A5101691771- Planetary Science and Exploration
- Geophysics and Gravity Measurements
- Adaptive optics and wavefront sensing
- Radio Astronomy Observations and Technology
- Astronomy and Astrophysical Research
- Cosmology and Gravitation Theories
- Gamma-ray bursts and supernovae
- Astro and Planetary Science
- Space Exploration and Technology
- Space Science and Extraterrestrial Life
- Solar and Space Plasma Dynamics
- Pulsars and Gravitational Waves Research
- Astronomical Observations and Instrumentation
- Scientific Research and Discoveries
- Space exploration and regulation
- Relativity and Gravitational Theory
- Global Energy and Sustainability Research
- GNSS positioning and interference
- Stellar, planetary, and galactic studies
- Galaxies: Formation, Evolution, Phenomena
- Space Satellite Systems and Control
- History and Developments in Astronomy
- Calibration and Measurement Techniques
- Advanced Optical Sensing Technologies
- Inertial Sensor and Navigation
University of California, San Diego
2012-2024
Center for Anti-Slavery Studies
2008
University of Washington
2002-2003
California Institute of Technology
1998-2001
TMT Observatory
2001
Palomar College
2001
Dublin Institute For Advanced Studies
1959-1960
Yale University
1943
Lunar laser ranging has provided many of the best tests gravitation since first Apollo astronauts landed on Moon. The march to higher precision continues this day, now entering millimeter regime, and promising continued improvement in scientific results. This review introduces key aspects technique, details motivations, observables, results for a variety science objectives, summarizes current state art, highlights new developments field, describes modeling challenges, looks future enterprise.
A next-generation lunar laser ranging apparatus using the 3.5 m telescope at Apache Point Observatory in southern New Mexico has begun science operation. APOLLO (the Lunar Laser-ranging Operation) achieved one-millimeter range precision to moon which should lead approximately one-order-of-magnitude improvements of several tests fundamental properties gravity. We briefly motivate scientific goals, and then give a detailed discussion instrumentation.
Lunar laser ranging (LLR) has for decades stood at the forefront of tests gravitational physics, including equivalence principle (EP). Current LLR results on EP achieve a sensitivity ofa/a ≈ 10 −13 based few-centimeter data/model fidelity. A recent push in LLR, called APOLLO (the Apache Point Observatory Laser-ranging Operation) produces millimeter-quality data. This paper demonstrates few-millimeter range precision achieved by APOLLO, leading to an expectation that will be able extend...
Accurate analysis of precision ranges to the Moon has provided several tests gravitational theory including Equivalence Principle, geodetic precession, parameterized post-Newtonian (PPN) parameters γ and β, constancy constant G. Since beginning experiment in 1969, uncertainties these have decreased considerably as data accuracies improved time span lengthened. We are exploring modeling improvements necessary proceed from cm mm range enabled by new Apache Point Observatory Lunar Laser-ranging...
In 2006 April, the Apache Point Observatory Lunar Laser-ranging Operation (APOLLO) began its science campaign to measure Earth-Moon separation millimeter precision. Since that time more than 280 "normal-point" measurements have been made of distance between (APO) 3.5-m telescope in New Mexico and retro-reflector arrays on surface Moon. If only statistical errors are considered, then median nightly range measurement uncertainty for all our data is 1.8 mm one-way path, 1.1 after 2007...
Phobos Laser Ranging (PLR) is a concept for space mission designed to advance tests of relativistic gravity in the solar system. PLR's primary objective measure curvature around Sun, represented by Eddington parameter $\gamma$, with an accuracy two parts $10^7$, thereby improving today's best result orders magnitude. Other goals include measurements time-rate-of-change gravitational constant, $G$ and inverse square law at 1.5 AU distances--with up orders-of-magnitude improvement each. The...
Gravitomagnetism--a motional coupling of matter analogous to the Lorentz force in electromagnetism--has observable consequences for any scenario involving differing mass currents. Examples include gyroscopes located near a rotating massive body and interaction two orbiting bodies. In former case, resulting precession gyroscope is often called "frame dragging" principal measurement sought by Gravity Probe-B experiment. The latter case realized Earth-Moon system, effect has fact been confirmed...
This age of modernity is characterized by consistent growth in energy use, economic activity, and resource consumption, a generally increasing standard living—albeit inequitably distributed. All currently living humans, most academic disciplines, have developed this age, which appears normal indefinite to us. But has been enabled the rapid accelerating expenditure our one-time inheritance fossil fuels, drawing down resources ecosystems finite Earth—none can be sustained as we transition from...
Abstract The Apache Point Lunar Laser-ranging Operation (APOLLO) has been collecting lunar range measurements for 15 yr at millimeter accuracy. median nightly uncertainty since 2006 is 1.7 mm. A recently added Absolute Calibration System (ACS), providing an independent assessment of APOLLO system accuracy and the capability to correct data, revealed a ∼0.4% (10 ps) systematic error in calibration one piece hardware that present entire history APOLLO. application ACS-based timing corrections...
Many corner cube prisms, or retroreflectors, employ total internal reflection (TIR) via uncoated rear surfaces. The different elliptical polarization states emerging from the six unique paths through complicate far-field diffraction pattern by introducing various phase delays between paths. In this paper, we present a computational framework to evaluate TIR cubes for arbitrary incidence angles and input states, presenting example output key normal-incidence conditions. We also describe...
Abstract We present data from the Apache Point Observatory Lunar Laser-ranging Operation (APOLLO) covering 15 yr span 2006 April through end of 2020. APOLLO measures Earth–Moon separation by recording round-trip travel time photons to five retro-reflector arrays on Moon. The set, combined with 50 archive measurements other lunar laser ranging (LLR) stations, can be used probe fundamental physics such as gravity and Lorentz symmetry, well properties Moon itself. show that range performed...
We present near-infrared spectroscopy for a complete sample of 33 ultraluminous infrared galaxies at resolution R\approx 1000. Most the wavelength range from 1.80-2.20 microns in rest frame is covered, including Pa-alpha and Br-gamma hydrogen recombination lines, molecular vibration-rotation 1-0 S(1) S(3) lines. Other species, such as He I, [Fe II], [Si VI] appear spectra well, addition to number weaker Nuclear extractions each individual are presented here, along with secondary nuclei,...
APOLLO (the Apache Point Observatory Lunar Laser-ranging Operation) is a new effort in lunar laser ranging that uses the Apollo-landed retroreflector arrays to perform tests of gravitational physics. It achieved its first range return October 2005, and began science campaign following spring. The strong signal (> 2500 photons ten-minute period) translates one-millimeter random uncertainty, constituting at least an order-of-magnitude gain over previous stations. One-millimeter precision...
A Reply to the Comment by Sergei M. Kopeikin.Received 14 March 2007DOI:https://doi.org/10.1103/PhysRevLett.98.229002©2007 American Physical Society
Uncoated corner cube retroreflectors (CCRs) operating via total internal reflection (TIR) are less susceptible to heating than their metal-coated analogs, lacking an absorber on the rear surface. Even so, environments that induce differential within CCR will result in thermal lensing of incident wavefront, introducing aberrations generally reduce central irradiance polarization-sensitive far-field diffraction pattern (FFDP). In this paper, we characterize sensitivity TIR CCRs axial and...
The technique of lunar laser ranging (LLR) has for many decades contributed to cutting-edge tests the fundamental nature gravity. These include best date strong equivalence principle, time-rate-of-change gravitational constant, gravitomagnetism, inverse square law, and preferred frame effects. phenomenologies each are briefly discussed, followed by an extended discussion gravitomagnetism. Finally, new APOLLO project is summarized, which achieves range precision as low one millimeter.
Lunar laser ranging provides a number of leading experimental tests gravitation -- important in our quest to unify General Relativity and the Standard Model physics. The Apache Point Observatory Laser-ranging Operation (APOLLO) has for years achieved median range precision at ~2 mm level. Yet residuals model-measurement comparisons are an order-of-magnitude larger, raising question whether data not nearly as accurate they precise, or if models incomplete ill-conditioned. This paper describes...