![]() More than 15,000 images went into making the base map! And we used LRO's laser altimetry - 4½ billion individual measurements! - to create a companion topographic Moon globe. From LRO imagery we made a true-to-the-eye "visual" globe that's quite dark (as the Moon really is). Moon: Sky & Telescope contempolated making a Moon globe decades ago but held off until NASA's Lunar Reconnaissance Orbiter delivered the enough detailed mapping to cover the globe consistently. If you're at all interested in plate tectonism - the gradual grinding and collision of Earth's interlocking crustal slabs - this is the globe for you! The Sky & Telescope Moon globe (left) compared to the a widely used version created during the 1960s. For undersea features, we relied on bathymetry gathered by the British Oceanographic Data Centre. We got map data for the land portion from a mosaic of thousands of images, known as the Blue Marble, acquired by NASA's Terra and Aqua satellites. For its Earth globe, however, Sky & Telescope's editors wanted to show our home planet the way visiting aliens might see it - crisscrossed by mountains, valleys, and other major geologic structures. Venus is a weird, unique world - its signature geologic features are big, round coronae that are bounded not by high rims but instead deep circular fractures.Įarth: We've all seen globes of Earth that show national boundaries and major cities. But we worked with NASA centers to portray both surface details and elevation in a clear way. Creating a globe of all this data was tricky - the resulting maps portray the radar "brightness" of the surface. Fortunately, in the early 1990s NASA's Magellan orbiter used synthetic aperture radar to record the surface details and measure the global topography. ![]() Its atmosphere is so opaque that, except for a few snapshots from the Soviet Union's Venera landers, we have no photographic views of its hellish surface. No single picture can convey this breadth, but the globe makes it easy. It's only 95 km (59 miles) across, but its formation created a spectacular splash of bright crater rays that extends more than a quarter of the way around Mercury. But the look is subtly different, due to vast stretches of lava-capped plains. Mercury: Because its surface is nearly gray and heavily cratered, you might initially confuse Mercury for the Moon. It's based on 18,000 of the Mercurian surface captured by NASA's Messenger spacecraft. Mercury is a recent addition to Sky & Telescope's series of planetary globes. ![]() And the more I pore over them, the more I learn. Honestly, I need to refer to one or more of these globes almost every day at the office. But they're far more than pretty mini beach balls on the shelf. The result is a set of attractive and eye-catching orbs that attract lots of admiring gazes wherever we show them. We've been fortunate to have found a willing partner in Replogle Globes. Together with S&T's illustration specialists, most notably Gregg Dinderman, we fretted over colors and lavished attention on every label. For each, we worked with planetary scientists and the astrogeology team at the U.S. We started in the 1980s with Mars, added Venus, and more recently completed the set with the Moon, Mercury, and Earth. So, not surprisingly, over the years I've eagerly spearheaded Sky & Telescope's efforts to develop globes of the Moon and terrestrial planets. The Moon, Mars, and Mercury are accurately scaled to a 12-inch Earth globe, and to accomplish that feat the globes had to be specially crafted as solid wood spheres. In fact, one of my most prized possessions is a set of NASA globes from the 1970s. I could spend hours (and have) playing with Google Earth. The National Geographic Atlas of the World is not far from my desk for fact-checking. Sure, I use GPS these days, but my car is still stuffed with road maps. True confession: even from childhood, I have always been a map junkie. ![]() More recently, Sky & Telescope has introduced a 12-inch globe of the innermost planet. Here I am among my favorite toys: globes of the planets! In this photo, taken more than a decade ago, I'm tossing a special NASA scale-model globe of Mercury. Pictures are great, but there's nothing like holding another world in your hands to appreciate its unique characteristics. ![]()
0 Comments
Leave a Reply. |