![]() Scientists can tell by monitoring the slightest wobbles as the Moon rotates. This is about the thickness of an orange peel.īesides the Earth-Moon drift, such measurements over a long period of time and across several reflectors have revealed that the Moon has a fluid core. In the meantime, scientists continue to rely on the surface reflectors to learn new things, despite the weaker signal.īy measuring how long it takes laser light to bounce back - about 2.5 seconds on average - researchers can calculate the distance between Earth laser stations and Moon reflectors down to less than a few millimeters. The Art of Sending a Photon Beam to the Moon … and Getting it Back ![]() The researchers are refining their technique so they can collect more measurements. Whatever the cause, scientists could then account for it in their data analysis.ĭespite their first successful laser-ranging experiments, Mazarico and his team haven’t settled the dust question just yet. They figured that if they found a discrepancy in the light returned from LRO’s reflector versus the surface ones, they could use computer models to test whether dust, or something else, is responsible. Scientists hoped to use LRO’s reflector to determine if that’s true. As a result, the dust could be blocking light from reaching the mirrors and also insulating the mirrors and causing them to overheat and become less efficient. Some experts suspect that dust may have settled on these reflectors over time, possibly after getting kicked up by micrometeorite impacts to the Moon’s surface. Collectively, these reflectors comprise the last working science experiment from the Apollo era. Soviet robotic rovers called Lunokhod 1 and 2, which landed in 19, carry two additional reflectors, with 14 mirrors each. Another panel with 300 corner cubes was dropped off by Apollo 15 astronauts in 1971. They are each made of 100 mirrors that scientists call “corner cubes,” as they are corners of a glass cube the benefit of these mirrors is that they can reflect light back to any direction it comes from. Two were delivered by Apollo 11 and 14 crews in 19, respectively. There are five reflecting panels on the Moon. “Laser-ranging science is a long game,” Mazarico said.īut if scientists are to continue using the surface panels far into the future, they need figure out why some of them are returning only a 10th of the expected signal. “Now that we’ve been collecting data for 50 years, we can see trends that we wouldn’t have been able to see otherwise,” said Erwan Mazarico, a planetary scientist from NASA’s Goddard Space Flight Center in Greenbelt, Maryland who coordinated the LRO experiment that was described on August 7 in the journal Earth, Planets and Space. This widening gap is the result of gravitational interactions between the two bodies. One of the biggest revelations is that the Earth and Moon are slowly drifting apart at the rate that fingernails grow, or 1.5 inches (3.8 centimeters) per year. Decades of making this one measurement has led to major discoveries. It’s a fairly straightforward experiment: Aim a beam of light at the reflector and clock the amount of time it takes for the light to come back. ![]() Scientists have been using reflectors on the Moon since the Apollo era to learn more about our nearest neighbor. ![]() These older reflectors are returning a weak signal, which is making it harder to use them for science. One reason engineers placed the reflector on LRO was so it could serve as a pristine target to help test the reflecting power of panels left on the Moon’s surface about 50 years ago. The reflector NASA scientists aimed for is mounted on the Lunar Reconnaissance Orbiter (LRO), a spacecraft that has been studying the Moon from its orbit since 2009. They announced today, in collaboration with their French colleagues, that they received signal back for the first time, an encouraging result that could enhance laser experiments used to study the physics of the universe. Dozens of times over the last decade NASA scientists have launched laser beams at a reflector the size of a paperback novel about 240,000 miles (385,000 kilometers) away from Earth.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |