If you’re not familiar with this observatory, it was featured in the movie Contact. It’s ideally suited for receiving signals from deep space and even for transmitting our signals out into the void. It was designed to explore the cosmos and our own ionosphere. Conceived in 1958, built by 1963, it’s been upgraded and refined in the decades since.

The premise of the bit (as we say in comedy writing) was to build a telescope so big that it could and can detect electromagnetic signals at astonishingly low energy levels. These would be signals emanating from high in our own atmosphere as well as from fantastic astronomical distances. The reflector of this machine is too big to move. It fills a whole valley– an ancient sinkhole actually, a bowl created by the collapsed roof of an ancient underground limestone cave. The valley has been fitted with a reflective section of a sphere 1000 feet (305 meters) across that’s round to within plus-or-minus 1.5 millimeters (1/16^th of an inch). It’s got 38,778 panels of perforated aluminum sheet, each very much resembling the metal screen in your microwave oven door. The whole installation is amazing in its construction. But for me, the more amazing aspect of the machine is the conception, the idea that humans could build such a thing— and have it work.

The receivers above the reflector are suspended on an almost crazy system of wire ropes (the engineer’s term for steel cables) and pulleys. The receiving and broadcasting antennae for this thing are enormous. They appear to be suited for some Jolly Silver Giant, were he to exist, who loved radio astronomy (?!). You’ve probably seen radar dishes and TV receiver antennas that have a curved shape called a parabola. It’s the shape that you get when you draw a curve that’s equally distant from a flat plate and a point above it or near it. With parabolic antennae, the incoming rays of light or radio waves bounce to that point; we call it the focus. At Arecibo, with a sphere for a reflector, rather than focusing to a point, shape focuses to a line. So, the antenna is a stick… 25 meters long. Also there at Arecibo, there’s a second system of scoop shapes that form a detector big enough for a family of four to camp out in comfortably. It’s crazy.

This machine not only receives deep space waves; it can create them. In a separate building, we have a microwave-making klystron, a cavity that can store microwaves just long enough for them to build up, to constructively interfere with themselves. The energy goes flying out of the klystron at the speed of light. High above the big dish are two other klystrons in tandem. They’re just like the one in your microwave oven; only these reckon their power in Megawatts. Radar signals can travel to 100-kilometer-diameter asteroids, millions of kilometers away, and record surface features just a few meters across— all in less than a second. When investigating Saturn, the astronomers have to plan for the Earth rotating as they wait the hour and a half for the electromagnetic waves to make the trip there and back. Instead of regular wires, microwaves have to travel in hollow conductors, often made of very pure metals. By long tradition, we call them “wave-guides.” The microwave signals at Arecibo travel through 1600 feet of perfectly machined square wave-guide tubing. The hollow guide’s joints and interfaces transmit microwaves, like in your oven, only these go into deep space with barely 3% of loss.

The whole machine with its accompanying instruments and its dedicated staff is audacious. It’s the work of a citizenry dedicated to exploration and learning more of our place in space. It is the product of the best use of our intellect and treasure. If you have a chance, consider a trip there sometime. O there are many worlds out there. To learn about them, try a trip around ours.

Bill Nye

Each presenter I spoke with is excited to be exploring Venus but generally suffering a little frustration. Imagine us, a spacefaring species that loves to wander and transmit images, relishing pictures of exotic lakes of ethane on a moon of distant Saturn, but not knowing if a planet much closer by, that shines romantic beams every evening brighter than any star, has volcanoes erupting on its surface. Venus is a hard target– solid rock but a very difficult place to explore. It’s clouds of sulfur compounds obscure a rocky surface so hot that the acid rain evaporates before it can get to the ground.

After a few papers were presented, it became clear to anyone in the audience, that all of us should be thinking hard about Venus and what goes on there– especially what goes on with its weather– its climate. It’s the greenhouse effect gone wild.

Whether the researchers were arguing about the isotopic evidence for and against volcanism, or whether they were brainstorming ways to get balloon gondolas to survive a whirlwind trip in the relatively warm though low pH super-rotation of acidic winds aloft, they all share a concern about Earth on account of their fascination with Venus. The subtext of all the Venus talk is climate change on Earth.

Looking at a first cut of the venusian data, Venus is our sister planet. It’s rocky, round, and about the same size as our Earth. It has fluffy white clouds. Although it’s just 30% closer to the Sun than we are, it is hellishly hot, and no sky can be seen from its surface. Its rotation has been slowed to once every 240 Earth days by the astonishing tidal drag of it’s 90 Bar atmospheric pressure. In that dense gas mixture, the clouds spin around ten times faster than the planet they hide. For these researchers, it’s the atmosphere that’s brought all these striking inhospitable features to the fore of the VEXAG discussions.

Almost every paper presented carries with it concern about climate change back here on Earth. Using data gathered by Soviet spacecraft over 20 years ago, researchers are looking for evidence of lightning. Japanese scientists and spacecraft builders have Akatsuki en route to our clouded sister world. Named “Dawn,” because that’s when Venus is visible, it will fly into a brilliantly conceived orbit that will allow studies of the Venusian air, with light from both the planet’s limb and cloud decks. Along with managing the passage of night and day, Akatsuki is in, not a surface-synchronized orbit, but a super-rotating cloud-synched route. And of course, European and North American explorers continually plan missions to know more about this hot old place.

Sanjay Limaye from the University of Wisconsin, an old friend of the Society and the organizer of the event, arranged for a public talk. Several hundred people came to hear about Venus. Jan Smit from the University of Amsterdam spoke about the geologic boundary created by the Chixalub impact 65 million years ago. He showed that it is indeed the event that wiped out most of the ancient dinosaurs. He logically tied that mass extinction to climate changes on Earth, and then to climate change on Venus. David Grinspoon from the Denver Museum of Nature & Science was next, showing the audience the clear connections and lessons to be learned from the geology of Mars, Earth, and Venus. Climate change was once again his focus. Finally, I got up and did my best to entreat the crowd to take climate change seriously and develop new technologies and save the Earth– save it for us, for us humans.

For me, VEXAG was remarkable. Venus is our closest neighbor, yet we are not clear on what makes that world go round. Everyone at VEXAG would agree, we have to come up with many more missions and methods worthy of the challenge above and beneath the clouds of Venus.

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.

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’m in the picture along with the board of the Planetary Society. We’re working to change the world. I hope you are too…

]]> http://www.billnye.com/in-honor-of-stephen-hawking/feed/ 2 http://www.billnye.com/plutonium-in-space/ http://www.billnye.com/plutonium-in-space/#comments Thu, 12 Nov 2009 17:31:37 +0000 Bill Nye http://www.billnye.com/newsite/?p=155 Read More > ]]> About fifteen years ago, I had the honor and pleasure of having lunch with Glenn Seaborg. Unlike many of us, he was awarded a Nobel Prize. He discovered, or created, or contrived the means to prepare the very first piece of Plutonium humans had ever seen. He was of the Nuclear Age, a time when it was imagined that nuclear power would render electricity too cheap to even bother charging customers for.

Plutonium is not only fantastically dangerous on account of it being radioactive, but it’s also remarkably toxic. Glenn Seaborg told me that inhaling a milligram would kill a person in seconds – this over lunch. Glenn (by this point in the lunch, I called him Glenn), also told us that “they” (his colleagues) wanted him to call it Plutinum [PLOO-tih-Numm]. Then he said, but, let’s face it Bill (calling me Bill, very fine with me), Plutonium [Ploo-TOE-Nee-umm] sounds a lot cooler [KOO-ler]. He emphasized that he insisted, back in the day, that this newly discovered metal’s atomic symbol be Pu, [pee-Yew]. He wanted, he said, to emphasize that Plutonium “stinks.”

You make it by transmuting Uranium two-thirty-eight (238), which has 92 protons and 146 neutrons into Plutonium 238, which has 94 protons and 144 neutrons – simple enough(?!). At any rate, after you use a nuclear reactor, maybe with some Neptunium and just the right geometry, your Plutonium is strikingly energetic. That’s why the U.S. Department of Energy finds the bombs made with Plutonium so, well, energetic, as well.

This would be just another astonishing example of a few humans, through astonishing diligence, discovering another astonishing secret of the Universe. But for all of us, there’s even a little more to it.

Plutonium is what we use to know our place in the Universe. Plutonium is not only good for bombs; it’s what we use to make electricity on spacecraft. These electrical gizmos (gizmoes?) use the heat produced by radioactive compacted Plutonium to drive electrons from one piece of metal to another not-quite-the-same (dissimilar) metal. And, these radioactively heated coupled metals make electricity- for 30 years running. We call them Radio-Thermometric Generators (RTG’s).

The U.S. Government, Congress, the President, et al have decided that Plutonium is so stinky that we don’t need any of it anymore. Owing to its inherent dangerous quality, that might seem like a good idea. But, we in the United States, our Earth’s leader in interplanetary exploration, will no longer be able to explore a planet beyond Mars. See, the thing-of-it is that there is not enough sunlight out there. Out where Jupiter, Saturn, Uranus, Neptune, and the Plutoids are, sunlight is so spread out that we cannot power our electronics. Oh, you can hope for some kooky and fabulous new innovations to make distant space ships continue to sail. But really people, the problem is too hard, much too hard. We need some, a very small amount indeed, of Plutonium.

So, maybe next time around voters and taxpayers can help their representatives see the light, or the heat, of Plutonium – just a little.

For now though, we’re going to have to count on our telescopes and the dozen or so spacecraft that still carry RTG’s. This would include the next Mars rover, the Mars Science Laboratory (MSL) that, unlike the Spirit & Opportunity rovers will be able to work hard all winter there. New Horizons, the Pluto mission would be dark and cold as well as being out in the dark and cold. And Jupiter? Saturn? Without their RTG’s we would have no shadows on rings. We would know nothing of storms in a gas giant. The fuel of an RTG is dangerous, but these craft let us make amazing discoveries and help us address the two questions that drive us all. Where did we come from, and are we alone??

Here’s hoping, in the next few years, we decide to spend $30 million it would take to keep the outer planets within reach.

Copyright Bill Nye

Solar Sails

Among other things, I’m the vice president of a worldwide, medium-sized organization called The Planetary Society. We are launching a series of spacecraft that will be driven through space, not by rocket fuel, but by the pressure of sunlight.

It is surprising at first, at least for most everyone I’ve ever met, that light has momentum. Light has no mass, y’know. Yet it can ever-so-slightly push things.

You probably know or accept that E = mc². This is to say that if you could convert all the mass in a bit of matter, say the hydrogen in a glowing star, into pure energy, you’d get an enormous amount of it. A kilogram of mass times 300,000 kilometers per second (186,000 miles per hour, as was said back in the 20th Century) is an enormous number of sustained Watts (Watt-seconds or Joules, okay, or foot-pounds).

Well, if you mess around with this equation and insert the idea that moving energy kinetic energy would carry with it a mass and a speed-squared, you can convince yourself that light has momentum. The theoretical limit being established by a physical measurement called Plank’s Constant.

So, we at the Planetary Society are building three very, very low mass sails, solar sails spacecraft. Our solar sail will be pushed through space by the momentum inherent in photons, particles of light, in this case those beaming from our Sun. A photon carries a quantum of energy, the smallest packet of energy we can measure. But with quadrillions of them impacting the sail at every moment, we’ll get a tiny shove. Since the light beams continuously, we hope to build up speed. By the time we build the third sail we hope to have gotten a nice orbit going.

It’s going to be fantastic the first new propulsion system since, well, since the Greek mathematician Heron built his steam jet reaction spinner engine.

We can sail by starlight. How cool is that?