A Mercurial Circumnavigation


A Mercurial Circumnavigation

I've been inspired by several of the recent planetary circumnavigations, particularly Straha's Meridian circumnavigation that was complete with historical lessons about navigation, and how that tied back into the circumnavigation expedition. So I want to try a small circumnavigation myself, and do something similar, but with my own spin on it. To that end, I'll have some brief historical/scientific context that ties into the theme. I apologize if anyone else has covered the same material, but I don't recall seeing it recently, so I think I'm OK.

I'm playing in VR, which I know for some people would be impossible to do with the SRV for long periods of time. Thankfully I don't suffer from those forms of motion sickness, but we'll see how it goes! :D

I have 4x SRVs aboard the Astronomia Nova, so I'm covered in case I blow up one or two along the way. I can also switch off just to have different paint jobs, or different COVAS voices to keep me company.

Planetary selection

Note that I'm not driving on Mercury in the Sol system. This expedition is named in the more general sense, of being quick and whimsical, but also a Mercury-like planet.

First, the planet needed to be small, because I know myself, and half way around the planet I'll probably be hating myself and questioning my life choices. ;) As the primary criteria, I looked up planets with my name on them in the EDSM data, sorted by radius, and found some suitable candidates.

Secondly, the planet needed to be in a tight inner orbit. Like Mercury in our own solar system, I wanted an innermost planet that rapidly progresses through its orbit, for reasons I'll explain in more detail later. Unlike Mercury, the planet I've chosen is incredibly close to its star, and has a "year" of only 1.5 days.

Additionally, it needed to be tidally locked, so that the position of the sun is always an indicator of my progress.

Plus, it needed to be one that I've tagged myself, because I'm a tag snob. I admit it. ;)

While the planet I've chosen is not the smallest, nor the tightest orbit of the planets I've discovered, it has a nice blend of these two features. It's not a pretty planet, nor does it have any particularly remarkable features. But it fits the context of what I'm trying to do. With a radius of 217 km, the circumference (assuming a perfect sphere, which it certainly won't be), will be about 1364 km. It's tiny, but I may try a larger planet again later, depending on how this goes. For now, it's a good step. It also has the added benefit of having Polonium, which has always been a thorn in my side, so hopefully I'll be able to pick some up along the way.

The plan

I intend to start on the day/night terminator, and drive through the daylight side of the planet first, following the equator. This means that the expedition will both start and end with the rising sun. That is, it won't be rising due to the planet's rotation, since it's tidally locked, but rather due to my driving distance. I'll start out driving toward the sun on the horizon, and it will slowly rise for the first 25% of the journey, and then slowly set behind me. The second half of the drive will be on the night side. As the sun starts to appear from beneath the horizon in front of me again, I'll know that I'm almost done. Being so close to the star, with such a tiny orbit, the sun will loom large overhead, while on the day side. And with the short orbital period, "years" will go by as I circumnavigate, meaning that the celestial sphere overhead will be constantly changing.

And the celestial sphere is exactly where my historical/scientific discussion will begin. From there, we'll look at planetary motion and historical solar system models, and eventually come full circle about why the planet Mercury is interesting in this historical context.

As of this writing, I just sold my remaining data at Medusa's Rock in the Crescent Nebula, and have less than an hour's flight to get to the chosen planet and begin.


Planetary Details

Planet:Smojeia LI-E c14-1 1
Type:Metal-rich body (Landable)
Distance to arrival:11 ls
Earth masses:0.0001
Radius:217 km
Surface temperature:1,092 K
Gravity:0.06 G
Orbital period:1.5 d
Rotational period:1.5 d (Tidally Locked)
Approximate circumference:1363.45 km


 
They say, that what I do requires patience of a saint.. I think that planetary circumnavigation is way more absorbing..

good luck Commander.. you will need a lot of it.. and tones of patience


P.S. This is what we do when there is not enough content.. we create it.. even if just with our crazy ideas of personal narration
 
Thanks! Yeah, it's going to be an interesting time. I just haven't decided if that's "interesting" as in "cool", or "interesting" like the (apocryphal) Chinese curse of "may you live in interesting times". :D


I made it to my starting point, at 0 x 71 (roughly). This is very close to the prograde orbit line. From here, I'll be following a heading of mostly 90 degrees. This points slightly to the left of the sun at the moment, due to the planet's axial tilt.

I landed, took some screenshots, and parked for the night. The journey will begin probably tomorrow or Sunday.





And starting stats:

 
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Gah, I am 21,000 ly away! Now that I have found my geysers here, I may just put my great raw mat hunt on hold and come over to visit :D

Good luck, and I am looking forward to seeing what you come up with here!
 

Ian Phillips

Volunteer Moderator
I'm doing my circumnaviagtion using VR too.

At the start I was worried about motion sickness but I haven't experienced any problems really. I've been through some very rough terrain and frequently spin out or end up bouncing down ice walls, upside down, with the view on red-out.

Good luck!
 
Thanks everyone! :) I'm sure some visitors will be quite welcome.

I'll post a real update later, but for now, I've completed the first leg of the journey. I covered slightly over 26 degrees along the equator, and parked up for the night at 0 x 97.24. The sun is already quite noticeably higher in the sky.

 





The Celestial Sphere

The term celestial sphere refers to what you see in the sky, and the relative apparent positions of astronomical objects. All objects in the sky can be imagined as though they are projected on the inside of a giant sphere. In gaming terms, you might think of this as the "sky box", but it's a useful tool in astronomy.

Since astronomical objects are extremely distant, for practical purposes (such as constructing star maps of the sky) they can be thought of as infinitely distant, with parallel sight lines from the ground. This imaginary, projected sphere would be infinitely large, with Earth at its center. While this isn't physically real, astronomers still use a set of two-dimensional coordinates to describe an object's position in the sky, namely Right Ascension and declination, and still use the term "celestial sphere" to describe this coordinate system. For a full three-dimensional description of an object's position in space relative to our solar system, a distance is also needed, but historically this has been the most difficult coordinate to measure. The 2D location within the sky, however, can be measured with great precision, and historically this has been possible for centuries.

In ancient times, there was a widespread belief that these astronomical objects were literally placed on a sphere that surrounded the Earth. There was also a belief that the planets, whose motion in the sky didn't match the more distant objects, might be objects on large, concentric, nested crystal spheres that rotate around the Earth. Planetary motion defied understanding for quite some time, as their movement in the sky often contained strange loops and squiggles, with "retrograde" movement.

As we continue, we'll look at the history of orbital mechanics, and the advances made by various astronomers and philosophers, from geocentric to heliocentric models of the solar system, leading to the present day.




-------------------------------------------

Tonight's progress:

I found a crashed SRV. Amusingly, the only cargo I was interested in was the Bootleg Liquor. I don't have any cargo space on the ship, so I had to ditch it before docking for the night, but I found it amusing to carry that around for a while.





I found my first (and only, so far) Polonium:



A crashed fighter:



Another crashed fighter:



And one of these things:



And stopped here for the night:

 
Thanks everyone! :) I'm sure some visitors will be quite welcome.

I'll post a real update later, but for now, I've completed the first leg of the journey. I covered slightly over 26 degrees along the equator, and parked up for the night at 0 x 97.24. The sun is already quite noticeably higher in the sky.
At this rate, I'm going to have to Buckyball it over there to catch you before you are done!
 
Yeah, this is off to the west of the bubble, past the Crescent Nebula, roughly 7.5 kly from Sol if I recall. It's also in the neighborhood of Cygnus X-1. If you haven't been to Cygnus X-1 before, it might be worth visiting there too, just for historical reasons. It was an important system in determining the existence of stellar remnant black holes. It's in system V1357 Cygni.

EDIT: I certainly picked a desolate little rock of a planet. No real craters, mountains, or canyons to speak of. Just lots of red dirt as far as the eye can see. The good news is that there are some relatively flat areas, and with the low gravity I can "fly" over the terrain for long stretches.
 
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Awesome, one of us, one of us! :D

I wouldn't presume to claim I started this trend but, for those interested, I am documenting and bringing all these planetary circumnavigations togther in one place.



I'll add yours to the OP and will follow your progress with interest. There are currently two other circumnavigations currently in progress, both in the Sol system.

Ian Phillips is currently circumnavigating Charon over here: https://forums.frontier.co.uk/showthread.php/448919-Charon-Circumnavigation

And Jonas Treesong is currently circumnavigating Ariel over here: https://forums.frontier.co.uk/showthread.php/449465-Ariel-circumnavigation
 

Day 2! I completed another 26 degrees, ending at 0 x 123.67. This puts me about 52.5 degrees beyond my starting point, so not quite 1/6 of the way. The sun looks like it will soon be directly overhead. Since I started with it slightly above the horizon, I suspect it will be high noon by the time I've travelled about 75 degrees.



Since this thread is getting image heavy, I'm going to put a lot of it in spoiler tags.

This planet has very few large features, as I noted earlier, but the mountains and craters do exist. They're just very sparsely located. I saw some mountains in the distance to the north, with a darker volcanic look to them, and decided to divert up to them. This took me 3.7 degrees north of the equator. While I didn't climb to the highest peak, I stopped to take in the view at one that gave a wide field of view of the equatorial region I was moving through. Afterward I maintained a heading of roughly 120, until reaching the equatorial line again. I might have gotten a little further had I not diverted briefly, but it was worth the effort.

In the distance, making the decision to go:



Looking over the area that I would have travelled through, had I not diverted:



And the path ahead:





And I passed more peaks as I worked my way through this desolate dark volcanic-looking region:


I found more wreckage:




And I stopped a few times to check my surroundings:
The mountains followed my north side for quite a while, and then slowly receded behind me:





Leaving a dark region, into a sea of brighter reds, and some orange-yellow:


And some of the terrain features that I passed along the way:

A sea of orange, that I didn't know was there until I came over the rise:



In the distance, a crater that I couldn't see until I climbed this hill. I had already passed it:



And a crater directly in my path:


The path ahead, for the next leg:

 
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Aristotle & Ptolemy

For most of human history, it was believed that Earth was the center of the universe. Everything in the sky seemed to rotate around us, in a giant celestial sphere. This view of the cosmos continued well after it was understood that the Earth is spherical, rather than a flat surface.

For instance, Aristotle, who is often considered the "father of science", believed in a geocentric system. His view of a stationary Earth at the center of a revolving universe persisted for well over a thousand years.

Several centuries later, Ptolemy created one of the first models of the solar system that seemed to explain the strange retrograde motion that planets would occasionally have in the sky. He claimed to have based his geometric model on writings from other astronomers spanning over 800 years before him, such as the writings of Hipparchus, who described the motion of the moon using the concept of an Epicycle to explain its variations in speed during its orbit. While epicycles were first proposed by Apollonius of Perga, Ptolemy formalized it and extended the use of epicycles to explain planetary motion, both in terms of speed variations, and the anomolous retrograde loops and squiggles that the planets would draw out against the background stars.

The epicycle (literally "circle moving on another circle") explained these motions by having the planets revolve on circles (or crystal spheres), that in turn would orbit the Earth in circular paths. While this model was able to predict the motion of the planets, it still lacked precision. Nevertheless, this system presisted as the dominant model for centuries, well into the medieval period. It had been a long held belief, that was further perpetuated by Christian Europe, that everything in the heavens should be perfect, and there was nothing more perfect than a true circle, and therefore the orbits must have been perfect circles.

(As an interesting aside-- Ptolemy attempted to calculate the size of the universe, using his epicycle planetary model. He estimated that the Sun was at an average distance of 1,210 Earth radii, and the radius of the celestial sphere was 20,000 times the Earth's radius).





 

Aristotle & Ptolemy

For most of human history, it was believed that Earth was the center of the universe. Everything in the sky seemed to rotate around us, in a giant celestial sphere. This view of the cosmos continued well after it was understood that the Earth is spherical, rather than a flat surface.

For instance, Aristotle, who is often considered the "father of science", believed in a geocentric system. His view of a stationary Earth at the center of a revolving universe persisted for well over a thousand years.

Several centuries later, Ptolemy created one of the first models of the solar system that seemed to explain the strange retrograde motion that planets would occasionally have in the sky. He claimed to have based his geometric model on writings from other astronomers spanning over 800 years before him, such as the writings of Hipparchus, who described the motion of the moon using the concept of an Epicycle to explain its variations in speed during its orbit. While epicycles were first proposed by Apollonius of Perga, Ptolemy formalized it and extended the use of epicycles to explain planetary motion, both in terms of speed variations, and the anomolous retrograde loops and squiggles that the planets would draw out against the background stars.

The epicycle (literally "circle moving on another circle") explained these motions by having the planets revolve on circles (or crystal spheres), that in turn would orbit the Earth in circular paths. While this model was able to predict the motion of the planets, it still lacked precision. Nevertheless, this system presisted as the dominant model for centuries, well into the medieval period. It had been a long held belief, that was further perpetuated by Christian Europe, that everything in the heavens should be perfect, and there was nothing more perfect than a true circle, and therefore the orbits must have been perfect circles.

(As an interesting aside-- Ptolemy attempted to calculate the size of the universe, using his epicycle planetary model. He estimated that the Sun was at an average distance of 1,210 Earth radii, and the radius of the celestial sphere was 20,000 times the Earth's radius).





And that was the kicker with Hipparchus...he had the math right, and actually saw a heliocentric model, but just flat out refused to believe it :D
 
I'm trying to plot a route to this planet from the bubble and it keeps failing at about 75%
I don't remember there being any locked off regions that way.
I'm in a 25ly Cobra III, are there any big jumps needed?

I'm going to plot a shorter route and sort it when I get to the waypoint.

Edit: EDSM can plot a route so I'm happier now.
Hope I get there before you finish!
 
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