Skip to main content
Log in

Advancing fundamental physics with the Laser Astrometric Test of Relativity

The LATOR mission

  • Original Article
  • Published:
Experimental Astronomy Aims and scope Submit manuscript

Abstract

The Laser Astrometric Test of Relativity (LATOR) is an experiment designed to test the metric nature of gravitation—a fundamental postulate of the Einstein’s general theory of relativity. The key element of LATOR is a geometric redundancy provided by the long-baseline optical interferometry and interplanetary laser ranging. By using a combination of independent time-series of gravitational deflection of light in the immediate proximity to the Sun, along with measurements of the Shapiro time delay on interplanetary scales (to a precision respectively better than 0.1 picoradians and 1 cm), LATOR will significantly improve our knowledge of relativistic gravity and cosmology. The primary mission objective is i) to measure the key post-Newtonian Eddington parameter γ with accuracy of a part in 109. \(\frac{1}{2}(1-\gamma)\) is a direct measure for presence of a new interaction in gravitational theory, and, in its search, LATOR goes a factor 30,000 beyond the present best result, Cassini’s 2003 test. Other mission objectives include: ii) first measurement of gravity’s non-linear effects on light to ∼0.01% accuracy; including both the traditional Eddington β parameter and also the spatial metric’s 2nd order potential contribution (never measured before); iii) direct measurement of the solar quadrupole moment J 2 (currently unavailable) to accuracy of a part in 200 of its expected size of ≃ 10 − 7; iv) direct measurement of the “frame-dragging” effect on light due to the Sun’s rotational gravitomagnetic field, to 0.1% accuracy. LATOR’s primary measurement pushes to unprecedented accuracy the search for cosmologically relevant scalar-tensor theories of gravity by looking for a remnant scalar field in today’s solar system. We discuss the science objectives of the mission, its technology, mission and optical designs, as well as expected performance of this experiment. LATOR will lead to very robust advances in the tests of fundamental physics: this mission could discover a violation or extension of general relativity and/or reveal the presence of an additional long range interaction in the physical law. There are no analogs to LATOR; it is unique and is a natural culmination of solar system gravity experiments.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Fig. 1
Fig. 2
Fig. 3
Fig. 4
Fig. 5
Fig. 6
Fig. 7

Similar content being viewed by others

References

  1. Anderson, J.D., Williams, J.G.: Long-range tests of the equivalence principle. Class. Quantum Gravity 18, 2447 (2001)

    Article  MATH  ADS  Google Scholar 

  2. Anderson, J.D., Lau, E.L., Turyshev, S.G., Williams, J.G., Nieto, M.M.: Recent results for solar-system tests of general relativity. BAAS 34, 833 (2002)

    Google Scholar 

  3. Bean, R., Carroll, S.M., Trodden, M.: Insights into dark energy: interplay between theory and observation (2005). astro-ph/0510059

  4. Bennett, C.L., Halpern, M., Hinshaw, G., Jarosik, N., Kogut, A., Limon, M., Meyer, S.S., Page, L., Spergel, D.N., Tucker, G.S., Wollack, E., Wright, E.L., Barnes, C., Greason, M.R., Hill, R.S., Komatsu, E., Nolta, M.R., Odegard, N., Peirs, H.V., Verde, L., Weiland, J.L., [i.e. WMAP Science Team]: First year Wilkinson Microwave Anisotropy Probe (WMAP) observations: preliminary maps and basic results. Astrophys. J. Suppl. 148, 1 (2003). astro-ph/0302207

    Article  ADS  Google Scholar 

  5. Bertolami, O., Páramos, J.: The pioneer anomaly in the context of the braneworld scenario. Class. Quantum Gravity 21, 3309 (2004) gr-qc/0310101

    Article  MATH  ADS  Google Scholar 

  6. Bertolami, O., Páramos, J.: Astrophysical constraints on scalar field models. Phys. Rev. D71, 023521 (2004). astro-ph/0408216

    ADS  Google Scholar 

  7. Bertolami, O., Páramos, J., Turyshev, S.G.: General theory of relativity: will it survive the next decade? In: Proc. 359th WE-Heraeus Seminar: Lasers, Clock, and Drag-free: Technologies for Future Exploration in Space and Gravity Tests. University of Bremen, ZARM, Bremen, Germany, 30 May–1 June 2005. “Lasers, Clocks, and Drag-Free: Exploration of Relativistic Gravity in Space.” H. Dittus, C. Laemmerzahl, S. Turyshev, editors. (Springer Verlag, 2006), pp. 27–67 (2006), gr-qc/0602016

  8. Bertotti, B., Iess, L., Tortora, P.: A test of general relativity using radio links with the Cassini spacecraft. Nature 425, 374 (2003)

    Article  ADS  Google Scholar 

  9. de Bernardis, P., Ade, P.A.R., Bock, J.J., Bond, J.R., Borrill, J., Boscaleri, A., Coble, K., Crill, B.P., De Gasperis, G., Farese, P.C., Ferreira, P.G., Ganga, K., Giacometti, M., Hivon, E., Hristov, V.V., Iacoangeli, A., Jaffe, A.H., Lange, A.E., Martinis, L., Masi, S., Mason, P.V., Mauskopf, P.D., Melchiorri, A., Miglio, L., Montroy, T., Netterfield, C.B., Pascale, E., Piacentini, F., Pogosyan, D., Prunet, S., Rao, S., Romeo, G., Ruhl, J.E., Scaramuzzi, F., Sforna, D., Vittorio, N.: A flat universe from high-resolution maps of the cosmic microwave background radiation. Nature 404, 955 (2000)

    Article  ADS  Google Scholar 

  10. Capozziello, S., Troisi, A.: PPN-limit of fourth order gravity inspired by scalar-tensor gravity. Phys. Rev. D72, 044022 (2005). astro-ph/0507545

    MathSciNet  ADS  Google Scholar 

  11. Carroll S.M.: The cosmological constant. Living Rev. Rel. 4, 1 (2001). astro-ph/0004075

    Google Scholar 

  12. Carroll, S.M., Hoffman, M., Trodden, M.: Can the dark energy equation-of-state parameter w be less than − 1? Phys. Rev. D68, 023509 (2003). astro-ph/0301273

    ADS  Google Scholar 

  13. Carroll, S.M., Duvvuri, V., Trodden, M., Turner, M.: Is cosmic speed-up due to new gravitational physics? Phys. Rev. D70, 043528 (2004). astro-ph/0306438

    ADS  Google Scholar 

  14. Carroll, S.M., De Felice, A., Duvvuri, V., Easson, D.A., Trodden, M., Turner M.S.: The cosmology of generalized modified gravity models (2005). astro-ph/0410031

  15. Carroll, S.M.: Is our universe natural? (2005). hep-th/0512148

  16. Damour, T., Nordtvedt, K.L., Jr.: General relativity as a cosmological attractor of tensor scalar theories. Phys. Rev. Lett. 70, 2217 (1993)

    Article  ADS  Google Scholar 

  17. Damour, T., Nordtvedt, K.L., Jr.: Tensor-scalar cosmological models and their relaxation toward general relativity. Phys. Rev. D48, 3436 (1993)

    MathSciNet  ADS  Google Scholar 

  18. Damour, T., Polyakov, A.M.: String theory and gravity. Gen. Relativ. Gravit. 26, 1171 (1994)

    Article  MathSciNet  ADS  Google Scholar 

  19. Damour, T., Polyakov, A.M.: The string dilaton and a least coupling principle. Nucl. Phys. B423, 532 (1994)

    Article  MathSciNet  ADS  Google Scholar 

  20. Damour, T., Esposito-Farese, G.: Testing gravity to second post-Newtonian order: a field-theory approach. Phys. Rev. D53, 5541 (1996a). gr-qc/9506063

    MathSciNet  ADS  Google Scholar 

  21. Damour, T., Esposito-Farese, G.: Tensor-scalar gravity and binary pulsar experiments. Phys. Rev. D54, 1474 (1996b). gr-qc/9602056

    MathSciNet  ADS  Google Scholar 

  22. Damour, T., Esposito-Farese, G.: Gravitational-wave versus binary-pulsar tests of strong-field gravity. Phys. Rev. D58, 042001 (1998). gr-qc/9803031

    ADS  Google Scholar 

  23. Damour T., Taylor J.H.: Strong-field tests of relativistic gravity and binary pulsars. Phys. Rev. D45, 1840 (1992)

    ADS  Google Scholar 

  24. Damour, T., Piazza, F., Veneziano, G.: Runaway dilaton and equivalence principle violations. Phys. Rev. Lett. 89, 081601 (2002). gr-qc/0204094

    Article  ADS  Google Scholar 

  25. Damour, T., Piazza, F., Veneziano, G.: Violations of the equivalence principle in a dilaton-runaway scenario. Phys. Rev. D66, 046007 (2002). hep-th/0205111

    MathSciNet  ADS  Google Scholar 

  26. Dvali, G., Gabadadze, G., Porrati, M.: 4D gravity on a brane in 5D Minkowski space. Phys. Lett. B485, 208 (2000). hep-th/0005016

    MathSciNet  ADS  Google Scholar 

  27. Dvali, G., Gabadadze, G., Porrati, M.: On sub-millimeter forces from extra dimensions. Mod. Phys. Lett. A15, 1717 (2000). hep-ph/0007211

    MathSciNet  ADS  Google Scholar 

  28. Dvali, G., Gruzinov, A., Zaldarriaga, M.: The accelerated universe and the moon. Phys. Rev. D68, 024012 (2003). hep-ph/0212069

    ADS  Google Scholar 

  29. Halverson, N.W., Leitch E.M., Pryke C., Kovac, J., Carlstrom, J.E., Holzapfel, W.L., Dragovan, M., Cartwright, J.K., Mason, B.S., Padin, S., Pearson, T.J., Shepherd, M.C., Readhead, A.C.S.: DASI first results: a measurement of the cosmic microwave background angular power spectrum. Astrophys. J. 568, 38 (2002). astro-ph/0104489

    Article  ADS  Google Scholar 

  30. Lange, Ch., Camilo, F., Wex, N., Kramer, M., Backer, D.C., Lyne, A.G. Doroshenko, O.: Precision timing measurements of PSR J1012+5307. Mon. Not. R. Astron. Soc. 326, 274 (2001)

    Article  ADS  Google Scholar 

  31. Lebach, D.E., Corey, B.E., Shapiro, I.I., Ratner, M.I., Webber, J.C., Rogers, A.E.E., Davis, J.L. Herring, T.A.: Measurement of the solar gravitational deflection of radio waves using very-long-baseline interferometry. Phys. Rev. Lett. 75, 1439 (1995)

    Article  ADS  Google Scholar 

  32. Netterfield, C.B., Ade, P.A.R., Bock, J.J., Bond, J.R., Borrill, J., Boscaleri, A., Coble, K., Contaldi, C.R., Crill, B.P., de Bernardis, P., Farese, P., Ganga, K., Giacometti, M., Hivon, E., Hristov, V.V., Iacoangeli, A., Jaffe, A.H., Jones, W.C., Lange, A.E., Martinis, L., Masi, S., Mason, P., Mauskopf, P.D., Melchiorri, A., Montroy, T., Pascale, E., Piacentini, F., Pogosyan, D., Pongetti, F., Prunet, S., Romeo, G., Ruhl, J.E., Scaramuzzi, F. [i.e. Boomerang Collaboration]: A measurement by BOOMERANG of multiple peaks in the angular power spectrum of the cosmic microwave background. Astrophys. J. 571, 604 (2002). astro-ph/0104460

    Article  ADS  Google Scholar 

  33. Nordtvedt, K.L., Jr.: Probing gravity to the 2nd post-Newtonian order and to one part in 107 using the Sun. ApJ 320, 871 (1987)

    Article  ADS  Google Scholar 

  34. Nordtvedt, K.L., Jr.: Significance of ‘second-order’ light propagation experiments in the solar system. Class. Quantum Gravity 13, A11 (1996)

    Article  MATH  ADS  Google Scholar 

  35. Nordtvedt, K.L., Jr.: Lunar laser ranging—a comprehensive probe of post-Newtonian gravity (2003). gr-qc/0301024

  36. Peebles, P.J.E., Ratra, B.: The cosmological constant and dark energy. Rev. Mod. Phys. 75, 599 (2003). astro-ph/0207347

    Article  MathSciNet  ADS  Google Scholar 

  37. Peacock, J.A., et al.: A measurement of the cosmological mass density from clustering in the 2dF galaxy redshift survey. Nature 410, 169 (2001)

    Article  ADS  Google Scholar 

  38. Perlmutter, S., Aldering, G., Goldhaber, G., Knop, R.A., Nugent, P., Castro, P.G., Deustua, S., Fabbro, S., Goobar, A., Groom, D.E., Hook, I.M., Kim, A.G., Kim, M.Y., Lee, J.C., Nunes, N.J., Pain, R., Pennypacker, C.R., Quimby, R., Lidman, C., Ellis, R.S., Irwin, M., McMahon, R.G., Ruiz-Lapuente, P., Walton, N., Schaefer, B., Boyle, B.J., Filippenko, A.V., Matheson, T., Fruchter, A.S., Panagia, N., Newberg, H.J.M., Couch, W.J. [i.e. Supernova Cosmology Project Collaboration]: Measurements of omega and lambda from 42 high-redshift supernovae. Astrophys. J. 517, 565 (1999). astro-ph/9812133

    Article  ADS  Google Scholar 

  39. Pitjeva, E.V.: Relativistic effects and solar oblateness from radar observations of planets and spacecraft. Astron. Lett. 31, 340 (2005)

    Article  ADS  Google Scholar 

  40. Plowman, J.E., Hellings, R.W.: LATOR covariance analysis. Class. Quantum Gravavity 23, 309 (2006). gr-qc/0505064

    Article  MATH  ADS  Google Scholar 

  41. Reasenberg, R.D., Shapiro, I.I., MacNeil, P.E., Goldstein, R.B., Breidenthal, J.C., Brenkle, J.P., Cain, D.L., Kaufman, T.M., Komarek, T.A., Zygielbaum, A.I.: Viking relativity experiment: verification of signal retardation by solar gravity. ApJ Lett. 234, L219 (1979)

    Article  ADS  Google Scholar 

  42. Robertson, D.S., Carter, W.E., Dillinger, W.H.: A new measurement of solar gravitational deflection of radio signals using VLBI. Nature 349, 768 (1991)

    Article  ADS  Google Scholar 

  43. Riess, A.G., Filippenko, A.V., Challis, P., Clocchiatti, A., Diercks, A., Garnavich, P.M., Gilliland, R.L., Hogan, C.J., Jha, S., Kirshner, R., Leibundgut, B., Phillips, M.M., Reiss, D., Schmidt, B.P., Schommer, R.A., Smith, R.C., Spyromilio, J., Stubbs, C., Suntzeff, N.B., Tonry, J.: Observational evidence from supernovae for an accelerating universe and a cosmological constant. [i.e., Supernova Search Team Collaboration] Astron. J. 116, 1009 (1998)

    ADS  Google Scholar 

  44. Shapiro, I.I., Counselman, C.C., III, King, R.W.: Verification of the principle of equivalence for massive bodies. Phys. Rev. Lett. 36, 555 (1976)

    Article  ADS  Google Scholar 

  45. Shapiro, I.I., Reasenberg, R.D., MacNeil, P.E., Goldstein, R.B., Brenkle, J.P., Cain, D.L., Komarek, T., Zygielbaum, A.I., Cuddihy, W.F., Michael, W.H., Jr.: The viking relativity experiment. JGR 82, 4329 (1977)

    Article  ADS  Google Scholar 

  46. Shapiro, S.S., Davis, J.L., Lebach, D.E., Gregory, J.S.: Measurement of the solar gravitational deflection of radioWaves using geodetic very-long-baseline interferometry data, 1979–1999. Phys. Rev. Lett. 92, 121101 (2004)

    Article  ADS  Google Scholar 

  47. Taylor, J.H., Wolszczan, A., Damour, T., Weisberg, J.M.: Experimental constraints on strong-field relativistic gravity. Nature 355, 132 (1992)

    Article  ADS  Google Scholar 

  48. Tonry, J.L., Schmidt, B.P., Barris, B., Candia, P., Challis, P., Clocchiatti, A., Coil, A.L., Filippenko, A.V., Garnavich, P., Hogan, C., Holland, S.T., Jha, S., Kirshner, R.P., Krisciunas, K., Leibundgut, B., Li, W., Matheson, T., Phillips, M.M., Riess, A.D., Schommer, R., Smith, R.C., Sollerman, J., Spyromilio, J., Stubbs, C.W., Suntzeff, N.B.: Cosmological results from high-z supernovae. Astrophys. J. 594, 1–24 (2003). astro-ph/0305008

    Google Scholar 

  49. Turyshev, S.G., Shao, M., Nordtvedt, K.L., Jr.: The Laser Astrometric Test of Relativity (LATOR) mission. Class. Quantum Gravity 21, 2773 (2004). gr-qc/0311020

    Article  MATH  ADS  Google Scholar 

  50. Turyshev, S.G., Shao, M., Nordtvedt, K.L., Jr.: Experimental design for the LATOR mission. Int. J. Mod. Phys. D13, 2035 (2004). gr-qc/0410044

    ADS  Google Scholar 

  51. Turyshev, S.G., Shao, M., Nordtvedt, K.L., Jr.: Optical design for the Laser Astrometric Test of Relativity. In: Proc. The XXII Texas Symposium on Relativistic Astrophysics. Stanford University, 13–17 December 2004, eConf C041213 #0306 (2004). gr-qc/0502113

  52. Turyshev, S.G., Shao, M., Nordtvedt, K.L., Jr.: Science, technology and mission design for the Laser Astrometric Test of Relativity mission. 359th WE-heraeus Seminar: Lasers, Clock, and Drag-free: Technologies for Future Exploration in Space and Gravity Tests. University of Bremen, ZARM, Bremen, Germany, 30 May–1 June 2005. In: Dittus, H., Laemmerzahl, C., Turyshev, S. (eds.) Lasers, Clocks, and Drag-free: Technologies for Future Exploration in Space and Tests of Gravity: Proceedings, pp. 429-493. Springer Verlag (2006). arXiv:gr-qc/0601035

  53. Turyshev, S.G., Israelsson, U.E., Shao, M., Yu, N., Kusenko, A., Wright, E.L., Everitt, C.W.F., Kasevich, M., Lipa, J.A., Mester, J.C., Reasenberg, R.D., Walsworth, R.L., Ashby, N., Gould, H., Paik, H.J.: Space-based research in fundamental physics and quantum technologies. Int. J. Mod. Phys. D 16(12a), 1879–1925 (2007). arXiv:0711.0150 [gr-qc]

    Article  ADS  Google Scholar 

  54. Turyshev S. G.: Experimental tests of general relativity. Annu. Rev. Nucl. Part. Sci. 58, 207–248 (2008). arXiv:0806.1731 [gr-qc]

    Article  ADS  Google Scholar 

  55. Will, C.M.: Theory and experiment in gravitational physics. Cambridge: Cambridge University Press (1993)

    MATH  Google Scholar 

  56. Will, C.M.: The confrontation between general relativity and experiment. Liv. Rev. Relativity 9 (2006). gr-qc/0510072

  57. Williams, J.G., Turyshev, S.G., Boggs, D.H.: Progress in lunar laser ranging tests of relativistic gravity. Phys. Rev. Lett. 93, 261101 (2004) gr-qc/0411113

    Article  ADS  Google Scholar 

Download references

Acknowledgements

The work described here was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration.

Author information

Authors and Affiliations

Authors

Corresponding author

Correspondence to H. Dittus.

Rights and permissions

Reprints and permissions

About this article

Cite this article

Turyshev, S.G., Shao, M., Nordtvedt, K.L. et al. Advancing fundamental physics with the Laser Astrometric Test of Relativity. Exp Astron 27, 27 (2009). https://doi.org/10.1007/s10686-009-9170-9

Download citation

  • Received:

  • Accepted:

  • Published:

  • DOI: https://doi.org/10.1007/s10686-009-9170-9

Keywords

PACS

Navigation