Posts Tagged ‘space’

Returning to Earth from the International Space Station, Canadian astronaut Chris Hadfield remarked how making the right decision is vital in high pressure environments, saying:

Most of the time, you only really get one try to do most of the critical stuff and the consequences are life or death.

Mankind is preparing for a new space age: manned missions to Mars are no longer a distant dream and commercial ventures may open up the prospect for non astronauts to visit other planets. Understanding how gravity impacts the way in which we make decisions has never been more pressing.

All living organisms on Earth have evolved under a constant gravitational field. That’s because gravity is always there and it is part of the background of our perceptual world: we cannot see it, smell it or touch it.

Nevertheless, gravity plays a fundamental role in human behaviour and cognition.

The central nervous system does not have “specialised” sensors for gravity. Rather, gravity is inferred through the integration of several sensory signals in a process termed graviception. This involves vision, our balance system and information from the joints and muscles.

Sophisticated organs inside the inner ear are particularly important in this process. Under terrestrial gravity, when our head is upright, small stones – the vestibular otoliths – are perfectly balanced on a viscous fluid.

When we move the head, for instance looking up, gravity makes the fluid move and this triggers a signal which informs the brain that our head is no longer upright.

Long-duration exposure to zero gravity, such as during space missions, leads to several structural and functional changes in the human body. While the influence of zero gravity on our physical functions has been largely investigated, the effects on decision-making are not yet fully understood.

Given the technical limitations and the expected gap of a few minutes in communication with Earth if we go to Mars, knowing the impact of altered gravity on how people make decisions is essential.

Novelty versus routine

In a nutshell, human behaviour is a constant trade off between the exploitation of familiar but possibly sub-optimal choices and the exploration of new and potentially more profitable alternatives.

For example, in a restaurant you can exploit by choosing your usual chocolate cake, or you can explore by trying that tiramisu that you’ve not had before. Thus, exploitation involves routine behaviour, while exploration involves varying choices.

We investigated whether alterations in gravity impact the choice between routine and novel behaviour. We asked participants to come to the lab and produce sequences of numbers as randomly as possible.

Every time they heard a beep sound, they needed to name a number between one and nine. Importantly, there was no time to think or to count, just name a number.

Critically, this task requires our brain to suppress routine responses and generate novel responses, and it can be considered a proxy for successful adaptive behaviour.

But how does this change under the influence of gravity? We manipulated how the otoliths sense gravity by changing the orientation of participants’ bodies with respect to the direction of terrestrial gravity by asking them to lie down.

When we are upright, our body and otoliths are congruent with the direction of gravity, while when we are lying down they are orthogonal (at right angles).

This is a very efficient laboratory manipulation, which allows us to mimic alterations of gravitational signals reaching the brain. It is actually a better way to study the effects of gravity than sending someone to space.

That’s because when we are in space we are also affected by weightlessness, radiation and isolation – and it can be hard to separate what effect the lack of gravity alone has.

Our results indicate that lying down does seem to influence how people make decisions, with participants struggling with random number generation. This indicates that people are therefore less prone to generating novel behaviours in the absence of gravity.

This may be of importance to the planning of actual space missions. Astronauts are in an extremely challenging environment in which decisions must be made quickly and efficiently. An automatic preference for routine or stereotyped options might not help with complex problem solving, and could even place life at risk.

The results add to research suggesting that people also suffer changes in perception and cognition when under conditions mimicking zero-gravity. The absence of gravity can be profoundly unsettling, and can potentially compromise performance levels in many ways.

This suggests that astronauts may benefit from some sort of cognitive enhancement training to help them overcome the effects of altered gravity on the brain, and to assure successful and safe manned space missions.The Conversation


sounds like a science fiction plotline—a space elevator. Now, it may be a possibility.

Scientists at Japan’s Shizuoka University are testing the space elevator, a potential solution to getting materials or satellites off of Earth. On September 11, the team will launch a scale model of the motorized box into Earth’s orbit.

The elevator consists of two cubic satellites that are only 4 inches on each side. The satellites will be connected by a 33-foot steel cable. The parts of the machine will launch on H-IIB rocket from the Japan Aerospace Exploration Agency’s Tanegashima Space Center to the International Space Station (ISS).

“It’s going to be the world’s first experiment to test elevator movement in space,” a university spokesman told AFP. From the ISS, the two satellites will be released into space. On the cable that attaches the satellites, a container will move using a motor. There will be a camera attached to the satellites that will record the container in action.

In the past, astronauts have extended a cable in space, but this is the first time that a container will move along a cable. Scientists have struggled with creating a space elevator in the past, so if this experiment is successful it will be a welcome step forward in the process. A space elevator could provide a low-cost solution to send materials—or people—to the station. One difficult part of creating a space elevator is finding the right material for a cable.

“No current material exists with sufficiently high tensile strength and sufficiently low density out of which we could construct the cable,” Keith Henson, a technologist and engineer, told Gizmodo. “There’s nothing in sight that’s strong enough to do it — not even carbon nanotubes.” And if to much pressure is applied, there’s the worry of the cable unzipping. The elevator would also have to avoid space junk and satellites, withstand winds, and be able to fight the gravity from the Sun, Moon, and Earth.

However, the Japanese team thinks the elevator could work. Obayashi Corp., which is serving as the technical advisor to the Shizuoka University researchers, is working on their own elevator experiment where six oval shaped cars that can hold 30 people each would ascend around 22,370 miles into space. The test next week could provide valuable data in making those plans.

“In theory, a space elevator is highly plausible.” Yoji Ishikawa, who leads the Obayashi research team, told the Japanese paper The Mainichi. “Space travel may become something popular in the future.”

The detailed, all-sky picture of the infant universe created from nine years of WMAP data. The image reveals 13.77 billion year old temperature fluctuations (shown as color differences) that correspond to the seeds that grew to become the galaxies. The signal from our galaxy was subtracted using the multi-frequency data. This image shows a temperature range of ± 200 microKelvin.CREDIT: NASA/WMAP SCIENCE TEAM

by Jesse Shanahan

In a study published earlier this month, a team of theoretical physicists is claiming to have discovered the remnants of previous universes hidden within the leftover radiation from the Big Bang. Our universe is a vast collection of observable matter, like gas, dust, stars, etc., in addition to the ever-elusive dark matter and dark energy. In some sense, this universe is all we know, and even then, we can only directly study about 5% of it, leaving 95% a mystery that scientists are actively working to solve. However, this group of physicists is arguing that our universe isn’t alone; it’s just one in a long line of universes that are born, grow, and die. Among these scientists is mathematical physicist Roger Penrose, who worked closely with Stephen Hawking and currently is the Emeritus Rouse Ball Professor of Mathematics at Oxford University. Penrose and his collaborators follow a cosmological theory called conformal cyclic cosmology (CCC) in which universes, much like human beings, come into existence, expand, and then perish.

As a universe ages, it expands, and the constituent parts grow farther and farther apart from each other. Consequently, the interactions between galaxies that drive star formation and evolution become rarer. Eventually, the stars die out, and the remaining gas and dust is captured by black holes. In one of his most famous theories, Stephen Hawking proposed that this isn’t the end; black holes might have a way to slowly lose mass and energy by radiating certain particles. So, after many eons, the remaining black holes in the universe would disappear, leaving only disparate particles. Seemingly a wasteland, this end-state eventually mirrors the environment of our universe’s birth, and so, the cycle starts anew.

universe 2
Artist’s logarithmic scale conception of the observable universe with the Solar System at the center, inner and outer planets, Kuiper belt, Oort cloud, Alpha Centauri, Perseus Arm, Milky Way galaxy, Andromeda galaxy, nearby galaxies, Cosmic Web, Cosmic microwave radiation and Big Bang’s invisible plasma on the edge.CREDIT: WIKIPEDIA/PABLO CARLOS BUDASSI

When our universe was very young, before any recognizable components like stars, planets, or galaxies formed, it was filled with a dense, hot soup of plasma. As the universe expanded, it cooled, and eventually, particles could combine to form atoms. Eventually, the interaction and fusion of these atoms resulted in all of the matter that we observe today. However, we can still observe the leftover radiation from that initial, dense period in our universe’s history. This leftover glow, called the Cosmic Microwave Background (CMB), is the oldest electromagnetic radiation, and it fills the entirety of our universe. If the CCC theory were true, then there would be hints of previous universes in our universe’s CMB.

At the end of a universe, when those final black holes dissolve, CCC theory states they should leave behind a signature that would survive the death of that universe and persist into the next. Although not definitive proof of previous universes, detecting that signature would be strong evidence in support of CCC theory. In searching for these “Hawking points”, cosmologists face a difficult obstacle as the CMB is faint and varies randomly. However, Penrose is claiming that a comparison between a model CMB with Hawking points and actual data from our CMB has proven that Hawking points actually exist. If true, this would be the first-ever detection of evidence from another universe.

Unfortunately, as groundbreaking as this discovery seems, the scientific community has largely dismissed it. One of the fundamental characteristics of the CMB is that, although it has patterns, the variations are entirely statistically random. In fact, Penrose’s former collaborator, Stephen Hawking, spotted his own initials in the CMB while others have found a deer, a parrot, and numerous other recognizable shapes in the noise. Similarly, the Wilkinson Anisotropy Microscope Probe that mapped the CMB released an interactive image where you can search for familiar shapes and patterns. An avoidable result of both these random fluctuations and the sheer size of the CMB is that if scientists look hard enough, they can find whatever pattern they need, like the existence of Hawking points, perhaps. Another criticism of Penrose’s claim is that if CCC theory holds true, our universe should have tens of thousands of Hawking points in the CMB. Regrettably, Penrose could find only about 20.

Still, the possibility of alternate universes, whether long-dead or existing in parallel to our own, is tantalizing. Many other theories also claim to find traces of other universes hiding in the patterns of the CMB as well. Although it sounds like science fiction, we are left to wonder: is this just the cosmological equivalent of seeing shapes in random clouds or will scientists one day discover that we are one among many infinite universes?

Jesse Shanahan is an astrophysicist, EMT, and science communicator. For more space and language news, follow her on Twitter here.


The Milky Way is a zombie. No, not really, it doesn’t go around eating other galaxies’ brains. But it did “die” once, before flaring back to life. That’s what a Japanese scientist has ascertained after peering into the chemical compositions of our galaxy’s stars.

In a large section of the Milky Way, the stars can be divided into two distinct populations based on their chemical compositions. The first group is more abundant in what is known as α elements – oxygen, magnesium, silicon, sulphur, calcium and titanium. The second is less abundant in α elements, and markedly more abundant in iron.

The existence of these two distinct populations implies that something different is happening during the formation stages. But the precise mechanism behind it was unclear.

Astronomer Masafumi Noguchi of Tohoku University believes his modelling shows the answer. The two different populations represent two different periods of star formation, with a quiescent, or “dormant” period in between, with no star formation.

Based on the theory of cold flow galactic accretion proposed back in 2006, Noguchi has modelled the evolution of the Milky Way over a 10 billion-year period.

Originally, the cold flow model was suggested for much larger galaxies, proposing that massive galaxies form stars in two stages. Because of the chemical composition dichotomy of its stars, Noguchi believes this also applies to the Milky Way.

That’s because the chemical composition of stars is dependent on the gases from which they are formed. And, in the early Universe, certain elements – such as the heavier metals – hadn’t yet arrived on the scene, since they were created in stars, and only propagated once those stars had gone supernova.

In the first stage, according to Noguchi’s model, the galaxy is accreting cold gas from outside. This gas coalesces to form the first generation of stars.

After about 10 million years, which is a relatively short timescale in cosmic terms, some of these stars died in Type II supernovae. This propagated the α elements throughout the galaxy, which were incorporated into new stars.

But, according to the model, it all went a bit belly-up after about 3 billion years.

“When shock waves appeared and heated the gas to high temperatures 7 billion years ago, the gas stopped flowing into the galaxy and stars ceased to form,” a release from Tohoku University says.

During a hiatus of about 2 billion years, a second round of supernovae took place – the much longer scale Type Ia supernova, which typically occur after a stellar lifespan of about 1 billion years.

It’s in these supernovae that iron is forged, and spewed out into the interstellar medium. When the gas cooled enough to start forming stars again – about 5 billion years ago – those stars had a much higher percentage of iron than the earlier generation. That second generation includes our Sun, which is about 4.6 billion years old.

Noguchi’s model is consistent with recent research on our closest galactic neighbour, Andromeda, which is thought to be in the same size class as the Milky Way. In 2017, a team of researchers published a paper that found Andromeda’s star formation also occurred in two stages, with a relatively quiescent period in between.

If the model holds up, it may mean that the evolution models of galaxies need to be revised – that, while smaller dwarf galaxies experience continuous star formation, perhaps a “dead” period is the norm for massive ones.

If future observations confirm, who’s up for renaming our galaxy Frankenstein?

Noguchi’s paper has been published in the journal Nature.

FOR DECADES MARS has teased scientists with whispers of water’s presence. Valleys and basins and rivers long dry point to the planet’s hydrous past. The accumulation of condensation on surface landers and the detection of vast subterranean ice deposits suggest the stuff still lingers in gaseous and solid states. But liquid water has proved more elusive. Evidence to date suggests it flows seasonally, descending steep slopes in transient trickles every Martian summer. The search for a big, enduring reservoir of wet, potentially life-giving water has turned up nothing. Until now.

The Italian Space Agency announced Wednesday that researchers have detected signs of a large, stable body of liquid water locked away beneath a mile of ice near Mars’ south pole. The observations were recorded by the Mars Advanced Radar for Subsurface and Ionosphere Sounding instrument—Marsis for short. “Marsis was born to make this kind of discovery, and now it has,” says Roberto Orosei, a radioastronomer at the National Institute for Astrophysics, who led the investigation. His team’s findings, which appear in this week’s issue of Science, raise tantalizing questions about the planet’s geology—and its potential for harboring life.

Marsis collected its evidence from orbit, flying aboard the European Space Agency’s Mars Express spacecraft. It works by transmitting pulses of low-frequency electromagnetic waves toward the red planet. Some of those waves interact with features at and below the Martian surface and reflect back toward the instrument, carrying clues about the planet’s geological composition. Conceptually, using the instrument to study Mars’ polar regions couldn’t be more straightforward: Just point it toward the ice and see what bounces back.

In practice, though, it’s a lot more complicated. Marsis spends relatively little time above Planum Australe, the southern polar plane of Mars and the focus of Orosei’s team’s investigation. That meant the researchers could only listen for echoes periodically. It would take many readings—and many years—to get a clear picture of what lies hidden beneath the planet’s southern ice cap. So in May of 2012, on the heels of a software upgrade that enabled Marsis to acquire more detailed data, the researchers began their survey.

Three and a half years and 29 observations later, they had a radiogrammatic map of Mars’ southern polar plane. When they cross-referenced all their measurements, something immediately seized their attention: Bright reflections in the radar signals, corresponding to what Orosei now calls “a well-defined anomaly” some 12 miles across and several feet deep, roughly one mile beneath the surface of the polar ice cap. The surface of an ice cap tends to reflect radar waves more strongly than the regions below it. But on multiple passes, Marsis had detected uncommonly strong echoes originating from beneath the southern pole.

Or rather: Uncommonly strong for a solid material.

Analyses of subglacial lakes on our own planet—like the ones beneath the Antarctic and Greenland ice sheets—have shown that water reflects radar more strongly than rock and sediment. And in fact, the radar profile of this region of Mars’ southern pole resembles those of subglacial lakes here on Earth.

The researchers looked for other explanations for the bright signals. A layer of frozen carbon dioxide above or below the polar cap, for example, could conceivably produce readings like the ones they observed—though the researchers deemed this, and all other explanations that they considered, less likely than the presence of liquid water.

“I can’t absolutely prove it’s water, but I sure can’t think of anything else that looks like this thing does other than liquid water,” says Richard Zurek, chief scientist for the Mars Program Office at NASA’s Jet Propulsion Laboratory, who was unaffiliated with the study. “Maybe that has to do with a shortage of imagination on my part,” he adds, “but it probably has to do with a shortage of data, too.” More radar observations, he says, could give rise to explanations scientists haven’t even thought of yet—and more questions, too.

Not that there’s a shortage of unanswered questions. Still unclear is how the water remains liquid at temperatures tens of degrees below 0° Celsius. Orosei and his team think the answer could be magnesium, calcium, and sodium salts, all of which are present in Martian rock, that have dissolved in the water, lowering its freezing point.

Another question is whether future observations by Marsis and other spacecraft will detect more reservoirs beneath Mars’ southern ice cap. “If this lake is a single occurrence, if there is no other liquid water anywhere else, then the implication would be that we are seeing a quirk of nature—an effect of residual decay, a hydrothermal vent, some thermal irregularity in the crust,” Orosei says. “But, if we were to find that Mars possesses not one subglacial lake, but several, that would change the game.”

More lakes would suggest that the conditions necessary for their existence aren’t so rare. And if those conditions have persisted throughout the planet’s history, then subsurface reservoirs of liquid water could serve as a bridge to the early environment of Mars—a time capsule of sorts from a period billions of years ago, when Mars was a warm, wet planet.

Which, of course, raises the biggest question of all: Could there be life in the waters beneath Mars’ southern ice caps?

It’s certainly possible, says Montana State University glaciologist John Priscu. An expert in the biogeochemistry and microbiology of subglacial environments here on Earth, Priscu led the first team to discover microbial life in a lake beneath the West Antarctic ice sheet. “You need three things for life: liquid water; an energy source, like leaching minerals, which we know Mars has; and a biological seed,” he says. It’s plausible that the lake beneath Mars’ southern pole possesses the first two. As for the whole spark-of-life thing, “I’m not sure we’ll ever know where the seed comes from,” he says. But if Earth got a seed, maybe Mars did, too.

But we’re getting ahead of ourselves. “It’s tempting to think that if life ever evolved on Mars, it would have to be present today,” Orosei says, a subglacial lake like the one his team discovered would be an excellent place to look. But first comes the search for more lakes. And after that, perhaps landers equipped with drills. “Going from zero bodies of water to one is a big change, for sure,” Orosei says, “but the full extent of this discovery depends on what we find next.”

Zinnias such as this one were among the first flowers to be grown on the International Space Station.

Researchers on the International Space Station are growing plants in systems that may one day sustain astronauts traveling far across the solar system and beyond.

Vibrant orange flowers crown a leafy green stem. The plant is surrounded by many just like it, growing in an artificially lit greenhouse about the size of a laboratory vent hood. On Earth, these zinnias, colorful members of the daisy family, probably wouldn’t seem so extraordinary. But these blooms are literally out of this world. Housed on the International Space Station (ISS), orbiting 381 kilometers above Earth, they are among the first flowers grown in space and set the stage for the cultivation of all sorts of plants even farther from humanity’s home planet.

Coaxing this little flower to bloom wasn’t easy, Gioia Massa, a plant biologist at NASA’s Kennedy Space Center in Florida, tells The Scientist. “Microgravity changes the way we grow plants.” With limited gravitational tug on them, plants aren’t sure which way to send their roots or shoots. They can easily dry out, too. In space, air and water don’t mix the way they do on Earth—liquid droplets glom together into large blobs that float about, instead of staying at the roots.

Massa is part of a group of scientists trying to overcome those challenges with a benchtop greenhouse called the Vegetable Production System, or Veggie. The system is a prototype for much larger greenhouses that could one day sustain astronauts on journeys to explore Mars. “As we’re looking to go deeper into space, we’re going to need ways to support astronaut crews nutritionally and cut costs financially,” says Matthew Romeyn, a long-duration food production scientist at Kennedy Space Center. “It’s a lot cheaper to send seeds than prepackaged food.”

In March 2014, Massa and colleagues developed “plant pillows”—small bags with fabric surfaces that contained a bit of soil and fertilizer in which to plant seeds. The bags sat atop a reservoir designed to wick water to the plants’ roots when needed (Open Agriculture, 2:33-41, 2017). At first, the ISS’s pillow-grown zinnias were getting too much water and turning moldy. After the crew ramped up the speed of Veggie’s fans, the flowers started drying out—an issue relayed to the scientists on the ground in 2015 by astronaut Scott Kelly, who took a special interest in the zinnias. Kelly suggested the astronauts water the plants by hand, just like a gardener would on Earth. A little injection of water into the pillows here and there, and the plants perked right up, Massa says.

With the zinnias growing happily, the astronauts began cultivating other flora, including cabbage, lettuce, and microgreens—shoots of salad vegetables—that they used to wrap their burgers and even to make imitation lobster rolls. The gardening helped to boost the astronauts’ diets, and also, anecdotally, brought them joy. “We’re just starting to study the psychological benefits of plants in space,” Massa says, noting that gardening has been shown to relieve stress. “If we’re going to have this opportunity available for longer-term missions, we have to start now.”

The team is currently working to make the greenhouses less dependent on people, as tending to plants during space missions might take astronauts away from more-critical tasks, Massa says. The researchers recently developed Veggie PONDS (Passive Orbital Nutrient Delivery System) with help from Techshot and Tupperware Brands Corporation. This system still uses absorbent mats to wick water to plants’ seeds and roots, but does so more consistently by evenly distributing the moisture. As a result, the crew shouldn’t have to keep such a close eye on the vegetation, and should be able to grow hard-to-cultivate garden plants, such as tomatoes and peppers. Time will tell. NASA sent Veggie PONDS to the ISS this past March, and astronauts are just now starting to compare the new system’s capabilities to those of Veggie.

“What they are doing on the ISS is really neat,” says astronomer Ed Guinan of the University of Pennsylvania. If astronauts are going to venture into deep space and be able to feed themselves, then they need to know how plants grow in environments other than Earth, and which grow best. The projects on the ISS will help answer those questions, he says. Guinan was so inspired by the ISS greenhouses he started his own project in 2017 studying how plants would grow in the soil of Mars—a likely future destination for manned space exploration. He ordered soil with characteristics of Martian dirt and told students in his astrobiology course, “You’re on Mars, there’s a colony there, and it’s your job to feed them.” Most of the students worked to grow nutritious plants, such as kale and other leafy greens, though one tried hops, a key ingredient in beer making. The hops, along with some of the other greens, grew well, Guinan reported at the American Astronomical Society meeting in January.

Yet, if and when astronauts go to Mars, they probably won’t be using the Red Planet’s dirt to grow food, notes Gene Giacomelli, a horticultural engineer at the University of Arizona. There are toxic chemicals called perchlorates to contend with, among other challenges, making it more probable that a Martian greenhouse will operate on hydroponics, similar to the systems being tested on the ISS. “The idea is to simplify things,” says Giacomelli, who has sought to design just such a greenhouse. “If you think about Martian dirt, we know very little about it—so do I trust it is going to be able to feed me, or do I take a system I know will feed me?”

For the past 10 years, Giacomelli has been working with others on a project, conceived by now-deceased business owner Phil Sadler, to build a self-regulating greenhouse that could support a crew of astronauts. This is not a benchtop system like you find on the space station, but a 5.5-meter-long, 2-meter-diameter cylinder that unfurls into an expansive greenhouse with tightly controlled circulation of air and water. The goal of the project, which was suspended in December due to lack of funding, was to show that the lab-size greenhouse could truly sustain astronauts. The greenhouse was only partially successful; the team calculated that a single cylinder would provide plenty of fresh drinking water, but would produce less than half the daily oxygen and calories an astronaut would need to survive a space mission. Though the project is on hold, Giacomelli says he hopes it will one day continue.

This kind of work, both here and on the ISS, is essential to someday sustaining astronauts in deep space, Giacomelli says. And, if researchers can figure out how to make such hydroponic systems efficient and waste-free, he notes, “the heck with Mars and the moon, we could bring that technology back to Earth.”

This view of Pluto’s Sputnik Planitia nitrogen-ice plain was captured by NASA’s New Horizons spacecraft during its flyby of the dwarf planet in July 2015.

At its heart, Pluto may be a gigantic comet.

Researchers have come up with a new theory about the dwarf planet’s origins after taking a close look at Sputnik Planitia, the vast nitrogen-ice glacier that constitutes the left lobe of Pluto’s famous “heart” feature.

“We found an intriguing consistency between the estimated amount of nitrogen inside the glacier and the amount that would be expected if Pluto was formed by the agglomeration of roughly a billion comets or other Kuiper Belt objects similar in chemical composition to 67P, the comet explored by Rosetta,” Chris Glein, a scientist at the Southwest Research Institute (SwRI) in San Antonio, said in a statement.

The European Space Agency’s Rosetta mission orbited Comet 67P/Churyumov-Gerasimenko from 2014 through 2016. The orbiting mothership also dropped a lander named Philae onto the icy body, pulling off the first-ever soft touchdown on a comet’s surface. (The Kuiper Belt is the ring of frigid objects beyond Neptune’s orbit; Pluto is the belt’s largest resident.)

Glein and his SwRI colleague Hunter Waite devised the new Pluto-formation scenario after analyzing data from Rosetta and NASA’s New Horizons mission, which flew by Pluto in July 2015.

The scientists also made some inferences about the dwarf planet’s evolution in their new study, which was published online Wednesday (May 23) in the journal Icarus.

“Our research suggests that Pluto’s initial chemical makeup, inherited from cometary building blocks, was chemically modified by liquid water, perhaps even in a subsurface ocean,” Glein said.

Glein and Waite aren’t claiming to have nailed down Pluto’s origin definitively; a “solar model,” in which the dwarf planet coalesced from cold ices with a chemical composition closer to that of the sun, also remains in play, the duo said.

“This research builds upon the fantastic successes of the New Horizons and Rosetta missions to expand our understanding of the origin and evolution of Pluto,” Glein said.

“Using chemistry as a detective’s tool, we are able to trace certain features we see on Pluto today to formation processes from long ago,” he added. “This leads to a new appreciation of the richness of Pluto’s ‘life story,’ which we are only starting to grasp.”

Rosetta’s mission ended in September 2016, when the probe’s handlers steered it to an intentional crash-landing on 67P’s surface. New Horizons’ work, however, is far from done. The NASA spacecraft is speeding toward a flyby of a small Kuiper Belt object known officially as 2014 MU69 (and unofficially as Ultima Thule). This close encounter, which will occur on Jan. 1, 2019, about 1 billion miles (1.6 billion kilometers) beyond Pluto’s orbit, is the centerpiece of New Horizons’ extended mission.