Giant particle accelerator in the sky

The Earth's magnetic field is trapping high energy particles. When the first satellites were launched into space, scientists led by James Van Allen unexpectedly discovered the high energy particle radiation regions, which were later named after its discoverer Van Allen Radiation Belts. Visualized, these look like two donut-shaped regions encompassing our planet. Now, a new study led by researchers from GFZ German Research Centre for Geosciences shows that electrons in the radiation belts can be accelerated to very high speeds locally. The study shows that magnetosphere works as a very efficient particle accelerator speeding up electrons to so-called ultra-relativistic energies. The study conducted by Hayley Allison, a postdoctoral scholar at GFZ Potsdam, and Yuri Shprits from GFZ and Professor at the University of Potsdam, is published in Nature Communications. To better understand the origin of the Van Allen Belts, in 2012 NASA launched the Van Allen Probes twin spacecraft to traverse this most harsh environment and conduct detailed measurements in this hazardous region. The measurements included a full range of particles moving at different speeds and in different directions and plasma waves. Plasma waves are similar to the waves that we see on the water surface, but are in fact invisible to the naked eye. They can be compared to ripples in the electric and magnetic field. Recent observations revealed that the energy of electrons in the belts can go up to so called ultra-relativistic energies. These electrons with temperatures above 100 Billion degrees Fahrenheit, move so fast that their energy of motion is much higher than their energy of rest given by Einstein's famous E=mc2 formula. They are so fast that the time flow significantly slows down for these particles.

Scientists were surprised to find these ultra-relativistic electrons and assumed that such high energies can be only reached by a combination of two processes: the inward transport of particles from the outer regions of the magnetosphere, which accelerates them; and a local acceleration of particles by plasma waves.

However, the new study shows that electrons reach such incredible energies locally, in the heart of the belts, by taking all this energy from plasma waves. This process turns out to be extremely efficient.

The unexpected discovery of how acceleration of particles to ultra-relativistic energies operates in the near-Earth space, may help scientists understand the fundamental processes of acceleration on the Sun, near outer planets, and even in the distant corners of the universe where space probes cannot reach.

Study of material surrounding distant stars shows Earth's ingredients 'pretty normal'

The Earth's building blocks seem to be built from 'pretty normal' ingredients, according to researchers working with the world's most powerful telescopes. Scientists have measured the compositions of 18 different planetary systems from up to 456 light years away and compared them to ours, and found that many elements are present in similar proportions to those found on Earth. This is amongst the largest examinations to measure the general composition of materials in other planetary systems, and begins to allow scientists to draw more general conclusions on how they are forged, and what this might mean for finding Earth-like bodies elsewhere. "Most of the building blocks we have looked at in other planetary systems have a composition broadly similar to that of the Earth", said researcher Dr Siyi Xu of the Gemini Observatory in Hawaii, who was presenting the work at the Goldschmidt conference in Boston. The first planets orbiting other stars were only found in 1992 (this was orbiting a pulsar), since then scientists have been trying to understand whether some of these stars and planets are similar to our own solar system. "It is difficult to examine these remote bodies directly. Because of the huge distances involved, their nearby star tends to drown out any electromagnetic signal, such as light or radio waves" said Siyi Xu. "So we needed to look at other methods".

Because of this, the team decided to look at how the planetary building blocks affect signals from white dwarf stars. These are stars which have burnt off most of their hydrogen and helium, and shrunk to be very small and dense - it is anticipated that our Sun will become a white dwarf in around 5 billion years.

Dr Xu continued, "White dwarfs' atmospheres are composed of either hydrogen or helium, which give out a pretty clear and clean spectroscopic signal. However, as the star cools, it begins to pull in material from the planets, asteroids, comets and so on which had been orbiting it, with some forming a dust disk, a little like the rings of Saturn.

"As this material approaches the star, it changes how we see the star. This change is measurable because it influences the star's spectroscopic signal, and allows us to identify the type and even the quantity of material surrounding the white dwarf. These measurements can be extremely sensitive, allowing bodies as small as an asteroid to be detected".

The team took measurements using spectrographs on the Keck telescope in Hawaii, the world's largest optical and infrared telescope, and on the Hubble Space Telescope.

Siyi Xu continued, "In this study, we have focused on the sample of white dwarfs with dust disks. We have been able to measure calcium, magnesium, and silicon content in most of these stars, and a few more elements in some stars. We may also have found water in one of the systems, but we have not yet quantified it: it's likely that there will be a lot of water in some of these worlds. For example, we've previously identified one star system, 170 light years away in the constellation Bootes, which was rich in carbon, nitrogen and water, giving a composition similar to that of Halley's Comet. In general though, their composition looks very similar to bulk Earth.

This would mean that the chemical elements, the building blocks of earth are common in other planetary systems. From what we can see, in terms of the presence and proportion of these elements, we're normal, pretty normal. And that means that we can probably expect to find Earth-like planets elsewhere in our Galaxy".

Dr Xu continued "This work is still on-going and the recent data release from the Gaia satellite, which so far has characterized 1.7 billion stars, has revolutionized the field. This means we will understand the white dwarfs a lot better. We hope to determine the chemical compositions of extrasolar planetary material to a much higher precision"

Professor Sara Seager, Professor of Planetary Science at Massachusetts Institute of Technology, is also the deputy science director of the recently-launched TESS (Transiting Exoplanet Survey Satellite) mission, which will search for exoplanets. She said:

"It's astonishing to me that the best way to study exoplanet interiors is by planets ripped apart and absorbed by their white dwarf host star. It is great to see progress in this research area and to have solid evidence that planets with Earth-like compositions are common--fueling our confidence that an Earth-like planet around a very nearby normal star is out there waiting to be found".

Satellite measurements of the Earth's magnetosphere promise better space weather forecasts

Earth is constantly being hammered by charged particles emitted by the Sun that have enough power to make life on Earth almost impossible. We survive because Earth's magnetic field traps and deflects these particles, preventing the vast majority of them from ever reaching the planet's surface. The trapped particles bounce back and forth between the North and South poles in complex, ever-changing patterns that are also influenced by equally intricate and shifting electric fields. We get to enjoy the sight of those particles when the bands they move in (the Van Allen radiation belts) dip into our atmosphere near the poles creating the Northern (and Southern) lights. However, bursts of these particles can damage satellites and sensitive equipment on the ground. It is therefore vital to understand the intricacies of the radiation belts. So far, NASA have launched twin satellites to study the Van Allen belts--however, their orbits only allow them to explore the equatorial regions. This limits our ability to understand flow of particles and prevents us from predicting their effects on all satellites. To also explore regions further from the equator, the Institute of Space and Astronautical Science, a division of the Japan Aerospace Exploration Agency, launched the Arase satellite in 2016.

A Japan-based research team centered at Kanazawa University equipped the Arase satellite with multiple different sensors (termed the Plasma Wave Experiment) to probe the electric field and plasma waves in the Earth's inner magnetosphere. Now, they have collected their first set of data from their sensors, which they recently published in the Springer journal Earth, Planets and Space.

The Arase consists primarily of electric and magnetic field detectors covering a wide frequency range; it can also measure plasma/particles in a wide energy range. To improve efficiency, an on-board computer studies the correlations between the fields and the particles before sending only the most important information back to Earth.

"The Plasma Wave Experiment equipment has passed initial checks and has successfully acquired high quality data. Huge amount of burst waveform data has been taken, and we should soon know a lot more about mechanisms of wave-particle interaction occurring in the inner magnetosphere than before.

Another strength of our project is that we can also compare the satellite data with data collected simultaneously on the ground. We expect those comparisons will greatly broaden our understanding of this area of science," first author Yoshiya Kasahara says.

Understanding how electrons and other particles are hurled out of the magnetosphere onto our planet could be key to predicting such bursts and protecting against them.

Exoplanets where life could develop as on Earth

Scientists have identified a group of planets outside our solar system where the same chemical conditions that may have led to life on Earth exist. The researchers, from the University of Cambridge and the Medical Research Council Laboratory of Molecular Biology (MRC LMB), found that the chances for life to develop on the surface of a rocky planet like Earth are connected to the type and strength of light given off by its host star. Their study, published in the journal Science Advances, proposes that stars which give off sufficient ultraviolet (UV) light could kick-start life on their orbiting planets in the same way it likely developed on Earth, where the UV light powers a series of chemical reactions that produce the building blocks of life. The researchers have identified a range of planets where the UV light from their host star is sufficient to allow these chemical reactions to take place, and that lie within the habitable range where liquid water can exist on the planet's surface. "This work allows us to narrow down the best places to search for life," said Dr. Paul Rimmer, a postdoctoral researcher with a joint affiliation at Cambridge's Cavendish Laboratory and the MRC LMB, and the paper's first author. "It brings us just a little bit closer to addressing the question of whether we are alone in the universe."

The new paper is the result of an ongoing collaboration between the Cavendish Laboratory and the MRC LMB, bringing together organic chemistry and exoplanet research. It builds on the work of Professor John Sutherland, a co-author on the current paper, who studies the chemical origin of life on Earth.

In a paper published in 2015, Professor Sutherland's group at the MRC LMB proposed that cyanide, although a deadly poison, was in fact a key ingredient in the primordial soup from which all life on Earth originated.

In this hypothesis, carbon from meteorites that slammed into the young Earth interacted with nitrogen in the atmosphere to form hydrogen cyanide. The hydrogen cyanide rained to the surface, where it interacted with other elements in various ways, powered by the UV light from the Sun. The chemicals produced from these interactions generated the building blocks of RNA, the close relative of DNA which most biologists believe was the first molecule of life to carry information.

In the laboratory, Sutherland's group recreated these chemical reactions under UV lamps, and generated the precursors to lipids, amino acids and nucleotides, all of which are essential components of living cells.

"I came across these earlier experiments, and as an astronomer, my first question is always what kind of light are you using, which as chemists they hadn't really thought about," said Rimmer. "I started out measuring the number of photons emitted by their lamps, and then realised that comparing this light to the light of different stars was a straightforward next step."

The two groups performed a series of laboratory experiments to measure how quickly the building blocks of life can be formed from hydrogen cyanide and hydrogen sulphite ions in water when exposed to UV light. They then performed the same experiment in the absence of light.

"There is chemistry that happens in the dark: it's slower than the chemistry that happens in the light, but it's there," said senior author Professor Didier Queloz, also from the Cavendish Laboratory. "We wanted to see how much light it would take for the light chemistry to win out over the dark chemistry."

The same experiment run in the dark with the hydrogen cyanide and the hydrogen sulphite resulted in an inert compound which could not be used to form the building blocks of life, while the experiment performed under the lights did result in the necessary building blocks.

The researchers then compared the light chemistry to the dark chemistry against the UV light of different stars. They plotted the amount of UV light available to planets in orbit around these stars to determine where the chemistry could be activated.

They found that stars around the same temperature as our Sun emitted enough light for the building blocks of life to have formed on the surfaces of their planets. Cool stars, on the other hand, do not produce enough light for these building blocks to be formed, except if they have frequent powerful solar flares to jolt the chemistry forward step by step. Planets that both receive enough light to activate the chemistry and could have liquid water on their surfaces reside in what the researchers have called the abiogenesis zone.

Among the known exoplanets which reside in the abiogenesis zone are several planets detected by the Kepler telescope, including Kepler 452b, a planet that has been nicknamed Earth's 'cousin,' although it is too far away to probe with current technology. Next-generation telescopes, such as NASA's TESS and James Webb telescopes, will hopefully be able to identify and potentially characterise many more planets that lie within the abiogenesis zone.

Of course, it is also possible that if there is life on other planets, that it has or will develop in a totally different way than it did on Earth.

"I'm not sure how contingent life is, but given that we only have one example so far, it makes sense to look for places that are most like us," said Rimmer. "There's an important distinction between what is necessary and what is sufficient. The building blocks are necessary, but they may not be sufficient: it's possible you could mix them for billions of years and nothing happens. But you want to at least look at the places where the necessary things exist."

According to recent estimates, there are as many as 700 million trillion terrestrial planets in the observable universe. "Getting some idea of what fraction have been, or might be, primed for life fascinates me," said Sutherland. "Of course, being primed for life is not everything and we still don't know how likely the origin of life is, even given favourable circumstances - if it's really unlikely then we might be alone, but if not, we may have company."

Preparing to fly the wind mission Aeolus

The launch of Aeolus - ESA's mission to map Earth's wind in real-time - is getting tantalisingly close, with the satellite due for lift-off on 21 August from Europe's Spaceport in Kourou, French Guiana. With the wind in their sails, mission teams are busily preparing this unique satellite for its upcoming journey. Aeolus will carry a sophisticated atmospheric laser Doppler instrument, dubbed Aladin. Combining two powerful lasers, a large telescope and extremely sensitive receivers, it is one of the most advanced instruments ever put into orbit. The spacecraft has already been tested to handle the rigours of space, and recently made a 12-day crossing of the Atlantic from France to Europe's Spaceport in Kourou, French Guiana. Lift-off is set for 21 August at 21:20 GMT (23:20 CEST) on a Vega rocket. "Aeolus' arrival at the launch site marks the end of 16 years of intensive planning, testing and construction, by literally generations of engineers and scientists" says Juan Pineiro, Spacecraft Operations Manager for Aeolus. "We now look forward to seeing the skill and dedication of these countless individuals come to fruition, as Aeolus takes flight and we begin receiving evidence that the satellite can fulfil its very ambitious mission objectives."

The complex world of winds

Currently one of the biggest challenges in making accurate weather predictions is gathering enough information about Earth's wind. Aeolus will be the first-ever satellite to directly measure winds from space, at all altitudes, from Earth's surface through the troposphere and up 30 km to the stratosphere - providing information that will significantly improve the quality of weather forecasts.

Paolo Ferri, Head of Mission Operations at ESA adds, "The Aeolus mission will be a wonderful addition to our fleet of satellites that continually observe Earth bringing us incredible insights into our planet, in particular into the complex world of atmospheric dynamics and climate processes - systems that not only affect our everyday lives but also have huge consequences for our future."

Aeolus will orbit continuously from pole to pole in a so-called 'Sun-synchronous' orbit - passing over any given point on Earth's surface at the same local time each revolution, always maintaining the same orientation in relation to the Sun.

Specifically, Aeolus will follow a 'dawn/dusk' orbit, appearing to follow the borderline between sun and shade, day and night on Earth, meaning its solar panels will always receive the same amount of
light from the Sun.

Simulating every eventuality

In preparation for this unique mission, teams at ESA's European Space Operations Centre have spent months practising to handle any possible scenarios in a series of launch simulations in the centre's Main Control Room.

Once a satellite has been launched into space, it goes through the critical and complex 'launch and early orbit phase', during which control systems and, later, instruments, are progressively switched on and their health and proper functioning assessed.

This is a risky time when the satellite is unusually vulnerable - not yet fully functional but still exposed to the hazards of space.

Pier Paolo Emanuelli, Flight Director for Aeolus, describes this unique period:

"Every satellite has its own unique objectives, orbit and quirks, and Aeolus is no exception. Teams of highly trained engineers, flight dynamics specialists and experts in control systems and ground stations have been practising exactly what Aeolus needs to do, when, and how they will instruct it to do so."

"It's a challenging but very exciting time!"

Airbus and Planet join forces to bring new geospatial products to market

Airbus and Planet have entered into a partnership to facilitate access to each other's data and the co-development of new geospatial solutions, by establishing a framework agreement to explore opportunities for joint cooperation in new and existing markets, product offerings, sales and marketing efforts. Both partners aim at providing a comprehensive suite of global satellite data at multiple temporal and spatial resolutions, and developing new analytic products for a wide range of applications to the benefit of their customers. "By combining our strengths, we will provide a key capability to address all market needs, both in terms of data and value-added products, and to best serve our clients, whatever their industry and their requirements," said Francois Lombard, Director of the Intelligence Business at Airbus Defence and Space. "Airbus and Planet are truly complementary partners. Airbus brings long-standing success in serving reliable, high resolution remote sensing, and Planet brings its unique global coverage and temporal cadence, as well as agile aerospace iteration to get sensors quickly to space," said Will Marshall, CEO and co-founder of Planet. "Together we will be able to deliver sophisticated offerings to fit customer needs across international markets."

The partnership reflects the high-value assets of each provider and their synergies for addressing ever-growing, demanding needs for continuous monitoring and accurate information.

Benefitting from both companies' constellations, customers will have access to the entire Earth's landmass every day at 3m resolution with PlanetScope satellites, as well as to intra-daily sub-meter resolution imagery with Pleiades and SkySat constellations.

In addition, they will also have the capability to order images with resolutions of 1.5m (SPOT 6/7), 5m (Rapideye) and 22m (DMC Constellation). Lastly, TerraSAR-X, TanDEM-X and PAZ radar satellites will allow the acquisition of images regardless of weather and daylight conditions, ensuring access to any place on Earth independent of the cloud coverage.

Planet is an integrated aerospace and data analytics company that operates the largest fleet of Earth-imaging satellites, collecting a massive amount of information daily about our changing planet. Planet designs, builds and operates over 190 satellites, and develops the online software and tools that serves data and information to users making critical decisions.

Moon Colonization: Why do we want it and what technologies do we have?

Scientists are convinced that humankind is capable of turning the Moon into a space outpost: people have cosmodromes, heavy carrier rockets, space modules and lunar rovers. Sputnik reveals what is behind the human desire to conquer space and what challenges colonizers may face on the way. The idea of the Moon's colonization was quite popular during the Cold War era. But in the mid-1970s such projects by the USSR and the US were suspended as travel to the satellite proved very expensive and didn't pursue any concrete goal. But half a century later, the dreams of settling on the Moon have taken over mankind once again. Perhaps, this is due to the high technological level of civilization that needs really ambitious goals as well as the prospects for the development of private space exploration, journalist and scientific observer Tatyana Pichugina wrote for Sputnik. According to her, the arsenal of the world's space industry has everything one needs to conquer the Moon. What is missing, are clearly formulated goals.

How Can We Use the Moon?

Many scientists believe that space expansion is a logical step towards mankind's further development.

Sooner or later, Earth will become too "crowded" and there will be a need for a transshipment base on the Moon, from where one could go to Mars and other planets of the solar system.

Moon colonization would also give people an opportunity to extract valuable minerals. Particular hopes are associated with helium-3, which is used in neutron counters.

There is very little helium-3 available on the Earth, but quite a lot - on the Moon. Therefore, a number of governments have already signaled their readiness to go to the satellite to mine helium-3 as a fuel supply.

The possibility of transferring energy-intensive production to the Moon in order to reduce industrial emissions on Earth in the distant future has also been voiced by a number of researchers.

What Challenges Are We About to Face?

There is no atmosphere and no magnetic field on the Moon. Its surface is continuously bombarded with micrometeorites, while the temperature differences during one day may reach two hundred degrees Celsius.

People can work there only in suits and within sealed lunar rovers, or in a stationary inhabited module with a complete life support system.

Generally, the whole construction process must be also based on completely different and advanced technologies: using inflatable modules, producing many building elements on a 3D printer, creating composite materials from the lunar regolith by means of laser sintering.

Thus, there are many things that scientists still have to think through before any actual colonization efforts will take place.

Concrete Projects

A moon-orbiting space station is considered a logical step on the way to the colonization of the moon.

The United States, Russia and China have already announced the implementation of a corresponding project by 2025-2030.

In particular, the US and Russia have agreed on the establishment of a joint orbital station called the Deep Space Gateway. The project may be joined by China, India and some BRICS countries.

Technical details are expected to be presented this year. Construction works in orbit are set to start in 2024.

Giant solar tornadoes put researchers in a spin

Despite their appearance solar tornadoes are not rotating after all, according to a European team of scientists. A new analysis of these gigantic structures, each one several times the size of the Earth, indicates that they may have been misnamed because scientists have so far only been able to observe them using 2-dimensional images. Dr Nicolas Labrosse will present the work, carried out by researchers at the University of Glasgow, Paris Observatory, University of Toulouse, and Czech Academy of Sciences, at the European Week of Astronomy and Space Science (EWASS) in Liverpool on Friday 6 April. Solar tornadoes were first observed in the early 20th century, and the term was re-popularised a few years ago when scientists looked at movies obtained by the AIA instrument on the NASA Solar Dynamics Observatory (SDO). These show hot plasma in extreme ultraviolet light apparently rotating to form a giant structure taking the shape of a tornado (as we know them on Earth). Now, using the Doppler effect to add a third dimension to their data, the scientists have been able to measure the speed of the moving plasma, as well as its direction, temperature and density. Using several years' worth of observations, they were able to build up a more complete picture of the magnetic field structure that supports the plasma, in structures known as prominences.

Dr Nicolas Labrosse, lead scientist in the study, explains: "We found that despite how prominences and tornadoes appear in images, the magnetic field is not vertical, and the plasma mostly moves horizontally along magnetic field lines. However we see tornado-like shapes in the images because of projection effects, where the line of sight information is compressed onto the plane of the sky."

Dr Arturo Lopez Ariste, another member of the team, adds: "The overall effect is similar to the trail of an aeroplane in our skies: the aeroplane travels horizontally at a fixed height, but we see that the trail starts above our heads and ends up on the horizon. This doesn't mean that it has crashed!"

Giant solar tornadoes - formally called tornado prominences - have been observed on the Sun for around a hundred years. They are so called because of their striking shape and apparent resemblance to tornadoes on Earth, but that is where the comparison ends.

Whereas terrestrial tornadoes are formed from intense winds and are very mobile, solar tornadoes are instead magnetized gas. They seem to be rooted somewhere further down the solar surface, and so stay fixed in place.

"They are associated with the legs of solar prominences - these are beautiful concentrations of cool plasma in the very hot solar corona that can easily be seen as pink structures during total solar eclipses," adds Labrosse.

"Perhaps for once the reality is less complicated than what we see!" comments Dr Brigitte Schmieder, another scientist involved in the work.

She continues: "Solar tornadoes sound scary but in fact they normally have no noticeable consequences for us. However, when a tornado prominence erupts, it can cause what's known as space weather, potentially damaging power, satellite and communication networks on Earth."