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Jim:
See: http://neo.jpl.nasa.gov/ A sub part of this site was mentioned in the article that you posted Friday, but I’d recommend posting this main page of the site.

Let’s look at two more things. 1.) NASA just recently proved they can hit an asteroid with a satellite. Doesn’t that strike you as at least a little odd they would spend the money to do that just for researching the impact? 2.) Now, did you also notice that the military is working on a new type of “bunker busting” nuclear penetration bomb that survives for 100 milliseconds, burrowing into the ground through concrete and steel, and then goes off? Put the two together and you have a far more realistic approach to busting an approaching asteroid than was portrayed in the movies Deep Impact or Armageddon. – Rourke

Mr. Rawles,
I have been enjoying reading your excellent blog. Some thoughts for you on the post from Rourke and the troubles presented by EMP.

Let’s say I build a Faraday cage in my basement, and drive a ground rod just for it. Now let’s say that my home is grounded–most are. If the physical arrangement of my cage is such that I can touch the cage and something else metallic in my basement, such as a washer, dryer, freezer or some such because there are now two separate ground pathways there can be a voltage difference between the two and since I’m touching both I become the conductor for any voltage differences. Does that make sense?

Grounding systems for some large installations can be huge and very complex, but they are all, electrically one system so no voltage differences can exist.
Hope this helps. – Catshooter

Electromagnetic pulse (EMP), is now a commonly know effect thanks to movies showcasing the nuclear version such as Goldeneye (James Bond) and the remake of Ocean’s 11 which shows a non-nuclear version. The real question for survivalists is: what is EMP actually going to do to my valued equipment and what can I realistically do about it? Let’s start with lightening since it is very well understood. We know that lightening will tend to seek out the highest conductive point that is grounded and then seek to flow through a conductor, often back and forth a few times, until the electrical charge imbalance between the cloud and ground is neutralized. To protect buildings, lighting rods have been erected on them historically to channel the electrical current around the building and into the ground.
With EMP the concept of channeling the energy away from what we wish to protect is somewhat similar. EMP is a pulse of energy, and travels through everything. The idea is to shield something from it my placing it in (surrounding it with) a conductive (metal) box that is then grounded (preferably into the earth). The conductive box thus channels a large amount of the electrical energy passing into it down the ground, sparing what is inside of it from the full force of the electro magnetic pulse.
The good news is such a Faraday Cage or Faraday Shielding need not be expensive. A metal file cabinet or inexpensive light weight gun safe will work. I bought a used heavy metal box that I think was originally used to keep coal or sand in. What you want is a complete and connected conductive metal (steel) exterior surface, not a grid or cage with gaps (this is why the term Faraday Cage is actually not a good term since with a cage people think of bars). [JWR Clarifies:  Actually, a cage-like structure would work, but the largest gap in the mesh would have to be less than 1/4 of the wavelength of the expected pulse. Hence, 1/2″ wire mesh should be sufficient.]  Ideally you should connect a very heavy gage electrical wire (monster cable or 220 volt heavy electric wire) to a stand-alone dedicated ground (usually a copper rod drilled in below your basement floor). Some people say connect it to your copper plumbing or steel pipes. The problem with this is that the pipes could act as an antenna and actually channel energy to the Faraday shield. Just talk to an electrician about putting in a ground.
Although the Faraday principal says the electrical items are safe inside as long as they are not connected or touching the exterior shield, I think you still have to worry about the spark gap. Thus my advice is to put your expensive electronic stuff (computer, laptop, night vision, digital camera, radio equipment, etc.) into plastic tubs with plastic lids, and that then into the Faraday Cage. Plastic of course was developed as an insulator for radar in WWII, which due to it’s high voltage had to have an insulator between metal parts so the electricity didn’t just spark through the air (spark gap). Mineral oil has also been used as an insulator in high voltage equipment.
Remember, having anything plugged in, or hooked to an antenna defeats the purpose of shielding around it as you have provided an electrical highway [an unintentional antenna] right in. The use of a [lightning protection fast] fuse on such necessary plugged in equipment is probably your best bet as I fear a circuit breaker is not going to react quickly enough to save delicate equipment. However, I am not an electrical engineer nor am I claiming to be an EMP expert here. I am just trying to apply practical solutions to the problem and welcome the constructive criticism or correct by others who are more knowledgeable and can offer better solutions to the problem. – Rourke   http://groups.yahoo.com/group/survivalretreat

More on the subject:
Understanding EMP: http://www.geocities.com/CapeCanaveral/5971/emp.html  
EMP Bomb: http://www.abovetopsecret.com/pages/ebomb.html 
Faraday Cages: http://www.unitedstatesaction.com/emp_and_faraday_cages.htm#qst 
Duncan Long on EMP: http://standeyo.com/News_Files/NBC/EMP.protection.html

The statistical chance of a large asteroid striking the Earth in any given year is very small–in fact almost statistically insignificant–since such events occur on average only once in more than 10,000 years. However, the consequences if such an event were to occur would be tremendous–perhaps even an “extinction level event.”  Recent advances in astronomy have led to the realization that a large number of Near-Earth Objects (NEOs) that have true “Earth-crossing” orbits was far greater than was originally estimated.  See: http://cfa-www.harvard.edu/cfa/ps/mpc.html

The Tunguska, Siberia event in 1908 and the Curucá incident in Brazil in 1930 (in both of which it is suspected that a small asteroid vaporized before striking the Earth) are indicative that he asteroid threat is real. The1997 asteroid XF11’s near miss (see: http://ssd.jpl.nasa.gov/ca_97xf11.html) should have served as a wake-up call, but politicians tend to be complacent about subtle threats unless they suddenly become non-subtle and a goodly number of registered voters get obliterated. 

Here is another interesting site to peruse: http://www.pibburns.com/catastro/impacts.htm

It is not reassuring to read that a number of  asteroid “near misses” (in terms of astronomical units)  were detected only after the asteroid had passed.

A recent article in England’s Guardian newspaper outlined the threat posed by the 390 meter wide Apophis asteroid, which could strike the Earth in 31 years. An asteroid that large could represent the risk of major climate change but not quite an extinction level event. (That would probably take an asteroid more than a kilometer in diameter.) In part, the article stated:  “NASA has estimated that an impact from Apophis, which has an outside chance of hitting the Earth in 2036, would release more than 100,000 times the energy released in the nuclear blast over Hiroshima. Thousands of square kilometers would be directly affected by the blast but the whole of the Earth would see the effects of the dust released into the atmosphere.” To read the entire article, see: http://www.guardian.co.uk/space/article/0%2C14493%2C1660485%2C00.html

The World Tribune recently published some interesting excerpts from the new book, “War Footing: 10 Steps America Must Take to Prevail in the War for the Free World“, by Frank J. Gaffney and Colleagues, reprinted with permission from the publisher, Naval Institute Press, Annapolis, Maryland. OBTW, I had the privilege of meeting Frank Gaffney, back when I was on the editorial staff of Defense Electronics magazine. I was favorably impressed with both his acumen and his common sense. For the full text of the review, see:  http://www.worldtribune.com/worldtribune/05/front2453711.9284722223.html