Can anything be seen from the center of the Boötes void? How dark would it be?
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Let's say I was at the very center of the enormous Boötes void, way out in deep, deep space. What could I see with the naked eye? I assume I could see no individual stars, but could I resolve any galaxies? If I gazed in the direction of a super-cluster of galaxies would it seem brighter than other directions? How dark would it be compared to, say, the far side of the moon when it is a full moon on earth?
I am told there are, in fact, a few galaxies in the void. So let's say I pick a spot in the void that is as far from any of those galaxies as possible.
astronomy
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add a comment |
$begingroup$
Let's say I was at the very center of the enormous Boötes void, way out in deep, deep space. What could I see with the naked eye? I assume I could see no individual stars, but could I resolve any galaxies? If I gazed in the direction of a super-cluster of galaxies would it seem brighter than other directions? How dark would it be compared to, say, the far side of the moon when it is a full moon on earth?
I am told there are, in fact, a few galaxies in the void. So let's say I pick a spot in the void that is as far from any of those galaxies as possible.
astronomy
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The Bootes void has some galaxies in it, and I don't know if it has much of a centre. IMO this needs to be more specific about the conditions.
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– JMac
yesterday
5
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Let's pick the spot that is furthest from any galaxy.
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– Paul Young
yesterday
10
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@PaulYoung so you're saying "if there's a bright center to the Universe, you're at the [point] it's farthest from"?
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– MikeTheLiar
yesterday
2
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@MikeTheLiar seems more like "let's get as far away from as many galaxies as possible"
$endgroup$
– immibis
yesterday
add a comment |
$begingroup$
Let's say I was at the very center of the enormous Boötes void, way out in deep, deep space. What could I see with the naked eye? I assume I could see no individual stars, but could I resolve any galaxies? If I gazed in the direction of a super-cluster of galaxies would it seem brighter than other directions? How dark would it be compared to, say, the far side of the moon when it is a full moon on earth?
I am told there are, in fact, a few galaxies in the void. So let's say I pick a spot in the void that is as far from any of those galaxies as possible.
astronomy
$endgroup$
Let's say I was at the very center of the enormous Boötes void, way out in deep, deep space. What could I see with the naked eye? I assume I could see no individual stars, but could I resolve any galaxies? If I gazed in the direction of a super-cluster of galaxies would it seem brighter than other directions? How dark would it be compared to, say, the far side of the moon when it is a full moon on earth?
I am told there are, in fact, a few galaxies in the void. So let's say I pick a spot in the void that is as far from any of those galaxies as possible.
astronomy
astronomy
edited yesterday
costrom
314128
314128
asked yesterday
Paul YoungPaul Young
1,386317
1,386317
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The Bootes void has some galaxies in it, and I don't know if it has much of a centre. IMO this needs to be more specific about the conditions.
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– JMac
yesterday
5
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Let's pick the spot that is furthest from any galaxy.
$endgroup$
– Paul Young
yesterday
10
$begingroup$
@PaulYoung so you're saying "if there's a bright center to the Universe, you're at the [point] it's farthest from"?
$endgroup$
– MikeTheLiar
yesterday
2
$begingroup$
@MikeTheLiar seems more like "let's get as far away from as many galaxies as possible"
$endgroup$
– immibis
yesterday
add a comment |
$begingroup$
The Bootes void has some galaxies in it, and I don't know if it has much of a centre. IMO this needs to be more specific about the conditions.
$endgroup$
– JMac
yesterday
5
$begingroup$
Let's pick the spot that is furthest from any galaxy.
$endgroup$
– Paul Young
yesterday
10
$begingroup$
@PaulYoung so you're saying "if there's a bright center to the Universe, you're at the [point] it's farthest from"?
$endgroup$
– MikeTheLiar
yesterday
2
$begingroup$
@MikeTheLiar seems more like "let's get as far away from as many galaxies as possible"
$endgroup$
– immibis
yesterday
$begingroup$
The Bootes void has some galaxies in it, and I don't know if it has much of a centre. IMO this needs to be more specific about the conditions.
$endgroup$
– JMac
yesterday
$begingroup$
The Bootes void has some galaxies in it, and I don't know if it has much of a centre. IMO this needs to be more specific about the conditions.
$endgroup$
– JMac
yesterday
5
5
$begingroup$
Let's pick the spot that is furthest from any galaxy.
$endgroup$
– Paul Young
yesterday
$begingroup$
Let's pick the spot that is furthest from any galaxy.
$endgroup$
– Paul Young
yesterday
10
10
$begingroup$
@PaulYoung so you're saying "if there's a bright center to the Universe, you're at the [point] it's farthest from"?
$endgroup$
– MikeTheLiar
yesterday
$begingroup$
@PaulYoung so you're saying "if there's a bright center to the Universe, you're at the [point] it's farthest from"?
$endgroup$
– MikeTheLiar
yesterday
2
2
$begingroup$
@MikeTheLiar seems more like "let's get as far away from as many galaxies as possible"
$endgroup$
– immibis
yesterday
$begingroup$
@MikeTheLiar seems more like "let's get as far away from as many galaxies as possible"
$endgroup$
– immibis
yesterday
add a comment |
3 Answers
3
active
oldest
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The number density of galaxies in a void is typically an order of magnitude lower than the average in the Universe (e.g. Patiri et al. 2006). In this astronomy.SE post, I estimate the number density of galaxies of magnitude $M=-17$ or brighter in the Boötes Void to be $n sim 0.004,mathrm{Mpc}^{-3}$, or $10^{-4},mathrm{Mlyr}^{-3}$ (i.e. "per cubic mega-light-year"). Hence, the typical distance to a galaxy from a random point in the Boötes Void is
$$
d = left( frac{3}{4pi n} right)^{1/3} simeq 13,mathrm{Mlyr}.
$$
That distance corresponds to a distance modulus of $mu simeq 28$, so the apparent magnitude of the galaxy would be
$$
m = M + mu simeq 11.
$$
Typically, humans cannot see objects darker than $m simeq 6.5$ (the magnitude scale is backwards, so darker means "larger values than 6.5"), although some have claimed to be able to see $msimeq8$ — still an order of magnitude brighter than the $m=11$ estimated above. Moreover, this threshold assumes point sources, whereas a galaxy has its brightness smeared out over a quite large area, lowering its surface brightness significantly!$^dagger$. Note also that, as in the rest of the Universe, galaxies in voids are not completely randomly scattered throughout space, but tend to cluster in clumps and filaments, and that the number density is smaller in the center of the void, meaning that here the typical distance to the next galaxy is larger.
Hence, you would be floating in complete darkness.$^ddagger$
$^dagger$For instance, the Andromeda galaxy has an apparent magnitude of $m=3.44$ which, if its light were concentrated in a point, would make it easily visibly even under light-polluted conditions.
$^ddagger$Your eye might be able to detect individual photons, at stated in Árpád Szendrei's answer, but that hardly counts as "seeing anything".
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14
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Well, that's an utterly terrifying concept to imagine. Thanks to everyone for making me aware of it, I am going to go lie down now
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– llama
yesterday
7
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@llama Luckily, the terrifying scenario would be over in a minute, after which you'd die from asphyxia.
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– pela
yesterday
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Maybe Hal would open the pod bay doors
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– Paul Young
yesterday
3
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Fascinating. I had no idea that such a place would exist. The Wikipedia article that's now linked from the question backs up your calculations, saying that if the Milky Way were at the centre of the Boötes Void, we wouldn't have known that there were other galaxies until the 1960s.
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– David Richerby
12 hours ago
1
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@binaryfunt Indeed, though I think it may have been a void between stars in our own galaxy i.e. between the spiral arms, rather than between galaxies.
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– Martin Carney
4 hours ago
|
show 3 more comments
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From the Wikipedia page on the Boötes void (the same that you linked to in your question):
According to astronomer Greg Aldering, the scale of the void is such that "If the Milky Way had been in the center of the Boötes void, we wouldn't have known there were other galaxies until the 1960s."
(The original article can be found thanks to the Wayback Machine.)
This means that if we were in the center of the Boötes void, we wouldn't be able to see any galaxies with the naked eye, and not even with some telescopes. Again according to Wikipedia, telescopes were invented at the beginning of the 17th century, radio telescopes in the 1930s and infrared telescopes in the 1960s.
New contributor
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1
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That quote and that I share Llama’s reaction to pela’s answer are what inspired the question.
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– Paul Young
yesterday
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Note that the Wikipedia page wasn't linked in the original version of the question -- that was added by somebody else, later.
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– David Richerby
12 hours ago
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hence the OP's upvote to Fabio ...
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– Paul Young
8 hours ago
add a comment |
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In fact you would see only individual stars. Like on Earth, you can only see individual stars, and no galaxies with the naked eye. Why? Because galaxies are too dim as a whole.
Now, if you would just float in empty space in the void you would be better off then on Earth. It is because here on Earth there is some light pollution.
But in the void, there is basically no light pollution, so you could see even single photons arriving from far away giant stars.
And yes, the human eye is able to detect even single photons.
By the way, all the stars that you can see with the naked eye from Earth are from the Milky Way. But again, that is too because of the light pollution and because our night sky even if there would be no light pollution here on Earth would be filled with brighter start from the Milky way. Our eyes would get used to that, and the start from other galaxies would just appear too dim to see.
Now on the dark side of the moon it would be a little different, but only that there is no light pollution like on Earth. Still, from the dark side of the Moon you could still only see stars from the Milky way.
Now in the void in your case, I think it is different. It is so dark and void, that even a single photon coming from a far away large star would be visible to our eyes that get used to the darkness.
Please see here:
Do all the individual stars that we can see in the night sky belong to Milky Way?
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9
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You can see Andromeda with the naked eye, under optimal conditions. It's mag +3.44. Sagittarius Dwarf Spheroidal Galaxy and M33 should also be visible
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– CSM
yesterday
7
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the human eye is able to detect even single photons Sort of. A human rod cell can be activated by a single photon. But the retinal circuitry extinguishes the noise of such isolated "pixels" as part of its pre-processing. However, the frog retina doesn't contain that neural circuitry, so frog brains can detect single photon events.
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– PM 2Ring
yesterday
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It depends on the number of photons per second (obviously). You can observe light sources which result in as few as one or two photons per second hitting the same rod, so I think that counts as single photons. You're right that a single photon hitting the retina randomly will not be visible.
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– jcupitt
16 hours ago
4
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The first sentence is completely wrong. As mentioned by CSM, you can see Andromeda Galaxy (one trillion stars), the Magellanic clouds (30 + 3 billion stars) and many clusters (e.g. Great Hercules Cluster with 300000 stars and Omega Centauri with 10 million stars) perfectly well with the naked eye. It's hard to write a credible answer after such an intro.
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– Eric Duminil
12 hours ago
add a comment |
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3 Answers
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3 Answers
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The number density of galaxies in a void is typically an order of magnitude lower than the average in the Universe (e.g. Patiri et al. 2006). In this astronomy.SE post, I estimate the number density of galaxies of magnitude $M=-17$ or brighter in the Boötes Void to be $n sim 0.004,mathrm{Mpc}^{-3}$, or $10^{-4},mathrm{Mlyr}^{-3}$ (i.e. "per cubic mega-light-year"). Hence, the typical distance to a galaxy from a random point in the Boötes Void is
$$
d = left( frac{3}{4pi n} right)^{1/3} simeq 13,mathrm{Mlyr}.
$$
That distance corresponds to a distance modulus of $mu simeq 28$, so the apparent magnitude of the galaxy would be
$$
m = M + mu simeq 11.
$$
Typically, humans cannot see objects darker than $m simeq 6.5$ (the magnitude scale is backwards, so darker means "larger values than 6.5"), although some have claimed to be able to see $msimeq8$ — still an order of magnitude brighter than the $m=11$ estimated above. Moreover, this threshold assumes point sources, whereas a galaxy has its brightness smeared out over a quite large area, lowering its surface brightness significantly!$^dagger$. Note also that, as in the rest of the Universe, galaxies in voids are not completely randomly scattered throughout space, but tend to cluster in clumps and filaments, and that the number density is smaller in the center of the void, meaning that here the typical distance to the next galaxy is larger.
Hence, you would be floating in complete darkness.$^ddagger$
$^dagger$For instance, the Andromeda galaxy has an apparent magnitude of $m=3.44$ which, if its light were concentrated in a point, would make it easily visibly even under light-polluted conditions.
$^ddagger$Your eye might be able to detect individual photons, at stated in Árpád Szendrei's answer, but that hardly counts as "seeing anything".
$endgroup$
14
$begingroup$
Well, that's an utterly terrifying concept to imagine. Thanks to everyone for making me aware of it, I am going to go lie down now
$endgroup$
– llama
yesterday
7
$begingroup$
@llama Luckily, the terrifying scenario would be over in a minute, after which you'd die from asphyxia.
$endgroup$
– pela
yesterday
$begingroup$
Maybe Hal would open the pod bay doors
$endgroup$
– Paul Young
yesterday
3
$begingroup$
Fascinating. I had no idea that such a place would exist. The Wikipedia article that's now linked from the question backs up your calculations, saying that if the Milky Way were at the centre of the Boötes Void, we wouldn't have known that there were other galaxies until the 1960s.
$endgroup$
– David Richerby
12 hours ago
1
$begingroup$
@binaryfunt Indeed, though I think it may have been a void between stars in our own galaxy i.e. between the spiral arms, rather than between galaxies.
$endgroup$
– Martin Carney
4 hours ago
|
show 3 more comments
$begingroup$
The number density of galaxies in a void is typically an order of magnitude lower than the average in the Universe (e.g. Patiri et al. 2006). In this astronomy.SE post, I estimate the number density of galaxies of magnitude $M=-17$ or brighter in the Boötes Void to be $n sim 0.004,mathrm{Mpc}^{-3}$, or $10^{-4},mathrm{Mlyr}^{-3}$ (i.e. "per cubic mega-light-year"). Hence, the typical distance to a galaxy from a random point in the Boötes Void is
$$
d = left( frac{3}{4pi n} right)^{1/3} simeq 13,mathrm{Mlyr}.
$$
That distance corresponds to a distance modulus of $mu simeq 28$, so the apparent magnitude of the galaxy would be
$$
m = M + mu simeq 11.
$$
Typically, humans cannot see objects darker than $m simeq 6.5$ (the magnitude scale is backwards, so darker means "larger values than 6.5"), although some have claimed to be able to see $msimeq8$ — still an order of magnitude brighter than the $m=11$ estimated above. Moreover, this threshold assumes point sources, whereas a galaxy has its brightness smeared out over a quite large area, lowering its surface brightness significantly!$^dagger$. Note also that, as in the rest of the Universe, galaxies in voids are not completely randomly scattered throughout space, but tend to cluster in clumps and filaments, and that the number density is smaller in the center of the void, meaning that here the typical distance to the next galaxy is larger.
Hence, you would be floating in complete darkness.$^ddagger$
$^dagger$For instance, the Andromeda galaxy has an apparent magnitude of $m=3.44$ which, if its light were concentrated in a point, would make it easily visibly even under light-polluted conditions.
$^ddagger$Your eye might be able to detect individual photons, at stated in Árpád Szendrei's answer, but that hardly counts as "seeing anything".
$endgroup$
14
$begingroup$
Well, that's an utterly terrifying concept to imagine. Thanks to everyone for making me aware of it, I am going to go lie down now
$endgroup$
– llama
yesterday
7
$begingroup$
@llama Luckily, the terrifying scenario would be over in a minute, after which you'd die from asphyxia.
$endgroup$
– pela
yesterday
$begingroup$
Maybe Hal would open the pod bay doors
$endgroup$
– Paul Young
yesterday
3
$begingroup$
Fascinating. I had no idea that such a place would exist. The Wikipedia article that's now linked from the question backs up your calculations, saying that if the Milky Way were at the centre of the Boötes Void, we wouldn't have known that there were other galaxies until the 1960s.
$endgroup$
– David Richerby
12 hours ago
1
$begingroup$
@binaryfunt Indeed, though I think it may have been a void between stars in our own galaxy i.e. between the spiral arms, rather than between galaxies.
$endgroup$
– Martin Carney
4 hours ago
|
show 3 more comments
$begingroup$
The number density of galaxies in a void is typically an order of magnitude lower than the average in the Universe (e.g. Patiri et al. 2006). In this astronomy.SE post, I estimate the number density of galaxies of magnitude $M=-17$ or brighter in the Boötes Void to be $n sim 0.004,mathrm{Mpc}^{-3}$, or $10^{-4},mathrm{Mlyr}^{-3}$ (i.e. "per cubic mega-light-year"). Hence, the typical distance to a galaxy from a random point in the Boötes Void is
$$
d = left( frac{3}{4pi n} right)^{1/3} simeq 13,mathrm{Mlyr}.
$$
That distance corresponds to a distance modulus of $mu simeq 28$, so the apparent magnitude of the galaxy would be
$$
m = M + mu simeq 11.
$$
Typically, humans cannot see objects darker than $m simeq 6.5$ (the magnitude scale is backwards, so darker means "larger values than 6.5"), although some have claimed to be able to see $msimeq8$ — still an order of magnitude brighter than the $m=11$ estimated above. Moreover, this threshold assumes point sources, whereas a galaxy has its brightness smeared out over a quite large area, lowering its surface brightness significantly!$^dagger$. Note also that, as in the rest of the Universe, galaxies in voids are not completely randomly scattered throughout space, but tend to cluster in clumps and filaments, and that the number density is smaller in the center of the void, meaning that here the typical distance to the next galaxy is larger.
Hence, you would be floating in complete darkness.$^ddagger$
$^dagger$For instance, the Andromeda galaxy has an apparent magnitude of $m=3.44$ which, if its light were concentrated in a point, would make it easily visibly even under light-polluted conditions.
$^ddagger$Your eye might be able to detect individual photons, at stated in Árpád Szendrei's answer, but that hardly counts as "seeing anything".
$endgroup$
The number density of galaxies in a void is typically an order of magnitude lower than the average in the Universe (e.g. Patiri et al. 2006). In this astronomy.SE post, I estimate the number density of galaxies of magnitude $M=-17$ or brighter in the Boötes Void to be $n sim 0.004,mathrm{Mpc}^{-3}$, or $10^{-4},mathrm{Mlyr}^{-3}$ (i.e. "per cubic mega-light-year"). Hence, the typical distance to a galaxy from a random point in the Boötes Void is
$$
d = left( frac{3}{4pi n} right)^{1/3} simeq 13,mathrm{Mlyr}.
$$
That distance corresponds to a distance modulus of $mu simeq 28$, so the apparent magnitude of the galaxy would be
$$
m = M + mu simeq 11.
$$
Typically, humans cannot see objects darker than $m simeq 6.5$ (the magnitude scale is backwards, so darker means "larger values than 6.5"), although some have claimed to be able to see $msimeq8$ — still an order of magnitude brighter than the $m=11$ estimated above. Moreover, this threshold assumes point sources, whereas a galaxy has its brightness smeared out over a quite large area, lowering its surface brightness significantly!$^dagger$. Note also that, as in the rest of the Universe, galaxies in voids are not completely randomly scattered throughout space, but tend to cluster in clumps and filaments, and that the number density is smaller in the center of the void, meaning that here the typical distance to the next galaxy is larger.
Hence, you would be floating in complete darkness.$^ddagger$
$^dagger$For instance, the Andromeda galaxy has an apparent magnitude of $m=3.44$ which, if its light were concentrated in a point, would make it easily visibly even under light-polluted conditions.
$^ddagger$Your eye might be able to detect individual photons, at stated in Árpád Szendrei's answer, but that hardly counts as "seeing anything".
edited 16 hours ago
answered yesterday
pelapela
8,4422130
8,4422130
14
$begingroup$
Well, that's an utterly terrifying concept to imagine. Thanks to everyone for making me aware of it, I am going to go lie down now
$endgroup$
– llama
yesterday
7
$begingroup$
@llama Luckily, the terrifying scenario would be over in a minute, after which you'd die from asphyxia.
$endgroup$
– pela
yesterday
$begingroup$
Maybe Hal would open the pod bay doors
$endgroup$
– Paul Young
yesterday
3
$begingroup$
Fascinating. I had no idea that such a place would exist. The Wikipedia article that's now linked from the question backs up your calculations, saying that if the Milky Way were at the centre of the Boötes Void, we wouldn't have known that there were other galaxies until the 1960s.
$endgroup$
– David Richerby
12 hours ago
1
$begingroup$
@binaryfunt Indeed, though I think it may have been a void between stars in our own galaxy i.e. between the spiral arms, rather than between galaxies.
$endgroup$
– Martin Carney
4 hours ago
|
show 3 more comments
14
$begingroup$
Well, that's an utterly terrifying concept to imagine. Thanks to everyone for making me aware of it, I am going to go lie down now
$endgroup$
– llama
yesterday
7
$begingroup$
@llama Luckily, the terrifying scenario would be over in a minute, after which you'd die from asphyxia.
$endgroup$
– pela
yesterday
$begingroup$
Maybe Hal would open the pod bay doors
$endgroup$
– Paul Young
yesterday
3
$begingroup$
Fascinating. I had no idea that such a place would exist. The Wikipedia article that's now linked from the question backs up your calculations, saying that if the Milky Way were at the centre of the Boötes Void, we wouldn't have known that there were other galaxies until the 1960s.
$endgroup$
– David Richerby
12 hours ago
1
$begingroup$
@binaryfunt Indeed, though I think it may have been a void between stars in our own galaxy i.e. between the spiral arms, rather than between galaxies.
$endgroup$
– Martin Carney
4 hours ago
14
14
$begingroup$
Well, that's an utterly terrifying concept to imagine. Thanks to everyone for making me aware of it, I am going to go lie down now
$endgroup$
– llama
yesterday
$begingroup$
Well, that's an utterly terrifying concept to imagine. Thanks to everyone for making me aware of it, I am going to go lie down now
$endgroup$
– llama
yesterday
7
7
$begingroup$
@llama Luckily, the terrifying scenario would be over in a minute, after which you'd die from asphyxia.
$endgroup$
– pela
yesterday
$begingroup$
@llama Luckily, the terrifying scenario would be over in a minute, after which you'd die from asphyxia.
$endgroup$
– pela
yesterday
$begingroup$
Maybe Hal would open the pod bay doors
$endgroup$
– Paul Young
yesterday
$begingroup$
Maybe Hal would open the pod bay doors
$endgroup$
– Paul Young
yesterday
3
3
$begingroup$
Fascinating. I had no idea that such a place would exist. The Wikipedia article that's now linked from the question backs up your calculations, saying that if the Milky Way were at the centre of the Boötes Void, we wouldn't have known that there were other galaxies until the 1960s.
$endgroup$
– David Richerby
12 hours ago
$begingroup$
Fascinating. I had no idea that such a place would exist. The Wikipedia article that's now linked from the question backs up your calculations, saying that if the Milky Way were at the centre of the Boötes Void, we wouldn't have known that there were other galaxies until the 1960s.
$endgroup$
– David Richerby
12 hours ago
1
1
$begingroup$
@binaryfunt Indeed, though I think it may have been a void between stars in our own galaxy i.e. between the spiral arms, rather than between galaxies.
$endgroup$
– Martin Carney
4 hours ago
$begingroup$
@binaryfunt Indeed, though I think it may have been a void between stars in our own galaxy i.e. between the spiral arms, rather than between galaxies.
$endgroup$
– Martin Carney
4 hours ago
|
show 3 more comments
$begingroup$
From the Wikipedia page on the Boötes void (the same that you linked to in your question):
According to astronomer Greg Aldering, the scale of the void is such that "If the Milky Way had been in the center of the Boötes void, we wouldn't have known there were other galaxies until the 1960s."
(The original article can be found thanks to the Wayback Machine.)
This means that if we were in the center of the Boötes void, we wouldn't be able to see any galaxies with the naked eye, and not even with some telescopes. Again according to Wikipedia, telescopes were invented at the beginning of the 17th century, radio telescopes in the 1930s and infrared telescopes in the 1960s.
New contributor
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1
$begingroup$
That quote and that I share Llama’s reaction to pela’s answer are what inspired the question.
$endgroup$
– Paul Young
yesterday
$begingroup$
Note that the Wikipedia page wasn't linked in the original version of the question -- that was added by somebody else, later.
$endgroup$
– David Richerby
12 hours ago
$begingroup$
hence the OP's upvote to Fabio ...
$endgroup$
– Paul Young
8 hours ago
add a comment |
$begingroup$
From the Wikipedia page on the Boötes void (the same that you linked to in your question):
According to astronomer Greg Aldering, the scale of the void is such that "If the Milky Way had been in the center of the Boötes void, we wouldn't have known there were other galaxies until the 1960s."
(The original article can be found thanks to the Wayback Machine.)
This means that if we were in the center of the Boötes void, we wouldn't be able to see any galaxies with the naked eye, and not even with some telescopes. Again according to Wikipedia, telescopes were invented at the beginning of the 17th century, radio telescopes in the 1930s and infrared telescopes in the 1960s.
New contributor
$endgroup$
1
$begingroup$
That quote and that I share Llama’s reaction to pela’s answer are what inspired the question.
$endgroup$
– Paul Young
yesterday
$begingroup$
Note that the Wikipedia page wasn't linked in the original version of the question -- that was added by somebody else, later.
$endgroup$
– David Richerby
12 hours ago
$begingroup$
hence the OP's upvote to Fabio ...
$endgroup$
– Paul Young
8 hours ago
add a comment |
$begingroup$
From the Wikipedia page on the Boötes void (the same that you linked to in your question):
According to astronomer Greg Aldering, the scale of the void is such that "If the Milky Way had been in the center of the Boötes void, we wouldn't have known there were other galaxies until the 1960s."
(The original article can be found thanks to the Wayback Machine.)
This means that if we were in the center of the Boötes void, we wouldn't be able to see any galaxies with the naked eye, and not even with some telescopes. Again according to Wikipedia, telescopes were invented at the beginning of the 17th century, radio telescopes in the 1930s and infrared telescopes in the 1960s.
New contributor
$endgroup$
From the Wikipedia page on the Boötes void (the same that you linked to in your question):
According to astronomer Greg Aldering, the scale of the void is such that "If the Milky Way had been in the center of the Boötes void, we wouldn't have known there were other galaxies until the 1960s."
(The original article can be found thanks to the Wayback Machine.)
This means that if we were in the center of the Boötes void, we wouldn't be able to see any galaxies with the naked eye, and not even with some telescopes. Again according to Wikipedia, telescopes were invented at the beginning of the 17th century, radio telescopes in the 1930s and infrared telescopes in the 1960s.
New contributor
New contributor
answered yesterday
Fabio TuratiFabio Turati
1714
1714
New contributor
New contributor
1
$begingroup$
That quote and that I share Llama’s reaction to pela’s answer are what inspired the question.
$endgroup$
– Paul Young
yesterday
$begingroup$
Note that the Wikipedia page wasn't linked in the original version of the question -- that was added by somebody else, later.
$endgroup$
– David Richerby
12 hours ago
$begingroup$
hence the OP's upvote to Fabio ...
$endgroup$
– Paul Young
8 hours ago
add a comment |
1
$begingroup$
That quote and that I share Llama’s reaction to pela’s answer are what inspired the question.
$endgroup$
– Paul Young
yesterday
$begingroup$
Note that the Wikipedia page wasn't linked in the original version of the question -- that was added by somebody else, later.
$endgroup$
– David Richerby
12 hours ago
$begingroup$
hence the OP's upvote to Fabio ...
$endgroup$
– Paul Young
8 hours ago
1
1
$begingroup$
That quote and that I share Llama’s reaction to pela’s answer are what inspired the question.
$endgroup$
– Paul Young
yesterday
$begingroup$
That quote and that I share Llama’s reaction to pela’s answer are what inspired the question.
$endgroup$
– Paul Young
yesterday
$begingroup$
Note that the Wikipedia page wasn't linked in the original version of the question -- that was added by somebody else, later.
$endgroup$
– David Richerby
12 hours ago
$begingroup$
Note that the Wikipedia page wasn't linked in the original version of the question -- that was added by somebody else, later.
$endgroup$
– David Richerby
12 hours ago
$begingroup$
hence the OP's upvote to Fabio ...
$endgroup$
– Paul Young
8 hours ago
$begingroup$
hence the OP's upvote to Fabio ...
$endgroup$
– Paul Young
8 hours ago
add a comment |
$begingroup$
In fact you would see only individual stars. Like on Earth, you can only see individual stars, and no galaxies with the naked eye. Why? Because galaxies are too dim as a whole.
Now, if you would just float in empty space in the void you would be better off then on Earth. It is because here on Earth there is some light pollution.
But in the void, there is basically no light pollution, so you could see even single photons arriving from far away giant stars.
And yes, the human eye is able to detect even single photons.
By the way, all the stars that you can see with the naked eye from Earth are from the Milky Way. But again, that is too because of the light pollution and because our night sky even if there would be no light pollution here on Earth would be filled with brighter start from the Milky way. Our eyes would get used to that, and the start from other galaxies would just appear too dim to see.
Now on the dark side of the moon it would be a little different, but only that there is no light pollution like on Earth. Still, from the dark side of the Moon you could still only see stars from the Milky way.
Now in the void in your case, I think it is different. It is so dark and void, that even a single photon coming from a far away large star would be visible to our eyes that get used to the darkness.
Please see here:
Do all the individual stars that we can see in the night sky belong to Milky Way?
$endgroup$
9
$begingroup$
You can see Andromeda with the naked eye, under optimal conditions. It's mag +3.44. Sagittarius Dwarf Spheroidal Galaxy and M33 should also be visible
$endgroup$
– CSM
yesterday
7
$begingroup$
the human eye is able to detect even single photons Sort of. A human rod cell can be activated by a single photon. But the retinal circuitry extinguishes the noise of such isolated "pixels" as part of its pre-processing. However, the frog retina doesn't contain that neural circuitry, so frog brains can detect single photon events.
$endgroup$
– PM 2Ring
yesterday
$begingroup$
It depends on the number of photons per second (obviously). You can observe light sources which result in as few as one or two photons per second hitting the same rod, so I think that counts as single photons. You're right that a single photon hitting the retina randomly will not be visible.
$endgroup$
– jcupitt
16 hours ago
4
$begingroup$
The first sentence is completely wrong. As mentioned by CSM, you can see Andromeda Galaxy (one trillion stars), the Magellanic clouds (30 + 3 billion stars) and many clusters (e.g. Great Hercules Cluster with 300000 stars and Omega Centauri with 10 million stars) perfectly well with the naked eye. It's hard to write a credible answer after such an intro.
$endgroup$
– Eric Duminil
12 hours ago
add a comment |
$begingroup$
In fact you would see only individual stars. Like on Earth, you can only see individual stars, and no galaxies with the naked eye. Why? Because galaxies are too dim as a whole.
Now, if you would just float in empty space in the void you would be better off then on Earth. It is because here on Earth there is some light pollution.
But in the void, there is basically no light pollution, so you could see even single photons arriving from far away giant stars.
And yes, the human eye is able to detect even single photons.
By the way, all the stars that you can see with the naked eye from Earth are from the Milky Way. But again, that is too because of the light pollution and because our night sky even if there would be no light pollution here on Earth would be filled with brighter start from the Milky way. Our eyes would get used to that, and the start from other galaxies would just appear too dim to see.
Now on the dark side of the moon it would be a little different, but only that there is no light pollution like on Earth. Still, from the dark side of the Moon you could still only see stars from the Milky way.
Now in the void in your case, I think it is different. It is so dark and void, that even a single photon coming from a far away large star would be visible to our eyes that get used to the darkness.
Please see here:
Do all the individual stars that we can see in the night sky belong to Milky Way?
$endgroup$
9
$begingroup$
You can see Andromeda with the naked eye, under optimal conditions. It's mag +3.44. Sagittarius Dwarf Spheroidal Galaxy and M33 should also be visible
$endgroup$
– CSM
yesterday
7
$begingroup$
the human eye is able to detect even single photons Sort of. A human rod cell can be activated by a single photon. But the retinal circuitry extinguishes the noise of such isolated "pixels" as part of its pre-processing. However, the frog retina doesn't contain that neural circuitry, so frog brains can detect single photon events.
$endgroup$
– PM 2Ring
yesterday
$begingroup$
It depends on the number of photons per second (obviously). You can observe light sources which result in as few as one or two photons per second hitting the same rod, so I think that counts as single photons. You're right that a single photon hitting the retina randomly will not be visible.
$endgroup$
– jcupitt
16 hours ago
4
$begingroup$
The first sentence is completely wrong. As mentioned by CSM, you can see Andromeda Galaxy (one trillion stars), the Magellanic clouds (30 + 3 billion stars) and many clusters (e.g. Great Hercules Cluster with 300000 stars and Omega Centauri with 10 million stars) perfectly well with the naked eye. It's hard to write a credible answer after such an intro.
$endgroup$
– Eric Duminil
12 hours ago
add a comment |
$begingroup$
In fact you would see only individual stars. Like on Earth, you can only see individual stars, and no galaxies with the naked eye. Why? Because galaxies are too dim as a whole.
Now, if you would just float in empty space in the void you would be better off then on Earth. It is because here on Earth there is some light pollution.
But in the void, there is basically no light pollution, so you could see even single photons arriving from far away giant stars.
And yes, the human eye is able to detect even single photons.
By the way, all the stars that you can see with the naked eye from Earth are from the Milky Way. But again, that is too because of the light pollution and because our night sky even if there would be no light pollution here on Earth would be filled with brighter start from the Milky way. Our eyes would get used to that, and the start from other galaxies would just appear too dim to see.
Now on the dark side of the moon it would be a little different, but only that there is no light pollution like on Earth. Still, from the dark side of the Moon you could still only see stars from the Milky way.
Now in the void in your case, I think it is different. It is so dark and void, that even a single photon coming from a far away large star would be visible to our eyes that get used to the darkness.
Please see here:
Do all the individual stars that we can see in the night sky belong to Milky Way?
$endgroup$
In fact you would see only individual stars. Like on Earth, you can only see individual stars, and no galaxies with the naked eye. Why? Because galaxies are too dim as a whole.
Now, if you would just float in empty space in the void you would be better off then on Earth. It is because here on Earth there is some light pollution.
But in the void, there is basically no light pollution, so you could see even single photons arriving from far away giant stars.
And yes, the human eye is able to detect even single photons.
By the way, all the stars that you can see with the naked eye from Earth are from the Milky Way. But again, that is too because of the light pollution and because our night sky even if there would be no light pollution here on Earth would be filled with brighter start from the Milky way. Our eyes would get used to that, and the start from other galaxies would just appear too dim to see.
Now on the dark side of the moon it would be a little different, but only that there is no light pollution like on Earth. Still, from the dark side of the Moon you could still only see stars from the Milky way.
Now in the void in your case, I think it is different. It is so dark and void, that even a single photon coming from a far away large star would be visible to our eyes that get used to the darkness.
Please see here:
Do all the individual stars that we can see in the night sky belong to Milky Way?
answered yesterday
Árpád SzendreiÁrpád Szendrei
4,4151624
4,4151624
9
$begingroup$
You can see Andromeda with the naked eye, under optimal conditions. It's mag +3.44. Sagittarius Dwarf Spheroidal Galaxy and M33 should also be visible
$endgroup$
– CSM
yesterday
7
$begingroup$
the human eye is able to detect even single photons Sort of. A human rod cell can be activated by a single photon. But the retinal circuitry extinguishes the noise of such isolated "pixels" as part of its pre-processing. However, the frog retina doesn't contain that neural circuitry, so frog brains can detect single photon events.
$endgroup$
– PM 2Ring
yesterday
$begingroup$
It depends on the number of photons per second (obviously). You can observe light sources which result in as few as one or two photons per second hitting the same rod, so I think that counts as single photons. You're right that a single photon hitting the retina randomly will not be visible.
$endgroup$
– jcupitt
16 hours ago
4
$begingroup$
The first sentence is completely wrong. As mentioned by CSM, you can see Andromeda Galaxy (one trillion stars), the Magellanic clouds (30 + 3 billion stars) and many clusters (e.g. Great Hercules Cluster with 300000 stars and Omega Centauri with 10 million stars) perfectly well with the naked eye. It's hard to write a credible answer after such an intro.
$endgroup$
– Eric Duminil
12 hours ago
add a comment |
9
$begingroup$
You can see Andromeda with the naked eye, under optimal conditions. It's mag +3.44. Sagittarius Dwarf Spheroidal Galaxy and M33 should also be visible
$endgroup$
– CSM
yesterday
7
$begingroup$
the human eye is able to detect even single photons Sort of. A human rod cell can be activated by a single photon. But the retinal circuitry extinguishes the noise of such isolated "pixels" as part of its pre-processing. However, the frog retina doesn't contain that neural circuitry, so frog brains can detect single photon events.
$endgroup$
– PM 2Ring
yesterday
$begingroup$
It depends on the number of photons per second (obviously). You can observe light sources which result in as few as one or two photons per second hitting the same rod, so I think that counts as single photons. You're right that a single photon hitting the retina randomly will not be visible.
$endgroup$
– jcupitt
16 hours ago
4
$begingroup$
The first sentence is completely wrong. As mentioned by CSM, you can see Andromeda Galaxy (one trillion stars), the Magellanic clouds (30 + 3 billion stars) and many clusters (e.g. Great Hercules Cluster with 300000 stars and Omega Centauri with 10 million stars) perfectly well with the naked eye. It's hard to write a credible answer after such an intro.
$endgroup$
– Eric Duminil
12 hours ago
9
9
$begingroup$
You can see Andromeda with the naked eye, under optimal conditions. It's mag +3.44. Sagittarius Dwarf Spheroidal Galaxy and M33 should also be visible
$endgroup$
– CSM
yesterday
$begingroup$
You can see Andromeda with the naked eye, under optimal conditions. It's mag +3.44. Sagittarius Dwarf Spheroidal Galaxy and M33 should also be visible
$endgroup$
– CSM
yesterday
7
7
$begingroup$
the human eye is able to detect even single photons Sort of. A human rod cell can be activated by a single photon. But the retinal circuitry extinguishes the noise of such isolated "pixels" as part of its pre-processing. However, the frog retina doesn't contain that neural circuitry, so frog brains can detect single photon events.
$endgroup$
– PM 2Ring
yesterday
$begingroup$
the human eye is able to detect even single photons Sort of. A human rod cell can be activated by a single photon. But the retinal circuitry extinguishes the noise of such isolated "pixels" as part of its pre-processing. However, the frog retina doesn't contain that neural circuitry, so frog brains can detect single photon events.
$endgroup$
– PM 2Ring
yesterday
$begingroup$
It depends on the number of photons per second (obviously). You can observe light sources which result in as few as one or two photons per second hitting the same rod, so I think that counts as single photons. You're right that a single photon hitting the retina randomly will not be visible.
$endgroup$
– jcupitt
16 hours ago
$begingroup$
It depends on the number of photons per second (obviously). You can observe light sources which result in as few as one or two photons per second hitting the same rod, so I think that counts as single photons. You're right that a single photon hitting the retina randomly will not be visible.
$endgroup$
– jcupitt
16 hours ago
4
4
$begingroup$
The first sentence is completely wrong. As mentioned by CSM, you can see Andromeda Galaxy (one trillion stars), the Magellanic clouds (30 + 3 billion stars) and many clusters (e.g. Great Hercules Cluster with 300000 stars and Omega Centauri with 10 million stars) perfectly well with the naked eye. It's hard to write a credible answer after such an intro.
$endgroup$
– Eric Duminil
12 hours ago
$begingroup$
The first sentence is completely wrong. As mentioned by CSM, you can see Andromeda Galaxy (one trillion stars), the Magellanic clouds (30 + 3 billion stars) and many clusters (e.g. Great Hercules Cluster with 300000 stars and Omega Centauri with 10 million stars) perfectly well with the naked eye. It's hard to write a credible answer after such an intro.
$endgroup$
– Eric Duminil
12 hours ago
add a comment |
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$begingroup$
The Bootes void has some galaxies in it, and I don't know if it has much of a centre. IMO this needs to be more specific about the conditions.
$endgroup$
– JMac
yesterday
5
$begingroup$
Let's pick the spot that is furthest from any galaxy.
$endgroup$
– Paul Young
yesterday
10
$begingroup$
@PaulYoung so you're saying "if there's a bright center to the Universe, you're at the [point] it's farthest from"?
$endgroup$
– MikeTheLiar
yesterday
2
$begingroup$
@MikeTheLiar seems more like "let's get as far away from as many galaxies as possible"
$endgroup$
– immibis
yesterday