Discussion Overview
The discussion revolves around the conversion of velocity units from kilometers per second (km/s) to kiloparsecs per giga year (kpc/Gyr). Participants explore the appropriate conversion factors and the definitions of a Gyr, while also addressing the precision of astronomical measurements related to distance.
Discussion Character
- Technical explanation, Debate/contested, Conceptual clarification
Main Points Raised
- One participant questions the conversion factor of 0.964275 and seeks a precise definition of a Gyr, noting that different definitions may exist.
- Another participant provides a conversion factor of 1.02268944 for converting km/s to kpc/Gyr, assuming Gyr refers to a giga year (10^9 years).
- A further reply suggests that astronomers use the Julian year for such conversions, leading to a slightly different conversion factor of 1.02271128.
- Concerns are raised about the precision of the conversion between parsecs and kilometers, with one participant noting that the astronomical unit (AU) varies by about 2%, which could affect the accuracy of the parsec definition.
- Another participant clarifies that the AU does not vary and explains its scientific definition, asserting that the parsec's accuracy is tied to the AU's definition.
- One participant acknowledges a misunderstanding regarding the definition of the parsec, indicating a need for clarification on the topic.
Areas of Agreement / Disagreement
Participants express differing views on the conversion factors and the definitions of Gyr and AU. There is no consensus on the precise conversion factor or the implications of the AU's definition on the parsec's accuracy.
Contextual Notes
Unresolved issues include the exact definitions of a Gyr and the implications of the AU's variability on the conversion between kilometers and parsecs. The discussion reflects ongoing uncertainty regarding these definitions and their impact on calculations.