How you can save the world, or more precisely, what I can do to save the world, has driven me full time for the past 7 years. As a former astronaut, sometime scientist, and dogged good public policy pusher, I’ve focused my efforts on preventing the largest natural hazard that we know of: asteroid impacts with Earth. One wiped out the dinosaurs (the polar bears of cosmic extinction) and may well, if we cannot ultimately get our act together, wipe us out one day.
The fascinating thing about asteroid impacts, the largest of natural hazards (albeit a cosmic one), is that we can actually prevent them. With current space technology we can slightly modify the solar system to help insure the survival of life on the planet. We can subtly modify the orbit of a threatening asteroid and thereby prevent it, and ultimately its millions of companions, from ever destroying life on Earth again. Will we? Or will we not? Are we? Or are we not still dinosaurs? Interestingly, technology and cost are not the issue. The answer will lie in whether or not we value ourselves as a species over ourselves as a collection of nations.
Rusty, you probably have the most insight into that question. Do you believe that there
By Coconutfarmer at 10:59 AM ON 08/25/08
Rusty, you probably have the most insight into that question. Do you believe that there would potentially be an unwillingness in the global community to try to prevent an asteroid impact? Do you feel that one country's short sightedness may actually cause it to believe it could gain a strategic political advantage over another by allowing an asteroid to impact a nation far removed from its own?
I believe that each person is an individual, often focused on their own individual pursuits, and more often than not, at the cost of ignoring the needs of others. Yet through it all, one trait I have always found in people is their ability to put their aside own interests and come together when they are threatened by something that will hurt our society. I like to believe we would do this whether it was our community, our country, or our planet. After all, we are part of a global society now and what harms one, affects all.
By Rusty at 3:01 PM ON 08/25/08
Coconut..
The hope is your faith expressed in your second paragraph.
The challenge is that in NEO deflection (NEO = asteroid, but more general) is not a simple matter of "disappearing" the asteriod. For each potential NEO impact there is a line which crosses the planet and extends both in front and behind the planet. Think of this line as the locus of points formed by the NEO's position at its time of impact were it to arrive anywhere between very early, and very late for the Earth impact. A very early arrival on the part of the NEO and it arrives at the "intersection" before the Earth arrives, thereby it passes in front of the Earth. A late arrival time means that it passes behind the Earth. An on-time arrival (or near on time) and it hits somewhere on the Earth's surface... along the line.
A deflection is the process of slightly increasing or decreasing the NEO's velocity (a decade or so prior to impact) such that it arrives either too early or too late and the Earth is not in the intersection. BUT... if it was going to hit in the "middle" of the line across the Earth the deflection *process* essentially drags that impact point off the Earth along the line... until it will pass safely ahead of or behind the planet.
However there are countries, people... and politicians along that line who were not initially at risk. The impact point has to be dragged either toward the "leading edge" of the Earth or the trailing edge. Which way? The issue is clearly that something might happen to interrupt the deflection process thereby now causing the NEO to impact in a different place along the line. So those nations along the line toward the leading edge of the planet say, "drag it off the trailing edge", and visa versa for the folks toward the trailing edge.
NEO deflection = risk shifting in the process of risk elimination. Nations and peoples not initially at risk will need to accept a temporary increase in risk in order to drop the risk to zero for everyone. This will not be an easy political decision and without agreement it will be very difficult for any space faring nation (or consortium) to execute such an operation due to the liability involved in a potential failure.
This is one of many such international legal and political challenges. In the abstract we love to see ourselves as part of the human community... but we tend to act as nations with strong self-interest. For political leaders to agree to risk their population, however temporarily and however slightly, for the benefit of all will not be easy.
By louisofearth at 9:37 PM ON 08/25/08
Defending Earth by Orbiting Earth-Safe Nuclear Devices
High Earth orbit is the best place to put a system of missiles carrying atomic explosives for destroying or deflecting incoming Asteroids or Comets. Ideally, two groups of these devices would be in both equatorial and polar orbits. From these two orbits, they can be launched in nearly any direction in less than 48 hours. To launch a response from the Earth’s surface it would take weeks or months.
Current designs for Atomic Weapons require the use of chemical explosives to initiate and enclose the preliminary chain reaction. Instead of explosives, the design for Earth defending atomic explosives would use the speed differential between an incoming Asteroid or Comet and the device. The device would use the impact energy to assemble and detonate the device. The device’s relatively fragile construction and lack of explosives would not permit it to enter the Earth’s atmosphere and impact at a high enough velocity to function effectively.
There are currently international treaties that wisely bar the orbiting of atomic weapons. Negotiations can be begun that would permit the orbiting of these Earth-Safe nuclear devices. Before launch, they would be inspected to verify that they are incapable of being used against the Earth as either an air-blast or a ground impact device. In a paper that may be given, (if the abstract is accepted, and I can afford to go), at the LEAG-ICEUM-SRR meeting in Cape Canaveral, Florida Oct 28-31 2008 , I propose, and give an example of an atomic explosive that is physically incapable of attacking targets on the Earth’s surface.
By Coconutfarmer at 9:10 AM ON 08/27/08
Rusty, Thanks for the explanation, it helps put things into perspective. It also seems to demonstrate that the likelihood of such an occurrence is at this point in our universe's history seems to be very low... That being said it's obviously still a possibility and one with tragic reprecutions, even more so as human communities grow larger and more closely together. Is this plan, outlined in LouisofEarth's comment feasible? It was my understanding that it is questionable if a nuclear impact would be strong enough to affect the trajectory of an asteroid unless it was an incredible distance away from the planet... So much so that it would either be very hard to detect or at least of questionable threat.
LouisofEarth, I think the treaties are necessary because the threat of an asteroid strike are low but the temptation for an irresponsible government to use these weapons to threaten a human population is very high. I almost think I'd take my chance on the asteroid strike before I'd put my faith in our leaders to do the right thing.
By louisofearth at 7:04 AM ON 08/28/08
It appears that Mr. Schweickart has fallen down a rabbit hole in New Mexico http://www.sandia.gov/NNSA/ASC/ . My name is pronounced “Louie”.
By Coconutfarmer at 9:59 AM ON 08/28/08
Yes, I think this site is really just a trial extension or pet project for someone at Sci-Fi... It has potential but does very little to encourage on-going discussion of the issues it blogs about.
I guess that part is up to us.
The project you're working on sounds quite interesting, from what I can fully comprehend, but I'm curious, and I pass no judgments here, is the placement of nuclear weapons in space solely for the protection of Earth from extra-terrestrial threats? Can the technology be modified to threaten a human population? Not that I think that this would come from US or even Russia (though the latter has demonstrated a somewhat reckless and heavy-handed use of force) but as other, potentially more aggressive, countries develop space programs can we guarantee that this technology could not start a new Cold War?
Also maybe you could answer the question I asked of Mr. Schweickart. Can a nuclear strike successfully and feasibly change the trajectory of an asteroid if it is close enough to Earth to be detectable as a possible threat?
By louisofearth at 11:11 PM ON 08/28/08
This design is a radical departure from what I know of weapons design. Modification is never impossible but it would be a very poor return over simply building a weapon from scratch. The element of surprise is also removed since nothing could move to or from high Earth orbit without being seen.
The primary use for this system would be for threats with very short lead times. An example would be a 300-meter object that is moving at 12km per second and is detected when it is only 3 days from Earth. Impact will be off the west coast of the United States.
One or more of these nuclear devices in high Earth orbit will fire its solid rocket motors to put it on an intercept course. Solid rocket motors should be used since they have low maintenance requirements. An Earth defending system might be in orbit for decades before they are used.
Only rudimentary analysis of the object is possible. Unless the object is a very strong solid, it will be broken up into smaller fragments by the impact and detonation. One or more of the fragments will probably exceed 30 meters. Fragments this size and larger are capable of a Tunguska or a Canyon Diablo event. An ocean impact by fragments of this size should produce only smaller regional tsunamis rather than the ocean spanning one produced by the complete object.
A very rough guess is that greater than 90% of the objects energy will miss Earth or be dissipated in the upper atmosphere. If more than one device is used, the following ones could standoff and see if they can shatter any large surviving bodies.
It isn’t a happy ending though, casualties could exceed tens of thousands. Property losses would be staggering. Debris from the initial space detonation will probably obliterate our satellites and space infrastructure. Yet it could have been far worse.
More resources should be used to detect the threats earlier. A simple and reliable means must be found for not just deflecting the object but for fundamentally changing its orbit. Only an orbital change will remove it as a threat in the future.
By louisofearth at 11:52 AM ON 08/31/08
My Bad.
The Canyon Diablo (Barringer) Crater would require a nickel-iron meteor of 50 meters not 30 meters in diameter. At a minimum, a Tunguska Event would need a 100 meter diameter stony or carbonaceous meteor.
What the asteroid is made of matters a great deal. A 300-meter diameter ball of ice moving at 12000 meters per second equals approximately 4.8 megatons or 370 Hiroshima size bombs. A 300-meter diameter ball of nickel-iron moving at 12000 meters per second equals approximately 37 megatons or 2800 Hiroshima size bombs.
The surface rupture energy that produced the 2004 Indian Ocean tsunami was estimated at 26.3 megatons.
I also forgot the EMP Pulse, which would overload the power grid if it were not shut down before impact. Thanks to maximizing shareholder return, America now has the least amount of spare capacity and spare parts of any industrial nation on the planet! Maybe Martha Stewart could figure out how to make candles out of automobile tires. You also might want to put a few extra pounds on rover, just in case.
By louisofearth at 4:43 PM ON 09/01/08
My (not showing my work, revenge of my few math teachers) Bad. (1/2*MV2) Not Just Mass X Velocity Squared
The Canyon Diablo (Barringer) Crater would require a nickel-iron meteor of 50 meters not 30 meters in diameter. At a minimum, a Tunguska Event would need a 150 meter diameter stony or carbonaceous meteor moving at 20,000 meters per second
What the asteroid is made of matters a great deal. A 300-meter diameter ball of ice moving at 12000 meters per second equals approximately 2.43 megatons or 187 Hiroshima size bombs. A 300-meter diameter ball of nickel-iron moving at 12000 meters per second equals approximately 18.5 megatons or 1422 Hiroshima size bombs.
Even divided in half this amount of force (kinetic energy) would still leave a mark.
By Lucinda at 10:02 AM ON 05/06/09
I just want to say, I love the grphics on the picture. I was only browsing 'sustainable development' for my assignment in 'Animal care' and then a picture of the earth came up, so I desided to google 'earth' and this awesome picture appeared. I will be sure to visit this site again to collect more information as I am studying A LEVEL Geography in september 2009.
thank you for the insparation.
Lucinda
By Cindy at 12:42 AM ON 06/04/09
My little sister isn't ready to die on the 2012 because want see my high school program and she doesn't want to miss it and she said that she loves me and always pray to god and ask god to keep the asteroid away and she's only 11 years old and I LOVE MY LITTLE SISTER and the same thing as me, I'm not ready to die either and i care about my whole family and friend and i pray with my little sister every night and day. PLEASE SAVE OUR WORLD, and i want to see my little sister to be a big girl just like me as her big sister. PLEASE SAVE OUR WORLD!!!!!!!!!!!!!!!!!!!!!!!!
By GarykPatton at 9:35 PM ON 06/15/09
I have been looking looking around for this kind of information. Will you post some more in future? I'll be grateful if you will.