Saturday, May 25, 2013

On Kant and Kindness: What's the Point of Ethics, Anyway?

Immanuel Kant
Every so often I encounter an idea that stops me cold and makes me think, “Woah, if that's true I'm going to have to rethink all kinds of things.” These ideas aren't necessarily true, but they do demand to be considered. One that I've encountered recently is the way Kant thought about what makes an action moral or ethical (I use the two words as synonyms). To see how Kant thought about ethics, imagine a doctor who loves her work. What makes her happy is to help other people, and the more she helps them, the happier she is. That's an extremely moral person, right?

Not so fast, says Kant. Kant thought the only actions that can truly be considered moral are those based on a reasoned sense of duty, not on compassion or benevolence. To illustrate this, let's imagine another doctor. This one isn't especially compassionate, and it doesn't make her all that happy to help others. But she's not in it for the money, either. This doctor does her work out of a sense of duty. She believes that helping people is the right thing to do and the best way to spend her life, but she would much rather be a professional surfer. Kant would say it's she's who's acting morally. It's not that the first is being immoral. But she's simply doing what makes her happy, and it's a nice coincidence that what makes her happy helps others. It's the second doctor who's putting her desires aside to act in a way that she thinks is right.

That's an arresting thought. We tend to think of the best people as the ones who are the most selfless and kind, but we also admire people who put aside their desires to do what's right. Are people who do good out of a sense of duty really more ethical than people who do good because it makes them feel good? I don't know. I tend to think that while the doctor who helps people out of a sense of duty is very ethical and admirable, it would be even better if she could somehow cultivate compassion for people, and align her happiness with theirs. It would make her life easier, and probably make her a better doctor.

But the idea of acting according to principle, regardless of how it makes you feel, is pretty important, too. A whole lot of the time, what's obviously right doesn't align with what we want to do. Imagine you've recently been fired from your job, and you're wondering how you're going to pay next month's rent. Then you find a wallet with $2000 in it. Some people would never want to do anything but get the wallet to its owner. But not many, I suspect. Others would take the money and ditch the wallet without a second thought. Alas, there are plenty of those. But in between those two extremes are those who would really, really want to take the money, but don't because they think it would violate an ethical rule. They feel it's their duty is to find the owner of the wallet and give it back to them.

It's good that they feel that way, because their innate kindness toward strangers wouldn't have been enough to make them give the wallet back. Kindness and compassion are great, but they're probably too unreliable to use as the sole bases for ethics in a society. A sense of duty can be a very good thing, even if it isn't accompanied by any particular kindness.

But duty without kindness has serious pitfalls. What if the rules people feel duty bound to follow are bad ones? In Peter Singer's book, How Are We To Live, he mentions that Adolph Eichmann, one of the main architects of the Holocaust, claimed that he had been acting according to a Kantian sense of duty. Apparently Eichmann thought—based in part on his interpretation of Kant--that he shouldn't let sympathy interfere with his duty, which was, he thought, to be faithful to his country by carrying out its horrific Nazi policies. He even talked about how he had occasionally felt sympathy for Jews he saw being killed, but suppressed it on Kantian grounds. At least, that's the story Eichmann told his captors, and maybe himself. But it does seem to be true that many rank and file Nazis who committed atrocities weren't sadistic, just heartlessly dutiful.

Of course, we can't blame Kant for how people misguidedly acted on his philosophy. Still, Kant does seem to have believed that we should never let our sympathy for others get in the way of our ethical duty to act according to universalizable standards. And this did lead him to some chilling conclusions. For example, imagine that a friend comes to your house and says someone is trying to kill them, and asks you to hide them. You do. Then the killer comes to your door and asks if your friend is inside. Should you lie to protect your friend? Kant thought not, because he thought lying was universally wrong, and that our duty to obey this universal law outweighs our feelings for our friend.

And that is clearly crazy. This a case where reason has gone too far, and should have brought compassion along with it. I admit that's not much of a refutation, logically speaking, but I bet you agree, so I'll move on to my main point. That's what the conundrum about the two doctors is really all about, which is: what should ethics be based on? Some people think ethics should be based on consequences—we act ethically because it leads to desirable outcomes. Thinking we should act ethically because it makes life better for conscious beings is an example of such a consequentialist position. Others, like Kant, think ethics should be based on reasoning about what laws should be universal, and then acting with a sense of duty to uphold those laws. This is the deontological (duty-based) theory of ethics. Then there are people, like Aristotle, who believe that ethics is all about having or cultivating certain virtues, or desirable personal traits. Most people would consider the kindness of the first doctor to be that sort of virtue. Of course, probably the majority of people in this country think about ethics in terms of religion. They may think ethics should be based on God's will or God's plan for us. I've talked quite a bit about religion and ethics in other posts, so for now I'm just going to focus on secular ethics.

Whenever you're pondering these questions it seems to me that you have to ask, “What's the ultimate point of acting ethically?” When I ask that, the consequentialist view is the only one that makes any sense to me. What could possibly be the point of either duty or virtue if they don't do any actual good in the world? In a world of robots who don't care what happens to them or anything else, what would be the point of kindness? What would be the point of following ethical laws? Are ethics even conceivable in a world without preferences; without pleasure and pain, or hopes and dreams? Don't get me wrong. Cultivating virtues, and making good ethical rules and following them even when we don't want to, are both good ideas. But at bottom the only reason I can imagine for doing those things is that they make life better for people or other sentient creatures who are capable of being happy and fulfilled in one set of circumstances and miserable in another. In the absence of consciousness and preference, ethics makes very little sense. If someone walked up to you and said, “The problem with Mars is that there are no ethics there,” you would think they were crazy. First, because a person saying such a thing out to a stranger out of the blue probably ain't quite right, and second, because Mars is a planet of rock and wind, with no life or consciousness. What need is there for ethics in a place like that?

In this era, when traditional religious ideas about morality have lost a great deal of their grip, people worry that people without religion will see no reason to act ethically. As the common paraphrase of Tolstoy goes, “If God is dead, all things are permitted.” It's a legitimate worry, because some people will conclude just that. But it's not a rational conclusion for them to make. First of all, if the only thing that is keeping you from murdering and thieving your way through life is the idea that God would disapprove or it, or that he will punish you with hellfire if you do it, then you aren't actually very moral. Second, whether there's a God or not, the world is full of thinking, feeling beings with preferences about what kind of life they want. As soon as you recognize that there are other beings in the world whose desires and dreams are every bit as real to them as yours are to you, you've recognized the need to consider ethics.

So what about the two doctors? Which one is more ethical? Heck, I don't know! The comparison is useful for isolating a philosophical point, but it's not clear that there's an answer. I'd say they're both quite ethical, because they're both doing things would good consequences. Perhaps the second one is explicitly basing her actions on ethical considerations more than the first one, but perhaps the first was just born with a better sense of what is ethical? The first is acting according to the virtue of kindness, and the second is acting according to duty (though dutifulness is a virtue, too, as long as it doesn't run away from compassion). Surely it doesn't make sense to belittle sympathy or similar emotions as engines of good behavior? Would it really make sense to have a world where people ignored their sympathies and acted solely based on duty, because that is somehow a truer display of ethics? If the emotionally indifferent doctor is more ethical than the compassionate one, then would a downright misanthropic doctor (who still does good work) be the most ethical of all? If so, do we want a world full of people like that? Surely not. Why not simply cultivate kindness and make being decent easier for everyone? No easy task, or course, but still.

One thing is clear--if you had to choose which doctor you wanted to be, you would pick the first one, who's simply happy when she is doing good. It would be a better world if we could find a way of cultivating that kind of effortless goodness, both for the people benefiting from the do-gooders, and the do-gooders themselves (and surely their happiness counts, too?) A sense of duty is still necessary too, for times when temptation makes people forget the interests of others. But the idea of rules or duty for their own sake makes no sense, at least not to me. Those are means to other ends, not ends in themselves. In fact, kindness and other virtues, as well as rules and duties, are all just means of making the world a better place to live in. That's the real point, the ultimate end, and whatever gets us closer to it is surely a good thing. Both doctors are good people, taking different paths toward the same goal. I imagine Kant would disagree, and I'm quite sure he was smarter than I am. But, then, I wouldn't hesitate to lie to a murderer to save a life. And I bet Kant wouldn't have, either.

Friday, May 17, 2013

"Unnatural Acts" and the Sins of Sodom: Some Bad Arguments against Homosexuality

In the last few days, I've run into people using two of the most common arguments against homosexuality: saying it's unnatural, and pointing to the story of Sodom and Gomorrah. Both arguments are still quite common, and a whole bunch of people think they give them a license to tell others who they can love and marry. It seems to me that an argument better be pretty good if you're going to use it to tell other people how they can live their life. And neither of these arguments come close.

First, the "unnatural" claim (I'm going to leave aside the obvious point that homosexuality might not be unnatural). Religious and non-religious people are always using the "Natural = Good/Unnatural = Bad" argument, sometimes called the Appeal to Nature argument, to divide the world between good things and bad things. Up to a point, this makes some sense. For example, we evolved to eat a certain kind of food, which is derived almost exclusively from other living things. That means it would be unnatural to try to eat, say, a handful of asbestos fibers. In this case, unnatural is bad, because our bodies aren't equipped to eat asbestos. So, what's natural/unnatural often correlates with what's good/bad. But the correlation is far from perfect. What's natural isn't necessarily good, and what's unnatural isn't necessarily bad. Arsenic, bubonic plague, tornadoes, and brain-eating amoebas are all perfectly natural. Come to think of it, so is asbestos. Some common, natural animal behaviors include infanticide, forced copulation, internal parasitism, and eating prey while it is still alive and kicking. Unnatural things include running water, electrical appliances, C-sections that save the lives of mothers and babies, and--older male readers take note--Viagra.

People are right to admire nature's beauty and harmony, because it has both of those things in spades. And since we evolved to live in a certain kind of natural world, we disregard what is natural for us at some peril. But nature also has an enormous amount of death, strife, and pain. So it's also perilous to assume that what is natural is good, and what is unnatural is bad. Whether something is natural or not should be one of many considerations in deciding what is good or bad, and not an absolute one. That's because it's not the main point, when it comes to most moral arguments. Our main concern is not whether something is natural or unnatural, but whether it is good or bad. And what that really means, I think, is: does it improve the welfare of conscious beings, or decrease it?

The real question when deciding whether something like homosexuality is immoral is: "Does it do harm?" I don't think it does. Sure, gay people often don't reproduce, but in a world that went from 6 to 7 billion people in 13 years, I don't think that's a bad thing. There's no shortage of people on this planet. Even if you could clearly show that homosexuality caused harm in some way, well, heterosexuality causes quite a few problems itself. Besides, it would have to be something pretty harmful to justify telling people that they have to abstain from sex and love--which most people consider among the most important things in life--or try to force themselves to be heterosexual. I don't know about you, but can't imagine changing my sexual orientation through sheer force of will. Maybe some of my fellow heterosexuals can (that would explain how so many of them can claim homosexuality is a choice, I guess). In any case, my point is that you can't say homosexuality is wrong simply by saying it's unnatural. What's unnatural isn't necessarily wrong, and what's natural isn't necessarily right.

Now, over to Sodom and Gomorrah. Obviously, the word "sodomy" comes from Sodom, one of the Biblical "Cities on the Plain" that may have existed along the Jordan River plain, north of the Dead Sea (archaeologists argue about whether it ever existed or not). In the book of Genesis, Abraham and his nephew Lot part ways amiably, because their herds have grown too large for the land to support both of them. Lot goes to Sodom, a city whose people were said to be "wicked, great sinners against the Lord". God soon tells Abraham that he intends to destroy Sodom for its sinfulness. Abraham begs him to spare it if he can find 50 righteous men in the city. God agrees, and then Abraham talks him down to ten. But apparently there aren't ten righteous men in Sodom, because God sends two "men" (usually interpreted as angels) to destroy it. The angels meet Lot, who invites them into his home.

That's when things turn nasty. The men of Sodom gather around outside Lot's house and demand that he hand over the angels so that they may "know" them (presumably in the Biblical sense). Lot refuses, and instead offers his two virgin daughters to the mob, to "do to them as you please". The mob refuses and tries to force their way in, and the angels strike them blind. Then they tell Lot to flee the city with his family, and not look back. But his wife does look back, and is turned into a pillar of salt (the area has naturally occurring pillars of salt, which is probably the basis for this part of the story). Then the Lord rains fire and brimstone down on Sodom, Gomorrah, and most of the other cities on the plain. Later, Lot's daughters get him drunk and have sex with him, and have his children.

For over two thousand years, up to this day, this story has been interpreted as a cautionary tale about the evils of homosexuality and the destruction that the Lord will visit on societies that allow it. But wait a just a minute here. Here we have a story where the main character, Lot, is held up as one of the only righteous men in the wicked city. A man who offers his daughters to an angry mob, to be raped, and later on bears children with those same daughters. Should we really look to this tale as a guide to morality? Nobody looks very moral in this story to me. Even God seems needlessly harsh (as he often does in the Old Testament). Did Lot's wife really deserve to be turned to salt? What kind of moral lesson is this tale, anyway?

Still, it's clear that the inhabitants of Sodom were being pretty awful. If there is such a thing as angels, I think we can all agree that gang-raping them is a bad thing. But it's strange that what people remember as being bad in the story is the homosexuality, not the coercion and attempted rape. Those things, unlike homosexuality, are clearly bad because they hurt people. Homosexuality is very different. Homosexual relationships between consenting adults don't seem to hurt people (or they wouldn't if others wouldn't freak out so much about them). What kind of skewed sense of morality causes people to read this story, and remember homosexuality as the worst behavior in it?

Now, there are going to be people reading this who think, "Well, maybe homosexuality isn't as bad as the other stuff in the story, but it's still bad, and that's one point of the story". Maybe that's one way the author of the story intended it.  I wouldn't be surprised, but then, he was a member of a violent, sexist, and superstitious society. Why should we put so much stock in his opinion? Haven't we learned anything about morality in the last 2500 years or so? Maybe this is one of those things in the Bible that nobody should take seriously as a guide to morality. You can't deny that there are such passages, and I don't care how religious you are. Unless, for example, you're prepared to agree that if someone rapes your daughter, the right thing to do is marry her to him, as Deuteronomy 22:25 commands. I'm pretty sure you aren't going to go for that, even if you claim to believe the Bible is literally true and inerrant. It's a bad rule. Similarly, the story of Sodom and Gomorrah is simply a bad moral lesson.

But there are always people who love to denounce others, especially if they think they might be enjoying themselves. I don't understand this impulse. It seems to me that people make a terrible mistake when they think of morality in negative terms, as a list of  "THINGS YOU SHOULD NOT DO". Morality isn't about keeping people from enjoying life, or it shouldn't be. In fact, the whole point of morality, as far as I'm concerned, is to make life worth living for as many people as possible. Morality is about making life better, not worse. But, let me be clear. I'm not advocating the kind of simplistic utilitarianism that prescribes doing whatever causes the most total benefit, on average. I don't think, for example, that it's right to kill and harvest one person's organs to save the lives of 5 others.  Individual rights are important. But rights aren't important in and of themselves. They're important because respecting people's rights will make life better in the long run.

Some religious people might think morality is about doing what God wants us to do, regardless of our happiness. But wouldn't a good God want us to do what makes life good (if not in this life, at least in the next one?). I suppose you could say we are a part of God's big plan, and that plan may not include our individual happiness. To which I would respond: prove it. If you want to base your morality on arguable theological ideas, that's your prerogative, but I don't think it gives you the right to impose it on others. The only certain criteria for a morally bad act--certain enough that the act should be outlawed--is that it clearly hurts people.

I'm writing this because I have a lot of gay friends, and I hate seeing them hurt by discriminatory laws and attitudes based on shaky ideas of morality, like simple-minded appeals to nature or morally questionable Bible stories. If you want to impose your morals on other people, to the detriment of their happiness, you better be able to make an airtight argument that meddling in their lives is morally justified. When it comes to homosexuality, I've never seen an argument that comes close. My larger point, however, is about the whole reason for having morals. A moral code that doesn't actually make life better is a moral code that makes no sense (alas, it's also a moral code that's extremely common). What makes something bad is not that it's unnatural, or that it violates some arbitrary rule from God, but that it causes harm and makes life worse. If it doesn't do those things, then I just can't see how it's bad.

Sunday, May 12, 2013

Touring Orion: Astronomy and the Depth of Wonder

When I heard the learn’d astronomer,
When the proofs, the figures, were ranged in columns before me,
When I was shown the charts and diagrams, to add, divide, and measure them,
When I sitting heard the astronomer where he lectured with much applause in the lecture-room,
How soon unaccountable I became tired and sick,
Till rising and gliding out I wander’d off by myself,
In the mystical moist night-air, and from time to time,
Look’d up in perfect silence at the stars.
- Walt Whitman, When I Heard the Learn'd Astronomer

People look at you funny when you talk about outer space. The artists and poets think you're too cold and analytical, and others think you're a nerdy space cadet who should come down to earth. People think pondering the depths of space just isn't cool. But, then, people can be pretty silly. And as much as I love Walt Whitman, he was being a little silly, too. His mistake in the poem above was thinking we have to choose between science and the experience of gazing in awe at the night sky. It's a false dichotomy. You can have both at the same time, if you just decide your mind is big enough to hold them both. Besides, science can make the experience of looking up at a night sky all the more awe-inspiring, by telling you just how ancient and far away those stars really are.

So, if you're one of those people who think space is either too square or too dorky, I'd like to try to convince you otherwise.

First, let's just walk out and take a look at the night sky, like Mr. Whitman did. Imagine that we're walking out in the early spring, to see something like the image below. There's the Milky Way arched across the sky, and Orion the hunter with his bow outstretched. The little cluster of stars on the right is the Pleiades, and the bright star on the left is Sirius, the Dog Star.  Between Orion and the Pleiades is Jupiter, which is not a star at all, but the biggest planet in the solar system. If you had a pair of binoculars, you could look up and see four of it's moons. It's the first warm night of the year, and the frogs are singing off in the distance. Altogether, it's a glorious, overwhelming experience.

But what if we could look deeper? What if we could take a closer look at those distant worlds, and see them as more than just points of light? Well, we can, at least in our imaginations. And the reason we can is all those learn'd astronomers with their charts and figures, which helped them figure out so much about what's really going on out there.

So let's take an imaginary trip, straight into Orion and beyond, to see how much deeper the sky is than we can see with our naked eyes. First, let's consult a map to see where we're going. Here's our itinerary:

The trip seems to jump around so much because we're starting with the closest objects, and making our way toward the most distant ones. We're going to start with Jupiter, and then go deeper and deeper into space, in the general direction of Orion. I'm not going to dwell on the planets much, because most people learned those in school pretty well. What most people don't know is how things are arranged out beyond the solar system. That's where we're headed, but we'll stop at Jupiter, since it's on the way.

Jupiter is the first and largest of the gas giant planets out beyond Mars and the asteroid belt. It's not a solid object, except at its rocky core. Its famous bands are formed by rising and falling clouds of ammonia ice and ammonium hydrosulfide. Jupiter is the big boy of the solar system--over 1400 Earths would fit inside it, and it's twice as massive as all the other planets combined.

But Jupiter is a pipsqueak compared to the sun, which is over 1000 times as massive. Really, the planets are just bits of detritus around the sun, and even the sun isn't that impressive by astronomical standards. This becomes obvious if we look backward and remove the constellation lines, to see the inner solar system as it would really look from Jupiter. The sun just looks like an unusually bright yellow star from here, and we wouldn't even recognize the inner planets--including our own--if they weren't labeled. But then, we've come a long way, by our normal standards. To put the distance to Jupiter in perspective, if you could point your car there and start driving at a steady 75 miles per hour, it would take several hundred years to get there. You would need to bring a lot of music.

But we've barely gotten started. Our next stop is Sirius, which is 8.6 light years away--a whole different level of far away. A beam of light, which can goes fast enough to circle the world over 7 times a second, would take 8.6 years to get to Sirius. And Sirius is one of the closest stars to Earth. If the Voyager 1 spacecraft, which has just reached the edge our solar system after 35 years, were heading for Sirius, it would take about 180,000 years to arrive. Travel to the stars is still pure science fiction.

Luckily, we're taking an imaginary trip, so we can get to Sirius in no time at all. As we approach, we see the single point of blue-white light resolve into two stars. It turns out Sirius is a binary star system, with two stars orbiting a common center of mass. The bigger one, Sirius A, is about twice as massive as our sun, but it's much hotter, and thus 25 times as bright. Sirius B is an entirely different story. It's a white dwarf star, slightly smaller than the earth, but more massive than the sun. In other words, it's astoundingly dense--a piece of it the size of a sugar cube would weigh about a ton. Try dropping that in your coffee.

White dwarfs like Sirius B are the shrunken cores of larger, deceased stars. Around 120 million years ago, Sirius B resembled Sirius A, but it became unstable as it used up all its fuel. This caused it to swell up into a huge red giant star, and eventually puff its outer layers of gas into space, creating a luminous nebula which has long since dispersed. All that remained was the hot, tiny core, which will burn with stored heat for billions of years to come, until it finally cools down into cold, dark object called a black dwarf.

The next leg of the trip is a big one. We're going to the Pleiades, or Seven Sisters, a group of stars at least 390 light years from Earth. That means the light we now see on earth when we look at them has been traveling through space since around the time the Mayflower landed. Unlike most constellations, the Pleiades are an actual group of stars, called an open cluster. But I like to think of them as a litter, because they are siblings--born together in a giant cloud of collapsing gas. The bright blue stars we see are blue giants, which are bigger, hotter, and far brighter than most of the other 1000 or so stars in the cluster. Blue giants are like rock stars, living hard and dying young, burning through their fuel at a furious pace. Some of the ones in the Pleiades are already showing their age, and they're a mere 100 million years old. The smaller yellow and red stars take the slow and steady approach. They will live on for billions of years, some of them for many times the current age of the universe.

Rogelio Bernal Andreo (Creative Commons Att. Share Alike)
Now it's time to head for Orion itself. First, let's take another, closer look at Orion as it appears from earth.  The amazing photo to the right is a long-exposure mosaic showing the clouds of gas and dust that fill the constellation. The red clouds, called emission nebula, glow because they're heated up by the stars forming in and around them. If you look closely, you can see darker clouds too, which show themselves by blocking the stars behind them. The Orion region is one of the most active regions of star formation known. In fact, some of the stars visible around Orion's belt and sword were born together out of those clouds. It's unusual for the stars in a constellation to be related, but many of the stars in Orion are, possibly including the next two we're going to meet.

Our next stop is Betelgeuse, the enormous red supergiant that defines Orion's left shoulder. When I say Betelgeuse is enormous, I mean it's really just stupendously huge. If the center of Betelgeuse were where our sun is, it would swallow all the planets up through Mars, and come nearly to the orbit of Jupiter. But Betelgeuse is nearing the end of its life, and it's really starting to fall apart. It roils and pulsates, belching plumes of gas as large as our solar system. In about a million years, it will collapse and then explode as a supernova. Anyone still around on earth will see it shine as bright as the moon for a few weeks, even though it's 640 light years away.

The brilliant blue star that forms Orion's right foot is called Rigel. It's a young blue supergiant star, around 8 million years old. It's no small fry itself. If the sun were the size of a BB, Rigel would be about the width of a beach ball. It's not nearly as big as Betelgeuse, but it's big. It's also tremendously bright--at least 117,000 times as bright as the sun. Its brilliance caused partly by its size, but mostly by its intense heat (with stars, size is not nearly as important as heat). Rigel's brilliance is the reason we see it so clearly, even though it's about 860 light years away, and the light we see left it around the time Genghis Khan was born.

If you walk out on a clear night and look up at Orion, the middle of his sword is actually not a star at all, but a glowing red cloud called the Orion Nebula. It's one of the most spectacular star formation sites known, so let's go take a closer look. As we approach the nebula, about 1,344 light years from earth, we see that it's really a bright cavity in a more extensive cloud. It's like an amphitheater full of thousands of stars. The brightest, as usual, are blue giants and supergiants, but there are stars of all other sizes and temperatures being born too. Some are still wrapped in discs of dusty debris which will one day aggregate into planets. Others are in the so-called bipolar outflow stage, with great jets of gas shooting out from each pole. Astronomers have even seen brown dwarfs, balls of gas too small for fusion reactions to ignite, so they never quite turn into stars. If we could look into the cloud with infrared vision (and astronomers can do just that) we would see even younger stars forming from the dense gas. After they form, stellar winds of radiation will push back and illuminate the gas, deepening the cavity of the Orion Nebula. This, in turn, will cause gas further back in the cloud to collapse toward stardom. Starbirth propagates itself like spreading wildfire, so that as we move deeper and deeper into Orion, we find younger stars. Looking back toward Earth, stars like Rigel and Betelgeuse may be older progeny of the same great cloud across Orion, born in clusters like the stars of the Orion Nebula, but drifting away from their siblings over millions of years.

We've gone straight through the heart of Orion, and now we're on the other side. Let's keep going, to see what we can see. Our next stop, the Crab Nebula, is many times farther away than anything we've seen so far--6,500 light years. That means we see it as it was about a thousand years before the Sumerians built the world's first cities. The Crab Nebula is a completely different animal than the Orion Nebula. It's what's left over from a supernova explosions in 1054 AD. Chinese astronomers at the time recorded a "guest star", which appeared all the sudden, bright enough to be seen in the daytime. What we see today is a cloud of glowing gas 11 light years across, and still expanding at about 1,500 kilometers per second. Yes, per second. At the center of the cloud is the leftover core of the old star. When the core collapsed and then rebounded, the pressure was so great that it collapsed protons and electrons into neutrons, forming a ball of neutrons as dense as an atomic nucleus, but as large as a city. It's still spinning about 30 times a second, pouring radiation out from each magnetic pole. We see this radiation as rapid-fire pulses, so this kind of neutron star is also known as a pulsar. It's hard to believe anything this extreme really exist out there, but nature is full of surprises.

In the long history of the Milky Way galaxy, there have been countless supernova explosions like the one that created the Crab Nebula. In fact, we owe our existence to them. When the universe was born in the Big Bang, the only elements that existed were hydrogen, helium, and traces of lithium. Then, when the first stars lit up, they burned by fusing hydrogen and helium into heavier elements, creating the rest of the periodic table--the atomic alphabet that makes life possible. All stars create a few heavier elements, but some of the most crucial elements for life, including sulfur, sodium, and potassium, are created in supernova explosions. We are, quite literally, made of stardust--stardust blasted into space in some of the most violent explosions in the universe. It's a pretty amazing heritage, and we share it with everything in the solar system.

Maybe we've come far enough for now. We're over 6,500 light years from home, farther than light could have traveled in all of written history. But just how far is that, in the grand scheme of things? Not very. In the picture below, the yellow line shows roughly where we have been so far. Except for the Crab Nebula, which is in the Perseus Arm of the Milky Way, everything we saw on our tour was in the little sub-arm of the galaxy known as the Orion Spur.

The galaxy as a whole is over 100 thousand light years across, and it contains at least 200 billion stars--more than you could count in several lifetimes. We've only seen a tiny section of it, and then only in our imaginations. A real trip like this is still completely beyond our grasp, and will be for the foreseeable future. And the Milky Way is just one galaxy; part of a small group of galaxies on the edge of a giant cluster that contains thousands of others, in a universe that contains untold numbers of such clusters. We could keep on traveling outward, to see where our galaxy fits in with others, but we've surely gone far enough for now. 

Now, here's the question. If you walk out one night and look up at Orion, does the tour we just took make  looking up at a night sky somehow less amazing? I don't see how it could. For me, it just makes a great thing that much greater, showing us wonders we never could have imagined if learn'd astronomers hadn't made all those charts and figures.