In addition to being the only solvent that is capable of supporting life, water is essential to life as we know it here on Earth. Because of this, finding deposits of water – whether in liquid form or as ice – on other planets is always exciting. Even where is not seen as a potential indication of life, the presence of water offers opportunities for exploration, scientific study, and even the creation of human outposts.
This has certainly been the case as far as the Moon and Mercury are concerned, where water ice was discovered in the permanently-shadowed cratered regions around the poles. But according to a new analysis of the data from the Lunar Reconnaissance Orbiter and the MESSENGER spacecraft, the Moon and Mercury may have significantly more water ice than previously thought.
The history of the Moon is a tale told by geology, apparent in its rocks, craters, and other surface features. For centuries, astronomers have studied the Moon from afar and for the past few decades, it has been visited by countless robotic missions. Between 1969 and 1972, a total of twelve astronauts walked on its surface, conducted lunar science, and brought samples of lunar rock back to Earth for study.
These efforts have taught us a lot about the things that have shaped the lunar surface, be they one-off events like the massive impact that formed the Shakleton crater to things that happened regularly throughout its 4.51 billion-year history. For instance, scientists recently discovered something unusual about the Antoniadi crater: a large boulder was perched on the rim of a smaller crater within after rolling about 1000 meters (1093 yards) downhill.
It’s always easier to show someone a picture of something rather than to use 1,000 words to explain it. The people at NASA’s Scientific Visualization Studio (SVS) know this, and they’re experts. Every year they release a simulation of the Moon that shows what the Moon will look like to us each day.
NASA’s Moon simulator uses images and data captured by the Lunar Reconnaissance Orbiter (LRO) to recreate the Moon on each hour of each day of each month in 2018. You can input any date and time to view the Moon (Dial-a-Moon) as it will appear at that time. You can also watch a video of the Moon over the course of the entire year. Along the way, you might learn something.
We often hear how the Moon’s appearance hasn’t changed in millions or even billions of years. While micrometeorites, cosmic rays and the solar wind slowly grind down lunar rocks, the Moon lacks erosional processes such as water, wind and lurching tectonic plates that can get the job done in a hurry.
Remember Buzz Aldrin’s photo of his boot print in the lunar regolith? It was thought the impression would last up to 2 million years. Now it seems that estimate may have to be revised based on photos taken by the Lunar Reconnaissance Orbiter (LRO) that reveal that impacts are transforming the surface much faster than previously thought.
The LRO’s high resolution camera, which can resolve features down to about 3 feet (1-meter) across, has been peering down at the Moon from orbit since 2009. Taking before and after images, called temporal pairs, scientists have identified 222 impact craters that formed over the past 7 years. The new craters range from 10 feet up to 141 feet (3-43 meters) in diameter.
By analyzing the number of new craters and their size, and the time between each temporal pair, a team of scientists from Arizona State University and Cornell estimated the current cratering rate on the Moon. The result, published in Nature this week, was unexpected: 33% more new craters with diameters of at least 30 feet (10 meters) were found than anticipated by previous cratering models.
Similar to the crater that appeared on March 17, 2013 (above), the team also found that new impacts are surrounded by light and dark reflectance patterns related to material ejected during crater formation. Many of the larger impact craters show up to four distinct bright or dark reflectance zones. Nearest to the impact site, there are usually zone of both high and low reflectance. These two zones likely formed as a layer of material that was ejected from the crater during the impact shot outward to about 2½ crater diameters from the rim.
From analyzing multiple impact sites, far flung ejecta patterns wrap around small obstacles like hills and crater rims, indicating the material was traveling nearly parallel to the ground. This kind of path is only possible if the material was ejected at very high speed around 10 miles per second or 36,000 miles per hour! The jet contains vaporized and molten rock that disturb the upper layer of lunar regolith, modifying its reflectance properties.
How LRO creates temporal pairs and scientists use them to discover changes on the moon’s surface.
In addition to discovering impact craters and their fascinating ejecta patterns, the scientists also observed a large number of small surface changes they call ‘splotches’ most likely caused by small, secondary impacts. Dense clusters of these splotches are found around new impact sites suggesting they may be secondary surface changes caused by material thrown out from a nearby primary impact. From 14,000 temporal pairs, the group identified over 47,000 splotches so far.
Based on estimates of size, depth and frequency of formation, the group estimated that the relentless churning caused by meteoroid impacts will turn over 99% of the lunar surface after about 81,000 years. Keep in mind, we’re talking about the upper regolith, not whole craters and mountain ranges. That’s more than 100 times faster than previous models that only took micrometeorites into account. Instead of millions of years for those astronaut boot prints and rover tracks to disappear, it now appears that they’ll be wiped clean in just tens of thousands!
Everyone on Earth is invited to join the celebration by hosting or attending an InOMN event — and uniting on one day each year to look at and learn about the Moon together. We encourage you to go to InOMN events near you, such as at your local planetariums or museums, or to go out and observe the moon yourself! You can find events near you at the InOMN site. You can also follow the InOMN Twitter feed to see what everyone is doing to celebrate!
Our friends over at CosmoQuest are proud to be partners in this celebration of Earth’s natural satellite. There you can “Observe the Moon” all year long by taking part in lunar-themed activities, such as our Moon Mappers citizen science program, where you’ll get to look at some of the most detailed images taken by the LRO, and help our scientists study the moon and it’s surface. This excellent program is available free of charge, no matter the weather, time of day or your location – you get the best views of the Moon ever!
Take some photos of your activities, whether outdoors observing or indoors mapping craters, and share them online at the CosmoQuest Twitter and Facebook feeds using the hashtag #observethemoon, and CosmoQuest will repost their favorites!
Here are just a few of the media celebrations that have already been posted for InOMN!
“The Moon and More” is a music video starring musicians Javier Colon (Season 1 winner of NBC’s “The Voice”), and Matt Cusson in collaboration with NASA’s Goddard Space Flight Center and the Lunar Reconnaissance Orbiter (LRO) mission.
Credits: NASA’s Goddard Space Flight Center/David Ladd, producer
For years, scientists have been hunting for the stable lava tubes that are believed to exist on the Moon. A remnant from the Moon’s past, when it was still volcanically active, these underground channels could very well be an ideal location for lunar colonies someday. Not only would their thick roofs provide naturally shielding from solar radiation, meteoric impacts, and extremes in temperature. They could also be pressurized to create a breathable environment.
But until now, evidence of their existence has been inferred from surface features such as sinuous rilles – channel-like depressions that run along the surface that indicate the presence of subterranean lava flows – and holes in the surface (aka. “skylights”). However, recent evidence presented at the 47th Lunar and Planetary Science Conference (LPSC) in Texas indicates that one such stable lava tube could exist in the once-active region known as Marius Hills.
NASA has just received a significant boost in the agency’s current budget after both chambers of Congress passed the $1.1 Trillion 2016 omnibus spending bill this morning, Friday, Dec. 18, which funds the US government through the remainder of Fiscal Year 2016.
Nearly 47 years ago, the crew of Apollo 8 took an image of planet Earth from the Moon that has been called “the most influential environmental photograph ever taken.” Called Earthrise, the picture represented the first time human eyes saw their homeworld come into view around another planetary body.
Wow, this doesn’t happen very often: Earth and Mars together in one photo. To make the image even more unique, it was taken from lunar orbit by the Lunar Reconnaissance Orbiter. This two-for-one photo was was acquired in a single shot on May 24, 2014, by the Narrow Angle Camera (NAC) on LRO as the spacecraft was turned to face the Earth, instead of its usual view of looking down at the Moon.
The LRO imaging team said seeing the planets together in one image makes the two worlds seem not so far apart, and that the Moon still might have a role to play in future exploration.
“The juxtaposition of Earth and Mars seen from the Moon is a poignant reminder that the Moon would make a convenient waypoint for explorers bound for the fourth planet and beyond!” said the LRO team on their website. “In the near-future, the Moon could serve as a test-bed for construction and resource utilization technologies. Longer-range plans may include the Moon as a resource depot or base of operations for interplanetary activities.”
Watch a video created from this image where it appears you are flying from the Earth to Mars:
The LROC team said this imaging sequence required a significant amount of planning, and that prior to the “conjunction” event, they took practice images of Mars to refine the timing and camera settings.
When the spacecraft captured this image, Earth was about 376,687 kilometers (234,062 miles) away from LRO and Mars was 112.5 million kilometers away. So, Mars was about 300 times farther from the Moon than the Earth.
The NAC is actually two cameras, and each NAC image is built from rows of pixels acquired one after another, and then the left and right images are stitched together to make a complete NAC pair. “If the spacecraft was not moving, the rows of pixels would image the same area over and over; it is the spacecraft motion, combined with fine-tuning of the camera exposure time, that enables the final image, such as this Earth-Mars view,” the LRO team explained.
Check out more about this image on the LRO website, which includes a zoomable, interactive version of the photo.
NASA’s planetary senior review panel harshly criticized the scientific return of the Curiosity rover in a report released yesterday (Sept. 3), saying the mission lacks focus and the team is taking actions that show they think the $2.5-billion mission is “too big to fail.”
While the review did recommend the mission receive more funding — along with the other six NASA extended planetary missions being scrutinized — members recommended making several changes to the mission. One of them would be reducing the distance that Curiosity drives in favor of doing more detailed investigations when it stops.
The role of the senior review, which is held every two years, is to help NASA decide what money should be allocated to its extended missions. This is important, because the agency (as with many other departments) has limited funds and tries to seek a balance between spending money on new missions and keeping older ones going strong.
Engineering acumen means that many missions are now operating well past their expiry dates, such as the Cassini orbiter at Saturn and the Opportunity rover on Mars. In examining the seven missions being reviewed, the panel did recommend keeping funding for all, but said that 4/7 are facing significant problems.
In the case of Curiosity, the panel called out principal investigator John Grotzinger for not showing up in person on two occasions, preferring instead to interact by phone. The review also said there is a “lack of science” in its extended mission proposal with regard to “scientific questions to be answered, testable hypotheses, and proposed measurements and assessment of uncertainties and limitations.”
Other concerns were the small number of samples over the prime and extended missions (13, a “poor science return”), and a lack of clarity on how the ChemCam and Mastcam instruments will play into the extended mission. Additionally, the panel expressed concern that NASA would cut short its observations of clays (which could help answer questions of habitability) in favor of heading to Mount Sharp, the mission’s ultimate science destination.
“In summary, the Curiosity … proposal lacked scientific focus and detail,” the panel concluded, adding in its general recommendations for the reviews that principal investigators must be present to avoid confusion while answering questions. The other missions facing concern from the panel included the Lunar Reconnaissance Orbiter, Mars Express and Mars Odyssey.
LRO: Its extended mission (the second) is supposed to look at how the moon’s surface, subsurface and exosphere changes through processes such as meteorites and interaction with space. The panel was concerned with a “lack of detail” in the proposal and in answers to follow-up questions. The panel also recommended turning off certain instruments “at the end of their useful science mission”.
Mars Express: The extended mission is focusing on the ionosphere and atmosphere as well as the planet’s surface and subsurface. Concerns were raised about matters such as why funding is needed to calibrate its high-resolution stereo camera after 11 years — especially given the instrument has been rarely cited in published journal reports lately — and how people involved in the extended mission would meet the goals. The panel also saw a “lack of communication” in the team.
Mars Odyssey: If approved, the spacecraft will move to the day/night line of Mars to look at the planet’s radiation, gamma rays, distribution of water/carbon dioxide/dust in the atmosphere, and the planet’s surface. The panel, however, said there are no “convincing arguments” as to how the new science relates to the Decadal Survey objectives for planetary science. Odyssey, which is in its 11th year, may also be nearing the end of its productive lifespan given fewer publications using its data in recent years, the panel said.
The panel also weighed in on the success of the Cassini and Opportunity missions:
Cassini received the highest rating — “Excellent” — due to its scientific merit, the only mission this time around to do so. The panel was particularly excited about seasonal changes that will be seen on Titan in the coming years, as well as measurements of Saturn’s rings and magnetosphere and its icier moons (such as Enceladus). The spacecraft is noted to be in good condition and the new mission will be a success because of “the unique aspect of the new observations.”
Opportunity, which is more than 10 years into its Mars exploration, is still “in sufficiently good condition” to do science, although the panel raised concerns about software and communication problems. The panel, however, said more time with the rover would allow it to look for evidence of past water on Mars that would not be visible from orbit — even though it’s unclear if phyllosilicates around its current location (Endeavour crater) are from the Noachian period, the earliest period in Mars’ history.
The panel is just one step along the road to figuring out how NASA chooses to spend its money in the coming years. Funding availability depends on how much money Congress allocates to the agency.