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Scientists detect radio emission from a nearby ultra-cool brown dwarf

Scientists detect radio emission from a nearby ultra-cool brown dwarf | Amazing Science | Scoop.it

Located some 23 light years away, the brown dwarf designated WISEP J060738.65+242953.4 or W0607+24 for short, turns out to be a source of radio emission. According to a research paper published July 4, this substellar object showcases quiescent radio emission, making it one of the most radio-faint, ultra-cool dwarfs yet detected.

 

Brown dwarfs like W0607+24 are objects that are too large to be called planets and too small to be stars. With a mass below that necessary to maintain hydrogen-burning nuclear fusion reactions, they are much cooler and dimmer than main sequence stars. These objects could be also sources of radio emission, but the cause of this process is still not completely understood.

 

Due to its proximity, W0607+24 is an excellent target for studying the nature of brown dwarfs. It is the nearest known late-L dwarf in the northern hemisphere, and the third-nearest in the whole sky, allowing researchers to study phenomena occurring in brown dwarfs.

 

That's why a team of astronomers, led by John Gizis of the University of Delaware, Newark, carried out a series of mid-infrared, radio, and optical observations of W0607+24 to study any activity in this curious substellar object. Motivated by the results from NASA's prolonged Kepler mission, named K2, which obtained long time-series photometry of W0607+24, they observed this object simultaneously with the Karl G. Jansky Very Large Array (VLA) in New Mexico and NASA's Spitzer Space Telescope.

 

The most important results were provided by VLA, as the team found that W0607+24 is a source of quiescent, non-bursting, radio emission. The scientists noted that the discovery of this process in this nearby object could be crucial for our understanding of this process in ultracool dwarfs in general.

 

"W0607+24 is a valuable test case for understanding the mechanisms of radio emission in ultracool dwarfs. Some of the radio-detected objects emit rapid, intense bursts with high circular polarization, often found to occur periodically and attributed to coherent emission due to the electron cyclotron maser instability," the paper reads.

 

The astronomers also suggested that the relative radio faintness of W0607+24 may be due to its orientation if the emission is concentrated at the poles. However, follow-up observations are needed to better characterize the detected radio emission and to eliminate all the uncertainties. The team also hopes for more significant findings when studying this nearby substellar object in the future.

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Could a space-based solar farm become a reality by 2040?

Could a space-based solar farm become a reality by 2040? | Amazing Science | Scoop.it

It was just over 40 years ago that the concept of a solar power satellite (SPS) first emerged. American scientist and aerospace engineer Dr. Peter Glaser won a patent for a broadcast system using a one-square kilometer antenna to channel power via microwaves to a receiver on the ground. The advantage of such a system, and space-based solar power in general, is that it harnesses the unobstructed output of the sun, unlike land-based solar systems which are affected by the weather and Earth's day/night cycle.

 

While Glaser's proposal never got off the ground, it did inspire further investigation of the potential of space-based solar power by various government departments and institutions. In 2008, a company called Space Energy conducted a long-range wireless power transmission test using a microwave beam between two Hawaiian islands, a distance of 148 km (91.96 mi). The result was a power yield of 1/1000th of one percent on the receiving end, raising questions over whether the technique could be employed over the much larger distance between a satellite in geosynchronous Earth orbit (GEO) and a ground station.

 

Writing in IEEE Spectrum, Professor Emeritus at JAXA, Susumi Sasaki, argues that this experiment failed largely due to the dense atmosphere disturbing the microwaves' phases as a result of the horizontal transmission. In detailing the agency's proposal he emphasized that in a space-based system the microwaves only need to pass through this dense atmosphere for the last few kilometers of their journey. This, along with new designs for the solar power satellites and anticipated advances in technology over the coming decades, gives JAXA confidence that it can eventually achieve an effective wireless transmission of solar energy over the necessary 36,000 km (22,500 miles) from GEO.

 

JAXA is working on two concepts. The simpler one involves a huge square panel that measures 2 km (1.24 mi) per side. The top surface would be covered with photovoltaic elements, with transmission antennas on the bottom side. A small bus housing controls and communication systems would be tethered to the panel via 10 km (6.2 mi) long wires. A limitation with this design is that the orientation of the panel is fixed, meaning that as the Earth and the satellite spin, the amount of sunlight the panel receives will vary, impacting its ability to generate power.


Via Tania Gammage
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Gaseous - dark - metallic liquid: Probing giant planets’ hydrogen layers

Gaseous - dark - metallic liquid: Probing giant planets’ hydrogen layers | Amazing Science | Scoop.it

Hydrogen is the most-abundant element in the universe. It's also the simplest--sporting only a single electron in each atom. But that simplicity is deceptive, because there is still so much we have to learn about hydrogen.

 

One of the biggest unknowns is its transformation under the extreme pressures and temperatures found in the interiors of giant planets, where it is squeezed until it becomes liquid metal, capable of conducting electricity. New work published in Physical Review Letters by Carnegie's Alexander Goncharov and University of Edinburgh's Stewart McWilliams measures the conditions under which hydrogen undergoes this transition in the lab and finds an intermediate state between gas and metal, which they're calling "dark hydrogen."

 

On the surface of giant planets like Jupiter, hydrogen is a gas. But between this gaseous surface and the liquid metal hydrogen in the planet's core lies a layer of dark hydrogen, according to findings gleaned from the team's lab mimicry. Using a laser-heated diamond anvil cell to create the conditions likely to be found in gas giant planetary interiors, the team probed the physics of hydrogen under a range of pressures from 10,000 to 1.5 million times normal atmospheric pressure and up to 10,000 degrees Fahrenheit. They discovered this unexpected intermediate phase, which does not reflect or transmit visible light, but does transmit infrared radiation, or heat.

 

"This observation would explain how heat can easily escape from gas giant planets like Saturn," explained Goncharov. They also found that this intermediate dark hydrogen is somewhat metallic, meaning it can conduct an electric current, albeit poorly. This means that it could play a role in the process by which churning metallic hydrogen in gas giant planetary cores produces a magnetic field around these bodies, in the same way that the motion of liquid iron in Earth's core created and sustains our own magnetic field.

 

"This dark hydrogen layer was unexpected and inconsistent with what modeling research had led us to believe about the change from hydrogen gas to metallic hydrogen inside of celestial objects," Goncharov added.

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Earth-like Planets Have Earth-like Interiors

Earth-like Planets Have Earth-like Interiors | Amazing Science | Scoop.it

Every school kid learns the basic structure of the Earth: a thin outer crust, a thick mantle, and a Mars-sized core. But is this structure universal? Will rocky exoplanets orbiting other stars have the same three layers? New research suggests that the answer is yes - they will have interiors very similar to Earth. "We wanted to see how Earth-like these rocky planets are. It turns out they are very Earth-like," says lead author Li Zeng of the Harvard-Smithsonian Center for Astrophysics (CfA).

 

To reach this conclusion Zeng and his co-authors applied a computer model known as the Preliminary Reference Earth Model (PREM), which is the standard model for Earth's interior. They adjusted it to accommodate different masses and compositions, and applied it to six known rocky exoplanets with well-measured masses and physical sizes.

 

They found that the other planets, despite their differences from Earth, all should have a nickel/iron core containing about 30 percent of the planet's mass. In comparison, about a third of the Earth's mass is in its core. The remainder of each planet would be mantle and crust, just as with Earth.

 

"We've only understood the Earth's structure for the past hundred years. Now we can calculate the structures of planets orbiting other stars, even though we can't visit them," adds Zeng.

 

The new code also can be applied to smaller, icier worlds like the moons and dwarf planets in the outer solar system. For example, by plugging in the mass and size of Pluto, the team finds that Pluto is about one-third ice, mostly water ice but also ammonia and methane ice varieties.

 

The model assumes that distant exoplanets have chemical compositions similar to Earth. This is reasonable based on the relevant abundances of key chemical elements like iron, magnesium, silicon, and oxygen in nearby systems. However, planets forming in more or less metal-rich regions of the galaxy could show different interior structures. The team expects to explore these questions in future research.

 

The paper detailing this work, authored by Li Zeng, Dimitar Sasselov, and Stein Jacobsen (Harvard University), has been accepted for publication in The Astrophysical Journal and is available online.

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'Space tsunami' causes the third Van Allen Belt

'Space tsunami' causes the third Van Allen Belt | Amazing Science | Scoop.it

Earth's magnetosphere, the region of space dominated by Earth's magnetic field, protects our planet from the harsh battering of the solar wind.

 

Announced recently in Nature Physics, a new discovery led by researchers at the University of Alberta shows for the first time how the puzzling third Van Allen radiation belt is created by a "space tsunami." Intense so-called ultra-low frequency (ULF) plasma waves, which are excited on the scale of the whole magnetosphere, transport the outer part of the belt radiation harmlessly into interplanetary space and create the previously unexplained feature of the third belt.

 

"Remarkably, we observed huge plasma waves," says Ian Mann, physics professor at the University of Alberta, lead author on the study and former Canada Research Chair in Space Physics. "Rather like a space tsunami, they slosh the radiation belts around and very rapidly wash away the outer part of the belt, explaining the structure of the enigmatic third radiation belt."

 

The research also points to the importance of these waves for reducing the space radiation threat to satellites during other space storms as well. "Space radiation poses a threat to the operation of the satellite infrastructure upon which our twenty-first century technological society relies," adds Mann. "Understanding how such radiation is energized and lost is one of the biggest challenges for space research."

 

For the last 50 years, and since the accidental discovery of the Van Allen belts at the beginning of the space age, forecasting this space radiation has become essential to the operation of satellites and human exploration in space.

 

The Van Allen belts, named after their discoverer, are regions within the magnetosphere where high-energy protons and electrons are trapped by Earth's magnetic field. Known since 1958, these regions were historically classified into two inner and outer belts. However, in 2013, NASA's Van Allen Probes reported an unexplained third Van Allen belt that had not previously been observed. This third Van Allen belt lasted only a few weeks before it vanished, and its cause remained inexplicable.

 

Mann is co-investigator on the NASA Van Allen Probes mission. One of his team's main objectives is to model the process by which plasma waves in the magnetosphere control the dynamics of the intense relativistic particles in the Van Allen belts—with one of the goals of the Van Allen Probes mission being to develop sufficient understanding to reach the point of predictability. The appearance of the third Van Allen belt, one of the first major discoveries of the Van Allen Probes era, had continued to puzzle scientists with ever increasingly complex explanation models being developed. However, the explanation announced today shows that once the effects of these huge ULF waves are included, everything falls into place.

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Three Potentially Habitable Worlds Found Around Nearby Ultracool Dwarf Star

Three Potentially Habitable Worlds Found Around Nearby Ultracool Dwarf Star | Amazing Science | Scoop.it

Astronomers using the TRAPPIST telescope at ESO’s La Silla Observatory have discovered three planets orbiting an ultracool dwarf star just 40 light-years from Earth. These worlds have sizes and temperatures similar to those of Venus and Earth and are the best targets found so far for the search for life outside the Solar System. They are the first planets ever discovered around such a tiny and dim star. The new results will be published in the journal Nature on 2 May 2016.

 

A team of astronomers led by Michaël Gillon, of the Institut d’Astrophysique et Géophysique at the University of Liège in Belgium, have used the Belgian TRAPPIST telescope [1] to observe the star 2MASS J23062928-0502285, now also known as TRAPPIST-1. They found that this dim and cool star faded slightly at regular intervals, indicating that several objects were passing between the star and the Earth [2]. Detailed analysis showed that three planets with similar sizes to the Earth were present.

 

TRAPPIST-1 is an ultracool dwarf star — it is much cooler and redder than the Sun and barely larger than Jupiter. Such stars are both very common in the Milky Way and very long-lived, but this is the first time that planets have been found around one of them. Despite being so close to the Earth, this star is too dim and too red to be seen with the naked eye or even visually with a large amateur telescope. It lies in the constellation of Aquarius (The Water Carrier).

 

Emmanuël Jehin, a co-author of the new study, is excited: “This really is a paradigm shift with regards to the planet population and the path towards finding life in the Universe. So far, the existence of such ‘red worlds’ orbiting ultra-cool dwarf stars was purely theoretical, but now we have not just one lonely planet around such a faint red star but a complete system of three planets!”

 

Michaël Gillon, lead author of the paper presenting the discovery, explains the significance of the new findings: "Why are we trying to detect Earth-like planets around the smallest and coolest stars in the solar neighbourhood? The reason is simple: systems around these tiny stars are the only places where we can detect life on an Earth-sized exoplanet with our current technology. So if we want to find life elsewhere in the Universe, this is where we should start to look."

 

Astronomers will search for signs of life by studying the effect that the atmosphere of a transiting planet has on the light reaching Earth. For Earth-sized planets orbiting most stars this tiny effect is swamped by the brilliance of the starlight. Only for the case of faint red ultra-cool dwarf stars — like TRAPPIST-1 — is this effect big enough to be detected.

 

Follow-up observations with larger telescopes, including the HAWK-I instrument on ESO’s 8-metre Very Large Telescope in Chile, have shown that the planets orbiting TRAPPIST-1 have sizes very similar to that of Earth. Two of the planets have orbital periods of about 1.5 days and 2.4 days respectively, and the third planet has a less well determined period in the range 4.5 to 73 days.

 

"With such short orbital periods, the planets are between 20 and 100 times closer to their star than the Earth to the Sun. The structure of this planetary system is much more similar in scale to the system of Jupiter’s moons than to that of the Solar System," explains Michaël Gillon.

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Some Exoplanets May Be Much Smaller than Thought, New Study Says

Some Exoplanets May Be Much Smaller than Thought, New Study Says | Amazing Science | Scoop.it
Cloud or haze layers in the upper atmospheres of extrasolar planets may make them appear bigger than they really are, a study led by Dr. Helmut Lammer from the Austrian Academy of Sciences’ Space Research Institute suggests.

 

Since the first confirmed discovery in 1993, astronomers have found more than 3,000 extrasolar planets. A key goal now is to characterize known planets by mass, size and composition, to better understand the evolution of planetary systems, and the prospects for terrestrial planets that might support life.

 

In 2014 Dr. Lammer and his colleagues used ESA’s CoRoT (Convection, Rotation and planetary Transits) space telescope to study the upper atmosphere of two low-mass exoplanets that are regularly seen to pass in front of their parent star. The two planets, CoRoT-24b and CoRoT-24c, orbit the star in 5 and 12 days, appear to be 3.7 and 4.9 times the diameter of the Earth, and have respective masses of 5.7 and 28 times Earth.

 

CoRoT-24c is similar in mass to Neptune. CoRoT-24b is less than a quarter as massive, but is similar in size, so seems to have a very low density. With such short orbits, both planets are close to and will experience dramatic heating from their star, CoRoT-24.

 

Dr. Lammer’s team modeled this and found that CoRoT-24b would see its atmosphere evaporate within 100 million years, if it really is as big as suggested. But the star is billions of years old, so the planet should have lost its atmosphere long ago. The solution seems to be that CoRoT-24b is only about half as big as thought.

 

Dr. Lammer argues that an extended, very thin, atmosphere, surrounds a relatively compact planet, but has high altitude features that confuse observations. “The radius is based on what we see when the planet makes its transit,” Dr. Lammer said. “This is probably distorted by clouds and haze high in the atmosphere, in a region where atmospheric pressure is otherwise very low.”

 

“This effect needs to be considered by future exoplanet missions, like ESA’s CHEOPS (CHaracterising ExOPlanet Satellite) mission due to launch in December 2017. Results for some worlds found by NASA’s Kepler space telescope may also need to be re-evaluated,” said co-author Dr. Luca Fossati, also from the Space Research Institute.

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Ancient galaxy holds oldest oxygen in universe

Ancient galaxy holds oldest oxygen in universe | Amazing Science | Scoop.it

One of the oldest known galaxies in the universe is now home to the oldest oxygen yet spotted, a new study suggests. That massive group of stars, dubbed SXDF-NB1006-2, lies about 13.1 billion light-years from Earth and was the oldest known galaxy when it was discovered in 2012 (a record that has been toppled several times since). When first observed, astronomers also discerned that the galaxy had a halo of ionized hydrogen (purple in the artist’s sketch above), a sign that radiation streaming from the galaxy’s stars was energetic enough to strip electrons from atoms in that region of space.

 

Now, new observations of a particular wavelength of infrared light from that galaxy betrays the presence of oxygen atoms that have two electrons missing (in the smaller region depicted in green), researchers report online today in Science. Because all elements in the universe heavier than hydrogen, helium, and lithium have been forged by nuclear fusion in the cores of stars and then scattered into space by supernova explosions, the find indicates that the galaxy, at the age we’re now observing it, was old enough for at least one generation of stars to have formed, lived, and died.

 

The lack of infrared glow from the galaxy across a broad range of wavelengths, however, suggests that there’s very little dust there to absorb and then re-radiate the stars’ radiation, the team notes. There are likely many other galaxies of the same age sporting haloes of oxygen, the team notes, and detecting and then analyzing them will help shed light on how stars and galaxies formed and evolved in the early universe.

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Scientists discover humongous, real-life 'Tatooine' planet

Scientists discover humongous, real-life 'Tatooine' planet | Amazing Science | Scoop.it
It's unlikely to contain life, but the Jupiter-sized planet is the largest real-life version of Tatooine, the fictional world that boasts two suns from 'Star Wars.'

 

Astronomers say they’ve found another real-life version of Tatooine, the fictional world from “Star Wars” that features two suns, and it’s the largest one yet. The new planet is indeed far, far away – 3,700 light-years – and approximately 4.4 billion years old, about the same age as Earth. It’s about the same size as Jupiter, making it the largest planet orbiting two suns ever identified.

 

The newly found discovery, uncovered with the help of the Kepler telescope and known as Kepler-1647b, was identified by a team led by researchers at NASA and San Diego State University. It was presented Monday during a meeting of the American Astronomical Society in San Diego.

 

“It’s a bit curious that this biggest planet took so long to confirm, since it is easier to find big planets than small ones,” San Diego State astronomer Jerome Orosz, who worked on the study, said in a statement. The researchers say the planet takes 1,107 days, or just over three years, to orbit its two suns, the longest period discovered so far.

 

It is also located much further away from its host stars than other circumbinary planets, as those with two suns are called. The unusual orbit also puts it in what’s known as the habitable zone, where life-sustaining water can be in liquid form. But its large size makes it an unlikely candidate to support life, the researchers say. But binary star systems could theoretically play host to Earth-like, rocky planets as well, a pair of astrophysicists argued in a paper last year

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Hydrogen signal from 5 billion light years distant galaxy detected

Hydrogen signal from 5 billion light years distant galaxy detected | Amazing Science | Scoop.it
A faint signal of hydrogen has been detected from a galaxy more than five billion light years away in a discovery that will push the boundaries of astronomy forward, a Perth-based radio astronomer says.

 

The detection of a faint signal of hydrogen from a galaxy more than five billion light years away will push the boundaries of astronomy forward, a Perth-based radio astronomer says.

Dr Attila Popping, from the University of Western Australia, is part of the International Centre for Radio Astronomy Research (ICRAR) team, which made the discovery.

 

The team analysed data collected by the Karl G Jansky Very Large Array (VLA) telescope in the US state of New Mexico, and observed emissions from a distant galaxy that would have contained billions of large stars surrounded by clouds of hydrogen gas.

 

The five-billion-light-year distance is almost double that of the previous record for the detection of neutral hydrogen (HI).

Dr Popping said the find would assist scientists in understanding the evolution of galaxies.

 

"Hydrogen is the basic element in the universe. That's where everything had to start," he said. "It's the first building block of gas and stars and galaxies. So with the survey we tried to understand the evolution of HI. How it evolves over time.

 

"By being able to look back over time, and look far away, we can get an image of the universe as it was - five billion years ago in this case - and try to understand how HI evolves and how this affects galaxy formation in general. "What triggers star formation and those sort of things."

 

He said the discovery was like looking into the past, with the hydrogen long since expired. "The hydrogen has probably been turned into stars," he said. "It's been eaten by the galaxy and become a supernova explosion and expelled again. The gas itself is probably in a different state now, than as we can see it."

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California expert explains what we know about the mysterious Planet Nine

California expert explains what we know about the mysterious Planet Nine | Amazing Science | Scoop.it

The theory is that our sun, in its youth some 4.5 billion years ago, stole Planet Nine from its original star.

 

According to astronomers in Lund, there is a lot to indicate that Planet 9 was captured by the young sun and has been a part of our solar system completely undetected ever since.

 

Stars are born in clusters and often pass by one another. 

It is during these encounters that a star can 'steal' one or more planets in orbit around another star.  This is probably what happened when our own sun captured Planet 9.

 

The unknown world, dubbed 'Planet Nine' by some and 'Planet X' by others, is thought to be 10 times more massive than Earth and the furthest planet from the sun - but its exact location is unknown. 

 

The planet is predicted to circle the sun at a distance of about 40 billion to 140 billion miles (24 billion to 87 billion km), placing it far beyond all the other planets in our solar system.

Now physicists at the Harvard Smithsonian Centre for Astrophysics looked at the most likely scenarios for how a planet could get to such a distant part of the solar system. 

 

They found it is probably a gas giant that formed close to the sun and was kicked out by a series of gravitational pushes by nearby planets.

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100 remaining Mars One candidates to undergo 'intense' testing

100 remaining Mars One candidates to undergo 'intense' testing | Amazing Science | Scoop.it

Around 200,000 hopefuls from 140 countries initially signed up for the Mars One project, which is to be partly funded by a television reality show about the endeavour.

This has been whittled down to 100 people. 

 

After the five-day third phase of tests, it will be trimmed further to 40, of whom 24 will eventually be chosen for the one-way trips to the red planet, scheduled to start in 2026.

 

Mars One said the latest tests, 90 percent of which are those used by Nasa, will be done in teams. 'Over the course of five days, candidates will face various challenges,' the Dutch-based non-profit organisation said in a statement. 'It will be the first time all candidates will meet in person and demonstrate their capabilities as a team.

 

'In this round the candidates will play an active role in decision making/group formation. 'Mars One has asked the candidates to group themselves into teams with the people they believe they can work well with.' As they will not be returning to Earth, those selected must be capable of living in small groups, finding water, producing oxygen and growing their own food. 

 

Unlike Nasa's plans to go to Mars, these astronauts will only be offered a one-way ticket, and they'll need to survive by any means possible.

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Universe’s first life might have been born on diamond planets

Universe’s first life might have been born on diamond planets | Amazing Science | Scoop.it
New findings by scientists at the Harvard-Smithsonian Center for Astrophysics (CfA) suggest that planet formation in the early universe might have created carbon planets consisting of graphite, carbides, and diamond and that astronomers might find these diamond worlds by searching a rare class of stars.

“This work shows that even stars with a tiny fraction of the carbon in our solar system can host planets,” says lead author and Harvard University graduate student Natalie Mashian. “We have good reason to believe that alien life will be carbon-based, like life on Earth, so this also bodes well for the possibility of life in the early universe.”

The primordial universe consisted mostly of hydrogen and helium, and lacked chemical elements like carbon and oxygen necessary for life as we know it. Only after the first stars exploded as supernovae and seeded the second generation did planet formation and life become possible.

Clues to how life got started in the universe

Mashian and her PhD thesis advisor Avi Loeb examined a particular class of old stars known as carbon-enhanced metal-poor (CEMP) stars. These “anemic” stars contain only one hundred-thousandth as much iron as our Sun, meaning they formed before interstellar space had been widely seeded with heavy elements.

“These stars are fossils from the young universe,” explains Loeb. “By studying them, we can look at how planets, and possibly life in the universe, got started.”

CEMP stars have more carbon than would be expected, given their age. This relative abundance would influence planet formation as fluffy carbon dust grains (from supernovae) clump together to form tar-black worlds.

From a distance, these carbon planets would be difficult to tell apart from more Earth-like worlds. Their masses and physical sizes would be similar. Astronomers would have to examine their atmospheres for signs of their true nature. Gases like carbon monoxide and methane would envelop these unusual worlds.
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NASA’s Juno spacecraft prepares to probe Jupiter’s mysteries

NASA’s Juno spacecraft prepares to probe Jupiter’s mysteries | Amazing Science | Scoop.it
The mission will peek through the gas giant’s swirling clouds in search of a planetary core.

 

On 4 July, NASA intends to finish a job that started with the agency’s Galileo mission 21 years ago. At 8:18 p.m. Pacific time, the Juno spacecraft will ignite its main engine for 35 minutes and nudge itself into orbit around Jupiter. If all goes well, it will eventually slip into an even tighter path that whizzes as close as 4,200 kilometres above the planet’s roiling cloud-tops — while dodging as much of the lethal radiation in the planet’s belts as possible.

 

The US$1.1-billion mission, which launched in 2011, will be the first to visit the Solar System’s biggest planet since NASA’s Galileo spacecraft in 1995. Picking up where Galileo left off, Juno is designed to answer basic questions about Jupiter, including what its water content is, whether it has a core and what is happening at its rarely seen poles (see ‘Mission to Jupiter’).

 

Scientists think that Jupiter was the first planet to condense out of the gases that swirled around the newborn Sun 4.6 billion years ago. As such, it is made up of some of the most primordial material in the Solar System. Scientists know that it consists mostly of hydrogen and helium, but they are eager to pin down the exact amounts of other elements found on the planet.

 

“What we really want is the recipe,” says Scott Bolton, the mission’s principal investigator and a planetary scientist at the Southwest Research Institute in San Antonio, Texas.

 

Jupiter’s familiar visage, with its broad brown belts and striking Great Red Spot, represents only the tops of its churning clouds of ammonia and hydrogen sulfide. Juno — named after the Roman goddess who could see through clouds — will peer hundreds of kilometers into the planet’s atmosphere using microwave wavelengths.

 

Exploration of Jupiter’s interior should reveal more about the formidable atmospheric convection that powers the planet, says Paul Steffes, an electrical engineer at the Georgia Institute of Technology in Atlanta.  In anticipation of Juno’s arrival, professional and amateur astronomers have been observing Jupiter with ground-based and space-based telescopes. For now, the planet is not experiencing any unusual atmospheric changes. “It’s kind of in its normal state, which is good,” says Amy Simon, a planetary scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. This ‘normal’ behaviour gives researchers confidence that they will be able to understand Juno’s findings.

 

The Great Red Spot continues to shrink, as it has done in recent years, and to interact less and less with the jet streams on either of its edges. The broad belt just north of the planet’s equator has been expanding since late 2015 — a change that might be connected to processes deep in the atmosphere. “Trying to connect events that are happening at one level to events happening in another tells you how well coupled the whole atmosphere is,” says Leigh Fletcher, a planetary astronomer at the University of Leicester, UK.

 

As Juno probes deeper and deeper into the planet’s atmosphere, researchers hope to get information on a layer of hydrogen compressed into a liquid by increasing pressures. That liquid conducts electricity, which powers Jupiter’s enormous magnetic field. Deeper still, the spacecraft will look for evidence of a core — a dense nugget of heavier elements that most scientists think exists, but has never been observed. Juno will make precise measurements of how Jupiter’s gravity tugs on the spacecraft, which should reveal whether a core is present.

 

Juno will provide scientists with the last chance to look at Jupiter for a long time. It is scheduled to make 37 total orbits before performing a kamikaze run in early 2018, burning up inside the planet’s clouds to keep it from contaminating the moon Europa. The only other mission planned to the gas giant is the European Space Agency’s Jupiter Icy Moons Explorer (JUICE) spacecraft, which could launch as early as 2022 and will focus mainly on the moon Ganymede.

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When it comes to brown dwarfs, “how far away?” is a key question

When it comes to brown dwarfs, “how far away?” is a key question | Amazing Science | Scoop.it

Brown dwarfs are too small to sustain the hydrogen fusion process that powers stars. Their temperatures can range from nearly as hot as a star to as cool as a planet, and their masses also range between star-like and giant planet-like. They are of particular interest to scientists because they can offer clues to star-formation processes.

 

The intrinsic brightness of brown dwarfs, particularly cool brown dwarfs, is poorly known, but this key parameter can only be determined once an object’s distance has been measured.

 

Intrinsic brightness is a determination of how bright an object would be if observed at a common distance, eliminating the fact that a bright star can seem dimmer if it is far away and a dim star can seem brighter if it is close.

 

An ongoing planet-hunting survey run by Carnegie co-authors Alycia Weinberger, Alan Boss, Ian Thompson, Sandy Keiser, and others has yielded the distances to 134 low mass stars and brown dwarfs, of which 38 had not been previously measured. “Accurate distances are the foundation upon which we can determine the physical properties and luminosities of brown dwarfs and low mass stars,” Weinberger said.

 

The team built a special instrument for precisely measuring the locations of stars over time, the CAPSCam—the Carnegie Astrometric Planet Search Camera—and they use it at the DuPont Telescope at our Las Campanas Observatory in Chile.

 

The primary goal of the CAPS project is to search for extrasolar planets by the astrometric method, where the planet's presence can be detected indirectly through the wobble of the host star around the center of mass of the system. But CAPSCam also measures parallaxes to stars and brown dwarfs, including the 134 objects published in this study.

 

“There is still so much about brown dwarfs that remains unknown,” explained Weinberger. “As we learn more about them, it could improve our knowledge about the star formation process and possibly also refine our understanding of the distribution of matter in the universe, since it seems that there are far more brown dwarfs than initially thought.” The study revealed some other useful distance measurements in addition to the brown dwarf discoveries.

 

The team used the motion of two stars and compared them to others in two different stellar groups to confirm the age of the two stars age, between 30 and 50 million years old for one and 100 million years old for the other. This is because distance measurements can tell researchers about the location of a star in 3-D, not just the star’s position in 2-D on the sky, and let them measure the star’s velocity. Finding groups of young stars moving together lets astronomers study them in aggregate and better estimate how old they are and learn about their evolution.

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Saturn moon Enceladus’ ice shell likely thinner than expected

Saturn moon Enceladus’ ice shell likely thinner than expected | Amazing Science | Scoop.it
A vast ocean of water beneath the icy crust of Saturn’s moon Enceladus may be more accessible than previously thought, according to new research. A new study has revealed that near the moon’s poles, the ice covering Enceladus could be just two kilometers (one mile) thick—the thinnest known ice shell of any ocean-covered moon. The discovery not only changes scientists’ understanding of Enceladus’ structure, but also makes the moon a more appealing target for future exploration, according to the study’s authors.

 

Until recently, scientists saw Jupiter’s moon Europa as the moon most likely to yield new understanding into worlds with ice-covered oceans, according to Gabriel Tobie, a planetary scientist at the Laboratory of Planetology and Geodynamics of CNRS, the University of Nantes, and the University of Angers in Nantes, France and co-author of the new study.

 

Estimates of Europa’s ice shell thickness range from just a few kilometers to over 10 kilometers to over 20 kilometers (12 miles) thick. By comparison, Enceladus’ ice was previously thought to be 20 to 60 kilometers (12 to 37 miles) thick. But the new study suggests that at its south pole, Enceladus’ ice is less than five kilometers (three miles) thick, and possibly as little as two.

 

The thinness of the ice opens up future mission possibilities, according to authors of the new study published inGeophysical Research Letters, a journal of the American Geophysical Union. With ice this thin, an orbiting probe could use radar to see what lies beneath the moon’s shell. Though substantial engineering challenges would have to be solved first, scientists could even land a probe on the moon itself to drill down through the ice and sample the water below, Tobie said. Other scientists have proposed that ocean-covered moons like Europa could harbor life, and getting a look at Enceladus’ oceans could help us understand whether life could exist there, according to the authors.

 

The study yielded a second unexpected result: Enceladus’ core is likely much hotter than previously thought. Ice acts as an insulator, keeping the planet’s global oceans warm, but a thinner ice shell holds less heat. To maintain the same amount of water in the global oceans, with a thinner ice shell, Enceladus’ rocky core would have to generate much more heat than previously thought, according to the authors.

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K2-39b: A planet that shouldn't exist at all

K2-39b: A planet that shouldn't exist at all | Amazing Science | Scoop.it

An international team of astronomers has reported the discovery of a new giant extrasolar planet orbiting a subgiant star so closely that it should be destroyed due to tidal interactions. However, against all odds, the planet exists.

 

The planet, designated K2-39b, was first spotted by NASA's prolonged Kepler mission, known as K2. To confirm the planetary status of K2-39b, the team of researchers, led by Vincent Van Eylen of the Aarhus University in Denmark, has employed the High Accuracy Radial velocity Planet Searcher (HARPS) spectrograph on the ESO 3.6m telescope in La Silla, Chile, the Nordic Optical Telescope in La Palma, Canary Islands, as well as the Magellan II telescope at the Las Campanas Observatory in Chile.

 

The ground-based follow-up measurements were crucial to confirm that the newly found object was, indeed, a genuine exoplanet. The scientists conducted the so-called radial velocity measurements to measure the movement of the star caused by the planet. They clearly confirmed that the planet was indeed real, and also allowed the team to determine its mass.

 

According to the study, K2-39b is 50 times more massive than our planet and has a radius of about eight Earth radii. However, what is most intriguing about the new findings is that the planet is orbiting its evolved subgiant host star every 4.6 days, and so closely that it should be tidally destroyed.

 

"K2-39b is a bit of a 'special beast,' because such short-period planets orbiting large, evolved stars, are quite rare. (…) This planet is special mostly because of the star it orbits: Its host star is an evolved star, a subgiant several times larger than the sun. Around such stars, very few short-period planets were known, and there is speculation this may be because they cannot survive so close to such large stars. However, the fact that we have now found this planet, very close to a subgiant star, proves that at least some planets can survive there," Van Eylen explained.

 

Currently, there are two main theories attempting to explain the lack of close-in planets orbiting evolved subgiant stars. One of the hypotheses is that planets might be tidally destroyed as the star evolves and grows larger. The other scenario suggests that this is due to the systematically higher masses of the observed evolved stars compared to the observed main-sequence stars.

In the study, the scientists also attempt to estimate how long K2-39b can survive orbiting its sub-giant parent star. Taking into account the stellar mass of K2-39 and assuming that the planet remains in its current orbit, they suggest that the alien world will end its life probably in about 150 million years' time.

 

Furthermore, the team notes that it seems there may be a second planet in the system, at a much larger distance from the star. However, according to Van Eylen, the current data set has not been able to constrain this potential second planet. Further measurements may be able to do just that.

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Astronomers find the first 'wind nebula' around a magnetar

Astronomers find the first 'wind nebula' around a magnetar | Amazing Science | Scoop.it

Astronomers have discovered a vast cloud of high-energy particles called a wind nebula around a rare ultra-magnetic neutron star, or magnetar, for the first time. The find offers a unique window into the properties, environment and outburst history of magnetars, which are the strongest magnets in the universe.

 

A neutron star is the crushed core of a massive star that ran out of fuel, collapsed under its own weight, and exploded as a supernova. Each one compresses the equivalent mass of half a million Earths into a ball just 12 miles (20 kilometers) across, or about the length of New York’s Manhattan Island. Neutron stars are most commonly found as pulsars, which produce radio, visible light, X-rays and gamma rays at various locations in their surrounding magnetic fields. When a pulsar spins these regions in our direction, astronomers detect pulses of emission, hence the name.

 

Typical pulsar magnetic fields can be 100 billion to 10 trillion times stronger than Earth’s. Magnetar fields reach strengths a thousand times stronger still, and scientists don’t know the details of how they are created. Of about 2,600 neutron stars known, to date only 29 are classified as magnetars.

 

The newly found nebula surrounds a magnetar known as Swift J1834.9-0846—J1834.9 for short—which was discovered by NASA’s Swift satellite on Aug. 7, 2011, during a brief X-ray outburst. Astronomers suspect the object is associated with the W41 supernova remnant, located about 13,000 light-years away in the constellation Scutum toward the central part of our galaxy.

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Russian Crowdfunded Satellite May Soon Become Brightest "Star" in the Sky

Russian Crowdfunded Satellite May Soon Become Brightest "Star" in the Sky | Amazing Science | Scoop.it

We may soon look up and see a satellite brighter than the space station and even Venus gliding across the night sky if a Russian crowdfunding effort succeeds. An enthusiastic team of students from Moscow University of Mechanical Engineering are using Boomstarter, the Russian equivalent of Kickstarter, to raise the money needed to build and launch a pyramid-shaped satellite made of highly reflective material they’re calling Mayak, Russian for “Beacon”. To date they’ve collected more than $23,000 or 1.7 million rubles. Judging from the video, the team has built the canister that would hold the satellite (folded up inside) and performed a high-altitude test using a balloon. If funding is secured, Beacon is scheduled to launch on a Soyuz-2 rocket from the Baikonur Cosmodrome in the second quarter of this year.

 

Once in orbit, Beacon will inflate into a pyramid with a surface area of 172 square feet (16 square meters). Made of reflective metallized film 20 times thinner than a human hair, the satellite is expected to become the brightest man-made object in orbit ever. That title is currently held by the International Space Station which can shine as brightly as magnitude -3 or about three times fainter than Venus. The brightest satellites, the Iridiums, can flare to magnitude -8 (as bright as the crescent moon) but only for a few seconds before fading back to invisibility. They form a “constellation” of  some 66 satellites that provide data and voice communications.

 

A concurrently-developed mobile app would allow users to know when Beacon would pass over a particular location. The students hope to achieve more than just track a bright, moving light across the sky. According to their website, the goal of the project is the “popularization of astronautics and space research in Russia, as well as improving the attractiveness of science and technology education among young people.” They want to show that almost anyone can build and send a spacecraft into orbit, not just corporations and governments.

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NASA Just Confirmed That Earth Has A "Mini-Moon"

NASA Just Confirmed That Earth Has A "Mini-Moon" | Amazing Science | Scoop.it

NASA findings show that there is a tiny quasi-moon that's been orbiting the Earth for almost a century.

 

One is the loneliest number, especially if you’re a moon circling the Earth (Earth is rather far away, after all). But just as you are about to lose hope and accept your solitary fate, NASA announces there could be a second moon come to keep you company.

 

Sure, it is smaller than you and goes around the Earth amazingly irregularly, but still, two is always better than one. It turns out that the second “moon,” asteroid 2016 HO3, is currently locked into “a little dance” with Earth, and it has been dancing for a century. The rock’s orbit is highly elliptical, causing it to go a wee bit off tangent—between 38 and 100 times the distance of our planet’s primary moon—and bob up and down across Earth’s orbital plane.

 

HO3 is tilted by about 8° and it circles the Sun for 365.93 days, which is slightly longer than Earth’s 365.24 day-long year.


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First detection of methyl alcohol in a planet-forming disc

First detection of methyl alcohol in a planet-forming disc | Amazing Science | Scoop.it
The organic molecule methyl alcohol (methanol) has been found by the Atacama Large Millimeter/Submillimeter Array (ALMA) in the TW Hydrae protoplanetary disc. This is the first such detection of the compound in a young planet-forming disc. Its detection helps astronomers understand the chemical processes that occur during the formation of planetary systems and that ultimately lead to the creation of the ingredients for life.

The protoplanetary disc around the young star TW Hydrae is the closest known example to Earth, at a distance of only about 170 light-years. As such it is an ideal target for astronomers to study discs. This system closely resembles what astronomers think the Solar System looked like during its formation more than four billion years ago.

The Atacama Large Millimeter/Submillimeter Array (ALMA) is the most powerful observatory in existence for mapping the chemical composition and the distribution of cold gas in nearby discs. These unique capabilities have now been exploited by a group of astronomers led by Catherine Walsh (Leiden Observatory, the Netherlands) to investigate the chemistry of the TW Hydrae protoplanetary disc.

The ALMA observations have revealed the fingerprint of gaseous methyl alcohol, or methanol (CH3OH), in a protoplanetary disc for the first time. Methanol, a derivative of methane, is one of the largest complex organic molecules detected in discs to date. Identifying its presence in pre-planetary objects represents a milestone for understanding how organic molecules are incorporated into nascent planets.

Furthermore, methanol is itself a building block for more complex species of fundamental prebiotic importance, like amino acid compounds. As a result, methanol plays a vital role in the creation of the rich organic chemistry needed for life.

Catherine Walsh, lead author of the study, explains: "Finding methanol in a protoplanetary disc shows the unique capability of ALMA to probe the complex organic ice reservoir in discs and so, for the first time, allows us to look back in time to the origin of chemical complexity in a planet nursery around a young Sun-like star."

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UBC undergrad discovers four new 'planet candidates' thanks to class project

UBC undergrad discovers four new 'planet candidates' thanks to class project | Amazing Science | Scoop.it

Thanks to her work on a class project, a University of British Columbia science student has discovered four new planet candidates, including one, located 3,200 light years away from Earth, that could potentially support life-sustaining liquid water.
It was a needle in a haystack search for newly-graduated physics and astronomy student Michelle Kunimoto. She spent months of her final year at school poring over data collected from NASA's Kepler satellite as part of a class assignment aimed at giving students real-life exposure to a career in astronomy. Eventually she found four tiny specks that all the other scientists who examined the data had likely missed.

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'Wasteful' galaxies launch heavy elements into surrounding halos and deep space

'Wasteful' galaxies launch heavy elements into surrounding halos and deep space | Amazing Science | Scoop.it

Galaxies "waste" large amounts of heavy elements generated by star formation by ejecting them up to a million light years away into their surrounding halos and deep space, according to a new study led by the University of Colorado Boulder.

 

The research, which was recently published online in the Monthly Notices of the Royal Astronomical Society, shows that more oxygen, carbon and iron atoms exist in the sprawling, gaseous halos outside of galaxies than exist within the galaxies themselves, leaving the galaxies deprived of raw materials needed to build stars and planets.

 

"Previously, we thought that these heavier elements would be recycled in to future generations of stars and contribute to building planetary systems," said Benjamin Oppenheimer, a research associate in the Center for Astrophysics & Space Astronomy (CASA) at CU-Boulder and lead author of the study. "As it turns out, galaxies aren't very good at recycling."

 

The near-invisible reservoir of gas that surrounds a galaxy, known as the circumgalactic medium (CGM), is thought to play a central role in cycling elements in and out of the galaxy, but the exact mechanisms of this relationship remain elusive. A typical galaxy ranges in size from 30,000 to 100,000 light years while the CGM can span up to a million light years.

 

The researchers used data from the Cosmic Origin Spectrograph (COS), a $70 million instrument designed at CU-Boulder and built by Boulder, Colorado-based Ball Aerospace Technology Corp., to study the composition of the CGM.

 

COS is installed on NASA's Hubble Space Telescope and uses ultraviolet spectroscopy to study the evolution of the universe.

Spiral galaxies like the Milky Way actively form stars and have a blueish color while elliptical galaxies have little star formation and appear red. Both types of galaxies contain tens to hundreds of billions of stars that create heavy elements.

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Scientists break through the clouds to reveal source of Jupiter's wild weather

Scientists break through the clouds to reveal source of Jupiter's wild weather | Amazing Science | Scoop.it

The standard image of Jupiter is of a mysterious planet shrouded in colorful strips, spots and swirls. But what exactly is going on beneath the atmosphere's chaotic exterior is a question that has mystified astronomers for some time. Researchers have now peeled back the curtain by producing the most detailed radio map of Jupiter's atmosphere yet, revealing swathes of ammonia gas that drive its stormy weather and possibly, other giant planets just like it.

 

Confusion has previously plagued our understanding of Jupiter's atmosphere. In 1995, NASA's Galileo probe made the first detection of ammonia gas in another planet's atmosphere as it plummeted toward Jupiter, but doubt was cast on these observations when measurements taken by the Very Large Array (VLA) later revealed much lower concentrations. But upgrades to the VLA, along with a new method of interpreting its data, have now provided a way to account for previous inaccuracies.

 
"Jupiter's rotation once every 10 hours usually blurs radio maps, because these maps take many hours to observe," says study co-author Robert Sault, from the University of Melbourne. "But we have developed a technique to prevent this and so avoid confusing together the upwelling and downwelling ammonia flows, which had led to the earlier underestimate."
 
With the new and improved VLA, which has boosted its sensitivity by a factor of 10, an international team of scientists measured radio waves emitted from Jupiter that they know to be absorbed by ammonia. These were observed in wavelength bands where clouds are transparent, over the frequency range of four to eight GHz.
 
This allowed them to calculate the concentrations of ammonia at various locations around the planet's atmosphere, diving as deep as 100 km (62 mi) below the cloud tops to areas that had previously gone unexplored.
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Light pollution 'affects 80% of global population' - BBC News

Light pollution 'affects 80% of global population' - BBC News | Amazing Science | Scoop.it

More than 80% of the world's population lives under light-polluted skies, a study suggests.

 

Scientists explain in Science Advances how ground measurements and satellite data were used to create an atlas of a world brightened by artificial lights. It reveals that the population of Singapore, Kuwait and Qatar experience the brightest night skies. Conversely, people living in Chad, Central African Republic and Madagascar are least affected by light pollution.

 

Dr Christopher Kyba, from the German Research Centre for Geosciences in Potsdam, said: "The artificial light in our environment is coming from a lot of different things. "Street lights are a really important component, but we also have lights from our windows in our homes and businesses, from the headlights of our cars and illuminated billboards."

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