Chandrayaan-1 Orbiter Spots Water-Rich Volcanic Deposits on Lunar Surface

Chandrayaan-1 Orbiter Spots Water-Rich Volcanic Deposits on Lunar Surface

The volcanic beads don’t contain a lot of water — about 0.05% by weight — but the deposits are large, and the water could potentially be extracted.

The research, published in the journal Nature Geoscience, was led by Brown University associate professor Ralph Milliken.

“Detecting the water content of lunar volcanic deposits using orbital instruments is no easy task,” said Dr. Milliken and his co-author, Dr. Shuai Lifrom the University of Hawaii.

“Researchers use orbital spectrometers to measure the light that bounces off a planetary surface.”

“By looking at which wavelengths of light are absorbed or reflected by the surface, they can get an idea of which minerals and other compounds are present.”

“The problem is that the lunar surface heats up over the course of a day, especially at the latitudes where these pyroclastic deposits are located. That means that in addition to the light reflected from the surface, the spectrometer also ends up measuring heat.”

“That thermally emitted radiation happens at the same wavelengths that we need to use to look for water. So in order to say with any confidence that water is present, we first need to account for and remove the thermally emitted component,” Dr. Milliken explained.

To do that, he and Dr. Li used laboratory-based measurements of samples returned from the Apollo missions, combined with a detailed temperature profile of the areas of interest on the Moon’s surface.

Using the new thermal correction, they looked at data from Chandrayaan-1’s Moon Mineralogy Mapper.

They found evidence of water in nearly all of the large pyroclastic deposits that had been previously mapped across the Moon’s surface, including deposits near the Apollo 15 and 17 landing sites where the water-bearing glass bead samples were collected.

“The distribution of these water-rich deposits is the key thing,” Dr. Milliken said. “They’re spread across the surface, which tells us that the water found in the Apollo samples isn’t a one-off.”

“Lunar pyroclastics seem to be universally water-rich, which suggests the same may be true of the mantle.”

The idea that the interior of the Moon is water-rich raises interesting questions about the Moon’s formation.

Planetary researchers think the Moon formed from debris left behind after an object about the size of Mars slammed into the Earth very early in the history of Solar System.

One of the reasons they had assumed the Moon’s interior should be dry is that it seems unlikely that any of the hydrogen needed to form water could have survived the heat of that impact.

“The growing evidence for water inside the Moon suggests that water did somehow survive, or that it was brought in shortly after the impact by asteroids or comets before the Moon had completely solidified,” Dr. Li said.

“The exact origin of water in the lunar interior is still a big question.”

Astronomers discover rare fossil relic of early Milky Way

Astronomers discover rare fossil relic of early Milky Way

Terzan 5, 19 000 light-years from Earth in the constellation of Sagittarius (the Archer) and in the direction of the galactic centre, has been classified as a globular cluster for the forty-odd years since its detection. Now, an Italian-led team of astronomers have discovered that Terzan 5 is like no other globular cluster known. The team scoured data from the Multi-conjugate Adaptive Optics Demonstrator [1], installed at the Very Large Telescope, as well as from a suite of other ground-based and space telescopes [2]. They found compelling evidence that there are two distinct kinds of stars in Terzan 5 which not only differ in the elements they contain, but have an age-gap of roughly 7 billion years [3].

The ages of the two populations indicate that the star formation process in Terzan 5 was not continuous, but was dominated by two distinct bursts of star formation. “This requires the Terzan 5 ancestor to have large amounts of gas for a second generation of stars and to be quite massive. At least 100 million times the mass of the Sun,” explains Davide Massari, co-author of the study, from INAF, Italy, and the University of Groningen, Netherlands.

Its unusual properties make Terzan 5 the ideal candidate for a living fossil from the early days of the Milky Way. Current theories on galaxy formation assume that vast clumps of gas and stars interacted to form the primordial bulge of the Milky Way, merging and dissolving in the process.

“We think that some remnants of these gaseous clumps could remain relatively undisrupted and keep existing embedded within the galaxy,” explains Francesco Ferraro from the University of Bologna, Italy, and lead author of the study. “Such galactic fossils allow astronomers to reconstruct an important piece of the history of our Milky Way.”

While the properties of Terzan 5 are uncommon for a globular cluster, they are very similar to the stellar population which can be found in the galactic bulge, the tightly packed central region of the Milky Way. These similarities could make Terzan 5 a fossilised relic of galaxy formation, representing one of the earliest building blocks of the Milky Way.

This assumption is strengthened by the original mass of Terzan 5 necessary to create two stellar populations: a mass similar to the huge clumps which are assumed to have formed the bulge during galaxy assembly around 12 billion years ago. Somehow Terzan 5 has managed to survive being disrupted for billions of years, and has been preserved as a remnant of the distant past of the Milky Way.

“Some characteristics of Terzan 5 resemble those detected in the giant clumps we see in star-forming galaxies at high-redshift, suggesting that similar assembling processes occurred in the local and in the distant Universe at the epoch of galaxy formation,” continues Ferraro.

Hence, this discovery paves the way for a better and more complete understanding of galaxy assembly. “Terzan 5 could represent an intriguing link between the local and the distant Universe, a surviving witness of the Galactic bulge assembly process,” explains Ferraro while commenting on the importance of the discovery. The research presents a possible route for astronomers to unravel the mysteries of galaxy formation, and offers an unrivaled view into the complicated history of the Milky Way.

Small, distant worlds are either big Earths or little Neptunes

Small, distant worlds are either big Earths or little Neptunes

This conclusion emerges from data collected by the Kepler space telescope. It was charged with hunting for alien planets, meaning those outside our solar system. Now Kepler’s initial mission is over and its data in-hand.

Scientists released Kepler’s final tally of so-called exoplanets June 19 at a news conference. The spacecraft has turned up 4,034 of these candidate planets. Among them are 49 rocky worlds, including 10 newly discovered ones. These sit in their stars’ Goldilocks zones. That means they fall within a region that’s not too hot and not too cold to support life as we know it. To date, 2,335 of the candidates have been confirmed as planets. That includes about 30 rocky worlds that are in potentially habitable zones.

Benjamin Fulton studies these alien worlds. He works at the University of Hawaii at Manoa and at the California Institute of Technology (Caltech) in Pasadena. He and his colleagues made careful measurements of the candidate planets’ stars. This turned up something unexpected. Few planets had a radius more than 1.5 times that of Earth but less than twice as big as Earth’s.

This split the planet into two types, based on size. Rocky ones, like Earth, had the smaller radii (under 1.5 times the size of Earth’s). Gassy planets (the Neptune-like ones) tended to have a radius that was from 2 to 3.5 times the size of Earth’s.

“This is a major new division in the family tree of exoplanets,” Fulton reports. It is “somewhat analogous to the discovery that mammals and lizards are separate branches on the tree of life,” he says.

The Kepler space telescope launched in 2009. It had one ultimate goal: to identify the fraction of stars like the sun that host planets like Earth. To do this, it stared at a single patch of sky in the constellation Cygnus for four years. Kepler watched sunlike stars for telltale dips in brightness. Such dips point to when a planet passes in front of its star. Known as a transit, one might think of it as a mini or partial-eclipse.

The Kepler team has still not yet calculated what share of the sun-like stars in Kepler’s eye host planets in  the Goldilocks zone. But astronomers are confident that they finally have enough data to do so, said Susan Thompson. She is an astronomer at the SETI Institute in Mountain View, Calif. She presented the new data during the Kepler/K2 Science Conference IV being held at NASA’s Ames Research Center in Moffett Field, Calif. (K2 refers to Kepler’s second mission. It began when the telescope’s stabilizing reaction wheels broke.)

Thompson and her colleagues ran the Kepler dataset through “Robovetter” software. It acted like a sieve to catch all of the potential planets that the dataset contained. Running fake planet data through the software pinpointed how likely it was to confuse other signals for a planet or to miss true planets.

“This is the first time we have a population [of exoplanets] that’s really well-characterized,” Thompson says.

Astronomers’ knowledge of exoplanets is only as good as their knowledge of the planets’ host stars. So, in a separate study, Fulton and his colleagues turned to the Keck telescope in Hawaii. They used it to precisely measure the sizes of 1,300 planet-hosting stars that were in the Kepler telescope’s field of view. That let them compare the dips in light due to a planet crossing in front of its star to that star’s real size. Those star sizes helped pin down the sizes of the planets with four times more precision than ever before.

The split in planet types the team found could come from small differences in the planets’ sizes, compositions and distances from their stars. Young stars emit powerful winds of charged particles. These winds can blow a growing planet’s atmosphere away.

Bigger planets have more gravity, which helps them hold on to a thicker atmosphere. If a planet was too close to its star or too small to hold its atmosphere tightly — less than 75 percent larger than Earth — it would lose its atmosphere and end up in the smaller group. The planets that look more like Neptune today either had more gas to begin with. Or, they grew up in a gentler environment, Fulton  now concludes.

That split could have implications for the abundance of life in the Milky Way. That’s our galaxy. Consider the surfaces of mini-Neptunes, if they exist. They would suffer under the crushing pressure of a thick atmosphere.

“These would not be nice places to live,” Fulton said. “Our result sharpens up the dividing line between potentially habitable planets and those that are inhospitable.”

Better telescopes will sharpen the dividing line even further. Two such telescopes are slated to launch in 2018. The Transiting Exoplanet Survey Satellite will fill in the details of the exoplanet landscape with more observations of planets around bright stars. The James Webb Space Telescope will be able to check the atmospheres of those planets for signs of life.

“We can now really ask the question, ‘Is our planetary system unique in the galaxy?’” says Courtney Dressing. She is an exoplanet astronomer at Caltech. “My guess is the answer’s no. We’re not that special.”

How Earth got its moon

How Earth got its moon

The story of our moon’s origin does not add up. Most scientists think that that the moon formed in the earliest days of our solar system. That would have been back around 4.5 billion years ago. At that time, some scientists suspect, a Mars-sized rocky object — what they call a protoplanet — smacked into the young Earth. This collision would have sent debris from both worlds hurling into orbit. Some of the rubble eventually would have stuck together, creating our moon.

Or maybe not.

Astronomers refer to that protoplanet as Theia (THAY-ah). Named for the Greek goddess of sight, no one knows if this big rock ever existed — because if it did, it would have died in that violent collision with Earth.

And here’s why some astronomers have come to doubt Theia was real: If it smashed into Earth and helped form the moon, then the moon should look like a hybrid of Earth and Theia. Yet studies of lunar rocks show that the chemical composition of Earth and its moon are exactly the same. So that planet-on-planet impact story appears to have some holes in it.

That has prompted some researchers to look for other moon-forming scenarios. One proposal: A string of impacts created mini moons largely from Earth material. Over time, they might have merged to form one big moon.

“Multiple impacts just make more sense,” says Raluca Rufu. She’s a planetary scientist at the Weizmann Institute of Science in Rehovot, Israel. “You don’t need this one special impactor to form the moon.”

But Theia shouldn’t be left on the cutting room floor — at least not yet. Earth and Theia could have been built largely from the same type of material, new research suggests. Then they would have had a similar chemical recipe. There is no sign of “other” material on the moon, this explanation argues, because nothing about Theia was different.

“I’m absolutely on the fence between these two opposing ideas,” says Edward Young. He studies cosmochemistry — the chemistry of the universe — at the University of California, Los Angeles. Determining which story is correct is going to take more research. But the answer could offer profound insights into the evolution of the early solar system, Young says.

Mother of the moon

Earth’s moon is an oddball. Most other moons in our solar system live way out among the gas giants, such as Saturn and Jupiter. The only other terrestrial planet with orbiting moons is Mars. Its moons, Phobos and Deimos, are small. The leading explanation for them is that likely were once asteroids. At some point, they were captured by the Red Planet’s gravity. Earth’s moon is too big for that scenario. If the moon had come in from elsewhere, it probably would have crashed into Earth or escaped and fled into space.

An alternate explanation dates from the 1800s. It suggests that moon-forming material flew off of a fast-spinning young Earth. (Imagine children tossed from an out-of-control merry-go-round.) That idea fell out of favor, though, when scientists calculated the spin speeds required. They were impossibly fast.

In the mid-1970s, planetary scientists proposed the giant-impact hypothesis. (Later, in 2000, they named that mysterious planet-sized body as Theia.) The notion of a big rocky collision made sense. After all, the early solar system was like a game of cosmic billiards. Giant space-rock smash-ups were common.

But a 2001 study of rocks collected during NASA’s Apollo missions to the moon cast doubt on the giant-impact hypothesis. Research showed that Earth and its moon were surprisingly alike. To figure out a rock’s origin, scientists measure the relative abundance of different forms of oxygen. Called isotopes (EYE-so-toaps), they are forms of an element with different masses. (The reason they differ: Although each has the same number of protons in its nuclei, they have different numbers of neutrons.)

Cassini Sees Methane Clouds in Titan’s Summer Skies

Cassini Sees Methane Clouds in Titan’s Summer Skies

Compared to earlier in Cassini’s mission, most of the surface in Titan’s northern high latitudes is now illuminated by the Sun.

Summer solstice in the Saturn system (the longest day of summer in the northern hemisphere and the shortest day of winter in the southern hemisphere) occurred on May 24, 2017.

This image was taken with Cassini’s narrow-angle camera on June 9, 2017, using a spectral filter that preferentially admits wavelengths of near-IR light centered at 938 nm.

Cassini obtained the view at a distance of about 315,000 miles (507,000 km) from Titan.

The spacecraft is currently in its ‘Grand Finale’ phase, the final phase of its long mission.

Over the course of 22 weeks from April 26 to September 15, 2017, Cassini is making a series of dramatic dives between Saturn and its icy rings.

The mission is returning new insights about the interior of the gas giant and the origins of the rings, along with images from closer to Saturn than ever before.

The mission will end with a final plunge into Saturn’s atmosphere on September 15.

Oceans on Saturn’s Moon May Be Habitable For Microbes

Oceans on Saturn’s Moon May Be Habitable For Microbes

The group reports the results in a paper in the April 14 issue of the journal Science. They claim that the only plausible source for the particles detected in Enceladus’ plume is hydrothermal reactions between hot rocks and water at the bottom of the moon’s ocean. They detected the presence of molecular hydrogen and carbon dioxide, which together provide the ingredients necessary for methanogenesis — a biochemical reaction crucial for the survival of microbes that live in the deep-sea regions on Earth. However, according to a commentary by Jeffrey Seewald, a geochemist at Woods Hole Oceanographic Institution in Massachusetts, scientists still have a long way to go before fully understanding the possibility for life underneath the ice of Enceladus.

The Cassini spacecraft, which launched in 1997, reached Saturn’s orbit in 2004. It is now undertaking the final phase of a mission that started in December 2016 to explore Saturn’s rings. The last flyby of the planet is scheduled for April 19. The project will end when the spacecraft falls into Saturn’s atmosphere, probably around September of this year.

Jupiter gets surprisingly complex new portrait

Jupiter gets surprisingly complex new portrait

Scientists are repainting Jupiter’s portrait — scientifically, anyway. NASA’s Juno spacecraft swooped within 5,000 kilometers (3,100 miles) of Jupiter’s cloud tops last August 27. Scientists’ first close-up of the gas giant has unveiled several unexpected details about the planet’s gravity and powerful magnetic fields. They also give a new view of the planet’s auroras and ammonia-rich weather systems.

Researchers need to revamp their view of Jupiter, these findings suggest. They even challenge ideas about how solar systems form and evolve. The findings come from two papers published May 26 in Science.

“We went in with a preconceived notion of how Jupiter worked,” says Scott Bolton. “And I would say we have to eat some humble pie.” Bolton is a planetary scientist who leads the Juno mission. He works at the Southwest Research Institute in San Antonio, Texas.

Scientists thought that beneath its thick clouds, Jupiter would be uniform and boring. Not anymore. “Jupiter is much more complex deep down than anyone anticipated,” Bolton now observes.

One early surprise came from Jupiter’s gravity. Juno measured that gravity from its tug on the spacecraft. The values suggest that Jupiter doesn’t have a solid, compact core. Instead, the core is probably large and diffuse. It could even be as big as half the planet’s radius, Bolton and his colleagues conclude. “Nobody anticipated that,” Bolton notes.

Imke de Pater is a planetary scientist. She works at the University of California, Berkeley and was not involved in the new studies. The new gravity measurements should lead to a better understanding of the planet’s core, she says. But, she adds, doing so will require using some challenging math.

She was more surprised by Jupiter’s magnetic field. It is the strongest of any planet in our solar system. And Juno’s data show that it is almost twice as strong as expected in some spots. Its strength varies. It gets stronger than expected in some areas, weaker in others. These data support the idea that this magnetic field originates from circulating electric currents. Those currents are probably in one of the planet’s outer layers of hydrogen.

Responding to the ‘wind’

A second study looked at how Jupiter’s magnetic field interacts with a stream of charged particles flowing from the sun. Known as the solar wind, these particles affects Jupiter’s auroras, points out John Connerney. An astrophysicist, he led this study with colleagues at NASA’s Goddard Space Flight Center in Greenbelt, Md.

Auroras are brilliant shows of colored light that appear at or near a planet’s poles. (Earth’s auroras are known as the Northern and Southern Lights.) Juno captured Jupiter’s auroras in ultraviolet and infrared light. These images come from wavelengths beyond what the human eye can see. They showed particles falling into the planet’s atmosphere. That is similar to what happens on Earth. But they also showed beams of electrons shooting out from Jupiter’s atmosphere. Nothing like that occurs on Earth.

Bolton’s team described another oddity. Ammonia wells up from the depths of Jupiter’s atmosphere in a strange way. This upwelling resembles a feature on Earth called a Hadley cell. Warm air at our equator rises and creates trade winds, hurricanes and other forms of weather. Jupiter’s ammonia cycling looks similar to this. But Jupiter lacks a solid surface, the researchers note. So the upwelling likely works in a completely different way than on Earth. The scientists hope to figure out how this works on Jupiter. This could help scientists better understand the atmospheres of such huge gas planets.

Explains Bolton, Jupiter is a standard of comparison for all gas giants — both within and beyond our solar system. Most planetary systems have Jupiter-like planets. He says that means researchers can apply what they learn about Jupiter to giant planets elsewhere.

Planet Nine could spell doom for solar system

Planet Nine could spell doom for solar system

The solar system could be thrown into disaster when the sun dies if the mysterious ‘Planet Nine’ exists, according to research from the University of Warwick. Dr Dimitri Veras in the Department of Physics has discovered that the presence of Planet Nine – the hypothetical planet which may exist in the outer Solar System – could cause the elimination of at least one of the giant planets after the sun dies, hurling them out into interstellar space through a sort of ‘pinball’ effect.

When the sun starts to die in around seven billion years, it will blow away half of its own mass and inflate itself — swallowing the Earth — before fading into an ember known as a white dwarf. This mass ejection will push Jupiter, Saturn, Uranus and Neptune out to what was assumed a safe distance.

However, Dr. Veras has discovered that the existence of Planet Nine could rewrite this happy end-ing. He found that Planet Nine might not be pushed out in the same way, and in fact might instead be thrust inward into a death dance with the solar system’s four known giant planets — most notably Uranus and Neptune. The most likely result is ejection from the solar system, forever.

Using a unique code that can simulate the death of planetary systems, Dr. Veras has mapped nu-merous different positions where a ‘Planet Nine’ could change the fate of the solar system. The further away and the more massive the planet is, the higher the chance that the solar system will experience a violent future.

This discovery could shed light on planetary architectures in different solar systems. Almost half of existing white dwarfs contain rock, a potential signature of the debris generated from a similarly calamitous fate in other systems with distant “Planet Nines” of their own.

In effect, the future death of our sun could explain the evolution of other planetary systems.

Dr. Veras explains the danger that Planet Nine could create: “The existence of a distant massive planet could fundamentally change the fate of the solar system. Uranus and Neptune in particular may no longer be safe from the death throes of the Sun. The fate of the solar system would depend on the mass and orbital properties of Planet Nine, if it exists.”

“The future of the Sun may be foreshadowed by white dwarfs that are ‘polluted’ by rocky debris. Planet Nine could act as a catalyst for the pollution. The Sun’s future identity as a white dwarf that could be ‘polluted’ by rocky debris may reflect current observations of other white dwarfs throughout the Milky Way,” Dr Veras adds.

The paper ‘The fates of solar system analogues with one additional distant planet’ will be published in the Monthly Notices of the Royal Astronomical Society.

Scientists Predict a New Star Will Appear in 2022

Scientists Predict a New Star Will Appear in 2022

It’s the first time scientists have been able to predict such an explosion and it happened with the help of a little serendipity. Astronomer Larry Molnar, from Calvin College in Grand Rapids, Michigan, and his students became intrigued with a star known as KIC 9832227 after hearing a talk at an astronomy conference, according to a press release. KIC 9832227, which is about 1,800 light-years away from Earth, kept changing brightness, and close observations revealed that the star was actually two stars orbiting one another so closely their outermost layers touch.

The researchers calculated how long it took the stars to circle each other, and realized the orbit time was getting shorter. The data closely matched that of another star system, V1309 Scorpii, which exploded in 2008.

Molnar’s team thinks KIC 9832227 will follow the same path, producing a “red nova” stellar explosion that will briefly make the system 10,000 times brighter. The “guest star” will have a reddish tint and will appear in a wing of the constellation Cygnus, a swan-shaped collection of stars that grace the northern sky in summer and autumn.

High-Silica ‘Halos’ Found in Gale Crater Shed Light on Wet Ancient Mars

High-Silica ‘Halos’ Found in Gale Crater Shed Light on Wet Ancient Mars

The concentration of silica is very high at the centerlines of these halos,” saidDr. Jens Frydenvang, a scientist at Los Alamos National Laboratory and the University of Copenhagen.

“What we’re seeing is that silica appears to have migrated between very old sedimentary bedrock and into younger overlying rocks.”

“The goal of NASA’s Curiosity rover mission has been to find out if Mars was ever habitable, and it has been very successful in showing that Gale crater once held a lake with water that we would even have been able to drink, but we still don’t know how long this habitable environment endured,” he said.

“What this finding tells us is that, even when the lake eventually evaporated, substantial amounts of groundwater were present for much longer than we previously thought — thus further expanding the window for when life might have existed on Mars.”

Whether this groundwater could have sustained life remains to be seen. But the new study buttresses recent findings by another research team who foundboron on Mars, which also indicates the potential for long-term habitable groundwater in the planet’s past.

The halos were first analyzed in 2015 with Curiosity’s science-instrument payload, including the laser-shooting ChemCam instrument.

The rover has traveled more than 10 miles (16 km) over more than 1,700 sols (Martian days) as it has traveled from the bottom of Gale crater part way up Mount Sharp in the center of the crater.

The elevated silica in halos was found over 65 to 100 feet (20-30 m) in elevation near a rock-layer of ancient lake sediments that had a high silica content.

“This tells us that the silica found in halos in younger rocks close by was likely remobilized from the old sedimentary rocks by water flowing through the fractures,” Dr. Frydenvang said.

“Specifically, some of the rocks containing the halos were deposited by wind, likely as dunes. Such dunes would only exist after the lake had dried up.”

“The presence of halos in rocks formed long after the lake dried out indicates that groundwater was still flowing within the rocks more recently than previously known.”