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PHYSICS OF THE IMPOSSIBLE
tial impact took place 65 million years ago, when an object about 6
miles across slammed into the Yucatan Peninsula of Mexico, creating
a crater about 180 miles in diameter, wiping out the dinosaurs that
up until then were the dominant life-form on Earth. Another cosmic
collision is likely on that time scale.
Billions of years from now the sun will gradually expand and consume the Earth. In fact, we estimate that the sun will heat up by approximately 10 percent over the next billion years, scorching the Earth.
It will completely consume the Earth in 5 billion years, when our sun
mutates into a gigantic red star. The Earth will actually be inside the
atmosphere of the sun.
Tens of billions of years from now both the sun and the Milky Way
galaxy will die. As our sun eventually exhausts its hydrogen/helium
fuel, it will shrink into a tiny white dwarf star and gradually cool off
until it becomes a hulk of black nuclear waste drifting in the vacuum
of space. The Milky Way galaxy will eventually collide with the neighboring Andromeda galaxy, which is much larger than our galaxy. The
Milky Way's spiral arms will be torn apart, and our sun could well be
flung into deep space. The black holes at the center of the two galaxies
will perform a death dance before ultimately colliding and merging.
Given that humanity must one day flee the solar system to the
nearby stars to survive, or perish, the question is: how will we get
there? The nearest star system, Alpha Centauri, is over 4 light-years
away. Conventional chemical propulsion rockets, the workhorses of
the current space program, barely reach 40,000 miles per hour. At that
speed it would take 70,000 years just to visit the nearest star.
Analyzing the space program today, there is an enormous gap between our pitiful present-day capabilities and the requirements for a
true starship that could enable us to begin to explore the universe.
Since exploring the moon in the early 1970s, our manned space program has sent astronauts into orbit only about 500 miles above the
Earth in the Space Shuttle and International Space Station. By 2010,
however, NASA plans to phase out the Space Shuttle to make way for
the Orion spacecraft, which will eventually take astronauts back to
the moon by the year 2020, after a fifty-year hiatus. The plan is to es-
PHYSICS OF THE IMPOSSIBLE
tial impact took place 65 million years ago, when an object about 6
miles across slammed into the Yucatan Peninsula of Mexico, creating
a crater about 180 miles in diameter, wiping out the dinosaurs that
up until then were the dominant life-form on Earth. Another cosmic
collision is likely on that time scale.
Billions of years from now the sun will gradually expand and consume the Earth. In fact, we estimate that the sun will heat up by approximately 10 percent over the next billion years, scorching the Earth.
It will completely consume the Earth in 5 billion years, when our sun
mutates into a gigantic red star. The Earth will actually be inside the
atmosphere of the sun.
Tens of billions of years from now both the sun and the Milky Way
galaxy will die. As our sun eventually exhausts its hydrogen/helium
fuel, it will shrink into a tiny white dwarf star and gradually cool off
until it becomes a hulk of black nuclear waste drifting in the vacuum
of space. The Milky Way galaxy will eventually collide with the neighboring Andromeda galaxy, which is much larger than our galaxy. The
Milky Way's spiral arms will be torn apart, and our sun could well be
flung into deep space. The black holes at the center of the two galaxies
will perform a death dance before ultimately colliding and merging.
Given that humanity must one day flee the solar system to the
nearby stars to survive, or perish, the question is: how will we get
there? The nearest star system, Alpha Centauri, is over 4 light-years
away. Conventional chemical propulsion rockets, the workhorses of
the current space program, barely reach 40,000 miles per hour. At that
speed it would take 70,000 years just to visit the nearest star.
Analyzing the space program today, there is an enormous gap between our pitiful present-day capabilities and the requirements for a
true starship that could enable us to begin to explore the universe.
Since exploring the moon in the early 1970s, our manned space program has sent astronauts into orbit only about 500 miles above the
Earth in the Space Shuttle and International Space Station. By 2010,
however, NASA plans to phase out the Space Shuttle to make way for
the Orion spacecraft, which will eventually take astronauts back to
the moon by the year 2020, after a fifty-year hiatus. The plan is to es-