"Benford-TheFarFuture" - читать интересную книгу автора (Benford Gregory)

ours, there could even be explosions (supernovas) if its mass is great enough.)

To stave off this fate, a cosmic engineer need only note that at least ninety
percent of the hydrogen in the star is still unburned, when the cycle turns in
desperation to fusing helium. The star's oven lies at the core, and hydrogen is
too light to sink down into it.

Envision a great spoon which can stir the elements in a star, mixing hydrogen
into the nuclear ash at the core. The star could then return to its calmer,
hydrogen-fusing reaction.

No spoon of matter could possibly survive the immense temperatures there, of
course. But magnetic fields can move mass through their rubbery pressures. The
sun's surface displays this, with its magnetic arches and loops which stretch
for thousands of kilometers, tightly clasping hot plasma into tubes and strands.

If a huge magnetic paddle could reach down into the sun's core and stir it, the
solar life span could extend to perhaps a hundred billion years. To do this
requires immense currents, circulating over coils larger than the sun itself.

What "wires" could support such currents, and what battery would drive them?
Such cosmic engineering is beyond our practical comprehension, but it violates
no physical laws. Perhaps, with five billion years to plan, we can figure a way
to do it. In return, we would extend the lifetime of our planet tenfold.

To fully use this extended stellar lifetime, we would need strategies for
capturing more sunlight than a planet can. Freeman Dyson envisioned breaking up
worlds into small asteroids, each orbiting its star in a shell of many billions
of small worldlets. These could in principle capture nearly all the sunlight. We
could conceivably do this to the Earth, then the rest of the planets.

Of course, the environmental impact report for such engineering would be rather
hefty. This raises the entire problem of what happens to the Earth while all
these stellar agonies go on. Even if we insure a mild, sunny climate, there are
long term troubles with our atmosphere.

Current thinking holds that the big long term problem we face is loss of carbon
dioxide from our air. This gas, the food of the plants, gets locked up in rocks.
Photosynthetic organisms down at the very base of the food chain extract carbon
from air, cutting the life chain.

We might fix this by bioengineering organisms that return carbon dioxide. Then
we would need to worry about the slow brightening of our sun, which would make
our surface temperature about 80 degrees Centigrade in 1.5 billion years.
Compensating for this by increasing our cloud cover, say, would work for a
while. A cooling cloud blanket will work for a while. Still, we continually lose
hydrogen to space, evaporated away at the top of the atmosphere. Putting water
clouds up to block the sunlight means that they, too, will get boiled away. Even
with such measures, liquid water on Earth would evaporate in about 2.5 billion
years from now. Without oceans, volcanoes would be the major source for new