Re: The Astronomy Thread
Posted: Fri Jun 25, 2021 1:42 am
The suggestion was that the Loroi explorers found a lot of dead worlds in the direction of Earth and stopped looking in that direction.
Depending on costs - maybe even something unmanned could do
In some frequencies, but not others. If I recall correctly, the gas giants are also "louder" than either the sun or the Earth in some frequencies as well. It's related to the way that charge particles from the sun interact with planetary ionospheres, but it's been a very long time since I read that literature. Suffice to say, amplitude of RF emissions alone are not sufficient to reveal the existence of intelligent life. Loud but very regular emissions probably indicate natural phenomenon like pulsars. The frequency matters as well, since some are more likely than others to be used by intelligent life. So the best bet to find Earth from RF emissions would be to search for irregular transmissions in the watering hole. Since Loroi planets presumably have a significant amount of atmospheric water, that would be a natural frequency band for the Union and Hierarchy to search as well, if only to look for more Loroi splinter colonies. Who knows, a search in that band might be how they found the Pipolsid.
Yes, I contend that all major powers would be aware that the planet exists, as well as it's mass and orbit. A while back, there was discussion related to page 107 that concluded that the Loroi would likely be able to pinpoint which planet is Earth given only the rough direction and orbital period.Other species might have been aware of the existence of Earth without necessarily knowing about humanity, especially if they observed our world before the 1900s.
Old photons would probably be your best way of deciding where to send those survey vessels. It would be prohibitively expensive to send a ship to each system especially considering the need to refuel and resupply. You'd want to chose the targets from the systems with planets that most resemble what you're looking for. In the Loroi's case, they'd want atmospheric oxygen and water, as well as suitable gravity and surface temperatures, all things that we are able to detect on exoplanets with current technology. Given the incentives to establish new colonies, locate other splinter colonies, and locate and identify other intelligent species, I see no reason why any species would fail to develop more advanced exoplanet detection techniques than we currently possess.
Maybe, but the cost of making observations is so low as to be a rounding error in a modern nation's budget. Where was this suggestion made?
Range is likely a limiting factor, even for unmanned systems. Fuel in Outsider is neither free nor limitless.
It can be simply obscured by the shine of several brighter stars when observed from Loroi territory - not even totally, just enough to make it a bother to look into, and thus push it down the list of interest of the Union astrographers.
Due to the nature of FTL travel in Outsider, the expense is there as a matter of fact. A vessel needs to jump from system to system in order to reach a high-lighted star for closer scrutiny.Gudo wrote: ↑Fri Jun 25, 2021 1:57 amOld photons would probably be your best way of deciding where to send those survey vessels. It would be prohibitively expensive to send a ship to each system especially considering the need to refuel and resupply. You'd want to chose the targets from the systems with planets that most resemble what you're looking for. In the Loroi's case, they'd want atmospheric oxygen and water, as well as suitable gravity and surface temperatures, all things that we are able to detect on exoplanets with current technology. Given the incentives to establish new colonies, locate other splinter colonies, and locate and identify other intelligent species, I see no reason why any species would fail to develop more advanced exoplanet detection techniques than we currently possess.
That makes way more sense.
We've already used a number of techniques to locate exoplanets, many don't relay on the transit of said planet in front of it's star. Looks like the wiki lists 16 methods that have found planets and another 6 that are plausible. It doesn't really matter much in this case I think, since Alexander is simply going to point out the star and planet for them. I assume he'd also give them enough information about the system (number of planets, major moons, etc) that Union astronomers could piece together a fairly accurate map of the system. Still, the Loroi have had access to space based telescopes and vantages from multiple stellar systems for well over 1000 years by now.Unless the plane of the planetary orbits happen to be edge-on and transit the star, I think it would be very hard to deduce the orbits in a large system like Sol by remote observation. The slight wobbles would be pretty hard to pick out amidst the noise of solar activity.
You're 100% correct that you'd get a "free" opportunity to survey each system en-route to a point of interest. But I don't think the Terrans would've been in the habit of visiting absolutely everything, at least not until they contacted the Orgus. Unless a system was en-route to a potentially habitable planet, I can't see the justification for pre-contact Terrans to visit. They only thing an uninhabitable system could provide would be raw resources and there should still be plenty in Terran space. The TCA would probably have plenty of other budgetary priorities and might have a hard time justifying a physical survey unless they could point to a possible colony site and say "This expedition will enable us to colonize this location."GeoModder wrote: ↑Fri Jun 25, 2021 12:48 pmDue to the nature of FTL travel in Outsider, the expense is there as a matter of fact. A vessel needs to jump from system to system in order to reach a high-lighted star for closer scrutiny.... The only thing such an observation program can add is offer possible priority targets.
I wonder how much of the justification for the "physically visit each system" approach is due to the TCA's need for detailed maps for military purposes. It would be interesting to compare the pre and post Orgus contact survey practices.As far as I can discern from the Insider, the Scout Corps surveys each and every star within reach, whether or not some telescopic survey marks this-or-that star as interesting.
The majority of the methods listed are only available in rare, exotic cases, like when the primary is a neutron star, or the primary transits a background star. There are really only three methods that have produced a decent number of planet detections: transit, radial velocity, and direct imaging. But even these three methods only work in specific situations, and none of them maps out a whole system.Gudo wrote: ↑Fri Jun 25, 2021 3:41 pmWe've already used a number of techniques to locate exoplanets, many don't relay on the transit of said planet in front of it's star. Looks like the wiki lists 16 methods that have found planets and another 6 that are plausible.
Why not? In Outsider humanity has had the capability for interstellar travel for almost 3 generations, and still they've only gone as far out as Aldebaran as indicated in the Local Bubble map. And our ensign seems to mark human territory within the region around Arcturus, Vega, and Sirius. There's not too many stars within that area to make it impossible to visit in that timespan. For a fair number of star systems within this region scientific curiosity alone warrant closer scrutiny.Gudo wrote: ↑Fri Jun 25, 2021 3:41 pmYou're 100% correct that you'd get a "free" opportunity to survey each system en-route to a point of interest. But I don't think the Terrans would've been in the habit of visiting absolutely everything, at least not until they contacted the Orgus. Unless a system was en-route to a potentially habitable planet, I can't see the justification for pre-contact Terrans to visit. They only thing an uninhabitable system could provide would be raw resources and there should still be plenty in Terran space. The TCA would probably have plenty of other budgetary priorities and might have a hard time justifying a physical survey unless they could point to a possible colony site and say "This expedition will enable us to colonize this location."GeoModder wrote: ↑Fri Jun 25, 2021 12:48 pmDue to the nature of FTL travel in Outsider, the expense is there as a matter of fact. A vessel needs to jump from system to system in order to reach a high-lighted star for closer scrutiny.... The only thing such an observation program can add is offer possible priority targets.
GeoModder wrote: ↑Fri Jun 25, 2021 10:21 pmWhy not? In Outsider humanity has had the capability for interstellar travel for almost 3 generations, and still they've only gone as far out as Aldebaran as indicated in the Local Bubble map. And our ensign seems to mark human territory within the region around Arcturus, Vega, and Sirius. There's not too many stars within that area to make it impossible to visit in that timespan. For a fair number of star systems within this region scientific curiosity alone warrant closer scrutiny.Gudo wrote: ↑Fri Jun 25, 2021 3:41 pmYou're 100% correct that you'd get a "free" opportunity to survey each system en-route to a point of interest. But I don't think the Terrans would've been in the habit of visiting absolutely everything, at least not until they contacted the Orgus. Unless a system was en-route to a potentially habitable planet, I can't see the justification for pre-contact Terrans to visit. They only thing an uninhabitable system could provide would be raw resources and there should still be plenty in Terran space. The TCA would probably have plenty of other budgetary priorities and might have a hard time justifying a physical survey unless they could point to a possible colony site and say "This expedition will enable us to colonize this location."GeoModder wrote: ↑Fri Jun 25, 2021 12:48 pmDue to the nature of FTL travel in Outsider, the expense is there as a matter of fact. A vessel needs to jump from system to system in order to reach a high-lighted star for closer scrutiny.... The only thing such an observation program can add is offer possible priority targets.
Valid criticism, but my point was more to the effect that we've only been seriously searching for two decades and we've already developed a number of techniques. At a higher tech level, I'm sure we'll develop more which may have potential. A grand unified theory or a better understanding of dark matter or dark energy might unlock quite a few doors. Who knows, maybe gravitational wave observatories like LIGO could be useful (if the lasers, mirrors, and detectors were put on asteroids or orbital platforms, such an observatory could be made truly massive with only a minimal investment in actual material.)Arioch wrote: ↑Fri Jun 25, 2021 9:34 pmThe majority of the methods listed are only available in rare, exotic cases, like when the primary is a neutron star, or the primary transits a background star. There are really only three methods that have produced a decent number of planet detections: transit, radial velocity, and direct imaging. But even these three methods only work in specific situations, and none of them maps out a whole system.
That's good to know, I was having a hard time figuring out what planes things were in relative to each other.Transit has been the most successful, but it can only be used on a tiny fraction of stars... Union space is well above the Sun's ecliptic plane, so they will not observe any transits...
The Loroi alone have (had the ability to make) over a millennium and a half of observations, and from multiple systems. Intelligence sharing agreements are surely part of Union membership, so there's also observations by the Neridi, Barsam, Pipolsid, and all the rest that can be consolidated. Comparing many observations, taken over multiple centuries and from multiple vantage points, could cut down a significant amount of noise. Presumably both the Union and Hierarchy have conducted a program of comparing observations made by their various member spices, if only to give some Pipolsid PhD student something to do.Radial velocity is really the only method Union observers could use to remotely map the Sol system... In theory, sufficiently precise spectrum measurements can reveal an entire planetary system, but noise from stellar activity puts a maximum limit on how accurate those measurements can be, and you have to observe the system for several complete orbital cycles, which take hundreds of years.
It should also tell you the distance from the star. But like I said in an earlier post, it's likely the Union does not have much more information than that, as otherwise the planet would be too interesting.And even when successful, the detection only tells you the mass and orbital period of the planet; nothing about its diameter or composition.
I feel like this is getting a little out of the astronomy lane and more into theoretical economics of a fictional nation. I don't think we have a way of gauging if going out "only" as far as Aldebaran represents an ambitious scouting program, or a conservative one. We don't really have a good way of considering the costs, especially the opportunity costs of the program. I think we can all agree: the ability to send survey ships (autonomous or not) reduces the need for, and therefore value of, especially advanced exoplanet detection techniques; there's no reason to not use both survey ships and observatories in tandem; and astronomical observations can be used to guide a survey program.GeoModder wrote: ↑Fri Jun 25, 2021 10:21 pmWhy not? In Outsider humanity has had the capability for interstellar travel for almost 3 generations, and still they've only gone as far out as Aldebaran as indicated in the Local Bubble map. And our ensign seems to mark human territory within the region around Arcturus, Vega, and Sirius. There's not too many stars within that area to make it impossible to visit in that timespan. For a fair number of star systems within this region scientific curiosity alone warrant closer scrutiny.
During the Age of Sail in Europe, there was almost always some war between the European naval powers going on (France, England, Spain, the United Provinces,...). That didn't stop trade or discovery travels to be made to all possible corners of the Earth.spacewhale wrote: ↑Sat Jun 26, 2021 6:44 pmConsider nations on Earth that had the technological capability to potentially explore the rest of the planet for centuries, but due to various political reasons they did not, like Zheng He and the treasure fleet. With a series of wars with your immediate neighbors, I can't imagine there was much drive to sail across the galactic Pacific to find Earthlings.
I was only taking the amount of time in account. 70+ years of interstellar capability. At most several hundred stars within say a 10 parsecs radius.Gudo wrote: ↑Sat Jun 26, 2021 4:28 pmI feel like this is getting a little out of the astronomy lane and more into theoretical economics of a fictional nation. I don't think we have a way of gauging if going out "only" as far as Aldebaran represents an ambitious scouting program, or a conservative one. We don't really have a good way of considering the costs, especially the opportunity costs of the program. I think we can all agree: the ability to send survey ships (autonomous or not) reduces the need for, and therefore value of, especially advanced exoplanet detection techniques; there's no reason to not use both survey ships and observatories in tandem; and astronomical observations can be used to guide a survey program.GeoModder wrote: ↑Fri Jun 25, 2021 10:21 pmWhy not? In Outsider humanity has had the capability for interstellar travel for almost 3 generations, and still they've only gone as far out as Aldebaran as indicated in the Local Bubble map. And our ensign seems to mark human territory within the region around Arcturus, Vega, and Sirius. There's not too many stars within that area to make it impossible to visit in that timespan. For a fair number of star systems within this region scientific curiosity alone warrant closer scrutiny.
Sure, but I'm just pointing out that Zheng He's voyages could have easily done the same, they didn't. Just because you *can* do something doesn't mean you will do something.
Problem is that you can't go very far with this method because there's only so much hyperfuel your ship can carry. So you need to be able to refuel at some point, and when you're going through a patch of useless empty systems, at some point you cannot go further beyond without organizing the hyperspace equivalent of the Black Buck Raid.
You said it yourself.