Mars has metal in its atmosphere, reveals NASA probe

Mars has electrically charged metal atoms (ions) high in its atmosphere, according to new results from NASA’s MAVEN spacecraft. The metal ions can reveal previously invisible activity in the mysterious electrically charged upper atmosphere (ionosphere) of Mars.

“MAVEN has made the first direct detection of the permanent presence of metal ions in the ionosphere of a planet other than Earth,” said Joseph Grebowsky of NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “Because metallic ions have long lifetimes and are transported far from their region of origin by neutral winds and electric fields, they can be used to infer motion in the ionosphere, similar to the way we use a lofted leaf to reveal which way the wind is blowing.” Grebowsky is lead author of a paper on this research appearing April 10 in Geophysical Research Letters.

MAVEN (Mars Atmosphere and Volatile Evolution Mission) is exploring the Martian upper atmosphere to understand how the planet lost most of its air, transforming from a world that could have supported life billions of years ago into a cold desert planet today. Understanding ionospheric activity is shedding light on how the Martian atmosphere is being lost to space, according to the team.

The metal comes from a constant rain of tiny meteoroids onto the Red Planet. When a high-speed meteoroid hits the Martian atmosphere, it vaporizes. Metal atoms in the vapor trail get some of their electrons torn away by other charged atoms and molecules in the ionosphere, transforming the metal atoms into electrically charged ions.

MAVEN has detected iron, magnesium, and sodium ions in the upper atmosphere of Mars over the last two years using its Neutral Gas and Ion Mass Spectrometer instrument, giving the team confidence that the metal ions are a permanent feature. “We detected metal ions associated with the close passage of Comet Siding Spring in 2014, but that was a unique event and it didn’t tell us about the long-term presence of the ions,” said Grebowsky.

The interplanetary dust that causes the meteor showers is common throughout our solar system, so it’s likely that all solar system planets and moons with substantial atmospheres have metal ions, according to the team.

Sounding rockets, radar and satellite measurements have detected metal ion layers high in the atmosphere above Earth. There’s also been indirect evidence for metal ions above other planets in our solar system. When spacecraft are exploring these worlds from orbit, sometimes their radio signals pass through the planet’s atmosphere on the way to Earth, and sometimes portions of the signal have been blocked. This has been interpreted as interference from electrons in the ionosphere, some of which are thought to be associated with metal ions. However, long-term direct detection of the metal ions by MAVEN is the first conclusive evidence that these ions exist on another planet and that they are a permanent feature there.

The team found that the metal ions behaved differently on Mars than on Earth. Earth is surrounded by a global magnetic field generated in its interior, and this magnetic field together with ionospheric winds forces the metal ions into layers. However, Mars has only local magnetic fields fossilized in certain regions of its crust, and the team only saw the layers near these areas. “Elsewhere, the metal ion distributions are totally unlike those observed at Earth,” said Grebowsky.

The research has other applications as well. For example it is unclear if the metal ions can affect the formation or behavior of high-altitude clouds. Also, detailed understanding of the meteoritic ions in the totally different Earth and Mars environments will be useful for better predicting consequences of interplanetary dust impacts in other yet-unexplored solar system atmospheres. “Observing metal ions on another planet gives us something to compare and contrast with Earth to understand the ionosphere and atmospheric chemistry better,” said Grebowsky.

Source: onlinelibrary.wiley.com

Micro spacecraft investigates cometary water mystery

In September 2015, a team of astronomers from the National Astronomical Observatory of Japan, University of Michigan, Kyoto Sangyo University, Rikkyo University and the University of Tokyo successfully observed the entire hydrogen coma of the comet 67P/Churyumov-Gerasimenko, using the LAICA telescope onboard the PROCYON spacecraft. They also succeeded in obtaining the absolute rate of water discharge from the comet.

This comet was the target of ESA’s Rosetta mission in 2015. Because the Rosetta spacecraft was actually inside the cometary coma, it couldn’t observe the overall coma structure. There were bad observing conditions during the time the comet could be observed from Earth, so through our observations, we were able to test the coma models for the comet for the first time.

Comet observation by the PROCYON spacecraft had not been scheduled in the original mission plan. Thanks to the efforts of the spacecraft and telescope operation teams, observations were conducted shortly after we started discussing the possibility, producing results of great scientific importance.

This result is the first scientific achievement by a micro spacecraft for deep space exploration. Moreover, this provides an ideal example where observations by a low-cost mission (e.g., the PROCYON mission) support precise observations by a large mission (e.g., the Rosetta mission). We hope this will become a model case for micro spacecraft observations in support of large missions.

The Rosetta mission and its limits        

The 2015 apparition (appearance) of the comet 67P/Churyumov-Gerasimenko was a target of ESA’s Rosetta mission. In the Rosetta mission, precise observations of the comet were carried out from close to the surface of the nucleus for more than two years including when the comet passed perihelion (closest approach to the Sun) on August 13, 2015. However, observation of the entire coma was difficult because the Rosetta spacecraft was located in the cometary coma.

To extrapolate from Rosetta’s observations of specific areas and estimate the total amount of water released by the comet per second (water production rate), we need a model for the coma. But the water production rate strongly depends on the coma model we use. To test the coma models, we have to compare the absolute water production rate derived from entire coma observations to predictions based on Rosetta’s results and the various coma models. Therefore, it was useful to observe the entire coma from farther away from the comet with another satellite.

Conventionally, the SWAN telescope onboard the SOHO spacecraft has often been used to observe such targets. Unfortunately, the comet moved to a region where there are many stars behind it, and because of the SWAN telescope’s low spatial-resolution it could not distinguish the comet from the background stars.

Largest full moon in many people’s lifetime is about to shine

On November 14 going to witnesses the Biggest, brightest supermoon to ever grace the skies.

Supermoon occurs when the moon is not only full, but it is orbiting close to earth. This month’s full moon will be the closest to Earth since January 26, 1948.

If the weather is clear, the moon will be at its biggest and brightest in nearly 70 years, and it won’t put on a similar display until late 2034, astronomers say.

Calling the moon Extra-supermoon, Astronomers explain why it is so

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“Since the moon has an elliptical orbit, one side of the orbit (the perigee) is about 48,000 kms closer to Earth than the other side (the apogee). When the Earth, moon and sun line up in an orbit, while the moon is on its nearest approach to Earth, we are treated to a so-called supermoon.

Although this happens three times this year: on October 16, November 14 and on December 14. But the one happens on the November 14 becomes full just two hours after its closest approach to Earth.

When the Sun, the Moon, and Earth line up as the Moon orbits Earth, that’s known as syzygy (definitely something you want to keep in your back pocket for your next Scrabble match).

When this Earth-Moon-Sun system occurs with the perigee side of the Moon facing us, and the Moon happens to be on the opposite side of Earth from the Sun, we get what’s called a perigee-syzygy.

That causes the Moon to appear much bigger and brighter in our sky than usual, and it’s referred to as a supermoon – or more technically, a perigee moon.

 

New Moon Craters Are Forming More Faster Than Scientist Had Predicated

A new study by the Scientists from the Arizon State University and the Cornell University shows that the new moon craters are appearing on the lunar surface 100 times more frequently than previous thought.

Researchers have used images from the Lunar Reconnaissance Orbiter Camera, which is installed on NASA’s Lunar Reconnaissance Orbiter and controlled from the Science Operations Center, within the ASU.

It is reported through a journal Nature that a team led by Emerson Spreyerer, have identified 222 new Moon craters since the Lunar Reconnaissance Orbiter was launched in 2009. They are, of course, impact craters, resulted from multiple meteors that frequently collide with Earth’s only satellite.

It is also estimated that comets and asteroids crash on the lunar surface to create an average of 180 new moon craters every year, which measures at least 10 meters in diameter. The study was based on 14,000 pairs of “before and after’ images.

Moreover, researchers also discovered thousands of “scars” on the moon created by secondary impacts that churned up the top layer of the lunar surface without craters over a period of thousands of years.

Subsurface Ocean Discovered on Saturn’s Moon Dione

I think of space not as the final frontier but as the next frontier. Not as something to be conquered but to be explored. As Humans explore space more deeply and thoroughly, we’re discovering that lot of stuff out is the sloshing.
According to new data from the Cassini Mission to Saturn, Dione, one of the Saturn’s many moons, is the latest celestial body suspected of harboring a subsurface ocean of water. It also suggests that 62 miles below Dione’s crust is an ocean a few miles deep, submerging a rocky core.
“The contact between the ocean and the rocky core is crucial,” said Attilio Rivoldini, co-author of the study.
“Rock-water interactions provide key nutrients and a source of energy, both being essential ingredients for life,” Rivoldini noted.
If confirmed, this would make Dione the third of Saturn’s moons found to harbor oceans under their surface, joining Titan and Enceladus in that increasingly less-exclusive group. It would also suggest that the subsurface waters have likely persisted throughout the moon’s history, meaning that Dione may be home to a long-term habitable zone for microbial life.