home / medterms medical dictionary a-z list / ethmoid sinus definition Medical Definition of Ethmoid sinus Ethmoid sinus: A collection of air cells within the ethmoid bone, a spongy bone which makes up the front of the floor of the skull and the roof of the nose. From the Greek ethmos, sieve + eidos, resemblance = like a sieve.
Confidence votes 84.8K. It takes 4.05 hours to 4.12 hours for light from the sun to reach Neptune, depending where it is in it's orbit. It takes 4.05 hours to 4.12 hours for light from the sun to reach Neptune, depending where it is in it's orbit.
Neptune, the most distant planet, takes 4.16 hours for light to reach. The nearest star, Proxima Centauri, takes light 4.3 years to get to. The fastest spacecraft ever launched from Earth is NASA's New Horizons mission, which will make a close encounter with Pluto and its moons in 2015.