Using light as a barrier to block people without grilling them
$begingroup$
We know that light exerts pressure upon matter.
I'm imagining a hallway where an intense light source on one end shines towards the other end. The goal is to have the beam of light exert so much pressure that a human being cannot enter (or reach the end of) the hallway. Of course, we only want to deter the human, not to burn them to a crisp.
Would this be realistic?
science-based reality-check light radiation
edited 2 hours ago
Cyn
5,866935
asked 4 hours ago
user60406user60406
111
New contributor
user60406 is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
$endgroup$
add a comment |
$begingroup$
We know that light exerts pressure upon matter.
I'm imagining a hallway where an intense light source on one end shines towards the other end. The goal is to have the beam of light exert so much pressure that a human being cannot enter (or reach the end of) the hallway. Of course, we only want to deter the human, not to burn them to a crisp.
Would this be realistic?
science-based reality-check light radiation
edited 2 hours ago
Cyn
5,866935
asked 4 hours ago
user60406user60406
111
New contributor
user60406 is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
$endgroup$
1
$begingroup$
Naw, fam. I'm not sure what the math looks like (someone will draft that and put it into an answer, I'm sure), but that would definitely kill the person you are trying to repel.
$endgroup$
– user49466
3 hours ago
$begingroup$
Are you specifically looking at projecting light towards the person? Or are you also allowing things like projecting light upwards to create a barrier (e.g. laser wall) which still blocks passage but doesn't harm the person unless they try to cross?
$endgroup$
– Flater
2 mins ago
add a comment |
$begingroup$
We know that light exerts pressure upon matter.
I'm imagining a hallway where an intense light source on one end shines towards the other end. The goal is to have the beam of light exert so much pressure that a human being cannot enter (or reach the end of) the hallway. Of course, we only want to deter the human, not to burn them to a crisp.
Would this be realistic?
science-based reality-check light radiation
edited 2 hours ago
Cyn
5,866935
asked 4 hours ago
user60406user60406
111
New contributor
user60406 is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
$endgroup$
We know that light exerts pressure upon matter.
I'm imagining a hallway where an intense light source on one end shines towards the other end. The goal is to have the beam of light exert so much pressure that a human being cannot enter (or reach the end of) the hallway. Of course, we only want to deter the human, not to burn them to a crisp.
Would this be realistic?
science-based reality-check light radiation
science-based reality-check light radiation
edited 2 hours ago
Cyn
5,866935
asked 4 hours ago
user60406user60406
111
New contributor
user60406 is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
edited 2 hours ago
Cyn
5,866935
asked 4 hours ago
user60406user60406
111
New contributor
user60406 is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
edited 2 hours ago
Cyn
5,866935
edited 2 hours ago
Cyn
5,866935
edited 2 hours ago
Cyn
5,866935
5,866935
asked 4 hours ago
user60406user60406
111
New contributor
user60406 is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
asked 4 hours ago
user60406user60406
111
asked 4 hours ago
user60406user60406
111
111
New contributor
user60406 is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
New contributor
user60406 is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
user60406 is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
1
$begingroup$
Naw, fam. I'm not sure what the math looks like (someone will draft that and put it into an answer, I'm sure), but that would definitely kill the person you are trying to repel.
$endgroup$
– user49466
3 hours ago
$begingroup$
Are you specifically looking at projecting light towards the person? Or are you also allowing things like projecting light upwards to create a barrier (e.g. laser wall) which still blocks passage but doesn't harm the person unless they try to cross?
$endgroup$
– Flater
2 mins ago
add a comment |
1
$begingroup$
Naw, fam. I'm not sure what the math looks like (someone will draft that and put it into an answer, I'm sure), but that would definitely kill the person you are trying to repel.
$endgroup$
– user49466
3 hours ago
$begingroup$
Are you specifically looking at projecting light towards the person? Or are you also allowing things like projecting light upwards to create a barrier (e.g. laser wall) which still blocks passage but doesn't harm the person unless they try to cross?
$endgroup$
– Flater
2 mins ago
1
1
$begingroup$
Naw, fam. I'm not sure what the math looks like (someone will draft that and put it into an answer, I'm sure), but that would definitely kill the person you are trying to repel.
$endgroup$
– user49466
3 hours ago
$begingroup$
Naw, fam. I'm not sure what the math looks like (someone will draft that and put it into an answer, I'm sure), but that would definitely kill the person you are trying to repel.
$endgroup$
– user49466
3 hours ago
$begingroup$
Are you specifically looking at projecting light towards the person? Or are you also allowing things like projecting light upwards to create a barrier (e.g. laser wall) which still blocks passage but doesn't harm the person unless they try to cross?
$endgroup$
– Flater
2 mins ago
$begingroup$
Are you specifically looking at projecting light towards the person? Or are you also allowing things like projecting light upwards to create a barrier (e.g. laser wall) which still blocks passage but doesn't harm the person unless they try to cross?
$endgroup$
– Flater
2 mins ago
add a comment |
3 Answers
3
active
oldest
votes
$begingroup$
No, it won't be realistic.
The radiation pressure produced by an electromagnetic radiation of intensity, or better irradiance, $I_f$ impinging at an angle $alpha$ on a surface can be calculated according to
$P_{Inc}=$$I_f over c$$cdot cos^2 alpha$
where c is the speed of light.
You immediately see that, due to the c factor, you need huge irradiance to get meaningful pressures at human scale. Let's say you want to achieve $1 N/m^2$, you would need an irradiance of about $3 cdot 10^8 W/m^2$. That would char any human on which it impinges.
answered 3 hours ago
L.Dutch♦L.Dutch
79.4k26190387
$endgroup$
1
$begingroup$
Unless, of course, that human is very, very shiny. ;-)
$endgroup$
– Joe Bloggs
4 mins ago
1
$begingroup$
@JoeBloggs 1nationstyle.files.wordpress.com/2012/10/20121008-142556.jpg
$endgroup$
– Fabian Röling
1 min ago
add a comment |
$begingroup$
Not with light pressure. You need 300 megawatts of radiation flux for each Newton of force on the object (equivalent to the force exerted by a ~100 gram weight).
However, you can use microwaves as non-lethal deterrent. A moderate microwave flux is extremely painful on skin, well before it becomes damaging. This is the basis of several experimental crowd control weapons in real life, such as https://en.wikipedia.org/wiki/Active_Denial_System
answered 2 hours ago
tylisirntylisirn
31912
$endgroup$
add a comment |
$begingroup$
No
It's true that light exerts a pressure, but photons have no mass. You're dealing with pressure created by a distribution of energy, which is miniscule.
If you think about it, your skin burns on a beach — but you don't feel even the slightest pressure from the light that's burning you.
Now increase the light such that you could feel the pressure. You'd flash into a fine ash before you could comprehend that you were feeling pressure.
But!
What if you change your goal just a bit? What if the original intent of the light was to flash-burn anyone trying to get down the hall? Your protagonish knows this and dresses accordingly in attire that protects he/she from the burning properties of the light. And yet, as he/she walks down the hall, feels the pressure! pressure that's great enough to hinder progress! That would be a cool twist to the story.
answered 2 hours ago
JBHJBH
41k590195
$endgroup$
add a comment |
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: "579"
};
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
});
}
});
user60406 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%2fworldbuilding.stackexchange.com%2fquestions%2f136612%2fusing-light-as-a-barrier-to-block-people-without-grilling-them%23new-answer', 'question_page');
}
);
Post as a guest
Required, but never shown
3 Answers
3
active
oldest
votes
3 Answers
3
active
oldest
votes
active
oldest
votes
active
oldest
votes
$begingroup$
No, it won't be realistic.
The radiation pressure produced by an electromagnetic radiation of intensity, or better irradiance, $I_f$ impinging at an angle $alpha$ on a surface can be calculated according to
$P_{Inc}=$$I_f over c$$cdot cos^2 alpha$
where c is the speed of light.
You immediately see that, due to the c factor, you need huge irradiance to get meaningful pressures at human scale. Let's say you want to achieve $1 N/m^2$, you would need an irradiance of about $3 cdot 10^8 W/m^2$. That would char any human on which it impinges.
answered 3 hours ago
L.Dutch♦L.Dutch
79.4k26190387
$endgroup$
1
$begingroup$
Unless, of course, that human is very, very shiny. ;-)
$endgroup$
– Joe Bloggs
4 mins ago
1
$begingroup$
@JoeBloggs 1nationstyle.files.wordpress.com/2012/10/20121008-142556.jpg
$endgroup$
– Fabian Röling
1 min ago
add a comment |
$begingroup$
No, it won't be realistic.
The radiation pressure produced by an electromagnetic radiation of intensity, or better irradiance, $I_f$ impinging at an angle $alpha$ on a surface can be calculated according to
$P_{Inc}=$$I_f over c$$cdot cos^2 alpha$
where c is the speed of light.
You immediately see that, due to the c factor, you need huge irradiance to get meaningful pressures at human scale. Let's say you want to achieve $1 N/m^2$, you would need an irradiance of about $3 cdot 10^8 W/m^2$. That would char any human on which it impinges.
answered 3 hours ago
L.Dutch♦L.Dutch
79.4k26190387
$endgroup$
1
$begingroup$
Unless, of course, that human is very, very shiny. ;-)
$endgroup$
– Joe Bloggs
4 mins ago
1
$begingroup$
@JoeBloggs 1nationstyle.files.wordpress.com/2012/10/20121008-142556.jpg
$endgroup$
– Fabian Röling
1 min ago
add a comment |
$begingroup$
No, it won't be realistic.
The radiation pressure produced by an electromagnetic radiation of intensity, or better irradiance, $I_f$ impinging at an angle $alpha$ on a surface can be calculated according to
$P_{Inc}=$$I_f over c$$cdot cos^2 alpha$
where c is the speed of light.
You immediately see that, due to the c factor, you need huge irradiance to get meaningful pressures at human scale. Let's say you want to achieve $1 N/m^2$, you would need an irradiance of about $3 cdot 10^8 W/m^2$. That would char any human on which it impinges.
answered 3 hours ago
L.Dutch♦L.Dutch
79.4k26190387
$endgroup$
No, it won't be realistic.
The radiation pressure produced by an electromagnetic radiation of intensity, or better irradiance, $I_f$ impinging at an angle $alpha$ on a surface can be calculated according to
$P_{Inc}=$$I_f over c$$cdot cos^2 alpha$
where c is the speed of light.
You immediately see that, due to the c factor, you need huge irradiance to get meaningful pressures at human scale. Let's say you want to achieve $1 N/m^2$, you would need an irradiance of about $3 cdot 10^8 W/m^2$. That would char any human on which it impinges.
answered 3 hours ago
L.Dutch♦L.Dutch
79.4k26190387
answered 3 hours ago
L.Dutch♦L.Dutch
79.4k26190387
answered 3 hours ago
L.Dutch♦L.Dutch
79.4k26190387
answered 3 hours ago
L.Dutch♦L.Dutch
79.4k26190387
79.4k26190387
1
$begingroup$
Unless, of course, that human is very, very shiny. ;-)
$endgroup$
– Joe Bloggs
4 mins ago
1
$begingroup$
@JoeBloggs 1nationstyle.files.wordpress.com/2012/10/20121008-142556.jpg
$endgroup$
– Fabian Röling
1 min ago
add a comment |
1
$begingroup$
Unless, of course, that human is very, very shiny. ;-)
$endgroup$
– Joe Bloggs
4 mins ago
1
$begingroup$
@JoeBloggs 1nationstyle.files.wordpress.com/2012/10/20121008-142556.jpg
$endgroup$
– Fabian Röling
1 min ago
1
1
$begingroup$
Unless, of course, that human is very, very shiny. ;-)
$endgroup$
– Joe Bloggs
4 mins ago
$begingroup$
Unless, of course, that human is very, very shiny. ;-)
$endgroup$
– Joe Bloggs
4 mins ago
1
1
$begingroup$
@JoeBloggs 1nationstyle.files.wordpress.com/2012/10/20121008-142556.jpg
$endgroup$
– Fabian Röling
1 min ago
$begingroup$
@JoeBloggs 1nationstyle.files.wordpress.com/2012/10/20121008-142556.jpg
$endgroup$
– Fabian Röling
1 min ago
add a comment |
$begingroup$
Not with light pressure. You need 300 megawatts of radiation flux for each Newton of force on the object (equivalent to the force exerted by a ~100 gram weight).
However, you can use microwaves as non-lethal deterrent. A moderate microwave flux is extremely painful on skin, well before it becomes damaging. This is the basis of several experimental crowd control weapons in real life, such as https://en.wikipedia.org/wiki/Active_Denial_System
answered 2 hours ago
tylisirntylisirn
31912
$endgroup$
add a comment |
$begingroup$
Not with light pressure. You need 300 megawatts of radiation flux for each Newton of force on the object (equivalent to the force exerted by a ~100 gram weight).
However, you can use microwaves as non-lethal deterrent. A moderate microwave flux is extremely painful on skin, well before it becomes damaging. This is the basis of several experimental crowd control weapons in real life, such as https://en.wikipedia.org/wiki/Active_Denial_System
answered 2 hours ago
tylisirntylisirn
31912
$endgroup$
add a comment |
$begingroup$
Not with light pressure. You need 300 megawatts of radiation flux for each Newton of force on the object (equivalent to the force exerted by a ~100 gram weight).
However, you can use microwaves as non-lethal deterrent. A moderate microwave flux is extremely painful on skin, well before it becomes damaging. This is the basis of several experimental crowd control weapons in real life, such as https://en.wikipedia.org/wiki/Active_Denial_System
answered 2 hours ago
tylisirntylisirn
31912
$endgroup$
Not with light pressure. You need 300 megawatts of radiation flux for each Newton of force on the object (equivalent to the force exerted by a ~100 gram weight).
However, you can use microwaves as non-lethal deterrent. A moderate microwave flux is extremely painful on skin, well before it becomes damaging. This is the basis of several experimental crowd control weapons in real life, such as https://en.wikipedia.org/wiki/Active_Denial_System
answered 2 hours ago
tylisirntylisirn
31912
answered 2 hours ago
tylisirntylisirn
31912
answered 2 hours ago
tylisirntylisirn
31912
answered 2 hours ago
tylisirntylisirn
31912
31912
add a comment |
add a comment |
$begingroup$
No
It's true that light exerts a pressure, but photons have no mass. You're dealing with pressure created by a distribution of energy, which is miniscule.
If you think about it, your skin burns on a beach — but you don't feel even the slightest pressure from the light that's burning you.
Now increase the light such that you could feel the pressure. You'd flash into a fine ash before you could comprehend that you were feeling pressure.
But!
What if you change your goal just a bit? What if the original intent of the light was to flash-burn anyone trying to get down the hall? Your protagonish knows this and dresses accordingly in attire that protects he/she from the burning properties of the light. And yet, as he/she walks down the hall, feels the pressure! pressure that's great enough to hinder progress! That would be a cool twist to the story.
answered 2 hours ago
JBHJBH
41k590195
$endgroup$
add a comment |
$begingroup$
No
It's true that light exerts a pressure, but photons have no mass. You're dealing with pressure created by a distribution of energy, which is miniscule.
If you think about it, your skin burns on a beach — but you don't feel even the slightest pressure from the light that's burning you.
Now increase the light such that you could feel the pressure. You'd flash into a fine ash before you could comprehend that you were feeling pressure.
But!
What if you change your goal just a bit? What if the original intent of the light was to flash-burn anyone trying to get down the hall? Your protagonish knows this and dresses accordingly in attire that protects he/she from the burning properties of the light. And yet, as he/she walks down the hall, feels the pressure! pressure that's great enough to hinder progress! That would be a cool twist to the story.
answered 2 hours ago
JBHJBH
41k590195
$endgroup$
add a comment |
$begingroup$
No
It's true that light exerts a pressure, but photons have no mass. You're dealing with pressure created by a distribution of energy, which is miniscule.
If you think about it, your skin burns on a beach — but you don't feel even the slightest pressure from the light that's burning you.
Now increase the light such that you could feel the pressure. You'd flash into a fine ash before you could comprehend that you were feeling pressure.
But!
What if you change your goal just a bit? What if the original intent of the light was to flash-burn anyone trying to get down the hall? Your protagonish knows this and dresses accordingly in attire that protects he/she from the burning properties of the light. And yet, as he/she walks down the hall, feels the pressure! pressure that's great enough to hinder progress! That would be a cool twist to the story.
answered 2 hours ago
JBHJBH
41k590195
$endgroup$
No
It's true that light exerts a pressure, but photons have no mass. You're dealing with pressure created by a distribution of energy, which is miniscule.
If you think about it, your skin burns on a beach — but you don't feel even the slightest pressure from the light that's burning you.
Now increase the light such that you could feel the pressure. You'd flash into a fine ash before you could comprehend that you were feeling pressure.
But!
What if you change your goal just a bit? What if the original intent of the light was to flash-burn anyone trying to get down the hall? Your protagonish knows this and dresses accordingly in attire that protects he/she from the burning properties of the light. And yet, as he/she walks down the hall, feels the pressure! pressure that's great enough to hinder progress! That would be a cool twist to the story.
answered 2 hours ago
JBHJBH
41k590195
answered 2 hours ago
JBHJBH
41k590195
answered 2 hours ago
JBHJBH
41k590195
answered 2 hours ago
JBHJBH
41k590195
41k590195
add a comment |
add a comment |
user60406 is a new contributor. Be nice, and check out our Code of Conduct.
user60406 is a new contributor. Be nice, and check out our Code of Conduct.
user60406 is a new contributor. Be nice, and check out our Code of Conduct.
user60406 is a new contributor. Be nice, and check out our Code of Conduct.
Thanks for contributing an answer to Worldbuilding 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%2fworldbuilding.stackexchange.com%2fquestions%2f136612%2fusing-light-as-a-barrier-to-block-people-without-grilling-them%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
1
$begingroup$
Naw, fam. I'm not sure what the math looks like (someone will draft that and put it into an answer, I'm sure), but that would definitely kill the person you are trying to repel.
$endgroup$
– user49466
3 hours ago
$begingroup$
Are you specifically looking at projecting light towards the person? Or are you also allowing things like projecting light upwards to create a barrier (e.g. laser wall) which still blocks passage but doesn't harm the person unless they try to cross?
$endgroup$
– Flater
2 mins ago