![]() Getting your hands on the laser is not actually that hard if you know what you're doing. Just 1-3 W would probably be enough if you had good detectors. You don't need a megawatt or even 100 W of average power. We need to distinguish between average and peak power here. I guess you could do all these things on your own, but you would need about $1 million and a couple years of time to set it up. And you need to set this all up in a place with minimal background light and minimal atmospheric distortion (seeing). You need a big telescope to maximize the number of photons you get (we used the 3.5 meter telescope at Apache Point). You need fancy filters and timing electronics, because, when you are only getting 1 photon back, you need to turn the detectors on in as little a time as possible to minimize false detections from background light. You need sensitive detectors because, even if you shoot 10 17 photons up, you're only going to get about 1 photon back (we used avalanche photodiodes). You need laser that can shoot enough photons in a short pulse that you'll get some back in the return pulse (shoot 10 17 green 532 nm photons per pulse). I was a grad student on the APOLLO (Apache Point Observatory Lunar Laser Ranging Operation) project that was shown on Mythbusters. ![]() We make our world significant by the courage of our questions and by the depth of our answers. For more open-ended questions, try /r/AskScienceDiscussion | Sign up to be a panelist!.Looking for flair? Sign up to be a panelist!.Neuroscience, Neurology, Neurochemistry, Cognitive NeuroscienceĪsk Anything Wednesday - Biology, Chemistry, Neuroscience, Medicine, PsychologyĪsk Anything Wednesday - Economics, Political Science, Linguistics, AnthropologyĪsk Anything Wednesday - Physics, Astronomy, Earth and Planetary ScienceĪsk Anything Wednesday - Engineering, Mathematics, Computer science Medicine, Oncology, Dentistry, Physiology, Epidemiology, Infectious Disease, Pharmacy, Human Body Psychology, Cognitive Psychology, Developmental Psychology, Abnormal, Social Psychology Social Science, Political Science, Economics, Archaeology, Anthropology, Linguisticsīiology, Evolution, Morphology, Ecology, Synthetic Biology, Microbiology, Cellular Biology, Molecular Biology, Paleontology Mechanical Engineering, Electrical Engineering, Structural Engineering, Computer Engineering, Aerospace EngineeringĬhemistry, Organic Chemistry, Polymers, Biochemistry Mathematics, Statistics, Number Theory, Calculus, AlgebraĪstronomy, Astrophysics, Cosmology, Planetary FormationĬomputing, Artificial Intelligence, Machine Learning, ComputabilityĮarth Science, Atmospheric Science, Oceanography, Geology ![]() Theoretical Physics, Experimental Physics, High-energy Physics, Solid-State Physics, Fluid Dynamics, Relativity, Quantum Physics, Plasma Physics /r/AskScienceDiscussion: For open-ended and hypothetical questions.FAQ: In-depth answers to many popular questions.Weekly Features: Archives of AskAnything Wednesday, FAQ Fridays, and more!.Be civil: Remember the human and follow Reddiquette.Report comments that do not meet our guidelines, including medical advice.Downvote anecdotes, speculation, and jokes.Upvote on-topic answers supported by reputable sources and scientific research.Answer questions with accurate, in-depth explanations, including peer-reviewed sources where possible. ![]() NASA is exploring various ways of making that happen, including placing reflective panels on new lunar rovers, or sending new reflective panels to different areas of the Moon to get more accurate measurements of its movements.Please read our guidelines and FAQ before posting Ideally, scientists would love to have new sensors placed on the Moon, but doing so would require a new mission to its surface. “But to learn more, scientists first need to know the distance between Earth stations and the moon reflectors to a higher degree of accuracy than the current few millimeters.” “Laser experiments could help reveal if there’s solid material in the moon’s core that would’ve helped power the now-extinct magnetic field,” NASA explains. Because the Moon has been shown to “wobble” slightly, researchers believe that Earth’s tiny neighbor still has a warm fluid core, meaning that it’s not the frozen husk it might appear to be on the surface. The reflectors and the laser experiments have provided scientists with some incredible insights into the Moon’s movement as well as its makeup.
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