The Science of Star Wars: An Astrophysicist's Independent Examination of Space Travel, Aliens, Planets, and Robots as Portrayed in the Star Wars Films and Books

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Macmillan, May 5, 2000 - Performing Arts - 256 pages
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Former NASA astrophysicist Jeanne Cavelos examines the scientific possibility of the fantastical world of Star Wars. She explains to non-technical readers how the course of science might soon intersect with such fantasies as interstellar travel, robots capable of thought and emotion, habitable alien planets, bizarre intelligent life forms, high-tech weapons and spacecraft, and advanced psychokinetic abilities. She makes complex physics concepts, like quantum mechanics, wormholes, and Einstein's theory of relativity both fascinating and easy to comprehend. The Science of Star Wars does for Star Wars what Lawrence Krauss's bestselling The Physics of Star Trek did for the Star Trek universe.

Cavelos answers questions like:

* How might spaceships like the Millennium Falcon make the exhilarating jump into hyperspace?

* Could a single blast from the Death Star destroy an entire planet?

* How close are we to creating robots that look and act like C-3PO and R2-D2?

* Could light sabers possibly be built, and if so, how would they work?

* Do Star Wars aliens look like "real" aliens might?

* What kind of environment could spawn a Wookie?

* What would living on a desert planet like Tatooine be like?

* Why does Darth Vader require an artificial respirator?

* Can we access a "force" with our minds to move objects and communicate telepathically with each other?


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LibraryThing Review

User Review  - ZoharLaor - LibraryThing

I am not a huge, or even big Star Wars fan (heck, I didn't even like the first one), but I loved this book. A great concept, very well done. I could not put it down. Read full review

Good reading

User Review  - lucor05 -

Good book to read and expand your knowledge. We enjoyed it. It was received in a timely manner. Read full review


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About the author (2000)

Sir, it’s quite possible this asteroid is not entirely stable.
—C-3PO, The Empire Strikes Back
It comes into view as a small, pale dot against the blackness of space. Dim, inconsequential beside the brilliance of a star. Yet for us, it is a safe haven in the endless vacuum of space. Only here, on this fragile bit of rock or others like it, can life develop and survive. It formed billions of years ago, the right elements combining in the right proportions at the right distance from its sun to bring it to dynamic life. Volcanoes breathed out an atmosphere. Life-giving rains fell, the bit of rock evolved.
As it grows closer, the dot gains color and definition. Major features are revealed: rock, water, ice, clouds. Within the atmosphere, that protective, nurturing envelope, more details become apparent. Only on the surface, though, does the unique character of the planet become clear: the shapes and colors of the topography, the peculiar quality of the star’s light scattered through the atmosphere, the composition and scents of the air, the strength of the gravity, the texture of the ground beneath our feet, the bizarre life forms that are another expression of the growth and development of the planet.
We have visited many such balls of life-giving elements. Each landscape is committed to memory. A flat plain of sand broken only by harsh, jagged rocks. A vast, snow-covered waste. A fog-shrouded swamp chattering with life. An ancient forest stretching high into the sky. A planet-sized city of level upon level. Some seem mysterious; others feel almost like home. We’ve seen planets and moons; we’ve even traveled through an asteroid field. Each has unique characteristics. Anakin’s and Luke’s home world, Tatooine, is part of a binary star system. Naboo has a bizarre internal structure. The Ewok moon circles the gas giant Endor.
In Star Wars, we’re swept up in events that take us to a wide array of strange and intriguing planets. They present an exciting picture of the universe as we’d like it to be: filled with exotic yet welcoming worlds. These planets are generally friendly to human life—which is why the human characters have traveled to them. In addition, though, they have indigenous life of their own, in a variety that keeps us surprised and delighted. But how realistic is this view of the universe, based on what we know today? Are Earth-type planets like those we see in Star Wars likely to exist? And will so many of them be home to alien life?
To have a universe like that in Star Wars, the first thing we need is planets, and lots of them. If our solar system is a fluke, and we happen to orbit the only sun in the universe that has planets, then we’ll never be able to pop across the galaxy for some Jedi training, set up a hidden base in another solar system, or get into bar fights with intelligent alien life.
How numerous are planets in our universe? Let’s first look at how planets form, and what ingredients are necessary in their formation. To form rocky planets like Earth, we need heavy elements like iron, carbon, nitrogen, and oxygen. Unfortunately, they are rare. The two lightest elements, hydrogen and helium, currently comprise 99.8 percent of the atoms in the universe. Hydrogen and helium are great for making stars, but not for creating Earthlike planets or complex life-forms. The heavier elements did not even exist at the beginning of the universe, so stars formed in those early days could not have Earthlike planets orbiting them. Since then, however, stars have been steadily producing heavier elements through the nuclear fusion reactions that power their brilliant light.
In fusion, energy is produced when lighter elements are combined to make heavier ones. When a star exhausts its fuel and dies, it releases these heavy elements into space by exploding or by ejecting its outer layers. A supernova explosion, through its incredible energy, creates even more heavy elements.
If the star lives in a massive enough galaxy, like our Milky Way, then these new heavy elements are held within the galaxy by gravity. They combine with other debris into a cloud of gas and dust, and may eventually form into new stars and planets. These new, younger stars can potentially have Earthlike planets, since the heavy elements necessary have been thoughtfully provided by the older generation.
Considering that Star Wars is set “a long time ago,” is it too long ago to allow for Earthlike planets? While the universe formed about fifteen billion years ago, it wasn’t until ten billion years ago that enough heavy elements had been created to form a planet like Earth. Dr. Bruce Jakosky, professor of geology at the Lab for Atmospheric and Space Physics at the University of Colorado at Boulder, concludes that “ ‘A long time ago’ is fine if we’re talking a few billion years, but a dozen billion years—that’s too long ago.” So we’ve narrowed things down . . . a bit.
Once we have the heavy elements required as raw materials, how do the planets actually form? According to current theory, this debris forms a rotating cloud. Just as a ball of pizza dough, when you toss and spin it, will flatten into a thin crust, so the rotating cloud will collapse into a thin, spinning disk of material. This disk is made up of gas, dust, and frozen chemicals. The dense, inner section of the disk coalesces first into a star. At this point the disk looks like a rotating Frisbee with a hole in the center, the star in the middle of the hole. Dr. Jakosky notes that these disks that form the birthplace of planets seem fairly common. “Between one-quarter and one-half of all stars, when they form, seem to leave behind these disks.”
The solid particles in the disk stick together to form large grains of dust. These grains collide with each other and form larger grains, eventually growing into small bodies called planetesimals. A planetesimal may be only a few inches across, or it may be the size of the Moon. Some planetesimals remain small, becoming asteroids or comets. Others, though, as they rotate around the sun, continue to collide and merge with each other, in a sense sweeping up all the material at the same orbital distance from the sun. As a planetesimal collects all the material in a band around the sun, it becomes a planet. The closer the band is to the star, the smaller the band’s circumference is, and so the less material there is to create a planet. That’s why, so the theory goes, smaller planets tend to form closer to stars and larger planets farther away.
In addition to affecting planet size, the distance from the star also affects planetary composition. Closer to the star, the disk is very hot, and only materials with high melting temperatures, like iron and rock, are solid. Thus those elements make up the majority of the planetesimals, and the planets. In our own solar system, the four planets closest to the sun—Mercury, Venus, Earth, and Mars—are made up mainly of dense rock and iron. Farther from the sun, where the temperature is lower, additional materials solidify, such as water, methane, and ammonia, and become part of the core of the outer planets. These larger planets have stronger gravitational fields, and can attract huge amounts of light gases, such as hydrogen, to surround their cores as massive atmospheres. This process creates distant gas giants like Jupiter and Saturn. Jupiter, for example, has a core ten times the mass of Earth, which is impressive, but including its thick hydrogen-helium atmosphere, Jupiter’s mass totals 318 times Earth’s. Each planet, then, is a product of the unique conditions of its formation.
If this theory is true, then planetary formation is a natural part of stellar formation, and there should be a lot of planets out there. Our current theory certainly does a fairly good job of explaining the features we observe in our own solar system. But until recently, we’ve had no other solar systems to test it against.
In the last eight years, however, a string of discoveries has thrown the theory of planetary formation into doubt. Planets seem more common than ever, which supports our theory. Yet the planets we’ve been discovering around other stars are quite different than those our local system led us to expect. Dr. Jakosky explains, “A lot of the planets we’re finding are oddballs.” In an attempt to explain the presence of these oddballs, many new theories are being suggested. While most still start with a disk of material orbiting a forming star, many suggest ways in which solar systems much different than our own might result. Why? Because what we’re learning is that the universe is a much stranger and more varied place than we imagined.
While science fiction has long posited the existence of other planets, up until recently, we could only guess whether there might be planets orbiting other stars in the universe. False reports of the discovery of planets outside our solar system, called extra-solar planets, have arisen since the 1940s, but only recently have we obtained convincing evidence that such planets do indeed exist.
Planets are very difficult to detect because they’re much smaller than stars and they shine only by catching and reflecting a small portion of their star’s light. Our sun, for example, is one billion times brighter than the planets that orbit it. If we look at a star through a telescope, the light from the star completely overwhelms that from any planets. As an example of how hard it is to find planets, consider that it too

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