You have undoubtedly seen the moon, but have you ever seen it up close in glorious 4K resolution? Probably not, but you can see it right now on YouTube. NASA has uploaded a new video, created mostly from the Lunar Reconnaissance Orbiter (LRO) observations. The video takes you on a tour of several different regions, some of which still present tantalizing mysteries for future exploration.
The LRO has been orbiting the moon since 2009, sending back the highest quality images we’ve ever had of the lunar surface. The spacecraft’s main imaging device consists of several different cameras, all of which have contributed to the new video. There are two narrow-angle cameras that can capture images a 0.5-meter scale across a 3.1 mile (5 kilometers) swath of the surface. The wide-angle camera can capture 100-meter scale images in seven color bands across a 37.2 mile (60 kilometers) area.
The new 4K video takes you on a virtual tour of some of the most interesting areas of the moon. It might be a lifeless chunk of rock, but that doesn’t mean it can’t also be fascinating. For example, there’s the Orientale Basin, a giant preserved impact crater the size of Texas. The video includes topographic data from LRO and gravity measurements from the GRAIL spacecraft. The Orientale Basin might be big, but it’s not the biggest crater on the moon. That honor goes to the South Pole-Aitken Basin featured later in the video. It’s hiding over on the dark side of the moon, with a diameter of more than 1,300 miles (2,200 kilometers).
On the near side of the moon is a smaller crater called Tycho — it’s one of the most famous structures on the moon. You can see the crater structure in astounding detail thanks to the LRO data. It’s only 100 million years old, so the central peak is still quite visible. There’s also a strange boulder in the center, the origin of which is still unknown.
The video also includes high-resolution images of the Apollo 17 landing site in the Taurus-Littrow valley. The resolution is so high, you can make out the tracks left by the rover. The lander’s platform is still sitting there as well.
The data used to make this video is the same data NASA will rely upon as it plans future lunar surface exploration, possibly including manned missions. NASA has a Tumblr post with details on all the sites covered in the video. In other news, NASA has a Tumblr page. Who knew?
“Because water is such a vital ingredient for life, we rightly see it as precious,” said Richard Greenwood of Open University, a distance learning and research university located in England. “Our research shows that water is also extremely resilient and can survive an event as catastrophic as two planets colliding.”
There has long been a debate over how — and when — Earth obtained the water that is ubiquitous on our world today. While water molecules were part of the cloud of gas and dust that coalesced into our solar system 4.6 billion years ago, Earth’s early history included scorching temperatures and little-to-no atmosphere, so it was thought that any water on the planet’s surface would likely have evaporated.
There is also the prevailing theory that the moon was formed from a cataclysmic collision between proto-Earth and a solid impactor about 100 million years after our solar system’s formation. This giant impact, some scientists have proposed, surely would have blasted Earth’s water away.
That led many scientists to suggest that water would have been introduced on Earth at a later time, when it was pummeled by comets and asteroids during the Late Heavy Bombardment period, 4.1 to 3.8 billion years ago. Several studies suggest that these objects could have readily supplied the amount of water that is present on Earth today.
One sticking point for the giant impact theory, however, is planets in our solar system have unique chemical makeups. Earth and our moon appear similar when it comes to versions of elements called isotopes — specifically different isotopes of oxygen. A previous study discovered, though, that some rocks from the Apollo missions contained slightly more oxygen-17 than oxygen-16 when compared to Earth rocks. That indicated that the moon might have been primarily formed from the impactor rather than the proto-Earth.
But the new study not only supports the giant impact theory of the moon’s formation, it says Earth’s water could have survived such an event. The study also clarifies differences and similarities between the Earth and the moon.
Greenwood and his colleagues compared the oxygen composition from both Earth rocks and lunar samples brought back by the Apollo astronauts. In analyzing the oxygen-isotope compositions in both sets of samples, they showed a very small 3 to 4 parts per million difference between the two. There was “no significant difference” between the lunar samples and Earth samples in the amount of olivine, a common mineral in Earth’s subsurface.
According to the authors, these findings are consistent with high-energy impact simulations that confirm an almost complete “mixing” of the proto-Earth and the impactor, as well as retention of a large amount of water on Earth, as much as 70-95 percent.
“On the basis of this assumption, our data indicates that post-giant impact additions to the Earth could have contributed between 5 and 30 percent of Earth’s water, depending on global water estimates,” the team wrote. “Consequently, our data indicate that the main fraction of Earth’s water was accreted before the giant impact and not later, as often proposed.”
Greenwood and his team say their findings could potentially have implications for exoplanet habitability. Studies of extrasolar planetary systems have shown that many distant systems likely experienced similar chaotic collisions early in their formation, too, which led to doubts about the amount of liquid water on some of these worlds.
“What’s even more fascinating is that, because this worked for the Earth and the moon, it must also work for planets beyond our solar system,” Greenwood said in a statement. “Exoplanets with water on their surfaces may be much more common than we previously thought. And where there’s water, there could also be life!”
In case you hadn’t noticed, Mars is a pretty big deal these days. The Red Planet is our most similar neighbor and, unlike any other planet in our Solar System, we’ve explored a large chunk of it with multiple landers and rovers. It will almost certainly be the first planet that humans set foot on (besides Earth of course) and it may very well happen within our lifetimes. That being said, there’s still a ton we don’t know about the planet, and more specifically what its insides look like. Next year, we’ll get our first glimpse.
NASA’s InSight lander is slated to launch in just over a month, and once it completes its long journey to Mars it will be the first piece of NASA hardware to send back data on the interior makeup of the planet. It promises to be a mission of many “firsts,” and NASA just released a nice, in-depth rundown of what InSight will do.
InSight — which stands for Interior Exploration using Seismic Investigations, in case you were wondering — is equipped with sensitive seismometers that will detect vibrations from within Mars. These “marsquakes” are incredibly important to InSight’s research because it will help paint a picture of what lies beneath the surface.
“A seismometer is like a camera that takes an image of a planet’s interior,” Bruce Banerdt of NASA’s Jet Propulsion Laboratory, and principal investigator of InSight explains. “It’s a bit like taking a CT scan of a planet.”
So what will that “CT Scan” reveal? Scientists aren’t totally sure. As the lander gathers more and more information over time, thanks to continued quaking and even the impacts of other objects on the Martian surface, the “snapshot” of its insides will grow more and more clear. Ultimately, the team hopes to be able to explain the layers that make up the planet and break them down in the same way that we understand the layers of Earth.
As the universe’s only known harbor for life, Earth is arguably one strange rock. But light-years from our solar system, other intelligent beings on a similar planetary oasis might be gazing in our direction and seeing us as a sign that they’re not alone in the universe.
To date, astronomers have confirmed the existence of nearly 4,000 planets beyond our solar system, including some that just might have the conditions necessary to support life as we know it. As our technology improves, we should be able to learn more about these worlds and their chances of hosting plants, animals, and maybe even civilizations.
That means if aliens are out there, they could just as easily discover us.
First, they’d need to find Earth from afar, either by watching our sun wobble as the planet’s gravity tugs against it, or by seeing the sun dim as Earth blocks a tiny fraction of sunlight during its orbit. Nine known alien worlds can see Earth transit across our sun, just as we’ve seen thousands of alien planets dim their host stars.
Once spotted, our planet would likely intrigue E.T. Our sun is relatively stable, not prone to disastrous flares that’d rip our atmosphere to shreds. What’s more, we fall squarely within our sun’s habitable zone, the area around a star where liquid water can persist on a planet’s surface. (These are just some of the things that make life as we know it possible on Earth.)
Faraway scientists might then attempt to spot our atmosphere, to see whether life’s thumb is on the chemical scales. But what would they be looking for? And could they really infer life’s presence across trillions of miles?
Oxygen is a highly reactive element, glomming on to other atoms and molecules with such alacrity that it’s tough to find it in abundance by itself—unless something is breaking down oxygen-rich compounds and pumping out loads of O2. On Earth, you can thank photosynthetic plants for being generous oxygen factories.
But oxygen alone wouldn’t be enough for E.T. to prove our existence. “We have discovered several ways in which O2 can accumulate in the absence of life,” says Stephanie Olson, an astrobiologist at the University of California, Riverside. “High levels of O2, or the processes culminating in high levels of O2, may actually preclude the emergence of life on some planets.”
In addition to oxygen molecules, alien astronomers would look at our atmosphere’s levels of nitrogen, carbon dioxide, nitrous oxide, and methane. Only life could keep Earth chemically off-kilter enough for all these gases to persist at once.
Beyond those chemical clues, alien astronomers with truly massive telescopes might even be able to map Earth’s surface from afar, down to major urban areas.
As a proof-of-concept for this telescope, called the ExoLife Finder, or ELF, Berdyugina and Kuhn simulated how nearby aliens using the telescope would see Earth. From 25 trillion miles away, E.T. could not only map Earth’s continents, but they’d also be able to see signs of intelligent life.
“The ELF telescope has the sensitivity to see a Los Angeles basin,” says Kuhn. “We don’t see the lights, but we see the heat signature.” Their group, the Planets Foundation, is now building a single-mirror telescope in Hawaii to test the underlying tech. If all goes to plan, they say it’s possible to build ELF within a decade.
“It would be like Star Trek, the reality show,” says Berdyugina. “We could virtually visit these planets.”
If intelligent life is nearby, the most straightforward way to find earthlings would be to listen for us. For the last century, human civilization has been broadcasting its existence to the cosmos via our leaky radio transmissions. Occasionally, we’ve broadcast messages to E.T. intentionally, and sent golden records into the void on the off-chance that aliens stumble across our interplanetary spacecraft.
Aliens wouldn’t be able to detect our radio presence, much less our golden records, unless they’re within 590 trillion miles of Earth. If intelligent life is any farther away than that, our earliest radio signals simply haven’t reached them yet.
But in several centuries’ time, intelligent aliens may see other signs of our tech-savviness. In a study recently accepted to The Astrophysical Journal, for example, astrophysicist Hector Socas-Navarro says we could find intelligent life by looking for artificial satellites orbiting alien worlds. And that means they could find us using similar methods.
As a satellite-fringed world drifts in front of its home star, its satellites would block some starlight in front of and behind the transiting planet. This metallic belt would look unnatural when compared to known planetary rings.
Currently, Earth’s satellite network isn’t anywhere near dense enough to be detected, nor will it be anytime soon. But our footprint in space is growing exponentially: If we keep launching satellites at our present pace, Socas-Navarro says in his study, nearby aliens armed with telescopes as powerful as the ones we have today could spot our satellites by 2200.
Winds of Change
Of course, Earth is more than 4.5 billion years old, and life has changed a lot over the eons. What if alien astronomers had looked our way even a billion years ago?
In a 2018 paper in Science Advances, Olson and her colleagues simulated how Earth’s atmosphere has changed over time. Even three billion years ago, aliens may have been able to infer life by sniffing out methane and carbon dioxide in the early atmosphere. But our modern atmosphere—a literal beacon for life—arrived only about 500 million years ago.
“For more than a billion years of Earth history, an alien astronomer may have even been sufficiently misled to conclude that Earth was sterile—despite the fact that life was flourishing in our ocean at the time,” says Olson.
Still, if the aliens were advanced and committed enough, even an early Earth would yield compelling clues for life, says study coauthor Joshua Krissansen-Totton of the University of Washington.
“The presence of life on Earth has been fairly obvious for the last 4 billion years to anyone who could build a big telescope,” he says in an email. “If there was anything nasty out there, then they would have extinguished life on Earth long ago. I think we are safe inviting them over to visit and exchange notes on the cosmos.”
If aliens are anything like us, perhaps the news that they aren’t alone in the cosmos wouldn’t be their equivalent of earth-shattering. In a study published in Frontiers in Psychology in February, researchers found that people, at least, would take the discovery of alien life in stride.
“People will be able to accommodate even high-impact scientific discoveries without their worldviews collapsing,” theologian Ted Peters said at the time.
But like us, aliens may fear the prospect of hostile, intelligent extraterrestrials—in this case, humans—arriving unannounced on their cosmic doorstep.
The model uses a number of different sources of data to predict the possibility of landslides in any part of the world.
A new modeling system created by NASA researchers is the first of its kind to allow scientists to predict the risk of landslide activity in any part of the world in “near real-time.”
As detailed in a news release from NASA, the space agency developed the prediction model at its Goddard Space Flight Center. The system uses rainfall, which was described as the leading cause of landslides around the world, as the main variable that could point to the risk of such events taking place. Should conditions below the surface in a certain area be considered unstable, massive rainfall could potentially serve as a catalyst of landslide activity, resulting in a combination of rocks, mud, and/or debris tumbling down hills and mountains.
“Landslides can cause widespread destruction and fatalities, but we really don’t have a complete sense of where and when landslides may be happening to inform disaster response and mitigation,” said Goddard landslide expert Dalia Kirschbaum, who co-authored a paper published in the journal Earth’s Future detailing the new model and how it works.
“This model helps pinpoint the time, location and severity of potential landslide hazards in near real-time all over the globe. Nothing has been done like this before.”
A report from UPIsummarized the methodologies used by the Goddard Space Flight Center when it created the new model, stating that the system blends data gathered from satellite images and predictive analytics to come up with its near real-time predictions. In order to analyze historical landslide activity in a given area, the model makes use of machine learning techniques, while NASA and Japan Aerospace Exploration Agency (JAXA) satellites provide the required rainfall data, almost in real-time, allowing for the most updated and relevant risk data available.
In addition to the above data, the model also uses a global susceptibility map in the event that precipitation levels are “unusually high” in a given area. According to NASA’s news release, the map takes five variables into account, all of which are important in predicting the possibility of landslide activity — the presence of nearby roads, trees having been burned or removed, the proximity of a “major” tectonic fault, weak bedrock in the area, and steep hillsides. If, based on these five variables, the model points to a location with heavy rainfall as being vulnerable, it then produces a “nowcast” that warns of high or moderate chances of a landslide taking place. New notifications are sent out every 30 minutes thereafter.
In a statement, study co-author and Goddard landslide expert Thomas Stanley said that the new model has the potential to help scientists understand the risks of imminent landslides “in a matter of minutes.” Given that the model also proved to be effective in analyzing trends when the new data was compared to historical information, he added that it could be the first of its kind used to provide a retroactive snapshot of landslide activity over a certain period of time.