Staying under sun for 9 months straight

[exander]

TL;DR Summary

I am working on a story and would like helping figure out how a person can stay under sun for 9 months straight

Hello,

I am working on a story and I need to figure out how my protagonist can stay consecutively without sun setting over the horizon for at least 9 months.

My idea is to start at the North Pole:
1) Experience continuous daylight from March Equinox to September Equinox.
2) Before the September Equinox, arrive at the South Pole to experience continuous daylight from September Equinox to December Solstice.
3) Stay under sun during the whole time.

Most likely person can't stay exactly in the South or North Pole, so probably the closest city/station. So this would need to match.
I assume the transfer from the North Pole to the South Pole has to be quick, maybe spiraling around the planet to stay under the sun?

Can you offer ideas, calculation, how to best achieve this?

 

[DaveC426913]

Your protag doesn't need to stay directly at the poles. The sun stays above the horizon for long periods of time at latitudes much less than 90 degrees.

How is your protag getting around? Foot? Car? Boat? Plane? Each will have an effect on the path he can take. By plane, for example, he can theoretically travel to the antipodes in a half day of sunlight.

 

[exander]

Your protag doesn't need to stay directly at the poles. The sun stays above the horizon for long periods of time at latitudes much less than 90 degrees.

How is your protag getting around? Foot? Car? Boat? Plane? Each will have an effect on the path he can take. By plane, for example, he can theoretically travel to the antipodes in a half day of sunlight.

I know, but the further the poles, the shorted the times. He would most likely stayed the further north he could get and normally live there.

The question is what is the least technology he can get it, I will use it to set the Epoch. Currently, I don't have even hypothesis how to do it without a plane. And the question is how fast the plane needs to be. Or is there another way?

 

[Halc]

A train could get you from north to south, but it requires a track that nowhere exists.
So airplane it is.

Put your guy in high orbit. Problem solved.
Put him on the moon. He could then stay in the light even at the equator with a recreational vehicle, or if he's exceptionally athletic, a bicycle would do. But if he's close to a pole, walking is enough, and he doesn't even need to switch poles for the lunar winter.

 

[exander]

I actually thought about going to orbit, that pushes the story to be too futuristic. Lowest possible technology would be preferable. So it seems to be plane.

Could a ship theoretically do it as well?

 

[DaveC426913]

Put him on the moon. He could then stay in the light even at the equator with a recreational vehicle, or if he's

I think it was Joe Haldeman who wrote a story I've never forgotten. It was a about a crewpeson who got left behind on the Moon. The next ship was a month away. In order to stay alive she had to stay on the sunlit side of the Moon. So she had to hump it. That's 11,000km of hopping in 600 hours.

 

[DaveC426913]

Could a ship theoretically do it as well?

Probably not but it's hard to say.

Does the protag have control over when the ordeal occurs? eg. Can they choose optimial locations and time of year to their benefit? I'm sort of imagining it's essentially a bet - like Around the World in 80 Days.

The reason this is germane is because the protag will probably have to do the very same calculations we'e going to end up doing right here, before they can decide of it's even feasible enough to make the claim.

I'm starting with the assumption that we know they get from 90N to 90S in 12 hours - which requires a speed of 1,040mph. But can we do it any slower? (to make for better story).

If I could see this as an animation, that might give a clue:

Alternately, I'm toying with breaking the problem down to as simple a schematic as possible and using only geometry. But it's still a 3 dimensional problem: 2 space dimensions and one time dimension.

 

[exander]

Probably not but it's hard to say.

Does the protag have control over when the ordeal occurs? eg. Can they choose optimial locations and time of year to their benefit? I'm sort of imagining it's essentially a bet - like Around the World in 80 Days.

The reason this is germane is because the protag will probably have to do the very same calculations we'e going to end up doing right here, before they can decide of it's even feasible enough to make the claim.

I'm starting with the assumption that it is possible to thread a path through both space and time that is slower than the obvious 'get from 90N to 90S in 12 hours'.

If I could see this as an animation, that might give a clue:
View attachment 351901

Protag cannot change the start, but We can assume that he is already in the north during the polar day for at least a month. He can plan when he leaves to make it to the south.

The task can be simplified: protag is in polar day in the north and has to move into polar day in the south without the sun setting behind the horizon for him. How many months he spends in the north and in the south are actually not important. The question is how to make it between these two regions.

I could imagine sailing west from the north, We can take Norway as the point of origin for example. I would assume 18, maybe even 20 hours is there to make it (maybe even longer coming between north and South America), because he is moving west (like Around the World in 80 Days).

 

[Baluncore]

And the question is how fast the plane needs to be.

Simple and uneconomic, without optimisation. The circumference of the arctic circle is; sin(23.5°) = 40% of the equator. You could travel east to west along the arctic circle, at 664 km/h in a plane.

 

[DaveC426913]

I could imagine sailing west from the north, We can take Norway as the point of origin for example. I would assume 18, maybe even 20 hours is there to make it (maybe even longer coming between north and South America), because he is moving west (like Around the World in 80 Days).

The problem is that any path that is not due north-south results in a greater distance to travel, which means they have to go that much faster - which pushes up your minimum allowable speed/technology - not much but a little.

 

[exander]

Simple and uneconomic, without optimisation. The circumference of the arctic circle is 40% of the equator. You could travel east to west along the arctic circle, at 664 km/h in a plane.

But, you would need to do the whole at least 3 months? Because once polar day is over there then you need to circle or sun sets behind the horizon. Moving to the South Pole seems the only option to me.

 

[DaveC426913]

Simple and uneconomic, without optimisation. The circumference of the arctic circle is; sin(23.5°) = 40% of the equator. You could travel east to west along the arctic circle, at 664 km/h in a plane.

Wait. Isn't it a requirement that they start near one pole and end up near the other?

I mean, if they can just stay in the northern hemisphere, they could do it pretty easily, no? They wouldn't even need a jet.

 

[exander]

Wait. Isn't it a requirement that they start near one pole and end up near the other?

I mean, if they can just stay in the northern hemisphere, they could do it pretty easily, no? They wouldn't even need a jet.

No, no requirement. I just don't have other idea. You have idea how to stay 90 days under sun only on north hemisphere?

 

[Baluncore]

Moving to the South Pole seems the only option to me.

If you must make one move only, it should be done pole to pole over the equinox.

Due N-S, in a 12 hour day, requires 20,000 km in 24 hours = 833.4 km/hour.

 

[DaveC426913]

Man,

Due N-S, in a 12 hour day, requires 20,000 km in 24 hours = 833.4 km/hour.

Doesn't it have to happen in 12 hours, not 24? That's how I got 1040mph(1675km/h).

 

[DaveC426913]

I'm trying to imagine a path that stays in the northern hemisphere, but does less than rotational speed of the Earth - per Baluncore's post #9.

Man it's hard to wrap my head around sunlight on a rotating body. Is there away to make an easier model?

 

[Baluncore]

Deosnt it have to happen in 12 hours, not 24? That's how I got 1040mph.

My error, 20 Mm / 12 hr = 1667 km/h.

 

[Baluncore]

I'm tring to imagine a path that stays in the northern hemisphere, but does less than rotational speed of the Earth.

That is a permanent flight along the arctic circle in winter.

 

[DaveC426913]

That is a permanent flight along the arctic circle in winter.

As you mentioned in post 9, yes. I just can't come to terms with that being the best (i.e. slowest ) he can do.

 

[Baluncore]

Start at the arctic circle, fly in a spiral for 45 days, at an ever decreasing speed, until you stop at the N-pole on the day of the vernal equinox. Wait 6 months for the autumnal equinox, then spiral out to the arctic circle in 45 days. That gives nine months of continuous sunlight in the Northern Hemisphere.

 

[DaveC426913]

Start at the arctic circle, fly in a spiral for 45 days, at an ever decreasing speed, until you stop at the N-pole on the day of the vernal equinox. Wait 6 months for the autumnal equinox, then spiral out to the arctic circle in 45 days. That gives nine months of continuous sunlight in the Northern Hemisphere.

OK, that still requires a speed of 664km/h for at least some portion of the journey, yes? So that still sets the same lower bound on the technology required.

A pity it makes for a too simple plot vehicle.

 

[Halc]

The problem is that any path that is not due north-south results in a greater distance to travel, which means they have to go that much faster - which pushes up your minimum allowable speed/technology - not much but a little.

Slower, not faster. Yes, the path is longer, but the diagonal (more like the shape of an integral sign) trip between poles buys many more hours to add to the 12, at a cost of only a little more distance.

We presume the guy isn't able to keep a plane in the air for 45 day, even though the tech to do so hypothetically exists. Yea, they can refuel in air, but can any engine really run that long?

No, finding the most efficient route between poles is what's needed. Can we keep the trip subsonic? The problem isn't one of calculus. It can be done with simple algebra.
I withdraw that. It's a calculus thing.