Transcript eeyore.astro.illinois.edu

Terraforming
John Tobin
Overview
What is terraforming?
-- planetary engineering to make a world more earthlike
Why study terraforming?
-- learn more about our own planet
-- perhaps essential to our civilization's survival
-- possibly recognize extraterrestrial terraforming
opterations
Crazy Ideas?
Terraforming isn't such a crazy idea when compared to our
level of technology and the level of technology when other
gradiose ideas have been formed.
Crazy Ideas that are reality:
--Flight (DaVinci late 1400s)
--Breaking the sound barrier
--Spaceflight (Jules Verne 1870 – From the Earth to the Moon)
--Atomic Energy (Jules Verne 1864 – 20,000 Leagues...)
--Computers, personal computers too (Babbage 1800s)
Crazy Ideas?
Private Spaceflight 2004 Burt Rutan/Mike Melvill
Finally:
Warp Drive Zephram Cochrane 2061
How to Terraform?
Canidate Worlds
Mars
Pros
--already has a thin atmosphere
--potentially has large amounts of
water and CO frozen
Cons
--need to import large amounts of volitiles
--farther from the sun
Venus
Pros
--thick atmosphere already
--no shortage of solar heat
Cons
--slow rotation period, needs to be spun up
--must remove large amounts of gas
2
How to Terraform?
Canidate Worlds cont...
Moon
Pros
--nearby
Cons
--low gravity, atmosphere will escape over
thousands of years
--large amounts of volitiles need to be imported
from asteroid belt or outer solar system
How to Terraform?
Resources
Asteroids
--Many are rich in water, nitrogen, and carbon, Type: C
--Most Type C located in main belt, estimated 75% of all
asteroids are Type C
Moons
--moons of Saturn specifically, many are thought to
be rich in ice and other volitile compounds
--also, for use as a stabilizing force on the planet to limit
precession of the rotational axis
Planetary crusts
--Mars is thought to be rich in compounds that are
locked away in the regolith
How to Terraform?
Mathilde – NEAR Flyby on 27 July 1997
Type C Asteroid
61 km diameter
How to Terraform?
Resources cont...
Man-made
--machines to break down compounds in planetary crust
--genetically engineered cyanobacteria (blue-green algae)
--super greenhouse gases, CFCs, to induce warming and
allow a planet (Mars) to thaw
--gases possibly locked in permafrost
--mirrors to induce melting of ice caps on Mars
--spread dust on icecaps to reduce absorbtion
--mirrors or dust put in orbit of inner planets to reduce
solar flux
Rockets
--nuclear, fission or fusion rockets could help solve some
problems, it has been proposed that volitiles from
asteroids or moons would be used as fuel
Nuclear Rockets
--NERVA Engine, designed and
built during the 1960s
--Fission reactor, hydrogen for
fuel
--250,000 lbs thrust
--barely scratches surface of
potential
Problems of Terraforming
Lack of knowledge
--Earth's biosphere is still not fully understood
--numerous feedback mechanisms are present that are
not comprehended or accounted for
Technical problems
--no proven methods for moving large objects, asteroids
and moons
--mass-drivers are possible solutions
--gravity assists from outer planets
--spacecraft are still terribly slow
--ideally would want to accelerate at 1G for entire trip
--nuclear is a “bad-word” in our society, many political
roadblocks to starting nuclear rocket development back
up
Mass Driver
--E-mag fields accel.
masses to high speeds
--Newton's third law
requires that the source
mass will feel the reaction
force
--reaction force = ∆v
--good for moving asteroids
Mass driver on the moon, used to “throw rocks”
back to Earth.
TANSTAFL!
Problems of Terraforming
Time
--Terraforming cannot be achieved within a lifetime
--process of thousands or even millions of years
--will need constant funding, maintenance
and stable government
Ethics
--Don't fully understand our own planet and are
potentially doing irreparable damage to it.
--Should other planets such as Mars be allowed to
potentially evolve on their own?
--Gaia hypothesis?
--Does primitive life deserve to thrive on it's own without
our changing of the climate to one that would probably
be poisonous?
--Would we recognize life that is unlike our form of life?
Reverse Jupiter Swing-by
--objects in the outer solar system require less ∆v to change
orbit to a more elliptical one, outer solar system objects
would be much easier to move than a main belt asteroid
Possible Benefits
--We will essentially become near omniscient in the
workings of the Earth if we are going to try to replicate it.
--We'd learn how to repair damage to our planet or change
the climate if runaway greenhouse or deep-freeze likely
to occur
--We would probably learn how to deflect asteriods that are
on a collision course. (e.g. Mass drivers)
Extraterrestrials?
--If we become skilled terraformers, we will know the signs
of terraforming and possibly detect it
Dyson Motor
--conceptual device to spin
up a planet such as Venus
or Mercury that is tidally
locked
--uses HUGE magnetic field
to spin up planet, possibly
detectable
Extraterrestrials?
Array of space based mirrors for warming portions of
planets. Perhaps the TPI could detect these, even larger
mirrors than these are envisioned.
Dyson Sphere
--gravitational
signature, but
no light from
star escapes
--mass if titanium:
V * rho
8.48x10^23 * 4510=
3.82x10^27 kg
--carbon:
2.98x10^27 kg
--1.5 to 2 Jupiters
Ring World
--Large ring structure constructed around a star at
approximately 1 AU
--using Dyson sphere thickness of 3m and a height of
1,600,000 km with 1600km 1m thick walls
--mass of Carbon ring: 1.59x10^22 kg
Titanium ring: 2.04x10^22 kg
Earth mass: 6.0x10^24 kg
-still grandiose but much more realistic than Dyson sphere
More Extraterrestrials?
--Terraforming untimately deals with the lifetime of a
technological civilization
--If they destroy their home planet's environment, they need
someplace to go
--Learn to better control climate of home planet to prevent
ecological disasters, runaway greenhouse or perpetual
ice age (Earth is on a precipice between the two)
--Colonize the galaxy with the means of travel
Why Terraform?
--Everest syndrome
--Botany Bay syndrome
--Mayflower syndrome
--Unemployed soldier syndrom
--Wild West Syndrome
“A map of the world that doesn not include Utopia is not even worth
glancing at, for it leaves out the one country at which Humanity is
always landing. And when Humanity lands there, it looks out, and
seeing a better country, sets sail. Progress is the realization of Utopias.”
-Oscar Wilde
Bottom Line
We'll never know what we're
really capable of if we don't try!