What Size Space Bombs Would Detonate in Midair Based on Their Composition?

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Discussion Overview

The discussion centers around the concept of "space bombs," specifically focusing on the conditions under which these objects, composed of rock, metal, or ice, might detonate in midair as they enter Earth's atmosphere. Participants explore the implications of material composition and size on the altitude of detonation, referencing historical events like the Tunguska explosion.

Discussion Character

  • Debate/contested
  • Conceptual clarification
  • Exploratory

Main Points Raised

  • Some participants describe the Tunguska event as an example of an air burst, where a space bomb detonated without leaving a crater.
  • There is contention over the term "space bomb," with some arguing it is an inappropriate label for natural phenomena like meteors and suggesting alternatives such as "bolide."
  • One participant mentions a simulation tool, "Impact: Earth!", which could help visualize the effects of such impacts.
  • Another participant notes that a stony object around 50 meters across is expected to detonate at altitudes of 5-6 miles, raising questions about the size and behavior of smaller objects.
  • Questions are raised about why smaller meteors do not always burn up in the atmosphere and whether they are remnants of larger objects that exploded at higher altitudes.
  • Some participants express uncertainty about the specifics of diameters for non-stony objects and the details of atmospheric entry dynamics.

Areas of Agreement / Disagreement

Participants do not reach consensus on the terminology used to describe these objects, with some advocating for more scientifically accepted terms while others prefer a more conversational approach. The discussion remains unresolved regarding the specifics of how different materials behave during atmospheric entry.

Contextual Notes

There are limitations in the discussion regarding assumptions about the behavior of different materials and the lack of definitive answers on the size and composition of objects that detonate at specific altitudes.

Who May Find This Useful

Readers interested in meteoric phenomena, impact events, and the dynamics of atmospheric entry may find the discussion relevant.

JohnWDailey
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On June 30, 1908, the remote Siberian region of Tunguska made headline news when an explosion knocked down 80 million trees in an area of only 770 square miles. The mystery was that there was no crater, which led to the assumption that the space bomb responsible for the catastrophe detonated in midair--a behavior scientists call an "air burst". The explosion must have happened four to six miles above the actual lands of Tunguska.

We know that the space bombs that visit Earth, be they comets or asteroids, comprise of any of three materials--rock, metal or ice, and each reacts differently to the rising pressure associated with descending to the Earth's atmosphere at high speed.

Let's say that we have a scenario where a space bomb is due to explode four to six miles above the Earth and duplicated it three times so that we have one scenario where the space bomb is made of rock, another of metal and one more of ice. At an altitude of four to six miles, what is the largest space bomb from each scenario that would fall down before being detonated in midair?
 
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"Space bomb"? This sounds artificial. This is an entirely natural phenomenon.
 
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JohnWDailey said:
On June 30, 1908, the remote Siberian region of Tunguska made headline news when an explosion knocked down 80 million trees in an area of only 770 square miles. The mystery was that there was no crater, which led to the assumption that the space bomb responsible for the catastrophe detonated in midair--a behavior scientists call an "air burst". The explosion must have happened four to six miles above the actual lands of Tunguska.

We know that the space bombs that visit Earth, be they comets or asteroids, comprise of any of three materials--rock, metal or ice, and each reacts differently to the rising pressure associated with descending to the Earth's atmosphere at high speed.

Let's say that we have a scenario where a space bomb is due to explode four to six miles above the Earth and duplicated it three times so that we have one scenario where the space bomb is made of rock, another of metal and one more of ice. At an altitude of four to six miles, what is the largest space bomb from each scenario that would fall down before being detonated in midair?

hmmm... I can't remember how to figure that out. But I did find a very fun app for that last year: Impact: Earth! A meteor/comet impact simulator [PF]

Devilishly fun.
 
"Space bomb" is anybody from space that detonates on contact with Earth, be it on the surface or the atmosphere. If you want to be conversational, be general. "Meteor" and "meteorite" won't do because such changes in name implies a change in mechanics and chemistry, which there really isn't.
 
JohnWDailey said:
"Space bomb" is anybody from space that detonates on contact with Earth, be it on the surface or the atmosphere.

not in any reliable scientific literature I have ever read. please don't use this term ... yet another garbage pop-science termDave
 
You know, it doesn't really hurt to be conversational.
 
JohnWDailey said:
"Meteor" and "meteorite" won't do because such changes in name implies a change in mechanics and chemistry, which there really isn't.

The term used by astronomers is generally "bolide" or "superbolide", though there is no official term from the IAU. See here: https://en.wikipedia.org/wiki/Bolide

JohnWDailey said:
Let's say that we have a scenario where a space bomb is due to explode four to six miles above the Earth and duplicated it three times so that we have one scenario where the space bomb is made of rock, another of metal and one more of ice. At an altitude of four to six miles, what is the largest space bomb from each scenario that would fall down before being detonated in midair?

According to the table on this wiki page, a stony object 50 meters across detonates around 5-6 miles in the air. Based on the table, it looks like the altitude depends on the diameter of the object, so a larger object would explode closer to the ground. I'm guessing the diameter of the object would need to be about 55 meters or so do get an explosion at 4-5 miles in altitude. I don't know what the diameter might be for non-stony objects.
 
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Drakkith said:
According to the table on this wiki page, a stony object 50 meters across detonates around 5-6 miles in the air. Based on the table, it looks like the altitude depends on the diameter of the object, so a larger object would explode closer to the ground.

Begs the question... Why don't all small ones burn up very high up? How come so many make it to the ground and are picked up in places like Antarctica? Are all small ones the result of a bigger one exploding high up?
 
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CWatters said:
Begs the question... Why don't all small ones burn up very high up? How come so many make it to the ground and are picked up in places like Antarctica? Are all small ones the result of a bigger one exploding high up?

I assume they were much bigger, but most of the material was vaporized during the travel through the atmosphere. I'm no expert though, so I have no idea about all the details.
 
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Drakkith said:
I assume they were much bigger, but most of the material was vaporized during the travel through the atmosphere. I'm no expert though, so I have no idea about all the details.

@D H struck me as the most "experty" person regarding meteors, here at the forum.
He taught me a lesson or two about the Tunguska event.

:bow:
 
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JohnWDailey said:
You know, it doesn't really hurt to be conversational.
I'm not sure about that. Sloppy language can lead to massive misunderstandings and "it really doesn't hurt" to learn and to use the general accepted terms in a technical argument. If a symbol in a mathematical procedure is suddenly changed then you could expect a seriously wrong answer - likewise with a change of words.
 
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  • #14
bolide. A word of Greek origin meaning ball or quasi-spherical object. A round rock is a bolide
 

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