Support Your Local Volcano

[Orca]

We took a trip up to Mount St. Helens this weekend. I have visited the mountain a few times over the years. I was too young to remember the eruption, but I do have memories of the mountain from my childhood, visiting 10ish years afterward. It seemed so 'otherworldly,' still covered in ash. Then to see the green grasses and small trees returning when I visited in my 20s. And now, returning in my 40s to see forests taking root. It's been fascinating to observe the area change over the years.

South face

North face, from Johnston Ridge Observatory

[orin stepanek]

I sometimes wonder if any or how much of that mountain blew off into space!??

[Chris Peterson]

I sometimes wonder if any or how much of that mountain blew off into space!?? :shock: :mrgreen:

Pretty much the only mass that the Earth loses to space is hydrogen and helium. Not dust. So while a few molecules that used to be part of the mountain might ultimately be lost, in terms of the total mass that was blown off the mountain, we can consider the amount sent into space to essentially be zero.

[neufer]

I sometimes wonder if any or how much of that mountain blew off into space!??

• All of the material essentially emulated chemical bullets/single stage rockets.
  
  Chemical bullets/single stage rockets do not attain (11 km/s) escape velocity .

THE FIREBALL OF PRISCILLA shot fired on 6/24/57 as a part of Operation Plumbbob

---

<<In 1956, Dr Robert Brownlee, from Los Alamos National Laboratory in New Mexico, was asked to examine whether nuclear detonations could be conducted underground. The first subterranean test was the nuclear device known as Pascal A, which was lowered down a 150 m borehole. However, the detonated yield turned out to be 50,000 times greater than anticipated, creating a jet of fire that shot hundreds of feet into the sky.

During the Pascal-B nuclear test, of August 1957, a 900-kilogram steel plate cap (a piece of armor plate) was welded over the borehole to contain the nuclear blast even though Brownlee predicted it would not work. When Pascal-B was detonated, the blast went straight up the test shaft, launching the cap into the atmosphere at a speed of more than 66 km/s. The plate was never found. Scientists believe compression heating caused the cap to vaporize as it sped through the atmosphere. A high-speed camera, which took one frame per millisecond, was focused on the borehole because studying the velocity of the plate was deemed scientifically interesting. After the detonation, the plate appeared in only one frame, but this was enough to make an estimation of its speed. Dr. Brownlee joked the best estimate of the cover's speed from the photographic evidence was it was "going like a bat!" Brownlee estimated that the explosion, combined with the specific design of the shaft, could accelerate the plate to approximately six times Earth's escape velocity. In 2015 Dr. Brownlee said, "I have no idea what happened to the cap, but I always assumed that it was probably vaporized before it went into space." Later calculations made during 2019 (although with unconfirmed veracity), on the question of the survivability of the cap necessary to reach outer space are strongly in favor of its vaporization.>>

[Chris Peterson]

I sometimes wonder if any or how much of that mountain blew off into space!?? :shock: :mrgreen:

• All of the material essentially emulated chemical bullets/single stage rockets.
  
  Chemical bullets/single stage rockets do not attain (11 km/s) escape velocity .

While that is certainly true, it isn't strictly necessary for material to need to reach escape velocity immediately upon leaving the surface. Small particles can be carried aerodynamically into the upper atmosphere, where they could be transported out of Earth's gravitational well by the solar wind. Of course, the percentage of the ejected volcanic mass that would experience this is vanishingly small, but likely greater than zero.

[neufer]

I sometimes wonder if any or how much of that mountain blew off into space!??

• All of the material essentially emulated chemical bullets/single stage rockets.
  
  Chemical bullets/single stage rockets do not attain (11 km/s) escape velocity .

While that is certainly true, it isn't strictly necessary for material to need to reach escape velocity immediately upon leaving the surface. Small particles can be carried aerodynamically into the upper atmosphere, where they could be transported out of Earth's gravitational well by the solar wind. Of course, the percentage of the ejected volcanic mass that would experience this is vanishingly small, but likely greater than zero.

1) Small particles & expanding volcanic gases are highly unlikely to make it out of the stratosphere (even without horizontal expansion a chimney to the stratopause would require 750K gases to work).

2) Even if small volcanic particles were somehow to escape into the thermosphere
they would still be attracted back to Earth by almost 1 g of gravity.

3) Now, zodiacal light particles have to be less than 10 micrometers in diameter
for solar radiation pressure to cancel solar gravity (and thereby escape the solar system).

4) But said solar gravity only amounts to g/1650 (= 28g / 215²) at the distance of Earth

5) Hence a thermospheric volcanic particle would have to be less than 10 nanometers in diameter
for solar radiation pressure to cancel Earth's gravity in the thermosphere (and, thereby, escape Earth).

[Chris Peterson]

• All of the material essentially emulated chemical bullets/single stage rockets.
  
  Chemical bullets/single stage rockets do not attain (11 km/s) escape velocity .

While that is certainly true, it isn't strictly necessary for material to need to reach escape velocity immediately upon leaving the surface. Small particles can be carried aerodynamically into the upper atmosphere, where they could be transported out of Earth's gravitational well by the solar wind. Of course, the percentage of the ejected volcanic mass that would experience this is vanishingly small, but likely greater than zero.

1) Small particles & expanding volcanic gases are highly unlikely to make it out of the stratosphere (even without horizontal expansion a chimney to the stratopause would require 750K gases to work).

2) Even if small volcanic particles were somehow to escape into the thermosphere
they would still be attracted back to Earth by almost 1 g of gravity.

3) Now, zodiacal light particles have to be less than 10 micrometers in diameter
for solar radiation pressure to cancel solar gravity (and thereby escape the solar system).

4) But said solar gravity only amounts to g/1650 (= 28g / 215²) at the distance of Earth :!:

5) Hence a thermospheric volcanic particle would have to be less than 10 nanometers in diameter
for solar radiation pressure to cancel Earth's gravity in the thermosphere (and, thereby, escape Earth).

I agree completely that very little would be ejected. But enough dust was produced that I think it borders on the impossible to suggest that none was- perhaps even particles somewhat larger than a few micrometers.

[Orca]

I sometimes wonder if any or how much of that mountain blew off into space!??

Orin, I'd bet that a far larger portion ended up in small glass jars, tucked away and forgotten in attics, than the few particles that might have left the planet!

[orin stepanek]

I sometimes wonder if any or how much of that mountain blew off into space!??

Orin, I'd bet that a far larger portion ended up in small glass jars, tucked away and forgotten in attics, than the few particles that might have left the planet!

! Ha! I'll bet some even have 'em on display in their gardens or maybe even in their dens!