Galaxies may grow by swiping gas from their neighbors.

New simulations suggest that nearly half the matter in the Milky Way may have been siphoned from the gas of other galaxies. That gas provides the raw material that galaxies use to build their bulk. The finding, scheduled to appear in the Monthly Notices of the Royal Astronomical Society, reveals a new, unexpected way for galaxies to acquire matter and could give clues to how they evolve.
“These simulations show a huge amount of interaction among galaxies, a huge dance that’s going on,” says astronomer Romeel Davé of the University of Edinburgh. That dance, and the subsequent exchange of atoms, could be what establishes a galaxy’s character — whether it’s small or big, elliptical or spiral, quiet or bursting with star formation. If the simulation results are confirmed with observations, it could be a major advancement in understanding galaxy formation, Davé says.

It makes sense that much of the material in one galaxy actually came from other galaxies, says study coauthor Claude-André Faucher-Giguère, a theoretical astrophysicist at Northwestern University in Evanston, Ill. “Still, the result was really unexpected,” he says.

Astronomers thought galaxies got their matter in two main ways. First, atoms clumped together to form stars and then galaxies, not long after the Big Bang about 13.8 billion years ago. Then some of those atoms were eventually ejected by supernovas but rained back onto the same galaxy, recycling the gas again and again.

The new simulations showed a third way galaxies could score gas. Powerful supernova explosions would eject atoms, in the form of gas, far from their home galaxies into intergalactic space. Those atoms would then travel through space, pushed toward other galaxies by galactic winds that move at several hundred kilometers per second. When the particles neared a galaxy’s gravitational pull, they would get sucked in, where they would serve as the basis for stars, planets, dust and other material in their new galactic home. Still, this exchange of atoms is extremely difficult to spot in space because the gas atoms, don’t give off light like stars do.
Faucher-Giguère and colleagues spotted the exchange in computer simulations that show how galaxies formed just after the Big Bang and how they have evolved over time. The team tracked gas atoms as they moved through the model universe, formed stars and then were ejected from galaxies as those stars exploded.

In the simulations, up to half of the atoms in large galaxies were pulled in from other galaxies. Because more massive galaxies have more gravity, they tended to pull atoms from the ejected material of small galaxies. The exchange appears to take billions of years as atoms travel the vast space between galaxies, the team notes.

“It’s that not surprising to see a galaxy kick out matter, which is then pulled in by other galaxies,” Davé says. What is surprising, he says, is the amount of material that’s transferred. Before seeing the simulations, he would have guessed that about 5 percent of gas was transferred among galaxies this way. “To see that it is up to 50 percent is pretty remarkable,” he says.

Already, astronomers are searching for evidence of this material-swapping behavior among galaxies. Faucher-Giguère and colleagues, working with researchers using the Hubble Space Telescope, hope to observe intergalactic transfer of gas among galaxies soon.

The largest marsupial to ever walk the Earth just got another accolade: It’s also the only marsupial known to migrate seasonally.

Diprotodon optatum was a massive wombat-like herbivore that lived in what’s now Australia and New Guinea during the Pleistocene, until about 40,000 years ago. Now, an analysis of one animal’s teeth suggests that it undertook long, seasonal migrations like those made by zebras and wildebeests in Africa.

Animals pick up the chemical element strontium through their diet, and it leaves a record in their teeth. The ratio of different strontium isotopes varies from place to place, so it can provide clues about where an animal lived. Strontium isotope ratios in an incisor from one D. optatum revealed a repeating pattern. That suggests the animal migrated seasonally — it moved around, but generally hit up the same rest stops each year, researchers report September 27 in the Proceedings of the Royal Society B.

It’s the first evidence to show a marsupial — living or extinct — migrating in this way, says study coauthor Gilbert Price, a paleoecologist at the University of Queensland in Brisbane, Australia. It’s not clear exactly why this mega-marsupial might have migrated, but an analysis of the carbon isotopes in its teeth suggests it ate a fairly limited diet. So it might have migrated to follow food sources that popped up seasonally in different places, the authors suggest.

Pluto has no rings — New Horizons triple-checked. An exhaustive search for rings and dust particles around the dwarf planet before, during and after the spacecraft flew past Pluto in 2015 has come up empty.

“It’s a very long paper to say we didn’t find anything,” says team member Tod Lauer of the analysis, posted online September 23 at arXiv.org. But the nonresult could help scientists understand the contents of the outer solar system — and help plan New Horizons’ next encounter. The spacecraft is now on a course to a space rock in the Kuiper Belt, another 1.5 billion kilometers past Pluto.
Before New Horizons arrived at Pluto, the possible existence of rings was an urgent matter of safety. Hitting a particle as small as a sand grain could have damaged the spacecraft.

Searches with the Hubble Space Telescope in 2011 and 2012 turned up two previously unknown moons orbiting Pluto — Kerberos and Styx (SN: 11/28/15, p. 14) — and zero rings. Even so, many researchers expected to encounter rings, or at least some debris. The four outer planets in the solar system have rings, as do other small bodies in the solar system, like the tiny planetoid 10199 Chariklo (SN: 5/3/14, p. 10). And some studies suggest that Pluto probably had rings at one point in its past, left over from the collision that formed its largest moon, Charon.

Nine weeks before New Horizons’ closest approach to Pluto, a team jokingly called the “crow’s nest” acted much like a ship’s lookout for potential hazards, says Lauer, an astronomer with the National Optical Astronomy Observatory in Tucson, Ariz. The group examined images taken with the spacecraft’s Long Range Reconnaissance Imager camera, looking for ring particles reflecting sunlight or spots that moved against a starry background from one set of images to the next. Nothing turned up.

The team declared the spacecraft’s trajectory safe, and New Horizons flew sailed safely past Pluto on July 14, 2015 (SN Online: 7/15/15). After the flyby, the team turned New Horizons around to look back at Pluto, and towards the sun. This was a much better position to look for rings, as dust particles would pop into view when backlit by the sun like motes of dust in the light from a window.

“If you really want to know for sure whether there’s any dust there, the viewing geometries where you’re looking past the dust with the sun in the background, that’s the gold standard,” says Matthew Tiscareno of the SETI Institute in Mountain View, Calif., who studied Saturn’s rings with the Cassini spacecraft but was not involved in New Horizons.
It took the better part of a year for all the data from New Horizons to return to Earth, and several months after that to analyze it, but the team is now ready to call it: The rings really aren’t there — or at least they’re too diffuse to see.

That’s somewhat surprising, Lauer says. But the chaotic gravity of Pluto’s family of moons might make it too hard for rings to find stable orbits. Or the slight pressure generated by light particles streaming from the sun could constantly blow would-be ring particles away.

It’s also possible there just wasn’t that much dust there to begin with. New Horizons saw fewer craters on Pluto and Charon than expected, which could mean there are fewer small bodies at that distance from the sun smacking into Pluto and its moons and kicking up dust.

That could be good news for New Horizons’ next act. After five months in hibernation, the spacecraft woke up on September 11 and has set its sights on a smaller, weirder and more distant object: a space rock about 30 kilometers long called 2014 MU69 (SN Online: 7/20/17). Initial observations suggest it might be a double object, with two bodies orbiting closely or touching lightly.

New Horizons will fly past MU69 on January 1, 2019. In the meantime, the team is looking for hazards along the route. “We’re going to do a similar effort to what we did with Pluto,” Lauer says. “We’re going to get in the crow’s nest and get out our binoculars, as it were, and see if we’re going to be okay.”

What looks like a spider, but with a segmented rear plus a long spike of a tail, has turned up in amber that’s about 100 million years old.

Roughly the size of a peppercorn (not including the tail, which stretches several times the body length), this newly described extinct species lived in forests in what is now Myanmar during the dinosaur-rich Cretaceous Period.

Spiders as their own distinctive group had evolved long before. Whether this tailed creature should be considered a true spider (of the group Araneae) is debatable though, researchers acknowledge February 5 in two studies in Nature Ecology & Evolution. In one of the papers, the fossils’ chimeric mash-up of traits both spidery and nonspidery inspired Bo Wang of the Chinese Academy of Sciences in Nanjing and colleagues to name the species Chimerarachne yingi.
C. yingi indeed has some anatomy that, among living animals, would be unique to spiders, says Gonzalo Giribet of Harvard University, a coauthor of the other paper. The fossils have what look like little structures that could have exuded spider silk, as well as distinctive male spider sex organs. Called pedipalps, these modified legs have no direct connection to a sperm-producing organ. Spiders need to load them before mating, for instance by ejaculating a sperm droplet and dipping pedipalps in it, so the structures can deliver the sperm a bit like a syringe.

But the abdomen-like end of a true spider’s body isn’t segmented and certainly doesn’t have a tail. Giribet and his colleagues’ analysis puts C. yingi in an ancient sister group of spiders. That’s startling in itself, Giribet says, because researchers have speculated that this Uraraneida group had gone extinct much earlier. So, spider or not, C. yingi remains intriguing.

Underwater grasses are growing back in the Chesapeake Bay. The plants now carpet three times as much real estate as in 1984, thanks to more than 30 years of efforts to reduce nitrogen pollution. This environmental success story shows that regulations put in place to protect the bay’s health have made a difference, researchers report the week of March 5 in Proceedings of the National Academy of Sciences.

Rules limiting nutrient runoff from farms and wastewater treatment plants helped to decrease nitrogen concentrations in the bay by 23 percent since 1984. That decline in nitrogen has allowed the recovery of 17,000 hectares of grasses, the new study shows — enough to cover roughly 32,000 football fields.
“This is one of the best examples we have of linking long-term research data with management to show how important that is in restoring this critical habitat,” says Karen McGlathery, an environmental scientist at the University of Virginia in Charlottesville who wasn’t involved in the research. ”I don’t know of any other system that’s so large and so complicated where these connections have been made.”

The bay’s aquatic vegetation, including seagrasses and freshwater grasses, is an important part of coastal ecosystems, says study coauthor Jonathan Lefcheck, a marine ecologist at the Bigelow Laboratory for Ocean Sciences in East Boothbay, Maine. Beds of underwater grasses act as nurseries that shelter young fish and aquatic invertebrates. The plants clean the water by trapping particulates, and stabilize shorelines by preventing erosion. But the once-lush grasses began dying off in the 1950s when the region’s human population boomed, and cities and farms dumped increasing amounts of nitrogen and other nutrients into the bay.

In the late 1970s and early 1980s, state and federal agencies took action, limiting the amount of nutrients that could enter the bay from farms, water treatment facilities and other sources. Those groups also instituted programs to monitor the bay’s health, building up the stockpile of information that Lefcheck and his colleagues have now analyzed.

The researchers looked at aerial surveys of the bay, data on water temperature and nutrient levels, as well as land and fertilizer use. Using mathematical equations to test which variables had the biggest impact on seagrass regrowth, the team pinned down nitrogen reduction as the driving force. That makes sense: Too much nitrogen in water promotes the growth of plankton, which can block sunlight, and algae, which can settle on the grass blades and smother them.
Now, though, researchers are seeing just the opposite. Grasses need clean water to get a foothold, but once they settle in, they “modify their own environment and make it better,” Lefcheck says. “Once you get a little bit established, it can take off.”

As I’ve been reporting a story about the opioid epidemic, I’ve sorted through a lot of tragic numbers that make the astronomical spike in deaths and injuries related to the drugs feel more real.

The rise in the abuse of opioids — powerfully addictive painkillers — is driven by adults. But kids are also swept up in the current, a new study makes clear. The number of children admitted to pediatric intensive care units at hospitals for opioid-related trouble nearly doubled between 2004 and 2015, researchers report in the March Pediatrics.
Researchers combed through medical records from 46 hospitals around the United States, looking for opioid-related reasons for admission to the hospital. When the researchers looked at children who landed in pediatric intensive care units for opioid-related crises, the numbers were grim, nearly doubling. In the period including 2004 to 2007, 367 children landed in the PICU for opioid-related trouble. In the period including 2012 to 2015, that number was 643. (From 2008 to 2011, 554 kids were admitted to the PICU for opioid-related illnesses.)
Most opioid-related hospital admissions were for children ages 12 to 17, the researchers found. The available stats couldn’t say how many of those events were accidental ingestions versus intentional drug use. (Though for older kids, there’s a sliver of good news from elsewhere: Prescription opioid use among teenagers is actually down, a recent survey suggests.)
But about a third of the hospitalizations were for children younger than 6. And among these young kids, about 20 percent of the poisonings involved methadone, a drug that’s used to treat opioid addiction. That means that these young kids are getting into adults’ drugs (illicit or prescribed) and accidentally ingesting them.

Lots of parents don’t store their prescription opioid painkillers safely away from their young children, a survey last year suggests. Drugs, prescription or otherwise, should be kept out of sight and out of reach, ideally locked away. Some kids are great climbers, and some are crafty bottle openers who can, with persistence, work around supposedly child-resistant packaging.

These are tips for everyone living with small kids — not just those who may have opioids in the house. Children are curious, persistent and, sadly, extra vulnerable to powerful drugs, which means that we should all do our best to keep them away from these potentially dangerous drugs.

A genetic hack to make photosynthesis more efficient could be a boon for agricultural production, at least for some plants.

This feat of genetic engineering simplifies a complex, energy-expensive operation that many plants must perform during photosynthesis known as photorespiration. In field tests, genetically modifying tobacco in this way increased plant growth by over 40 percent. If it produces similar results in other crops, that could help farmers meet the food demands of a growing global population, researchers report in the Jan. 4 Science.
Streamlining photorespiration is “a great step forward in efforts to enhance photosynthesis,” says Spencer Whitney, a plant biochemist at Australian National University in Canberra not involved in the work.

Now that the agricultural industry has mostly optimized the use of yield-boosting tools like pesticides, fertilizers and irrigation, researchers are trying to micromanage and improve plant growth by designing ways to make photosynthesis more efficient (SN: 12/24/16, p. 6).

Photorespiration is a major roadblock to achieving such efficiency. It occurs in many plants, such as soybeans, rice and wheat, when an enzyme called Rubisco — whose main job is to help transform carbon dioxide from the atmosphere into sugars that fuel plant growth — accidentally snatches an oxygen molecule out of the atmosphere instead.

That Rubisco-oxygen interaction, which happens about 20 percent of the time, generates the toxic compound glycolate, which a plant must recycle into useful molecules through photorespiration. This process comprises a long chain of chemical reactions that span four compartments in a plant cell. All told, completing a cycle of photorespiration is like driving from Maine to Florida by way of California. That waste of energy can cut crop yields by 20 to 50 percent, depending on plant species and environmental conditions.Streamlining photorespiration is “a great step forward in efforts to enhance photosynthesis,” says Spencer Whitney, a plant biochemist at Australian National University in Canberra not involved in the work.

Now that the agricultural industry has mostly optimized the use of yield-boosting tools like pesticides, fertilizers and irrigation, researchers are trying to micromanage and improve plant growth by designing ways to make photosynthesis more efficient (SN: 12/24/16, p. 6).

Photorespiration is a major roadblock to achieving such efficiency. It occurs in many plants, such as soybeans, rice and wheat, when an enzyme called Rubisco — whose main job is to help transform carbon dioxide from the atmosphere into sugars that fuel plant growth — accidentally snatches an oxygen molecule out of the atmosphere instead.

That Rubisco-oxygen interaction, which happens about 20 percent of the time, generates the toxic compound glycolate, which a plant must recycle into useful molecules through photorespiration. This process comprises a long chain of chemical reactions that span four compartments in a plant cell. All told, completing a cycle of photorespiration is like driving from Maine to Florida by way of California. That waste of energy can cut crop yields by 20 to 50 percent, depending on plant species and environmental conditions.
Using genetic engineering, researchers have now designed a more direct chemical pathway for photorespiration that is confined to a single cell compartment — the cellular equivalent of a Maine-to-Florida road trip straight down the East Coast.

Paul South, a molecular biologist with the U.S. Department of Agriculture in Urbana, Ill., and colleagues embedded genetic directions for this shortcut, written on pieces of algae and pumpkin DNA, in tobacco plant cells. The researchers also genetically engineered the cells to not produce a chemical that allows glycolate to travel between cell compartments to prevent the glycolate from taking its normal route through the cell.
Unlike previous experiments with human-designed photorespiration pathways, South’s team tested its photorespiration detour in plants grown in fields under real-world farming conditions. Genetically altered tobacco produced 41 percent more biomass than tobacco that hadn’t been modified.
“It’s very exciting” to see how well this genetic tweak worked in tobacco, says Veronica Maurino, a plant physiologist at Heinrich Heine University Düsseldorf in Germany not involved in the research, but “you can’t say, ‘It’s functioning. Now it will function everywhere.’”

Experiments with different types of plants will reveal whether this photorespiration fix creates the same benefits for other crops as it does for tobacco. South’s team is currently running greenhouse experiments on potatoes with the new set of genetic modifications, and plans to do similar tests with soybeans, black-eyed peas and rice.

The vetting process for such genetic modifications to be approved for use on commercial farms, including more field testing, will probably take at least another five to 10 years, says Andreas Weber, a plant biochemist also at Heinrich Heine University Düsseldorf who coauthored a commentary on the study that appears in the same issue of Science. In the meantime, he expects that researchers will continue trying to design even more efficient photorespiration shortcuts, but South’s team “has now set a pretty high bar.”

THE WOODLANDS, Texas — Grains of dust from the edge of the solar system could be finding their way to Earth. And NASA may already have a handful of the debris, researchers report.

With an estimated 40,000 tons of space dust settling in Earth’s stratosphere every year, the U.S. space agency has been flying balloon and aircraft missions since the 1970s to collect samples. The particles, which can be just a few tens of micrometers wide, have long been thought to come mostly from comets and asteroids closer to the sun than Jupiter (SN Online: 3/19/19).

But it turns out that some of the particles may have come from the Kuiper Belt, a distant region of icy objects orbiting beyond Neptune, NASA planetary scientist Lindsay Keller said March 21 at the Lunar and Planetary Science Conference. Studying those particles could reveal what distant, mysterious objects in the Kuiper Belt are made of, and perhaps how they formed (SN Online: 3/18/19).

“We’re not going to get a mission out to a Kuiper Belt object to actually collect [dust] samples anytime soon,” Keller said. “But we have samples of these things in the stratospheric dust collections here at NASA.”
One way to find a dust grain’s home is to probe the particle for microscopic tracks where heavy charged particles from solar flares punched through. The more tracks a grain has, the longer it has wandered in space — and the more likely it originated far from Earth, says Keller, who works at the Johnson Space Center in Houston.

But to determine precisely how long a dust grain has spent traveling space, Keller first needed to know how many tracks a grain typically picks up per year. Measuring that rate required a sample with a known age and known track density — criteria met only by moon rocks brought back on the Apollo missions. But the last track-rate estimate was done in 1975 and with less precise instruments than are available today.
So Keller and planetary scientist George Flynn of SUNY Plattsburgh reexamined that same Apollo rock with a modern electron microscope. They found that the rate at which rocks pick up flare tracks was about 20 times lower than the previous study estimated.

That means it takes longer for dust flakes to pick up tracks than astronomers assumed. When Keller and Flynn counted the number of tracks in 14 atmospheric dust grains, the pair found that some of the particles must have spent millions of years out in space — far too long to have come just from between Mars and Jupiter.

Grains specifically from the Kuiper Belt would have wandered 10 million years to reach Earth’s stratosphere, the researchers calculated. That’s “pretty solid evidence that we’re collecting Kuiper Belt dust right here,” Keller says.
Four of the particles contained minerals that had to have formed through interactions with liquid water. That’s surprising; the Kuiper Belt is thought to be too cold for water to be liquid.

“Many of these particles, if they in fact are from the Kuiper Belt, tell you that some of the minerals in Kuiper Belt objects formed in the presence of liquid water,” Keller says. The water probably came from collisions between Kuiper Belt objects that produced enough heat to melt ice, he says.

“I think it’s incredible if Lindsay Keller has shown that he has pieces of Kuiper Belt dust in his lab,” says planetary scientist Carey Lisse of the Johns Hopkins University Applied Physics Laboratory in Laurel, Md. But more work needs to be done to confirm that the dust really came from the Kuiper Belt, he says, and wasn’t just sitting on an asteroid for millions of years. “Lindsay needs to get a lot more samples,” Lisse says. “But I do think he’s on to something.”

Lisse works on NASA’s New Horizons mission, which found plenty of dust in the outer solar system and measured its abundance near Pluto when the spacecraft flew past the dwarf planet in 2015. Based on those results, he finds it unsurprising that some of that dust has made it to Earth. But it is “really cool,” he says. “We can actually try to figure out what the Kuiper Belt is made of.”

Editor’s note: This story was updated April 8, 2019, to correct that the newly calculated flare track rate was about 20 times lower than the rate calculated in 1975, not two orders of a magnitude lower.

A new member of the human genus has been found in a cave in the Philippines, researchers report.

Fossils with distinctive features indicate that the hominid species inhabited the island now known as Luzon at least 50,000 years ago, according to a study in the April 11 Nature. That species, which the scientists have dubbed Homo luzonensis, lived at the same time that controversial half-sized hominids named Homo floresiensis and nicknamed hobbits were roaming an Indonesian island to the south called Flores (SN: 7/9/16, p. 6).
In shape and size, some of the fossils match those of corresponding bones from other Homo species. “But if you take the whole combination of features for H. luzonensis, no other Homo species is similar,” says study coauthor and paleoanthropologist Florent Détroit of the French National Museum of Natural History in Paris.

If the find holds up to further scientific scrutiny, it would add to recent fossil and DNA evidence indicating that several Homo lineages already occupied East Asia and Southeast Asian islands by the time Homo sapiens reached what’s now southern China between 80,000 and 120,000 years ago (SN: 11/14/15, p. 15). The result: an increasingly complicated picture of hominid evolution in Asia.

Excavations in 2007, 2011 and 2015 at Luzon’s Callao Cave yielded a dozen H. luzonensis fossils at first — seven isolated teeth (five from the same individual), two finger bones, two toe bones and an upper leg bone missing its ends, the scientists say. Analysis of the radioactive decay of uranium in one tooth suggested a minimum age of 50,000 years. Based on those fossils, a hominid foot bone found in 2007 in the same cave sediment was also identified as H. luzonensis. It dates to at least 67,000 years ago.
had molars that were especially small, even smaller than those of hobbits, with some features similar to modern humans’ molars. The hominid also had relatively large premolars that, surprisingly, had two or three roots rather than one. Hominids dating to several hundred thousand years ago or more, such as Homo erectus , typically had premolars with multiple roots. H. luzonensis finger and toe bones are curved, suggesting a tree-climbing ability comparable to hominids from 2 million years ago or more.
It’s unclear whether H. luzonensis was as small as hobbits, Détroit says. The best-preserved hobbit skeleton comes from a female who stood about a meter tall. Based on the length of the Callao Cave foot bone, Détroit’s team suspects that H. luzonensis was taller than that, although still smaller than most human adults today.

As with hobbits, H. luzonensis’ evolutionary origins are unknown. Scientists think that hobbits may have descended from seagoing H. erectus groups, and perhaps H. luzonensis did too, writes paleoanthropologist Matthew Tocheri of Lakehead University in Thunder Bay, Canada, in a commentary published with the new report. Evidence suggests that hominids reached Luzon by around 700,000 years ago (SN Online: 5/2/18). So H. erectus may have also crossed the sea from other Indonesian islands or mainland Asia to Luzon and then evolved into H. luzonensis with its smaller body and unusual skeletal traits, Détroit speculates, a process known as island dwarfing.

But some scientists not involved in the research say it’s too soon to declare the Luzon fossils a brand-new Homo species. Détroit’s group, so far, has been unable to extract ancient DNA from the fossils. So “all [evolutionary] possibilities must remain open,” says archaeologist Katerina Douka of the Max Planck Institute for the Science of Human History in Jena, Germany.

The mosaic of fossil features that the team interprets as distinctive, for instance, may have been a product of interbreeding between two or more earlier Homo species, creating hybrids, but not a new species.

Or perhaps a small population of, say, H. erectus that survived on an isolated island like Luzon for possibly hundreds of thousands of years simply acquired some skeletal features that its mainland peers lacked, rather than evolving into an entirely new species, says paleoanthropologist María Martinón-Torres.

Those questions make the new fossils “an exciting and puzzling discovery,” says Martinón-Torres, director of the National Research Centre on Human Evolution in Burgos, Spain.

If the unusual teeth and climbing-ready hand and foot bones found at Callao Cave occurred as a package among Luzon’s ancient Homo crowd, “then that combination is unique and unknown so far” among hominids, Martinón-Torres says. Only a more complete set of fossils, ideally complemented by ancient DNA, she adds, can illuminate whether such traits marked a new Homo member.

Look up at the moon and you’ll see roughly the same patterns of light and shadow that Plato saw about 2,500 years ago. But humankind’s understanding of Earth’s nearest neighbor has changed considerably since then, and so have the ways that scientists and others have visualized the moon.

To celebrate the 50th anniversary of the Apollo 11 moon landing, here are a collection of images that give a sense of how the moon has been depicted over time — from hand-drawn illustrations and maps, to early photographs, to highly detailed satellite images made possible by spacecraft such as NASA’s Lunar Reconnaissance Orbiter.
The images, compiled with help from Marcy Bidney, curator of the American Geographical Society Library at the University of Wisconsin–Milwaukee, show how developments in technology such as the telescope and camera drove ever more detailed views of Earth’s closest celestial companion.

1. Atlas Coelestis, Johann Gabriel Doppelmayr, 1742
   Ancient Greek philosophers like Plato thought the moon and other celestial bodies revolved around a fixed Earth. This 1742 diagram by German scientist Johann Gabriel Doppelmayr depicts that idea. The thinkers saw the moon as perfect and struggled to explain its dark marks. In 1935, one of the moon’s most conspicuous craters was named after Plato.
2. Astronomicum Caesareum, Michael Ostendorfer, 1540
   This hand-colored woodcut by German painter Michael Ostendorfer appears in Astronomicum Caesareum, a vast collection of astronomical knowledge compiled by the German author Petrus Apianus and published in 1540. The image is an example of how astronomers in this early Renaissance period began to stylize the moon by giving it a face, Bidney says.

The book also contains more than 20 exquisitely detailed moving paper instruments, or volvelles, that helped predict lunar eclipses, calculate the position of the stars and more.

3. De Mundo, William Gilbert, ca. 1600
   Created around 1600, this sketch is the oldest known lunar map, and was drawn using the naked eye. William Gilbert, physician to Queen Elizabeth I, imagined that the bright spots were seas and the dark spots land, and gave some features names, such as Regio Magna Orientalis, which translates as “Large Eastern Region” and roughly coincides with the vast lava plain known today as Mare Imbrium.
4. Sidereus Nuncius, Galileo, 1610
   The telescope made it far easier to see the moon’s topography. By Galileo, these 1610 lunar maps are some of the first published to rely on telescope views. His work supported the Copernican idea that the moon, Earth and other planets revolved around the sun.

Although Galileo’s moon drawings were not the first to rely on telescope observations — English astronomer Thomas Harriot created the first sketch in 1609 — Galileo’s were the first published. These images appeared in his astronomical treatise Sidereus Nuncius.

5. Selenographia, Johannes Hevelius, 1647
   In 1647, Polish astronomer Johannes Hevelius, published the first lunar atlas, Selenographia. The book contains more than 40 detailed drawings and engravings, including this one, that show the moon in all its phases. Hevelius also included a glossary of 275 named surface features.

To create his images, Hevelius, a wealthy brewer, constructed a rooftop observatory in Gdańsk and fitted it with a homemade telescope that magnified the moon 40 times. Hevelius is credited with founding the field of selenography, the study of the moon’s surface and physical features.

6. First known lunar photo, John William Draper, 1840
   Photography opened a new way to capture the moon. Taken around 1840 by British-born chemist and physician John William Draper, this daguerreotype is the first known lunar photo. Spots are from mold and water damage.
7. “Moon over Hastings”, Henry Draper, 1863
   Photos of the moon quickly improved. John William Draper’s son Henry, a physician like his father, also developed a passion for photographing the night sky. He shot this detailed image from his Hastings-on-Hudson observatory in New York in 1863, and went on to become a pioneer in astrophotography.
8. Lunar Reconnaissance Orbiter, NASA, 2018
   This 2018 image, from NASA’s Lunar Reconnaissance Orbiter, shows the moon’s familiar face in incredible detail. Now we know its marks are evidence of a violent past and include mountain ranges, deep craters and giant basins filled with hardened lava.
9. Lunar farside, Chang’e-4, 2019
   Countless images now exist of the moon’s illuminated face, but only relatively recently have astronomers managed to capture shots of the moon’s farside, using satellites. Then in February, China’s Chang’e-4 lander and rover became the first spacecraft to land there. This is the first image captured by the probe.