Vacuum of Space Question
$begingroup$
The vacuum of space is incredibly powerful
1 X 10 ^-17 torr
I’m editing my question to reflect the vacuum between the earth and the moon 1 X 10 ^-11 torr
How can such a vacuum in close proximity to the earth coexist with the open system of earth’s atmosphere whereby debris from space can enter in?
Apparently according to uhoh the vacuum of space has a gradient. I wonder how that proports to the second law of thermodynamics.
https://web.pa.msu.edu/courses/2014fall/PHY451/Lectures/Vacuum.pdf
https://web.pa.msu.edu/courses/2014fall/PHY451/Lectures/Vacuum.pdf
cosmology atmosphere space vacuum
New contributor
$endgroup$
add a comment |
$begingroup$
The vacuum of space is incredibly powerful
1 X 10 ^-17 torr
I’m editing my question to reflect the vacuum between the earth and the moon 1 X 10 ^-11 torr
How can such a vacuum in close proximity to the earth coexist with the open system of earth’s atmosphere whereby debris from space can enter in?
Apparently according to uhoh the vacuum of space has a gradient. I wonder how that proports to the second law of thermodynamics.
https://web.pa.msu.edu/courses/2014fall/PHY451/Lectures/Vacuum.pdf
https://web.pa.msu.edu/courses/2014fall/PHY451/Lectures/Vacuum.pdf
cosmology atmosphere space vacuum
New contributor
$endgroup$
add a comment |
$begingroup$
The vacuum of space is incredibly powerful
1 X 10 ^-17 torr
I’m editing my question to reflect the vacuum between the earth and the moon 1 X 10 ^-11 torr
How can such a vacuum in close proximity to the earth coexist with the open system of earth’s atmosphere whereby debris from space can enter in?
Apparently according to uhoh the vacuum of space has a gradient. I wonder how that proports to the second law of thermodynamics.
https://web.pa.msu.edu/courses/2014fall/PHY451/Lectures/Vacuum.pdf
https://web.pa.msu.edu/courses/2014fall/PHY451/Lectures/Vacuum.pdf
cosmology atmosphere space vacuum
New contributor
$endgroup$
The vacuum of space is incredibly powerful
1 X 10 ^-17 torr
I’m editing my question to reflect the vacuum between the earth and the moon 1 X 10 ^-11 torr
How can such a vacuum in close proximity to the earth coexist with the open system of earth’s atmosphere whereby debris from space can enter in?
Apparently according to uhoh the vacuum of space has a gradient. I wonder how that proports to the second law of thermodynamics.
https://web.pa.msu.edu/courses/2014fall/PHY451/Lectures/Vacuum.pdf
https://web.pa.msu.edu/courses/2014fall/PHY451/Lectures/Vacuum.pdf
cosmology atmosphere space vacuum
cosmology atmosphere space vacuum
New contributor
New contributor
edited 21 mins ago
Autodidact
New contributor
asked 1 hour ago
AutodidactAutodidact
1064
1064
New contributor
New contributor
add a comment |
add a comment |
1 Answer
1
active
oldest
votes
$begingroup$
update: This answer was written before the question was modified. I've tried to explain where a value like 10-17 Torr for deep space might come from, but it's since been dropped in lieu of 10^-11 Torr at the Moon, which is probably a better way to formulate the question.
I think the answer is the same, two points very far away can have very different pressures. They can coexist in the same solar system, just not right next to each other. I think "Why doesn't the Moon have at least a small atmosphere?" could also be an excellent, but very different question.
In a comment the OP links to the presentation VACUUM (There’s nothing to it… ) written from the perspective of an engineer in the semiconductor manufacturing industry.
Slide 6 gives examples of vacuum levels in different situations:
Going down:
- Low vacuum: 760 Torr to 1 x 10-3 Torr
- Vacuum cleaner: to 600 Torr
- Thermos bottle 10-3 Torr
- High vacuum: 10-3 to 10-9 Torr
- Electron microscope
- Ion Implanter
– Evaporator
– Sputterer
- Ultra high vacuum: 10-9 to 10-12 Torr
- CERN LHC: 1 x 10-10 Torr
- Moon’s surface: 1 x 10-11 Torr
- Deep Space 1 x 10-17 Torr = 0.000,000,000,000,000,01 Torr
So we can see that the value of 1 x 10-17 Torr is associated with a place in "Deep Space" which is (probably) beyond that of the Moon.
Let's see if we can figure out where the author is getting that number.
According to the Wikipedia article on the interstellar medium (space between stars, far away from solar systems and other things):
In all phases, the interstellar medium is extremely tenuous by terrestrial standards. In cool, dense regions of the ISM, matter is primarily in molecular form, and reaches number densities of 106 molecules per cm3 (1 million molecules per cm3). In hot, diffuse regions of the ISM, matter is primarily ionized, and the density may be as low as 10−4 ions per cm3. Compare this with a number density of roughly 1019 molecules per cm3 for air at sea level, and 1010 molecules per cm3 (10 billion molecules per cm3) for a laboratory high-vacuum chamber.
It is harder to talk about pressure than density because pressure is related to both number density and temperature. The atmosphere is more than 10x hotter than interstellar medium, so let's look for a number density ratio of 1/10 of 1000 Torr versus 10^-17 torr, or a ratio of 10^19.
If (according to Wikipedia) Earth's atmosphere has a density of 10^19 per cm^3, we're looking for a density of 1 per cm^3. Checking Wikipedia we can see that there are components of the interstellar medium with number densities between 10^6 and 10^-4.
It looks like the value in the presentation a rough ballpark estimate, but isn't off by more than a handful of orders of magnitude ;-)
How can such a vacuum coexist with the open system of earth’s atmosphere whereby debris from space can enter in?
While these two pressures can coexist in the same universe, they don't coexist in proximity at all. The interstellar medium is very, very far away from Earth's atmosphere, on the order of a lightyear.
Gravity keeps Earth's atmosphere nearby Earth, the solar system has gas produced by (and attracted by) the Sun's gravity. In interstellar space, there just isn't any source of gas, and what might have been there at one time has moved away, towards sources of gravity, over billions of years.
$endgroup$
$begingroup$
Thank you for your response. Are you disputing the pressure on the moon also? Because if the pressure is out by a handful of magnitudes certainly between the moon and earth’s atmosphere there exist a vacuum of some sort at least as weak as a dyson vacuum cleaner. The notion that gravity holds the atmosphere in place but still is weak enough to allow gases to stratify depending on density or pressure is very difficult to wrap my head around. Not to mention that pressure requires something to press onto. What is the atmosphere pressing onto? The vacuum?
$endgroup$
– Autodidact
48 mins ago
$begingroup$
@Autodidact I have not disputed anything. I'm in general agreement with the powerpoint; within several orders of magnitude at least. The word "coexist" makes your question difficult to answer because you don't explain what you mean. They can coexist in the same universe, but not close to each other. I think a question about how the atmosphere ends up stratified in pressure due to gravity is a great one, but probably is better to ask in Earth Science SE or Physics SE.
$endgroup$
– uhoh
42 mins ago
1
$begingroup$
@Autodidact You may find several questions and answers like that in those sites already, best to read them before asking something that's been answered. Here is some related math, but there are probably better places to find a useful and head-wrappable explanation. en.wikipedia.org/wiki/Scale_height
$endgroup$
– uhoh
42 mins ago
1
$begingroup$
Thank you for the link. If this question is not asked in the correct stack, my sincerest apologies. Also my edit was not intended as a moving target, I didn’t want it dismissed. As for the atmosphere pressure, while the link provides a distance it doesn’t explain my inquiry, what is it pressing upon to generate the distance? That is a question to which I cannot seem to find an answer to. Gravity seems to be the answer but it’s powers are conflicting as I’ve pointed out. It’s sufficiently strong to resist a vacuum of 10^-11 but weak enough to let gas particles up 8.5 km up into the atmosphere.
$endgroup$
– Autodidact
23 mins ago
1
$begingroup$
The Moon kind of does have an atmosphere, but it's very thin, and its total mass is under 10 tonnes. See en.wikipedia.org/wiki/Atmosphere_of_the_Moon
$endgroup$
– PM 2Ring
16 mins ago
|
show 2 more comments
Your Answer
StackExchange.ifUsing("editor", function () {
return StackExchange.using("mathjaxEditing", function () {
StackExchange.MarkdownEditor.creationCallbacks.add(function (editor, postfix) {
StackExchange.mathjaxEditing.prepareWmdForMathJax(editor, postfix, [["$", "$"], ["\\(","\\)"]]);
});
});
}, "mathjax-editing");
StackExchange.ready(function() {
var channelOptions = {
tags: "".split(" "),
id: "514"
};
initTagRenderer("".split(" "), "".split(" "), channelOptions);
StackExchange.using("externalEditor", function() {
// Have to fire editor after snippets, if snippets enabled
if (StackExchange.settings.snippets.snippetsEnabled) {
StackExchange.using("snippets", function() {
createEditor();
});
}
else {
createEditor();
}
});
function createEditor() {
StackExchange.prepareEditor({
heartbeatType: 'answer',
autoActivateHeartbeat: false,
convertImagesToLinks: false,
noModals: true,
showLowRepImageUploadWarning: true,
reputationToPostImages: null,
bindNavPrevention: true,
postfix: "",
imageUploader: {
brandingHtml: "Powered by u003ca class="icon-imgur-white" href="https://imgur.com/"u003eu003c/au003e",
contentPolicyHtml: "User contributions licensed under u003ca href="https://creativecommons.org/licenses/by-sa/3.0/"u003ecc by-sa 3.0 with attribution requiredu003c/au003e u003ca href="https://stackoverflow.com/legal/content-policy"u003e(content policy)u003c/au003e",
allowUrls: true
},
noCode: true, onDemand: true,
discardSelector: ".discard-answer"
,immediatelyShowMarkdownHelp:true
});
}
});
Autodidact is a new contributor. Be nice, and check out our Code of Conduct.
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
StackExchange.ready(
function () {
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fastronomy.stackexchange.com%2fquestions%2f29832%2fvacuum-of-space-question%23new-answer', 'question_page');
}
);
Post as a guest
Required, but never shown
1 Answer
1
active
oldest
votes
1 Answer
1
active
oldest
votes
active
oldest
votes
active
oldest
votes
$begingroup$
update: This answer was written before the question was modified. I've tried to explain where a value like 10-17 Torr for deep space might come from, but it's since been dropped in lieu of 10^-11 Torr at the Moon, which is probably a better way to formulate the question.
I think the answer is the same, two points very far away can have very different pressures. They can coexist in the same solar system, just not right next to each other. I think "Why doesn't the Moon have at least a small atmosphere?" could also be an excellent, but very different question.
In a comment the OP links to the presentation VACUUM (There’s nothing to it… ) written from the perspective of an engineer in the semiconductor manufacturing industry.
Slide 6 gives examples of vacuum levels in different situations:
Going down:
- Low vacuum: 760 Torr to 1 x 10-3 Torr
- Vacuum cleaner: to 600 Torr
- Thermos bottle 10-3 Torr
- High vacuum: 10-3 to 10-9 Torr
- Electron microscope
- Ion Implanter
– Evaporator
– Sputterer
- Ultra high vacuum: 10-9 to 10-12 Torr
- CERN LHC: 1 x 10-10 Torr
- Moon’s surface: 1 x 10-11 Torr
- Deep Space 1 x 10-17 Torr = 0.000,000,000,000,000,01 Torr
So we can see that the value of 1 x 10-17 Torr is associated with a place in "Deep Space" which is (probably) beyond that of the Moon.
Let's see if we can figure out where the author is getting that number.
According to the Wikipedia article on the interstellar medium (space between stars, far away from solar systems and other things):
In all phases, the interstellar medium is extremely tenuous by terrestrial standards. In cool, dense regions of the ISM, matter is primarily in molecular form, and reaches number densities of 106 molecules per cm3 (1 million molecules per cm3). In hot, diffuse regions of the ISM, matter is primarily ionized, and the density may be as low as 10−4 ions per cm3. Compare this with a number density of roughly 1019 molecules per cm3 for air at sea level, and 1010 molecules per cm3 (10 billion molecules per cm3) for a laboratory high-vacuum chamber.
It is harder to talk about pressure than density because pressure is related to both number density and temperature. The atmosphere is more than 10x hotter than interstellar medium, so let's look for a number density ratio of 1/10 of 1000 Torr versus 10^-17 torr, or a ratio of 10^19.
If (according to Wikipedia) Earth's atmosphere has a density of 10^19 per cm^3, we're looking for a density of 1 per cm^3. Checking Wikipedia we can see that there are components of the interstellar medium with number densities between 10^6 and 10^-4.
It looks like the value in the presentation a rough ballpark estimate, but isn't off by more than a handful of orders of magnitude ;-)
How can such a vacuum coexist with the open system of earth’s atmosphere whereby debris from space can enter in?
While these two pressures can coexist in the same universe, they don't coexist in proximity at all. The interstellar medium is very, very far away from Earth's atmosphere, on the order of a lightyear.
Gravity keeps Earth's atmosphere nearby Earth, the solar system has gas produced by (and attracted by) the Sun's gravity. In interstellar space, there just isn't any source of gas, and what might have been there at one time has moved away, towards sources of gravity, over billions of years.
$endgroup$
$begingroup$
Thank you for your response. Are you disputing the pressure on the moon also? Because if the pressure is out by a handful of magnitudes certainly between the moon and earth’s atmosphere there exist a vacuum of some sort at least as weak as a dyson vacuum cleaner. The notion that gravity holds the atmosphere in place but still is weak enough to allow gases to stratify depending on density or pressure is very difficult to wrap my head around. Not to mention that pressure requires something to press onto. What is the atmosphere pressing onto? The vacuum?
$endgroup$
– Autodidact
48 mins ago
$begingroup$
@Autodidact I have not disputed anything. I'm in general agreement with the powerpoint; within several orders of magnitude at least. The word "coexist" makes your question difficult to answer because you don't explain what you mean. They can coexist in the same universe, but not close to each other. I think a question about how the atmosphere ends up stratified in pressure due to gravity is a great one, but probably is better to ask in Earth Science SE or Physics SE.
$endgroup$
– uhoh
42 mins ago
1
$begingroup$
@Autodidact You may find several questions and answers like that in those sites already, best to read them before asking something that's been answered. Here is some related math, but there are probably better places to find a useful and head-wrappable explanation. en.wikipedia.org/wiki/Scale_height
$endgroup$
– uhoh
42 mins ago
1
$begingroup$
Thank you for the link. If this question is not asked in the correct stack, my sincerest apologies. Also my edit was not intended as a moving target, I didn’t want it dismissed. As for the atmosphere pressure, while the link provides a distance it doesn’t explain my inquiry, what is it pressing upon to generate the distance? That is a question to which I cannot seem to find an answer to. Gravity seems to be the answer but it’s powers are conflicting as I’ve pointed out. It’s sufficiently strong to resist a vacuum of 10^-11 but weak enough to let gas particles up 8.5 km up into the atmosphere.
$endgroup$
– Autodidact
23 mins ago
1
$begingroup$
The Moon kind of does have an atmosphere, but it's very thin, and its total mass is under 10 tonnes. See en.wikipedia.org/wiki/Atmosphere_of_the_Moon
$endgroup$
– PM 2Ring
16 mins ago
|
show 2 more comments
$begingroup$
update: This answer was written before the question was modified. I've tried to explain where a value like 10-17 Torr for deep space might come from, but it's since been dropped in lieu of 10^-11 Torr at the Moon, which is probably a better way to formulate the question.
I think the answer is the same, two points very far away can have very different pressures. They can coexist in the same solar system, just not right next to each other. I think "Why doesn't the Moon have at least a small atmosphere?" could also be an excellent, but very different question.
In a comment the OP links to the presentation VACUUM (There’s nothing to it… ) written from the perspective of an engineer in the semiconductor manufacturing industry.
Slide 6 gives examples of vacuum levels in different situations:
Going down:
- Low vacuum: 760 Torr to 1 x 10-3 Torr
- Vacuum cleaner: to 600 Torr
- Thermos bottle 10-3 Torr
- High vacuum: 10-3 to 10-9 Torr
- Electron microscope
- Ion Implanter
– Evaporator
– Sputterer
- Ultra high vacuum: 10-9 to 10-12 Torr
- CERN LHC: 1 x 10-10 Torr
- Moon’s surface: 1 x 10-11 Torr
- Deep Space 1 x 10-17 Torr = 0.000,000,000,000,000,01 Torr
So we can see that the value of 1 x 10-17 Torr is associated with a place in "Deep Space" which is (probably) beyond that of the Moon.
Let's see if we can figure out where the author is getting that number.
According to the Wikipedia article on the interstellar medium (space between stars, far away from solar systems and other things):
In all phases, the interstellar medium is extremely tenuous by terrestrial standards. In cool, dense regions of the ISM, matter is primarily in molecular form, and reaches number densities of 106 molecules per cm3 (1 million molecules per cm3). In hot, diffuse regions of the ISM, matter is primarily ionized, and the density may be as low as 10−4 ions per cm3. Compare this with a number density of roughly 1019 molecules per cm3 for air at sea level, and 1010 molecules per cm3 (10 billion molecules per cm3) for a laboratory high-vacuum chamber.
It is harder to talk about pressure than density because pressure is related to both number density and temperature. The atmosphere is more than 10x hotter than interstellar medium, so let's look for a number density ratio of 1/10 of 1000 Torr versus 10^-17 torr, or a ratio of 10^19.
If (according to Wikipedia) Earth's atmosphere has a density of 10^19 per cm^3, we're looking for a density of 1 per cm^3. Checking Wikipedia we can see that there are components of the interstellar medium with number densities between 10^6 and 10^-4.
It looks like the value in the presentation a rough ballpark estimate, but isn't off by more than a handful of orders of magnitude ;-)
How can such a vacuum coexist with the open system of earth’s atmosphere whereby debris from space can enter in?
While these two pressures can coexist in the same universe, they don't coexist in proximity at all. The interstellar medium is very, very far away from Earth's atmosphere, on the order of a lightyear.
Gravity keeps Earth's atmosphere nearby Earth, the solar system has gas produced by (and attracted by) the Sun's gravity. In interstellar space, there just isn't any source of gas, and what might have been there at one time has moved away, towards sources of gravity, over billions of years.
$endgroup$
$begingroup$
Thank you for your response. Are you disputing the pressure on the moon also? Because if the pressure is out by a handful of magnitudes certainly between the moon and earth’s atmosphere there exist a vacuum of some sort at least as weak as a dyson vacuum cleaner. The notion that gravity holds the atmosphere in place but still is weak enough to allow gases to stratify depending on density or pressure is very difficult to wrap my head around. Not to mention that pressure requires something to press onto. What is the atmosphere pressing onto? The vacuum?
$endgroup$
– Autodidact
48 mins ago
$begingroup$
@Autodidact I have not disputed anything. I'm in general agreement with the powerpoint; within several orders of magnitude at least. The word "coexist" makes your question difficult to answer because you don't explain what you mean. They can coexist in the same universe, but not close to each other. I think a question about how the atmosphere ends up stratified in pressure due to gravity is a great one, but probably is better to ask in Earth Science SE or Physics SE.
$endgroup$
– uhoh
42 mins ago
1
$begingroup$
@Autodidact You may find several questions and answers like that in those sites already, best to read them before asking something that's been answered. Here is some related math, but there are probably better places to find a useful and head-wrappable explanation. en.wikipedia.org/wiki/Scale_height
$endgroup$
– uhoh
42 mins ago
1
$begingroup$
Thank you for the link. If this question is not asked in the correct stack, my sincerest apologies. Also my edit was not intended as a moving target, I didn’t want it dismissed. As for the atmosphere pressure, while the link provides a distance it doesn’t explain my inquiry, what is it pressing upon to generate the distance? That is a question to which I cannot seem to find an answer to. Gravity seems to be the answer but it’s powers are conflicting as I’ve pointed out. It’s sufficiently strong to resist a vacuum of 10^-11 but weak enough to let gas particles up 8.5 km up into the atmosphere.
$endgroup$
– Autodidact
23 mins ago
1
$begingroup$
The Moon kind of does have an atmosphere, but it's very thin, and its total mass is under 10 tonnes. See en.wikipedia.org/wiki/Atmosphere_of_the_Moon
$endgroup$
– PM 2Ring
16 mins ago
|
show 2 more comments
$begingroup$
update: This answer was written before the question was modified. I've tried to explain where a value like 10-17 Torr for deep space might come from, but it's since been dropped in lieu of 10^-11 Torr at the Moon, which is probably a better way to formulate the question.
I think the answer is the same, two points very far away can have very different pressures. They can coexist in the same solar system, just not right next to each other. I think "Why doesn't the Moon have at least a small atmosphere?" could also be an excellent, but very different question.
In a comment the OP links to the presentation VACUUM (There’s nothing to it… ) written from the perspective of an engineer in the semiconductor manufacturing industry.
Slide 6 gives examples of vacuum levels in different situations:
Going down:
- Low vacuum: 760 Torr to 1 x 10-3 Torr
- Vacuum cleaner: to 600 Torr
- Thermos bottle 10-3 Torr
- High vacuum: 10-3 to 10-9 Torr
- Electron microscope
- Ion Implanter
– Evaporator
– Sputterer
- Ultra high vacuum: 10-9 to 10-12 Torr
- CERN LHC: 1 x 10-10 Torr
- Moon’s surface: 1 x 10-11 Torr
- Deep Space 1 x 10-17 Torr = 0.000,000,000,000,000,01 Torr
So we can see that the value of 1 x 10-17 Torr is associated with a place in "Deep Space" which is (probably) beyond that of the Moon.
Let's see if we can figure out where the author is getting that number.
According to the Wikipedia article on the interstellar medium (space between stars, far away from solar systems and other things):
In all phases, the interstellar medium is extremely tenuous by terrestrial standards. In cool, dense regions of the ISM, matter is primarily in molecular form, and reaches number densities of 106 molecules per cm3 (1 million molecules per cm3). In hot, diffuse regions of the ISM, matter is primarily ionized, and the density may be as low as 10−4 ions per cm3. Compare this with a number density of roughly 1019 molecules per cm3 for air at sea level, and 1010 molecules per cm3 (10 billion molecules per cm3) for a laboratory high-vacuum chamber.
It is harder to talk about pressure than density because pressure is related to both number density and temperature. The atmosphere is more than 10x hotter than interstellar medium, so let's look for a number density ratio of 1/10 of 1000 Torr versus 10^-17 torr, or a ratio of 10^19.
If (according to Wikipedia) Earth's atmosphere has a density of 10^19 per cm^3, we're looking for a density of 1 per cm^3. Checking Wikipedia we can see that there are components of the interstellar medium with number densities between 10^6 and 10^-4.
It looks like the value in the presentation a rough ballpark estimate, but isn't off by more than a handful of orders of magnitude ;-)
How can such a vacuum coexist with the open system of earth’s atmosphere whereby debris from space can enter in?
While these two pressures can coexist in the same universe, they don't coexist in proximity at all. The interstellar medium is very, very far away from Earth's atmosphere, on the order of a lightyear.
Gravity keeps Earth's atmosphere nearby Earth, the solar system has gas produced by (and attracted by) the Sun's gravity. In interstellar space, there just isn't any source of gas, and what might have been there at one time has moved away, towards sources of gravity, over billions of years.
$endgroup$
update: This answer was written before the question was modified. I've tried to explain where a value like 10-17 Torr for deep space might come from, but it's since been dropped in lieu of 10^-11 Torr at the Moon, which is probably a better way to formulate the question.
I think the answer is the same, two points very far away can have very different pressures. They can coexist in the same solar system, just not right next to each other. I think "Why doesn't the Moon have at least a small atmosphere?" could also be an excellent, but very different question.
In a comment the OP links to the presentation VACUUM (There’s nothing to it… ) written from the perspective of an engineer in the semiconductor manufacturing industry.
Slide 6 gives examples of vacuum levels in different situations:
Going down:
- Low vacuum: 760 Torr to 1 x 10-3 Torr
- Vacuum cleaner: to 600 Torr
- Thermos bottle 10-3 Torr
- High vacuum: 10-3 to 10-9 Torr
- Electron microscope
- Ion Implanter
– Evaporator
– Sputterer
- Ultra high vacuum: 10-9 to 10-12 Torr
- CERN LHC: 1 x 10-10 Torr
- Moon’s surface: 1 x 10-11 Torr
- Deep Space 1 x 10-17 Torr = 0.000,000,000,000,000,01 Torr
So we can see that the value of 1 x 10-17 Torr is associated with a place in "Deep Space" which is (probably) beyond that of the Moon.
Let's see if we can figure out where the author is getting that number.
According to the Wikipedia article on the interstellar medium (space between stars, far away from solar systems and other things):
In all phases, the interstellar medium is extremely tenuous by terrestrial standards. In cool, dense regions of the ISM, matter is primarily in molecular form, and reaches number densities of 106 molecules per cm3 (1 million molecules per cm3). In hot, diffuse regions of the ISM, matter is primarily ionized, and the density may be as low as 10−4 ions per cm3. Compare this with a number density of roughly 1019 molecules per cm3 for air at sea level, and 1010 molecules per cm3 (10 billion molecules per cm3) for a laboratory high-vacuum chamber.
It is harder to talk about pressure than density because pressure is related to both number density and temperature. The atmosphere is more than 10x hotter than interstellar medium, so let's look for a number density ratio of 1/10 of 1000 Torr versus 10^-17 torr, or a ratio of 10^19.
If (according to Wikipedia) Earth's atmosphere has a density of 10^19 per cm^3, we're looking for a density of 1 per cm^3. Checking Wikipedia we can see that there are components of the interstellar medium with number densities between 10^6 and 10^-4.
It looks like the value in the presentation a rough ballpark estimate, but isn't off by more than a handful of orders of magnitude ;-)
How can such a vacuum coexist with the open system of earth’s atmosphere whereby debris from space can enter in?
While these two pressures can coexist in the same universe, they don't coexist in proximity at all. The interstellar medium is very, very far away from Earth's atmosphere, on the order of a lightyear.
Gravity keeps Earth's atmosphere nearby Earth, the solar system has gas produced by (and attracted by) the Sun's gravity. In interstellar space, there just isn't any source of gas, and what might have been there at one time has moved away, towards sources of gravity, over billions of years.
edited 15 mins ago
answered 1 hour ago
uhohuhoh
6,01221761
6,01221761
$begingroup$
Thank you for your response. Are you disputing the pressure on the moon also? Because if the pressure is out by a handful of magnitudes certainly between the moon and earth’s atmosphere there exist a vacuum of some sort at least as weak as a dyson vacuum cleaner. The notion that gravity holds the atmosphere in place but still is weak enough to allow gases to stratify depending on density or pressure is very difficult to wrap my head around. Not to mention that pressure requires something to press onto. What is the atmosphere pressing onto? The vacuum?
$endgroup$
– Autodidact
48 mins ago
$begingroup$
@Autodidact I have not disputed anything. I'm in general agreement with the powerpoint; within several orders of magnitude at least. The word "coexist" makes your question difficult to answer because you don't explain what you mean. They can coexist in the same universe, but not close to each other. I think a question about how the atmosphere ends up stratified in pressure due to gravity is a great one, but probably is better to ask in Earth Science SE or Physics SE.
$endgroup$
– uhoh
42 mins ago
1
$begingroup$
@Autodidact You may find several questions and answers like that in those sites already, best to read them before asking something that's been answered. Here is some related math, but there are probably better places to find a useful and head-wrappable explanation. en.wikipedia.org/wiki/Scale_height
$endgroup$
– uhoh
42 mins ago
1
$begingroup$
Thank you for the link. If this question is not asked in the correct stack, my sincerest apologies. Also my edit was not intended as a moving target, I didn’t want it dismissed. As for the atmosphere pressure, while the link provides a distance it doesn’t explain my inquiry, what is it pressing upon to generate the distance? That is a question to which I cannot seem to find an answer to. Gravity seems to be the answer but it’s powers are conflicting as I’ve pointed out. It’s sufficiently strong to resist a vacuum of 10^-11 but weak enough to let gas particles up 8.5 km up into the atmosphere.
$endgroup$
– Autodidact
23 mins ago
1
$begingroup$
The Moon kind of does have an atmosphere, but it's very thin, and its total mass is under 10 tonnes. See en.wikipedia.org/wiki/Atmosphere_of_the_Moon
$endgroup$
– PM 2Ring
16 mins ago
|
show 2 more comments
$begingroup$
Thank you for your response. Are you disputing the pressure on the moon also? Because if the pressure is out by a handful of magnitudes certainly between the moon and earth’s atmosphere there exist a vacuum of some sort at least as weak as a dyson vacuum cleaner. The notion that gravity holds the atmosphere in place but still is weak enough to allow gases to stratify depending on density or pressure is very difficult to wrap my head around. Not to mention that pressure requires something to press onto. What is the atmosphere pressing onto? The vacuum?
$endgroup$
– Autodidact
48 mins ago
$begingroup$
@Autodidact I have not disputed anything. I'm in general agreement with the powerpoint; within several orders of magnitude at least. The word "coexist" makes your question difficult to answer because you don't explain what you mean. They can coexist in the same universe, but not close to each other. I think a question about how the atmosphere ends up stratified in pressure due to gravity is a great one, but probably is better to ask in Earth Science SE or Physics SE.
$endgroup$
– uhoh
42 mins ago
1
$begingroup$
@Autodidact You may find several questions and answers like that in those sites already, best to read them before asking something that's been answered. Here is some related math, but there are probably better places to find a useful and head-wrappable explanation. en.wikipedia.org/wiki/Scale_height
$endgroup$
– uhoh
42 mins ago
1
$begingroup$
Thank you for the link. If this question is not asked in the correct stack, my sincerest apologies. Also my edit was not intended as a moving target, I didn’t want it dismissed. As for the atmosphere pressure, while the link provides a distance it doesn’t explain my inquiry, what is it pressing upon to generate the distance? That is a question to which I cannot seem to find an answer to. Gravity seems to be the answer but it’s powers are conflicting as I’ve pointed out. It’s sufficiently strong to resist a vacuum of 10^-11 but weak enough to let gas particles up 8.5 km up into the atmosphere.
$endgroup$
– Autodidact
23 mins ago
1
$begingroup$
The Moon kind of does have an atmosphere, but it's very thin, and its total mass is under 10 tonnes. See en.wikipedia.org/wiki/Atmosphere_of_the_Moon
$endgroup$
– PM 2Ring
16 mins ago
$begingroup$
Thank you for your response. Are you disputing the pressure on the moon also? Because if the pressure is out by a handful of magnitudes certainly between the moon and earth’s atmosphere there exist a vacuum of some sort at least as weak as a dyson vacuum cleaner. The notion that gravity holds the atmosphere in place but still is weak enough to allow gases to stratify depending on density or pressure is very difficult to wrap my head around. Not to mention that pressure requires something to press onto. What is the atmosphere pressing onto? The vacuum?
$endgroup$
– Autodidact
48 mins ago
$begingroup$
Thank you for your response. Are you disputing the pressure on the moon also? Because if the pressure is out by a handful of magnitudes certainly between the moon and earth’s atmosphere there exist a vacuum of some sort at least as weak as a dyson vacuum cleaner. The notion that gravity holds the atmosphere in place but still is weak enough to allow gases to stratify depending on density or pressure is very difficult to wrap my head around. Not to mention that pressure requires something to press onto. What is the atmosphere pressing onto? The vacuum?
$endgroup$
– Autodidact
48 mins ago
$begingroup$
@Autodidact I have not disputed anything. I'm in general agreement with the powerpoint; within several orders of magnitude at least. The word "coexist" makes your question difficult to answer because you don't explain what you mean. They can coexist in the same universe, but not close to each other. I think a question about how the atmosphere ends up stratified in pressure due to gravity is a great one, but probably is better to ask in Earth Science SE or Physics SE.
$endgroup$
– uhoh
42 mins ago
$begingroup$
@Autodidact I have not disputed anything. I'm in general agreement with the powerpoint; within several orders of magnitude at least. The word "coexist" makes your question difficult to answer because you don't explain what you mean. They can coexist in the same universe, but not close to each other. I think a question about how the atmosphere ends up stratified in pressure due to gravity is a great one, but probably is better to ask in Earth Science SE or Physics SE.
$endgroup$
– uhoh
42 mins ago
1
1
$begingroup$
@Autodidact You may find several questions and answers like that in those sites already, best to read them before asking something that's been answered. Here is some related math, but there are probably better places to find a useful and head-wrappable explanation. en.wikipedia.org/wiki/Scale_height
$endgroup$
– uhoh
42 mins ago
$begingroup$
@Autodidact You may find several questions and answers like that in those sites already, best to read them before asking something that's been answered. Here is some related math, but there are probably better places to find a useful and head-wrappable explanation. en.wikipedia.org/wiki/Scale_height
$endgroup$
– uhoh
42 mins ago
1
1
$begingroup$
Thank you for the link. If this question is not asked in the correct stack, my sincerest apologies. Also my edit was not intended as a moving target, I didn’t want it dismissed. As for the atmosphere pressure, while the link provides a distance it doesn’t explain my inquiry, what is it pressing upon to generate the distance? That is a question to which I cannot seem to find an answer to. Gravity seems to be the answer but it’s powers are conflicting as I’ve pointed out. It’s sufficiently strong to resist a vacuum of 10^-11 but weak enough to let gas particles up 8.5 km up into the atmosphere.
$endgroup$
– Autodidact
23 mins ago
$begingroup$
Thank you for the link. If this question is not asked in the correct stack, my sincerest apologies. Also my edit was not intended as a moving target, I didn’t want it dismissed. As for the atmosphere pressure, while the link provides a distance it doesn’t explain my inquiry, what is it pressing upon to generate the distance? That is a question to which I cannot seem to find an answer to. Gravity seems to be the answer but it’s powers are conflicting as I’ve pointed out. It’s sufficiently strong to resist a vacuum of 10^-11 but weak enough to let gas particles up 8.5 km up into the atmosphere.
$endgroup$
– Autodidact
23 mins ago
1
1
$begingroup$
The Moon kind of does have an atmosphere, but it's very thin, and its total mass is under 10 tonnes. See en.wikipedia.org/wiki/Atmosphere_of_the_Moon
$endgroup$
– PM 2Ring
16 mins ago
$begingroup$
The Moon kind of does have an atmosphere, but it's very thin, and its total mass is under 10 tonnes. See en.wikipedia.org/wiki/Atmosphere_of_the_Moon
$endgroup$
– PM 2Ring
16 mins ago
|
show 2 more comments
Autodidact is a new contributor. Be nice, and check out our Code of Conduct.
Autodidact is a new contributor. Be nice, and check out our Code of Conduct.
Autodidact is a new contributor. Be nice, and check out our Code of Conduct.
Autodidact is a new contributor. Be nice, and check out our Code of Conduct.
Thanks for contributing an answer to Astronomy Stack Exchange!
- Please be sure to answer the question. Provide details and share your research!
But avoid …
- Asking for help, clarification, or responding to other answers.
- Making statements based on opinion; back them up with references or personal experience.
Use MathJax to format equations. MathJax reference.
To learn more, see our tips on writing great answers.
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
StackExchange.ready(
function () {
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fastronomy.stackexchange.com%2fquestions%2f29832%2fvacuum-of-space-question%23new-answer', 'question_page');
}
);
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown