population involved that the norm might become sterility. There may be a maximum population-mixing size allowable before it self-sterilizes, and forces itself into a mass speciation event. Or it could mean the opposite, and human blending will become so complete that there could never be a human Zeedonk. It’s hard to say; the rules of human society have had such a non-natural effect on the rules of evolution that they hardly apply to us anymore, despite the fact that we continue to mutate and evolve, or devolve as medical advances help keep us alive. However, I find the questions that I’ve proposed of weighty enough substance that, hopefully, someone with more intelligence and energy than myself may decide to pursue them to their natural solutions.