|
Rigid sphere?
There has been a great deal of informal
discussion
about the engineering of Dyson Spheres [see
Robert Bradbury's site] [link is
currently broken] as well as Dyson Sphere generalizations
sometimes called
Astroengineering
Constructions or AC. A putative shell formed from Earth at Earth’s
distance
from the Sun would be 4 mm thick, while a shell formed from
Jupiter would
be 5 m thick at Earth’s radius and 0.2 m thick at Jupiter’s distance
from the
Sun.
In the correspondence in Science Magazine following
Dyson’s article
several writers drew attention to problems associated with constructing
a
sphere, in particular a rigid sphere. Dyson responded that a rigid
sphere was
impossible and that what he had in mind was a swarm of objects. For
this
article the word “sphere” is used to designate any assembly including
rings.
|
Energy to assemble
Another objectionto the Dyson
Sphere concept is the large energy required to assemble a sphere.
Dyson
states that his model case would require the output of the Sun for 800
years. Note
that a ring (often called a “Ringworld” from the science fiction novels
of L.
Niven) would require less energy to assemble but would also not be as
effective
at collecting stellar energy. Seen through the ring a ringworld could
shield
the host star like a Dyson sphere. Viewed perpendicular to the ring
plane it
would not have a strong signature.
Nature of a Dyson Swarm
Finally, a non-anthropocentric
view
is
helpful in considering the possible nature of Dyson’s swarm. It might
well
consist of something like a flock of constantly-renewing 100 micron
thick
photocells powering computer chips! |