See It to Believe It

We've all heard that the universe is expanding, right?  But what does that really mean?

A common model for understanding universal expansion is the dough model.  Imagine a lump of dough with raisins in it.  All of the raisins are stationary in the dough, but as the dough rises and expands all of the raisins move apart from each other.  Two raisins that are really close to each other wouldn't be moving apart very fast, but two raisins at opposite ends of the loaf would be moving apart at a much higher rate.

Now when we think about the universe, it's more than just the distance between objects (the raisins) that's increasing, the fabric of "space-time" itself - the dough - is expanding.  Matter can't move faster than the speed of light, right?  But that's in relation to the space-time it's in, not to us.

As we look further and further away into space, space time is moving faster and faster away from us.  Eventually, you get to a point where space time is moving away from us at light speed.  This is called the event horizon.  You can think of it as the "point of no return" because anything beyond that point is moving away from us faster than the speed of light, and so is lost to us forever.  If someone on a planet beyond the event horizon shone a laser at us, that laser light would never reach us ever!  Since space-time is moving away faster than light-speed, the laser (traveling at light speed), even thought it was pointed at us, would be moving away from us. A similar phenomenon occurs around black holes - that's why nothing that goes in ever gets out.

In other words, anything that is beyond the event horizon or that crosses the event horizon is lost to us - forever.  It becomes undetectable.  As far as we're concerned, it may as well not exist, right?  But it does exist!  We know it!  We just can't prove it.  Or provide any evidence of it.

So how do we know that there are things out there that we can't observe?  I guess we'll just have to take it on faith.

The Perfect Code

We've created some pretty clever ways to store things.  Let's consider information storage.  It's not uncommon to see hard drives that can store a terabyte or more.  A terabyte is over 1 TRILLION bytes.  And we can fit that all into a drive that fits in the palm of your hand.  So does that mean that we are efficient at storing information?  Well, let's compare it to a form of information storage that is already in the palm of your hand - over 3 billion times.

DNA is an incredible form of information storage.  A long chain of molecular "bytes" that fits inside of the nucleus of a microscopic cell.  It stores enough information to make an entire human being - every mark and feature; every cell on and in your body as well as every facet of your mind, intelligence, and personality.  A human being is incomprehensibly complex.  And yet the information to make one is stored in a structure so small we need an atomic-force microscope to view it in detail.  But even more than its small size, what is really astounding about DNA is its efficiency.

Human DNA has about 3 billion base pairs.  There are four possible base pair combinations.  We need two bits to get four different possible combinations, so 1 base pair = 2 bits.  Hence, one byte (8 bits) is equal to four base pairs.  So if we do the math, human DNA with its 3 billion base pairs would have
3,000,000,000 base pairs / 4 base pairs per byte = 750,000,000 bytes.

750 million bytes is equal to 0.698 gigabytes, or only .000682 terabytes.  So you could fit all the genetic code of 1.5 thousand different people onto your 1T hard drive!

Compare that to storing movies on your hard drive.  A two-hour movie is about 5.33 gigabytes.  So on your 1T hard drive you could store a mere 187 movies.  If you thought that our man-made information storage is efficient, think again.  Human engineering makes movies that are 10 times bigger than your entire genome - talk about inefficient!

Seeing how impossibly perfect our genetic code is makes me wonder why our man-made encoding is so inefficient. It would seem that as good as our best programmers and engineers are, they're still not the best out there.

Building Blocks

There are over 12,000 (and counting) different LEGO bricks out there.  That allows for quite a bit of building variety.  However, what's really mind-staggering to me is the diversity of things made from a different set of building blocks.  This set includes 91 different pieces ranging from Hydrogen to Uranium.

Now you may say, "Wait, there are 118 elements, and Uranium isn't number 91."  Well, for now I'm only considering naturally occurring elements.  And as long as we're throwing out man-made elements, we may as well focus on just a couple of specific elements.  Let's take a look at carbon, hydrogen, and oxygen.

74% of our galaxy is composed of hydrogen.  1% is oxygen, and 0.5% is carbon.  (24% is helium, and the other 0.5% is all the other elements.)  So helium aside, our galaxy is built mainly of three building blocks.  So what exactly can you make from these three things?  Just about everything.

Take you, for example.  Your body is composed of 65% oxygen, 18% carbon, and 10% hydrogen.  (The rest of you is very small amounts of N, Ca, and K, with trace amounts of other elements.)

This, of course, all comes from what we eat.  Starches, sugars, fats, carbohydrates, lipids, vitamins, oils - they're all made out of nothing but carbon, hydrogen, and oxygen.  Even many of the flavors we enjoy are made of these three elements.  Vanilla flavoring is C₈H₈O₃.  Cinnamon is C₉H₈O.  Pears, bananas, oranges, pineapples, and apricots - they're all a chain of carbon atoms with two oxygens and a bunch of hydrogens.  They differ only in how long the carbon chain is.  Spearmint (C₁₀H₁₄O) is the mirror image of the molecule responsible for rye flavoring.

Carbon, oxygen, and hydrogen seem innocent enough, right?  We eat them, we breathe them, we ARE them.  However, assembled correctly, they could be quite dangerous.  You wouldn't want to drink, for example, hydrogen peroxide.  H₂O₂ is just water with an extra oxygen, but it's highly toxic.  Xylene, a ring of carbons with two oxygens tagged on, will corrode just about any non-polar compound.  Alcohols, fossil fuels, solvents - all are made of C, H, and O.  Throw in a couple of nitrogen atoms and you can make dynamite, plastic explosives, and nitroglycerin.

Most of our clothes are made from either cotton or polyester.  Cotton is made of cellulose, which is a chain of glucose molecules, which is made of carbon, oxygen, and hydrogen.  Polyester, polypropylene, polyethylene, and polystyrene make up clothing, milk jugs, trash bags, pop bottles, styrofoam, carpet, and much more.  And, of course, all of it is nothing but carbon, oxygen, and hydrogen.

We've barely even scratched the surface of what you can make with these three elements.  Don't even get me started on the composition of stars, and nebulas.  The point is, the universe is amazing.  The fact that things work out so perfectly is incredible.  "Coincidence" is pretty great, huh?

Nuclear Power - Part 3

The U.S. energy economy is heavily fueled by coal, petroleum, and other fossil fuels (coal accounts for well over two times more than anything else.)  So why break tradition and start going nuclear?  What are the advantages? Well, there are several.  To list just a few:
1. It's Healthier.
2. It's safer.
3. It's "greener".
4. It's much cheaper.

It's Cleaner and Healthier - It's no secret that the burning of fossil fuels creates  pollution--and lots of it.  Burning coal is the number one source of mercury in our environment today.  In addition, coal-based energy production is one of our largest contributors to greenhouse gases.

It's Safer - According to the International Energy Agency's study Environmental and Health Impacts of Electricity Generation, from 1969-1992, in the coal power plants studied there were a total of 3,600 accident fatalities, not including post-traumatic casualties and severe injuries.  This averages out to be about one death for each 3 GWa of energy produced - a rate 4-thousand times greater than that for nuclear energy production.  Not to mention the deaths and illnesses caused by coal-burning pollutants.

It's "Greener" - There are two possible sources of environmental risk to take into account when considering nuclear power.  The first is that nuclear power is harvested by heating up water.  If dumped straight back into the river or lake it came from, the temperature change will affect the water's capacity to hold oxygen, and therefore fewer fish will be able to thrive in that water.  The solution is to cool down the water before returning it to the environment.  When you think about nuclear power, you may envision those hour-glass shaped towers with steam billowing out the top.  Those are simply water-cooling towers.  Nothing more.  The second risk to consider is the risk of radioactive waste leaking into the environment.  The solutions here are many.  First on my list would be re-using the radioactive isotopes still left over.  "Spent" fuel rods still have usable fuel in them (why do you think they're still radioactive), so why not use it?  Second, new storage techniques minimize the risk.  We can now turn these wastes into a durable glass, which certainly won't be "leaking" anything.  When compared to more traditional energy production methods, nuclear power is by far better for the environment.

It's Much Cheaper - When considering how much we use, coal is very expensive.  The US alone spends around $500 billion on coal every year.  We don't produce near enough to be energy self-sufficient.  However, we have in the US right now, enough Uranium-235 to be energy self-sufficient for a full century.  Apart from that, Uranium is still cheaper than coal.  1 kilogram of U-235 costs about $2.5 thousand to purify and enrich.  That much Uranium will produce 360,000 kWh, or in other words, about 77 cents per kWh, whereas coal costs $50 to $70 per kWh.

All in all, nuclear energy is the smart way to go.  So why don't we go nuclear?  For starters, the media hypes it up so that the public is afraid of it.  If somebody dies in a nuclear accident, the whole country hears about it (note that the US hasn't had a single death in nuclear power generation for 25 years).  On the other hand, people die producing fossil-fuel based energy every day, but we don't hear about those accidents.  So let's start by being informed.  I hope I've given you an idea about how it all works.  That way, when it comes to voting on these decisions, you'll be able to make an informed decision.  It's time to start considering these issues, and it's time to start taking action.

Nuclear Power - Part 2

So why is it that everyone is so afraid of radioactivity?  Is it really that harmful? What's the risk?

Well the short answer is that at high levels, yes, radioactivity can be harmful. The reason behind that is this - when a nucleus decays (breaks apart), it splits into two smaller atoms and can also shoot out other small particles such as electrons, neutrons, and photons (called gamma particles in this case). These particles can be absorbed into other atoms, causing some change in that atom.

So the thing that makes radiation potentially dangerous is that if a radiation particle were to hit one of the atoms in your DNA, it could change that atom into something else and thus change your DNA. Hence the myth that radiation causes people to grow extra arms and eyes.

Now before everybody panics that their DNA is being mutated, it's important to note that radiation is nothing new to the human body.  There is radioactive carbon in the air, as well as radioactive tritium.  Bananas contain radioactive potassium.  The sun is showering us with nuclear particles, be we under a roof or not.  In fact, you are hit by about 15 THOUSAND radioactive particles every second!

The reason we don't all drop dead is that the chance of one of those particles actually causing damage is minute (your chances of winning the big jackpot lottery are literally BILLIONS of times higher than the chance that one of these particles will harm you.)  Not to mention that cells are usually able to fix altered or damaged DNA.

So in short, don't go jump into a nuclear reactor, but if the world's energy starts to go nuclear, don't blow up about it.

Nuclear Power - Part 1

Nuclear power – we all know it's a source of incredible, almost unlimited energy. But it's kind of scary to think about, isn't it? Or is it? Let's take a moment to understand the physics and chemistry behind it before we all run for the bomb shelters.

“Nuclear” refers to the nucleus of an atom – its protons and neutrons. This nucleus is a positively charged ball of tiny particles. Now you know that opposite charges attract, and like charges repel; as in a magnet. So you'd think that magnetic force would just blow all those protons apart – and it would, if there wasn't something else holding them together. There is some energy holding it all together. Where does that energy come from? Well that's where things get a little weird.

Let's look at the nucleus of a Uranium-235 atom. It has 143 neutrons and 92 protons. A neutron has a mass of 1.0087 amu (atomic mass units), and a proton has a mass of 1.0073 amu. So the total mass should be 143x1.0087 amu + 92x1.0073 amu = 236.916 amu. But the mass of a Uranium-235 nucleus is only 235.0439 amu! There's 1.872 amu missing! That's like taking 100 blocks that weigh 1 lb each and building a castle with them, but the castle only weighs 90 lb. So where does that mass go?

Remember that E=mc². E is energy; m is mass; and c, to keep it simple, is just a number (about 300 million). What this means is that mass and energy are related. The missing mass has turned into energy, and that energy is being used to hold together the nucleus. This is what is known as strong nuclear force.

However, there are certain nuclei that are “unstable”, meaning that sometimes the strong nuclear force isn't strong enough to keep all that positive charge together. In these cases, magnetism will eventually win out and the nucleus will change to become more stable. There are different ways it can do this, but we'll focus on nuclear fission – when the nucleus breaks apart into smaller nuclei, creating smaller atoms. It turns out that since these smaller nuclei have less protons and hence less positive charge, they don't need as much energy to hold them together. When they are split apart, the energy that was holding them together is released and viola – you have nuclear power.

Now that you know the basics, stay tuned for next week when we'll discuss what it is about nuclear power that has everyone feeling so negative about protons.

How Big Is Your Footprint?

Have you ever stopped to wonder how much waste you generate?  Just out of curiosity, I wondered to myself today how much waste I put out driving back and forth from college.  Now don't get me wrong, I'm no economist, but the results astounded me.

Here's how my calculations went:

My vehicle holds about 20 gallons of gasoline.  Gasoline is comprised mostly of octane, or C8H18. (Yes, there are other hydrocarbons, alcohols, functional groups, and such in there, but it's pretty well represented just by octane.) The balanced equation for the combustion of octane is as follows:

2C8H18 + 25O2 →16CO2 + 18H2O

We'll say that gasoline has about the same density as water, or 1kg per liter.

So here's the math:

20 gallons x (3.8 liters per gallon) = 76 liters of octane

76 liters x (1kg per liter) = 76 kg of octane

76 kg x (1000 grams per kg) = 76,000 grams of octane

Using the molecular weight of octane,
76,000 grams x (1 mol per 114.224 g) = 664.21 mol (this is a measurement of how many molecules of octane are being burned. 1 mol = 6.022*1023 molecules.)

For every molecule of octane burned, 17 molecules of exhaust are produced. So,
664.21 mol of octane x (17 mol of exhaust per mol of octane) = 11291.57 mol of exhaust.

A mol of gas (like exhaust) at standard temperature and pressure (i.e. normal conditions) takes up 22.4 liters of volume. So,
11291.57 mol of exhaust x (22.4 liters per mol) = 252,931.168 liters of exhaust.

TWO HUNDRED FIFTY-THREE THOUSAND LITERS OF EXHAUST from one tank of gasoline.

Maybe tomorrow I'll ride my bike.