Can rainbows cast reflections?

Many people are puzzled by my writing that a rainbow cannot cast its reflection. Some say they’ve seen rainbows and reflections, and wonder if I’m wrong, or else maybe I meant something else.

Nope. It’s true. You cannot see a rainbow and the reflection of that rainbow.

If you and I look at a car, we both see the same object. But a rainbow is a specific set of reflections and refractions within water droplets that essentially appear on the surface of an invisible cone whose radius is 42 degrees, whose orientation is the antisolar point, and whose apex is your eye, and your eye alone.

An apparent rainbow reflection in a mirror or on a lake, is that of a different rainbow. It may not even look like yours, since if it intercepts larger droplets it will be brighter but also deficient in blue. It is a different rainbow. Moreover, if the rainbow you’re seeing is nearby (as from a lawn sprinkler) then a mirror just ten feet to either side of you will show no reflection of it at all — no matter how the mirror is angled. It’ll show the same water droplets but with no rainbow within it.

Try it sometime. Or at least, think about it, and you’ll understand why you can never see a rainbow and also the reflection of that same rainbow.

Some readers have noted that they’ve seen or captured rainbows using cameras or reflector telescopes. But I never said that photons from rainbows somehow cannot bounce off glass: In these cases you’re seeing the rainbow, but not simultaneously seeing its reflection. The central point is that you cannot see a rainbow AND this same rainbow’s reflection. That’s because any reflection of an object is that object viewed from a different angle — and a rainbow, not being a real 3D object, cannot be viewed from any other angle except exactly where your eye (or camera) is located, completing the required geometry.

Try this link to an image and good explanation.

White Lines in the Sky: A Conspiracy?

Posted March 10, 2009 – As we all know, a jet doesn’t leave a white trail when it takes off. Nor does one appear when it’s low. But when it climbs high into very cold air the story changes.

nasa-contrailsJets burn kerosene. If you’ve ever used a kerosene heater, you’ve smelled exhaust products rising from the unit. These include water vapor, bits of carbon soot, some carbon compounds like methane, and trace amounts of impurities like metals. Well, when jets climb above 30,000 feet, the air is so cold at -40° that the exhaust’s water vapor instantly freezes into ice crystals. This is a contrail, a short white line behind the jet’s engines. It often dissipates in seconds as each crystal sublimates back to invisible vapor.

Jets even higher up zoom through such cold air, it takes a long time for the contrail ice to re-vaporize. Higher humidity can preserve it, too. The contrail lingers as a long white line across the entire sky. Winds often distort these into various curves. If the air mass is very humid, the exhaust’s soot particles enter the picture to act as condensation nuclei — like cloud seeding — to produce a thicker contrail as surrounding atmospheric vapor freezes as well.

In seconds the dense ice crystal formation spreads out and widens. It can expand into a long cloud that casts an odd shadow. Or, very rarely, in very high humidity, the contrail can act as the “starter yogurt” for a cloud covering the entire sky. People into meteorology have observed all these various contrail varieties since the 1930s. Contrail science is even taught in college courses, to show how an individual can assess the temperature and humidity at high altitudes.

These man-made pencil clouds reflect sunlight into space. Just a few years ago scientists were concerned that all the jet traffic would have a cooling effect on the planet. But global warming has made that issue go away. If anything, jet contrails are now seen as helpful.

Some folks regard contrails suspiciously. Apparently, many don’t know what they are. Several websites call the lines chemtrails, and think that the US military is deliberately spraying a substance upon the population.

This is silly for a number of reasons. First, if you’ve ever watched crop dusting you know that chemicals must be released very close to the ground. Released on high, they’d dissipate with the wind and take forever to get down; the concentration on the folks below would be zero. Second, my commercial pilot friends (along with the controllers at the FAA) would all have to go along with the plot, since they’d see the process happening. I’m a pilot and airplane owner myself: It’s NOT happening. Third, what would be the purpose? Some say mind control. But are people acting differently lately? Others say it’s to sow disease. But why would anyone want to do this? Who would go along with it? Finally, some say “chemtrails” are a government project to combat global warming. Nice, but then why should such a laudible effort be kept secret? Other web-based “explanations” involve even wackier stuff like electromagnetic rays.

Logic never placates the truly paranoid, and discussions are rarely satisfying. Those who “believe” WANT to believe, and claim soil tests show that dangerous substances have been found beneath the planes. But again, nothing released from 40,000 feet would ever reach the ground except diluted to zero. And, more to the point, the videos of these supposed “chemtrails” shown on the scare web sites are actually a common type of contrail. The believers claim they’ve only started around 1998 – but I’ve observed those “spreading out” contrails for over 40 years. They’re not new. They’re contrails. No mystery, and nothing sinister here at all.

Does a Falling Free Make a Sound?

Posted March 10, 2009 – The Sound of a Falling Tree

Astronomer and author Bob BermanWho hasn’t heard the old question, “If a tree falls in the forest, and nobody is there, does it make a sound?” If we conduct a quick survey of friends and family, we shall find that the vast majority answer in the affirmative. By taking this stance, people are actually averring a belief in an independent universe that exists just as well without us as with us. This fits in tidily with the Western view held at least since Biblical times, that “little me” is of small consequence in the cosmos.

But look closer. Sound is a disturbance in some medium, usually air, and a tumbling tree produces air-pressure variations. Tiny, rapid, puffs of wind. There is no sound attached to them. If a person is nearby, the puffs physically cause her ear’s tympanic membrane to vibrate, which then stimulates nerves only if the air is pulsing between 20 and 20,000 times a second – with an upper limit more like 10,000 for people over 40, and even less for those of us whose misspent youth included earsplitting rock concerts.

Nerves stimulated by the moving eardrum send electrical signals to a section of the brain, resulting in the cognition of a noise. This experience, then, is symbiotic. The pulses of air by themselves do not constitute any sort of sound. The ear’s neural architecture and a brain conjure the noise experience, and are every bit as necessary for sound as are the air pulses. In other words, the external world and human consciousness are correlative.

When someone dismissively answers, “Of course a tree makes a sound if no one’s nearby” they are merely demonstrating their inability to ponder an event nobody attended. They’re finding it too difficult to take themselves out of the equation. They somehow continue to imagine themselves present when they are absent.

Now consider a lit candle. The flame is a hot gas that emits photons — tiny packets of electromagnetic energy waves. Each consists of electrical and magnetic pulses. Neither electricity nor magnetism have visual properties. So there is nothing inherently visual, nothing bright or colored about a candle flame. But if these same invisible electromagnetic waves strike a human retina, and if the waves happen to each measure between 400 and 700 nanometers from crest to crest, then their energy is just right to deliver a stimulus to the eight million cone-shaped cells in the retina. Each in turn sends an electrical pulse to a neighbor neuron at 250 mph until it reaches the warm, wet, occipital lobe of the brain, in the back of the head. There, a cascading complex of neurons fire from the incoming stimuli, and we subjectively perceive this experience as a yellow brightness occurring in a place we have been conditioned to call “the external world.”

So there isn’t a “bright yellow” light “out there” at all. At most, there are invisible electrical and magnetic pulses. WE are totally necessary for the experience of a yellow flame. Again it’s correlative.

Consider rainbows. This one’s easy, since it’s obvious that we are absolutely necessary for a rainbow’s existence. When nobody’s there, there simply is no rainbow. (Rainbows have such a low intrinsic reality, they don’t even cast reflections). Three components are necessary for a rainbow. There must be sun, there must be raindrops, and there must be a conscious eye (or its surrogate film) at the correct geometric location.

A person next to you will complete their own 42° geometry from the sun’s anti-solar point, and will be at the apex of a cone for an entirely different set of rain drops, and will therefore see a separate rainbow which needn’t even look like yours. If the sunlit droplets are nearby, as from a lawn sprinkler, your companion may not see a rainbow at all. Your rainbow is yours alone. But now we get to our point: what if no one’s there? Answer: No rainbow. An eye-brain system must be present to complete the geometry. A rainbow requires your presence just as much as it requires sun and rain.

Few would dispute the subjective nature of rainbows, which figure so prominently in fairytales that they seem only marginally to belong to our world in the first place. It is when we fully grasp that the sight of a skyscraper is just as dependent on the observer, that we have made the first required leap to understanding the nature of things.

The above is taken from a chapter in my new book, co-authored with Robert Lanza, MD, Biocentrism, published next month.

Just a Coincidence?

Posted Feb. 10, 2009 – It’s easy to be confused about coincidences. If lightning strikes the church just as aunt Betty dies, most of us would connect the two events. Some folks even claim that everything is intimately linked. But this morning while you brushed your teeth, and a tree crashed to the ground in Yellowstone Park, would you really say the two events are connected?

Eliptical galaxyCoincidences are bothersome to scientists. Take the Andromeda galaxy, straight overhead at midnight. That this nearest of all spiral galaxies is also the biggest and brightest within 35 million lightyears is strange. But there Andromeda sits, and that’s how it is.

Or consider that our sky has just two disks, sun and moon, that both appear the same size. This alone brings about those amazing total eclipses. And we have a north star that just happens to be the brightest and most precisely aligned of the past 26,000 years.

Far more typical than such true coincidences are the logical match-ups. People are often amazed that the moon spins in the same period in which it revolves around Earth, keeping the same hemisphere forever pointed our way. But tidal stresses always slow a satellite’s rotation until it’s locked in place. Every moon of every planet has this same synchronous spin. What about the fact that the strong nuclear force, gravity, and 20 other parameters are just perfect for the formation of life? Another coincidence?

Here the Anthropic Principle is invoked: Only in our kind of universe would stars, planets and sentient beings have had time to form. If things weren’t this way, we wouldn’t be around to wonder about it, but since we do and here we are, then the universe had to be this way. Yogi Berra would be proud of this reasoning, but it’s now generally accepted.

It’s sometimes hard to separate coincidence from correspondence. Take the 11-year sunspot cycle. Powerful solar storms must do something to us. But only some two dozen sun-cycles have been observed, against which we can hunt for thousands of potential rhythms from political events to climate changes to earthquakes. Which are related and which are merely the mischief wrought by the law of averages?

Checking back we find that the solar cycle swings in harmony with the fashionable length of women’s skirts, the rabbit population of Australia, the party that controls Congress, the position of the Gulf Stream, and the thickness of Earth’s atmosphere. Only those last two are probably related to the sun.

But you see the problem. Or do you?