Earth as Hybrid Planet: New Classification Scheme Places Anthropocene Era in Astrobiological Context

Earth as Hybrid Planet: New Classification Scheme Places Anthropocene Era in Astrobiological Context:

For decades, as astronomers have imagined advanced extraterrestrial civilizations, they categorized such worlds by the amount of energy their inhabitants might conceivably be able to harness and use. They sorted the hypothetical worlds into three types according to a scheme named in 1964 for Soviet astronomer Nikolai Kardashev. A Type 1 civilization could manipulate all the energy resources of its home planet (a distant goal yet for Earth) and Type 2 all the energy in its star/planetary system. A super-advanced Type 3 civilization would command the energy of its whole home galaxy. The Kardashev Scale has since become a sort of gold standard for dreaming about possible civilizations beyond Earth.

Now, a team of researchers including Marina Alberti of the University of Washington has devised a new classification scheme for the evolutionary stages of worlds based on “non-equilibrium thermodynamics” — a planet’s energy flow being out of synch, as the presence of life could cause. The categories range from imagined planets with no atmosphere whatsoever to those with an “agency-dominated biosphere” or even a “technosphere,” reflecting the achievements of a vastly advanced, “energy-intensive technological species.”

Their paper, “Earth as a Hybrid Planet: The Anthropocene in an Evolutionary Astrobiological Context,” was published Sept. 6 in the journal Anthropocene. Lead author is Adam Frank, professor of physics and astronomy at the University of Rochester. Alberti is a professor of urban design and planning in the UW College of Built Environments, and director of the college’s Urban Ecology Research Lab.

The new classification system, the researchers say, is a way of thinking about sustainability on a planetary scale in what is being recognized as the Anthropocene epoch — the geological period of humanity’s significant impact on Earth and its ecosystems. Alberti contends in her research that humans and the urban areas we create are having a strong, planetwide effect on evolution.

“Our premise is that Earth’s entry into the Anthropocene represents what might, from an astrobiological perspective, be a predictable planetary transition,” they write. “We explore this problem from the perspective of our own solar system and exoplanet studies.

“In our perspective, the beginning of the Anthropocene can be seen as the onset of the hybridization of the planet — a transitional stage from one class of planetary systems to another.”

That would be, in their scheme, Earth’s possible transition from Class IV — marked by a thick biosphere and life having some effect on the planet — to the final Class V, where a planet is profoundly affected by the activity of an advanced, energy-intensive species.

The classification scheme, the researchers write, is based on “the magnitude by which different planetary processes — abiotic, biotic and technologic — generate free energy, i.e. energy that can perform work within the system.”

• Class I represents worlds with no atmosphere at all, such as the planet Mercury and the Earth’s moon.
• Class II planets have a thin atmosphere containing greenhouse gases, but no current life, such as the current states of planets Mars and Venus.
• Class III planets have perhaps a thin biosphere and some biotic activity, but much too little to “affect planetary drivers and alter the evolutionary state of the planet as a whole.” No current examples exist in the solar system, but early Earth may have represented such a world — and possibly early Mars, if life ever flickered there in the distant past.
• Class IV planets have a thick biosphere sustained by photosynthetic activity and life has begun strongly affecting the planetary energy flow.

Alberti said, “The discovery of seven new exoplanets orbiting the relatively close star TRAPPIST-1 forces us to rethink life on Earth. It opens the possibility to broaden our understanding of coupled system dynamics and lay the foundations to explore a path to long-term sustainability by entering into a cooperative ecological-evolutionary dynamic with the coupled planetary systems.”

The researchers write, “Our thesis is that the development of long-term sustainable, versions of an energy-intensive civilization must be seen on a continuum of interactions between life and its host planet.”

The classifications lay the groundwork, they say, for future research on the “co-evolution” of planets along that continuum.

“Any world hosting a long-lived energy-intensive civilization must share at least some similarities in terms of the thermodynamic properties of the planetary system,” they write. “Understanding these properties, even in the broadest outlines, can help us understand which direction we must aim our efforts in developing a sustainable human civilization.”

In other words, they added, “If one does not know where one is going, it’s hard to get there.”

Co-author on the paper is Axel Kleidon of the Max Planck Institute for Biogeochemistry in Jena, Germany.

Credit: washington.edu

Accretion-Powered Pulsar Reveals Unique Timing Glitch

Accretion-Powered Pulsar Reveals Unique Timing Glitch:

The discovery of the largest timing irregularity yet observed in a pulsar is the first confirmation that pulsars in binary systems exhibit the strange phenomenon known as a ‘glitch’. The study is published in the journal Monthly Notices of the Royal Astronomical Society.

Pulsars are one possible result of the final stages of evolution of massive stars. Such stars end their lives in huge supernova explosions, ejecting their stellar materials outwards into space and leaving behind an extremely dense and compact object; this could either be a white dwarf, a neutron star or a black hole.

If a neutron star is left, it may have a very strong magnetic field and rotate extremely quickly, emitting a beam of light that can be observed when the beam points towards Earth, in much the same way as a lighthouse beam sweeping past an observer. To the observer on Earth, it looks as though the star is emitting pulses of light, hence the name ‘pulsar’.

Now a group of scientists from the Middle East Technical University and Başkent University in Turkey have discovered a sudden change in the rotation speed of the peculiar pulsar SXP 1062. These jumps in frequency, known as ‘glitches’, are commonly seen in isolated pulsars, but have so far never been observed in binary pulsars (pulsars orbiting with a companion white dwarf or neutron star) such as SXP 1062.

SXP 1062 is located in the Small Magellanic Cloud, a satellite galaxy of our own Milky Way galaxy, and one of our nearest intergalactic neighbors at 200,000 light years away. Lead author of the study, Mr M. Miraç Serim, a senior PhD student working under the supervision of Prof Altan Baykal, said, “This pulsar is particularly interesting, since as well as orbiting its partner star as part of a binary pair, it is also still surrounded by the remnants of the supernova explosion which created it.”

The pulsar is thought to pull in the leftover material from the supernova explosion, feeding on it in a process known as accretion. The team believe that the size of the glitch is due to the gravitational influence of its companion star and this accretion of the surrounding remnant material, which together exert large forces on the crust of the neutron star. When these forces are no longer sustainable, a rapid change in internal structure transfers momentum to the crust, changing the rotation of the pulsar very suddenly and producing a glitch.

“The fractional frequency jump observed during this glitch is the largest, and is unique to this particular pulsar”, commented Dr Şeyda Şahiner, a co-author of the study. “The size of the glitch indicates that the interiors of neutron stars in binary systems may be quite different to the interiors of isolated neutron stars.”

This work was initially presented in 2017 at the European Week of Astronomy and Space Science, which will be held next year in Liverpool jointly with the UK National Astronomy Meeting. The work will be followed up with NASA’s Neutron Star Interior Composition Explorer (NICER) mission, launched in June this year – the team hope that the finding may lead to a better understanding of the interior of the neutron stars, putting new constraints on the neutron star equation of state.

Credit: ras.org.uk

Exchanges of Identity in Deep Space

Exchanges of Identity in Deep Space:

Like in a nail-biting thriller full of escapes and subterfuge, photons from far-off light sources, such as blazars, could go up against a continuous exchange of identity in their journey through the Universe. This is an operation that would allow these very tiny particles of light to escape an enemy which, if encountered, would annihilate them.

This is the phenomenon studied by a group of researchers from the University of Salento, Bari, the National Institute for Nuclear Physics (INFN), the National Institute for Astrophysics (INAF) and SISSA thanks to brand new simulation models that reproduce the complexity of the cosmos as never before. Normally, very high energy photons (gamma rays) should "collide" with the background light emitted by galaxies transformed into pairs of matter and antimatter particles, as envisaged by the Theory of Relativity. For this reason, the sources of very high energy gamma rays should appear significantly less bright than what is observed in many cases.

A possible explanation for this surprising anomaly is that light photons are transformed into hypothetical weakly-interacting particles, "axions" which, in turn, would change into photons, all due to the interaction with magnetic fields. With these metamorphoses, a part of the photons would escape interaction with the intergalactic background light that would make them disappear. The importance of this process is emphasized by the study published on Physical Review Letters, which re-created an extremely refined model of the Cosmic Web, a network of filaments composed of gas and dark matter present throughout the Universe and of its magnetic fields. The aforementioned effects are now awaiting comparison with those obtained experimentally through Cherenkov Telescope Array new generation telescopes.

In this research, through complex and unprecedented computer simulations made at the CSCS Supercomputing Centre in Lugano, scholars have reproduced the so-called Cosmic Web and the magnetic fields associated with this to investigate the possibility, advanced from previous theories, that photons from a light source are transformed into axions, hypothetical elementary particles, on interacting with an extragalactic magnetic field. Axions could then be retransformed into photons by interacting with other magnetic fields. 

Researchers Daniele Montanino, Franco Vazza, Alessandro Mirizzi and Matteo Viel explain: "Photons from luminous bodies disappear when they encounter extragalactic background light (EBL). But if on their journey they head into these transformations as envisaged by these theories, it would explain why, in addition to giving very important information on processes that occur in the universe, distant celestial bodies are brighter than expected from an observation on Earth. These changes would, in fact, enable a greater number of photons to reach the Earth".

In the simulations made by scientists, thanks to the wealth of magnetic fields present in the Cosmic Web's filaments recreated with the simulations, the conversion phenomenon would seem much more relevant than predicted by previous models: "Our simulations reproduce a very realistic picture of the cosmos' structure. From what we have observed, the distribution of the Cosmic Web envisaged by us would markedly increase the probability of these transformations".

The next step in the research? To compare simulation results with the experimental data obtained through the use of the Cherenkov Telescope Array Observatories detectors, the new-generation astronomical observatories, one of which is positioned in the Canary Islands and the other in Chile, that will study the Universe through very high energy gamma rays.

Credit: sissa.it

Ultraviolet Light from Superluminous Supernova Key to Revealing Explosion Mechanism

Ultraviolet Light from Superluminous Supernova Key to Revealing Explosion Mechanism:

An international team of researchers has discovered a way to use observations at ultraviolet (UV) wavelengths to uncover characteristics about superluminous supernovae previously impossible to determine, reports a new study published in Astrophysical Journal Letters on August 3, 2017.

The team, led by Kavli Institute for the Physics and Mathematics of the Universe (Kavli IPMU) Project Researcher Alexey Tolstov, studies stellar explosions called Superluminous Supernovae (SLSNe), an extra bright type of supernova discovered in the last decade that is 10 to 100 times brighter than ordinary supernovae. Recently, the team came upon Gaia16apd in a faint dwarf galaxy 1.6 billion light years away.

This SLSNe had an extraordinary UV-bright emission for a supernova of its kind, but no one could explain what explosion mechanism could produce that feature. Theorists have debated that Gaia16apd could fit one of three SLSNe scenarios. These are the pair-instability supernova, having a large mass of radioactive Nickel-56, or a magnetar-powered supernova where there would be a rapidly spinning and highly magnetized neutron star as an additional energy source, or a shock-interacting supernova where the supernova ejecta would interact with the surrounding dense circumstellar matter.

Researchers from Kavli IPMU therefore decided to simulate each model using multicolor radiation hydrodynamics to study light in different colors and ranges of wavelengths and see whether any of the simulations matched with the observed supernova. These simulations produced ultraviolet, visible-light and infrared light curves, photospheric radius and velocity, making it possible to investigate the appearance of the explosion at any wavelength.

Not only did they discover that Gaia16apd was most likely a shock-interacting supernova, Tolstov and his team found a way to model three different scenarios at UV wavelengths using the same numerical technique. In the future, their technique could help researchers in identifying the explosion mechanism of supernova they observe.

“The current study makes one more step to the understanding of the physics of superluminous supernova and helps to identify the scenario of the explosion. The observations and more detailed modeling of the peculiar objects similar to Gaia16apd are highly in demand to find out the nature of the phenomenon of superluminous supernovae,” said Tolstov.

The next step in their research will be to apply simulations on other SLSNe, and make more realistic models by considering the asymmetry of the explosion and physics of the magnetar-powered supernova.

Credit: ipmu.jp

Scientists Produce Unique Simulation of Magnetic Reconnection

Scientists Produce Unique Simulation of Magnetic Reconnection:

Jonathan Ng, a Princeton University graduate student at the U.S. Department of Energy’s (DOE) Princeton Plasma Physics Laboratory (PPPL), has for the first time applied a fluid simulation to the space plasma process behind solar flares northern lights and space storms. The model could lead to improved forecasts of space weather that can shut down cell phone service and damage power grids, as well as to better understanding of the hot, charged plasma gas that fuels fusion reactions.

The new simulation captures the physics of magnetic reconnection, the breaking apart and snapping together of the magnetic field lines in plasma that occurs throughout the universe. The simulations approximate kinetic effects in a fluid code, which treats plasma as a flowing liquid, to create a more detailed picture of the reconnection process. 

Previous simulations used fluid codes to produce simplified descriptions of reconnection that takes place in the vastness of space, where widely separated plasma particles rarely collide. However, this collisionless environment gives rise to kinetic effects on plasma behavior that fluid models cannot normally capture.

The new simulation estimates kinetic behavior. “This is the first application of this particular fluid model in studying reconnection physics in space plasmas,” said Ng, lead author of the findings reported in August in the journal Physics of Plasmas.

Ng and coauthors approximated kinetic effects with a series of fluid equations based on plasma density, momentum and pressure. They concluded the process through a mathematical technique called “closure” that enabled them to describe the kinetic mixing of particles from non-local, or large-scale, regions. The type of closure involved was originally developed by PPPL physicist Greg Hammett and the late Rip Perkins in the context of fusion plasmas, making its application to the space plasma environment an example of fruitful cross-fertilization.

The completed results agreed better with kinetic models as compared with simulations produced by traditional fluid codes. The new simulations could extend understanding of reconnection to whole regions of space such as the magnetosphere, the magnetic field that surrounds the Earth, and provide a more comprehensive view of the universal process.

Coauthoring the paper were physicists Ammar Hakim of PPPL and Amitava Bhattacharjee, head of the Theory Department at PPPL and a professor of astrophysical sciences at Princeton University, together with physicists Adam Stanier and William Daughton of Los Alamos National Laboratory. Support for this work comes from the DOE Office of Science, the National Science Foundation and NASA. Computation was performed at the National Energy Research Scientific Computer Center, a DOE Office of Science User Facility, and the University of New Hampshire.

Credit: pppl.gov

Are We Being Watched? Tens of Other Worlds Could Spot the Earth

Are We Being Watched? Tens of Other Worlds Could Spot the Earth:

A group of scientists from Queen’s University Belfast and the Max Planck Institute for Solar System Research in Germany have looked at how an alien observer might be able to detect Earth using our own methods. They find that at least nine exoplanets are ideally placed to observe transits of Earth, in a new work published in the journal Monthly Notices of the Royal Astronomical Society.

Thanks to facilities and missions such as SuperWASP and Kepler, we have now discovered thousands of planets orbiting stars other than our Sun, worlds known as ‘exoplanets’. The vast majority of these are found when the planets cross in front of their host stars in what are known as ‘transits’, which allow astronomers to see light from the host star dim slightly at regular intervals every time the planet passes between us and the distant star.

In the new study, the authors reverse this concept and ask, “How would an alien observer see the Solar System?” They identified parts of the distant sky from where various planets in our Solar System could be seen to pass in front of the Sun – so-called ‘transit zones’ -- concluding that the terrestrial planets (Mercury, Venus, Earth, and Mars) are actually much more likely to be spotted than the more distant ‘Jovian’ planets (Jupiter, Saturn, Uranus, and Neptune), despite their much larger size.

”Larger planets would naturally block out more light as they pass in front of their star”, commented lead author Robert Wells, a PhD student at Queen’s University Belfast. ”However the more important factor is actually how close the planet is to its parent star – since the terrestrial planets are much closer to the Sun than the gas giants, they’ll be more likely to be seen in transit.”

To look for worlds where civilizations would have the best chance of spotting our Solar System, the astronomers looked for parts of the sky from which more than one planet could be seen crossing the face of the Sun. They found that three planets at most could be observed from anywhere outside of the Solar System, and that not all combinations of three planets are possible.

Katja Poppenhaeger, a co-author of the study, added: “We estimate that a randomly positioned observer would have roughly a 1 in 40 chance of observing at least one planet. The probability of detecting at least two planets would be about ten times lower, and to detect three would be a further ten times smaller than this.”

Of the thousands of known exoplanets, the team identified sixty-eight worlds where observers would see one or more of the planets in our Solar System transit the Sun. Nine of these planets are ideally placed to observe transits of Earth, although none of the worlds are deemed to be habitable.

In addition, the team estimate that there should be approximately ten (currently undiscovered) worlds which are favorably located to detect the Earth and are capable of sustaining life as we know it. To date however, no habitable planets have been discovered from which a civilization could detect the Earth with our current level of technology.

The ongoing K2 mission of NASA’s Kepler spacecraft is to continue to hunt for exoplanets in different regions of the sky for a few months at a time. These regions are centered close to the plane of Earth’s orbit, which means that there are many target stars located in the transit zones of the Solar System planets. The team’s plans for future work include targeting these transit zones to search for exoplanets, hopefully finding some which could be habitable.

Credit: qub.ac.uk

Large Asteroid to Fly by Earth Today

Large Asteroid to Fly by Earth Today:

Large near-Earth object (NEO), designated 2017 OP68, will fly by our planet today, missing the Earth at a distance of about 19.9 lunar distances (LD), or 7.6 million kilometers. The close approach is expected to occur at 18:25 UTC, when the space rock will whiz by our planet with a velocity of 11.7 km/s.

2017 OP68 is an Amor-type asteroid first spotted on July 25, 2017 by NASA’s Wide-field Infrared Survey Explorer (WISE). WISE is infrared-wavelength astronomical space telescope that has discovered thousands of minor planets.

Astronomers reveal that 2017 OP68 has an absolute magnitude of 20.6 and a diameter between 150 and 470 meters. The asteroid has an orbital period of nearly four years and a semimajor axis of about 2.5 AU.

Next close approach of 2017 OP68 to Earth is expected to take place on July 17, 2021, when it will pass by our planet at a much larger distance of 131 LD (50.3 million kilometers).

On September 10, 2017, there were 1,803 potentially hazardous asteroids (PHAs) discovered to date. PHAs are space rocks larger than approximately 100 meters that can come closer to Earth than 19.5 LD. However, none of the known PHAs is on a collision course with our planet.

Explosive Birth of Stars Swells Galactic Cores

Explosive Birth of Stars Swells Galactic Cores:

Astronomers found that active star formation upswells galaxies, like yeast helps bread rise. Using three powerful telescopes on the ground and in orbit, they observed galaxies from 11 billion years ago and found explosive formation of stars in the cores of galaxies. This suggests that galaxies can change their own shape without interaction with other galaxies.

"Massive elliptical galaxies are believed to be formed from collisions of disk galaxies," said Ken-ichi Tadaki, the lead author of two research papers and a postdoctoral researcher at the National Astronomical Observatory of Japan (NAOJ). "But, it is uncertain whether all the elliptical galaxies have experienced galaxy collision. There may be an alternative path."

Aiming to understand galactic metamorphosis, the international team explored distant galaxies 11 billion light-years away. Because it takes time for the light from distant objects to reach us, by observing galaxies 11 billion light-years away, the team can see what the Universe looked like 11 billion years ago, 3 billion years after the Big Bang. This corresponds the peak epoch of galaxy formation; the foundations of most galaxies were formed in this epoch.

Receiving faint light which has traveled 11 billion years is tough work. The team harnessed the power of three telescopes to anatomize the ancient galaxies. First, they used NAOJ's 8.2-m Subaru Telescope in Hawai`i and picked out 25 galaxies in this epoch. Then they targeted the galaxies for observations with NASA/ESA's Hubble Space Telescope (HST) and the Atacama Large Millimeter/submillimeter Array (ALMA). The astronomers used HST to capture the light from stars which tells us the "current" (as of when the light was emitted, 11 billion years ago) shape of the galaxies, while ALMA observed submillimeter waves from cold clouds of gas and dust, where new stars are being formed. By combining the two, we know the shapes of the galaxies 11 billion years ago and how they are evolving.

Thanks to their high resolution, HST and ALMA could illustrate the metamorphosis of the galaxies. With HST images the team found that a disk component dominates the galaxies. Meanwhile, the ALMA images show that there is a massive reservoir of gas and dust, the material of stars, so that stars are forming very actively. The star formation activity is so high that huge numbers of stars will be formed at the centers of the galaxies. This leads the astronomers to think that ultimately the galaxies will be dominated by the stellar bulge and become elliptical or lenticular galaxies.

"Here, we obtained firm evidence that dense galactic cores can be formed without galaxy collisions. They can also be formed by intense star formation in the heart of the galaxy." said Tadaki. The team used the European Southern Observatory's Very Large Telescope to observe the target galaxies and confirmed that there are no indications of massive galaxy collisions.

Almost 100 years ago, American astronomer Edwin Hubble invented the morphological classification scheme for galaxies. Since then, many astronomers have devoted considerable effort to understanding the origin of the variety in galaxy shapes. Utilizing the most advanced telescopes, modern astronomers have come one step closer to solving the mysteries of galaxies.

Credit: alma-telescope.jp

Galaxies Swell due to Explosive Action of New Stars

Galaxies Swell due to Explosive Action of New Stars:

In 1926, famed astronomer Edwin Hubble developed his morphological classification scheme for galaxies. This method divided galaxies into three basic groups – Elliptical, Spiral and Lenticular – based on their shapes. Since then, astronomers have devoted considerable time and effort in an attempt to determine how galaxies have evolved over the course of billions of years to become these shapes.

One of th most widely-accepted theories is that galaxies changed by merging, where smaller clouds of stars – bound by mutual gravity – came together, altering the size and shape of a galaxy over time. However, a new study by an international team of researchers has revealed that galaxies could actually assumed their modern shapes through the formation of new stars within their centers.

The study, titled “Rotating Starburst Cores in Massive Galaxies at z = 2.5“, was recently published in the Astrophysical Journal Letters. Led by Ken-ichi Tadaki – a postdoctoral researcher with the Max Planck Institute for Extraterrestrial Physics and the National Astronomical Observatory of Japan (NAOJ) – the team conducted observations of distant galaxies in order to get a better understanding of galactic metamorphosis.

Evolution diagram of a galaxy. First the galaxy is dominated by the disk component (left) but active star formation occurs in the huge dust and gas cloud at the center of the galaxy (center). Then the galaxy is dominated by the stellar bulge and becomes an elliptical (or lenticular) galaxy. Credit: NAOJ

This involved using ground-based telescopes to study 25 galaxies that were at a distance of about 11 billion light-years from Earth. At this distance, the team was seeing what these galaxies looked like 11 billion years ago, or roughly 3 billion years after the Big Bang. This early epoch coincides with a period of peak galaxy formation in the Universe, when the foundations of most galaxies were being formed. As Dr. Tadaki indicated in a NAOJ press release:

“Massive elliptical galaxies are believed to be formed from collisions of disk galaxies. But, it is uncertain whether all the elliptical galaxies have experienced galaxy collision. There may be an alternative path.”

Capturing the faint light of these distant galaxies was no easy task and the team needed three ground-based telescopes to resolve them properly. They began by using the NAOJ’s 8.2-m Subaru Telescope in Hawaii to pick out the 25 galaxies in this epoch. Then they targeted them for observations with the NASA/ESA Hubble Space Telescope (HST) and the Atacama Large Millimeter/submillimeter Array (ALMA) in Chile.

Whereas the HST captured light from stars to discern the shape of the galaxies (as they existed 11 billion years ago), the ALMA array observed submillimeter waves  emitted by the cold clouds of dust and gas – where new stars are being formed. By combining the two, they were able to complete a detailed picture of how these galaxies looked 11 billion years ago when their shapes were still evolving.

Observation images of a galaxy 11 billion light-years away. Credit: ALMA (ESO/NAOJ/NRAO), NASA/ESA Hubble Space Telescope, Tadaki et al.

What they found was rather telling. The HST images indicated that early galaxies were dominated by a disk component, as opposed to the central bulge feature we’ve come to associate with spiral and lenticular galaxies. Meanwhile, the ALMA images showed that there were massive reservoirs of gas and dust near the centers of these galaxies, which coincided with a very high rate of star formation.

To rule out alternate possibility that this intense star formation was being caused by mergers, the team also used data from the European Southern Observatory’s Very Large Telescope (VLT) – located at the Paranal Observatory in Chile – to confirm that there were no indications of massive galaxy collisions taking place at the time. As Dr. Tadaki explained:

“Here, we obtained firm evidence that dense galactic cores can be formed without galaxy collisions. They can also be formed by intense star formation in the heart of the galaxy.”

These findings could lead astronomers to rethink their current theories about galactic evolution and howthey came to adopt features like a central bulge and spiral arms. It could also lead to a rethink of our models regarding cosmic evolution, not to mention the history of own galaxy. Who knows? It might even cause astronomers to rethink what might happen in a few billion years, when the Milky Way is set to collide with the Andromeda Galaxy.

As always, the further we probe into the Universe, the more it reveals. With every revelation that does not fit our expectations, our hypotheses are forced to undergo revision.

Further Reading: ALMA, Astrophysical Journal Letters

The post Galaxies Swell due to Explosive Action of New Stars appeared first on Universe Today.

Astronomers create best ever image of star outside our Solar System

Astronomers create best ever image of star outside our Solar System:

Using ESO’s Very Large Telescope Interferometer astronomers have constructed this image of the red supergiant star Antares. This is the most detailed image ever of this object, or any other star apart from the Sun. Image & Caption Credit: K. Ohnaka / ESO

A map of activity on the surface and in the atmosphere of the star Antares by a team of astronomers is considered to be the most detailed ever created for a star other than the Sun. The red supergiant is located some 550 light-years distant in the constellation Scorpius and is in its final stages of its existence. It will eventually die in a supernova explosion.

While Antares likely started its life with about 15 times the mass of our Sun, it is now shedding mass and is estimated to have lost about three solar masses. Its current diameter is approximately 700 times that of the Sun.

Researchers led by Keiichi Ohnaka of the Universidad Catolico del Norte in Chile used the European Southern Observatory’s (ESO) Very Large Telescope Interferometer (VLTI) at Paranal Observatory to map the surface of the luminous, low-density star and measure the speed at which surface material is moving.

The VLTI is an instrument composed of several telescopes that create the equivalent of a single large telescope with a mirror boasting a diameter up to 656 feet (200 meters). It combines the light from as many as four telescopes, including either the 26.9-foot (8.2-meter) Unit Telescopes or the 5.9-foot (1.8-meter) Auxiliary Telescopes, enabling scientists to view the star in incredible detail.

This artist’s impression shows the red supergiant star Antares in the constellation of Scorpius. Image & Caption Credit: M. Kornmesser / ESO

Using three Auxiliary Telescopes along with the near-infrared AMBER instrument, astronomers imaged several locales on Antares’ surface in various infrared wavelengths to measure the speed at which gases are moving in these different regions and across the entire star. The technique yielded the most detailed map of surface activity by atmospheric gases on any star besides our Sun.

Ohnaka said a central goal of the study is to determine how stars like Antares lose so much mass at the end of their lives.

“The VLTI is the only facility that can directly measure the gas motions in the extended atmosphere of Antares – a crucial step towards clarifying this problem. The next challenge is to identify what’s driving the turbulent motions,” Ohnaka said.

This is the first such velocity map of any star other than the Sun. In red regions, the material is moving away from Earth, and in the blue areas, the material is approaching. The empty region around the star is not a real feature but shows where velocity measurements were not possible. Image & Caption Credit: K. Ohnaka / ESO

Low-density gas was discovered extending much further from the star than the researchers expected, leading them to conclude it was brought there by a process other than convection, which involves the transfer of energy from a star’s core to its outer atmosphere. Just what that process is remains unknown.

Other stars of various types will need to be studied using the technique astronomers used to map Antares in the same degree of detail for scientists to determine what that process is, Ohnaka said.

“Our work brings stellar astrophysics to a new dimension and opens an entirely new window to observe stars,” Ohnaka said.

Ohnaka is the lead author of a paper on the study published in the journal Nature.

This chart shows the constellation of Scorpius. At the heart of this grouping of stars lies the bright red supergiant star Antares. Image & Caption Credit: ESO / IAU / Sky & Telescope

This article was updated at 16:55 EDT on Aug. 27, 2017, with distance to Antares.



The post Astronomers create best ever image of star outside our Solar System appeared first on SpaceFlight Insider.

JPL proposes exploring Venus with a clockwork rover

JPL proposes exploring Venus with a clockwork rover:

AREE is a clockwork rover inspired by mechanical computers. A JPL team is studying how this kind of rover could explore extreme environments, like the surface of Venus. Image & Caption Credit: NASA/JPL-Caltech

NASA’s Jet Propulsion Laboratory (JPL) proposes taking a page out of a Swiss watchmaker’s handbook to design a long-lived rover to explore Venus’ surface. Utilizing centuries-old mechanical computing concepts, but with a modern upgrade, engineers at JPL hope to design a rover capable of exploring the unforgiving Venusian terrain and returning data to Earth.

Today’s forecast: Cloudy with a high of 864 °F

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The surface of Venus is perpetually shrouded from view by heavy cloud cover. Photo Credit: NASA

Though Venus has been called Earth’s sister due to the similarities in size and mass between the two, humanity knows comparatively little about the planet itself. Indeed, the Soviet Venera and Vega programs of the 1970s and 1980s have provided the only surface-based investigations of Earth’s nearest planetary neighbor.

While the landers returned valuable data, they operated for no more than a couple hours before succumbing to the intense heat and pressure of Venus’ atmosphere. With an average surface temperature of 864 degrees Fahrenheit (462 degrees Celsius) – hot enough to melt lead – and an atmospheric pressure more than 90 times that of Earth’s, even modern hardware would have difficulty operating for very long.

With the hellish surface conditions being a major hurdle to overcome, scientists have had to be content with observations from above the cloud tops.

Tick-tock goes the… rover?

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Although technology has made great strides since the Soviet landers, heat is just as deadly to modern electronics as it was in the 1980s. Faced with the difficulty of designing hardware to operate on Venus’ surface, conventional wisdom seemed to dictate one of two paths: developing a cooling system that would work in such extreme conditions, or designing high-temperature electronics.

With a cooling system costing billions of dollars to develop, and heat-tolerant hardware exceeding the design tolerances of a rover, neither seemed a viable path for some designers.

Enter Jonathan Sauder, a mechatronics engineer at JPL and the inspiration behind the Automaton Rover for Extreme Environments (AREE) program. Sauder believes mechanical computing is the key to designing a long-lasting Venusian rover.

“Venus is too inhospitable for kind of complex control systems you have on a Mars rover,” Sauder stated in a release issued by JPL. “But with a fully mechanical rover, you might be able to survive as long as a year.”

Mechanically driven devices have been around for centuries. Some, like the Antikythera mechanism, were used to compute astronomical events. Others were designed as works of art. Though seemingly less-advanced than electronic devices, mechanical computers have the advantage of being able to operate under conditions that would cripple their modern counterparts.

“When you think of something as extreme as Venus, you want to think really out there,” stated Evan Hilgemann, a JPL engineer working on high-temperature designs for AREE, in the same release.

RIGHT IMAGE: A look inside the AREE rover (next to an astronaut for scale). Wind would be channeled through the rover’s body for primary power. Rotating targets on top could be “pinged” by radar, sending data as Morse code. (Click to enlarge) Images & Caption Credit: NASA / JPL-Caltech

Not only would the rover operate under mechanical guidance, but its communication system would be similarly basic.

Utilizing a mechanism that would re-orient radar-reflective panels, the rover could communicate with an orbiting spacecraft. Far overhead, the spacecraft would beam down a radar signal that would bounce off the rover’s reflective panels. These panels could be oriented in a fashion to allow for simple communication between the two explorers, thus enabling the relaying of data back to Earth.

The program is now in its second phase of development, with engineers determining which components of the concept should be refined and further advanced.

Automaton Rover for Extreme Environments (AREE)
Video courtesy of Jonathan Sauder / JPL / NASA

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Johnson Space Center closed through Labor Day to evaluate safety after Harvey

Johnson Space Center closed through Labor Day to evaluate safety after Harvey:

Tropical Storm Harvey as seen by the crew of the International Space Station on Aug. 29, 2017. Photo Credit: Randy Bresnik / NASA

Hurricane Harvey, now a tropical storm, has prompted NASA to cancel an in-flight question and answer session with Expedition 52 astronaut Peggy Whitson, who is currently aboard the International Space Station. Additionally, the Johnson Space Center will remain closed until Sept. 5, 2017, to all but mission mission-essential personnel while officials evaluate the safety of the center.

A 30-minute news conference with Whitson, who has been residing at the outpost since November 2016 and will return to Earth this weekend, was planned for Aug. 30. However, because of the Johnson Space Center’s closure, mission-essential staff will not be able to support the in-flight event.

Moreover, live satellite interviews with NASA astronauts Mark Vande Hei and Joe Acaba, who are in Russia, have also been canceled. The U.S. space agency originally cited a change in the crew’s training schedule for the cancellation, but because the event was planned for Sept. 1, there will also be no staff to support the event.

Vande Hei and Acaba will launch to the space station with cosmonaut Alexander Misurkin on Sept. 12 inside their Soyuz MS-06 spacecraft. Liftoff is scheduled for 5:17 p.m. EDT (21:17 GMT). They will remain at the outpost until February 2018.

Harvey made its first landfall near Corpus Christi, Texas, on Aug. 26 with maximum sustained winds of 130 mph (210 km/h): a Category 4 hurricane. The 280-mile (450-kilometer) wide storm soon stalled over the state before moving back out into the Gulf of Mexico. It made a second landfall on Aug. 30 near the Texas-Louisiana border, this time as a tropical storm with sustained winds of 45 mph (73 km/h).

So far, the storm has dropped more than 50 inches of rain, including in Houston where Johnson Space Center is located, resulting in floods impacting hundreds of thousands of homes and displacing more than 30,000 people. Harvey has caused at least 21 deaths in the United States. Preliminary economic losses are estimated to be between $10 billion to $160 billion.

While the Johnson Space Center originally closed on Aug. 25, sheltering in place were mission-essential personnel. This included flight controllers who maintain constant contact with the International Space Station.

Johnson Space Center’s leadership is continuing to monitor weather conditions as well as the overall situation in Houston. Teams will prepare a full assessment of the center’s status after the storm fully passes.

“Our primary concern is the safety of our employees and all our fellow Houstonians,” said Johnson Director Ellen Ochoa in a statement on NASA’s website. “We’re taking these measures to ensure the members of our team and their families can take care of themselves and their neighbors.”

According to NASA, closing the center will allow employees to avoid flooded roads and attend to the needs of their families. Additionally, it allows for essential employees to focus on the highest-priority missions, including the landing of three ISS crew members over the Labor Day weekend. The trio – Whitson, NASA astronaut Jack Fischer, and cosmonaut Fyodor Yurchikhin – will land in their Soyuz MS-04 spacecraft at 9:22 p.m. EDT Sept. 2 (01:22 GMT Sept. 3), 2017, in Kazakhstan.

Video courtesy of NOAA

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NASA Glenn experiments shedding new light on Venus’ shrouded surface

NASA Glenn experiments shedding new light on Venus’ shrouded surface:

The planet Venus is permanently shrouded by cloud cover. Photo Credit NASA

CLEVELAND, Ohio — A special NASA test chamber apparatus is helping scientists explore the mysteries of Venus right here on Earth. The chamber is located at NASA’s Glenn Research Center in Cleveland, Ohio. It is hoped that this new vessel will help prepare the space agency for missions to extreme worlds.

GEER, the Glenn Extreme Environment Rig, is a high-tech pressure vessel capable of simulating the pressure, temperature, and atmospheric gas mix of Venus, or any other extreme planetary environment, for an extended period. Engineers at the NASA Glenn Research Center where GEER is housed, as well as scientists from nearby Case Western Reserve University, recently conducted a long-duration experiment in GEER that could yield important new information about the Venus environment.

A computer generated global view of Venus, centered at 180° East longitude, based on the Magellan probe’s radar mapping. (Click to enlarge) Image Credit: NASA/JPL

The recent test, completed in mid-July, lasted for some 80 days; it served as the follow-up to a 40-day test that was conducted in GEER about two years ago.

“This is more about planetary science than spaceflight,” Ralph Harvey, a Professor in the department of Earth Environment and Planetary Science at Case Western Reserve University, told Spaceflight Insider. “We decided GEER gives us the opportunity to do a large volume experiment […] and that we would simulate the most reactive situation I could think of between the crust of Venus and the atmosphere. And that situation is when new rock is exposed – when volcanoes spit out a bit of lava.”

Surface radar images of Venus and the resulting topographic maps show an abundance of volcanoes and lava flows on the planet’s surface. Harvey and his graduate student Brandon Radoman-Shaw, in cooperation with researchers and engineers at NASA Glenn, conceived of an experiment in which they took a suite of minerals that represent the key minerals in basaltic volcanic rocks – pyroxene, olivine, feldspars, and others – as well as some glasses, and placed them inside the GEER chamber. There, the minerals were exposed to a high-fidelity simulation of Venus’ surface conditions – not only of the physical conditions but also of the atmospheric composition as well.

“The GEER chamber is an unparalleled thing,” Harvey said. “Other people have done experiments simulating the Venus surface, but they were always limited in terms of their own technology. Often the vessel in which they simulated the Venus surface conditions was the size of a soda can or a thermos bottle. Or their experiments had been limited in terms of the temperatures or pressures they could reach.”

The GEER chamber is much larger than a soda can. It is cylindrical in shape, 3-feet (91 cm) in diameter by 4-feet (122 cm) long. The complex apparatus surrounding the pressure vessel allows researchers to carefully create and monitor the simulated pressure, temperature, and gas mix conditions at Venus’ surface.

“It is the surface and the near surface where we know the least about Venus,” Harvey said. “Yet it has clearly played a major role in how the planet has evolved. If the rock is all reacted and weathered there at the surface, that would be really important to know about as you are designing instruments and analytical techniques to study that.”

The recent 80-day experiment, as well as the previous 40-day experiment, is designed to help understand how the Venus atmosphere and fresh rock might interact. The most recent experiment is still under fresh analysis, but some upcoming research abstracts suggest some of the early implications of the experiments.

Harvey said: “What we are learning so far is that, in spite of the fact that CO₂ is the greenhouse gas that everyone pays a lot of attention to, it is probably sulfur that is the real mover and shaker. We don’t see a lot of activity of carbon. In fact, it doesn’t look like CO₂-bearing or carbonate minerals are very stable at all. It looks like they go away rather than form.”

The effect of CO₂ on Venus has long been a topic of debate among scientists, given immediacy by the greenhouse effects of CO₂ and its possible connections to climate change on Earth. The lack of new data from Venus on the subject has kept the debate alive for decades. The new data from the recent GEER experiment may add a new and unforeseen twist to the debate.

“Sulfur looks like a much bigger player than CO₂,” Harvey said. “Even though the atmosphere is mostly CO₂ and that’s the big greenhouse gas you read about in all the papers, sulfur is a much more active greenhouse gas, and it forms a really nasty, very reactive acid. Even though sulfur is a minor component of that atmosphere, it is a major player in how rocks on Venus interact with the atmosphere.”

The analysis of the 80-day experiment is just beginning. It will be some time before its findings are included in papers for publication. Nevertheless, Harvey already believes the experiment is likely to provide a new perspective from which to approach future studies of the Venus surface environment.

“In some ways, we’re kind of wiping the slate clean,” he said. “We’re going to figure out what reactions are more important and which ones are less important. We’re not going to be super quantitative or come up with reaction rates or describe the history of Venus hour by hour for the next billion years. However, on the other hand, it creates a new starting point for more sophisticated modeling and more experiments.”

LEFT: Kyle Phillips, NASA Glenn engineer, removes samples from GEER after they were exposed to Venus surface conditions for 80 days. RIGHT: Professor Ralph Harvey and graduate student Brandon Radoman-Shaw of Case Western Reserve University inspect mineral samples used in the 80-day simulated Venus surface environment test in the GEER chamber at NASA Glenn Research Center in Cleveland, Ohio. Photos Credit: NASA

The recent 80-day experiment would not have been possible without some significant redesigns to the systems of GEER. Simulating the 863 °F (462 °C) temperatures and the extreme atmospheric pressure 90 times that of Earth that exists at Venus’ surface is a challenge to materials and engineering.

“We pretty much redesigned our entire process system, and that is everything but the GEER vessel itself,” Leah Nakely, Chemical Test Engineer and Lead Engineer for the GEER Project, told Spaceflight Insider. “All of the components, the lines, the subsystems were redesigned and checked out before the test.”

The GEER team did a materials study that was spread out over three different tests. The tests were over 10-day, 20-day, and 40-day periods. Those tests demonstrated what kind of component materials worked best to facilitate a Venus environment test, and they made their selection of component materials based on those results. The components included valves, heaters, sensors, gas mixers, flow meters, and tubing.

“So all of the components, the lines, the subsystems, were redesigned and checked out before the test,” Nakely said. “Some of the new capabilities we added were real-time gas analysis. And that’s a big one. That allows us to take gas samples directly from the GEER vessel and analyze them in just a couple of minutes, and know exactly what the gas composition is, and from there we can adjust it, add more gas, or adjust the chemical composition. That’s a big addition we made.”

That new capability was essential to extending the Venus surface condition test to an 80-day experiment. And the redesign with the severe service parts helped make that real-time gas analysis capability possible.

“Some materials that perform really well on Earth do not perform well on Venus,” Nakely said. “No one really knows what will perform well on Venus. That’s what GEER is for.”

“I can guarantee you every time we run something in GEER we see something that makes our jaws drop,” Harvey added. “Things just aren’t behaving in the way your intuition based on Earth would lead you to expect. And whether you are a scientist or an engineer, that’s always cool.”

GEER, the Glenn Extreme Environment Rig, with its chamber open prior to an experiment. A 40-day test in simulated Venus surface conditions was conducted in the chamber two years ago, and an 80-day test was completed this past July. Scientists at Case Western Reserve University in Cleveland, Ohio, exposed a number of basaltic volcanic minerals to the simulated Venus environment to observe and analyze their reaction. An experiment in GEER’s simulated Venus environment was also completed earlier this year, testing the durability of silicon carbide semiconductor circuits, which may be used in instrumentation for future missions to Venus’ surface. Photo Credit: NASA Glenn

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Ariane 5 to launch 2 satellites to geostationary transfer orbit

Ariane 5 to launch 2 satellites to geostationary transfer orbit:

Intelsat37e is one of two satellites an Ariane 5 will send into orbit for the mission designated VA239. Image Credit: Arianespace

For the fifth time in 2017, Arianespace will send an Ariane 5 rocket into space. The flight will orbit commercial communication satellites for two international customers: Intelsat and Broadcasting Satellite System Corporation (B-SAT), a leading broadcasting satellite operator in Japan.

The Intelsat 37e satellite will support Africa, Europe, Central Africa, and Latin America, while BSAT-4a will provide Direct-to-Home (DTH) television service in Japan.

Improving satcom capabilities

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Stationed in geosynchronous orbit at 342° E longitude, Intelsat 37e will be situated over the mid-Atlantic. Weighing in at a hefty 14,193 pounds (6,438 kilograms), the satellite is the fifth of Intelsat’s EpicNG series of high-throughput satellites built by Boeing.

Intelsat 37e includes fixed C-band, and steerable spot Ku-band and Ka-band beams, which allows the spacecraft to optimize its services to meet the requirements of its regional customers. It is the first satellite to offer interconnectivity between three different bands. Additionally, the next-generation satellite will be used in wireless backhaul, enterprise Very Small Aperture Terminal (VSAT), and mobility networks.

The satellite Intelsat 37e is replacing, Intelsat 901, was launched in 2001 and has exceeded its estimated 13-year service life.

BSAT-4a is Arianespace’s ninth launch for B-SAT and its 30th launch contract for a geostationary commercial satellite in Japan. The 7,760-pound (3,520-kilogram) satellite, which will be stationed over the equator at 110° E, carries 24 Ku-band transponders. It will expand the availability of high-definition and 4K/8K ultra-high-definition television in that country. The spacecraft bus is based on SSL‘s SSL 1300 platform.

Both satellites are designed to provide service for 15 years or longer.

Ready to go

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On Sept. 1, 2017, the Ariane 5 ECA flight, designated VA239 by Arianespace, was cleared for launch. The rocket will roll out from the Guiana Space Centre’s Final Assembly Building in Kourou, French Guiana Sept. 4 to the ELA-3 launch zone.

Liftoff will occur Sept. 5, with a 33-minute launch window opening at 6:51 p.m. local time in French Guiana (5:51 p.m. EDT / 21:51 GMT). After achieving an initial orbit, Intelsat 37e, as the top payload “passenger”, will be deployed first, followed by BSAT-4a.

BSAT-4a is one of two satellites an Ariane 5 will send into orbit for the mission designated VA239. Image Credit: Arianespace

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