Atmospheric temperatures on Jupiter range from around 1,700 degrees Fahrenheit to upward of 2,420 degrees. That's greater than the temperature of molten lava and would cause lithium batteries in cellphones to boil and turn to gas. These wide ranges in temperature could not just be explained by heat from the sun, said James O'Donoghue, a research scientist at Boston University's Center for Space Physics.
Researchers from Boston University's (BU) Center for Space Physics report today in Nature that Jupiter's Great Red Spot may provide the mysterious source of energy required to heat the planet's upper atmosphere to the unusually high values observed.
Sunlight reaching Earth efficiently heats the terrestrial atmosphere at altitudes well above the surfaceeven at 250 miles high, for example, where the International Space Station orbits. Jupiter is over five times more distant from the Sun, and yet its upper atmosphere has temperatures, on average, comparable to those found at Earth. The sources of the non-solar energy responsible for this extra heating have remained elusive to scientists studying processes in the outer solar system.
“With solar heating from above ruled out, we designed observations to map the heat distribution over the entire planet in search for any temperature anomalies that might yield clues as to where the energy is coming from,” explained Dr. James O'Donoghue, research scientist at BU, and lead author of the study.
Astronomers measure the temperature of a planet by observing the non-visible, infrared (IR) light it emits. The visible cloud tops we see at Jupiter are about 30 miles above its rim; the IR emissions used by the BU team came from heights about 500 miles higher. When the BU observers looked at their results, they found high altitude temperatures much larger than anticipated whenever their telescope looked at certain latitudes and longitudes in the planet's southern hemi-sphere.
Jupiter's Great Red Spot (GRS) is one of the marvels of our solar system. Discovered within years of Galileo's introduction of telescopic astronomy in the 17th Century, its swirling pattern of colorful gases is often called a “perpetual hurricane.” The GRS has varied is size and color over the centuries, spans a distance equal to three earth-diameters, and has winds that take six days to complete one spin. Jupiter itself spins very quickly, completing one revolution in only ten hours.
“The Great Red Spot is a terrific source of energy to heat the upper atmosphere at Jupiter, but we had no prior evidence of its actual effects upon observed temperatures at high altitudes,” ex-plained Dr. Luke Moore, a study co-author and research scientist in the Center for Space Physics at BU.
Solving an “energy crisis” on a distant planet has implications within our solar system, as well as for planets orbiting other stars. As the BU scientists point out, the unusually high temperatures far above Jupiter's visible disk is not a unique aspect of our solar system. The dilemma also occurs at Saturn, Uranus and Neptune, and probably for all giant exoplanets outside our solar system.
“Energy transfer to the upper atmosphere from below has been simulated for planetary atmospheres, but not yet backed up by observations,” O'Donoghue said. “The extremely high temperatures observed above the storm appear to be the ‘smoking gun' of this energy transfer, indicating that planet-wide heating is a plausible explanation for the ‘energy crisis.'”
The Daily Galaxy via Boston University
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Located approximately 22 000 light-years away in the constellation of Musca (The Fly), this tightly packed collection of stars - known as a globular cluster - goes by the name of NGC 4833. This NASA/ESA Hubble Space Telescope image shows the dazzling stellar group in all its glory.
NGC 4833 is one of the over 150 globular clusters known to reside within the Milky Way. These objects are thought to contain some of the oldest stars in our galaxy. Studying these ancient cosmic clusters can help astronomers to unravel how a galaxy formed and evolved, and give an idea of the galaxyâs age.
Globular clusters are responsible for some of the most striking sights in the cosmos, with hundreds of thousands of stars congregating in the same region of space. Hubble has observed many of these clusters during its time in orbit around our planet, each as breathtaking as the last.
Credit: ESA/Hubble and NASA
In the first few minutes following “the big bang,” the universe quickly began expanding and cooling, allowing the formation of subatomic particles that joined forces to become protons and neutrons. These particles then began interacting with one another to create the first simple atoms. A little more time, a little more expansion, a lot more cooling—along with ever-present gravitational pull—and clouds of these elements began to morph into stars and galaxies.
For William Detmold, an assistant professor of physics at MIT who uses lattice quantum chromodynamics (LQCD) to study subatomic particles, one of the most interesting aspects of the formation of the early universe is what happened in those first few minutes—a period known as the “big bang nucleosynthesis.”
“You start off with very high-energy particles that cool down as the universe expands, and eventually you are left with a soup of quarks and gluons, which are strongly interacting particles, and they form into protons and neutrons,” he said. “Once you have protons and neutrons, the next stage is for those protons and neutrons to come together and start making more complicated things—primarily deuterons, which interact with other neutrons and protons and start forming heavier elements, such as Helium-4, the alpha particle.”
One of the most critical aspects of big bang nucleosynthesis is the radiative capture process, in which a proton captures a neutron and fuses to produce a deuteron and a photon. In a paper published in Physical Review Letters, Detmold and his co-authors—all members of the NPLQCD Collaboration, which studies the properties, structures and interactions of fundamental particles—describe how they used LQCD calculations to better understand this process and precisely measure the nuclear reaction rate that occurs when a neutron and proton form a deuteron. While physicists have been able to experimentally measure these phenomena in the laboratory, they haven't been able to do the same, with certainty, using calculations alone—until now.
“One of the things that is very interesting about the strong interaction that takes place in the radiative capture process is that you get very complicated structures forming, not just protons and neutrons,” Detmold said. “The strong interaction has this ability to have these very different structures coming out of it, and if these primordial reactions didn't happen the way they happened, we wouldn't have formed enough deuterium to form enough helium that then goes ahead and forms carbon. And if we don't have carbon, we don't have life.”
For the Physical Review Letters paper, the team used the Chroma LQCD code developed at Jefferson Lab to run a series of calculations with quark masses that were 10-20 times the physical value of those masses. Using heavier values rather than the actual physical values reduced the cost of the calculations tremendously, Detmold noted. They then used their understanding of how the calculations should depend on mass to get to the physical value of the quark mass.
“When we do an LQCD calculation, we have to tell the computer what the masses of the quarks we want to work with are, and if we use the values that the quark masses have in nature it is very computationally expensive,” he explained. “For simple things like calculating the mass of the proton, we just put in the physical values of the quark masses and go from there. But this reaction is much more complicated, so we can't currently do the entire thing using the actual physical values of the quark masses.
While this is the first LQCD calculation of an inelastic nuclear reaction, Detmold is particularly excited by the fact that being able to reproduce this process through calculations means researchers can now calculate other things that are similar but that haven't been measured as precisely experimentally—such as the proton-proton fusion process that powers the sun—or measured at all.
“The rate of the radiative capture reaction, which is really what we are calculating here, is very, very close to the experimentally measured one, which shows that we actually understand pretty well how to do this calculation, and we've now done it, and it is consistent with what is experimentally known,” Detmold said. “This opens up a whole range of possibilities for other nuclear interactions that we can try and calculate where we don't know what the answer is because we haven't, or can't, measure them experimentally. Until this calculation, I think it is fair to say that most people were wary of thinking you could go from quark and gluon degrees of freedom to doing nuclear reactions. This research demonstrates that yes, we can.”
The Daily Galaxy via https://www.nersc.gov/news
"There is a powerful analogy between the Earth's first mass extinction and what is happening today," said Simon Darroch, at Vanderbilt University. "The end-Ediacaran extinction shows that the evolution of new behaviors can fundamentally change the entire planet, and today we humans are the most powerful 'ecosystems engineers' ever known."
Newly discovered fossil evidence from Namibia strengthens the proposition that the world's first mass extinction was caused by "ecosystem engineers" - newly evolved biological organisms that altered the environment so radically it drove older species to extinction. The event, known as the end-Ediacaran extinction, took place 540 million years ago. The earliest life on Earth consisted of microbes - various types of single-celled organisms. These held sway for more than 3 billion years, when the first multicellular organisms evolved. The most successful of these were the Ediacarans, which spread around the globe about 600 million years ago. They were a largely immobile form of marine life shaped like discs and tubes, fronds and quilted mattresses.
After 60 million years, evolution gave birth to another major innovation: metazoans, the first animals. Metazoans could move spontaneously and independently at least during some point in their life cycle and sustain themselves by eating other organisms or what other organisms produce. Animals burst onto the scene in a frenzy of diversification that paleontologists have labeled the Cambrian explosion, a 25 million-year period when most of the modern animal families - vertebrates, mollusks, arthropods, annelids, sponges and jellyfish - came into being.
"These new species were 'ecological engineers' who changed the environment in ways that made it more and more difficult for the Ediacarans to survive," said Darroch, assistant professor of earth and environmental sciences, who directed the new study.
Darroch and his colleagues report that they have found one of the best-preserved examples of a mixed community of Ediacarans and animals, which provides the best evidence of a close ecological association between the two groups.
"Until this, the evidence for an overlapping ecological association between metazoans and soft-bodied Ediacaran organisms was limited," Darroch said. "Here, we describe new fossil localities from southern Namibia that preserve soft-bodied Ediacara biota, enigmatic tubular organisms thought to represent metazoans and vertically oriented metazoan trace fossils. Although the precise identity of the tracemakers remains elusive, the structures bear several striking similarities with a cone-shaped organism called Conichnus that has been found in the Cambrian period."
In a previous paper that Darroch and his collaborators published last September, they reported on a fossil record that showed stressed-looking communities of Ediacara associated with a suite of animal burrows.
"With this paper we're narrowing in on causation; we've discovered some new fossil sites that preserve both Ediacara biota and animal fossils (both animal burrows - 'trace fossils' - and the remains of animals themselves) sharing the same communities, which lets us speculate about how these two very different groups of organisms interacted," he said.
Conichnus burrows are trace fossils: the surface bumps shown below represent vertical tubes that were originally occupied by anemone-like animals that may have fed on Ediacaran larvae.
"Some of the burrow fossils we've found are usually interpreted as being formed by sea anemones, which are passive predators that may have preyed upon Ediacaran larvae. We've also found stands of Ediacaran frondose organisms, with animal fossils preserved in place coiled around their bases. In general, these new fossil sites reveal a snapshot of a very unusual 'transitional' ecosystem existing right before the Cambrian explosion, with the last of the Ediacara biota clinging on for grim death, just as modern-looking animals are diversifying and starting to realize their potential."
The Daily Galaxy via Vanderbilt University
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Russian poster for FOUR ADVENTURES OF REINETTE AND MIRABELLE (Eric Rohmer, France, 1987)
Artist: unknown
Poster source: Una Pagina de Cine
This artist's conception shows a red dwarf star orbited by a pair of habitable planets. Because red dwarf stars live so long, the probability of cosmic life grows over time. As a result, Earthly life might be considered “premature.” (Image by Christine Pulliam/CfA)
The universe is 13.8 billion years old, while our planet formed just 4.5 billion years ago. Some scientists think this time gap means that life on other planets could be billions of years older than ours. However, new theoretical work suggests that present-day life is actually premature from a cosmic perspective.
“If you ask, ‘When is life most likely to emerge?' you might naively say, ‘Now,'” says lead author Avi Loeb of the Harvard-Smithsonian Center for Astrophysics. “But we find that the chance of life grows much higher in the distant future.”
Life as we know it first became possible about 30 million years after the Big Bang, when the first stars seeded the cosmos with the necessary elements like carbon and oxygen. Life will end 10 trillion years from now when the last stars fade away and die. Loeb and his colleagues considered the relative likelihood of life between those two boundaries.
The dominant factor proved to be the lifetimes of stars. The higher a star's mass, the shorter its lifetime. Stars larger than about three times the sun?s mass will expire before life has a chance to evolve.
Conversely, the smallest stars weigh less than 10 percent as much as the Sun. They will glow for 10 trillion years, giving life ample time to emerge on any planets they host. As a result, the probability of life grows over time. In fact, chances of life are 1000 times higher in the distant future than now.
“So then you may ask, why aren't we living in the future next to a low-mass star?” says Loeb.
“One possibility is we're premature. Another possibility is that the environment around a low-mass star is hazardous to life.”
Although low-mass, red dwarf stars live for a long time, they also pose unique threats. In their youth they emit strong flares and ultraviolet radiation that could strip the atmosphere from any rocky world in the habitable zone.
To determine which possibility is correct — our premature existence or the hazard of low-mass stars — Loeb recommends studying nearby red dwarf stars and their planets for signs of habitability. Future space missions like the Transiting Exoplanet Survey Satellite and James Webb Space Telescope should help to answer these questions.
The paper describing this work has been accepted for publication in the Journal of Cosmology and Astroparticle Physics and is available online. Its co-authors are Avi Loeb (Harvard-Smithsonian Center for Astrophysics) and Rafael Batista and David Sloan (University of Oxford). Loeb simultaneously wrote an extended review on the habitability of the universe as a chapter for a forthcoming book.
The post IS EARTHLY LIFE PREMATURE FROM A COSMIC PERSPECTIVE? appeared first on Smithsonian Insider.
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Johann Jakob Scheuchzer Scientist of the Day
Johann Jakob Scheuchzer, a Swiss paleontologist and geologist, was born Aug. 2, 1672.
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The splash story on one Sunday newspaper breezily informed us Brits used six billion fewer plastic bags this year than last, and that these weighed the same as “three million pelicans” a grave naughtiness committed before El Reg's Standards Soviet.…