Seasonal Streaks Point to Recent Flowing Water on Mars Image Credit: NASA, JPL, U. Arizona
Explanation: What creates these changing streaks on Mars? Called Recurring Slope Linea (RSL), these dark features start on the slopes of hills and craters but don’t usually extend to the bottom. What’s even more unusual is that these streaks appear to change with the season, appearing fresh and growing during warm weather and disappearing during the winter. After much study, including a recent chemical analyses, a leading hypothesis has emerged that these streaks are likely created by new occurrences of liquid salty water that evaporates as it flows. The source for the briny water is still unclear, with two possibilities being condensation from the Martian atmosphere and underground reservoirs. An exciting inference is that if these briny flows are not too salty, they may be able to support microbial life on Mars even today. The featured image of a hill inside Horowitz Crater was investigated by instruments aboard the robotic Mars Reconnaissance Orbiter that has been returning data from Mars since 2006.
Supermoon Total Lunar Eclipse and Lightning Storm Image Credit & Copyright: Jose Antonio Hervás
Explanation: What’s more rare than a supermoon total lunar eclipse? How about a supermoon total lunar eclipse over a lightning storm. Such an electrifying sequence was captured yesterday from Ibiza, an island in southeastern Spain. After planning the location for beauty, and the timing to capture the entire eclipse sequence, the only thing that had to cooperate for this astrophotographer to capture a memorable eclipse sequence was the weather. What looked to be a bother on the horizon, though, turned out to be a blessing. The composite picture features over 200 digitally combined images from the same location over the course of a night. The full moon is seen setting as it faded to red in Earth’s shadow and then returned to normal. The fortuitous lightning is seen reflected in the Mediterranean to the right of the 400-meter tall rocky island of Es Vedra. Although the next total eclipse of a large and bright supermoon will occur in 2033, the next total eclipse of any full moon will occur in January 2018 and be best visible from eastern Asia and Australia.
Explanation: Recorded in 2014 April, this total lunar eclipse sequence looks south down icy Waterton Lake from the Waterton Lakes National Park in Alberta, Canada, planet Earth. The most distant horizon includes peaks in Glacier National Park, USA. An exposure every 10 minutes captured the Moon’s position and eclipse phase, as it arced, left to right, above the rugged skyline and Waterton town lights. In fact, the sequence effectively measures the roughly 80 minute duration of the total phase of the eclipse. Around 270 BC, the Greek astronomer Aristarchus also measured the duration of lunar eclipses – though probably without the benefit of digital clocks and cameras. Still, using geometry, he devised a simple and impressively accurate way to calculate the Moon’s distance, in terms of the radius of planet Earth, from the eclipse duration. This modern eclipse sequence also tracks the successive positions of Mars, above and right of the Moon, bright star Spica next to the reddened lunar disk, and Saturn to the left and below.
The Editor: Are there any scandals this week, LL ?
Honesty The Best Policy Cat–unless you are a politician: There sure are, this is tops so far. This almost qualifies as sleazy enough for our largest banks. Maybe we could bail them out. The VW management almost make the Nazis look ethical.
Tonight: A Supermoon Lunar Eclipse Video Credit: NASA‘s GSFC, David Ladd (USRA) & Krystofer Kim (USRA)
Explanation: Tonight a bright full Moon will fade to red. Tonight’s moon will be particularly bright because it is reaching its fully lit phase when it is relatively close to the Earth in its elliptical orbit. In fact, by some measures of size and brightness, tonight’s full Moon is designated a supermoon, although perhaps the “super” is overstated because it will be only a few percent larger and brighter than the average full Moon. However, our Moon will fade to a dim red because it will also undergo a total lunar eclipse — an episode when the Moon becomes completely engulfed in Earth’s shadow. The faint red color results from blue sunlight being more strongly scattered away by the Earth’s atmosphere. Tonight’s moon can also be called a Harvest Moon as it is the full Moon that occurs closest to the September equinox, a time signaling crop harvest in Earth’s northern hemisphere. Total eclipses of supermoons are relatively rare — the last supermoon lunar eclipse was in 1982, and the next will be in 2033. Tonight’s supermoon total eclipse will last over an hour and be best visible from eastern North America after sunset, South America in the middle of the night, and Western Europe before sunrise.