Thursday, June 14, 2018

Across The Universe- Listen to the Eerie Whistling 'Chorus' That's Supercharging Radiation Near Earth

Listen to the Eerie Whistling 'Chorus' That's Supercharging Radiation Near Earth: The blazing-fast particles that whirl through Earth's radiation belts are propelled mostly by whistling "chorus" waves, according to new research from two NASA satellite missions.


Original enclosures:

Across The Universe- Hubble Catches a Spiral Galaxy in Disguise

Hubble Catches a Spiral Galaxy in Disguise: NGC 1032 cleaves the quiet darkness of space in two in this image from the NASA/ESA Hubble Space Telescope.


Original enclosures:

Across The Universe- Hubble Images a Galaxy with Threads of Blue

Hubble Images a Galaxy with Threads of Blue: A ripple of bright blue gas threads through this galaxy like a misshapen lake system.


Original enclosures:


Across The Universe- The Clash of NGC 3256

The Clash of NGC 3256:

Discover the cosmos!
Each day a different image or photograph of our fascinating universe is
featured, along with a brief explanation written by a professional astronomer.


2018 June 7




See Explanation.  Clicking on the picture will download the highest resolution version available.
Explanation:

Marked by an unusually bright central region, swirling dust lanes,
and far flung tidal tails, peculiar NGC 3256 is the aftermath of a
truly
cosmic collision
.

The 500 million year old clash of two separate galaxies spans
some 100 thousand light-years in
this
sharp Hubble view
.

Of course when two galaxies collide, individual stars rarely do.

Giant galactic clouds of
molecular gas
and dust do interact though, and produce spectacular bursts of
star formation.

In this
galaxy clash,
the two original spiral galaxies had similar masses.

Their disks are no longer distinct and the two galactic nuclei
are hidden by obscuring dust.

On the timescale of a few hundred million years the nuclei
will likely also merge
as
NGC 3256
becomes a single large elliptical galaxy.

NGC 3256 itself is nearly 100 million light-years distant toward
the southern sailing constellation Vela.

The frame includes many even more distant background galaxies and
spiky foreground stars.

Across The Universe- The Cats Eye Nebula from Hubble

The Cats Eye Nebula from Hubble:

Discover the cosmos!
Each day a different image or photograph of our fascinating universe is
featured, along with a brief explanation written by a professional astronomer.


2018 June 10




See Explanation.  Clicking on the picture will download the highest resolution version available.


The Cat's Eye Nebula from Hubble

Image Credit:
NASA,
ESA,
HEIC, and
The Hubble Heritage Team
(STScI/AURA)


Explanation:
To some, it may look like a cat's eye.

The
alluring Cat's Eye
nebula, however, lies three thousand light-years from Earth across interstellar space.

A classic
planetary
nebula
, the Cat's Eye (NGC 6543) represents a final, brief
yet
glorious phase
in the life of a sun-like star.

This nebula's dying central star may have produced the simple,
outer pattern of dusty
concentric shells
by shrugging off
outer
layers in a series of regular convulsions.

But the formation of the beautiful, more complex
inner structures is not well understood.

Seen so clearly in
this digitally sharpened Hubble Space Telescope image,
the truly cosmic eye is over half a
light-year across.

Of course,
gazing into this Cat's Eye,
astronomers may well be seeing
the fate of our sun, destined to enter its own
planetary nebula
phase
of evolution ... in about 5 billion years.




Tomorrow's picture: a long time ago




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Authors & editors:
Robert Nemiroff
(MTU) &
Jerry Bonnell (UMCP)
NASA Official: Phillip Newman
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ASD at
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Across The Universe- Okay, Last Year’s Kilonova Did Probably Create a Black Hole

Okay, Last Year’s Kilonova Did Probably Create a Black Hole:

In August of 2017, another major breakthrough occurred when the Laser Interferometer Gravitational-Wave Observatory (LIGO) detected waves that were believed to be caused by a neutron star merger. Shortly thereafter, scientists at LIGO, Advanced Virgo, and the Fermi Gamma-ray Space Telescope were able to determine where in the sky this event (known as a kilonova) occurred.

This source, known as GW170817/GRB, has been the target of many follow-up surveys since it was believed that the merge could have led to the formation of a black hole. According to a new study by a team that analyzed data from NASA’s Chandra X-ray Observatory since the event, scientists can now say with greater confidence that the merger created a new black hole in our galaxy.

The study, titled “GW170817 Most Likely Made a Black Hole“, recently appeared in The Astrophysical Journal Letters. The study was led by David Pooley, an assistant professor in physics and astronomy at Trinity University, San Antonio, and included members from the University of Texas at Austin, the University of California, Berkeley, and Nazarbayev University’s Energetic Cosmos Laboratory in Kazakhstan.





Illustration of the kilonova merger (top), and the resulting object (left and right) over time. Credit: NASA/CXC/Trinity University/D. Pooley et al. Illustration: NASA/CXC/M.Weiss
For the sake of their study, the team analyzed X-ray data from Chandra taken in the days, weeks, and months after the detection of gravitational waves by LIGO and gamma rays by NASA’s Fermi mission. While nearly every telescope in the world had observed the source, X-ray data was critical to understanding what happened after the two neutron stars collided.

While a Chandra observation two to three days after the event failed to detect an X-ray source, subsequent observations taken 9, 15, and 16 days after the event resulted in detections. The source disappeared for a time as GW170817 passed behind the Sun, but additional observations were made about 110 and 160 days after the event, both of which showed significant brightening.

While the LIGO data provided astronomers with a good estimate of the resulting object’s mass after the neutron stars merged (2.7 Solar Masses), this was not enough to determine what it had become. Essentially, this amount of mass meant that it was either the most massive neutron star ever found or the lowest-mass black hole ever found (the previous record holders being four or five Solar Masses). As Dave Pooley explained in a NASA/Chandra press release:

“While neutron stars and black holes are mysterious, we have studied many of them throughout the Universe using telescopes like Chandra. That means we have both data and theories on how we expect such objects to behave in X-rays.”




Illustration of the resulting black hole caused by GW170817. Credit: NASA/CXC/M.Weiss
If the neutron stars merged to form a heavier neutron star, then astronomers would expect it to spin rapidly and generate and very strong magnetic field. This would have also created an expanded bubble of high-energy particles that would result in bright X-ray emissions. However, the Chandra data revealed X-ray emissions that were several hundred times lower than expected from a massive, rapidly-spinning neutron star.

By comparing the Chandra observations with those by the NSF’s Karl G. Jansky Very Large Array (VLA), Pooley and his team were also able to deduce that the X-ray emission were due entirely to the shock wave caused by the merger smashing into surrounding gas. In short, there was no sign of X-rays resulting from a neutron star.

This strongly implies that the resulting object was in fact a black hole. If confirmed, these results would indicate that the formation process of a blackhole can sometimes be complicated. Essentially, GW170817 would have been the result of two stars undergoing a supernova explosion that left behind two neutron stars in a sufficiently tight orbit that they eventually came together. As Pawan Kumar explained:

“We may have answered one of the most basic questions about this dazzling event: what did it make? Astronomers have long suspected that neutron star mergers would form a black hole and produce bursts of radiation, but we lacked a strong case for it until now.”




Simulated view of a black hole. Credit: Bronzwaer/Davelaar/Moscibrodzka/Falcke, Radboud University
Looking ahead, the claims put forward by Pooley and his colleagues could be tested by future X-ray and radio observations. Next-generation instruments – like the Square Kilometer Array (SKA) currently under construction in South Africa and Australia, and the ESA’s Advanced Telescope for High-ENergy Astrophysics (Athena+) – would be especially helpful in this regard.

If the remnant turns out to be a massive neutron star with a strong magnetic field after all, then the source should get much brighter in the X-ray and radio wavelengths in the coming years as the high-energy bubble catches up with the decelerating shock wave. As the shock wave weakens, astronomers expect that it will continue to become fainter than it was when recently observed.

Regardless, future observations of GW170817 are bound to provide a wealth of information, according to J. Craig Wheeler, a co-author on the study also from the University of Texas. “GW170817 is the astronomical event that keeps on giving,” he said. “We are learning so much about the astrophysics of the densest known objects from this one event.”

If these follow-up observations find that a heavy neutron star is what resulted from the merger, this discovery would challenge theories about the structure of neutron stars and how massive they can get. On the other hand, if they find that it formed a tiny black hole, then it will challenge astronomers notions about the lower mass limits of black holes. For astrophysicists, it’s basically a win-win scenario.

As co-author Bruce Grossan of the University of California at Berkeley added:

“At the beginning of my career, astronomers could only observe neutron stars and black holes in our own galaxy, and now we are observing these exotic stars across the cosmos. What an exciting time to be alive, to see instruments like LIGO and Chandra showing us so many thrilling things nature has to offer.”
Indeed, looking farther out into the cosmos and deeper back in time has revealed much about the Universe that was previously unknown. And with improved instruments being developed for the sole purpose of studying astronomical phenomena in greater detail and at even greater distances, there seems to be no limit to what we might learn. And be sure to check out this video of the GW170817 merger, courtesy of the Chandra X-ray Observatory:



Further Reading: Chandra, The Astrophysical Journal Letters

The post Okay, Last Year’s Kilonova Did Probably Create a Black Hole appeared first on Universe Today.

Across The Universe- Globular Clusters Might not be as Old as Astronomers Thought. Like, Billions of Years Younger

Globular Clusters Might not be as Old as Astronomers Thought. Like, Billions of Years Younger:

Globular clusters have been a source of fascination ever since astronomers first observed them in the 17th century. These spherical collections of stars are among the oldest known stars in the Universe, and can be found in the outer regions of most galaxies. Because of their age and the fact that almost all larger galaxies appear to have them, their role in galactic evolution has remained something of a mystery.

Previously, astronomers were of the opinion that globular clusters were some of the earliest stars to have formed in the Universe, roughly 13 billion years ago. However, new research has indicated that these clusters may actually be about 4 billion years younger, being roughly 9 billion years old. These findings may alter our understanding of how the Milky Way and other galaxies formed, and how the Universe itself came to be.

The study, titled “Reevaluating Old Stellar Populations“, recently appeared online and is being evaluated for publication in The Monthly Notices for the Royal Astronomical Society. The study was led by Dr. Elizabeth Stanway, an Associate Professor in the Astronomy group at the University of Warwick, UK, and was assisted by Dr. J.J. Eldridge, a Senior Lecturer at the University of Auckland, New Zealand.





Within larger galaxies, like the Milky Way, globular clusters are part of the galactic halo. Between 150 and 180 are estimated to be part of the Milky Way alone. Credit: ESO
For the sake of their study, Dr. Stanway and Dr. Eldridge developed a series of new research models designed to reconsider the evolution of stars. These models, known as Binary Population and Spectral Synthesis (BPASS) models, had previously proven effective in exploring the properties of young stellar populations within the Milky Way and throughout the Universe.

Using these same models, Dr. Stanway and Dr. Eldridge studied a sample of globular clusters in the Milky Way and nearby quiescent galaxies. They also took into account the details of binary star evolution within globular clusters and used them to explore the colors of light and spectra from old binary populations. In short, binary star system evolution consists of one star expanding into a giant while the gravitational force of the smaller star strips away the atmosphere of the giant.

What they found was that these binary systems were about 9 billion years old. Since these stars are thought to have formed at the same time as the globular clusters themselves, this demonstrated that globular clusters are not as old as other models have suggested. As Dr. Stanway said of the BPASS models she and Dr. Eldridge developed:

“Determining ages for stars has always depended on comparing observations to the models which encapsulate our understanding of how stars form and evolve. That understanding has changed over time, and we have been increasingly aware of the effects of stellar multiplicity – the interactions between stars and their binary and tertiary companions.




An artist’s impression of a millisecond pulsar and its companion. The presence of binaries in globular clusters is a good means of providing age estimates of those clusters. Credit: ESA & Francesco Ferraro (Bologna Astronomical Observatory)
If correct, this study could open up new pathways of research into how massive galaxies and their stars are formed. However, Dr. Stanway admits that much work still lies ahead, which includes looking at nearby star systems where individual stars can be resolved – rather than considering the integrated light of a cluster. Nevertheless, the study could have immense significant for our understanding of how and when galaxies in our Universe formed.

“If true, it changes our picture of the early stages of galaxy evolution and where the stars that have ended up in today’s massive galaxies, such as the Milky Way, may have formed,” she said. “We aim to follow up this research in the future, exploring both improvements in modelling and the observable predictions which arise from them.”

An integral part of cosmology is understanding when the Universe came to be the way it is, not just how. By determining how old globular clusters are, astronomers will have another crucial piece of the puzzle as to how and when the earliest galaxies formed. And these, combined with observations that look to the earliest epochs of the Universe, could just yield a complete model of cosmology.

Further Reading: University of Warwick, arXiv

The post Globular Clusters Might not be as Old as Astronomers Thought. Like, Billions of Years Younger appeared first on Universe Today.

Across The Universe- Astro Challenge: Spotting 4 Vesta at its Best for Decades

Astro Challenge: Spotting 4 Vesta at its Best for Decades:



Vesta


The brave new world of 4 Vesta, courtesy of NASA’s Dawn spacecraft. Credit: NASA/JPL-Caltech/UCAL/MPS/DLR/IDA
Up for a challenge? Planetary action is certainly heating up this summer: Jupiter passed opposition last month, Saturn does so in June, and Mars reaches favorable viewing next month. And with dazzling Venus in the west and Mercury to joining it starting in late June, we’ll soon have all of the naked eye classical planets in the evening sky.

Now, I want to turn your attention towards a potential naked eye object, one you’ve probably never seen: asteroid 4 Vesta.



Vesta


Vesta and the planet(s)… looking east in early June, about 45 minutes after sunset. Stellarium.
Vistas of Vesta

Vesta reaches opposition in 2018 on the night of June 19th. At 1.14 Astronomical Units (AU, 170.8 million kilometers) distant, this year’s opposition is slightly more favorable than any other since 1989. We won’t get another pass nearly as close until May 2036. Vesta orbits the Sun once every 3.6 years, ranging from a perihelion of 2.15 AU to an aphelion of 2.57 AU.

Although Vesta was the fourth asteroid discovered, it’s actually the brightest, and the only one visible with the naked eye—that is, if you have dark skies, and know exactly where to look for it. This summer, Vesta loiters in the star rich realm of the astronomical constellation Sagittarius, “in the weeds” for viewers up north, but high in the sky for southern viewers.



Vesta


The path of 4 Vesta through mid-September. Credit: Starry Night Education software.
Early June finds Vesta about 5 degrees northwest of the +3.8 magnitude star Mu Sagittarii, threading between the deep sky objects Messier 24 and Messier 25. Vesta then loops westward through the constellation Ophiuchus the Serpent Bearer starting on July 1st, before heading back to Sagittarius on September 5th.

Vesta in 2018

Catching Vesta with the naked eye isn’t easy. You’ll need dark rural skies with a limiting magnitude down to about +5.5, and a good beforehand knowledge of the fixed stars in the region. Vesta also spends 2018 weaving around the star-dappled plane of the Milky Way galaxy, making it an especially challenging target.

Binoculars or a telescope can bring the challenge within reach of suburban and urban skies, making it a pleasure to trace the track of Vesta from night to night. Sketch the background star field and you just might tease out the presence of Vesta as it slowly moves about 30′ arcminutes per night (the diameter of a Full Moon) through June. Crank up the magnification a bit using a large (10 inches aperture or greater) light bucket telescope, and you just might see the faint hint of an oblong disk… 348 by 277 miles (560 by 446 kilometers) in size, Vesta’s apparent size is 0.7” arcseconds around opposition, 1/3 the size of Neptune at its best.



occultation vesta


The occultation footprint for the June 27th event. Credit: Occult 4.2 software.
The 99% illuminated, waxing gibbous Moon will actually occult 4 Vesta for Hawaii, Central America and the Galapagos Islands just eight days after opposition on the night of June 27th.



ceres vesta


Ceres (left) and Vesta (right) imaged by the Hubble Space Telescope. Credit: NASA/HST/STl
Discovered on the night of March 29th, 1807 by prolific asteroid hunter Heinrich Olber, the Hubble Space Telescope gave us our first blurry images of 4 Vesta back in 2007. NASA’s Dawn spacecraft gave us our first good views of Vesta as a world starting in mid- 2011, orbiting the potato-shaped asteroid for just over a year before departing for 1 Ceres in late 2012.





The south pole Rheasilvia impact basin. Based on images obtained by NASA’s Dawn spacecraft, the lower false color map shows the elevation scale scooped out by an ancient impact. Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA/PSI
Attack of the Vestoid(s)

And did you know: we actually have identified samples of Vesta to study, right here on Earth. Vesta sustained a massive impact about a billion years ago, raining debris through the inner solar system. Dawn chronicled the resulting Rheasilvia impact basin on Vesta’s south pole, and asteroids such as 1981 Midas match the spectral composition of Vesta and are collectively known as “Vestoids”.



Vesta Meteorites


Meteorites recovered on Earth, courtesy of 4 Vesta. Credit: NASA/University of Tennessee.
On Earth, meteorites such as QUE 97053 found in Antarctica and the 1913 Moore County fall in North Carolina also match up in composition to Vesta, and make up a subgroup known as Howardite-Eucrite-Diogenite (HED) meteorites. Collectively, space rocks from this single impact on 4 Vesta contribute to an amazing 5% of all the meteorites recovered on Earth.

Fascinating thoughts to ponder, as we follow the brightest asteroid through the summer sky.

The post Astro Challenge: Spotting 4 Vesta at its Best for Decades appeared first on Universe Today.

Across The Universe- Are There Enough Chemicals on Icy Worlds to Support Life?

Are There Enough Chemicals on Icy Worlds to Support Life?:

For decades, scientists have believed that there could be life beneath the icy surface of Jupiter’s moon Europa. Since that time, multiple lines of evidence have emerged that suggest that it is not alone. Indeed, within the Solar System, there are many “ocean worlds” that could potentially host life, including Ceres, Ganymede, Enceladus, Titan, Dione, Triton, and maybe even Pluto.

But what if the elements for life as we know it are not abundant enough on these worlds? In a new study, two researchers from the Harvard Smithsonian Center of Astrophysics (CfA) sought to determine if there could in fact be a scarcity of bioessential elements on ocean worlds. Their conclusions could have wide-ranging implications for the existence of life in the Solar System and beyond, not to mention our ability to study it.

The study, titled “Is extraterrestrial life suppressed on subsurface ocean worlds due to the paucity of bioessential elements?” recently appeared online. The study was led by Manasvi Lingam, a postdoctoral fellow at the Institute for Theory and Computation (ITC) at Harvard University and the CfA, with the support of Abraham Loeb – the director of the ITC and the Frank B. Baird, Jr. Professor of Science at Harvard.





Artist’s depiction of a watery exoplanet orbiting a distant red dwarf star. Credit: CfA
In previous studies, questions on the habitability of moons and other planets have tended to focus on the existence of water. This has been true when it comes to the study of planets and moons within the Solar System, and especially true when it comes the study of extra-solar planets. When they have found new exoplanets, astronomers have paid close attention to whether or not the planet in question orbits within its star’s habitable zone.

This is key to determining whether or not the planet can support liquid water on its surface. In addition, astronomers have attempted to obtain spectra from around rocky exoplanets to determine if water loss is taking place from its atmosphere, as evidenced by the presence of hydrogen gas. Meanwhile, other studies have attempted to determine the presence of energy sources, since this is also essential to life as we know it.

In contrast, Dr. Lingam and Prof. Loeb considered how the existence of life on ocean planets could be dependent on the availability of limiting nutrients (LN). For some time, there has been considerable debate as to which nutrients would be essential to extra-terrestrial life, since these elements could vary from place to place and over timescales. As Lingam told Universe Today via email:

“The mostly commonly accepted list of elements necessary for life as we know it comprises of hydrogen, oxygen, carbon, nitrogen and sulphur. In addition, certain trace metals (e.g. iron and molybdenum) may also be valuable for life as we know it, but the list of bioessential trace metals is subject to a higher degree of uncertainty and variability.”




Artist rendering showing an interior cross-section of the crust of Enceladus, which shows how hydrothermal activity may be causing the plumes of water at the moon’s surface. Credits: NASA-GSFC/SVS, NASA/JPL-Caltech/Southwest Research Institute
For their purposes, Dr. Lingam and Prof. Loeb created a model using Earth’s oceans to determine how the sources and sinks – i.e. the factors that add or deplete LN elements into oceans, respectively – could be similar to those on ocean worlds. On Earth, the sources of these nutrients include fluvial (from rivers), atmospheric and glacial sources, with energy being provided by sunlight.

Of these nutrients, they determined that the most important would be phosphorus, and examined how abundant this and other elements could be on ocean worlds, where conditions as vastly different. As Dr. Lingam explained, it is reasonable to assume that on these worlds, the potential existence of life would also come down to a balance between the net inflow (sources) and net outflow (sinks).

“If the sinks are much more dominant than the sources, it could indicate that the elements would be depleted relatively quickly. In other to estimate the magnitudes of the sources and sinks, we drew upon our knowledge of the Earth and coupled it with other basic parameters of these ocean worlds such as the pH of the ocean, the size of the world, etc. known from observations/theoretical models.”

While atmospheric sources would not be available to interior oceans, Dr. Lingam and Prof. Loeb considered the contribution played by hydrothermal vents. Already, there is abundant evidence that these exist on Europa, Enceladus, and other ocean worlds. They also considered abiotic sources, which consist of minerals leached from rocks by rain on Earth, but would consist of the weathering of rocks by these moons’ interior oceans.





Artist’s rendering of possible hydrothermal activity that may be taking place on and under the seafloor of Enceladus. Credit: NASA/JPL
Ultimately, what they found was that, unlike water and energy, limiting nutrients might be in limited supply when it comes to ocean worlds in our Solar System:

“We found that, as per the assumptions in our model, phosphorus, which is one of the bioessential elements, is depleted over fast timescales (by geological standards) on ocean worlds whose oceans are neutral or alkaline in nature, and which possess hydrothermal activity (i.e. hydrothermal vent systems at the ocean floor). Hence, our work suggests that life may exist in low concentrations globally in these ocean worlds (or be present only in local patches), and may therefore not be easily detectable.”
This naturally has implications for missions destined for Europa and other moons in the outer Solar System. These include the NASA Europa Clipper mission, which is currently scheduled to launch between 2022 and 2025. Through a series of flybys of Europa, this probe will attempt to measure biomarkers in the plume activity coming from the moon’s surface.

Similar missions have been proposed for Enceladus, and NASA is also considering a “Dragonfly” mission to explore Titan’s atmosphere, surface and methane lakes. However, if Dr. Lingam and Prof. Loeb’s study is correct, then the chances of these missions finding any signs of life on an ocean world in the Solar System are rather slim. Nevertheless, as Lingam indicated, they still believe that such missions should be mounted.





Artist’s concept of a Europa Clipper mission. Credit: NASA/JPL
“Although our model predicts that future space missions to these worlds might have low chances of success in terms of detecting extraterrestrial life, we believe that such missions are still worthy of being pursued,” he said. “This is because they will offer an excellent opportunity to: (i) test and/or falsify the key predictions of our model, and (ii) collect more data and improve our understanding of ocean worlds and their biogeochemical cycles.”

In addition, as Prof. Loeb indicated via email, this study was focused on “life as we know it”. If a mission to these worlds did find sources of extra-terrestrial life, then it would indicate that life can arise from conditions and elements that we are not familiar with. As such, the exploration of Europa and other ocean worlds is not only advisable, but necessary.

“Our paper shows that elements that are essential for the ‘chemistry-of-life-as-we-know-it’, such as phosphorous, are depleted in subsurface oceans,” he said. “As a result, life would be challenging in the oceans suspected to exist under the surface ice of Europa or Enceladus. If future missions confirm the depleted level of phosphorous but nevertheless find life in these oceans, then we would know of a new chemical path for life other than the one on Earth.”

In the end, scientists are forced to take the “low-hanging fruit” approach when it comes to searching for life in the Universe . Until such time that we find life beyond Earth, all of our educated guesses will be based on life as it exists here. I can’t imagine a better reason to get out there and explore the Universe than this!

Further Reading: arXiv

The post Are There Enough Chemicals on Icy Worlds to Support Life? appeared first on Universe Today.

Across The Universe- Breakthrough Starshot is Now Looking for the Companies to Build its Laser-Powered Solar Sails to Other Stars

Breakthrough Starshot is Now Looking for the Companies to Build its Laser-Powered Solar Sails to Other Stars:

In 2015, Russian billionaire Yuri Milner established Breakthrough Initiatives, a non-profit organization dedicated to enhancing the search for extraterrestrial intelligence (SETI). In April of the following year, he and the organization be founded announced the creation of Breakthrough Starshot, a program to create a lightsail-driven “wafercraft” that would make the journey to the nearest star system – Proxima Centauri – within our lifetime.

In the latest development, on Wednesday May 23rd, Breakthrough Starshot held an “industry day” to outline their plans for developing the Starshot laser sail. During this event, the Starshot committee submitted a Request For Proposals (RFP) to potential bidders, outlining their specifications for the sail that will carry the wafercraft as it makes the journey to Proxima Centauri within our lifetimes.

As we have noted in several previous articles, Breakthrough Starshot calls for the creation of a gram-scale nanocraft being towed by a laser sail. This sail will be accelerated by an Earth-based laser array to a velocity of about 60,000 km/s (37,282 mps) – or 20% the speed of light (o.2 c). This concept builds upon the idea of a solar sail, a spacecraft that relies on solar wind to push itself through space.





An artist’s illustration of a light-sail powered by a radio beam (red) generated on the surface of a planet. Credit: M. Weiss/CfA
At this speed, the nanocraft would be able to reach the closest star system to our own – Proxima Centauri, located 4.246 light-years away – in just 20 years time. Since its inception, the team behind Breakthrough Starshot has invested considerable time and energy addressing the conceptual and engineering challenges such a mission would entail. And with this latest briefing, they are now looking to move the project from concept to reality.

In addition to being the Frank B. Baird, Jr. Professor of Science at Harvard University, Abraham Loeb is also the Chair of the Breakthrough Starshot Advisory Committee. As he explained to Universe Today via email:

“Starshot is an initiative to send a probe to the nearest star system at a fifth of the speed of light so that it will get there within a human lifetime of a couple of decades. The goal is to obtain photos of exo-planets like Proxima b, which is in the habitable zone of the nearest star Proxima Centauri, four light years away. The technology adopted for fulfilling this challenge uses a powerful (100 Giga-watt) laser beam pushing on a lightweight (1 gram) sail to which a lightweight electronics chip is attached (with a camera, navigation and communication devices). The related technology development is currently funded at $100M by Yuri Milner through the Breakthrough Foundation.”
In addition to outlining BI’s many efforts to find ETI – which include Breakthrough Listen, Breakthrough Message and Breakthrough Watch – the RFP focused on Starshot’s Objectives. As was stated in the RFP:

“The scope of this RFP addresses the Technology Development phase – to explore LightSail concepts, materials, fabrication and measurement methods, with accompanying analysis and simulation that creates advances toward a viable path to a scalable and ultimately deployable LightSail.”




A phased laser array, perhaps in the high desert of Chile, propels sails on their journey. Credit: Breakthrough Initiatives
As Loeb indicated, this RFP comes not long after another “industry day” that was related to the development of the technology of the laser – termed the “Photon Engine”. In contrast, this particular RFP was dedicated to the design of the laser sail itself, which will carry the nanocraft to Proxima Centauri.

“The Industry Day was intended to inform potential partners about the project and request for proposals (RFP) associated with research on the sail materials and design,” added Loeb. “Within the next few years we hope to demonstrate the feasibility of the required sail and laser technologies. The project will allocate funds to experimental teams who will conduct the related research and development work. ”

The RFP also addressed Starshot’s long-term goals and its schedule for research and development in the coming years. These include the investment in $100 million over the next five years to determine the feasibility of the laser and sail, to invest the value of the European Extremely Large Telescope (EELT) from year 6 to year 11 and build a low-power prototype for space testing, and invest the value of the Large Hardon Collider (LHC) over a 20 year period to develop the final spacecraft.

“The European Extremely Large Telescope (EELT) will cost on order of a billion [dollars] and the Large Hadron Collider cost was ten times higher,’ said Loeb. “These projects were mentioned to calibrate the scale of the cost for the future phases in the Starshot project, where the second phase will involve producing a demo system and the final step will involve the complete launch system.”





Artist’s impression of Proxima b, which was discovered using the Radial Velocity method. Credit: ESO/M. Kornmesser
The research and development schedule for the sail was also outlined, with three major phases identified over the next 5 years. Phase 1 (which was the subject of the RFP) would entail the development of concepts, models and subscale testing. Phase 2 would involve hardware validation in a laboratory setting, while Phase 3 would consist of field demonstrations.

With this latest “industry day” complete, Starshot is now open for submissions from industry partners looking to help them realize their vision. Step A proposals, which are to consist of a five-page summary, are due on June 22nd and will be assessed by Harry Atwater (the Chair of the Sail Subcommittee) as well as Kevin Parkin (head of Parkin Research), Jim Benford (muWave Sciences) and Pete Klupar (the Project Manager).

Step B proposals, which are to consist of a more detailed, fifteen-page summary, will be due on July 10th. From these, the finalists will be selected by Pete Worden, the Executive Director of Breakthrough Starshot. If all goes according to plan, the initiative hopes to launch the first lasersail-driven nanocraft in to Proxima Centauri in 30 years and see it arrive there in 50 years.

So if you’re an aerospace engineer, or someone who happens to run a private aerospace firm, be sure to get your proposals ready! To learn more about Starshot, the engineering challenges they are addressing, and their research, follow the links provided to the BI page. To see the slides and charts from the RFP, check out Starshot’s Solicitations page.

Further Reading: Centauri Dreams, Breakthrough Starshot

The post Breakthrough Starshot is Now Looking for the Companies to Build its Laser-Powered Solar Sails to Other Stars appeared first on Universe Today.

Across The Universe- Astronomy Cast Ep. 490: What’s New with Supernovae

Astronomy Cast Ep. 490: What’s New with Supernovae:



Time for another update, this time we’re going to look at what’s new with supernovae. And once again, we’ve got good news, lots of new stuff to report.

We usually record Astronomy Cast every Friday at 3:00 pm EST / 12:00 pm PST / 20:00 PM UTC. You can watch us live on AstronomyCast.com, or the AstronomyCast YouTube page.

Visit the Astronomy Cast Page to subscribe to the audio podcast!

If you would like to support Astronomy Cast, please visit our page at Patreon here – https://www.patreon.com/astronomycast. We greatly appreciate your support!

If you would like to join the Weekly Space Hangout Crew, visit their site here and sign up. They’re a great team who can help you join our online discussions!

The post Astronomy Cast Ep. 490: What’s New with Supernovae appeared first on Universe Today.

Across The Universe - One Way to Find Aliens Would be to Search for Artificial Rings of Satellites: Clarke Belts

One Way to Find Aliens Would be to Search for Artificial Rings of Satellites: Clarke Belts:

When it comes to the search for extra-terrestrial intelligence (SETI) in the Universe, there is the complicated matter of what to be on the lookout for. Beyond the age-old question of whether or not intelligent life exists elsewhere in the Universe (statistically speaking, it is very likely that it does), there’s also the question of whether or not we would be able to recognize it if and when we saw it.

Given that humanity is only familiar with one form of civilization (our own), we tend to look for indications of technologies we know or which seem feasible. In a recent study, a researcher from the Instituto de Astrofísica de Canarias (IAC) proposed looking for large bands of satellites in distant star systems – a concept that was proposed by the late and great Arthur C. Clarke (known as a Clarke Belt).

The study – titled “Possible Photometric Signatures of Moderately Advanced Civilizations: The Clarke Exobelt” – was conducted by Hector Socas-Navarro, an astrophysicist with the IAC and the Universidad de La Laguna. In it, he advocates using next-generation telescopes to look for signs of massive belts of geostationary communication satellites in distant star systems.



This proposal is based in part on a paper written by Arthur C. Clarke in 1945 (titled “Peacetime Uses for V2“), in which he proposed sending “artificial satellites” into geostationary orbit around Earth to create a global communications network. At present, there are about 400 such satellites in the “Clarke Belt” – a region named in honor of him that is located 36,000 km above the Earth.

This network forms the backbone of modern telecommunications and in the future, many more satellites are expected to be deployed – which will form the backbone of the global internet. Given the practicality of satellites and the fact that humanity has come to rely on them so much, Socas-Navarro considers that a belt of artificial satellites could naturally be considered “technomarkers” (the analogues of “biomarkers”, which indicate the presence of life).

As Socas-Navarro explained to Universe Today via email:

“Essentially, a technomarker is anything that we could potentially observe which would reveal the presence of technology elsewhere in the Universe. It’s the ultimate clue to find intelligent life out there. Unfortunately, interstellar distances are so great that, with our current technology, we can only hope to detect very large objects or structures, something comparable to the size of a planet.”
In this respect, a Clarke Exobelt is not dissimilar from a Dyson Sphere or other forms of megastructures that have been proposed by scientists in the past. But unlike these theoretical structures, a Clarke Exobelt is entirely feasible using present-day technology.





Graphic showing the cloud of space debris that currently surrounds the Earth. Credit: NASA’s Goddard Space Flight Center/JSC
“Other existing technomarkers are based on science fiction technology of which we know very little,” said Socas-Navarro. “We don’t know if such technologies are possible or if other alien species might be using them. The Clarke Exobelt, on the other hand, is a technomarker based on real, currently existing technology. We know we can make satellites and, if we make them, it’s reasonable to assume that other civilizations will make them too.”

According to Socas-Navarro, there is some “science fiction” when it comes to Clarke Exobelts that would actually be detectable using these instruments. As noted, humanity has about 400 operational satellites occupying Earth’s “Clarke Belt”. This is about one-third of the Earth’s existing satellites, whereas the rest are at an altitude of 2000 km (1200 mi) or less from the surface – the region known as Low Earth Orbit (LEO).

This essentially means that aliens would need to have billions more satellites within their Clarke Belt – accounting for roughly 0.01% of the belt area – in order for it to be detectable. As for humanity, we are not yet to the point where our own Belt would be detectable by an extra-terrestrial intelligence (ETI). However, this should not take long given that the number of satellites in orbit has been growing exponentially over the past 15 years.

Based on simulations conducted by Socas-Navarro, humanity will reach the threshold where its satellite band will be detectable by ETIs by 2200. Knowing that humanity will reach this threshold in the not-too-distant future makes the Clarke Belt a viable option for SETI. As Socas-Navarro explained:

“In this sense, the Clarke Exobelt is interesting because it’s the first technomarker that looks for currently existing technology. And it goes both ways too. Humanity’s Clarke Belt is probably too sparsely populated to be detectable from other stars right now (at least with technology like ours). But in the last decades we have been populating it at an exponential rate. If this trend were to continue, our Clarke Belt would be detectable from other stars by the year 2200. Do we want to be detectable? This is an interesting debate that humanity will have to resolve soon.




An exoplanet transiting across the face of its star, demonstrating one of the methods used to find planets beyond our solar system. Credit: ESA/C. Carreau
As for when we might be able to start looking for Exobelts, Socas-Navarro indicates that this will be possible within the next decade. Using instruments like the James Webb Space Telescope (JWST), the Giant Magellan Telescope (GMT), the European Extremely Large Telescope (E-ELT), and the Thirty Meter Telescope (TMT), scientists will have ground-based and space-based telescopes with the necessary resolution to spot these bands around exoplanets.

As for how these belts would be detected, that would come down to the most popular and effective means for finding exoplanets to date – the Transit Method (aka. Transit Photometry). For this method, astronomers monitor distant stars for periodic dips in brightness, which are indications of an exoplanet passing in front of the star. Using next-generation telescopes, astronomers may also be able to detect reflected light from a dense band of satellites in orbit.

“However, before we point our supertelescopes to a planet we need to identify good candidates,” said Socas-Navarro. “There are too many stars to check and we can’t go one by one. We need to rely on exoplanet search projects, such as the recently launched satellite TESS, to spot interesting candidates. Then we can do follow-up observations with supertelescopes to confirm or refute those candidates.”

In this respect, telescopes like the Kepler Space Telescope and the Transiting Exoplanet Survey Telescope (TESS) will still serve an important function in searching for technomarkers. Whereas the former telescope is due to retire soon, the latter is scheduled to launch in 2018.





Artist’s impression of an extra-solar planet transiting its star. Credit: QUB Astrophysics Research Center
While these space-telescopes would search for rocky planets that are located within the habitable zones of thousands of stars, next-generation telescopes could search for signs of Clarke Exobelts and other technomarkers that would be otherwise hard to spot. However, as Socas-Navarro indicated, astronomers could also find evidence of Exobands by sifting through existing data as well.

“In doing SETI, we have no idea what we are looking for because we don’t know what the aliens are doing,” he said. “So we have to investigate all the possibilities that we can think of. Looking for Clarke Exobelts is a new way of searching, it seems at least reasonably plausible and, most importantly, it’s free. We can look for signatures of Clarke Exobelts in currently existing missions that search for exoplanets, exorings or exomoons. We don’t need to build costly new telescopes or satellites. We simply need to keep our eyes open to see if we can spot the signatures presented in the simulation in the flow of data from all of those projects.”

Humanity has been actively searching for signs of extra-terrestrial intelligence for decades. To know that our technology and methods are becoming more refined, and that more sophisticated searches could begin within a decade, is certainly encouraging. Knowing that we won’t be visible to any ETIs that are out there for another two centuries, that’s also encouraging!

And be sure to check out this cool video by our friend, Jean Michael Godier, where he explains the concept of a Clarke Exobelt:



Further Reading: IAC, The Astrophysical Journal

The post One Way to Find Aliens Would be to Search for Artificial Rings of Satellites: Clarke Belts appeared first on Universe Today.

Saturday, June 2, 2018

Meteors, Planes, and a Galaxy over Bryce Canyon

Meteors, Planes, and a Galaxy over Bryce Canyon:

Discover the cosmos!
Each day a different image or photograph of our fascinating universe is
featured, along with a brief explanation written by a professional astronomer.


2018 May 6




See Explanation.  Clicking on the picture will download the highest resolution version available.


Meteors, Planes, and a Galaxy over Bryce Canyon

Image Credit & Copyright:
Dave Lane


Explanation:
Sometimes land and sky are both busy and beautiful.

The landscape pictured in the foreground encompasses
Bryce Canyon in
Utah,
USA, famous for its many interesting
rock structures eroded over millions of years.

The featured skyscape, photogenic in its own right, encompasses the
arching central disk of our
Milky Way Galaxy, the
short streaks of three passing planes near the horizon,
at least four long streaks that are likely
Eta Aquariid meteors,
and many stars including the three bright stars that make up the
Summer Triangle.

The
featured image
is a digital panorama created from 12 smaller images during this date in 2014.

Recurring every year, yesterday and tonight mark the peak of
this year's Eta Aquriids meteor shower, where a
patient observer with dark skies and
dark-adapted eyes might expect to see a
meteor every few minutes.




Tomorrow's picture: unusually placed rock




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Authors & editors:
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Jerry Bonnell (UMCP)
NASA Official: Phillip Newman
Specific rights apply.
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Spiral Galaxy NGC 4038 in Collision

Spiral Galaxy NGC 4038 in Collision:

Discover the cosmos!
Each day a different image or photograph of our fascinating universe is
featured, along with a brief explanation written by a professional astronomer.


2018 May 23




See Explanation.  Clicking on the picture will download the highest resolution version available.


Spiral Galaxy NGC 4038 in Collision

Image Credit:
NASA,
ESA,
Hubble,
HLA;
Processing & Copyright:
Domingo Pestana



Explanation:

This galaxy is having a bad millennium.

In fact, the past 100 million years haven't been so good,
and probably the next billion or so will be quite tumultuous.

Visible toward the lower right, NGC 4038 used to be a normal spiral galaxy, minding its own business, until NGC 4039, to its upper left,
crashed into it.

The evolving wreckage, known famously as
the Antennae, is featured here.

As gravity restructures each galaxy, clouds of gas slam into each other,
bright blue knots of stars form, massive stars form and
explode,
and brown filaments of dust are strewn about.

Eventually the
two galaxies
will converge into one larger spiral galaxy.

Such collisions are not unusual, and even our own
Milky Way Galaxy
has undergone several in the past and is
predicted to collide
with our neighboring
Andromeda Galaxy in a few billion years.

The
frames that compose this image were taken by the orbiting
Hubble Space Telescope by professional astronomers to
better understand galaxy collisions.

These frames -- and many other deep space images from
Hubble -- have since been
made public,
allowing interested amateurs to download and
process them into, for example, this visually stunning composite.



Tomorrow's picture: The Expanse




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NASA Official: Phillip Newman
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NASA Web
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GSFC

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Galaxies Away

Galaxies Away:

Discover the cosmos!
Each day a different image or photograph of our fascinating universe is
featured, along with a brief explanation written by a professional astronomer.


2018 May 25




See Explanation.  Clicking on the picture will download the highest resolution version available.


Galaxies Away

Image Credit &
Copyright:


Data -
Hubble Legacy Archive,

Processing -
Domingo Pestana



Explanation:

This stunning group of galaxies is far, far away,
about 450 million light-years from
planet Earth
and cataloged as galaxy cluster Abell S0740.

Dominated by the cluster's large central elliptical galaxy
(ESO 325-G004), this reprocessed
Hubble
Space Telescope view
takes in a
remarkable assortment of galaxy shapes and sizes with
only a few spiky foreground stars
scattered through the field.

The giant elliptical galaxy
(right of center)
spans over 100,000 light years and
contains about 100 billion stars, comparable in
size to our own spiral Milky Way galaxy.

The Hubble data can reveal a
wealth
of detail
in even these distant galaxies, including
arms and dust lanes, star clusters, ring structures,
and gravitational lensing arcs.



Tomorrow's picture: Moon over Saturn




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Two Spacecraft Will Get Closer to the Sun Than Ever Before

Two Spacecraft Will Get Closer to the Sun Than Ever Before:

Our understanding of distant stars has increased dramatically in recent decades. Thanks to improved instruments, scientists are able to see farther and clearer, thus learning more about star systems and the planets that orbit them (aka. extra-solar planets). Unfortunately, it will be some time before we develop the necessary technology to explore these stars up close.

But in the meantime, NASA and the ESA are developing missions that will allow us to explore our own Sun like never before. These missions, NASA’s Parker Solar Probe and the ESA’s (the European Space Agency) Solar Orbiter, will explore closer to the Sun than any previous mission. In so doing, it is hoped that they will resolve decades-old questions about the inner workings of the Sun.

These missions – which will launch in 2018 and 2020, respectively – will also have significant implications for life here on Earth. Not only is sunlight essential to life as we know it, solar flares can pose a major hazard for technology that humanity is becoming increasingly dependent on. This includes radio communications, satellites, power grids and human spaceflight.



And in the coming decades, Low-Earth Orbit (LEO) is expected to become increasingly crowded as commercial space stations and even space tourism become a reality. By improving our understanding of the processes that drive solar flares, we will therefore be able to better predict when they will occur and how they will impact Earth, spacecraft, and infrastructure in LEO.

As Chris St. Cyr, the Solar Orbiter project scientist at NASA’s Goddard Space Flight Center, explained in a recent NASA press release:

“Our goal is to understand how the Sun works and how it affects the space environment to the point of predictability. This is really a curiosity-driven science.”
Both missions will focus on the Sun’s dynamic outer atmosphere, otherwise known as the corona. At present, much of the behavior of this layer of the Sun is unpredictable and not well understood. For instance, there’s the so-called “coronal heating problem”, where the corona of the Sun is so much hotter than the solar surface. Then there is the question of what drives the constant outpouring of solar material (aka. solar wind) to such high speeds.

As Eric Christian, a research scientist on the Parker Solar Probe mission at NASA Goddard, explained:

“Parker Solar Probe and Solar Orbiter employ different sorts of technology, but — as missions — they’ll be complementary. They’ll be taking pictures of the Sun’s corona at the same time, and they’ll be seeing some of the same structures — what’s happening at the poles of the Sun and what those same structures look like at the equator.”




Illustration of the Parker Solar Probe spacecraft approaching the Sun. Credits: Johns Hopkins University Applied Physics Laboratory
For its mission, the Parker Solar Probe will get closer to the Sun than any spacecraft in history – as close as 6 million km (3.8 million mi) from the surface. This will replace the previous record of 43.432 million km (~27 million mi), which was established by the Helios B probe in 1976. From this position, the Parker Solar Probe will use its four suites of scientific instruments to image the solar wind and study the Sun’s magnetic fields, plasma and energetic particles.

In so doing, the probe will help clarify the true anatomy of the Sun’s outer atmosphere, which will help us to understand why the corona is hotter than the Sun’s surface. Basically, while temperatures in the corona can reach as high as a few million degrees, the solar surface (aka. photosphere), experiences temperatures of around 5538 °C (10,000 °F).

Meanwhile, the Solar Orbiter will come to a distance of about 42 million km (26 million mi) from the Sun, and will assume a highly-tilted orbit that can provide the first-ever direct images of the Sun’s poles. This is another area of the Sun that scientists don’t yet understand very well, and the study of it could provide valuable clues as to what drives the Sun’s constant activity and eruptions.

Both missions will also study solar wind, which is the Sun’s most pervasive influence on the solar system. This steam of magnetized gas fills the inner Solar System, interacting with magnetic fields, atmospheres and even the surfaces of planets. Here on Earth, it is what is responsible for the Aurora Borealis and Australis, and can also play havoc with satellites and electrical systems at times.





Artist’s impression of a solar flare erupting from the Sun’s surface. Credit: NASA Goddard Space Flight Center
Previous missions have led scientists to believe that the corona contributes to the process that accelerates solar wind to such high speeds. As these charged particles leave the Sun and pass through the corona, their speed effectively triples. By the time the solar wind reaches the spacecraft responsible for measuring it – 148 million km (92 million mi) from the Sun – it has plenty of time to mix with other particles from space and lose some of its defining features.

By being parked so close to the Sun, the Parker Solar Probe will able to measure the solar wind just as it forms and leaves the corona, thus providing the most accurate measurements of solar wind ever recorded. From its perspective above the Sun’s poles, the Solar Orbiter will complement the Parker Solar Probe’s study of the solar wind by seeing how the structure and behavior of solar wind varies at different latitudes.

This unique orbit will also allow the Solar Orbiter to study the Sun’s magnetic fields, since some of the Sun’s most interesting magnetic activity is concentrated at the poles. This magnetic field is far-reaching largely because of solar wind, which reaches outwards to create a magnetic bubble known as the heliosphere. Within the heliosphere, solar wind has a profound effect on planetary atmospheres and its presence protects the inner planets from galactic radiation.

In spite of this, it is still not entirely clear how the Sun’s magnetic field is generated or structured deep inside the Sun. But given its position, the Solar Orbiter will be able to study phenomena that could lead to a better understanding of how the Sun’s magnetic field is generated. These include solar flares and coronal mass ejections, which are due to variability caused by the magnetic fields around the poles.



In this way, the Parker Solar Probe and Solar Orbiter are complimentary missions, studying the Sun from different vantage points to help refine our knowledge of the Sun and heliosphere. In the process, they will provide valuable data that could help scientists to tackle long-standing questions about our Sun. This could help expand our knowledge of other star systems and perhaps even answer questions about the origins of life.

As Adam Szabo, a mission scientist for Parker Solar Probe at NASA Goddard, explained:

“There are questions that have been bugging us for a long time. We are trying to decipher what happens near the Sun, and the obvious solution is to just go there. We cannot wait — not just me, but the whole community.”
In time, and with the development of the necessary advanced materials, we might even be able to send probes into the Sun. But until that time, these missions represent the most ambitious and daring efforts to study the Sun to date. As with many other bold initiatives to study our Solar System, their arrival cannot come soon enough!

Further Reading: NASA

The post Two Spacecraft Will Get Closer to the Sun Than Ever Before appeared first on Universe Today.