Some years back (probably in the 1980s), I read an article by an astronomer who had collected lots of info on what was known of the distribution of mass of various sizes. It included a graph of mean size-vs-density, from monatomic H through various common small molecules, on to dust clouds, planets, and stars of various sizes, for our galaxy and a few others that had enough data to be useful. The graph had a long gap between planets (then known only for our solar system) and stars. The writer commented that there was no data at all in this gap, but the two ends did appear to extend to meet each other. So the obvious conjecture was that the distribution continued through the gap, and if so, it would come close to accounting for the "missing mass" needed to explain galaxy rotation.

This was pure conjecture, of course, and since little is actually known about planet formation outside our solar system, it wouldn't be surprising if the actual distribution has dips at various size ranges. But assuming that the gap has the value zero is not very sensible. The obvious approach would be to say that we don't actually know, and Further Research Is Needed.

I wonder if I could find that article again ...

So obviously there are no "planets" at all outside our solar system. ;-)

Maybe astronomers should just make up a new term for the concept. Or maybe several terms. After all, how useful is a term that includes both Mercury and Jupiter? Especially if it excludes Pluto, Titan and Sedna.

Yup. But the fossil record tends to be rather sketchy, and has little concern for what we consider our "needs".

Well, I don't think that quite matches the scientific concept of "species". By your definition, almost all species who were alive 50,000 years ago would be considered extinct, but hardly any biologists would agree with that. It's true that no humans alive today have 100% Neanderthal genes, but it's also nearly certain that there are no living humans with 100% Cro-Magnon genes, either. What happened would be considered a mixing of several human sub-species after migrations of one or more African groups into Eurasia. The Cro-Magnon sub-species disappeared, too, and modern human Caucasian and Asian sub-species are the results of that mixing. This sort of thing happens in species all the time, when conditions allow such genetic mixing, and the result is rarely considered a new species.

The fact is that modern humans are all one species. We can and do interbreed when groups mingle, and there are no groups of modern humans that are genetically incompatible. If sub-species "disappear" by genetic mixing, that is usually not called an extinction event. It's just the routine and normal mingling of subspecies.

An interesting contrast is that most North American duck species are known to hybridize occasionally, and the offspring are usually fertile. Does this mean they're really all one species? No, because they all mingle a lot, but interbreeding is rare. They have "behavioral" species-separation features, mostly based on female mate choice. The females are mostly all mottled brown (protective coloring), and the males often approach females of other species (because they can't tell them apart either ;-). But the females usually only accept males that have the "right" color markings; the others are ugly to them. This suffices to keep the species separate, though there is probably a very low level of genetic interchange between many of the species.

But humans aren't like this. Even if we do generally prefer mates in our own subspecies, most of us do find many members of other subspecies physically attractive, and we'll mate with them given the opportunity. This means that we really are all the same species. We now have good evidence that the Neandertals were merely another subspecies, because when they had the opportunity, they did interbreed with those slender, dark-skinned folks who migrated into their territory. They did so often enough to produce a new subspecies that's physically distinct from either of the earlier two (or three or more).

Hmmm ... You seem to have missed the even more "interesting" followup studies. I was a grad student working with some of those reasearchers, so I heard a bit about it. They took their adult solo-raised monkeys, who were highly asocial, and caged them for a while with infant monkeys. After a few months, they took those individuals and put them in the "social" cages with established groups of their own species -- and they behaved like normal, socialized monkeys.

So maybe we could try this with our "deprived" human children. Put them into a social setting (perhaps schools) with younger children, and watch their interactions. They aren't monkeys, of course, but we are all close relatives, so maybe it would work with them, and they'd become at least somewhat better-socialized humans after a while.

Or maybe humans are hopeless. We don't really know until we do such experiments on ourselves. But we do seem to have a population of good test subjects, and the results couldn't be much worse than what we've been doing. Imprisoning such young adults in response to minor mischief would seem to be exactly the wrong thing to do, if those monkey experiments apply to our species, too.

Maybe we should be looking at the origins of the "common carrier" concept, and learn how they apply to the current situation. A number of historians have written on this topic, and the history definitely applies to our modern network.

Part of the explanation of how "common carrier" arose is in the well-known phrase "kill the messenger". Centuries ago, this was a very real problem. It wasn't unusual for a prince (or other powerful personage) to respond to the receipt of a message he didn't like by punishing the poor fellow who delivered it. The carrier services replied to this in about the only way they could: They opened and read the messages, and if they thought the recipient would react by harming their carrier, they would "edit" the message. And when dealing with a recipient who had a bad history, they'd often sell the message's content to the enemies of the sender or receiver.

Eventually the smarter princes figured out that a reliable message service was worth more than the temporary enjoyment they got from torturing or killing the messenger. So some of them got together with the message services, and worked out an agreement: If a sender and receiver had both signed on with a message company, they could send "sealed" messages, which the message carriers would promise to deliver unopened. But this would only apply if the sender and receiver had both promised not to damage the carriers employees or equipment, etc., etc.

This worked out to the advantage of the princes who joined in such agreements, so the practice spread, and became known (in English) by the phrase "common carrier".

It's easy to see how this all might apply to our current topic. The ISPs are "carriers", but not "common carriers". They have a record of opening and reading our communications, and selling the contents to "enemies" like marketers and government agencies. We're now engaged in collecting evidence about this behavior, and publishing it openly. We should make it clear that, as long as the ISPs continue acting in such perfidious ways, we will continue to work to expose their behavior to the general public, including people they views as their enemies (or "competitors";-).

The parallels to the original situation aren't exact, but we might benefit by knowing the history and trying to find a similar solution that can work today.

Nah; it's not coming at all. It's here. And we're not gonna do a thing about it, so we'll just have to adapt. And migrate inland as our coastal areas slowly flood out.

Here in New England, one of the running jokes for the past decade or so has been for one person to ask what time the robins arrived this year, and another person says "They didn't return; they never left."

Actually, it is a bit more complicated than that. They're one of the many semi-migratory birds now. Part of the population heads south when it gets too cold. But we've seen robins in our yard (in a western suburb of Boston) every month of the year for about 10 years now, while before that, they were almost never seen in December, January or February. This was never exact, though, since their normal winter range did extend to around New York (and southern Nova Scotia ;-), and they were reported around Boston occasionally during warm winters. If you look in older bird books, you can see the robins' winter range ending somewhere south of us, depending on the book, while the current books show it extending to around the New Hampshire border.

But still, they're a locally obvious sign that the climate has shifted north by a hundred miles or so. And a casual search of the topic will make it clear that the US government and most of the population have no intention of doing anything serious to change the trend. The scientists have clearly pinned the blame on human activity, and the engineers point out that this means we now know how to control the climate if we want to. But we (collectively) don't want to.

(Then there's the local joke about all the folks in New Hampshire and Maine who think global warming sounds like a fine idea. Myself, I intend to plant a palm tree in our yard as soon as they become available in the nurseries, which may happen soon. ;-)

Heh. The example I like to use is to point out that killing one cow (or steer) means around 100 meals for a human, while eating a single slice of bread means you're responsible for the death of around 100 baby wheat plants (and probably a thousand living, breathing yeasts). Or: When you eat a hamburger, the meat part is entails less than .01 deaths, while the bread part caused the death of 100 to 1000 living creatures. So it's the vegetarians that are doing the real mass killing of prey.

Of course, this is a bit disingenuous, since the animal was probably fed on grains. But you can confuse this issue a bit by pointing out that cattle actually evolved as grazers mostly on the vegetative parts of their grassy "prey", not the seeds, and the plants can quickly regrow their leaves. Our feedlots are responsible for lots of deaths of little baby grains, true, but naturally-raised beef wouldn't do this. They do ingest at least a few of the seeds, so the issue isn't quite so clear, but it's basically accurate.

For some reason, people with ethical concerns about eating animals never seem to consider that plants are also living creatures. They seem to think that killing a single animal is something horrible, while there's nothing wrong with mass murder of baby grain plants. But you can confuse them a bit by talking about the plants as living creatures. Produce the image of an animal thousands of times our size, collecting our babies and tossing them alive into large hoppers, to be ground to a paste for the next meal. That's what we do to wheat plants. Hiding it in a grain mill doesn't change the fact.

Unfortunately, we're animals, and we can't get our food from the sun, air and dirt. To live, we must kill other living things and eat them. There are marginal cases, such as fruits that were evolved as animal food (to trick animals into transporting the seeds). But we humans can't live on fruit alone; we do have to kill other species for most of our food. This slightly complicates the moral and ethical issues.

And they all stood on Newton's shoulders.

No, wait; Newton came after Euclides. So Newton must have stood on his shoulders.

The human pyramid is getting rather tall, and a bit top-heavy.

Is it really? I've always read of it being a conclusion, not a postulate. Maybe I should finally go dig up the original papers and see who's been getting it wrong all along.

(Not that doing so would likely effect much in the ongoing flame wars, uh, I mean serious scientific discussions about such things. ;-)

So how would we know? Since it's all going on in secret, with severe punishments for anyone who speaks openly and truthfully about what they've been ordered to do, the only assumption that the proverbial "reasonable man" (or woman? ;-) would make is that we have no idea what they're planning to do to us next. This story could all be just "theater" to lead us to think that things are improving.

As long as the question "How would we know" is illegal for the participants to answer, we should simply assume the worst. We have a lot of history telling us what powerful leaders are likely to be doing to their own population when they enforce secrecy about their actions.

Of course it was and is. Why do you think they keep it secret from their own citizens (and law-enforcement agencies)?

One of my common experiences is that when I buy something online, for weeks after I get lots of ads for the thing that I just bought. In most cases, my reaction is "Why are you trying to sell this to me? I just bought one, and I won't be buying another for years."

If the folks writing the ad software can't figure out why (for durable rather than consumable goods) this doesn't make sales, it should be no surprise that all the rest of their software's decisions are equally goofy.

Actually, out in the wide-open rural spaces of the western US and Canada, "flying cars" are rather common and quite practical. Of course, they're usually called small planes, typically 2- or 4-seaters with some cargo space. And you'd usually want a ground car, too, since aircraft can be somewhat impractical on days of high winds, thunderstorms, etc. It's common for small-town shopping strips in that area to have a runway that's parallel to the main street, with stores in between, for the benefit of people using their small planes.

The reason so many people are complaining that most people live in urban areas nowadays, and having all your neighbors getting into the air during morning or evening rush hours is clearly impractical in the extreme.

I wonder where else in the world this is common. I've read similar comments from Australia, but I don't recall any info about other parts of the world. I'd think that such small planes could be practical in many other rural farming areas.

So what's with all these people estimating weeks to learn such things? I remember years back, when I took my first trip to the UK, and people talked about the weeks it'd take to learn to drive on the left side of the road. I found that, by the time I'd got a few blocks from the airport, maybe 5 minutes, I'd already stopped consciously thinking about it, and just drove like the others around me. Similarly with the speedometer the rest of the world; all it took was matching the numbers on the highways signs to the numbers on the dial, which worked right from the start, and felt natural after a few minutes.

The only real difficulty I've found with such things is learning the words in a different language. I've found that that can actually take a few weeks, though the vocabulary on traffic signs is generally so limited that it's not all that difficult a task. But I haven't seriously tried learning the terminology on signs in China or Japan yet. That might be a bit more of a challenge than, say, Finnish or Russian road signs. ;-)