Conventional images of the Earth and the moon place them close together, the moon hovering, seemingly, right over our planet's shoulder. Of course, this isn't accurate; we know just from looking at ...

A proposed five-satellite Cosmic Positioning System could measure cosmic distances directly and help address discrepancies in the Hubble constant through solar system–scale triangulation.

Illustration comparing the planets of the Solar System and the Sun on the same scale. The planets are shown to scale relative to each other but their distances are not. From left to right the bodies ...