In 2007, the Japan Aerospace Exploration Agency (JAXA) launched the SELENE lunar orbiter, better known by its nickname Kaguya. As the most ambitious moon mission since the Apollo program, Kaguya spent 20 months surveying the moon and photographing its surface, until JAXA instructed the orbiter to impact near the Gill crater in 2009.
Using those images, video artist Seán Doran recently published two videos depicting a "real-time" lunar orbit that spans more than eight hours.
Kaguya was the first spacecraft to capture high-definition images of the moon. The orbiter was outfitted with two 2.2 megapixel CCD HDTV cameras, one equipped with a telephoto lens, the other a wide-angle. These cameras helped JAXA construct a detailed topography of the moon, with "data points 10 orders larger than the previous model of the lunar surface," NASA noted.
To create the new videos, Doran synthesized the Kaguya images and polished them up by denoising, repairing, grading, retiming and upscaling them to 4k, as he wrote on Twitter.
As a self-taught artist, Doran has created dozens of space-art videos using images collected by instruments like the High Resolution Imaging Science Experiment (HiRISE) and the High Resolution Stereo Camera (HRSC).
"I use Photoshop for 2D work as well as batch processing frames for animation," Doran wrote in a blog post published on the HiRISE website. "I use 3DS Max and Blender for 3D work. I use After Effects, Premiere and Audition for video. I also use a plethora of plugins for each software stack as well as numerous apps for specific tasks. I'm always testing new methods and love trying out new software."
"Making content with HiRISE data has sparked a new chapter in my creative expression, bringing datasets to life through mosaics, animations, VR experiences and short films set to music."
Space has captured the imagination of artists for centuries. Humans living during the Paleolithic and Neolithic periods painted constellations on cave walls. In medieval Europe, artists often personified the planets, viewing the cosmos in a religious context, with Earth at the center of a divine universe. As science progressed, so did space art.
The 20th century saw artists from Pablo Picasso to Andy Warhol capture the cosmos in varying forms. The Russian painter Wassily Kandinsky hinted at the planets abstractly in his 1926 painting "Several Circles," while artists like Agnes Denes used a more mathematical approach to illustrate our own planet from outer space.
Doran's fascination with the cosmos was sparked by a luminary in science education.
"I've been interested in astronomy since being introduced to the concept watching Ann Druyan & Carl Sagan's Cosmos TV series," he wrote. "It was a welcome distraction from the civil war raging in Belfast during the 1980s."
You can check out more of Doran's work on his Flickr account and YouTube channel.
A new look at the Moon
A larger version of the same image.
Credit: NRAO/GBO/Raytheon/NSF/AU
The pictures were produced using radar imaging, a powerful if infrequently used tool in astronomy for creating detailed pictures of places from where visible light can't reach us.
According to a statement released by the NRAO, the Green Bank Telescope (GBT) in West Virginia had a powerful radio transmitter installed. This was used to transmit radio waves towards the Moon which then bounced back into the telescopes of the Very Long Baseline Array (VLBA), which produced the images. The transmission occurred in November of last year.
The image depicts the Hadley–Apennine region of the Moon, most noteworthy for being the Apollo 15 mission's landing site. Highlights include the 6km crater known as Hadley C and the remains of a collapsed lava tube known as Hadley Rille, which winds across the picture like a dried-out river.
The resolution of this image is tremendous. Objects as small as 5 meters (16.4 ft) can easily be seen.
How does it work, exactly?
Using radio waves for astronomy has certain advantages. Visible light waves can have difficulty getting through the Earth's atmosphere. They can be drowned out by light pollution, and have to either be produced by or reflected off the object you want to look at. This can make things difficult for astronomers.
However, radio waves don't face these problems in the same way; waves emitted by extremely distant objects are picked up all the time. In radar astronomy, radio or microwaves are used to produce images of objects that visible light ways might struggle with. The first images of the surface of Venus, which is famously obscured by clouds, were captured this way.
For the most part, it works just like radar here on Earth. Radio waves are transmitted to the Moon, or whatever nearby cosmic object you want to see, and then bounce back to the Earth. Radio telescopes then record the returning waves. In this case, they were picked up by the telescopes of the VLBA, which stretch from Hawaii to the Virgin Islands. The vast distance between the receiving telescopes helps to improve their resolution.
The shape of things to come
This operation was just a proof of concept test. Having proven what the existing transmitter is capable of, efforts will now shift towards building a larger one that will be focused on other objects in the solar system.
Not only will this allow for extremely high-resolution images to be produced, but it may allow us to take closer looks than previously possible at objects which are too dark to show up in the visible light spectrum, such as certain asteroids.
Scientists involved with the project suggest it could be effective at viewing objects as far away as Neptune. Given that the strength of radar detection drops off exponentially with distance, this is quite the achievement.
Karen O'Neil, the Green Bank Observatory site director, explained how impressive this new system could be, "The planned system will be a leap forward in radar science, allowing access to never before seen features of the Solar System from right here on Earth."
Reports suggest the new system will come online no sooner than 2024 and cost millions of dollars if it is greenlit.
As many of you will know, despite the recent collapse of the Arecibo Observatory, it's been an exciting time in radio astronomy, with new discoveries being made on an almost regular basis. With new developments like this, the excitement can be expected to continue for some time.
It's a rhythm that preceded our presence on Earth: The moon's inexorable push and pull on our planet's oceans. According to researchers at University of Tromsø, The Arctic University of Norway, it turns out that the moon does more than move the tides—it also controls the release of methane into the atmosphere from below the Arctic Ocean. There's no reason to think it's not true in other seas as well.
This is yet another example of the complexity of global warming, methane being the other major greenhouse gas. All sorts of things are involved in keeping the environment in balance that one would never expect, like the moon. The study points out that it's not all bad news, however, since as the oceans rise they may help the moon in controlling methane's release.
The study is published in the journal Nature Communications.
Tidal methane
Screenshot of visualization from researchers' data
Credit: Andreia Plaza Faverola
Methane often takes second billing to carbon dioxide in discussions of climate change, likely because it dissipates much more quickly. However, its warming effect is actually far more intense that CO2's — it is 84 times more potent. Methane makes up about 25 percent of our greenhouse gases.
Says co-author of the study Andreia Plaza Faverola, "We noticed that gas accumulations, which are in the sediments within a meter from the seafloor, are vulnerable to even slight pressure changes in the water column. Low tide means less of such hydrostatic pressure and higher intensity of methane release. High tide equals high pressure and lower intensity of the release."
This phenomenon has not been previously observed. While significant gas hydrate concentrations have been sampled in the area, no methane release had been documented. "It is the first time that this observation has been made in the Arctic Ocean," says co-author Jochen Knies. "It means that slight pressure changes can release significant amounts of methane. This is a game-changer and the highest impact of the study."
Detecting the tidal story
Screenshot from video of piezometer out of the water
Credit: Przemyslaw Domel
The researchers buried a tool called a piezometer in the sediment on the ocean floor, and left it in place for four days. During that time, the instrument made hourly measurements of pressure and temperature in the sediments, and these indicated the presence of methane close to the sea floor, increasing at low tide and decreasing at high tide.
Their first notable observation was, of course, the presence of the gas on the Arctic Ocean floor despite a lack of other more visible indicators of its presence. "This tells us that gas release from the seafloor is more widespread than we can see using traditional sonar surveys," says Plaza Faverola. "We saw no bubbles or columns of gas in the water." She credits the watchful presence of the piezometer for making the discovery: "Gas burps that have a periodicity of several hours won't be identified unless there is a permanent monitoring tool in place, such as the piezometer."
Enthuses Knies, "What we found was unexpected and the implications are big. This is a deep-water site. Small changes in pressure can increase the gas emissions but the methane will still stay in the ocean due to the water depth."
Of course, not all the Earth's waters are equally deep, and there may not be enough water weight in some places to contain the methane below. "But what happens in shallower sites?" asks Knies. "This approach needs to be done in shallow Arctic waters as well, over a longer period. In shallow water, the possibility that methane will reach the atmosphere is greater."
The weight of water
The basic mechanics at play are simple. Higher tides mean more water pressing down on the methane, and this increased pressure keeps it from rising away from the sea floor. Low tide means less water, less pressure, and a greater opportunity for the methane to escape.
The researchers note in their study that this simple relationship may actually offer a silver lining to the rising of the world's ocean as the planet cools. There will be more water, and thus more pressure to keep methane from escaping up and into the atmosphere. In essence, higher sea levels may have something of a cooling effect by keeping methane out of the atmosphere.
In the end, there's not much we can do about the Moon and its tides, but the more knowledge we have of the mechanisms behind climate change the better.
As Plaza Faverola puts it:
"Earth systems are interconnected in ways that we are still deciphering, and our study reveals one of such interconnections in the Arctic: The moon causes tidal forces, the tides generate pressure changes, and bottom currents that in turn shape the seafloor and impact submarine methane emissions. Fascinating!"
For the first time, scientists have confirmed the presence of water on the sunlit surface of the moon, a discovery with major implications for future moon missions and deep-space exploration.
Since the 1990s, a series of observations have suggested the moon harbors ice, but scientists haven't been able to confirm whether the data was signaling the presence of water (H2O) or a chemical relative called hydroxyl, which is oxygen bonded with hydrogen. In 2018, scientists confirmed that water — in the form of ice — exists in the moon's polar regions.
Now, a new study confirms that water — not just hydroxyl — exists on sunlit surfaces of the moon.
💦🌚 Water molecules were found in Clavius Crater, one of the largest craters visible from Earth on the Moon! This di… https://t.co/LYvkYXSTf5— NASA (@NASA)1603733738.0
Publishing their findings in the journal Nature Astronomy on Monday, researchers examined the lunar surface using NASA's Stratospheric Observatory for Infrared Astronomy (SOFIA). This airborne observatory is mounted on a customized Boeing 747 that flies at an altitude of about 45,000 feet. That's high enough to rise above Earth's lower atmosphere, which contains water vapor that prevents land-based observatories from getting a clear view of the moon.
Using SOFIA, the team took a close look at two sites near, one near the lunar equator and another near the Clavius crater, one of the largest craters on the moon. The researchers observed light signals that could only have come from molecular water.
"We had indications that H2O – the familiar water we know – might be present on the sunlit side of the Moon," Paul Hertz, director of the Astrophysics Division in the Science Mission Directorate at NASA Headquarters in Washington, said in a statement. "Now we know it is there. This discovery challenges our understanding of the lunar surface and raises intriguing questions about resources relevant for deep space exploration."
SOFIA
Credits: NASA/Daniel Rutter
Still, it's not as if the moon is dripping wet. The observations suggest that a cubic meter of the lunar surface (in the Clavius crater site, at least) contains water in concentrations of 100 to 412 parts per million. That's roughly equivalent to a 12-ounce bottle of water. In comparison, the same plot of land in the Sahara desert contains about 100 times more water.
But a second study suggests other parts of the lunar surface also contain water — and potentially lots of it. Also publishing their findings in Nature Astronomy on Monday, the researchers used the Lunar Reconnaissance Orbiter to study "cold traps" near the moon's polar regions. These areas of the lunar surface are permanently covered in shadows. In fact, about 0.15 percent of the lunar surface is permanently shadowed, and it's here that water could remain frozen for millions of years.
Some of these permanently shadowed regions are huge, extending more than a kilometer wide. But others span just 1 cm. These smaller "micro cold traps" are much more abundant than previously thought, and they're spread out across more regions of the lunar surface, according to the new research.
Credit: dottedyeti via AdobeStock
Still, the second study didn't confirm that ice is embedded in micro cold traps. But if there is, it would mean that water would be much more accessible to astronauts, considering they wouldn't have to travel into deep, shadowy craters to extract water.
Greater accessibility to water would not only make it easier for astronauts to get drinking water, but could also enable them to generate rocket fuel and power.
"Water is a valuable resource, for both scientific purposes and for use by our explorers," said Jacob Bleacher, chief exploration scientist in the advanced exploration systems division for NASA's Human Exploration and Operations Mission Directorate, in a statement. "If we can use the resources at the Moon, then we can carry less water and more equipment to help enable new scientific discoveries."
