Guide to the Cosmos

 Making the Wonders of our Universe Accessible to Everyone

We’re Finally Here, But Where’s Pluto?

& Release of Feynman Simplified 2A, 2B


On July 14, 2015, New Horizons took this image of Pluto that awed the world.



The success of the mission to Pluto was greeted with much well-deserved publicity. But one fascinating aspect of this story received scant attention. This $700 million mission was literally a shot in the dark that was saved by old-school astronomy.


Remarkably, when New Horizons was launched in January 2006, Pluto’s orbit was known with a precision of only 0.002%, which seems fine, but isn’t nearly good enough.


NASA has been so successful in so many missions that everyone assumes they know where they’re going. The Mars Curiosity Rover, for example, landed within 1.5 miles of its target.


But Pluto is very different; it takes 248 years to loop around the Sun. Since Clyde Tombaugh discovered it in 1930, Pluto has completed only 1/3 of an orbit. It hasn’t been where it is now since 1767, six years before the Boston Tea Party.


Adding to the drama, New Horizons takes wonderful pictures, but does no image analysis — it’s strictly point-and-shoot. Scientists at Mission Control must tell New Horizons where to point and when to shoot.


Modern high-precision observations of Pluto began fairly recently. Extrapolating this data to the flyby date left Pluto’s location uncertain by 62,000 miles. New Horizon’s aim could have been off by 44 Pluto diameters.


Flying at 32,000 mph, New Horizons moves one Pluto diameter in under 3 minutes. That’s a time window of 0.000,06% in a 9.5-year mission.


Realizing Pluto’s orbital uncertainty could well be catastrophic, navigation team leader Dr. Marc Buie, perhaps echoing Jim Lovell on Apollo 13, said simply: “We have a problem.”


Exploration is all about conquering the unknown and overcoming uncertainty. If everyone in 1969 knew how to land on the Moon and return safely, everyone would have done it. Only NASA did.


So how did the New Horizons team overcome this problem?


Six years after launch, Buie visited the Lowell Observatory where Tombaugh discovered Pluto. Tombaugh’s images were too blurry, but Buie happened to find archived photographs taken by Carl Lampland over a 20-year period ending in the 1950’s. For reasons that had nothing to do with Pluto, Lampland took 1000 pictures of the same piece of sky. By sheer luck, Pluto just happened to be there.


Using the best current technology, Buie meticulously digitized 1000 very old photographs, and calculated Pluto’s orbit with unprecedented precision — and just in time.


After it passed Pluto, New Horizons turned and took this image of Pluto eclipsing the Sun.


This shows Pluto’s atmosphere is over 100 miles thick, much larger than scientists had guessed.




I am happy to announce the newest releases in the Everyone's Guide to the Feynman Lectures series:


Feynman Simplified 2A and 2B cover half of the greatest lectures ever given on electromagnetism by the physicist who knew it best. While preserving Feynman’s profound insights and understanding, Feynman Simplified makes this scientific treasure accessible to mere mortals.





The topics we explore include:

  • Maxwell’s Equations of Electromagnetism
  • Algebra & Calculus of Vector Fields
  • Gauss’ & Stokes’ Theorems
  • Electrostatics with Conductors & Dielectrics
  • Electrostatic Energy
  • Electricity in the Atmosphere
  • Why The Same Equations Appear Throughout Physics
  • Magnetostatics
  • Dynamic Electric & Magnetic Fields
  • Filters & Transmission Lines
  • Electromagnetic Waves in Vacuum
  • Electrical Circuits & Components
  • Circuit & Cavity Resonance



Best Regards,



July, 2015


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