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Philae discovers organic molecules on comet

by Stephen Clark

Europe’s Philae lander found a surface as hard as ice and organic molecules after it bounced to a stop on a comet last week.

Scientists looking over the spoils from the plucky little Philae probe released some of the first results from the mission Monday after a hectic week of descent preparations, a dramatic landing that included three touchdowns, and more than 60 hours of data gathering.

“We have collected a great deal of valuable data, which could only have been acquired through direct contact with the comet,” said Ekkehard Kuhrt, scientific director for the Philae mission at DLR — the German space agency. “Together with the measurements performed by the Rosetta orbiter, we are well on our way to achieving a greater understanding of comets. Their surface properties appear to be quite different than was previously thought.”

After coming to rest on its side, Philae continued transmitting data intermittently when in range of Rosetta, the European-built orbiter that deployed the refrigerator-sized lander for its descent Wednesday.

Rosetta continues flying around comet 67P/Churyumov-Gerasimenko, with at least another year of observations planned as the icy world moves toward the sun. It will heat up and give off more gas and dust through perihelion — its closest approach to the sun — in August 2015.

Before its battery died, Philae unfurled an instrument boom to study the comet’s surface properties. The MUPUS instrument was designed to hammer into the nucleus about 1.5 meters (about 5 feet) from the lander, and data show the system worked as planned despite Philae’s precarious position lodged against a rocky face at an angle with one leg pointing into space.

“Although the power of the hammer was gradually increased, we were not able to go deep into the surface,” said Tilman Spohn, head of the MUPUS instrument on Philae. “We have acquired a wealth of data, which we must now analyze.”

According to a DLR press release, the MUPUS team estimates the outer skin of the comet’s nucleus — at least where Philae settled after its bouncy landing — is as hard as ice.

“With MUPUS it has been possible to directly study the strength of a comet’s surface for the first time — and 67P/Churyumov-Gerasimenko proved to be a ‘tough nut to crack,’” DLR said in a statement Monday.

The MUPUS sensors were supposed to measure the comet’s temperature, the mechanical properties of its surface, and its thermal conductivity.

Only thermal and acceleration sensors in Philae’s two harpoons were not used, DLR said, because the anchoring system was not deployed during landing.

Data collected by Philae’s SESAME experiment suite support MUPUS results indicating the comet’s unexpected toughness. Early findings also show a low level of cometary activity at the probe’s landing site and a large amount of water ice under the lander, according to DLR.

“The strength of the ice founds under a layer of dust on the first landing site is surprisingly high,” said Klaus Seidensticker from the DLR Institute of Planetary Research, lead scientist on the SESAME instrument package, which was expected to study the comet’s composition and electrical, structural and mechanical characteristics.

On Friday — the lander’s last day of operations — ground controllers sent commands to activate Philae’s drill. The system was designed to collect core samples a few inches deep and deliver the material into two of the lander’s instruments — ovens that would have heated up the bits of rock or ice to measure their make-up.

While officials said Monday it was clear the drill worked, they could not say whether it gathered samples and deposited them in the lander’s instruments.

One of Philae’s sample analysis sensors — named COSAC — did collect data in “sniff” mode and detected organic molecules, presumably outgassing just above the comet’s surface.

Philae’s descent imaging camera was also switched back on and took up-close images of the comet’s nucleus at the lander’s final resting site. The down-facing camera also recorded imagery of Philae’s descent to the craft’s initial landing site before it rebounded to two more touchdowns.

Scientists were also able to use Philae in conjunction with Rosetta to study the comet’s internal structure, DLR said.

“To achieve this, the lander and orbiter were on different sides of the comet and worked together to analyse the comet nucleus by passing radio signals through it and creating a three-dimensional profile of the core,” the DLR statement said.

Scientists are hopeful Philae will recharge its batteries in the coming weeks and months, allowing for the mission to resume as the comet nears the sun.

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Space

Voyager 2 has discovered something amazing: Denser space outside the solar system

In November 2018, after a 41-year voyage, Voyager 2 crossed the boundary beyond which the Sun’s influence ends, and entered interstellar space. But the mission of the little probe is not yet complete – it continues to make amazing discoveries

Perhaps the probes have found some kind of traffic jam at the edge of the solar system. The Voyager flight continues and we will soon find out what it was.

Voyager 2 discovered something amazing: as the distance from the Sun increases, the density of space increases.

Voyager 1, which entered interstellar space in 2012, transmitted similar indicators to Earth. New data have shown that the increase in density may be a feature of the interstellar medium.

The solar system has several boundaries, one of which, called the heliopause, is determined by the solar wind, or rather by its significant weakening. The space inside the heliopause is the heliosphere, and the space outside is the interstellar medium. But the heliosphere is not round. It looks more like an oval, in which the solar system is at the leading edge, and a kind of tail stretches behind it.

Both Voyagers crossed the heliopause at the leading edge, but within 67 degrees heliographic latitude and 43 degrees longitude apart.

Interstellar space is usually considered a vacuum, but this is not entirely true. The density of matter is extremely small, but it still exists. In the solar system, the solar wind has an average density of protons and electrons from 3 to 10 particles per cubic centimeter, but it is lower the further from the Sun.

The average concentration of electrons in the interstellar space of the Milky Way is estimated to be about 0.037 particles per cubic centimeter. And the plasma density in the outer heliosphere reaches approximately 0.002 electrons per cubic centimeter. When the Voyager probes crossed the heliopause, their instruments recorded the electron density of the plasma through plasma oscillations.

Voyager 1 crossed the heliopause on August 25, 2012 at a distance of 121.6 astronomical units from the Earth (121.6 times the distance from Earth to the Sun – about 18.1 billion km). When he first measured plasma oscillations after crossing the heliopause on October 23, 2013 at a distance of 122.6 astronomical units (18.3 billion km), he found a plasma density of 0.055 electrons per cubic centimeter.

After flying another 20 astronomical units (2.9 billion kilometers), Voyager 1 reported an increase in the density of interstellar space to 0.13 electrons per cubic centimeter.

Voyager 2 crossed the heliopause on November 5, 2018 at a distance of 119 astronomical units (17.8 billion kilometers. On January 30, 2019, it measured plasma oscillations at a distance of 119.7 astronomical units (17.9 billion kilometers), finding that the density plasma is 0.039 electrons per cubic centimeter.

In June 2019, Voyager 2’s Instruments showed a sharp increase in density to about 0.12 electrons per cubic centimeter at a distance of 124.2 astronomical units (18.5 billion kilometers).

What caused the increase in the density of space? One theory is that the lines of force of the interstellar magnetic field become stronger with distance from the heliopause. This can cause electromagnetic ion cyclotron instability. Voyager 2 did detect an increase in the magnetic field after crossing the heliopause.

Another theory is that the material carried away by the interstellar wind should slow down in the heliopause, forming a kind of plug, as evidenced by the weak ultraviolet glow detected by the New Horizons probe in 2018, caused by the accumulation of neutral hydrogen in the heliopause.

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Space

NASA has banned fighting and littering on the moon

New details of the agreement signed by representatives of a number of countries on the development of the moon and the extraction of minerals within the framework of the Artemis program have appeared. Reported by the National Aeronautics and Space Administration (NASA).

So, astronauts involved in the mission are prohibited from littering and fighting on the territory of a natural satellite of the Earth.

So, we present to you the new rules for being on the Moon:

Everyone comes in peace;

Confidentiality is prohibited, all launched objects must be identified and registered;

All travel participants agree to help each other in case of emergencies;

All received data is transferred to the rest of the participants, and space systems must be universal;

Historic sites must be preserved and all rubbish must be disposed of;

Rovers and spacecraft should not interfere with other participants.

“”It is important not only to go to the moon with our astronauts, but also that we bring our values ​​with us,” said Mike Gold, acting head of NASA’s international and inter-agency relations.

According to him, violators of the above rules will be asked to “just leave” the territory of the moon.

The effect of these principles so far applies to eight signatory countries of the agreement: the USA, Australia, Canada, Italy, Japan, Luxembourg, the United Arab Emirates and the United Kingdom. Countries other than China can join if they wish.

 It should be noted that at the moment NASA is prohibited from signing any bilateral agreements with the PRC leadership.

The first NASA mission to the moon, known as “Artemis 1”, is scheduled for 2021 without astronauts, and “Artemis 2” will fly with a crew in 2023.

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Space

Methane snow found on the tops of Pluto’s equatorial mountains

Scientists believe that it arose as a result of the accumulation of large amounts of methane at an altitude of several kilometers above the surface of the planet.

In the images of the Cthulhu region – a dark region in the equatorial regions of Pluto – planetary scientists have found large reserves of methane snow that covers the peaks of local mountains and hills. It formed quite differently from how snow forms on Earth, astronomers write in the scientific journal Nature Communications.

“The white caps on the tops of Pluto’s mountains did not arise from the cooling of air currents that rise along the slopes into the upper atmosphere, as it happens on Earth, but from the accumulation of large amounts of methane at an altitude of several kilometers above Pluto’s surface. This gas condensed on the mountain tops, “the scientists write.

We owe almost everything we know about Pluto to the New Horizons interplanetary station. It was launched in January 2006, and in mid-July 2015 the station reached the Pluto system. New Horizons flew just 13 thousand km from the dwarf planet, taking many photographs of its surface. 

New Horizons data indicated an interesting feature of Pluto – in its depths, a giant subglacial ocean of liquid water can be hidden. It can be a kind of engine of those geological processes, traces of which can be seen on the surface of a dwarf planet. Because of this discovery of New Horizons, many discussions began among planetary scientists. Scientists are trying to understand how such a structure could have arisen, as well as to find out the appearance of Pluto in the distant past.

Members of the New Horizons science team and their colleagues from France, led by planetary scientist from NASA’s Ames Research Center (USA) Tanguy Bertrand, have discovered another unusual feature of Pluto. They studied the relief of one of the regions of the dwarf planet – the Cthulhu region. This is what astronomers call a large dark region at Pluto’s equator, which is whale-like in shape and is covered in many craters, mountains and hills.

Snow in Pluto’s mountains

By analyzing images of these structures taken by the LORRI camera installed on board New Horizons, astronomers have noticed many blank spots on the slopes of the highest mountain peaks. Having studied their composition, scientists have found that they consist mainly of methane.

Initially, planetary scientists assumed that these are deposits of methane ice. However, Bertrand and his colleagues found that the slopes and even the tops of Pluto’s equatorial mountains are actually covered not only with ice, but also with exotic methane snow that forms right on their surface.

Planetary scientists came to this conclusion by calculating how methane behaves in Pluto’s atmosphere. In doing so, they took into account how the molecules of its gases interact with the sun’s rays and other heat sources. It turned out that at the equator of Pluto, at an altitude of 2-3 km from its surface, due to the special nature of the movement of winds, unique conditions have formed, due to which snow is formed from methane vapor.

Unlike Earth, where such deposits are formed as a result of the rise of warm air into the upper atmosphere, on Pluto this process goes in the opposite direction – as a result of contact of the cold surface of the peaks and slopes of mountains with warm air masses from the relatively high layers of the dwarf planet’s atmosphere.

Previously, as noted by Bertrand and his colleagues, scientists did not suspect that this was possible. The fact is that they did not take into account that due to the deposition of even a small amount of methane snow and ice, the reflectivity of the peaks and slopes of mountains in the Cthulhu region increases. As a result, their surface temperature drops sharply, and snow forms even faster.

Scientists suggest that another mysterious feature of Pluto’s relief could have arisen in a similar way – the so-called Tartarus Ridges, located east of the Sputnik plain. A distinctive feature of this mountainous region is strange peaks that are shaped like skyscrapers or blades. Bertrand and his colleagues suggest that these peaks are also methane ice deposits that grow “from top to bottom.”

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