Mixing
Interstellar “reefsâ€, plausibility and detection
Clash Royale CLAN TAG#URR8PPP
up vote
2
down vote
favorite
Most of the interstellar medium is, as far as we can tell with current technology, pretty empty and most of what is there is in the form of single atoms or tiny particles only a few molecules across. Is it plausible then to have denser regions of matter in deep interstellar space, possibly the remnants of long dead star systems? And if these areas did exist how close would we need to get with current technology to detect them?
For the purposes of giving a coherent answer assume that the areas in question are similar in volume, number of objects, spatial density, and overall mass to Jupiter's L4Trojan Asteroids and have similarly low albedos (0.04 to 0.12). Note that for the purposes of detection these regions would be outside the Heliosphere of all the nearest stars so the amount of radiation available for them to reflect or occlude will be correspondingly low.
Note carefully that I'm not asking if we can detect something like the Trojans since obviously we can we're in the process of counting them; I'm asking how close we have to be to detect a scatter of such small dark objects when they are far from the nearest star.
reality-check interstellar-travel
asked 3 hours ago
Ash
24k463137
add a comment |Â
up vote
2
down vote
favorite
Most of the interstellar medium is, as far as we can tell with current technology, pretty empty and most of what is there is in the form of single atoms or tiny particles only a few molecules across. Is it plausible then to have denser regions of matter in deep interstellar space, possibly the remnants of long dead star systems? And if these areas did exist how close would we need to get with current technology to detect them?
For the purposes of giving a coherent answer assume that the areas in question are similar in volume, number of objects, spatial density, and overall mass to Jupiter's L4Trojan Asteroids and have similarly low albedos (0.04 to 0.12). Note that for the purposes of detection these regions would be outside the Heliosphere of all the nearest stars so the amount of radiation available for them to reflect or occlude will be correspondingly low.
Note carefully that I'm not asking if we can detect something like the Trojans since obviously we can we're in the process of counting them; I'm asking how close we have to be to detect a scatter of such small dark objects when they are far from the nearest star.
reality-check interstellar-travel
asked 3 hours ago
Ash
24k463137
add a comment |Â
up vote
2
down vote
favorite
up vote
2
down vote
favorite
Most of the interstellar medium is, as far as we can tell with current technology, pretty empty and most of what is there is in the form of single atoms or tiny particles only a few molecules across. Is it plausible then to have denser regions of matter in deep interstellar space, possibly the remnants of long dead star systems? And if these areas did exist how close would we need to get with current technology to detect them?
For the purposes of giving a coherent answer assume that the areas in question are similar in volume, number of objects, spatial density, and overall mass to Jupiter's L4Trojan Asteroids and have similarly low albedos (0.04 to 0.12). Note that for the purposes of detection these regions would be outside the Heliosphere of all the nearest stars so the amount of radiation available for them to reflect or occlude will be correspondingly low.
Note carefully that I'm not asking if we can detect something like the Trojans since obviously we can we're in the process of counting them; I'm asking how close we have to be to detect a scatter of such small dark objects when they are far from the nearest star.
reality-check interstellar-travel
asked 3 hours ago
Ash
24k463137
Most of the interstellar medium is, as far as we can tell with current technology, pretty empty and most of what is there is in the form of single atoms or tiny particles only a few molecules across. Is it plausible then to have denser regions of matter in deep interstellar space, possibly the remnants of long dead star systems? And if these areas did exist how close would we need to get with current technology to detect them?
For the purposes of giving a coherent answer assume that the areas in question are similar in volume, number of objects, spatial density, and overall mass to Jupiter's L4Trojan Asteroids and have similarly low albedos (0.04 to 0.12). Note that for the purposes of detection these regions would be outside the Heliosphere of all the nearest stars so the amount of radiation available for them to reflect or occlude will be correspondingly low.
Note carefully that I'm not asking if we can detect something like the Trojans since obviously we can we're in the process of counting them; I'm asking how close we have to be to detect a scatter of such small dark objects when they are far from the nearest star.
reality-check interstellar-travel
reality-check interstellar-travel
asked 3 hours ago
Ash
24k463137
asked 3 hours ago
Ash
24k463137
edited 2 hours ago
asked 3 hours ago
Ash
24k463137
asked 3 hours ago
Ash
24k463137
asked 3 hours ago
Ash
24k463137
24k463137
add a comment |Â
add a comment |Â
2 Answers
2
active
oldest
votes
up vote
4
down vote
Answering the second part of your question on how to detect such objects: Since there is not much light for those objects to reflect, the best available tool would be radar astronomy, where you effectively provide your own light-source in the form of radar waves.
The rest then just is numbers. I'm not sure what the current state of the art is, but I can try to give a rough estimation. Wikipedia mentions the Galilean moons as objects that we have observed. So say that we can observe a 3000km diameter object at 5AU. The largest trojans are about 100km in size which leaves us with about $1/30^2=1/900$th of the surface. I'm not sure about the difference in albedo, since we are not using visible light, so I'll just assume it to be roughly the same. Radar loses signal strength with the fourth power of the distance (squared on the way out, then again squared on the way back in), so we'll get about $sqrt[4]1/900=sqrt1/30approx1/5$th of the distance, in other words about 1 AU of range.
Of course you specify today's technology while talking about interstellar travel. If you are willing to lift a sufficient amount of mass into space, today's technology could build some quite impressive radar dishes when not having to deal with pesky gravity or securing sufficient funding for research without direct application. So 10 or even 100 AU might be feasible as well.
answered 1 hour ago
mlk
57916
add a comment |Â
up vote
0
down vote
Yes, many rogue planets have been discovered, and they are believed to be very common, with hundreds of millions or billions in our galaxy. To answer the rest of your question, they can be detected with our current technology, and they have been.
If you didn’t mean to include rogue planets in your scope, you will have to rephrase the question, since a planet is certainly a “dense region of matterâ€Â.
answered 2 hours ago
Mike Scott
10.2k32045
An earthlike planet is both far too large and far too small to fit the parameters of the question as originally written. The Trojans cover a vast area of the solar system but with a mass less than 1% that of Earth's moon. Furthermore the 16 known rogue planets are all super jovians massing thousands of times more than the Earth.
– Ash
2 hours ago
add a comment |Â
2 Answers
2
active
oldest
votes
2 Answers
2
active
oldest
votes
active
oldest
votes
active
oldest
votes
up vote
4
down vote
Answering the second part of your question on how to detect such objects: Since there is not much light for those objects to reflect, the best available tool would be radar astronomy, where you effectively provide your own light-source in the form of radar waves.
The rest then just is numbers. I'm not sure what the current state of the art is, but I can try to give a rough estimation. Wikipedia mentions the Galilean moons as objects that we have observed. So say that we can observe a 3000km diameter object at 5AU. The largest trojans are about 100km in size which leaves us with about $1/30^2=1/900$th of the surface. I'm not sure about the difference in albedo, since we are not using visible light, so I'll just assume it to be roughly the same. Radar loses signal strength with the fourth power of the distance (squared on the way out, then again squared on the way back in), so we'll get about $sqrt[4]1/900=sqrt1/30approx1/5$th of the distance, in other words about 1 AU of range.
Of course you specify today's technology while talking about interstellar travel. If you are willing to lift a sufficient amount of mass into space, today's technology could build some quite impressive radar dishes when not having to deal with pesky gravity or securing sufficient funding for research without direct application. So 10 or even 100 AU might be feasible as well.
answered 1 hour ago
mlk
57916
add a comment |Â
up vote
4
down vote
Answering the second part of your question on how to detect such objects: Since there is not much light for those objects to reflect, the best available tool would be radar astronomy, where you effectively provide your own light-source in the form of radar waves.
The rest then just is numbers. I'm not sure what the current state of the art is, but I can try to give a rough estimation. Wikipedia mentions the Galilean moons as objects that we have observed. So say that we can observe a 3000km diameter object at 5AU. The largest trojans are about 100km in size which leaves us with about $1/30^2=1/900$th of the surface. I'm not sure about the difference in albedo, since we are not using visible light, so I'll just assume it to be roughly the same. Radar loses signal strength with the fourth power of the distance (squared on the way out, then again squared on the way back in), so we'll get about $sqrt[4]1/900=sqrt1/30approx1/5$th of the distance, in other words about 1 AU of range.
Of course you specify today's technology while talking about interstellar travel. If you are willing to lift a sufficient amount of mass into space, today's technology could build some quite impressive radar dishes when not having to deal with pesky gravity or securing sufficient funding for research without direct application. So 10 or even 100 AU might be feasible as well.
answered 1 hour ago
mlk
57916
add a comment |Â
up vote
4
down vote
up vote
4
down vote
Answering the second part of your question on how to detect such objects: Since there is not much light for those objects to reflect, the best available tool would be radar astronomy, where you effectively provide your own light-source in the form of radar waves.
The rest then just is numbers. I'm not sure what the current state of the art is, but I can try to give a rough estimation. Wikipedia mentions the Galilean moons as objects that we have observed. So say that we can observe a 3000km diameter object at 5AU. The largest trojans are about 100km in size which leaves us with about $1/30^2=1/900$th of the surface. I'm not sure about the difference in albedo, since we are not using visible light, so I'll just assume it to be roughly the same. Radar loses signal strength with the fourth power of the distance (squared on the way out, then again squared on the way back in), so we'll get about $sqrt[4]1/900=sqrt1/30approx1/5$th of the distance, in other words about 1 AU of range.
Of course you specify today's technology while talking about interstellar travel. If you are willing to lift a sufficient amount of mass into space, today's technology could build some quite impressive radar dishes when not having to deal with pesky gravity or securing sufficient funding for research without direct application. So 10 or even 100 AU might be feasible as well.
answered 1 hour ago
mlk
57916
Answering the second part of your question on how to detect such objects: Since there is not much light for those objects to reflect, the best available tool would be radar astronomy, where you effectively provide your own light-source in the form of radar waves.
The rest then just is numbers. I'm not sure what the current state of the art is, but I can try to give a rough estimation. Wikipedia mentions the Galilean moons as objects that we have observed. So say that we can observe a 3000km diameter object at 5AU. The largest trojans are about 100km in size which leaves us with about $1/30^2=1/900$th of the surface. I'm not sure about the difference in albedo, since we are not using visible light, so I'll just assume it to be roughly the same. Radar loses signal strength with the fourth power of the distance (squared on the way out, then again squared on the way back in), so we'll get about $sqrt[4]1/900=sqrt1/30approx1/5$th of the distance, in other words about 1 AU of range.
Of course you specify today's technology while talking about interstellar travel. If you are willing to lift a sufficient amount of mass into space, today's technology could build some quite impressive radar dishes when not having to deal with pesky gravity or securing sufficient funding for research without direct application. So 10 or even 100 AU might be feasible as well.
answered 1 hour ago
mlk
57916
answered 1 hour ago
mlk
57916
answered 1 hour ago
mlk
57916
answered 1 hour ago
mlk
57916
57916
add a comment |Â
add a comment |Â
up vote
0
down vote
Yes, many rogue planets have been discovered, and they are believed to be very common, with hundreds of millions or billions in our galaxy. To answer the rest of your question, they can be detected with our current technology, and they have been.
If you didn’t mean to include rogue planets in your scope, you will have to rephrase the question, since a planet is certainly a “dense region of matterâ€Â.
answered 2 hours ago
Mike Scott
10.2k32045
An earthlike planet is both far too large and far too small to fit the parameters of the question as originally written. The Trojans cover a vast area of the solar system but with a mass less than 1% that of Earth's moon. Furthermore the 16 known rogue planets are all super jovians massing thousands of times more than the Earth.
– Ash
2 hours ago
add a comment |Â
up vote
0
down vote
Yes, many rogue planets have been discovered, and they are believed to be very common, with hundreds of millions or billions in our galaxy. To answer the rest of your question, they can be detected with our current technology, and they have been.
If you didn’t mean to include rogue planets in your scope, you will have to rephrase the question, since a planet is certainly a “dense region of matterâ€Â.
answered 2 hours ago
Mike Scott
10.2k32045
An earthlike planet is both far too large and far too small to fit the parameters of the question as originally written. The Trojans cover a vast area of the solar system but with a mass less than 1% that of Earth's moon. Furthermore the 16 known rogue planets are all super jovians massing thousands of times more than the Earth.
– Ash
2 hours ago
add a comment |Â
up vote
0
down vote
up vote
0
down vote
Yes, many rogue planets have been discovered, and they are believed to be very common, with hundreds of millions or billions in our galaxy. To answer the rest of your question, they can be detected with our current technology, and they have been.
If you didn’t mean to include rogue planets in your scope, you will have to rephrase the question, since a planet is certainly a “dense region of matterâ€Â.
answered 2 hours ago
Mike Scott
10.2k32045
Yes, many rogue planets have been discovered, and they are believed to be very common, with hundreds of millions or billions in our galaxy. To answer the rest of your question, they can be detected with our current technology, and they have been.
If you didn’t mean to include rogue planets in your scope, you will have to rephrase the question, since a planet is certainly a “dense region of matterâ€Â.
answered 2 hours ago
Mike Scott
10.2k32045
answered 2 hours ago
Mike Scott
10.2k32045
answered 2 hours ago
Mike Scott
10.2k32045
answered 2 hours ago
Mike Scott
10.2k32045
10.2k32045
An earthlike planet is both far too large and far too small to fit the parameters of the question as originally written. The Trojans cover a vast area of the solar system but with a mass less than 1% that of Earth's moon. Furthermore the 16 known rogue planets are all super jovians massing thousands of times more than the Earth.
– Ash
2 hours ago
add a comment |Â
An earthlike planet is both far too large and far too small to fit the parameters of the question as originally written. The Trojans cover a vast area of the solar system but with a mass less than 1% that of Earth's moon. Furthermore the 16 known rogue planets are all super jovians massing thousands of times more than the Earth.
– Ash
2 hours ago
An earthlike planet is both far too large and far too small to fit the parameters of the question as originally written. The Trojans cover a vast area of the solar system but with a mass less than 1% that of Earth's moon. Furthermore the 16 known rogue planets are all super jovians massing thousands of times more than the Earth.
– Ash
2 hours ago
An earthlike planet is both far too large and far too small to fit the parameters of the question as originally written. The Trojans cover a vast area of the solar system but with a mass less than 1% that of Earth's moon. Furthermore the 16 known rogue planets are all super jovians massing thousands of times more than the Earth.
– Ash
2 hours ago
add a comment |Â
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
StackExchange.ready(
function ()
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fworldbuilding.stackexchange.com%2fquestions%2f128735%2finterstellar-reefs-plausibility-and-detection%23new-answer', 'question_page');
);
Post as a guest
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
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
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
