THE DISCOVERY OF NEPTUNE

Ben Brown & Leo McElroy

URANUS’ ORBIT: MODEL VS. DATA Mathematical Model

Newtonian mechanics Elliptical orbits

Observed Orbit Mainly elliptical Significant deviations or “wobbles”

Competing Explanations: The current model was wrong There was another planet pulling Uranus out of

orbit

VERRIER AND ADAMS Urbain Le Verrier and John Couch Adam both

believed there was another planet September 23rd, 1845: Neptune was first

observed using Verrier’s predictions Neptune’s orbit and mass predicted using the wobbles

in Uranus’ orbit.

WHY DOESN’T URANUS GET PULLED OUT OF ORBIT?

STRUCTURAL REALISM

5

Commitment to Underlying Mathematical Structure

Verrier and Adams prediction was ultimately observable. What if it wasn’t?

IMAGE SOURCES A treatise on astronomy, descriptive, physical

and practical: designed for schools, colleges, and private students - Horatio Nelson Robinson

http://upload.wikimedia.org/wikipedia/commons/thumb/0/01/Gravitational_perturbation.svg/2000px-Gravitational_perturbation.svg.png