# What does 'ground zero' mean? **URL:** \ **Category:** Factual Questions\ **Created:** [August 29, 2001, 10:05am UTC](https://boards.straightdope.com/t/what-does-ground-zero-mean/78673 "2001-08-29T10:05:41Z")\ **Posts on this page:** 14\ **Page:** 1
**Author:** ![Galerion](https://avatars.discourse-cdn.com/v4/letter/g/858c86/32.png) [@Galerion](https://boards.straightdope.com/u/Galerion)\ **Post date:** [August 29, 2001, 10:05am UTC](https://boards.straightdope.com/t/what-does-ground-zero-mean/78673/1 "2001-08-29T10:05:41Z")
I’m from Sweden, and would like to know… ---
**Author:** ![sewalk](https://avatars.discourse-cdn.com/v4/letter/s/b3f665/32.png) [@sewalk](https://boards.straightdope.com/u/sewalk)\ **Post date:** [August 29, 2001, 10:39am UTC](https://boards.straightdope.com/t/what-does-ground-zero-mean/78673/2 "2001-08-29T10:39:08Z")
Traditionally, it means the point at which a nuclear bomb is detonated. ---
**Author:** ![SPOOFE](https://avatars.discourse-cdn.com/v4/letter/s/c5a1d2/32.png) [@SPOOFE](https://boards.straightdope.com/u/SPOOFE)\ **Post date:** [August 29, 2001, 10:41am UTC](https://boards.straightdope.com/t/what-does-ground-zero-mean/78673/3 "2001-08-29T10:41:22Z")
Or any bomb, for that matter. It’s also used to describe an area/entity that is affected most by a phenomenon/occurence. ---
**Author:** ![Galerion](https://avatars.discourse-cdn.com/v4/letter/g/858c86/32.png) [@Galerion](https://boards.straightdope.com/u/Galerion)\ **Post date:** [August 29, 2001, 10:54am UTC](https://boards.straightdope.com/t/what-does-ground-zero-mean/78673/4 "2001-08-29T10:54:13Z")
Thanks! ---
**Author:** ![Triskadecamus](https://avatars.discourse-cdn.com/v4/letter/t/b19c9b/32.png) [@Triskadecamus](https://boards.straightdope.com/u/Triskadecamus)\ **Post date:** [August 29, 2001, 11:55am UTC](https://boards.straightdope.com/t/what-does-ground-zero-mean/78673/5 "2001-08-29T11:55:29Z")
A minor nit pick, for the literal minded: Ground Zero is the point on the ground, or surface directly below the detonation point of a nuclear weapon. A difference, which is trivial to someone standing there, but important to the total effective blast produced. ## Tris " It is when I struggle to be brief that I become obscure." ~ Horace ---
**Author:** ![\_Twitch](https://avatars.discourse-cdn.com/v4/letter/_/3d9bf3/32.png) [@\_Twitch](https://boards.straightdope.com/u/_Twitch)\ **Post date:** [August 29, 2001, 11:59am UTC](https://boards.straightdope.com/t/what-does-ground-zero-mean/78673/6 "2001-08-29T11:59:08Z")
Nuclear weapons are set either to “ground burst” or “air burst”. Ground burst weapons explode on impact with the ground and ground zero in this case is the point of impact. Air burst weapons do far more damage. They are set to explode above the target. Height is dependant on the relative strength of the weapon. Ground zero is the point directly below the point of explosion. ---
**Author:** ![Darqangelle](https://avatars.discourse-cdn.com/v4/letter/d/ecccb3/32.png) [@Darqangelle](https://boards.straightdope.com/u/Darqangelle)\ **Post date:** [August 29, 2001, 3:16pm UTC](https://boards.straightdope.com/t/what-does-ground-zero-mean/78673/7 "2001-08-29T15:16:40Z")
“Vapour central” ---
**Author:** ![Dinsdale](https://avatars.discourse-cdn.com/v4/letter/d/97f17d/32.png) [@Dinsdale](https://boards.straightdope.com/u/Dinsdale)\ **Post date:** [August 29, 2001, 3:24pm UTC](https://boards.straightdope.com/t/what-does-ground-zero-mean/78673/8 "2001-08-29T15:24:31Z")
I thought it was the end product after **Olentzero** fell into a big mortar and pestle. On that subject, did you hear what happened to the sausage maker who backed into his meat grinder? He got a little behind in his work. Or the optometrist who fell into his lens grinder and made a spectacle of himself? (ducks and covers.) ---
**Author:** ![Dinsdale](https://avatars.discourse-cdn.com/v4/letter/d/97f17d/32.png) [@Dinsdale](https://boards.straightdope.com/u/Dinsdale)\ **Post date:** [August 29, 2001, 3:30pm UTC](https://boards.straightdope.com/t/what-does-ground-zero-mean/78673/9 "2001-08-29T15:30:48Z")
> [@](#): > > \*Originally posted by _Twitch_ \* > \*\*Nuclear weapons are set either to “ground burst” or “air burst”. Ground burst weapons explode on impact with the ground and ground zero in this case is the point of impact. > Air burst weapons do far more damage. They are set to explode above the target. Height is dependant on the relative strength of the weapon. Ground zero is the point directly below the point of explosion. \*\* Drawing upon my remote college days studying international relations, with an emphasis on nuclear policy and such recent developments as the SALT treaty (yes, I AM that old!): I believe ground and air burst serve different purposes. Ground burst would be best at destroying hardened targets such as silos and command centers. Necessary in a first strike. Air bursts spread their heat, pulse, and radioactivity over a greater area, resulting in a larger immediate area of damage. Such as over a city, or massed troops. But back in the favor of ground burst, they spew more radioactive dirt and crap into the air, providing the gift of death that keeps on giving as the wind blows. Now why couldn’t I have chosen something happier and more useful to study? ---
**Author:** ![slortar](https://avatars.discourse-cdn.com/v4/letter/s/6bbea6/32.png) [@slortar](https://boards.straightdope.com/u/slortar)\ **Post date:** [August 29, 2001, 4:59pm UTC](https://boards.straightdope.com/t/what-does-ground-zero-mean/78673/10 "2001-08-29T16:59:21Z")
If you’re curious, have a decent 'net connection and are somewhat morbid, there’s a whole hell of a lot of atomic test footage available for download at [http://archive.org](http://archive.org). ---
**Author:** ![DaveRaver](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/daveraver/32/1078_2.png) [@DaveRaver](https://boards.straightdope.com/u/DaveRaver)\ **Post date:** [September 21, 2001, 2:55am UTC](https://boards.straightdope.com/t/what-does-ground-zero-mean/78673/11 "2001-09-21T02:55:46Z")
It’s interesting that this question was asked just a couple of weeks before the World Trade Center attack. Time to investigate Sweden. ---
**Author:** ![squeegee](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/squeegee/32/14537_2.png) [@squeegee](https://boards.straightdope.com/u/squeegee)\ **Post date:** [September 21, 2001, 4:39am UTC](https://boards.straightdope.com/t/what-does-ground-zero-mean/78673/12 "2001-09-21T04:39:45Z")
To get back to the OP, _why_ is it called ‘ground zero’? Is there a ‘ground 4’ (presumably further away from the blast) ? ---
**Author:** ![AWB](https://avatars.discourse-cdn.com/v4/letter/a/bb73d2/32.png) [@AWB](https://boards.straightdope.com/u/AWB)\ **Post date:** [September 21, 2001, 4:47am UTC](https://boards.straightdope.com/t/what-does-ground-zero-mean/78673/13 "2001-09-21T04:47:08Z")
> [@](#): > > \*Originally posted by squeegee \* > \*\*To get back to the OP, _why_ is it called ‘ground zero’? > > Is there a ‘ground 4’ (presumably further away from the blast) ? \*\* “Ground” because it’s on the ground. “Zero” because it’s zero distance from the blast center. “Ground Four” could mean four miles, kilometers, furlongs, light-years, microns. Since they’re not definitive, the term “Ground” plus a non-zero number isn’t used. ---
**Author:** ![Chez\_Guevara](https://avatars.discourse-cdn.com/v4/letter/c/aeb1de/32.png) [@Chez\_Guevara](https://boards.straightdope.com/u/Chez_Guevara)\ **Post date:** [September 21, 2001, 5:30am UTC](https://boards.straightdope.com/t/what-does-ground-zero-mean/78673/14 "2001-09-21T05:30:29Z")
Ground zero, according to _Cassell’s Dictionary of Slang_, is also defined as _the basic position, the start, the essentials_, and dates from the 1950’s. This is a UK publication.