Tag Archives: universe

P-0 days: Navigating Pluto

Where are we?

Pluto!

Closest approach was at 7:49 AM this Tuesday morning, July 14th in Baltimore. Pluto—12,500 kilometers away—was about 22 times the size of the Moon seen by the naked eye. Image mosaics are underway. The next event, occultations of the Sun and Earth by Pluto, begins at 8:45. After that, the same occultations by Charon begin at 10:15.

Of course, we have no way of knowing any of these things really happened until information travels at the leisurely speed of light for 4 hours and 25 minutes to get to Earth. Unfortunately, at this red-hot moment, the spacecraft is too busy with pictures and other observations to turn the antenna towards us to send that information. We have to wait until later this evening when the antenna centers on Earth and sends a radio postcard.

Where are we going?

The outer environs of the solar system, deeper into the Kuiper Belt for another encounter with one of a couple of recently discovered heavenly bodies (if NASA approves a mission extension), thence to the Oort Cloud and onward into the Milky Way.

Where are we from?

Earth
Solar System
Milky Way Galaxy
Universe, Zip 18395782886253402871-981294673.23

This is my last post of the Navigation countdown. We’re seeing Pluto up close and personal—we hope, unless the spacecraft has run into a piece of random debris, in which case we’ll never hear from it again and all those pictures will be lost. We’ll know for sure tonight.

Pluto. Been there, done that. Remember, this is about the voyage, not the destination. We Navigators almost always get you there, and in this case we most definitely got you there, whether the spacecraft is healthy and intact or in tatters. Onward to the next body. Onward with the next mission, to the next dream hatching in our restless souls. It is a never-ending journey.

What’s the point of this exploration? Will any of us ever live on any of these new worlds we’ve paid lots of money to get to? I think not. I think that the era of solar and extra-solar settlement is far beyond the horizon of our lifetimes. We have a lot of wars to fight and disasters to recover from before our evolved descendants ever colonize another world in this solar system or beyond. It will happen, but not soon, not until we’ve evolved the mean-streak and stupidity out of ourselves.

Will we wipe ourselves out? No. The human race is hardy and some will survive the worst disasters, be it nuclear war, devastating climate change, or a random asteroid strike. Some will survive and begin the climb back to civilization and the next disaster, just as it happens in Walter Miller’s A Canticle for Leibowitz. Read that book if you want a chilling yet poignant depiction of our future. Science fiction writers are the long-term Navigators of our species.

My message, if it’s not clear, is that we have little need to be optimistic in the short run—I think we’ll have a series of disasters and recoveries—but the future is very bright indeed over the long haul of centuries, millennia, or even millions of years. After all, we’ve only been around as a species for a couple of million years on Earth; think what we’ll be like in a couple more!

Meanwhile, life presses on, full of struggle and despair but sometimes with a glimmer of hope on the horizon. The hope is that we learn a little more today than we knew yesterday. The hope is the beginning of the next adventure. Onward to the Kuiper Belt and the outermost reaches of our solar system.

Why go? I think I said it best myself as Voyager finished Neptune a long time ago and headed out toward the deeps of the galaxy. The very fact of her improbable existence cruising among the stars for billions of years to come say this to any potential finders:

I am from the planet Earth. I am of the Human Race. We are small and insignificant but our souls are large because we have set out on a journey to know the Universe.

150716_SignedBplane

Review: The Fabric of the Cosmos by Brian Greene

22435If you’re curious about the universe, if you always had a hankering to understand relativity, quantum mechanics, string theory, M-theory, and how many supersymmetric particles can dance on the head of a pin, one of the ways to make a little progress on your never-ending journey of understanding reality is to read Brian Greene’s The Fabric of the Cosmos: Space, Time, and the Texture of Reality.

He begins with a spinning bucket of water to illustrate the notions of motion held by Newton, Leibniz, Ernst Mach, and Einstein in their conflicting views of absolute versus relative space. For a couple of chapters and most of a hundred pages he threads the ideas of those thinkers through that simple spinning bucket and concludes unsurprisingly that Einstein has the best handle on the issue with his general relativity theory supporting a surprisingly absolute concept of spacetime and accelerated motion. And Greene manages this while not putting you to sleep, keeping you entertained with intuitive analogs and earthy examples such as a pistol duel between two whimsically named characters, Itchy and Scratchy.

Although my educational background is physics (from a long time ago), I learned something new—an astounding revelation for me in a chapter devoted to quantum theory. To the counter-expectations of Einstein and many others, physics (aka nature and reality) was proven to be non-local as a result of experiments in the 1970s and 1980s based on an insight by physicist John Bell in 1964. This earth-shaking result, violating the cherished notion of the locality of physics, establishes that things can be interconnected instantaneously at a distance, sinking Einstein’s notions of hidden variables and the incompleteness of quantum mechanics. The experimental establishment of quantum entanglement and the discovery that it apparently disobeys the law—the speed limit of light—nearly brought down the Special Theory of Relativity, leaving it in a delicate and unsteady balance with quantum theory.

The book progresses through three more broad themes—“Time and Experience,” “Spacetime and Cosmology,” “Origins and Unification”—before concluding with a final “Reality and Imagination.” The topics within those themes include the ebb and flow of time and its dance with entropy (which way does time’s arrow point?), the teeming fullness of the cosmic vacuum, the Higgs field and the Big Bang, repulsive gravity, inflation and a runaway universe, string theory and M-theory, and curled-up six-dimensional Calabi-Yau shapes in ten-dimensional spacetime.

As might be expected, the last theme, “Reality and Imagination,” is full of blue sky (or should that be black sky?) conjectures on dark matter, dark energy, and the fate of the universe among other things, but among those other things is discussed the concrete and tantalizing possibility that strings (the fundamental constituents of string theory whose different vibrational modes constitute everything we’re made of) might be much larger than previously thought, which would translate into the CERN Large Hadron Collider finding scads and scads of previously unseen supersymmetric particles, like ”a well-hit golf ball ricocheting around the inside of a piano.” The book was written in 2004, and since then the first phase of collider operations has concluded with the discovery of the Higgs particle but not much else. Although this is not a refutation of string theory, it puts a damper on some aspects of it that Greene waxes enthusiastically about. There remains a chance that the future upgraded version of the collider will find something in its extended energy range.

This book manages to make an entertaining story out of an incredibly esoteric and still unsettled field. Greene is a master of the simple and easily grasped analogy, which is why his explanations are so easy to follow and understand. He more than acknowledges the incompleteness of our knowledge of the cosmos, and in fact revels in its incompleteness as an exciting path forward through a jungle of unknowns, a never-ending path of adventure for the human spirit. If you’re curious about the cosmos and the meaning of space and time, then The Fabric of the Cosmos is your book. It does a damn good job of laying out some of the answers and being entertaining as well, but leaves plenty more unknowns to ponder …

But then that’s the nature of the infinite journey we’re on, isn’t it?

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Voyager at Neptune

This OpEd ran in the Sunday L. A. Times, 1989/08/06

Neptune! Almost 3 billion miles from earth. It’s a cold, impersonal place, a speck of a planet through even the largest telescope, but an enormous gas giant full of mysterious wonders when seen up close.

In a few more weeks we’re going to experience it up close, you and I. We will see it through the eyes of a solar diplomat: a traveler, explorer, adventurer, and representative of the human race; a large metal, plastic, silicon representative named Voyager.

When we arrive, what should we expect? The unexpected! That’s the lesson learned from previous visits to unexplored planets. Are there rings at Neptune like those at Jupiter, Saturn and Uranus? Possibly, but in incomplete arcs, unlike rings anywhere else. Are there other satellites, besides the already known Triton and Nereid? Yes! One has already been discovered, and there’s tantalizing evidence of more—perhaps many more, maybe even clouds of them — lurking just beneath the fuzz in the images painting the screens of video terminals at the Jet Propulsion Laboratory. In just days, now, they could rise to visibility above the electronic background noise.

Neptune has its own internal heat source, and radiates more energy than it receives from the sun. Why? Is this what drives its turbulent atmosphere, generating the large spots already found? Soon, we may know.

And Triton? We’ll find whether it has an atmosphere, and whether we can see through to the surface. Will there be pools of liquid nitrogen, or will gasses be frozen in slabs littering a desolate landscape of craters and mountains?

Among the answers to the questions we know to ask will be more questions we’ve not imagined—the unexpected!

When Voyager arrives at Neptune—on August 25th—it will be the first time since creation that anything human-made has been to that planet. We should enjoy, appreciate, and celebrate the event, since it will also likely be the last time it will happen during our lives.

That’s because a very special arrangement of the solar system, one that occurs only about every 175 years, was required to allow Voyager to make the trip in “only” twelve years. It had to go by Jupiter first, making a hard left turn in that planet’s gravity to pick up energy in a crack-the-whip fashion to go on to the next planet. That was Saturn, which turned it left again, gave it more energy, and pointed it towards Uranus. At Uranus, in 1986, it picked up still more energy and made course for Neptune. Since then it has been “cruising” at ten miles per second toward the planet. At Neptune it will skim over the north pole three thousand miles above the atmosphere, turn downward so that it’s headed south out of the solar system, and make a final encounter with Neptune’s largest satellite, Triton, before beginning a larger interstellar voyage.

The science at Neptune is important, but think also about the voyage, the adventure. Knowledge is good for the human mind, but travel is food for the psyche. And Voyager’s travels have been and will be prodigious. It has been on its way from earth since 1977, wending a crooked path through the outer solar system. Now, in a handful of days, it makes its final rendezvous, a close brush and embrace with Neptune, before flying out of the solar system to begin an odyssey through the Milky Way galaxy; an unattended, lonely voyage that may last from millions to billions of years.

Towards the beginning of that longer journey, a mere few hundred thousand years in the future, our sun will have become a faint, uninteresting star in Voyager’s eternally night sky. But no one will be with the spacecraft to appreciate that fact, and our ambassador will slowly tumble—sightless, senseless, and alone —in an immensely empty void.

A fellow engineer on the navigation team claims that the spacecraft will be on display in the Smithsonian Museum 200 years from now. He thinks that by then we’ll have both the technology and wherewithal to go out, find and catch Voyager, and bring it back. I’d like to think we would be able to do that, but if I’m still around I’ll vote to leave it alone. There’s something wonderful about the thought that a piece of ourselves is somewhere out there on a winding journey between the stars on its way to eternity. It’s like having immortal children.

So this is an adventure, and we’re all on board. The solar system is our playground, and after that—the stars! There are hazards ahead—for example, unseen ring particles orbiting Neptune could smack into us, prematurely ending Voyager’s life—but we’ll probably make it through to see the wonders of Neptune and Triton.

Then will begin the grander voyage—the one that requires us to be romantics instead of realists; dreamers rather than schemers: Even though Voyager will go blind and deaf after a few tens of years; even though it will die an electronic death, it will still have the germ of human creativity and daring incorporated into its very structure. It carries two messages—an explicit one in the form of a golden record, and an implicit one stated by its profoundly improbable existence. And both messages will say to the finder, in essence, “I am from the planet earth. I am of the human race. We are small and insignificant, but our souls are large because we have set out on a journey to know the universe.”

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