#1 physicist

#1 is Aquarius Galileo Galilei, physics began as a science from Galileo's main laws. Main discoveries:

* Created the first telescope and discovered Moon, explored the Milky way

* Correctly claimed that planets rotate around the Sun 

* Discovered the laws of inertia, free fall, oscillation period constant

* Created microscope and thermoscope

Among the top 5 are James Maxwell Gemini and Niels Bor Libra in the Guardian ranking. All rankings show Maxwell and Niels Bor in the top 5. The top 5 contain 3 air signs (Aquarius, Libra, Gemini). 

I also found Aquarius Amper in the top 6 inventions 

Aquarius Alessandro Volta (electricity voltage was named after him) was among great scientists 

Enrico Fermi Libra was among the top 5 in Google Hits Study (2009), in some rankings Aquarius Josiah Gibbs is among 10. See different rankings

#1 element is air (Aquarius, Libra, Gemini) and #1 physicist is Aquarius

Among the living physicists, #1 is Capricorn: Stephen Hawking

Isaak Newton was Capricorn. After Aquarius, I would put second Capricorn.