A neutron bomb or officially known as one type of Enhanced Radiation Weapon is a low yield fission-fusion thermonuclear weapon (hydrogen bomb) in which the burst of neutrons generated by a fusion reaction is intentionally allowed to escape the weapon, rather than being absorbed by its other components.

Compared to a pure fission bomb ... a neutron bomb would emit about 10x the amount of neutron radiation. In a fission bomb ... gamma rays and neutrons is approximately 5% of the entire energy released; in the neutron bomb it would be closer to 40%.

The US, USSR, France and China (and possibly Israel) have all developed them, and/or implemented them.

The lethal dose (LD50) of 600 Rads would extend to about 1350–1400 meters

But they also have substantial blast effects (so you don't get to keep the buildings, etc).

And, the neutrons get absorbed by the atmosphere (perhaps dictated by humidity).

But the basic function I was looking for was a way to destroy life (as we know it). Would carpet-nuking with Neutron bombs (or a better (reasonably feasible) solution*?) destroy surface/readily available insects, pollen, spores, bacteria and virii? How many would I need per square km?

  • reasonably feasible; Serban points to an answer requiring 4,200x 1001kg antimatter bombs (admittedly to scour the whole surface of the planet)... which is several orders of magnitude more antimatter than humans have managed to produce so far...

Yes, some of these exist in deep areas, but I'm just asking about sterilizing the surface, not making the whole planet uninhabitable. And preferably with minimal side-effects, ie: trying not to push the whole planet into nuclear winter if it can be avoided.

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    $\begingroup$ Voting to close as 'too broad'. For any of those groups of life (insects, pollen, spores, bacteria and virii) the answers are different and a lot of information can be found by just Googling (e.g. viruses). I suggest you do your homework first (that includes looking up radiation levels from atomic blasts) and then ask a more specific question. Focus on virii and pollen, they are the most radiation resistant. $\endgroup$ – user3106 Feb 17 '15 at 10:31
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    $\begingroup$ And if this question survives downvotes give it a better title. $\endgroup$ – user3106 Feb 17 '15 at 10:32
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    $\begingroup$ This answer might be relevant $\endgroup$ – Serban Tanasa Feb 17 '15 at 12:13
  • $\begingroup$ Malevil by Rober merle explores world after such war in Europe. Hint: life is tenacious and plenty of life survived - but situation is dire. $\endgroup$ – Peter M. - stands for Monica Feb 17 '15 at 13:54
  • $\begingroup$ Remember that some of the things you name are FAR more radiation-resistant than a human. $\endgroup$ – Loren Pechtel Feb 19 '15 at 3:31

Carpet nuking with regular nuclear bombs would be better, but even that wouldn't destroy all life.

Why not neutron bombs?

Neutron bombs don't emit deeply penetrating radiation in particularly large quantities. They put out lots of neutron radiation, which is incredibly deadly to living beings, but neutron radiation won't penetrate deeply though compounds containing hydrogen, like water. Moist soil or lakes will block the radiation from affecting deeply buried or bottom dwelling creatures.

How about regular nukes?

The heat, gamma radiation, and pressure given off by a conventional nuclear blast will be better at penetrating these things, but even it won't kill off all life. Bacteria exist kilometers under ground, where they eat trace amounts of elements like iron and sulfur to survive. It's estimated that these extremophiles, known as endoliths, can survive up to 7km below the bottom of the ocean, and to temperatures up to around 120 degrees Celsius. To destroy all life, you're going to need something that can effectively liquefy the surface of the Earth. I'm not sure what type of weapon will be able to do that, though crashing the moon into the Earth comes to mind as a possible method.


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