# Neil Ashby

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**Neil Ashby** (born March 5, 1934, in [Dalhart, Texas](/source/Dalhart,_Texas)) is an American physicist. He attended Dalhart High School, graduating in 1951.[1] He received his B.A. degree (summa cum laude) in physics from the [University of Colorado](/source/University_of_Colorado), [Boulder](/source/Boulder,_Colorado), in 1955, and the M.S. and Ph.D. degrees from [Harvard University](/source/Harvard_University), [Cambridge, Massachusetts](/source/Cambridge,_Massachusetts) in 1956 and 1961, respectively. After spending a year in Europe as a postdoctoral fellow, he joined the faculty of the department of physics at the University of Colorado in 1962. He has been a professor of physics there since 1970, and was department chair from 1984 to 1988. He is currently [professor emeritus](/source/Professor_emeritus) – theoretical math-physics at the University of Colorado.[2]

He consults for the Time and Frequency Division of the [National Institute of Standards and Technology](/source/National_Institute_of_Standards_and_Technology), working on relativistic effects on clocks and global time synchronization. His work was the basis of general relativistic correction being properly included in the [Global Positioning System](/source/Global_Positioning_System). He was a member of the International Committee on General Relativity and Gravitation from 1989 to 1995. He serves on several international working groups on relativistic effects in [geodesy](/source/Geodesy) and in [metrology](/source/Metrology). His work has influenced areas as diverse as:

- [Introduction to general relativity](/source/Introduction_to_general_relativity)
- [General relativity](/source/General_relativity)
- [Time dilation](/source/Time_dilation)
- [Earth-centered inertial](/source/Earth-centered_inertial) co-ordinates
- [Primary Atomic Reference Clock in Space](/source/Primary_Atomic_Reference_Clock_in_Space)
- [Sagnac effect](/source/Sagnac_effect)
- [Einstein synchronisation](/source/Einstein_synchronisation)

## Selected publications

- "Canonical Planetary Perturbation Equations for Velocity-Dependent Forces, and the Lense-Thirring Precession," N. Ashby, T. Allison,[3]
- "Relativistic Gravity Theory And Related Tests With A Mercury Orbiter Mission" [4] N. Ashby, P.L. Bender, I. Ciufolini, L. Iess, Proceedings of the Symposium on Future Fundamental Physics Missions in Space and Enabling Technologies, 5–7 April 1994, El Escorial, Spain (Eds. J. Leon And J. Perez-Mercader, Instituto Nacional de Tecnica Aeroespacial, Madrid.)
- "Relativity in the Future of Engineering,"[5] N. Ashby, IEEE Transactions on Instrumentation and Measurement 43, 505-514 (1994).
- "Introduction to Relativistic Effects in the Global Positioning System,"[6] N. Ashby, J.J. Spilker, Jr., Ch. 18 in The Global Positioning System—Theory and Application, Eds B.W. Parkinson, J.J. Spilker, Jr., American Institute of Aeronautics and Astronautics, (1995).

## References

1. ["Neil Ashby | Class of 1951"](http://www.classmates.com/people/Neil-Ashby/319023301)

1. ["Ashby, Neil"](https://web.archive.org/web/20160303224249/http://phys.colorado.edu/people/ashby-neil). Archived from [the original](http://phys.colorado.edu/people/ashby-neil) on 2016-03-03.

1. ["Canonical planetary perturbation equations for velocity-dependent forces, and the Lense-Thirring precession"](https://www.researchgate.net/publication/226300407)

1. Turyshev, Slava G; Anderson, John D; Hellings, Ronald W (1996). "Relativistic Gravity Theory And Related Tests With A Mercury Orbiter Mission". [arXiv:gr-qc/9606028](https://arxiv.org/abs/gr-qc/9606028)

1. Ashby, N. (August 1994). "Relativity in the future of engineering". *IEEE Transactions on Instrumentation and Measurement*. **43** (4): 505–514. [Bibcode:1994ITIM...43..505A](https://ui.adsabs.harvard.edu/abs/1994ITIM...43..505A). [doi:10.1109/19.310159](https://doi.org/10.1109/19.310159)

1. [Introduction to Relativistic Effects in the Global Positioning System](http://aapt.org/doorway/TGRU/articles/Ashbyarticle.pdf)

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