overshadow in both tempo and magnitude the triggering events—con-
sequences such as an explosive deterioration in the quality of life for
Finally, "to fuse" means to combine, unite, join. The oneness or
unity of nature has been a theme of poets and philosophers for millen-
nia. The unity of the laws of nature has been a theme of science since
Galileo. Physicists have demonstrated that the laws of motion hold
true on spaceships and distant stars as well as in earth's laboratories.
Biologists have taught us that the same DNA
the trip as measured by
ground clocks approaches L/c, but the proper time approaches zero! If a
spaceship travels to a distant star, the time of the trip as measured by
clocks on the spaceship goes to zero as the ship's speed approaches e. This
consequence of relativity forms the basis for much fanciful speculation
about space travel. In principle, there is no limit to the distance one could
travel in one's own lifetime.
EXAMPLE. A spaceship travels from earth to Alpha Centauri at speed
0.8e. The distance between earth and Alpha Centauri is 4 light-years, mea-
the speed (relative
to 5) of a frame in which E occurs at the same place as Eo. If E is in the elsewhere
of Eo, find the speed of a frame in which it is simultaneous with Eo.
5.2. Refer to the three events E1 , E2 , and E3 of problem 5.1. For each pair of
events, (1,2), (2,3), and (1,3), find the value of (~S)2 and characterize the interval
between the events as spacelike, timelike, or lightlike. Which pairs of events could
be causally related?
5.3. Consider problem 3.8, in which a light pulse catches up to a spaceship.
(a) Construct the space-time diagram for the
Of course, contemporary shopping malls are far from the modest strip
malls of my youth. “It’s like a giant spaceship,” is the way Oscar, the store
P R E F A C E A N D A C K N O W L E D G M E N T S
viii • P R E F A C E A N D A C K N O W L E D G M E N T S
clerk who gave me a tour of Titan Shopping Mall in Bogotá, Colombia,
explained it. He was referring to the enclosed, curvilinear architecture
and futuristic feel of the mall, which gave the impression that a massive
spaceship had landed from nowhere, an alien structure with little relation-
ship to the
, Ecologo certified, and manufac-
tured by BioGas energy.
Hernandez, Migra! 1/11/10 1:12 PM Page iv
For my mother
because you taught me to write
For my father
because you inspire me to take on the world
For my brother
because you teach me that change is possible
For my husband
because you are beautiful
For my children
because I love you
Hernandez, Migra! 1/11/10 1:12 PM Page v
Hernandez, Migra! 1/11/10 1:12 PM Page vi
[Spoken] It’s a bird!
It’s a plane!
No man, it’s a wetback.
[Sung] He came from the sky, but he is not a plane.
He came in his spaceship from Krypton,
(c) What is the spatial distance between the points at which the pulses were
(d) How much time elapsed between the emission of the first pulse and the
meeting of the two pulses?
(e) Did the pulses meet at the midpoint of the car? How could this answer
have been predicted?
4.5. Spaceship A passes earth at earth time t = 0 at speed O.Be in the direction of
the star Xerxes. At the same time (according to earth frame clocks) spaceship B
passes Xerxes at speed 0.625e in the direction of earth. Assume that earth and
Xerxes are at rest relative to one another and
When I was growing up, my parents often accused me of living more in
my imagination than in the real world. And I’m not sure they were
wrong. My nose always stuck in a book, my head in the clouds, as it
were, I fought monsters, cast magic spells, flew spaceships, and saved
the day in every story. Well, almost every story. Take, for example, my
first attempt at being a superhero. It was—as it was, I imagine, for many
others—short-lived. I was about five years old, and my growing comic
book collection had convinced me that I understood exactly how Super
windup Popeyes and
racist “Alabama Coon Jiggers,” outsourced production to Japan. After World
War II, Japan became an exporter of robots and space toys made of tin cans
to an American market eager for science-fiction and space themes: Japanese
spaceships looked like hastily recycled tanks and other war toys, and the toy
figures looked alien to Westerners because Japanese toy makers could not
afford to license images of movie and TV icons like Flash Gordon and Space
By the late 1960s, however, Japan was producing quality Datsuns and
other cars for export, and it