How would lack of stars , sundials , and compasses affect the exploration age?

Question

In my fictitious universe, a god like entity ( which is an amalgam of all individuals , scientific understanding , capabilities , and tech of a type 3.5 civilization ) produces a sun with the same mass of our own , and a habitable Dyson sphere around it ( ground level being 1 AU from the sun )

In this Dyson World , their are no stars ( naturally ) to be used to glean ones direction , and there is no main magnetosphere , only local ones for every few hundred miles , and on top of that , due to the geometry of the sphere , and inconsistent day and night cycles , sun dials are impossible.

My question is : how might these factors adversely affect exploration of the sphere?

Answer 1

It will be a land without night as large distant features on the Dyson sphere if they exist will play the role of local constellations

Well, let's start by making it clear just how large the world is. Given how big space is, 1 AU might not sound like a lot, given how far Pluto is (40 AU) or the nearest next star (15,000 AU).

Nonetheless, 1AU is a big number for us humans. 149,598,000 km. Going on a highway at 130 km/h, it would take you 130 years to cover that distance. As you can imagine, a Dyson sphere with that radius would be quite large. We can plug $r=149598000$ km into the area of a sphere formula, given by the simple formula:

$$4\pi r^2$$

That gives an area of 281,229,865,302,746,000 square km. Earth's area (oceans and all) is 510,070,000 sq. km. So your Dyson sphere is 551,353,270 times bigger than the earth in terms of surface. If you took all 7 billion people on Earth and spread them evenly across this world, there would one person per about as much land as all of Asia.

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Now, assuming you somehow keep an Earth-like atmosphere, due to air diffraction, things turn blue and blurry in the distance, so even though the world goes on at a negligible angle for what seems like forever, you're only able to see a few hundred km even at the best possible visibility if you look in a direction parallel to the ground. You can always look up (only 30 km of air to look through or so), but more on that later.

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Even assuming there are no internal planets to the Dyson (but why not - throw a Venus control center in there), there are still ways of figuring out where you are.

The easiest way is to start from the Imperial palace and build roads. Every 1km, you place a 1 km marker. You can then establish two roads, or, absent straight roads two preferred directions, at 90 angles to each other for simplicity.

The Forbidden Palace Road and the Sublime Porte Road at at 90 degree angles. All other roads are marked in reference to them in the empire. The silk road marker 5943 indicates that the location is at 4832 FP and 1832 SP, near the far borders of the Empire.

Alongside rivers you would have similar markers, letting you know your relative position compared to the Capital in the same fashion as the road markers.

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Sea travel will be only marginally harder, especially if you wish to lose sight of land. Markers and lighthouses can be established for coastal travel. Large semi-distant large scale geographical feaures (visible through the outside the atmosphere so not subject to air distortion) would serve a similar role as constellations during the day-time. Night time travel would be tough, especially if nights last a long time. Perhaps people would seek port during the evenings?

EDIT: Actually, it's an interesting question of how would the Dyson sphere look across. Obviously continent-sized features will be visible to the naked eye only at something like 100 times the Earth-Moon distance. 1 degree on the Dyson is about 2,610,977 km, so about 7 times the Earth-moon distance. 10 degrees, or about a fist above the horizon, would be about 1/2 of the minimum Earth-Mars distance, so it's a safe bet continent-sized features will not be resolvable by the naked eye. However, it's pretty clear that inner-shell-induced "nights" would not be very dark, due to all the reflected light from the more distant sides of the dyson...

So the answer will depend of the high-level granularity (isotropy) of the world. Are there mega-features, like uncrossable seas the size of Saturn with nary a trace of land, or are we talking a patchwork of seas and lands roughly Earth-like in its distribution?

Answer 2

For all intents and purposes people will feel as if they are wandering in a nearly infinite world, so exploration is going to be tricky anyway. Imagine that two civilizations might emerge a relatively short distance away from one another (relative to the size of the sphere), but they might not meet until their technology level matches our own in the modern age.

It's going to wreak havoc on trade, and it might mean that anyone brave enough to travel a few hundred (OK, maybe thousand) miles may never find their way back to their family again.

However, the situation is not exactly hopeless. One way for people to navigate (in a relatively low-tech civilization) will be to build massive towers that you can locate with binoculars, and travel towards.

Later these can be replaced with balloon beacons, radio beacons, etc. Eventually a GPS network of sorts (the GPS devices would have to be land based, as these guys will never have space ships) can be set up.