Category Archives: The Moon
On August 2, 1971, at the end of the last EVA of the Apollo 15 mission, Commander David Scott took a few minutes to conduct a classic science experiment in front of the TV camera that had been set up just outside the LM Falcon at the Hadley Rille landing site. Scott, a former Air Force pilot, recreated a famous demonstration often attributed to Galileo (which may or may not have actually been performed by the astronomer in Pisa in 1586) that shows how objects of different masses react the same way to gravity when dropped – that is, they fall at the same rate.
By performing the “acceleration test” in the vacuum environment of space (but where there is still an observable downward pull of gravity) the Earthly factor of air resistance is negated – especially on such a low-mass and low-density object as a falcon feather – thereby creating a more “pristine” setting for the centuries-old experiment than could ever be achieved here.
When you look up at a full or full-ish Moon you can’t help but notice the large dark spots that mark its Earth-facing side. These form the face of what many call the “Man in the Moon” (or the body of a Moon rabbit, to others) and are individually called mare (“MAR-ay”) which is the Latin word for sea. Early astronomers thought they were bodies of water, but in reality they are solidified dark lava flows from ancient lunar impact events that occurred several billion years ago.
One of the biggest lunar seas, Mare Imbrium (see above), had for a while been thought to have been created by the impact of an asteroid or meteorite somewhere around 50 miles across, based solely on computer models.
Now, research conducted by Brown University professor Dr. Peter Schultz—a specialist in lunar and planetary impacts—indicates that the object that formed Mare Imbrium was likely more massive and of much larger size than once thought…perhaps even as big as 190 miles wide.
Everyone knows that Apollo 11 commander Neil A. Armstrong was the first human to set foot on the Moon (and if you didn’t know, that occurred on July 20, 1969 – yes, it really happened). It was a momentous, history-making event that many (like myself) consider one of the most impressive achievements of humankind. But oddly enough, even with high-resolution Hasselblad film cameras there on location, there are very few photos showing Armstrong himself on the surface of the Moon. In fact the one above, an otherwise very nice panorama captured by fellow Apollo 11 astronaut Buzz Aldrin, really is the best image in existence of Armstrong on the Moon.
So…why is that?
This week NASA’s Jet Propulsion Laboratory announced news of an object traveling around the Sun in an orbit that keeps it relatively close to our own planet. The object, a near-Earth asteroid (NEO) less than 300 feet (100 m) across, is designated 2016 HO3 and has in some reports been called a “new” or “mini” moon of Earth…but that’s not entirely true. More accurately 2016 HO3 is what’s known as a quasi-satellite, and is in a temporary (albeit long-lived by human standards) orbit that takes it on a “leapfrog” path around Earth, never getting closer than 38 times the distance to the Moon—about 9.1 million miles.
Take a ride across the Moon with Apollo 16 commander John Young in this video, a stabilized version of NASA 16mm film footage captured during the first EVA of the mission on April 21, 1972. In what’s called the “lunar Grand Prix” Young pilots the Lunar Roving Vehicle, or LRV, across the dusty terrain of the Descartes highlands, the vehicle’s metal-mesh wheels kicking up plumes of regolith in the near-vacuum and 1/6th Earth gravity environment of the Moon.
If it looks like Young is just having a “grand” time, I’m sure he is—but he wasn’t just hot-rodding. Part of the mission was to evaluate the performance of the LRV with hard turn maneuvers and sudden stops.
Built for NASA by Boeing, the LRVs were stored in a folded position belowdecks on the descent stage of the Landing Modules during the Apollo 15, 16, and 17 missions. They allowed astronauts to cover a much wider area, carry more equipment, and collect more samples while exploring the lunar surface than they could on foot—er, boot. During Apollo 16 John Young and Charlie Duke drive a total of 16.6 miles (26.7 km) during over 20 hours of EVAs. Learn more about the Apollo LRVs here.
Video via YouTube user britoca