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Bolthole location

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Re: Intersect map
Post by isaac_newton   » Tue Nov 05, 2019 4:35 am

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Thank you :-)

as always very helpful!
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Re: Bolthole location
Post by TFLYTSNBN   » Tue Nov 05, 2019 12:29 pm

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Joat42 wrote:
TFLYTSNBN wrote:Did they forget about radio in the Honorverse?

With Bolthole only a few hundred light years from almost every major solar system, someone should have noticed their radio emissions.

That hypotheses needs 5 elements to work:
1. Someone needs to listen with quite sensitive equipment.
2. The colonists would have had to foreseen the need to build a transmitter before they where volcano-blasted back to the stone-age.
3. The listener would have to know that they didn't colonize Calvin's Hope so they could point their equipment at the new system.
4. There had to be some system setup before they left that a radio-message would arrive at around 750-770 PD (like ~700 years after they left).
5. Angus Calvin chose the target system for the specific reason of getting away from Earth and it's politics, which would have been a lie from the beginning.



This might be a valid argument prior to the colony ship discovering that their planet had been pasturized. When they had to move on with only limited fuel for course change, they probably would have decided that they might need some help or resupply.

Detecting radio emissions over interstellar distances is not a daunting task. It is certain that everyone within 100+ LY of Earth knows we are here. It is not unlikely to suggest that a Cee-fractional projectile has already been launched to eradicate the infestation.

Earth in the Honorverse would almost certainly be vigilant for radio emissions. Aside from looking for lost colonies, humanity would be looking for emerging alien civilizations.

I would also want to monitor human colonies to ensure that no fanatics were launching a relativistic attack using their colony ship.
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Re: Bolthole location
Post by Joat42   » Tue Nov 05, 2019 2:31 pm

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TFLYTSNBN wrote:
TFLYTSNBN wrote:Did they forget about radio in the Honorverse?

With Bolthole only a few hundred light years from almost every major solar system, someone should have noticed their radio emissions.
Joat42 wrote:That hypotheses needs 5 elements to work:
1. Someone needs to listen with quite sensitive equipment.
2. The colonists would have had to foreseen the need to build a transmitter before they where volcano-blasted back to the stone-age.
3. The listener would have to know that they didn't colonize Calvin's Hope so they could point their equipment at the new system.
4. There had to be some system setup before they left that a radio-message would arrive at around 750-770 PD (like ~700 years after they left).
5. Angus Calvin chose the target system for the specific reason of getting away from Earth and it's politics, which would have been a lie from the beginning.

This might be a valid argument prior to the colony ship discovering that their planet had been pasturized. When they had to move on with only limited fuel for course change, they probably would have decided that they might need some help or resupply.

Detecting radio emissions over interstellar distances is not a daunting task. It is certain that everyone within 100+ LY of Earth knows we are here. It is not unlikely to suggest that a Cee-fractional projectile has already been launched to eradicate the infestation.

Earth in the Honorverse would almost certainly be vigilant for radio emissions. Aside from looking for lost colonies, humanity would be looking for emerging alien civilizations.

I would also want to monitor human colonies to ensure that no fanatics were launching a relativistic attack using their colony ship.

Detecting radio emissions over interstellar distances takes time and patience, not something relatively newly established colonies have the resources for. And Earth? Well, forget about them since the timeline tells us that they where just gearing up to the Final War; I doubt anyone there where interested in looking for signals from space.

And resupply? A supply run would take at least 400 years to reach them after a signal was sent, but who would foot the bill for it then? It's not like they can have a discussion who would pay for it.

---
Jack of all trades and destructive tinkerer.


Anyone who have simple solutions for complex problems is a fool.
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Re: Bolthole location
Post by ThinksMarkedly   » Tue Nov 05, 2019 3:44 pm

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Joat42 wrote:
TFLYTSNBN wrote:Detecting radio emissions over interstellar distances is not a daunting task. It is certain that everyone within 100+ LY of Earth knows we are here. It is not unlikely to suggest that a Cee-fractional projectile has already been launched to eradicate the infestation.

Detecting radio emissions over interstellar distances takes time and patience, not something relatively newly established colonies have the resources for. And Earth? Well, forget about them since the timeline tells us that they where just gearing up to the Final War; I doubt anyone there where interested in looking for signals from space.


Right, there's no guarantee that anyone beyond 50 light-years of Earth can detect us. Yes, we've been making noise for 100 years, but attenuation, under the best circumstances, is quadratic over distance. And it's not under the best circumstances because there's a lot of dust in interstellar space. However rarefied it is, we're talking about over a quadrillion kilometres in a straight line.

The Calvin's Hope expedition could not land on the planet. So all they had available were their own on-board transmitters, which are likely not powerful enough to transmit back to Earth or Beowulf. If they had landed, they might have been able to build the infrastructure for a more powerful transmitter which would let them keep in contact with the rest of the human species.

That was not an option in Sanctuary. They arrived with very little runway left in their resources, to a planet that was hidden behind a dust cloud anyway, and they had their second incident not long thereafter.

We also know from Grayson that certain factions didn't want to be found, so they would not be attempting to transmit anyway.
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Re: Bolthole location
Post by TFLYTSNBN   » Wed Nov 06, 2019 5:04 pm

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ThinksMarkedly wrote:
Joat42 wrote:


Detecting radio emissions over interstellar distances takes time and patience, not something relatively newly established colonies have the resources for. And Earth? Well, forget about them since the timeline tells us that they where just gearing up to the Final War; I doubt anyone there where interested in looking for signals from space.


Right, there's no guarantee that anyone beyond 50 light-years of Earth can detect us. Yes, we've been making noise for 100 years, but attenuation, under the best circumstances, is quadratic over distance. And it's not under the best circumstances because there's a lot of dust in interstellar space. However rarefied it is, we're talking about over a quadrillion kilometres in a straight line.

The Calvin's Hope expedition could not land on the planet. So all they had available were their own on-board transmitters, which are likely not powerful enough to transmit back to Earth or Beowulf. If they had landed, they might have been able to build the infrastructure for a more powerful transmitter which would let them keep in contact with the rest of the human species.

That was not an option in Sanctuary. They arrived with very little runway left in their resources, to a planet that was hidden behind a dust cloud anyway, and they had their second incident not long thereafter.

We also know from Grayson that certain factions didn't want to be found, so they would not be attempting to transmit anyway.



Your are thinking of Radar in which the strength of the return signal is inversely proportional to the distance raised to the Fourth power. The strength of a signal, sent either intentionally or inadvertently, is inversely proportional to distance squared.

Keep in mind that we can send signals to and receive signals from the Voyager spacecraft which IIRC are 100+ AU away and have a puny, 20 Watt transmitter.

In comparison, any plausible drive for a sunlight transport would have PetaWatt or even ExaWatt class power. A radio transmitter or even a laser with Gigawatt class power would probably be as inconsequential as a CB radio is to a semi truck.
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Re: Bolthole location
Post by ThinksMarkedly   » Wed Nov 06, 2019 8:33 pm

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TFLYTSNBN wrote:Your are thinking of Radar in which the strength of the return signal is inversely proportional to the distance raised to the Fourth power. The strength of a signal, sent either intentionally or inadvertently, is inversely proportional to distance squared.


In a prefect vacuum, sure. The problem is that the ISM is not a perfect vacuum, there's a lot of dust in it, especially in the plane of the Milky Way. We don't know how far off the plane Sanctuary is, but everything in Honorverse seems to be within 25 light-years of it or so. The absorption of signals cause extinction.

See the Wikipedia article on ISM and Light extinction.

Keep in mind that we can send signals to and receive signals from the Voyager spacecraft which IIRC are 100+ AU away and have a puny, 20 Watt transmitter.

In comparison, any plausible drive for a sunlight transport would have PetaWatt or even ExaWatt class power. A radio transmitter or even a laser with Gigawatt class power would probably be as inconsequential as a CB radio is to a semi truck.


200 light-years is 12.7 million AU, 5 orders of magnitude more. That means any signal, by that alone, would be 10^10 times fainter. That is, a 200 GW transmitter would be received on Earth at the same power level as Voyager is today. Which we need the entire Deep Space Array today to receive and we can only do so because there's no other noise to saturate our receivers.

You're right that a photon sail riding a solar-powered laser or a photon drive would be several orders of magnitude more, but it doesn't seem to be what Calvin's Hope used, at least not for the second journey: remember, they only sped up to 0.1c.

So the Calvin expedition could not and would not contact Earth:
  1. They didn't have a terawatt- or petawatt-range transmitter at hand
  2. Their technology was wiped out before they could build one
  3. Even if they had, there's a good chance that the signal would be drowned by other signals arriving at the receiver, from interplanetary and interstellar sources
  4. It probably requires a direction signal-amplification array, so if it's not pointed at the right direction, nothing is going to be received
  5. Finally, even if a signal could have been sent, any help would be 600 years away (for all they knew)
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Re: Bolthole location
Post by TFLYTSNBN   » Thu Nov 07, 2019 3:35 pm

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ThinksMarkedly wrote:
TFLYTSNBN wrote:Your are thinking of Radar in which the strength of the return signal is inversely proportional to the distance raised to the Fourth power. The strength of a signal, sent either intentionally or inadvertently, is inversely proportional to distance squared.


In a prefect vacuum, sure. The problem is that the ISM is not a perfect vacuum, there's a lot of dust in it, especially in the plane of the Milky Way. We don't know how far off the plane Sanctuary is, but everything in Honorverse seems to be within 25 light-years of it or so. The absorption of signals cause extinction.

See the Wikipedia article on ISM and Light extinction.

Keep in mind that we can send signals to and receive signals from the Voyager spacecraft which IIRC are 100+ AU away and have a puny, 20 Watt transmitter.

In comparison, any plausible drive for a sunlight transport would have PetaWatt or even ExaWatt class power. A radio transmitter or even a laser with Gigawatt class power would probably be as inconsequential as a CB radio is to a semi truck.


200 light-years is 12.7 million AU, 5 orders of magnitude more. That means any signal, by that alone, would be 10^10 times fainter. That is, a 200 GW transmitter would be received on Earth at the same power level as Voyager is today. Which we need the entire Deep Space Array today to receive and we can only do so because there's no other noise to saturate our receivers.

You're right that a photon sail riding a solar-powered laser or a photon drive would be several orders of magnitude more, but it doesn't seem to be what Calvin's Hope used, at least not for the second journey: remember, they only sped up to 0.1c.

So the Calvin expedition could not and would not contact Earth:
  1. They didn't have a terawatt- or petawatt-range transmitter at hand
  2. Their technology was wiped out before they could build one
  3. Even if they had, there's a good chance that the signal would be drowned by other signals arriving at the receiver, from interplanetary and interstellar sources
  4. It probably requires a direction signal-amplification array, so if it's not pointed at the right direction, nothing is going to be received
  5. Finally, even if a signal could have been sent, any help would be 600 years away (for all they knew)


You are making good points. However; the signal strength is proportional to the diameter of the emitter antenae squared as well as the diameter of the receiving antenae squared. The Voyager probes have antenae that are only a few meters in diameter. Honorverse starships would have antenae (probably phased array antenae) may be a hundred of meters in diameter during transit and could be dispersed into an array hundreds of kilometers in diameter when they reach their destination. An optical wavelength, phased array, communication laser could have an effective emitter diameter of 100 meters. A few Gigawatts power would be easily detectable at 100s of Lightyears.

The fusion rockets used by sunlight starships would be detectable at hundreds of light years. Keep in mind that the power output for a million ton colony ship would be comparable to the insolation of a habitable planet. The same space based telescopes that would detect and evaluate planets for potential colonization would be able to observe and track the colony ship not only during initial boost but during decelleration.

You might recall that there was once an unappreciated genius known as "NAMELESSFLY" who posted on this board years ago who pointed out that Honor's ambushing of the Havenite ships by sneaking up on them using fusion rockets rather than Impeller drive required a rather absurd obtuseness by the victims. I am informed that David Weber himself was so impressed that he sent a PM to this NAMELESSFLY asking for details of the calculations including the mass ratio (fuel portion) of the ships doing the ambushing.
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Re: Bolthole location
Post by ThinksMarkedly   » Thu Nov 07, 2019 7:19 pm

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TFLYTSNBN wrote:The fusion rockets used by sunlight starships would be detectable at hundreds of light years. Keep in mind that the power output for a million ton colony ship would be comparable to the insolation of a habitable planet. The same space based telescopes that would detect and evaluate planets for potential colonization would be able to observe and track the colony ship not only during initial boost but during decelleration.


When the ship is accelerating away from Earth, sure, it would be a bright source of light, close by, and directly pointed at you. When it's decelerating 200 light-years away, it's pointed directly away from you. The thermal bloom of the rocket may not be visible.

As for the second journey, it's not pointed at Earth but neither is it pointed directly away. So the thermal bloom may be observable, but it's much, much fainter.

Another point is that there's a very, very bright source of light at the exact direction you need to be looking at: the star.

You might recall that there was once an unappreciated genius known as "NAMELESSFLY" who posted on this board years ago who pointed out that Honor's ambushing of the Havenite ships by sneaking up on them using fusion rockets rather than Impeller drive required a rather absurd obtuseness by the victims. I am informed that David Weber himself was so impressed that he sent a PM to this NAMELESSFLY asking for details of the calculations including the mass ratio (fuel portion) of the ships doing the ambushing.


Let's not discuss The Battle That Shall Not Be Named... perpetual motion devices abound.
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Re: Bolthole location
Post by Robert_A_Woodward   » Fri Nov 08, 2019 1:24 am

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(I snipped out the rest of the original and kept this reference to the Cerberus action)

TFLYTSNBN wrote:
You might recall that there was once an unappreciated genius known as "NAMELESSFLY" who posted on this board years ago who pointed out that Honor's ambushing of the Havenite ships by sneaking up on them using fusion rockets rather than Impeller drive required a rather absurd obtuseness by the victims. I am informed that David Weber himself was so impressed that he sent a PM to this NAMELESSFLY asking for details of the calculations including the mass ratio (fuel portion) of the ships doing the ambushing.


I wonder how much of that was cribbed from my comments from September 1998:

"Half an hour under thrusters and not detected? How is the gas accelerated? If the thrust is coming from thermal expansion, the exhaust of those rockets should be a plasma hot enough to radiate X-rays in order to get that much delta-V. It will then, eventually, cool down enough to radiate in infrared and radio. If accelerated by some sort of mass driver, then the gas will not be hot, but would still be a very fast moving plume that would interact (noisily in radio) with the interplanetary plasma. In chapter 29 of In Enemy Hands, Shannon, at tens of millions of miles away, was able to see that the "Tepes" had lost air and pieces of its hull. An cruiser squadron under reaction thrusters should be more obvious (even at hundreds of million of miles)."
----------------------------
Beowulf was bad.
(first sentence of Chapter VI of _Space Viking_ by H. Beam Piper)
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Re: Bolthole location
Post by tlb   » Fri Nov 08, 2019 8:22 am

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TFLYTSNBN wrote:You might recall that there was once an unappreciated genius known as "NAMELESSFLY" who posted on this board years ago who pointed out that Honor's ambushing of the Havenite ships by sneaking up on them using fusion rockets rather than Impeller drive required a rather absurd obtuseness by the victims. I am informed that David Weber himself was so impressed that he sent a PM to this NAMELESSFLY asking for details of the calculations including the mass ratio (fuel portion) of the ships doing the ambushing.

Robert_A_Woodward wrote:(I snipped out the rest of the original and kept this reference to the Cerberus action)

I wonder how much of that was cribbed from my comments from September 1998:

"Half an hour under thrusters and not detected? How is the gas accelerated? If the thrust is coming from thermal expansion, the exhaust of those rockets should be a plasma hot enough to radiate X-rays in order to get that much delta-V. It will then, eventually, cool down enough to radiate in infrared and radio. If accelerated by some sort of mass driver, then the gas will not be hot, but would still be a very fast moving plume that would interact (noisily in radio) with the interplanetary plasma. In chapter 29 of In Enemy Hands, Shannon, at tens of millions of miles away, was able to see that the "Tepes" had lost air and pieces of its hull. An cruiser squadron under reaction thrusters should be more obvious (even at hundreds of million of miles)."

Congratulations to you both, but the explanation provided at the time is still sufficient to explain why Honor's force was not detected:
1. The standard, expected method to detect another ship is to look for a wedge. That is only now being upset with the spider drive.
2. The SLN force was approaching a vast minefield that was expected to be under enemy control. A clear danger concentrates the mind.
3. Honor was attacking in line with a star. A cursory glance her way would see what was expected, since there was no thought that ships could have been captured.

Note that latter Honor admits that this was a tactic of desperation and a more vigilant enemy would have discovered her.
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