It was so cool reading the work of high schoolers who tested out dark matter and machine learning astronomical classifications for themselves. JEI always needs more reviewers (I think I was/am the only astronomy reviewer); check it out: emerginginvestigators.org!

I think it says something that the "project's" prized fellowship went to a computer scientist. Although I try not to judge people for what postdoc they have to take nowadays.

Now if the eccentricity is greater than (1-q)/(1+q) where q is the mass ratio, the orbits are no longer nested, they form figure 8-like orbits with their ellipses rotated 180 degrees from each other. In this case, and only this case, does it make sense to say they both orbit each other. Rant over.

What does influence the geometry is the mass ratio and the eccentricity. In the barycentric frame, Pluto's apocenter is closer to the barycenter than Charon's pericenter. The orbits are nested, and we can easily say Charon orbits Pluto, and Pluto does not orbit Charon (and they both orbit the COM).

The barycenter’s position doesn’t change the geometry of the system; it’s just any systems center of mass. Inherent in the inside/outside central body definition is the central bodies density/radius something that has next to 0 to do with the orbital dynamics.

Once you have these it's easy to draw sillier reference frames like alpha Centauri A centric-frame or even better the Charon-centric frame.

There's a weird obsession with the barycenter being inside or outside the central body in astro-interested communities. I try to highlight here how the center of mass's location doesn't have an impact on the orbital configuration. The important quantity is actually the eccentricity.

Scary how often “I do my own research” means “I am the research subject”

Wait! It smells very strongly of garlic! No stealing internet: who wants to write an April’s fools article about K2-18b keeping vampires away.

What how why

@astrojake.bsky.social your favorite molecule

Great discussion here, just wanted to pipe in that one thing people miss in Liu Cixin's presentation of the DF is the "technological explosion" axiom. That the timescale and degree of a civilization's technological advancement is completely unknowable. In 3BP universe, any prey may become a predator