Where is the intervening light in the M87 black hole? Announcing the arrival of Valued Associate #679: Cesar Manara Planned maintenance scheduled April 17/18, 2019 at 00:00UTC (8:00pm US/Eastern) What stellar content do we want to share with Twitter?Statistically, what would the average distance of the closest black hole be?How can black holes be sometimes so gaseous?How did the object CO-0.40-0.22 get its name, and how is it distinct from CO-0.40-0.22*?What will happen to the shape of a galaxy when a super massive black hole lying in its center dies(evaporates out)?How did the authors determine both the spatial size of gas cloud HCN-0.009-0.044 and its central mass at the same time?Why does the author believe that the central mass that gas cloud HCN-0.009-0.044 orbits is smaller than our solar system?Is this the best non-radio image of whatever's at the center of M87? How was it taken?Why isn't the relativistic jet visible in the image of the M87 black hole?Why is the ring of light around the M87 black hole bigger than the photon sphere?Is there any estimate of the size of the M87 black hole?
What items from the Roman-age tech-level could be used to deter all creatures from entering a small area?
How can I protect witches in combat who wear limited clothing?
Am I ethically obligated to go into work on an off day if the reason is sudden?
How does modal jazz use chord progressions?
Can a 1st-level character have an ability score above 18?
Is it possible to ask for a hotel room without minibar/extra services?
Does a C shift expression have unsigned type? Why would Splint warn about a right-shift?
How to politely respond to generic emails requesting a PhD/job in my lab? Without wasting too much time
Array/tabular for long multiplication
Do working physicists consider Newtonian mechanics to be "falsified"?
Determine whether f is a function, an injection, a surjection
How to add zeros to reach same number of decimal places in tables?
How many spell slots should a Fighter 11/Ranger 9 have?
Why does this iterative way of solving of equation work?
Using "nakedly" instead of "with nothing on"
Aligning matrix of nodes with grid
What kind of display is this?
Mortgage adviser recommends a longer term than necessary combined with overpayments
Single author papers against my advisor's will?
Would an alien lifeform be able to achieve space travel if lacking in vision?
Can the prologue be the backstory of your main character?
Windows 10: How to Lock (not sleep) laptop on lid close?
Slither Like a Snake
What would be Julian Assange's expected punishment, on the current English criminal law?
Where is the intervening light in the M87 black hole?
Announcing the arrival of Valued Associate #679: Cesar Manara
Planned maintenance scheduled April 17/18, 2019 at 00:00UTC (8:00pm US/Eastern)
What stellar content do we want to share with Twitter?Statistically, what would the average distance of the closest black hole be?How can black holes be sometimes so gaseous?How did the object CO-0.40-0.22 get its name, and how is it distinct from CO-0.40-0.22*?What will happen to the shape of a galaxy when a super massive black hole lying in its center dies(evaporates out)?How did the authors determine both the spatial size of gas cloud HCN-0.009-0.044 and its central mass at the same time?Why does the author believe that the central mass that gas cloud HCN-0.009-0.044 orbits is smaller than our solar system?Is this the best non-radio image of whatever's at the center of M87? How was it taken?Why isn't the relativistic jet visible in the image of the M87 black hole?Why is the ring of light around the M87 black hole bigger than the photon sphere?Is there any estimate of the size of the M87 black hole?
$begingroup$
The M87 black hole is at the centre, more or less, of an elliptical galaxy of 1 trillion or more stars. So certainly there are stars and other light emitting objects (emission nebula e.g.) in the intervening 53 million light years between earth and the black hole.
How is it that the centre of the black hole image is perfectly dark, as if it is being observed directly, with not one point of light between the black hole and earth? I appreciate that space is mostly empty, but do we really have an unobscured line of sight to a black hole in the centre of an enormous elliptical galaxy?
Does it have something to do with the type of light being observed?
black-hole m87
edited 56 mins ago
Peter Mortensen
1556
asked 10 hours ago
Bumptious Q BangwhistleBumptious Q Bangwhistle
1715
New contributor
Bumptious Q Bangwhistle 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 |
$begingroup$
The M87 black hole is at the centre, more or less, of an elliptical galaxy of 1 trillion or more stars. So certainly there are stars and other light emitting objects (emission nebula e.g.) in the intervening 53 million light years between earth and the black hole.
How is it that the centre of the black hole image is perfectly dark, as if it is being observed directly, with not one point of light between the black hole and earth? I appreciate that space is mostly empty, but do we really have an unobscured line of sight to a black hole in the centre of an enormous elliptical galaxy?
Does it have something to do with the type of light being observed?
black-hole m87
edited 56 mins ago
Peter Mortensen
1556
asked 10 hours ago
Bumptious Q BangwhistleBumptious Q Bangwhistle
1715
New contributor
Bumptious Q Bangwhistle is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
$endgroup$
$begingroup$
I think it's mostly that the field of view is incredibly tiny. The popular published image seems to be about four times the diameter of the central dark region, so representing about 800 billion km at the distance of M87 or about 0.1 light year. At the distance of the edge of our galaxy, it would represent about 1/1000 of that. There simply isn't anything in that very very narrow cone bright enough to show up.
$endgroup$
– Steve Linton
10 hours ago
1
$begingroup$
Also, the observations are made in radio, where intervening gas and dust hardly absorbs anything.
$endgroup$
– pela
10 hours ago
add a comment |
$begingroup$
The M87 black hole is at the centre, more or less, of an elliptical galaxy of 1 trillion or more stars. So certainly there are stars and other light emitting objects (emission nebula e.g.) in the intervening 53 million light years between earth and the black hole.
How is it that the centre of the black hole image is perfectly dark, as if it is being observed directly, with not one point of light between the black hole and earth? I appreciate that space is mostly empty, but do we really have an unobscured line of sight to a black hole in the centre of an enormous elliptical galaxy?
Does it have something to do with the type of light being observed?
black-hole m87
edited 56 mins ago
Peter Mortensen
1556
asked 10 hours ago
Bumptious Q BangwhistleBumptious Q Bangwhistle
1715
New contributor
Bumptious Q Bangwhistle is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
$endgroup$
The M87 black hole is at the centre, more or less, of an elliptical galaxy of 1 trillion or more stars. So certainly there are stars and other light emitting objects (emission nebula e.g.) in the intervening 53 million light years between earth and the black hole.
How is it that the centre of the black hole image is perfectly dark, as if it is being observed directly, with not one point of light between the black hole and earth? I appreciate that space is mostly empty, but do we really have an unobscured line of sight to a black hole in the centre of an enormous elliptical galaxy?
Does it have something to do with the type of light being observed?
black-hole m87
black-hole m87
edited 56 mins ago
Peter Mortensen
1556
asked 10 hours ago
Bumptious Q BangwhistleBumptious Q Bangwhistle
1715
New contributor
Bumptious Q Bangwhistle is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
edited 56 mins ago
Peter Mortensen
1556
asked 10 hours ago
Bumptious Q BangwhistleBumptious Q Bangwhistle
1715
New contributor
Bumptious Q Bangwhistle is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
edited 56 mins ago
Peter Mortensen
1556
edited 56 mins ago
Peter Mortensen
1556
edited 56 mins ago
Peter Mortensen
1556
1556
asked 10 hours ago
Bumptious Q BangwhistleBumptious Q Bangwhistle
1715
New contributor
Bumptious Q Bangwhistle is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
asked 10 hours ago
Bumptious Q BangwhistleBumptious Q Bangwhistle
1715
asked 10 hours ago
Bumptious Q BangwhistleBumptious Q Bangwhistle
1715
1715
New contributor
Bumptious Q Bangwhistle is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
New contributor
Bumptious Q Bangwhistle is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
Bumptious Q Bangwhistle is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
$begingroup$
I think it's mostly that the field of view is incredibly tiny. The popular published image seems to be about four times the diameter of the central dark region, so representing about 800 billion km at the distance of M87 or about 0.1 light year. At the distance of the edge of our galaxy, it would represent about 1/1000 of that. There simply isn't anything in that very very narrow cone bright enough to show up.
$endgroup$
– Steve Linton
10 hours ago
1
$begingroup$
Also, the observations are made in radio, where intervening gas and dust hardly absorbs anything.
$endgroup$
– pela
10 hours ago
add a comment |
$begingroup$
I think it's mostly that the field of view is incredibly tiny. The popular published image seems to be about four times the diameter of the central dark region, so representing about 800 billion km at the distance of M87 or about 0.1 light year. At the distance of the edge of our galaxy, it would represent about 1/1000 of that. There simply isn't anything in that very very narrow cone bright enough to show up.
$endgroup$
– Steve Linton
10 hours ago
1
$begingroup$
Also, the observations are made in radio, where intervening gas and dust hardly absorbs anything.
$endgroup$
– pela
10 hours ago
$begingroup$
I think it's mostly that the field of view is incredibly tiny. The popular published image seems to be about four times the diameter of the central dark region, so representing about 800 billion km at the distance of M87 or about 0.1 light year. At the distance of the edge of our galaxy, it would represent about 1/1000 of that. There simply isn't anything in that very very narrow cone bright enough to show up.
$endgroup$
– Steve Linton
10 hours ago
$begingroup$
I think it's mostly that the field of view is incredibly tiny. The popular published image seems to be about four times the diameter of the central dark region, so representing about 800 billion km at the distance of M87 or about 0.1 light year. At the distance of the edge of our galaxy, it would represent about 1/1000 of that. There simply isn't anything in that very very narrow cone bright enough to show up.
$endgroup$
– Steve Linton
10 hours ago
1
1
$begingroup$
Also, the observations are made in radio, where intervening gas and dust hardly absorbs anything.
$endgroup$
– pela
10 hours ago
$begingroup$
Also, the observations are made in radio, where intervening gas and dust hardly absorbs anything.
$endgroup$
– pela
10 hours ago
add a comment |
1 Answer
1
active
oldest
votes
$begingroup$
Based on the comment from @SteveLinton
The radius of M87 is given to be 60,000 light years, which is a volume of 900 trillion cubic light years. Given that it contains roughly one trillion stars, there is an average of 900 cubic light years for each star.
Several resources referred to the diameter of the black hole in the range of 1.5 light days (38 billion km). That's 0.004 light years.
If you consider the cylinder1 extending from the black hole to the edge of M87, the cylinder is 0.004 light years in diameter with a height of 60,000 light years. The volume of that cylinder is just over 3 cubic light years. Since there is one star for every 900 cubic light years, it follows that the cylinder encompassing our line of sight between the black hole and the edge of M87 is empty of any stars.
Whether or not any star would even be bright enough to be visible is another matter.
1Technically a conic frustum but I don't think the difference in volume is significant.
answered 9 hours ago
Bumptious Q BangwhistleBumptious Q Bangwhistle
1715
New contributor
Bumptious Q Bangwhistle is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
$endgroup$
$begingroup$
"The radius of M87 is given to be 60,000 light years.". No, more like 32 - 50 kiloparsecs radius = 100,000 - 160,000 light years radius. E.g. "According to Stoyan et al. (2010), the distance of M87 is 54.9 million light years and its diameter is 132,000 light years." and "Diameter: 120,000 ly".
$endgroup$
– Peter Mortensen
1 hour ago
$begingroup$
Doesn't this answer assume that the galaxy is of uniform density?
$endgroup$
– JBentley
1 hour ago
add a comment |
Your Answer
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
);
);
Bumptious Q Bangwhistle 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%2f30444%2fwhere-is-the-intervening-light-in-the-m87-black-hole%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
$begingroup$
Based on the comment from @SteveLinton
The radius of M87 is given to be 60,000 light years, which is a volume of 900 trillion cubic light years. Given that it contains roughly one trillion stars, there is an average of 900 cubic light years for each star.
Several resources referred to the diameter of the black hole in the range of 1.5 light days (38 billion km). That's 0.004 light years.
If you consider the cylinder1 extending from the black hole to the edge of M87, the cylinder is 0.004 light years in diameter with a height of 60,000 light years. The volume of that cylinder is just over 3 cubic light years. Since there is one star for every 900 cubic light years, it follows that the cylinder encompassing our line of sight between the black hole and the edge of M87 is empty of any stars.
Whether or not any star would even be bright enough to be visible is another matter.
1Technically a conic frustum but I don't think the difference in volume is significant.
answered 9 hours ago
Bumptious Q BangwhistleBumptious Q Bangwhistle
1715
New contributor
Bumptious Q Bangwhistle is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
$endgroup$
$begingroup$
"The radius of M87 is given to be 60,000 light years.". No, more like 32 - 50 kiloparsecs radius = 100,000 - 160,000 light years radius. E.g. "According to Stoyan et al. (2010), the distance of M87 is 54.9 million light years and its diameter is 132,000 light years." and "Diameter: 120,000 ly".
$endgroup$
– Peter Mortensen
1 hour ago
$begingroup$
Doesn't this answer assume that the galaxy is of uniform density?
$endgroup$
– JBentley
1 hour ago
add a comment |
$begingroup$
Based on the comment from @SteveLinton
The radius of M87 is given to be 60,000 light years, which is a volume of 900 trillion cubic light years. Given that it contains roughly one trillion stars, there is an average of 900 cubic light years for each star.
Several resources referred to the diameter of the black hole in the range of 1.5 light days (38 billion km). That's 0.004 light years.
If you consider the cylinder1 extending from the black hole to the edge of M87, the cylinder is 0.004 light years in diameter with a height of 60,000 light years. The volume of that cylinder is just over 3 cubic light years. Since there is one star for every 900 cubic light years, it follows that the cylinder encompassing our line of sight between the black hole and the edge of M87 is empty of any stars.
Whether or not any star would even be bright enough to be visible is another matter.
1Technically a conic frustum but I don't think the difference in volume is significant.
answered 9 hours ago
Bumptious Q BangwhistleBumptious Q Bangwhistle
1715
New contributor
Bumptious Q Bangwhistle is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
$endgroup$
$begingroup$
"The radius of M87 is given to be 60,000 light years.". No, more like 32 - 50 kiloparsecs radius = 100,000 - 160,000 light years radius. E.g. "According to Stoyan et al. (2010), the distance of M87 is 54.9 million light years and its diameter is 132,000 light years." and "Diameter: 120,000 ly".
$endgroup$
– Peter Mortensen
1 hour ago
$begingroup$
Doesn't this answer assume that the galaxy is of uniform density?
$endgroup$
– JBentley
1 hour ago
add a comment |
$begingroup$
Based on the comment from @SteveLinton
The radius of M87 is given to be 60,000 light years, which is a volume of 900 trillion cubic light years. Given that it contains roughly one trillion stars, there is an average of 900 cubic light years for each star.
Several resources referred to the diameter of the black hole in the range of 1.5 light days (38 billion km). That's 0.004 light years.
If you consider the cylinder1 extending from the black hole to the edge of M87, the cylinder is 0.004 light years in diameter with a height of 60,000 light years. The volume of that cylinder is just over 3 cubic light years. Since there is one star for every 900 cubic light years, it follows that the cylinder encompassing our line of sight between the black hole and the edge of M87 is empty of any stars.
Whether or not any star would even be bright enough to be visible is another matter.
1Technically a conic frustum but I don't think the difference in volume is significant.
answered 9 hours ago
Bumptious Q BangwhistleBumptious Q Bangwhistle
1715
New contributor
Bumptious Q Bangwhistle is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
$endgroup$
Based on the comment from @SteveLinton
The radius of M87 is given to be 60,000 light years, which is a volume of 900 trillion cubic light years. Given that it contains roughly one trillion stars, there is an average of 900 cubic light years for each star.
Several resources referred to the diameter of the black hole in the range of 1.5 light days (38 billion km). That's 0.004 light years.
If you consider the cylinder1 extending from the black hole to the edge of M87, the cylinder is 0.004 light years in diameter with a height of 60,000 light years. The volume of that cylinder is just over 3 cubic light years. Since there is one star for every 900 cubic light years, it follows that the cylinder encompassing our line of sight between the black hole and the edge of M87 is empty of any stars.
Whether or not any star would even be bright enough to be visible is another matter.
1Technically a conic frustum but I don't think the difference in volume is significant.
answered 9 hours ago
Bumptious Q BangwhistleBumptious Q Bangwhistle
1715
New contributor
Bumptious Q Bangwhistle is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
edited 9 hours ago
answered 9 hours ago
Bumptious Q BangwhistleBumptious Q Bangwhistle
1715
New contributor
Bumptious Q Bangwhistle is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
answered 9 hours ago
Bumptious Q BangwhistleBumptious Q Bangwhistle
1715
answered 9 hours ago
Bumptious Q BangwhistleBumptious Q Bangwhistle
1715
1715
New contributor
Bumptious Q Bangwhistle is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
New contributor
Bumptious Q Bangwhistle is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
Bumptious Q Bangwhistle is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
$begingroup$
"The radius of M87 is given to be 60,000 light years.". No, more like 32 - 50 kiloparsecs radius = 100,000 - 160,000 light years radius. E.g. "According to Stoyan et al. (2010), the distance of M87 is 54.9 million light years and its diameter is 132,000 light years." and "Diameter: 120,000 ly".
$endgroup$
– Peter Mortensen
1 hour ago
$begingroup$
Doesn't this answer assume that the galaxy is of uniform density?
$endgroup$
– JBentley
1 hour ago
add a comment |
$begingroup$
"The radius of M87 is given to be 60,000 light years.". No, more like 32 - 50 kiloparsecs radius = 100,000 - 160,000 light years radius. E.g. "According to Stoyan et al. (2010), the distance of M87 is 54.9 million light years and its diameter is 132,000 light years." and "Diameter: 120,000 ly".
$endgroup$
– Peter Mortensen
1 hour ago
$begingroup$
Doesn't this answer assume that the galaxy is of uniform density?
$endgroup$
– JBentley
1 hour ago
$begingroup$
"The radius of M87 is given to be 60,000 light years.". No, more like 32 - 50 kiloparsecs radius = 100,000 - 160,000 light years radius. E.g. "According to Stoyan et al. (2010), the distance of M87 is 54.9 million light years and its diameter is 132,000 light years." and "Diameter: 120,000 ly".
$endgroup$
– Peter Mortensen
1 hour ago
$begingroup$
"The radius of M87 is given to be 60,000 light years.". No, more like 32 - 50 kiloparsecs radius = 100,000 - 160,000 light years radius. E.g. "According to Stoyan et al. (2010), the distance of M87 is 54.9 million light years and its diameter is 132,000 light years." and "Diameter: 120,000 ly".
$endgroup$
– Peter Mortensen
1 hour ago
$begingroup$
Doesn't this answer assume that the galaxy is of uniform density?
$endgroup$
– JBentley
1 hour ago
$begingroup$
Doesn't this answer assume that the galaxy is of uniform density?
$endgroup$
– JBentley
1 hour ago
add a comment |
Bumptious Q Bangwhistle is a new contributor. Be nice, and check out our Code of Conduct.
Bumptious Q Bangwhistle is a new contributor. Be nice, and check out our Code of Conduct.
Bumptious Q Bangwhistle is a new contributor. Be nice, and check out our Code of Conduct.
Bumptious Q Bangwhistle 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%2f30444%2fwhere-is-the-intervening-light-in-the-m87-black-hole%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
$begingroup$
I think it's mostly that the field of view is incredibly tiny. The popular published image seems to be about four times the diameter of the central dark region, so representing about 800 billion km at the distance of M87 or about 0.1 light year. At the distance of the edge of our galaxy, it would represent about 1/1000 of that. There simply isn't anything in that very very narrow cone bright enough to show up.
$endgroup$
– Steve Linton
10 hours ago
1
$begingroup$
Also, the observations are made in radio, where intervening gas and dust hardly absorbs anything.
$endgroup$
– pela
10 hours ago