On Earth, the cardinal directions are straightforward. The arrow on a compass points to the nearest magnetic pole. You can then use it to travel anywhere on Earth.
In space, the idea of anything being “central” enough to be used as a “North” (since the universe has no center) or being fixated enough to not somehow pose issues is more convoluted.
If you were a pioneer of space exploration, what would your “North” be?
The Emperor’s psychic beacon, of course.
The Astronomican.
The Emperor Protects.
I thought this was obvious
Probably arbitrarily one of the two vectors perpendicular to the plane of the Milky Way? (Assuming it wasn’t necessary for this navigation system to work outside of our galaxy.)
intergalactic
planetary, planetary, intergalactic
But seriously, even so, I think it’d be reasonable to still have per-galaxy navigation systems.
We could assign it to any point within a recognizable region in the Cosmic Microwave Background, which would probably be the most universally-applicable reference available. One just needs to be able to filter out the noise from surrounding celestial bodies. The CMB does slowly change over time, but so too does the position of stars within galaxies and galaxies relative to one another.
Cosmic background radiation provides a stable frame of reference for setting up a coordinate system. If the explorers have a main HQ base, it can be set as the origin (0,0,0). The location of an object in space can be communicated using a tuple like (10km, 30°, 30°), representing the radius (distance to the object), polar angle (angle between the positive z-axis and the line connecting the origin to the point), and azimuthal angle (angle between the positive x-axis and the line connecting the origin to the point on the xy-plane).
Alternatively, if only a general region is needed, grid coordinates can be used with any useful unit of measurement for the distance between grid lines.
Yep. Fun fact, if you used the center of the Earth at Epoch 0, the reference point would shoot out of central Africa a few seconds later in the direction of Ophiuchus.
Source: Napkin math that was surprisingly hard, because of all the moving parts with their own coordinate systems that don’t necessarily have nice conversion tables in common use.
If we’re talking intergalactic navigation, I’d use QSO J0529-4351 as north.
It has the highest chance of being visible from wherever we want to go.
I was going to suggest the Great Attractor or the Shapley Supercluster, but I think your suggestion is better. It’s more point-like and since it’s farther away (well outside of the reachable universe) it results in a more uniform set of directions over long distances.
Of course, cultural influence will be big. If these explorers are Terragen then most likely the Milky Way’s north/south direction will be pretty deeply ingrained in their coordinate systems. They might keep on using that, since it’s not like manual astrolabe-style navigation will ever be relevant at that level of technology.
Center of gravity of the galactic cluster/supercluster
Works very well until you’re moving between superclusters, at which point the universe becomes homogeneous (as far as is known). At that point you probably just need to set an arbitrary origin for your system of location.
So your momma?
We already have one. Its Mecca, and all the aliens are Muslim.
(putting my shitposts with the other shitposts so they don’t bother)
It will be so much more complicated than "North" IMO.
We will use something like XNAV. It becomes a measure of time as much as any measure of location, along with a measure of relative gravity.
I don’t think space exploration in the current culturally adolescent fantasy of a naval voyage type of experience will ever happen. I believe we will traverse the stars, but it will be long after most of humanity lives in O’Neill cylinder like space habits, primarily in cislunar space. The big shift will come after we have effective infrastructure to access the vast resource wealth, first in near Earth objects, then in other small bodies such as Ceres if it is fully solidified, or other planetesimal cores that are accessible. Gravitational differentiation of heavy elements sequesters almost all of Earth’s resources. We are fighting over the scraps of a billion years or so of smaller collisions on the skin of Earth that happened to remain accessible, and did not get subducted by plate tectonics or buried too deeply to access. Undifferentiated bodies from the early stellar formation should be much more abundant in mineral wealth, and a planetesimal core, should absolutely dwarf most mineral wealth humans have ever scavenged.
Once we get to this stage, I don’t think we will leave until Sol starts causing problems that harken a coming distant end to Sol. At that point, I believe we will build a massive infrastructure to produce antimatter in quantity and generation ships for one way travel.
In that scenario, navigation in a human sense is largely irrelevant. When we are interstellar travelers, the destination will be our guiding star. I believe we will likely also create something like kilometers scale self replicating systems for resource acquisition and processing. These will need to navigate within a stellar system. For those use cases, maybe they would use something like XNAV as a backup, but they would likely use two way communications beacons with something like an all talk and listen all the time type of management. I think this kind of communication will likely be critical for all human colonies as well to ensure cultural unity. I don’t think we will ever travel the stars. Space is far too vast. I think FTL or even a substantial percentage of it is pure fantasy. One of our biggest issues with the concept is that we call it FTL. Light is not relevant here, it is just a shortcut term that is not relevant to the real issue of the Speed of Causality. Light can travel at the SoC, but the SoC has no inherent need for or relationship to light as a fundamental property. If no photons are present the SoC marches on.
I view the present sci-fi navel drama trope like the naïveté of 15th century Europeans saying “We’ll just sail around the world backwards for a new trade route to India.” Reality is far more complicated and beyond the scope of anything these leaders imagined possible. …but that is my $2 comment when you only asked for $0.02. I really like the subject of futurism, and like to expand upon the abstracted ideas. I’m certainly no expert. This is part of a creative writing hobby project and I’m always open to adding complexity or changes with new information.
I think FTL or even a substantial percentage of it is pure fantasy.
I used to think FTL was nonsense, but it turns out the universe has a built-in mechanism for time travel at the Planck scale. Particles smaller than the atom swing both ways when it comes to causality and retrocausality.
Now I think that either FTL is completely impossible at the macro scale or it’ll be so easy we’ll be embarrassed we didn’t have it sooner.
I’d use Discworld nomenclature:
- Hubward
- Rimward
- Turnwise
- Widdershins
Fun fact, woddershins is a real word, it used to be used for talking about someone walking around a church counter clockwise, which would make it possible for a demon (or fae?) to snatch children up
What about catywampus?
A few problems with this. That requires a world experienced in 2D, with one axis being towards or away from the centre, and the other being clockwise or anticlockwise. Works great when discussing intragalactic travel, but OP specified intergalactic travel. Where there is neither an obvious centre point nor a single plane on which things predominantly occur.
Though fwiw, language very similar to that is legitimately used in some real world languages. Some Malayo-Polynesian languages, such as Manam, talk about direction in terms of seaward, inland, clockwise, and anticlockwise.
You can prefix the coordinates with the name of the current nearest star or center of galaxy.
Universal coordinates are fairly useless anyway, given how everything moves around in space.
Also up and down, I assume?
You would likely start from the center of your galaxy, then pick a culturally relevant star near the outskirts, in our case Sol, and call that, well, something (Solbound?) Then work your right angles from there. You could pick other cultural stars in the other directions too.
Most galaxies are pretty flat, so you’d probably have to reference a conveniently positioned other galaxy for your up and down.
Earth, obviously. Or rather, where we think we left it…
By the time intergalactic navigation is relevant we’ll have likely dismantled Earth. The vast majority of it is just sitting there generating gravity, a huge waste of its potential.
I don’t think it really makes sense to have a north as such. The only potentially exception I can think of is more of a definition of ‘up’ rather than north and pertains to hemispheres of bodies.
Earth-bound cardinals are basically 2 dimensional vectors. Not really helpful in intergalactic space.
So i guess what your asking is what is the stationary point of reference that you use to calculate your position? You can use any object but typically you use whatever object your gravitationally bound to. Like in earth orbit you use earth, in interplanetary space you use the sun, in interstellar space it becomes more up to you. Center of galaxy maybe, or nearest star. Kinda depends what ur trying to do.
