Distance is one of the important variables that explain volume of trade. Theoretically, distance has negative relationship with trade.

Include distance as one of the variables.

Log(Distance) enters the gravity model as explanatory variable in addition to other relational variables (e.g. social proximity, direct train connection) and so-called mass variables (GDP) for both countries. Distance is calculated upfront.

Which theory of Gravity is right?

Einstein theory of Gravity or Ferent Quantum Gravity (FQG)?

In Einstein theory of Gravity, how you learned from your professors Dark Matter is ‘invisible’ and ‘transparent’ Matter.

In Ferent Quantum Gravity, Dark Matter is not ‘invisible’, is not ‘transparent’ Matter.

https://www.researchgate.net/publication/330832633_Dark_Matter_is_not_'invisible'_is_not_'transparent'_Matter

Distance is one of the important variables that explain volume of trade. Theoretically, distance has negative relationship with trade.

Include distance as one of the variables.