Here is the proposal for the Lake Tahoe Bet written by MCToon.

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Lake Tahoe Earth Shape Challenge v0.5
2026-01-06

Preface:
The shape of the Earth has been a subject of debate, with some claiming the Earth is flat while others maintain it is a globe.  One way to test the shape of the Earth is to observe whether objects at a distance are visible or hidden by the Earth's curvature.

If the Earth is a globe, objects beyond a certain distance will be hidden below the horizon due to the curvature of the Earth.  The distance at which an object becomes hidden depends on the height of the observer, the height of the target object, the curvature of the Earth, and atmospheric conditions.

If the Earth is flat, objects should remain visible regardless of distance, limited only by atmospheric blockages such water droplets, smoke, etc., the resolving power of the observation equipment, and the brightness of the target.

Lake Tahoe provides an ideal location for such a test.  The distance between the south dock and the north shore on opposite sides of the lake is at least 19.5 miles.  At this distance, if the Earth is a globe, a target object positioned at a low height above the water surface should be hidden below the horizon due to Earth's curvature.  If the Earth is flat, the same target should remain visible.

This challenge is structured as a bilateral bet between two parties: one party representing the flat Earth position and one party representing the globe Earth position.  Each party will place $5,000 USD in escrow.  The winner will receive the entire $10,000 USD escrowed amount.


Challenge:
The challenge is to conduct a visual observation test across Lake Tahoe to determine whether a target object can be seen from the South Dock to the North Shore at a distance of at least 19.5 miles.

The specific locations are:
- South Dock (Observer Location): 38.938659° N, 120.039424° W
- North Shore (Target Location): The target may be positioned anywhere on the north shore between coordinates 39.238376° N, 120.041223° W and 39.222366° N, 120.004872° W.  Any docks located within this coordinate range may be used for positioning the target.

Win Conditions:
- If the illuminated target is visible to the observer at the South Dock, the flat Earth position wins the challenge.
- If the illuminated target is not visible to the observer at the South Dock, the globe Earth position wins the challenge.


Test Conditions and Requirements:

1. Timing:
   The test must be conducted at night.  "Night" is defined as the period between civil twilight end and civil twilight begin, as calculated for the specific date and location of the test.  Civil twilight times will be determined using official astronomical calculations for the coordinates of the South Dock on the date of the test.

2. Target Object Specifications:
   a. Location: The target object must be positioned anywhere on the North Shore within the coordinate range specified in the Challenge section.  Any docks located within this coordinate range may be used for positioning the target.  The exact coordinates of the target position must be documented and agreed upon by both parties prior to the test.
   
   b. Height: The highest point of the target object must be no more than 10 feet (3.048 meters) above the water surface of Lake Tahoe.  The exact height must be measured and documented using an accurate measuring device, and verified by both parties or their designated representatives prior to the test.
   
   c. Type and Construction:
      - The target must be a sign (rigid or semi-rigid), banner (flexible material), or similar flat or planar object designed to be clearly identifiable at distance
      - Minimum surface area: 4 square feet (0.372 square meters) when viewed from the observer's perspective
      - Materials: Clearly visible when illuminated (e.g., white or light-colored material, reflective material, or material with high contrast markings)
      - Must not be a trivial geometric shape (such as a single point, line, or minimal object) that could be confused with other light sources or objects
      - Must remain stable and not deform significantly during the test period
   
   d. Identification Features:
      The target must include unique identifying features (text, symbols, patterns, colors, etc.) that allow the observer to confirm they are viewing the correct target object and not another light source or object.  These identifying features must be agreed upon by both parties prior to the test and must be documented.
   
   e. Positioning:
      - The target must be positioned such that its face (the side with identifying features) is oriented toward the South Dock
      - The target must be positioned upright or at an angle that maximizes visibility from the observer location
      - The target must be securely positioned such that it does not move during the test period
      - The target mounting structure (if any) must be included in the height measurement if it extends above the target itself
      
   f. Responsibility: it is the responsibility of the globe proponent to provide the target object.

3. Light Source Specifications:
   a. The target object must be illuminated by a light source that is sufficient to make the target visible clear atmospheric conditions if no obstructions are in the way.
   b. The light source must be operational and turned on during the entire observation period.
   c. The light source must be of sufficient intensity to be visible at the test distance under clear atmospheric conditions if no obstructions are in the way.
   d. The light source may be attached to the target object or positioned separately, but must illuminate the target object in a way that makes it clearly identifiable.
   e. The light source specifications (type, wattage, lumens, color, etc.) must be documented and agreed upon by both parties prior to the test.

4. Observer Location and Equipment:
   a. The observer must be positioned at the South Dock location.
   b. The observer may use any visual observation equipment, including but not limited to: unaided human vision, binoculars, telescopes, night vision equipment, or other optical instruments.
   c. The observer's instrument height above the water surface must be measured and documented.  The observer's instrument height must not exceed 10 feet above the water's surface.
   d. It is the responsibility of the flat proponent to provide the observation equipment.

5. Weather and Atmospheric Conditions:
   a. The test must be conducted under clear weather conditions with no precipitation, fog, or other atmospheric conditions that would prevent observation under normal circumstances.
   b. Visibility must be sufficient that objects at the test distance would be visible if there is an unobstructed straight line path between the observer and the target.
   c. Weather conditions must be documented at the time of the test, including but not limited to: temperature, precipitation, fog, wind, and any other relevant meteorological data.
   d. Both parties must agree that weather conditions are suitable for the test prior to beginning observations.

6. Documentation Requirements:
   Prior to the test, the following must be documented and agreed upon by both parties:
   a. The exact coordinates of the target position on the North Shore (must be within the coordinate range specified in the Challenge section, and may be on any dock within this coordinate range)
   b. Target specifications: type, dimensions, materials, identifying features, and method of mounting or securing
   c. Photographs of the target object from multiple angles
   d. Light source specifications (type, wattage, lumens, color, etc.)
   e. The exact distance from the South Dock to the target position using the Haversine formula
   f. All measurements (target height, observer instrument height, coordinates, etc.) documented with precision instruments and verified by both parties
   g. All equipment used (observation equipment, light sources, measuring devices, etc.) documented with specifications and model numbers where applicable
   
   During and after the test:
   h. The test must be documented with video and/or photographic evidence from both the observer location and the target location.
   i. The test must be witnessed by neutral third parties or documented in a manner that allows independent verification.
   j. All documentation must be made available to both parties and to any arbitrators if arbitration is required.


Escrow:
Each party shall place $5,000 USD in escrow prior to the test.  The total escrowed amount is $10,000 USD.

The escrow agent must be agreed upon by both parties and must be a neutral third party with no financial interest in the outcome of the challenge.

The escrow funds must be deposited and confirmed prior to the test being conducted.  The test may not proceed until both parties have confirmed that the full $10,000 USD is held in escrow.

Upon determination of the winner, the escrow agent shall transfer the entire $10,000 USD to the winning party within 30 days of the official determination.

If the test cannot be completed due to circumstances beyond the control of either party (e.g., natural disaster, government restrictions, etc.), or if the challenge expires without a test being conducted, the escrow funds shall be returned to each party in the amount they deposited ($5,000 USD each), minus any escrow fees.


Judging:
The determination of whether the target is visible or not visible shall be made by the observer at the South Dock during the test.

For the target to be considered visible, the observer must be able to:
- See the illuminated target object
- Identify the specific identifying features of the target as specified in section 2.d (Target Object Specifications - Identification Features)
- Confirm that the observed object is the intended target and not another light source or object

The observer must make a clear determination: either the target is visible (with all identifying features confirmed) or the target is not visible.  The determination must be made during the test period and cannot be changed after the test is concluded.

If the observer determines the target is visible (with identifying features confirmed), the flat Earth position wins.
If the observer determines the target is not visible (or cannot confirm the identifying features), the globe Earth position wins.

The observer's determination is final unless challenged through the arbitration process described below.


Arbitration:
If either party disputes the observer's determination or believes the test was not conducted according to the specifications in this document, they may request arbitration.

Arbitration will be conducted by a panel of three neutral judges selected according to the following process:
1. The party requesting arbitration (the "Requesting Party") selects one judge.
2. The other party (the "Responding Party") selects one judge.
3. The two selected judges together select a third judge.

All judges must be neutral third parties with no financial interest in the outcome and no prior relationship with either party that would create a conflict of interest.

Judge qualifications:
- Judges must have expertise in one or more of the following areas: optical physics, atmospheric science, surveying, navigation, astronomy, or related fields.
- Judges must have at least 5 years of professional experience in their field of expertise.
- Judges must currently be working or teaching in their field of expertise.
- Documentation of credentials is required.

The arbitration panel will review:
- The observer's determination
- All documentation from the test
- Whether the test was conducted according to the specifications in this document
- Any disputes regarding test conditions, equipment, or procedures

The arbitration panel's decision is final and binding on both parties.

The costs of arbitration (including but not limited to judge fees, travel expenses, etc.) shall be paid equally by both parties unless the arbitration panel determines that one party acted in bad faith, in which case that party shall bear all arbitration costs.


Test Scheduling:
Both parties must agree on a specific date and time for the test.  The test must be scheduled at least 30 days in advance to allow for proper preparation, escrow setup, and witness arrangements.

If the parties cannot agree on a test date within 90 days of both parties agreeing to participate in this challenge, either party may withdraw from the challenge and their escrow funds shall be returned, minus any escrow fees.

The test may be rescheduled by mutual agreement of both parties, but must be completed within one year of the initial agreement to participate, unless both parties agree to extend the deadline.


Expiration:
This challenge expires one year after both parties have agreed to participate and have deposited their escrow funds, unless:
- The test is completed and a winner is determined, or
- Both parties agree to extend the deadline, or
- The challenge is terminated by mutual agreement of both parties.


Modifications:
This challenge document may not be modified after both parties have agreed to participate and have deposited their escrow funds, except by written agreement of both parties.

Any modifications must be documented in writing and signed by both parties.  If modifications are made, a new message digest (SHA-256 hash) must be calculated for the modified document to ensure the integrity of the challenge specifications.


Notes:
1. Water Level Considerations:
   Lake Tahoe water levels may vary.  The height measurements (target height and observer instrument height) must be measured relative to the actual water surface at the time of the test, not relative to a fixed reference point.

2. Safety:
   All parties must ensure that the test is conducted safely and in compliance with all applicable laws and regulations.  This includes but is not limited to: boating regulations, lighting regulations, trespassing laws, and any other relevant legal requirements.

3. Message Digest:
   Once this challenge document is finalized and agreed upon by both parties, a SHA-256 message digest should be calculated to ensure the document cannot be modified without detection.  The message digest should be published along with this document.

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