It took enormous resources and people willing to work long hours and take some big risks. The Moon landings were a result of the Cold War. It became a competition to see who could build the biggest number of history’s deadliest rockets. Along with that was a push to gain the ultimate high ground – space. The Moon became the highest of the high. The United States mobilized a tremendous corps of workers, built big rockets, and got it done. The Soviet Union went out of business about twenty years later. But despite the politics, it was the most exciting thing ever.

For many days after the successful landing and return of the Apollo 11 crew, everyone on Earth shared that spirit of excitement. After twelve people landed on the Moon and returned safely to Earth, interest in expensive journeys to visit the “magnificent desolation” of the Moon waned. Instead, we have sent well over 100 spacecraft there to learn more of the Moon’s makeup and its past, which you have to figure, is our planet’s past as well.

Spaceflight around the Earth, in what’s called “Low Earth Orbit” (LEO) has become routine. More than 500 people have flown in space. We at the Planetary Society (planetary.org) are hoping humankind sets out on new space journeys to new hardly-known places in space. There are asteroids headed our way. There is a great deal to be learned from the climate of Venus. And, who knows? Life on Earth may have gotten started on Mars. Wouldn’t it be something to go there and have a look around?

So, take a moment this week and reflect on how far we’ve come as a species and how much we don’t know about our planetary home. Our relationship to our Earth, our Moon, and our neighboring planets helps us understand how very special the Earth is. The people who helped humankind land on the Moon 41 years ago were explorers. Their adventures and the discoveries they made changed the world for all of us. This week, let’s celebrate our place in space.

This week, I was asked to comment on the big heat wave along the east coast of North America and the resolution of the scandal that came to be called “Climategate.” Along with these serious subjects, an egg got fried on a sidewalk.

As you may know, I strongly believe humans are making our world warm. The egg on the sidewalk provided me with a chance to talk about the fundamentals of heat transfer and about our changing climate.

I commented briefly that indeed Climategate was much ado about very little. The scientists were proven to not be hiding anything, and so on. Unfortunately it nearly derailed the real climate conference in Copenhagen. Several minutes later at the end of her show, journalist Campbell Brown showed some video of one of her CNN producers taking a shot at cooking an egg on a New York sidewalk.  He had a bit of trouble, but I think he got the idea across. It’s hot back east, very hot.

Using my radiant thermometer (pyrometer, such a word!), I satisfied myself that an egg on a griddle cooks well if the griddle is around 125 Celsius (260 Fahrenheit). Doing a bit more messing around, I found that an egg will cook on a surface that’s only 55 Celsius (130 Fahrenheit). It just takes time – almost 20 minutes. So indeed, it can be hot enough to fry an egg on the sidewalk.

The little hand-held radiant thermometer is upside down, but it shows around 53.8 Celsius. This took about 22 minutes to cook under ideal cast iron skillet sidewalk temperatures. Along with the temperature, we need the pavement to hold a lot of heat (high thermal capacity). Sometimes the sidewalk isn't hot enough through and through; it depends on the pavement. Sure; try it...

I can tell you from experience in the airplane electronics industry that you can, for just a moment, put your hand on a metal surface that’s around 65 Celsius, about 150 Fahrenheit. Much above that, and you can’t leave your hand there for more than an instant. You may have found yourself walking on a hot sidewalk or on hot sand, and you can just barely stand it (pun intended). That’s the temperature we’re talking about.

If you want to try this, please do. Post a picture on my Facebook page. Some more advice: use a little olive oil or butter on the sidewalk or street. This allows more heat to flow into the egg. This is “conduction” of heat. Then, use an egg “ring” to keep things under control while the egg gets hot. You get your egg rings (if you don’t already have ‘em) in the gadget section of a grocery store or cooking specialty shop.

The science to discover or keep in mind is that the sidewalk can get hotter, much hotter, than the air. The air this week was around 40 C (a little over 100 F). But the egg cooking area was a bit hotter than that because it’s not only heated by the air, it’s heated by sunlight, or sun-heat. It was heated by convection with the air, and by radiation of the sun. Black surfaces do indeed get hotter than not-so-dark surfaces. Asphalt gets hotter than cement. Hot enough to fry an egg. Oil helps conduct heat into the egg.

For me, this has everything to do with climate change. Everyone should keep in mind that if we made every black street a pale color, like white, or close to white, the world would indeed cool off. If we did indeed embrace solar hotwater systems for our houses and buildings, we would pump out much smaller amounts of greenhouse gasses.

If you’re a young or young-at-heart engineer or entrepreneur, consider coming up with an economical pale pavement material and getting rich! Same with a standardized solar hot water system. Rich! I tell you!

Two more good ideas. Think about it over fried egg, your poached egg, your egg salad sandwich, and your soufflé.

Let’s change the world,

Bill

Visit msnbc.com for breaking news, world news, and news about the economy

One day, as a very young man, around age seven, my older brother Darby patiently wound the rubber band “motor” on a newly purchased Skystreak balsawood airplane, and handed the aircraft to me.

Having flown various glider airplanes for weeks that summer, we had chanced on the idea of bending the vertical tail to provide a little steering– some yaw control.

I carefully held the plane up near my right ear, one hand on the balsa stick that serves as the fuselage, and one hand securing the propeller. I let fly. The little Skystreak flew like none of us had ever seen. It climbed, while making three graceful circles in the sky. It descended and returned to me as if it were a storybook boomerang– right to my hand. I had produced controlled flight. I was hooked.  I wanted to be an engineer.

Long about that same time, my father set up a musty telescope, given to him by his old scoutmaster. I saw craters on the Moon. My dad, by the way, had spent almost four years as a prisoner of war in Asia. He had seen spectacular dark skies. He knew his way around the heavens. So some days later, we saw the rings of Saturn.

Now, many of us have had similar experiences with stargazing, microscope gazing, or watching a dandelion’s life cycle. But through what I consider remarkable luck, I ended up in Professor Carl Sagan’s astronomy class. He showed us subtle mathematical features of the sky that I had only suspected but never known. He emphasized critical thinking and the scientific method– reasoning.

Carl Sagan wrote the novel Contact that became the movie Contact. He won a Pulitzer Prize for his book Dragons of Eden.

Along the way, concerned about NASA’s flagging interest in space exploration with the public’s interest as strong as ever, Professor Sagan, Dr. Bruce Murray, and Dr. Lou Friedman set up the Planetary Society. It became the world’s largest non-governmental space interest organization.

Well now, my friends, after 30 years on the job, Lou is retiring, and I am to become the Planetary Society’s Executive Director.

What an opportunity, a chance to change the world! We are at another turning point in the history of space exploration. The United States’ Space Shuttle program is finally winding down. Over 100 spacecraft have visited the Moon. Dozens of other space missions from space agencies around the world have proven that Mars was once a very wet place. It’s time to look there for signs of liquid water and evidence of ancient or even extant life. By looking back into the fossil record of deep time, we have a new awareness of how much trouble a speeding space rock could cause. It’s another moment in history, where we must learn more about our place in space. It’s another opportunity for ordinary people to share in the exploration of a new frontier, to go beyond the unknown horizon. What a ride!

Since I launched my first model rockets, I’ve loved space exploration. I hope you’ll take a few moments and learn about the Planetary Society. It’s quite a group.

Meanwhile, I will keep on posting my commentaries on science, technology, education, and especially climate change. We’ll see if we can change the world.

Thanks for your support,

Bill Nye

Check out http://Planetary.org

I have mentioned Professor Phelan often to my engineering colleagues, and well, to anyone who’ll listen. He specialized in a niche area of mechanical or electrical engineering generally called “control theory.”

Professor Phelan realized that the way most engineers and scientists go about controlling things like the temperature of an oven or a house– a thermostat, or the speed of a car– cruise control, is not nearly as good as it could be. And the reason is elegant and mathematically simple.

Thanks for reading this far, if you did. I will go on about Dick’s big idea in the next few paragraphs. I hope you get that he had an idea that could change the world and allow us to do so much more with less. Richard Phelan meant a lot to me.

****

Dick Phelan and Pseudo Derivative Feedback (PDF)

If you’re into this kind of thing, you know that most controllers work best with an integrator in the forward loop. For most of us, the classic example is sticking your hand in the shower to get a signal (hot, cold, cool, or warm) that your nerves, brain, and muscles use to set it just right. You adjust a faucet knob and wait. Your brain integrates the signal; you subtract what you feel from a suitable proportion or fraction of what you want, and eventually–  Ahh…

An old trick, and a seemingly reasonable one, is to put a differentiator in the feedback loop. That way, the feedback signal gets stronger (uh, bigger), with not just the change, but with the rate of change. All good.

The scheme I described above is Proportional+Integral+ Derivative (PID) control. It is everywhere. I mean everywhere. Even the most sophisticated satellite attitude controller systems are PID. Oh yes, one can analyze the Laplace Transform heck out of those things, what with their spindly struts and drilled-out, mass-saving, trusses, busses, and brackets. But, when it comes down to it, often, very often, our colleagues abandon all the extra analysis and just optimize a few PID variables.

Here’s what Dick Phelan realized, pointed out, and fixed. With PID, we’re integrating a signal we just differentiated. Any transducer noise or vibration often makes the feedback signal too big, or just wacky.

Instead of PID, try this: Feedback a signal in two places. On a control diagram, it’s two summing junctions. Feed the signal back upstream of the integrator, and then, with a separate proportionality constant, downstream of the integrator. The signal downstream of the integrator acts as though we differentiated. But, there is no, or much less, noise.

Dick called his scheme Pseudo Derivative Feedback, or PDF. I’ve seen others refer to the same thing with an I in front of the acronym to indicate integration. That’s not bad, but in tribute to Professor Phelan, I prefer PDF.

Now, Dick Phelan was a bit of character. Although one of his earlier textbooks gives the reader a solid understanding of Laplace transforms, later in life, he didn’t think much of them. Consider these words from his textbook: Feedback and Control Systems, Cornell University Press, 1977:

“The apparent justifications for past use of Laplace transforms were (a) it was a good way to keep students occupied in an intellectually stimulating way for quite a period of time, and (b) it established a jargon for the fraternity while effectively sophisticating– in the true dictionary definition of the word– a basically simple field of study into one that was awe-inspiring to the unknowing…”

Well, control theory can get complicated, but it’s the key to our future. We have to find ways to not just use less, as traditional environmentalists wanted us to do. Instead we have to find ways to be more efficient, much more efficient. We need to find ways to do more with less. PDF will help us engineers and designers do that. Thanks Professor Phelan. Let’s change the world.