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Meteor Explodes over Massachusetts

nbcboston.com

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Re: Meteor Explodes over Massachusetts

#51

Post by porkyhalal »

quuxplusone wrote: post #11
jojobas wrote: post #3

PSA: meteors have nothing to do with explosions. The shockwave comes from meteor's movement alone, the parts never move apart with any speed comparable to their common forward motion. A breakup will increase surface area and therefore kinetic energy to shockwave transfer efficiency, still not an explosion.

The Wikipedia article on "meteor air burst" has an explanation that basically matches yours, although they do use the word "explosion" to describe it. Which makes sense to me: whatever one chooses to call it, it's a nearly instantaneous spontaneous disassembly that is very bright, very hot, and very loud. https://en.wikipedia.org/wiki/Meteor_air_burst

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Re: Meteor Explodes over Massachusetts

#52

Post by porkyhalal »

Guestmodinfo wrote: post #27
jojobas wrote: post #3

PSA: meteors have nothing to do with explosions. The shockwave comes from meteor's movement alone, the parts never move apart with any speed comparable to their common forward motion. A breakup will increase surface area and therefore kinetic energy to shockwave transfer efficiency, still not an explosion.

You are correct in class 9 physics book in India we have a mention of supersonic planes producing a sonic "boom" so the suprsonic planes don't themselves explode but their fast movement makes the air produce the boom. So you were correct as far as I can tell. But meteors do get smaller and smaller due to extreme friction from air and they do break into several pieces so that can also add to the sound.

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Re: Meteor Explodes over Massachusetts

#53

Post by adrian_b »

1970-01-01 wrote: post #23
dredmorbius wrote: post #20

Earlier quoted context omitted.

jojobas and NASA's statements aren't contradictory. NASA states: "the fragmentation of the fireball unleashes large amounts of energy, which also generates a pressure wave that can produce a very loud boom, even shaking houses." Fragmentation of a fireball, whilst not explosive itself (the particles needn't diverge at a supersonic relative velocity) are nonetheless part of a supersonic / hypersonic particle field rel…

Your statement is not supported by, and is somewhat at odds with, physics. As described in this source, observed terminal brightening/"burst" of a bolide is tied to the body's material behavior (fragmentation, rapid lateral expansion, ablation), and not to a free-standing "deceleration shockwave" that exists independently of the body breaking up. https://adsabs.harvard.edu/full/2001ESASP.495..491R

Some meteors really explode, because water and other volatile substances contained in them transform from solids into high temperature gases that expand quickly and cause the explosion of the body.

This is the same like how many kinds of water containing things, e.g. raw meat, eggs, fruits, can explode in a microwave oven if the microwave power is too high.

The meteor bodies belong to several classes of chemical compositions. Some of them contain very little volatiles, and they are made either of iron alloy or of silicate rocks or of a mixture of iron alloy and silicate rocks. These do not explode, at most they fragment into many smaller bodies.

Other classes contain great amounts of volatiles, e.g. water, organic compounds and sulfur compounds, and they frequently explode, depending on their size, shape and trajectory, i.e. if there is enough time for the interior to be heated to high temperatures, causing the phase change of the volatiles to gases.

Re: Meteor Explodes over Massachusetts

#54

Post by adrian_b »

jojobas wrote: post #14
quuxplusone wrote: post #11

Earlier quoted context omitted.

The Wikipedia article on "meteor air burst" has an explanation that basically matches yours, although they do use the word "explosion" to describe it. Which makes sense to me: whatever one chooses to call it, it's a nearly instantaneous spontaneous disassembly that is very bright, very hot, and very loud. https://en.wikipedia.org/wiki/Meteor_air_burst

The speed scale for disassembly is nowhere near the forward speed; you never get anywhere close to 45 degree debris divergence angle. It's also, again, not the disassembly that causes it to be bright, hot and loud. Wikipedians can also be wrong.

Some meteors do explode.

The meteors made only of iron alloy and/or silicate rocks do not explode, but they may fragment into many smaller bodies.

The meteors that contain great amounts of volatile substances (water, carbon compounds and sulfur compounds) may explode if the interior becomes hot enough to convert the volatiles into gases. When such a meteor rich in volatiles fragments, some of the fragments may explode, while others may reach the surface of the Earth intact.

Re: Meteor Explodes over Massachusetts

#55

Post by csiegert »

mhalle wrote: post #24

I have a Birdweather puck ( https://birdweather.com ) that listens for birds in our backyard in suburban Boston. It also measures sound pressure level (30 second sample rate). Our puck showed a 90.8dB sound level compared to a 55dB baseline. We thought a tree had hit the house because of the double boom. That was a repeated observation across all the local social media groups. The local UPS driver, who was outside at…

> Interesting this also happened in South Carolina and Ohio within the past few months.

Sounds like the beginning of an alien invasion movie. Sleeper ships buried themselves into every state. Waiting for the mother ship to arrive.

Re: Meteor Explodes over Massachusetts

#56

Post by x______________ »

adrian_b wrote: post #53
1970-01-01 wrote: post #23

Earlier quoted context omitted.

Your statement is not supported by, and is somewhat at odds with, physics. As described in this source, observed terminal brightening/"burst" of a bolide is tied to the body's material behavior (fragmentation, rapid lateral expansion, ablation), and not to a free-standing "deceleration shockwave" that exists independently of the body breaking up. https://adsabs.harvard.edu/full/2001ESASP.495..491R

Some meteors really explode, because water and other volatile substances contained in them transform from solids into high temperature gases that expand quickly and cause the explosion of the body. This is the same like how many kinds of water containing things, e.g. raw meat, eggs, fruits, can explode in a microwave oven if the microwave power is too high. The meteor bodies belong to several classes of chemical comp…

Thank you for the clarity so far down in the responses.

Meteors and eggs do not normally explode, but under the right circumstances.. Boom!

Re: Meteor Explodes over Massachusetts

#57

Post by bmelton »

jojobas wrote: post #8
margalabargala wrote: post #7

Earlier quoted context omitted.

PSA: The word "explosion" has multiple definitions, plenty of which are actually quite reasonable to apply to meteors! It can refer to the sound alone, for example. The people reporting an explosion in Massachusetts were not incorrect! It would however, be incorrect to claim that the meteor had noting to do with explosions.

No? There is no violent expansion or bursting, even if the sound is similar. It is as much an explosion as a supersonic jet passing by, and that is not much. The term makes people think atmospheric heating causes an actual steam explosion and that's the source of shockwave, which can't be further from truth.

Meteor Chelyabinsk suffered catastrophic fragmentation, a rapid, violent release of energy accompanied by a pressure wave with debris, which would satisfy the definition of an explosion (an in fact the energy released was equivalent to 400-500 kilotons of TNT.)

Re: Meteor Explodes over Massachusetts

#58

Post by thombat »

csiegert wrote: post #55
mhalle wrote: post #24

I have a Birdweather puck ( https://birdweather.com ) that listens for birds in our backyard in suburban Boston. It also measures sound pressure level (30 second sample rate). Our puck showed a 90.8dB sound level compared to a 55dB baseline. We thought a tree had hit the house because of the double boom. That was a repeated observation across all the local social media groups. The local UPS driver, who was outside at…

> Interesting this also happened in South Carolina and Ohio within the past few months. Sounds like the beginning of an alien invasion movie. Sleeper ships buried themselves into every state. Waiting for the mother ship to arrive.

Feels like a proper movie that political boundaries like state lines would be significant for all concerned. One meteor for Rhode Island, one for Texas... Any questions? (Asks the alien overlord of his minions in his crisp British accent)

Re: Meteor Explodes over Massachusetts

#59

Post by SideburnsOfDoom »

csiegert wrote: post #55
mhalle wrote: post #24

I have a Birdweather puck ( https://birdweather.com ) that listens for birds in our backyard in suburban Boston. It also measures sound pressure level (30 second sample rate). Our puck showed a 90.8dB sound level compared to a 55dB baseline. We thought a tree had hit the house because of the double boom. That was a repeated observation across all the local social media groups. The local UPS driver, who was outside at…

> Interesting this also happened in South Carolina and Ohio within the past few months. Sounds like the beginning of an alien invasion movie. Sleeper ships buried themselves into every state. Waiting for the mother ship to arrive.

> Interesting this also happened in South Carolina and Ohio within the past few months.

Not that interesting, apparently this scale of meteor happens on average multiple times a year, just not usually over such an urban area.

The 2013 Chelyabinsk meteor (1) was larger and caused ground damage and injuries from e.g. flying glass from broken windows.

> Sounds like the beginning of an alien invasion movie. Sleeper ships buried themselves into every state.

Based on the last Alien invasion book that I read (2), it would rather start with air bursting the bioweapons, spreading the plagues to weaken us. Which ah, also fits this incident.

1) https://en.wikipedia.org/wiki/Chelyabinsk_meteor

2) https://en.wikipedia.org/wiki/The_War_Against_the_Chtorr https://en.wikipedia.org/wiki/The_Screwfly_Solution

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