Good Greeks and Bad and How They Changed the Universe

Astronomical image, t.b.a.Posted Jan. 30, 2009 – Our grasp of the structure and immensity of the cosmos is hand-me-down knowledge that started 5,000 years ago, with the Babylonians and Egyptians, who accurately noted the cycles of the sun and moon. But through it all, only the ancient Greeks went beyond merely observing celestial patterns. They were the first to come up with correct original explanations. Let’s pay some of them a tribute now, in chronological order.

Anaxagoras (450 BC) correctly believed that moon reflects light from the sun, and therefore understood why the moon darkens during an eclipse.

Heracleides (350 BC) was the first to propose that, since Mercury and Venus stay so close to the sun, they might orbit it and that the Earth might rotate on an axis.

Eudoxus (in 375 BC) originated a geometric method of calculating the distance from the Earth to the Sun and Moon.

Aristotle (340 BC) is famous, but he set back science for 2000 years with his geocentric model of the universe, which went unquestioned until the time of Galileo. But some of his other writings were correct, like when he said that the Earth was not flat, but spherical.

Aristarchus (265 BC) was among the greatest of the great, the first to correctly determine the relative sizes of the Earth, Sun, and Moon. And once he realized that the sun is far larger than the Earth, he proposed that the Sun, and not Earth, was the center of the solar system. Aristarchus wins the cigar for the heliocentric model.

Eratosthenes (200 BC) was another genius – the first person to correctly measure the size of the Earth. He used the angle of the sun’s shadow at noon in two different towns, and the distance between the towns to set up a proportion with the 360 degrees in a circle and the unknown size of our planet.

Ptolemy (170 AD) is famous, despite being wrong about nearly everything. Ptolemy supported a geocentric universe, which unfortunately became a religious principle for 1,700 years.

Hipparchus (130 BC) discovered the 26-century wobble of Earth’s axis (now called precession) and created the first accurate star catalog, using a system of dividing stars into 6 magnitudes of brightness, which is still used today. He also determined the length of a year to within 6 minutes.

In other words, astronomy may be Greek to you. But it wasn’t to those guys.

The ultimate icebox

Posted Jan. 30, 2009 – Living in rural upstate New York, I’m very familiar with temperature extremes. Since 1974, I’ve mostly heated with wood. Sounds romantic, but we all know better. I grab icy logs barehanded and lug `em to the house, where any remaining wrist hairs are burned off as I toss ’em in. En route I peer at the frosty January sky, its stars seemingly detached from the exercise in hot and cold abuse I endure for the sake of economy.

But on second thought, Orion and his friends experience the same thing. For what are we seeing in the winter sky if not an immense display of temperature extremes and fuel economics? Giant blue stars, like Rigel marking Orion’s foot, are among the hottest things the eye can see. Rigel emits the same blinding brilliance as 60,000 suns. Such energy output doesn’t come cheaply. Look again in just a half billion years and there’ll be no sign of Rigel, for it’s squandering its resources like a giant Hummer.

More typical stars emit only a sleepy 10% of the sun’s light. Using their nuclear fuel sparingly, they’ll live almost forever. Many have been shining since soon after the Big Bang, and they’ll still be alive ten billion years from now, long after our sun has metamorphosed into a frozen black dwarf.

These red dwarfs are more numerous than all other stellar varieties combined. Of the 100 nearest stars to Earth, 82 are of this type. Yet a glance upward reveals no trace of them. They’re just too cool and dim. Even telescopes only detect the nearest examples.
So the night sky fools us with a false picture of the galaxy’s stellar citizens. We merely see the lighthouses, the energy abusers. Truly typical suns, the thrifty ones, are utterly invisible, a hidden majority.

But the very coolest stars aren’t even those common superfaint ones. For a really cool customer, you want a carbon star. A fine example lurks just below Orion, in the pretty constellation of Lepus the Hare. Its name is R. I’m not protecting its identity. R of the constellation Lepus, or R leporis, changes its brightness, and such unstable stars have letter-names. Cool? R is extraordinary. It’s so stingy with its internal fireplace that it appears dramatically coal-red through any small telescope. In fact, finding it is as simple as sweeping a ‘scope below Orion, along an extended line from the rightmost belt star through Rigel, until you come to a crimson star. Such stars are cool enough to be surrounded by water vapor. Steam.

Yet we still haven’t reached the absolute cosmic extremes. The hottest thing anyone now living has ever seen was Supernova 1987A. I traveled to the equator to view it, a dim pinpoint that dominated its entire parent galaxy, emitting more light than a million suns. This was the only naked-eye supernova in three centuries. Supernovas are so hot that, like an alchemist’s lab, lead and iodine are created out of lighter elements, a task even the hottest normal stars can’t accomplish.

The other extreme, the absolute coldest stars of the night, are black dwarfs, not to be confused with black holes. But nobody sees them. They emit no light. You could lie on their surface and feel no heat. Staying warm could be a major problem. Imagine trying to light a campfire on the surface of a star? (A wonderful image, but not easy without an atmosphere.)
But we don’t even have to go as far as the stars to find unpleasant temperature extremes. Venus, now beautifully dominating the evening twilight, bakes at a steady 900 degrees, hotter than an oven. Neptune’s moon Triton, the coldest place in the solar system, shivers at a numbing -400.

And so it goes. No comfort zone. No room temperature anywhere in the known universe. The winter sky gives the appearance of a black frozen expanse punctuated by islands of fiery hell. And that’s just how it is. It makes my own little outings into fire and ice seem a little more bearable. They’re just a reflection of the larger universe, a momentary step away from the odd oasis of our comfortable Earth.

Bubble Land

Posted Oct. 25, 2008 – Bubbleland. We need a new branch of astronomy. We’ve got solar science, cosmology, spectroscopy, photometry. We’ve got optics, planetary studies, lots of categories. But we need a new one. Let’s call it Bubbleland.

Bubbleland is for things totally outside our understanding, places where we now provide the public with technical-sounding vacuity. For example, what existed before the Big Bang. I get that question a lot from students, and I’ll admit to being guilty of reciting the standard speech. “The Big Bang,” I explain grandly, “created time as well as space. Since there was no time before the Big Bang, your question is meaningless.”

The student is silenced. The class continues. The professor obviously knows something wonderfully profound. But I can’t do it any more. The next time some one asks, I’ll tell the truth: “Nobody has the foggiest idea what happened the Tuesday before the Big Bang. That whole domain is part of Bubbleland.” Then the class will nod, and really understand. Ah, yes, Bubbleland. The realm beyond the present reach of science.

Anyone attending a cosmology lecture can tell when the speaker arrives at Bubbleland. “It’s not galaxy clusters that travel outward,” he’ll say pedantically, “but space itself that grows larger. The galaxies don’t actually move.”

So here I am thinking, wait a minute. Are we at a Daffy Duck convention? Is this guy saying that empty space, nothingness, a vacuum, is capable of growing like a petunia, independently of the universe’s mass and energy? If so, then suppose nothingness alone existed ( – a contradiction in itself). If there were no galaxies, atoms, or even light in the universe, just space, could you still claim that the emptiness was getting bigger? What could that mean? And if you do critically need galaxy groups to define the increasing emptiness between them, why then insist they are not part of the process? (Actually, some Relativity experts, such as Dr. David Nightingale, co-author of “A Short Course on General Relativity,” are even uncomfortable with our exclusion of “local space” from the universe’s expansion.)

Or take singularities at the hearts of Black Holes. When explaining what happens to a massive collapsing star, physicists usually say that it achieves infinite density and zero dimension. When I’ve laid that on students, the funny thing is, they buy it. None make the lusty up and down hand motion some people (mostly men) employ to express incredulity, when recognizing a fish tale. My fantasy is to witness the following scene at a large lecture hall. First, the professor didactically informs the class that a singularity achieves infinite density and no volume. Then, suddenly, all 150 students silently rise and simultaneously make the “c’mon now” hand gesture.

Reality check: nothing can be infinitely dense, except our gullibility, as when we imagine that a politician said something substantive. And “zero volume” has no place in this universe, except as wishful thinking when confronting a teenager’s stereo. Obviously, a process beyond our present understanding must happen with singularities. Perhaps other dimensions come into play, in which case the collapsed star deserts our reality altogether. In truth, we have no clue. We should say we have no clue. But since there is no official category for what happens to singularities, we’ll just say they enter Bubbleland and everyone will understand.

Quantum mechanics has Bubbleland practically reserved to itself. You do the standard experiment and fire electrons or photons through slits onto a background screen, and get the classic interference pattern that proves these items are waves, or at least act that way this afternoon. Now the spooky part. Fire just a single electron at a time at the screen. STILL you get the interference pattern. The electron is interfering with others. Problem: There ARE no others. Only one electron is in the device at a time. With what is it interfering?

Nobody has ever answered this. It defies common sense. This (and many other quantum effects, such as when particles are in “superposition” or when they inexplicably randomize as if to deliberately hide information from us, or when they “entangle” with a distant particle so that act of measuring one instantaneously affects the other) demonstrate that normal logic sometimes fails on the subatomic level. Common sense is apparently the wrong tool – a little like trying to use a hammer to tighten a nut. Our brains created logic to deal with mortgages and cheeseburgers, not electrons. The honest answer is: This is just the way the tiny kingdom works. Yet there prevails a scientific pretense that we’ve got the whole thing covered, and don’t worry we’re really on top of this.
Yeah, right. In science, the simplest explanation is usually the correct one, and the simplest solution is that electrons live in Bubbleland.

Recently a few maverick physicists have come right out and admitted that the interference-when-there’s-nothing-there business must be confronted. They’ve suggested that perhaps numerous neighbor dimensions exist, alternate realities that lurk so closely next door, perhaps just a hair out of “phase” with our own, that our electrons interfere just enough with theirs to produce these strange interactive patterns. Yes, that’s probably wacky and wrong. But it’s good that some are finally facing the enormity of the antilogic.

We could go on and on. The late Carl Sagan, whom I love and admire, nonetheless said “Now that we’ve explained how life began, there’s no place for God.” Well, let’s leave God out of this and just address science’s explanation of life’s genesis. The prevailing account posits a mixing of organic molecules, the arrival of amino acids on comets from space, some accidental combinations, and then the great denoument: “and somehow life arose.”

Beep! Hold it! That “somehow” may be only one little word embedded among the thousands comprising the “explanation,” but it changes the whole thing to: “We haven’t a clue.” How consciousness or self-awareness can arise from amino acids remains as deep a mystery as it ever was. But since we do not want our experts to stand mute and nonplussed, we have now supplied an out. They do not have to utter the dreaded “I don’t know.”

Finally they can explain our origins.

We come from Bubbleland.

Pluto Remains Goofy

Posted Oct. 11, 2008 – Two years ago the International Astronomical Union (IAU) officially defined the word “planet” in a way that gave Pluto the boot. It was quick and seemingly final. NASA’s illustrated card containing all the planets, published for educators, was immediately reissued with Pluto airbrushed out, as if in an old Stalinist photo.

The demotion of Pluto to a “dwarf planet,” as if to join all the other Disney dwarfs, sparked considerable public controversy. Most folks even now lament Pluto’s disappearance; many astronomers have protested the IAU’s decision, as well. But many other planetary astronomers continue to support it.

I’m in the latter group. When we learned in 1978 just how tiny Pluto really is – only a bit more than half the diameter of our moon – and recall that its orbit has a wildly different appearance from all the other planets, we wondered if it truly belonged with the rest. But we stayed silent. Why disturb the long-established order? What was the harm?

But then new bodies started to be found beyond Pluto. Some virtually matched Pluto’s size, and finally astronomers found an even larger one. Suddenly we had Eris, Sedna, Quaoar, and now Makemake, and there was no end in sight. Now we had a problem. If Pluto remained a planet, and these others match or exceed Pluto’s size, and are just as round, they would have to be planets too. We’d have 13 planets, then soon 40, and eventually hundreds. Kids would no longer be able to memorize them.

It made far more sense to create new, separate categories. There’d be eight big planets, all orbiting within 7 ½ degrees of the Earth-Sun plane, with orbits that are more circular than oval. Then we’d have a separate “dwarf” class for much smaller bodies with very elliptical orbits. There’d be a third category for objects with too little weight to even be round in size, like the asteroids or the Kuiper Belt Objects (KBO’s) that probably number in the hundreds or even thousands, beyond Pluto.

Works for me. But some folks won’t give up. That’s why, in recognition of the need for further scientific debate on planet definition, more than 100 scientists and educators representing a wide range of viewpoints converged for three days at the Applied Physics Laboratory of Johns Hopkins University for “The Great Planet Debate: Science as Process” conference, sponsored by NASA, the Planetary Science Institute, The Planetary Society, and other heavy hitters.

Steve Maran, the official spokesperson, whom I know personally, wrote that “different positions were advocated, ranging from reworking the IAU definition (but yielding the same outcome of eight planets), replacing it with a geophysical-based definition (that would increase the number of planets well beyond eight), and rescinding the definition for planet altogether and focusing on defining subcategories for serving different purposes.”

It was almost a food fight. Neil Tyson of New York’s Natural History museum thought that the very word “planet” has outlived its usefulness and should be discarded, and replaced with a new term.

Renu Malhotra, a University of Arizona astronomer said, “I think the IAU made a mistake getting into the business of defining a widely used word, ‘planet,’ and sowing confusion thereby. Scientifically, the useful discussion would be about categories of planets (e.g., gaseous planets, rocky planets, dwarf planets, icy planets. . .and an individual celestial body may fall into more than one category). This approach would address the main practical problem of nomenclature without confusing the public about ‘planet’ itself.”

Still others thought the present situation is the best compromise.

The windup? The conference ended and no consensus was reached. Nothing will change. Too bad Mickey Mouse wasn’t around to sum it all up: Goodbye Pluto.

Terminal Velocity

Posted Jan. 3, 2007 – Terminal Velocity – It’s so catchy, they used it as a movie title. But “terminal velocity” is an important science concept that affects meteors, mankind, and the mass-extinctions that keep changing our planet. Plus it’s fun.

People who bewilderingly take up sky-diving learn that you don’t just keep falling faster and faster. By spreading arms and legs, a jumper stops picking up speed when she reaches 120 mph. It’s air, of course, that slows things down. Everything has its own terminal velocity: For raindrops it’s 23 miles an hour give or take. That’s the speed of falling rain, in case you ever wondered. (Actually it varies with the size of the drops. A light mist’s particles might fall at only a half inch per second, which is why clouds, made of tiny droplets, can just hang there).

There is no terminal velocity on airless bodies like Mercury or the Moon. On those places, meteoroids captured by gravity keep gaining speed, up to a maximum that happens to equal that world’s escape velocity, the speed necessary to wrench free from its gravity in a single upward blast. On Earth it’s 25,000 mph. In other words, if there were no air and you FELL to Earth from a great distance, even beyond the moon, you’d hit the ground at that same escape velocity speed of 25,000 mph. Throw a coin up and then catch it. The speed you tossed it exactly matches the speed it travels when it lands back in your hand. Gravity is like that. Symmetrical.

At first a falling person or meteor keeps gaining speed. After each second of falling, a plummetting stone or person goes another 22 miles an hour faster. Two seconds of dropping, achieved by falling from five-stories, causes a rock to hit the ground at 44 mph. The speed would just keep increasing, up to that maximum of 25,000 mph, if we had no atmosphere. We’ve already seen that air slows skydivers to 120 mph, a speed reached after falling 500 feet or 50 stories. That’s still fast, of course: The fatal human impact velocity ranges from 15 to 38 mph, so it’s hardly news that we humans can easily die in a fall. But that’s not true of all animals.

Some mammals like cats and squirrels have non-lethal terminal velocities. They can generally fall from any height and survive.
Here’s where we get back to astronomy. An incoming meteoroid can easily weigh a ton as it strikes our atmosphere; that was the estimated weight of the intruder that broke into dozens of fragments over a Chicago suburb on March 26, 2003. One piece invaded a teenager’s bedroom and broke a mirror. But it could have been much worse.

Meteoroids start out at a sizzling 7 to 44 miles per second relative to Earth. Fortunately, if the meteoroid weighs less than 8 tons — and nearly all of them do — air friction robs it of ALL its original speed. At a height of about 10 miles or 50,000 feet, it slows to just 2 or 3 miles per second, where it no longer glows. Nonetheless this 7,000 mph velocity, 3 to 6 times faster than a bullet, gives a one-pound meteor enough kinetic energy to easily destroy a jetliner. It hasn’t yet happened, but it could.

Continuing downward, now dark and unobservable, the meteoroid’s encounter with increasingly thick air slows it to a terminal velocity of about 240 mph. This is its final speed as it strikes the ground. That’s the speed at which nearly all meteorites land, plus or minus 20%. That’s still plenty fast – usually enough to pierce a roof and end up on the floor of some room. Buildings are penetrated every year or two in North America alone. Just since 2002, meteors have entered seven homes including two in the United States.

If the meteoroid weighs over 100,000 tons, our atmosphere won’t slow it down in the slightest: It slams into the ground at full cosmic velocity. This isn’t good, as the dinosaurs learned 65 million years ago. Yet even then, it’s not all doom and gloom. The
big ones shake up the biosphere, change the course of evolution, and create new bio-adventures. We mammals now rule the Earth solely because a single impactor had enough mass to make it immune to — terminal velocity.