50th Anniversary of the Starfish Prime Nuclear Weapon Test Today 190
The Bad Astronomer writes "50 years ago today, the U.S. detonated a nuclear weapon 240 miles above the Pacific Ocean. Called Starfish Prime, it was supposed to help U.S. scientists and the military understand how the Soviets might try to stop incoming nuclear missiles. What it actually did was blow out hundreds of streetlights in Hawaii 900 miles away, damage a half dozen satellites, and create artificial aurorae and intense radiation zones above the Earth. It taught the world what an electromagnetic pulse (EMP) was, and what the effects might be from a powerful solar flare, a nearby supernova, or a gamma-ray burst."
Someone's got a case of the "s'posed tas" (Score:5, Interesting)
A somewhat similar idea (but not too similar) is the idea of X-ray pindown. To facilitate an attack, the aggressor would detonate a neutron bomb high over the target country, bathing it in x-rays so harsh that the target country's ICBM's would be damaged if they tried to launch in retaliation.
Another interesting aside (at least I think it is): the early anti-ballistic missile programs, Sentinel and Safeguard, were designed to destroy incoming nuclear warheads by... blowing them up with other nuclear warheads. This had the positive effect of taking out one or two incoming warheads, and the very negative effect of blinding the system's radar to any other incoming warheads.
Mind your emissions, gentlemen.
Re:and gave birth to... (Score:3, Interesting)
I'd like to see a science fiction story with a probe landing on Venus and finding evidence of a nuclear weapons accident destroying what used to be a planet covered by forests.
More likely to find highways choked with derelict SUVs
Re:Not really supernovae and gamma-ray bursts (Score:5, Interesting)
I guess, the nuclear test would have to be much much closer to register as one pixel vs. the sun, if you want to compare it vs. a type 1a supernova. Maybe 100m from the nuclear blast is about similar to type 1a supernova at 150,000,000,000m, or about where the sun is, and then *maybe* you may compare the two on the scale of one pixel (the nuke) vs. sun in terms of brightness over about 5 seconds.
A nuclear device can only come close to brightness comparison if you are looking at scales of microseconds or similar. And that comparison only works because of the limitations of speed of light!
To keep it in perspective, a supernova can blow away Earth's like planet atmospheres over a distance of *light years*. It can irradiate and destroy ozone layers at a distance of hundreds and hundreds of light years, and some at a few thousand light years.
Some cosmic BOOMs are so large, that they will glow more brightly than the rest of the visible universe combined. And the longer you look, the larger BOOMs are seen :)
http://www.telegraph.co.uk/science/space/7893771/Nasa-satellite-blinded-by-biggest-ever-star-explosion-seen-in-space.html [telegraph.co.uk]
Re:Are you ready for an EMP ?? (Score:5, Interesting)
While the effects you describe are definitely real and a huge issue, significant-footprint EMP really requires a thermonuclear device, not a "small" fission one.
For maximum EMP damage, 10,000 feet is far too low an altitude. You want a minimum of 50km altitude. So, to do a EMP, you must have orbital launch capability (i.e. Intermediate Range Ballistic Missile or better capability). Loading a nuke onboard a plane and detonating it at 40,000 feet won't work for producing an EMP of any effect.
Maximum area of the EMP is limited to "line of sight" to the detonation point. So, detonating higher in the atmosphere gives a larger potential EMP radius. However, the higher the altitude, the lower the total amount of radiated energy from the blast converted into EMP. This is primarily due to the atmosphere absorbing a significant amount of the energy before it reaches ground level. And, of course, EMP is not some binary works-or-not; it's a power level, and each device has a different level of interference that it can withstand before frying. So, you're faced with a tradeoff: the higher you detonate the warhead, the larger the potential area of the EMP, but the weaker the EMP is throughout the entire area.
Realistically speaking, warheads under 100kt don't produce usable EMP. At the minimum effective EMP altitude of about 30km, 100kt produces a useful EMP (one which will fry unshielded simple commercial electronics) directly underneath the weapon detonation, perhaps in a hectare or so. A 200kt weapon (the maximum effective yield of a non-boosted, pure fission weapon) could produce a EMP with maybe a few km or so radius.
Effective EMP areas require 300-400kt or more, which requires, at minimum, a boosted fission/fusion weapon, which is much more difficult to build than a pure fission weapon. With these, you might be able to get an EMP radius of 50-100km or so. To get the really big EMP, you need a thermonuclear weapon, ideally in the low MT range (2-5MT). These are the weapons that were used in the USA and USSR's Fractional Orbital Bombardment systems you read about in fiction books. They can produce the 1000km+ radius effects.
Given all the above, to do any real EMP, you need BOTH orbital launch capability, AND boosted fission nuclear weapon ability. At this point, a total of 6 countries (USA, Russia, UK, France, China, India) have this ability, with two possibly working on it (Pakistan, North Korea), and nobody else getting there anytime soon (even Israel is unlikely to have the requisite missile capability). In the big scheme of things, not something that we really have to worry about more than general nuclear weapon use, as EMP use is far beyond the capabilities of any non-state actor, and fairly obvious if any state-level attempt is being made to produce one.
-Erik
Re:Sounds like fun! (Score:5, Interesting)
Here's how crazy of an effect [wordpress.com] nuclear bombs have had on our atmosphere. Basically, artifacts from the latter half of the 20th century and much of the 21st century will not be able to be reliably carbon dated in the future. Even if you want to include a compensation factor, the concentrations for a given location at different times over the lifespan of an organism and the organism's uptake at different points in its life aren't readily quantified.