How Can Astronauts Tell How Fast They’re Going?

Weirdly, spaceships have no direct way to gauge their own speed. Luckily, we can use some physics tricks to figure it out.
eLife

Distinct allosteric remodeling of HIV-1 Env dynamics on virions by gp41-directed antibodies reveals two modes of neutralization

HIV-1 envelope glycoprotein (Env), a gp120–gp41 trimer, undergoes coordinated conformational changes that drive membrane fusion and allow immune evasion by transiently concealing ...