The Moon might seem like a poor place to hunt for water, but in fact there’s a decent amount of the stuff dispersed throughout the lunar soil — and even more of it existing as ice deposits in the dark recesses of polar craters. While the LCROSS mission crashed a rocket stage into one of these craters in October 2009 and confirmed evidence of water in the resulting plume of debris, there haven’t been any definitive maps made of water deposits across a large area on the Moon — until now.
Over the course of several years, NASA’s Lunar Reconnaissance Orbiter scanned the Moon’s south pole using its Lunar Exploration Neutron Detector (LEND) to measure how much hydrogen is trapped within the lunar soil. Areas exhibiting suppressed neutron activity — shown above in blue — indicate where hydrogen atoms are concentrated most, strongly suggesting the presence of water molecules… aka H2O.
The incredibly-sensitive LEND instrument measures the flux of neutrons from the Moon, which are produced by the continuous cosmic ray bombardment of the lunar surface. Even a fraction of hydrogen as small as 100 ppm can make a measurable change in neutron distribution from the surface of worlds with negligible atmospheres, and the hydrogen content can be related to the presence of water.
No other neutron instrument with LEND’s imaging capability has ever been flown in space.
Watch the video below for more details as to how LRO and LEND obtained these results:
“While previous lunar missions have observed indications of hydrogen at the Moon’s south pole, the LEND measurements for the first time pinpoint where hydrogen, and thus water, is likely to exist.”
What’s so important about finding water on the Moon? Well besides helping answer the question of where water on Earth and within the inner Solar System originated, it could also be used by future lunar exploration missions to produce fuel for rockets, drinking water, and breathable air. Read more here.
“That’s one small step for man… one giant leap for mankind.” And with those famous words astronaut Neil A. Armstrong awed the entire world on July 21, 1969, becoming the first human to set a booted foot upon a world other than our own. But the historic statement itself has caused no small bit of confusion and controversy over the years, from whether Armstrong came up with it on the spot (he didn’t) to what he actually said… small step for “man?” Where’s the “a?”
Although some have said that the article was left out or cut off (and admittedly it sure sounds that way to me) it turns out it’s probably been there the whole time, hidden behind Neil’s native Ohio accent.
According to a team of speech scientists and psychologists from Michigan State University (MSU) in East Lansing and The Ohio State University (OSU) in Columbus, it is entirely possible that Armstrong said what he had always claimed — though evidence indicates that most people are likely to hear “for man” instead of “for a man” on the Apollo 11 broadcast recordings.
By studying how speakers from Armstrong’s native central Ohio pronounce “for” and “for a,” the team’s results suggest that his “a” was acoustically blended into his “for.”
“Prior acoustic analyses of Neil Armstrong’s recording have established well that if the word ‘a’ was spoken, it was very short and was fully blended acoustically with the preceding word,” says Laura Dilley of Michigan State University. “If Armstrong actually did say ‘a,'” she continues, “it sounded something like ‘frrr(uh).'”
His blending of the two words, compounded with the poor sound quality of the television transmission, has made it difficult to corroborate his claim that the “a” is there.
“If Armstrong actually did say ‘a,’ it sounded something like ‘frrr(uh).'”
– Laura Dilley, Michigan State University
Dilley and her colleagues used a collection of recordings of conversational speech from 40 people raised in Columbus, Ohio, near Armstrong’s native town of Wapakoneta. Within this body of recordings, they found 191 cases of “for a.” They matched each of these to an instance of “for” as said by the same speaker and compared the relative duration. They also examined the duration of Armstrong’s “for (a”) from the lunar transmission.
The researchers found a large overlap between the relative duration of the “r” sound in “for” and “for a” using the Ohio speech data. The duration of the “frrr(uh)” in Armstrong’s recording was 0.127 seconds, which falls into the middle of this overlap. In other words, the researchers conclude, the lunar landing quote is highly compatible with either possible interpretation though it is probably slightly more likely to be perceived as “for” regardless of what Armstrong actually said.
Dilley says there may have been a “perfect storm of conditions” for the word “a” to have been spoken… but not heard.
“We’ve bolstered Neil Armstrong’s side of the story,” she says. “We feel we’ve partially vindicated him. But we’ll most likely never know for sure exactly what he said based on the acoustic information.”
(Personally, I feel that if the first man to walk on the Moon said he said “a,” then he said “a.”)
If you were looking up at the Moon on March 17, 2013 at 03:50:55 UTC, you might have seen one of the brightest “lunar flashes” ever witnessed. And it would have been visible with just the naked eye.
“On March 17, 2013, an object about the size of a small boulder hit the lunar surface in Mare Imbrium,” says Bill Cooke of NASA’s Meteoroid Environment Office. “It exploded in a flash nearly 10 times as bright as anything we’ve ever seen before.”
The scientists estimate that the flash came from a 40 kg meteoroid measuring 0.3 to 0.4 meters wide hitting the Moon, likely traveling about 90,000 km/hr (56,000 mph.) The resulting explosion packed as much punch as 5 tons of TNT.
(FYI, lunar meteors hit the ground with so much kinetic energy that they don’t require an oxygen atmosphere to create a visible explosion. The flash of light comes not from combustion but rather from the thermal glow of molten rock and hot vapors at the impact site.)
The crater could be as wide as 20 meters. The scientists for the Lunar Reconnaissance Orbiter are hoping to image the impact site the next time the spacecraft passes over the area. It should be relatively easy to spot, and lunar scientists are always on the lookout for recent impacts. Additionally, comparing the size of the crater to the brightness of the flash would give researchers a valuable “ground truth” measurement to validate lunar impact models.
Were you observing the Moon that night? Universe Today’s David Dickinson pointed out to me that it is quite possible an amateur could have caught it; however no amateur images have surfaced yet. The Moon would’ve been a waxing crescent and visible to the Pacific region and US West Coast at the time. If you have archived images or video, it might be worth a look. And we’d love to hear from you if you happened to catch anything! NASA said the impact site would have glowed like a 4th magnitude star for about one second.
During the past 8 years, Cooke and a team of NASA astronomers have been monitoring the Moon for signs of explosions caused by meteoroids hitting the lunar surface.
Ron Suggs, an analyst at the Marshall Space Flight Center, was the first to notice the March 17th impact in a digital video recorded by one of the monitoring program’s 14-inch telescopes. “It jumped right out at me, it was so bright,” he said.
During the 8 years of observations, the team has found that the flashes on the Moon are more common than anyone expected, with hundreds of detectable impacts occurring every year.
Since the monitoring program began in 2005, NASA’s lunar impact team has detected more than 300 strikes, most orders of magnitude fainter than the March 17th event. Statistically speaking, more than half of all lunar meteors come from known meteoroid streams such as the Perseids and Leonids. The rest are sporadic meteors–random bits of comet and asteroid debris of unknown parentage.
Cooke believes the lunar impact might have been part of a much larger event.
“On the night of March 17, NASA and University of Western Ontario all-sky cameras picked up an unusual number of deep-penetrating meteors right here on Earth,” he said. “These fireballs were traveling along nearly identical orbits between Earth and the asteroid belt.”
This means Earth and the Moon were pelted by meteoroids at about the same time.
“My working hypothesis is that the two events are related, and that this constitutes a short duration cluster of material encountered by the Earth-Moon system,” said Cooke.
One of the goals of the lunar monitoring program is to identify new streams of space debris that pose a potential threat to the Earth-Moon system. The March 17th event seems to be a good candidate.
This very creative self-portrait by astrophotographer Miguel Claro shows what appears to be the photographer taking a ‘macro’ closeup of the crescent Moon! But there is a lot more going on in this image. The crescent Moon has just 3% of the disc illuminated by the Sun, but there is a stunningly bright Earthshine effect visible. This image was taken on May 11, 2013, so there is a conjunction between the Moon and Jupiter (the brightest star in the image). Venus was also in conjunction, but at the time this image was taken, it was covered by the cloudy band low on the horizon.
Another shot below:
Images taken from Capuchos, Almada, Portugal with a Canon 50D – ISO400; Exp. 2sec. F/4; 35mm, on May 11, 2013 at 21:41 and 21:43. Enjoy more of Claro’s images at his website.
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Has Venus finally come out of hiding? For the past couple months it’s kept close to the sun, hidden in its glare, but come Friday, sky watchers in mid-northern latitudes may get their first shot at seeing the planet’s return to the evening sky.
It won’t be easy, but you’ll have help from the knife-edged crescent moon. Like a spring bloom raising its head from the dark earth, Venus will poke just 4 degrees above the western horizon a half hour after sunset. The moon will be about 2 degrees to the lower left of the planet. Seeing both requires a wide open view to the west and a clean, cloudless sky. It also helps to know when the sun sets for your location – easily found by clicking HERE.
Take along a pair of binoculars. They’ll help fish out both moon and planet in the bright twilight sky. It’s also advantageous to arrive at your viewing spot a little early. Enjoy the sunset, and then take a minute to make sure you’re binoculars are focused at infinity. If you don’t, Venus will be a blur and much harder to find. I usually focus mine on a cloud or the very farthest thing out along the horizon.
Once you’re all set, point your binoculars in the sunset direction and slowly sweep back and forth. Venus will be a short distance to the left or south of the brightest glow remaining along the horizon. Since most binoculars have a field of view of 4 or 5 degrees, when you place the horizon at the bottom of the view, the moon should appear in the middle of the field and Venus up near the top. Look higher and lower and farther left and right to be thorough. Once spotted in binoculars, take the visual challenge and see if you can find it without optical aid.
If you succeed, you’ll be rewarded with an elegant eyeful. Swamped in skylight, Venus will appear unusually meek but still possess its classic fiery brilliance. The newborn crescent will float just a degree and a half (three full moon diameters) away. From the U.S. east coast, the moon will be just 24 hours old; from the west coast 27 hours. Seeing such a young moon is a rarity in itself, but in the company of Venus that much finer.
Let’s say conditions aren’t ideal and you miss the pair on Friday. Well, try again on Saturday. The moon will be higher and much easier to see. Use it as a bow to shoot an imaginary arrow horizon-ward to Venus. And did I mention Jupiter? The planet that cheerily lit up our winter nights is now departing in the west. Watch for it to have a close encounter with Venus on the nights of May 27-28.
With its perpetual clouds, Venus would be a most distressing planet to any skywatcher unfortunate enough to live there. Yet it’s those same clouds that make it the most brilliant planet in the solar system seen from Earth. Clouds reflect sunlight splendidly. Combined with Venus’ proximity to Earth, it’s no wonder the planet earned the title of goddess of love and beauty.
In the first 3 months of this year, Venus remained close to the sun in the morning sky and difficult to see. Then on March 28, it passed behind the sun on the opposite side of Earth’s orbit; astronomers call the lineup superior conjunction. Seen from Earth, Venus looked like a tiny full moon. We’re now about 6 weeks past conjunction and the planet has begun to peek out into the evening sky. At 98% illuminated, it still looks nearly full through a telescope, but that will change in the coming months as Venus approaches Earth in its speedier orbit. Watch for the goddess to grow larger in apparent size while at the same time slimming down her phase from full to half to crescent. Good luck getting re-acquainted this weekend!
AVAST gentle reader: mild SPOILER(S) and graphic depictions of shattered satellites ahead!
We recently had a chance to catch Oblivion, the first summer blockbuster of the season. The flick delivers on the fast-paced Sci-Fi action as Tom Cruise saves the planet from an invasion of Tom Cruise clones.
But the movie does pose an interesting astronomical question: what if the Earth had no large moon? In the movie, aliens destroy the Earth’s moon, presumably to throw our planet into chaos. You’d think we’d already be outclassed by the very definition of a species that could accomplish such a feat, but there you go.
Would the elimination of the Moon throw our planet into immediate chaos as depicted in the film? What if we never had a large moon in the first place? And what has our nearest natural neighbor in space done for us lately, anyway?
Earth is unique among rocky or terrestrial planets in that it has a relatively large moon. The Moon ranks 5th in diameter to other solar system satellites. It is 27% the diameter of our planet, but only just a little over 1/80th in terms of mass.
Clearly, the Moon has played a role in the evolution of life on Earth, although how necessary it was isn’t entirely clear. Periodic flooding via tides would have provided an initial impetus to natural selection, driving life to colonize the land. Many creatures such as sea turtles take advantage of the Full Moon as a signal to nest and breed, although life is certainly resilient enough to find alternative methods.
The 2000 book Rare Earth by Peter Ward and Donald Brownlee cites the presence of a large moon as just one of the key ingredients necessary in the story of the evolution of life on Earth. A Moon-less Earth is also just one of the alternative astronomical scenarios cited by Arthur Upgreen in his 2005 book Many Skies.
Contrary to its depiction on film, the loss of the Moon wouldn’t throw the Earth into immediate chaos, though the long term changes could be catastrophic. For example, no study has ever conclusively linked the Moon to the effective prediction of terrestrial volcanism and earthquakes, though many have tried. (Yes, we know about the 2003 Taiwanese study, which found a VERY weak statistical signal).
All of that angular momentum in the Earth-Moon system would still have to go somewhere. Our Moon is slowly “braking” the rotation of the Earth to the tune of about 1 second roughly every 67,000 years. We also know via bouncing laser beams off of retro-reflectors left by Apollo astronauts that the Moon is receding from us by about 3.8 cm a year. The fragments of the Moon would still retain its angular momentum, even partially shattered state as depicted in the film.
The most familiar effect the Moon has on Earth is its influence on oceanic tides. With the loss of our Moon, the Sun would become the dominant factor in producing tides, albeit a much weaker one.
But the biggest role the Moon plays is in the stabilization of the Earth’s spin axis over long scale periods of time.
Milankovitch cycles play a long term role in fluctuations in climate on the Earth. This is the result of changes in the eccentricity, obliquity and precession of the Earth’s axis and orbit. For example, perihelion, or our closest point to the Sun, currently falls in January in the middle of the northern hemisphere winter in the current epoch. The tilt of the Earth’s axis is the biggest driver of the seasons, and this varies from 22.1° to 24.5° and back (this is known as the change in obliquity) over a span of 41,000 years. We’re currently at a value of 23.4° and decreasing.
But without a large moon to dampen the change in obliquity, much wider and unpredictable swings would occur. For example, the rotational axis of Mars has varied over a span of 13 to 40 degrees over the last 10 to 20 million years. This long-term stability is a prime benefit that we enjoy in having a large moon .
Perhaps some astronomers would even welcome an alien invasion fleet intent on destroying the Moon. Its light polluting influence makes most deep sky imagers pack it in and visit the family on the week surrounding the Full Moon.
But I have but two words in defense of saving our natural satellite: No eclipses.
We currently occupy an envious position in time and space where total solar and lunar eclipses can occur. In fact, Earth is currently the only planet in our solar system from which you can see the Moon snugly fit in front of the Sun during a total lunar eclipse. It’s 1/400th the size of the Sun, which is also very close to 400 times as distant as the Moon. This situation is almost certainly a rarity in our galaxy; perhaps if alien invaders did show up, we could win ‘em over not by sending a nuclear-armed Tom Cruise after ‘em, but selling them on eclipse tours… Continue reading “Into Oblivion: What If the Earth Had No Moon?”
The lunar eclipse on April 25 was described by astrophotographer Gadi Eidelheit as “the greatest, slightest eclipse I ever saw!” The brief and small eclipse saw just 1.47% of the lunar limb nicked by the dark umbra or shadow from the Earth. It was visible from eastern Europe and Africa across the Middle East eastward to southeast Asia and western Australia. Here are a few more shots, including a serendipitous shot of an airplane flying through the eclipse!
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This is beyond awesome. Use your mouse wheel or the + and – buttons on this incredible interactive view of the Moon to zoom in; use your mouse to let the image take you where you want to go. Click on the button in the lower right to go full screen and you’ll feel like you are in lunar orbit.
If that title seems like an obvious statement to you, it’s ok… it seems pretty obvious to me too. But there are those who have been suggesting — for quite some time, actually — that earthquakes can be triggered or strengthened by solar activity; that, in fact, exceptionally powerful solar flares, coronal mass ejections, and other outpourings from our home star can cause the planet’s crust to shift, shake, and shudder.
Except that that’s simply not true — at least, not according to a recent study by researchers from the USGS.
“Recently there’s been a lot of interest in this subject from the popular press, probably because of a couple of larger and very devastating earthquakes. This motivated us to investigate for ourselves whether or not it was true.”
– Jeffrey Love, USGS Research Geophysicist
Even when an earthquake may have been found to occur on the same day as increased solar activity, at other times during even stronger quakes the Sun may have been relatively quiet, and vice versa.
“There have been some earthquakes like the 9.5 magnitude Chile quake in 1960 where, sure enough, there were more sunspots and more geomagnetic activity than on average,” said Dr. Love. “But then for the Alaska earthquake in 1964 everything was lower than normal. There’s no obvious pattern between solar activity and seismicity, so our results were inconclusive.”
Basically, even though our planet orbits within the Sun’s outer atmosphere and we are subject to the space weather it creates — and there’s still a lot to be learned about that — observations do not indicate any connection between sunspots, flares, and CMEs and the shifting of our planet’s crust (regardless of what some may like to suggest.)
“It’s natural for scientists to want to see relationships between things,” said Love. “Of course, that doesn’t mean that a relationship actually exists!”
The team’s findings were published in the March 16, 2013 online edition of Geophysical Research Letters.
In this image acquired on January 5, Cassini’s near-infrared vision pierced Titan’s opaque clouds to get a glimpse of the dark dune fields across a region called Senkyo.
The vast sea of dunes is composed of solid hydrocarbon particles that have precipitated out of Titan’s atmosphere. Also visible over Titan’s southern pole are the rising clouds of the recently-formed polar vortex.
For a closer look at Titan’s dunes (and to find out what the name Senkyo means) keep reading…
In the image above north on Titan is up and rotated 18 degrees to the right. It was taken using a spectral filter sensitive to wavelengths of near-infrared light centered at 938 nanometers.
The view was obtained at a distance of approximately 750,000 miles (1.2 million kilometers) from Titan.
Titan’s hydrocarbon dunes are found across the moon in a wide swath within 30 degrees of the equator and are each about a kilometer wide and tens to hundreds of kilometers long… and in some cases stand over 100 meters tall. (Source: Astronomy Now.)
Observations of the dunes with Cassini and ESA’s Huygens probe during its descent onto Titan’s surface have shown that the moon experiences seasonally-shifting equatorial winds during equinoxes, similar to what occurs over the Indian Ocean between monsoon seasons.
The name Senkyo refers to the Japanese realm of serenity and freedom from wordly cares and death… in line with the IAU convention of naming albedo features on Titan after mythological enchanted places.
Click here for an earlier view of Senkyo, and follow the Cassini mission here.