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Author Topic: NEWS ON SPACE AND OUR PLANETARY SYSTEM  (Read 388976 times)
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Darja
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« Reply #1725 on: Jul 06, 2018, 04:29 AM »

Rumors of Opportunity’s death “very premature”, despite three-weeks silence

Alexandru Micu
ZME
7/6/2018

NASA’s last contact with the Opportunity Rover took place over three weeks ago. Despite this, the agency believes it’s too early to assume the worst case scenario — the rover’s demise.

We’ve been talking a lot about the huge dust storm that’s engulfed Mars of late, and of how NASA’s two rovers — Opportunity and Curiosity — are weathering the event. Out of the two, Curiosity has been served the much sweeter side of the dish: powered by a nuclear reactor and sitting out of the storm’s way, it’s been free to leisurely capture pics of the weather (and itself).

The older and solar-powered Opportunity, however, is stuck in the massive storm. Besides getting pelted by dust that may harm its scientific instruments, the rover is also unable to recharge. Dust blocks so much of the incoming sunlight that Opportunity’s solar panels just can’t create a spark. Bereft of battery charge, the rover stands a real chance of freezing to death on — fittingly– Mars’ Perseverance Valley.
Tough as old (ro)boots

Opportunity has been on duty for some 14 years now. It’s a veteran space explorer that relayed treasure troves of data for researchers back here on Earth. I’m rooting for the bot to weather the storm. By this point, however, it’s been three weeks since it last established contact with NASA — enough to make even the most resolute worry about its fate.

Dr. James Rice, co-investigator and geology team leader on NASA projects including Opportunity, says we shouldn’t assume the worst just yet.

Talking with Space Insider, Dr. Rice explains during its last contact with NASA, Opportunity also sent back a power reading. It showed the rover managed to scrape a meager 22 Wh of energy from its solar panels. For context, the rover managed to collect 645 Wh of energy from its panels just ten days before. This chokehold on energy is the NASA’s main concern at the moment.

However, he adds that the same storm which prevents Opportunity from recharging its batteries may ultimately also be its salvation.

One of the reasons NASA was caught offguard by the storm is that they simply don’t generally form around this time of the Martian Year. It’s currently spring on the Red Planet’s Southern Hemisphere, but dust storms usually form during summer. The only other dust event NASA recorded during the Martian Spring formed in 2001, and even that one came significantly later in the season than the current storm.
Mars storm.

The first indications of a dust storm appeared back on May 30. The team was notified, and put together a 3-day plan to get the rover through the weekend. After the weekend the storm was still going, with atmospheric opacity jumping dramatically from day to day.

Still, at least it’s not winter — so average temperatures aren’t that low on Mars right now. The dust further helps keep Opportunity warmer, as it traps heat around the rover.

    “We went from generating a healthy 645 watt-hours on June 1 to an unheard of, life-threatening, low just about one week later. Our last power reading on June 10 was only 22 watt hours the lowest we have ever seen” Dr. Rice explained.

    “Our thermal experts think that we will stay above those low critical temperatures because we have a Warm Electronics Box (WEB) that is well insulated. So we are not expecting any thermal damage to the batteries or computer systems. Fortunately for us it is also the Martian Spring and the dust, while hindering our solar power in the day, helps keep us warmer at night,” he added.

The storm has reached 15.8 million square miles (41 million square kilometers) in size this June. It poses a real risk to Opportunity’s wellbeing, but ground control remains optimistic. Mars Exploration Program director Jim Watzin believes that the massive storm may have already peaked — but, considering that it took roughly a month for it to build up, it could take a “substantial” amount of time before it dissipates completely.

    “As of our latest Opportunity status report Saturday (June 30) this storm shows no sign of abating anytime soon. We had a chance to conduct an uplink last night at the potential low-power fault window. We sent a real-time activate of a beep as we have done over the past two weeks. We had a negative detection of the beep at the expected time,” Dr Rice added.

    “A formal listening strategy is in development for the next several months.”

Among all this, or rather also because of all that’s happening to Opportunity, I can’t help but feel genuine admiration for it as well as the people who helped put it together. Opportunity was first launched in 2004 and along its sister craft Spirit, was supposed to perform a 90-day mission. Spirit kept going until 2010, and Opportunity is still going strong today (and hopefully for longer). That’s a level of dedication I can only dream of.

Based in part on the rover’s rugged track record, Dr. Rice believes that “rumors of Opportunity’s death are very premature at this point.”


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« Reply #1726 on: Jul 07, 2018, 04:56 AM »

Most objects in the asteroid belt come from a handful of wrecked ancient planets

ZME
7/7/2018

Most people think of asteroids as scary, cold, and lifeless blobs of rock hurtling around the solar system. That’s a pretty accurate description, but that doesn’t mean that asteroids don’t get to have families. According to a new study, 85% of all objects in the asteroid belt can trace their origin to five or six planetoids (small planets) that turned to smithereens in the early days of the solar system. Accordingly, there are five to six families of asteroids tracing their lineage back to these larger parent bodies.
Illustration of an asteroid belt. Credit: NASA.

About four to five billion years ago, the solar system was a chaotic, crowded mess. Many of today’s planets had yet to form in their current configuration and collisions between massive planetary bodies were quite routine. Eventually, all this colliding gave rise to many of the solar system’s moons and to the countless asteroids that litter the outskirts of the system. For instance, the main asteroid belt — located between the orbits of Mars and Jupiter — is estimated to contain millions of objects, although only hundreds of thousands have actually been observed.

While these parent bodies fragmented into thousands of smaller bits and pieces, it is possible to piece them back together based on their trajectories. In 1918, Japanese astronomer Kiyotsugu Hirayama was the first to notice that asteroids had similar elements, such as eccentricity and inclination, to their orbit. Suddenly, asteroids were no longer randomly zipping through the solar system but rather groups sharing orbital elements.

Based on Hirayama’s ideas, for the past 100 years, astronomers have grouped asteroids into families and non-families, with only half of all the asteroids that we know of being classed in families. However, this division into families and non-families is not productive, according to researchers led by Stanly Dermott, a Professor of Astronomy at the University of Florida.

Dermott and colleagues found that there’s a relationship between the orbital elements of asteroids and their sizes. By analyzing the dimensions of asteroids and their distribution within the inner asteroid belt, the team was able to classify 85% of the asteroid into about six families, each named after the biggest object in the family. They are Vesta, Flora, Nysa, Polana, Eulalia, and Hungaria. In 2011, NASA’s Dawn spacecraft visited Vesta.

    “I wouldn’t be surprised if we eventually trace the origins of all asteroids in the main asteroid belt, not just those in the inner belt, to a small number of known parent bodies,” Dermott said.

The other 15 percent may also trace their origins to the same group of primordial bodies. What astronomers had previously thought of as ‘non-family’ asteroids were likely part of one of the six families, as well — just that they had become estranged due to the gravitational pull of Jupiter or Saturn, which changed their orbits ever so slightly.

The team only analyzed 200,000 asteroids, all found in the inner asteroid belt, which is closer to Earth and more studied than the middle or outer asteroid belt. A NASA survey tracked over 780,000 asteroids in the belt as a whole. This means there’s a lot of room to learn about asteroids. Perhaps there are more families, for instance. What’s more, there’s a similar ongoing analysis, only this time of meteorites, which are the bits of asteroids that survive atmospheric entry and reach Earth. This kind of information could prove essential to protecting the Earth and ourselves from killer asteroids of the kind that wiped out the dinosaurs.

     “These large bodies whiz by the Earth, so of course we’re very concerned about how many of these there are and what types of material are in them,” Dermott said. “If ever one of these comes towards the Earth, and we want to deflect it, we need to know what its nature is.”


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« Reply #1727 on: Jul 09, 2018, 04:35 AM »

Comet 67P harbors oxygen molecules as old as the Solar System

ZME
7/9/2018

Molecular oxygen found on the comet 67P/Churyumov-Gerasimenko isn’t produced on the surface — it comes from the early days of the Solar System.

Between August 2014 and September 2016, the European Space (ESA) Agency’s Rosetta craft tagged along with the comet  67P/Churyumov-Gerasimenko as it was trekking around the Sun. The mission also saw a probe delivered to the comet’s surface.

Among other things, the ESA wanted to use Rosetta to study the comet’s coma — the nebulous envelope around the nucleus of a comet. This structure is created by ice subliming — turning from a solid directly into a gas — on the comet’s surface under the sun’s rays. Rosetta’s analysis of the coma revealed that it contains water, carbon monoxide and dioxide (all compounds we were expecting to find), but also molecular oxygen.

Retro oxygen

Molecular oxygen is composed of two oxygen atoms tied together by a covalent bond. Here on Earth, it’s produced by plants via photosynthesis, but researchers are well aware that oxygen is abundant in many places of the universe — we’ve detected molecular oxygen around some of Jupiter’s moons, for example. By mass, oxygen is the third-most abundant element in the universe, after hydrogen and helium — but finding it around a comet was surprising, to say the least.

With the finding also came questions regarding the origin of this molecular oxygen. Some researchers suggested that it might be produced on the comet’s surface under the action of charged ions in the solar wind.

A new paper published by members of the Rosetta team has analyzed data beamed back by the craft to get to the bottom of the issue. The research, led by researchers from the Imperial College London, found that the proposed ionic mechanism for molecular oxygen generation couldn’t account for levels of this molecule observed in the coma. This would mean that the oxygen molecules Rosetta stumbled upon are primordial — meaning they were already fully formed as the comet itself quickened during the early days of the Solar System 4.6 billion years ago.

    “We tested the new theory of surface molecular oxygen production using observations of energetic ions, particles which trigger the surface processes which could lead to the production of molecular oxygen,” said lead author Mr Kevin Heritier. “We found that the amount of energetic ions present could not produce enough molecular oxygen to account for the amount of molecular oxygen observed in the coma.”

The findings don’t rule out oxygen generation at the surface level of 67P — but that the majority of the oxygen in the comet’s coma is simply not produced through such a process.

While there are other theories regarding the origin of 67P’s oxygen, the team didn’t address them in any way, either to confirm or infirm them. So far, however, they say that the primordial oxygen theory is the one which fits available data best. This is further supported by other theoretical work that treats the formation of molecular oxygen in dark clouds and the presence of molecular oxygen in the early Solar System, they add. In the team’s model, preexisting molecular oxygen froze into tiny grains that later clumped together, attracted more material, and eventually got bound up in the comet’s nucleus.

The paper “On the origin of molecular oxygen in cometary comae” has been published in the journal Nature Communications.


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« Reply #1728 on: Jul 10, 2018, 04:47 AM »

Scientists collect interstellar dust that formed the Earth and solar system

ZME
7/10/2018

Researchers have discovered an enormous body of interstellar dust that predates the formation of our solar system 4.6 billion years ago. The findings might revolutionize our understanding of how the solar system came to be, as well as all other planetary bodies.

It sounds unbelievable, but some of the original interstellar dust that went to form the sun, Earth, and all the other planets in the solar system can be still be found floating around in our neighborhood, even hitting our atmosphere from time to time. Presolar dust particles can no longer be found in the inner solar system, as it was long ago destroyed, reformed, and reaggregated in multiple phases. However, presolar dust can still be found in the outer solar system, specifically in some comets.

When these comets pass close enough to the sun, they release presolar dust that can reach Earth’s orbit and settle through the atmosphere, where it can be collected and later studied. Dr. Hope Ishii of the University of Hawai’i at Manoa and her colleagues used electron microscopy to study such dust particles, as well as data gathered from the Cosmic Dust Analyzer (CDA) aboard the Cassini Saturn orbiter during its two-decade mission.

The presolar dust particles in question are actually called GEMS – or ‘glass embedded with metal and sulfide’. They’re less than one hundredth the width of a human hair in diameter and contain a variety of carbon known to decompose when exposed to even relatively gentle heating.

An electron micrograph of an interplanetary dust particle of likely cometary origin. Credit: Hope Ishii

Ishii and colleagues write that the GEMS likely formed in the interstellar medium due to grain shattering, amorphization, and erosion from supernovae shocks, then later went through subsequent periods of aggregation. Irradiation likely provided enough energy for the amorphous silicates which comprise the dust to absorb small amounts of metal atoms, the authors reported in the journal Proceedings of the National Academy of Sciences.

    “With repeated cycling in and out of cold molecular clouds, mantled dust and any aggregates were repeatedly and progressively partially destroyed and reformed. Cassini mission data suggest the presence of iron metal in contemporary interstellar dust,” the researchers wrote in their study.

This first generation of GEMS aggregated with crystalline grains that were likely transported from the hot inner-solar nebula, creating second-generation aggregates. Later this 2nd generation of aggregates was likely incorporated into small, icy cometary bodies.

The researchers concluded that the grains they studied represent surviving pre-solar interstellar dust that formed the very building blocks of planets and stars. As such, they provide unique insight into a pre-solar system environment, ultimately telling us how our planet and others like it came to be. We only have a rough picture of how our solar system formed from a huge disk of dust and gas, and these little grains could be the missing pieces that complete the puzzle. In the future, the researchers plan on collecting more comet dust, particularly that sourced from more well-protected comets that pass by the sun.

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« Reply #1729 on: Jul 11, 2018, 04:34 AM »

New Horizons wakes up for its most remote target yet — Ultima Thule

ZME
7/11/2018

NASA’s New Horizons awakens from its slumber in time for the farthest planetary encounter in history — a flyby of Ultima Thule.

The historic encounter is scheduled to take place on New Year’s Day in 2019. Since it wouldn’t do to sleep during such an important meeting, NASA woke the craft from its 165-day-long hibernation on June 4. This was the second period of inactivity for the craft, both of which were meant to conserve energy.  The craft will remain active through to late 2020 to beam back all the data from its contact with Ultima and the wider Kuiper Belt.

Not in Kansas anymore

The Kuiper Belt isn’t exactly a stone’s throw away — except maybe if that stone is a meteorite. It’s similar to the asteroid belt between Mars and Jupiter, only much more massive, and much farther away. The Kuiper Belt lies between 4.5 to 7.5 billion kilometers (2.8 to 4.6 billion miles) away from the Sun, roughly 20 to 50 times astronomical units (AUs), the distance between the Earth and our star.

New Horizons has already traveled an impressive stretch of this distance. It went past Pluto and is currently cruising through the belt properly, some 3.7 billion miles (6 billion kilometers) from Earth.

On June 4th, NASA ended the craft’s energy-saving hibernation mode, which was initiated last December. Ground control — situated at the Johns Hopkins Applied Physics Laboratory in Laurel, Maryland — received confirmation that onboard systems have resumed normal activity on June 5 2:12 a.m. local time, via NASA’s Deep Space Network. So far, everything seems in order and all systems are coming online without a hitch, the ream reports.

They will spend the next three days collecting navigation data from New Horizons and transmitting commands to prepare it for its Ultima flyby. It takes a lot of time to send a message that far into space, nearly 6 hours each way. The data traffic will include memory updates, subsystem and science-instrument diagnostics, as well as retrieval of information stored in New Horizon’s memory banks.

The whole process is estimated to take about two months, the team adds. On August 13th, the team will take the probe out of its stabilizing spin state. In mid- to late-August, they plan to instruct it to make distant observations of Ultima in order to refine its course towards the object. Its small size (about 20 to 23 miles in diameter) and the lack of light will make Ultima Thule hard to spot, but the team is anxious to try — this would be the first time any human has seen the object.

    “Our team is already deep into planning and simulations of our upcoming flyby of Ultima Thule and excited that New Horizons is now back in an active state to ready the bird for flyby operations, which will begin in late August,” said mission Principal Investigator Alan Stern.

New Horizons is roughly 262 million kilometers (162 million miles) from Ultima — a bit under two AUs — and is speeding towards its mysterious target at a speed of 1,223,420 kilometers (760,200 miles) per day. Which is a lot.


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« Reply #1730 on: Jul 12, 2018, 04:28 AM »

Cosmos Offers Clues to the Fate of Humans on Earth

By Marlene Cimons
Ecowatch
7/12/2018

Astrophysicist Adam Frank sees climate change through a cosmic lens. He believes our present civilization isn't the first to burn up its resources—and won't be the last. Moreover, he thinks it's possible the same burnout fate already might have befallen alien worlds. That's why he says the current conversation about climate change is all wrong. "We shouldn't be talking about saving the planet, because the Earth will go on without us," he said. "We should be talking about saving ourselves."

A professor of physics and astronomy at the University of Rochester, Frank says viewing climate change in the context of astrobiology—the study of life in a planetary framework—raises important new questions that could better define our destiny in a warming world. All civilizations increasingly deplete their assets as their populations grow, altering environmental conditions along the way. Climate change shouldn't come as a surprise to anyone, he said—it's the inevitable result of a civilization reveling in its own success.

"This is a big universe, and I don't know how long civilizations last," Frank said. "We're just one of them. Some of them almost certainly burned themselves out. Life has driven profound changes in climate a number of times in Earth's history, and we're the one that's happening now. We should have expected climate change knowing what we know about how climate change works. Any civilization will drive their planet into an Anthropocene," he said, referring to an age when human activities have a profound influence on climate and the Earth's ecosystems. "Knowing this changes entirely how we should frame climate change, and how we talk about it."

Watch: https://www.youtube.com/watch?v=uoISn18qP_E

First, the denial and finger-pointing must end, he said. "We have to stop the blaming and the human-hating, because the Earth will just move on, with or without us," he said. "We didn't trigger climate change on purpose. It was an accident. Any technological civilization that evolves on any planet cannot help but trigger climate change. Climate change is not our fault. Not doing something about it—that will be our fault."

If we accept that life on Earth as we now know it is an experiment of the biosphere, then allowing climate change to destroy us will only enable another experiment to take its place, he said. When all the dinosaurs died more than 65 million years ago, for example, other species evolved and moved in—including us. That's how the biosphere works.

"After the mass extinction of the dinosaurs, your ancestor mammals survived," Frank said. "Earth just filled all the niches. We're here because of it. The biosphere has run a lot of experiments, and we're just the latest. Humanity is what the biosphere is doing right now. If we don't make it, we become the agent for the next round of the biosphere's experiments. What we have to figure out is how to still be what the biosphere is doing thousands of years from now."

Frank and his collaborators—including Jonathan Carroll-Nellenback, a senior computational scientist at Rochester, Marina Alberti of the University of Washington, and Axel Kleidon of the Max Planck Institute for Biogeochemistry—developed a series of mathematical models to illustrate civilization's potential responses to the dangers of climate change, and what could happen.

Below: The Maya civilization, hailed for its advancements in architecture, agriculture, math and engineering, peaked during the first millennium AD, when it stretched from present-day Mexico to Guatemala and Belize. Evidence indicates climate change in the Yucatán fueled famine, leading to its decline.

They designed their models based in part on case studies of extinct civilizations, including the story of the inhabitants of Easter Island, a Chilean island in the southeastern Pacific Ocean. People began to colonize the island between 400 and 700 AD, and the population grew to 10,000 sometime between 1200 and 1500 AD. By the 18th century, however, after residents used up their resources, the population plummeted to about 2,000 people.

"This is an island in the middle of nowhere," Frank said. "They overused their resources. Once they did that, they couldn't go anywhere. If you've cut down all your trees, you can't build canoes and leave."

Their work appears in the journal Astrobiology. Also, Frank has authored a new book—Light of the Stars: Alien Worlds and the Fate of the Earth—which draws upon this study and explores the dimensions of climate change in a vast universe.

In their study, the authors lay out four possible scenarios:

    Die-off. This is when the population and the state of the planet—its average temperature, for example—increase rapidly. Eventually, the population peaks, then drops quickly as temperatures make it more difficult to survive. The planet reaches a steady population level, but it represents only a fraction of the peak. "Imagine if seven out of ten people you knew died quickly," Frank said.

    Sustainability. Here, the population and the temperature rise, but both eventually reach steady levels without catastrophic consequences. Once people realize the bad effects of using high-impact resources, such as coal and oil, and switch to low-impact resources, such as solar energy and other renewables, everything stabilizes and life goes on with no further harm.

    Collapse without resource change. This occurs when people don't act. The population and temperature both rise rapidly until the population reaches a peak. Then the population drops precipitously. Civilization collapses, although it is unclear whether the species dies out completely.

    Collapse with resource change. The population and temperature increase. People recognize the potential catastrophe and make the switch—but it's too late. Civilization collapses anyway.

"The last scenario is the most frightening, although we can be an example of any of them," Frank said. "As to what is the most likely for us—at this point, I have no idea."

Saqib Qayyum

Below: Between 3,000 and 3,900 years ago, the Indus Valley civilization represented 10 percent of the world's population. It is believed that this ancient civilization suffered from gradual changes in rainfall that created food shortages for its 5 million people.

It's important to be mindful of the broader perspective, he says, that past civilizations outside our realm, but similar to ours, might have endured for several centuries before succumbing to the climate change they created. "Most planets have climates, most planets have atmospheres," he said. "Knowing what we know, we should expect climate change. Any civilization will drive their planet into an anthropocene."

Thus, "if we are not the universe's first civilization, that means there are likely to be rules for how the fate of a young civilization like our own progresses," he added. "Any young population, building an energy-intensive civilization like ours, is going to have feedback on its planet. Seeing climate change in this cosmic context may give us better insights into what's happening to us now—and how to deal with it."

Reposted with permission from our media associate Nexus Media.


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« Reply #1731 on: Jul 13, 2018, 04:12 AM »

Scientists discover a new source of neutrinos in space – opening up another window into the universe

The Conversation
13 Jul 2018 at 13:32 ET                   

Neutrinos – extremely light, ghostly particles that barely interact with matter – have so far only been observed originating from supernovae (exploding stars) and the sun. Now a giant detector at the South Pole has discovered that a “blazar”, a galaxy with a supermassive black hole at its centre, also produces neutrinos.

This is the first time a source of neutrinos in space has been discovered in more than 30 years. What’s more, it’s the first time scientists have observed a neutrino particle with high energy associated with an astrophysical event. This is really exciting news. The observation, just published in Science, opens a completely new chapter in neutrino astronomy.

Neutrinos are fundamental matter particles. The ordinary matter that we are all familiar with is made out of electrons and quarks. We do not observe neutrinos in daily life as they are extremely hard to detect. Theoretical physicist Wolfgang Pauli suggested their existence in 1930, but it took until 1956 before they were first seen by experimental physicists coming from a nuclear reactor.

The reason that they are so hard to detect is because they only weakly interact with ordinary matter. Most neutrinos fly straight through the Earth: they do not interact at all. They do, however, play a very important role in the universe.

For example, when a heavy star explodes at the end of its life, it is known as a supernova – as it shows up as an extremely bright and seemingly new star in the sky. We now know that supernovae emit many more neutrinos than photons (light particles), which we cannot see by eye. Scientists detected the first neutrinos from a supernova in 1987 when a star collapsed just outside our Milky Way.
This unique observation has given us a better understanding of supernovae, as well as the properties of neutrinos themselves.

This event marked the birth of what we call neutrino astronomy. Powerful neutrino telescopes were built soon after. One of them was the Sudbury Neutrino Observatory (SNO). Physicist Art McDonald received the Nobel Prize for Physics in 2015 for the detailed studies of solar neutrinos that he and his team did using this observatory, and the insights this gave us into the properties of the neutrino particles.
Arctic analysis

Another telescope has now grown to be the largest of them all. The IceCube experiment at the South Pole is a cubic kilometre in size and uses deep arctic ice as a target for the neutrinos. Although neutrinos typically don’t interact with anything, they can produce a charged particle when they occasionally do interact with the fundamental particles that make up ice. In IceCube, this resulting particle travels through the ice and produces a trail of faint light.

This trail is captured by a large array of sensitive photodetectors that are mounted up to three kilometres deep into the ice. With this information, IceCube can detect high energy neutrinos, measure their energy and determine where they came from. Other cosmic particles only travel a few kilometres through the Earth, at most. So, if the particle is seen to come up from below, it must have been produced by a neutrino interaction, as it is the only particle that can travel such a large distance through the planet.

The neutrino that was observed by IceCube in September 2017 is very special. This neutrino must have had an extremely high energy – IceCube scientists estimate between 183 and 290 trillion electron volts (a unit of energy). That is 28-45 times more energy than the particles in the beam of the Large Hadron Collider at CERN, the world’s most powerful particle accelerator.

However, neutrinos with even higher energies have been observed by IceCube before. The exciting thing about the new discovery is that it has been shown to come from a blazar, which has been observed by other experiments, such as the FermiLAT satellite and the MAGIC telescope. In a blazar, it is thought that the supermassive black hole at the centre absorbs matter to produce two extremely powerful jets of radiation. These jets could act as powerful particle accelerators.

Blazars were long suspected as a possible source of very high energy neutrinos in the universe, but we now have firm evidence. Together with IceCube, observations of this blazar have been made using telescopes that are sensitive to different types of electromagnetic radiation: radio, optical, gamma ray, and X-ray.

The ConversationWith this observation, IceCube has made a significant step forward in neutrino astronomy. Its neutrino adds new information to the observation of the blazar, helping us to understand these fascinating objects better. It can tell us about the mechanism of particle acceleration in blazars and more about how blazars produce such tremendous amounts of energy. We may even learn something new about the universe, or neutrinos, that we didn’t expect.

By Simon Peeters, Reader (Physics and Astronomy), University of Sussex

This article was originally published on The Conversation. Read the original article.


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« Reply #1732 on: Jul 14, 2018, 05:30 AM »

It Came From a Black Hole, and Landed in Antarctica

For the first time, astronomers followed cosmic neutrinos into the fire-spitting heart of a supermassive blazar.

By Dennis Overbye
NY Times
July 14, 2018

It was the smallest bullet you could possibly imagine, a subatomic particle weighing barely more than a thought. It had been fired out of a gravitational gun barrel by a cosmic blunderbuss, a supermassive black hole.

On Sept. 22, 2017, a particle known as a neutrino zinged down from the sky and through the ice of Antarctica at nearly the speed of light, setting off a cascade of alarms in an array of detectors called IceCube.

Within seconds IceCube had alerted an armada of astronomical satellites, including the Fermi Gamma-ray Space Telescope. That spacecraft traced the neutrino back to an obscure dot in the sky, a distant galaxy known as TXS 0506+056, just off the left shoulder of the constellation Orion, which was having a high-energy outburst of X-rays and gamma-rays.

While astronomers around the world scrambled to their telescopes to get in on the fun, the IceCube scientists scoured their previous data and found that there had been previous outbursts of neutrinos from the galaxy, which they nicknamed the “Texas source,” including an enormous neutrino outburst in 2014 and 2015.

Astronomers said the discovery could provide a long sought clue to one of the enduring mysteries of physics and the cosmos. Where does the rain of high-energy particles from space known as cosmic rays come from?

The leading suspects have long been quasars. They are supermassive black holes in the centers of galaxies where matter and energy get squeezed like toothpaste out of the top and bottom of a doughnut of doomed swirling material in a violent jet.

Now they know at least one in which that seems to be the case. TXS 0506+056 is a type of quasar known as a blazar, in which our line of sight from Earth is along the jet — right down the gun barrel. The term blazar comes partly from BL Lacertae, a starlike object that turned out to be the first of these objects ever recognized.

“We have found the first source of cosmic rays,” said Francis Halzen, of the University of Wisconsin, Madison, and IceCube’s director, in an interview.

“Where exactly in the active galaxy, the neutrinos are produced will be a matter of debate,” he added in an email. “It is clear that the supermassive black hole provides the accelerator power,” he said, but how is a mystery.

The discovery is being announced in a series of papers by an international array of physicists and astronomers in Science and the Astrophysical Journal, and in a news conference sponsored by the National Science Foundation, which funds the IceCube Neutrino Observatory at the Amundsen-Scott South Pole Station.

“I think this is the real thing,” said John Learned, a neutrino expert at the University of Hawaii who is not part of IceCube, in an email, “the true beginning of high energy neutrino astronomy, of which we have dreamed for many decades.” Now, he added, “we  will start seeing into the guts of the most energetic objects in the universe.”

Neutrinos are among the most plentiful particles in the universe — far outnumbering the protons and electrons out of which we are composed. They have no electrical charge and so little mass that it has not been accurately measured yet. They interact with other matter only by gravity and the so-called weak nuclear force and thus flow through us, Earth and even miles of lead like ghosts.

Yet in theory they are all over. Produced by radioactive decays of other particles, they are flooding us from nuclear reactions in the sun, distant supernova explosions and even the Big Bang. The previous great moment in neutrino astronomy happened in 1987, when some 25 neutrinos were recorded in three detectors on Earth coincident with a supernova explosion in the Large Magellanic Cloud, a nearby galaxy.

The lure of neutrinos for astronomy is that it is possible to trace them back to their origins. Not only do they fly long distances and from otherwise impenetrable spots like the cores of stars at virtually the speed of light, but by not having an electrical charge they are not affected by interstellar and intergalactic magnetic fields and other influences that scramble the paths of other types of cosmic particles, like protons and electrons. Neutrinos go as straight through the universe as Einsteinian gravity will allow.

IceCube, an international observatory run by 300 scientists from 12 countries, consists of more than 5,000 sensitive photomultiplier tubes embedded in grid encompassing a cubic kilometer of ice at the South Pole. When a neutrino very, very, very, very, very rarely hits an atomic nucleus in the ice, it produces a cone of blue light called Cerenkov radiation that spreads through the ice and is picked up by the photomultipliers.

IceCube was built, Dr. Halzen said, to find the source of cosmic rays, and the observatory has been recording neutrinos ever since it started working in 2011, but had not been able to pinpoint the sources of any of them until now. One reason, he said, was that the scientists had assumed the sources would be nearby, perhaps even in our own Milky Way galaxy.

But TXS 0506+056,  the Texas source, is very far away, some 4 billion light-years. It is one of the brightest objects in the universe, said Dr. Halzen.

The neutrino that set off the alarm in 2017 had an energy of some 300 trillion electron volts, by the units of energy and mass that physicists prefer. Which means it had been produced by a proton that had been a booster to that energy, nearly 50 times the energy delivered by the Large Hadron Collider at CERN, the biggest particle accelerator on Earth.

Call it the Large Hadron Collider in the sky. Presumably it is some kind of supermassive black hole rumbling in the heart of that distant galaxy. For now, how this cosmic accelerator works in detail is a mystery

Azadeh Keivani, of Pennsylvania State University and lead author of the Astrophysical Journal paper that tried to model it, wrote  that “typically the mass of blazars are about 1 billion solar masses.”

Why is this source so special? Why is it so far away? Those are the questions that need to be answered, Dr. Halzen said. Do such blazars produce all the neutrinos and all the cosmic rays we see?

Luckily an enormous amount of data has been collected from the world’s telescopes over the last few months in what astronomers like to call “multi-messenger astronomy” to give hope of making progress on these and other questions. And the inventory of cosmic neutrinos is only beginning. IceCube has a large and long agenda.

Noting that the Texas source has only erupted twice in the last nine years, Dr. Halzen said, “This is not going to be an everyday event.”

IceCube cost about $250 million to build and almost nothing to operate, because it is all frozen in the ice. Dr. Halzen said he could now operate it from his laptop.

They keep two people on site at the South Pole, he said. “Ideally they have nothing to do.”


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« Reply #1733 on: Jul 16, 2018, 04:29 AM »

The constellation Vela explodes with color (and new suns) in ESO-captured snaps

ZME
6/16/2018

Earlier today, we’ve talked about the first colors complex-ish life created — it was a story of algae, fossils, and pink. Moving on from this daring display by early life, however, I thought we’d seize the occasion to look at what colors accompany birth in the other direction — up in space.

Our eyes can’t peer that far out, but, luckily for us, the European Southern Observatory (ESO) can. Using the HWAK-I (High Acuity Wide field K-band Imager) infrared imager mounted on the Very Large Telescope (VTL) in Chile, the ESO captured some spectacular shots of stars being born in the Vela constellation.

The image depicts the star cluster RCW 38 as seen in infrared. ESO chose this bit of the electromagnetic spectrum for their observations since infrared can see ‘through’ the clouds shrowding star nurseries such as RCW 38. The cluster itself contains hundreds of young, brightly hot, and quite massive stars. Even at the relatively short distance of 5500 light-years away, however, their (visible) light can’t peer through the vast bodies of dust surrounding the cluster.

The central area, seen as a bright blue region, houses numerous very young stars as well as a few protostars — ‘stars’ that are still forming. Observations by the Chandra X-ray Observatory revealed the presence of over 800 X-ray emitting young stellar objects in the cluster. You won’t be surprised to hear, then, that the area is drenched in radiation, making local gas clouds glow vividly. Cooler bodies of dust languishing in front of the cluster carry more subdued, darker hues of red and orange. The end result, a ‘colorful celestial landscape’ as ESO puts it, is quite the striking interplay of color and light.

This image was captured as part of a series of tests — a process known as science verification — for HAWK-I and GRAAL (the ground layer adaptive optics module of the VLT). These tests are performed to ensure newly-commisioned instruments work as intended and include a set of test observations that verify and demonstrate the capabilities of the new instrument.

Previous images of this region — snapped in the visible spectrum — show a very different sight. Optical images appear almost devoid of stars in comparison with those taken in the infrared spectrum due to dust obscuring the view.

Peering through dense bodies such as dust clouds or nebulae is actually one of the HWAK-I’s main roles. The device also projects four laser beams out into the night sky to use as artificial reference stars — used to correct for any atmospheric turbulence, which can bend incoming light — to increase the quality of the final image.

Watch: https://www.youtube.com/watch?v=tvai4hMXSgQ


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« Reply #1734 on: Jul 17, 2018, 04:47 AM »


Against all odds, NASA may have actually found a meteorite on the bottom of the ocean

Mike Wehner
ZME
7/17/2018

Three days ago, scientists from the National Oceanic and Atmospheric Administration teamed up with NASA in the hopes of finding leftover chunks of a meteorite which slammed into the ocean way back in March. NASA had a pretty good idea of where the space rock impacted the ocean, but actually finding any debris was still a long shot. Now it’s beginning to look like the expedition has paid off.

The team spent a solid seven hours exploring the seabed in the area thought to be the site of the meteorite impact, using a pair of robotic vehicles to scour the ocean floor for signs of the very special rock. They gathered a whole bunch of material and used powerful magnets to snag what they hoped would be leftovers of the metallic meteorite.

However, conclusively determining whether any of the material was a leftover chunk of space rock is a tricky task, and despite the high-resolution video feeds from ocean bed it’s impossible tell exactly what any of the rocks were before bringing them back up to the surface.

Once the samples made it back out of the water, the complicated task of sifting through them began. NASA’s Marc Fries, an expert on material from space and Cosmic Dust Curator (now that’s a heck of a job title!) examined the various rocks that were gathered and identified a pair of small chunks that appear to be the real deal.

The rocks are tiny but include features associated with a meteorite that has survived its entry into our atmosphere. The shiny “fusion crust” that appears smooth on their surface suggests they endured the incredible friction of Earth’s atmosphere before eventually plunging into the ocean.

Going forward, researchers will examine the fragments more closely and hope to conclusively determine that they are indeed from space. If the rocks are indeed extraterrestrial, it will mark an incredible accomplishment for the expedition team, and a big win for science as a whole.


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« Reply #1735 on: Jul 18, 2018, 04:35 AM »

‘Oddball’ among 12 new moons discovered around Jupiter

Agence France-Presse
17 Jul 2018 at 14:33 ET                   

A dozen new moons have been discovered around Jupiter, bringing its total number of known moons to 79, the most of any planet in our solar system, astronomers announced Tuesday.

One of the new moons was described as a “real oddball” by researcher Scott Sheppard at the Carnegie Institution for Science, because of its tiny size, it measuring just about a half-mile (one kilometer) across.

It also “has an orbit like no other known Jovian moon” and is “likely Jupiter’s smallest known moon,” he added.

This oddball takes about a year and a half to circle Jupiter, and orbits at an inclined angle that crosses paths with a swarm of moons traveling in a retrograde, or in the opposite direction of Jupiter’s spin rotation.

“This is an unstable situation,” said Sheppard.

“Head-on collisions would quickly break apart and grind the objects down to dust.”

The oddball moon, along with two other new moon discoveries, orbit in the prograde, or same direction as the planet’s rotation.

The inner moons take about a year to circle Jupiter, while the outer moons take twice as long.

All the moons may be fragments that broke apart when their larger, parent cosmic bodies collided.

Astronomers have proposed the name “Valetudo” for the oddball moon, after the Roman god Jupiter’s great-granddaughter, the goddess of health and hygiene.

The Italian astronomer Galileo Galilei discovered the first four of Jupiter’s moons in 1610.

The current team of astronomers did not set out to find new moons of Jupiter, but was scanning the skies for planets beyond Pluto when the moons fell into the path of their telescope.

The new moons were first glimpsed in 2017, using a telescope based in Chile and operated by the National Optical Astronomical Observatory of the United States.

It took a year for their orbits to be confirmed with a series of other telescopes in the United States and Chile.


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« Reply #1736 on: Jul 19, 2018, 04:23 AM »

This is the best photo of Neptune we have so far, and it looks amazing

ZME
7/19/2018

The new image from the European Southern Observatory’s Very Large Telescope (ESO’s VLT) shows just how far our telescopes have come.

The new image was snapped using a new adaptive optics mode called laser tomography — a technique which has shown promise in astronomy as well as in medical research. The technology was made possible by the Multi Unit Spectroscopic Explorer (MUSE), which works with an adaptive optics unit and can correct for the effects of atmospheric turbulence up to one kilometer above the telescope. Using laser tomography, MUSE is able to compensate for almost all of the atmospheric turbulence above the telescope to create much sharper images, with the caveat that it does so over a smaller region of the sky.

With this approach, astronomers were able to bypass the biggest downside of Earth-based telescopes — dealing with the atmospheric disturbances and noise. This is the main reason why we have telescopes like Hubble in space, but if we can do that just as good (or almost just as good) from Earth, it could be a game changer for future observations.

The image of the planet Neptune on the left was obtained during the testing of the Narrow-Field adaptive optics mode of the MUSE instrument on ESO’s Very Large Telescope. The image on the right is a comparable image from the NASA/ESA Hubble Space Telescope. The two images were not taken at the same time so do not show identical surface features. Image Credits: ESO/P. Weilbacher (AIP)/NASA, ESA, and M.H. Wong and J. Tollefson (UC Berkeley).

Compared to pictures taken from the same telescope without the adaptive optics technique, the difference is even more striking.

These images of the planet Neptune were obtained during the testing of the Narrow-Field adaptive optics mode. The image on the right is without the adaptive optics system in operation and the one on the left after the adaptive optics are switched on. Image Credits: ESO/P. Weilbacher (AIP).

The combination of exquisite image sharpness and the spectroscopic capabilities of MUSE will enable astronomers to study the properties of astronomical objects in much greater detail than was possible before. Of course, having sharp images of objects allows you to study them in better detail, and gives astronomers a better chance to understand what they look like and how they were formed.

    “It will enable astronomers to study in unprecedented detail fascinating objects such as supermassive black holes at the centers of distant galaxies, jets from young stars, globular clusters, supernovae, planets and their satellites in the solar system and much more,” says the ESO.

The ESO will continuously update with more photos as their instruments will get a better and better resolution. We can only imagine what these next images will look like, but for now, color me impressed.


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« Reply #1737 on: Jul 20, 2018, 04:20 AM »

We may have just witnessed a close-by star devour the remnants of a planet

A nearby star may have just consumed a planet, NASA reports.

ZME
7/20/2018

Some 450 light years away from Earth, the young star RW Aur A just finished chowing down on a planet — probably.

RW Aur A has captured astronomers’ attention ever since 1937. Nestled in the Taurus-Auriga Dark Clouds, which host stellar nurseries containing thousands of infant stars, its light tends to dim “every few decades for about a month,” according to NASA. Needless to say, this has made researchers very curious ever since we realized it. But then, back in 2011, something happened to throw all this interest into high gear: the star became dimmer far more often, and for longer periods of time.

Watch: https://www.youtube.com/watch?v=MY-y_bhhULM

A groundbreaking feast

To get to the bottom of things, a team of researchers pointed the Chandra X-ray Observatory towards RW Aur A over a five-year period. Chandra is a space telescope first launched in 1999, but which still boasts extremely sensitive X-ray sensors that can make sense of the radiation emitted even by young stars such as RW Aur A.

While young stars can be just as perky as any other, they’re typically shrouded in thick disks of gas, dust, and larger debris — which filter their radiation output and alter their intensity. While this makes less-sensitive instruments practically blind to the shrouded stars, instruments like Chandra can use the ‘filtered’ radiation to estimate what the disks are made of.

And that’s exactly what the team did in this case. According to the paper reporting the findings, Chandra detected surprisingly high levels of iron around RW Aur A. Since previous measurements didn’t record the same concentrations of iron (rather they picked up on much lower levels), the only possible explanation is that an event ejected a huge quantity of the element around the star.

They believe that all this iron came from a planet — or a few planetesimals — colliding with one another around the star. If any one of these bodies was rich in iron, it would explain the high levels seen in the disks around RW Aur A. Chandra recordings in 2017 revealed strong emission from iron atoms, indicating that the disk contained at least 10 times more iron than recordings captured in 2013 during a bright period.

The team speculates that this iron excess comes from a collision of two infant planetary bodies — including at least one object large enough to be a planet — in the space surrounding RW Aur A. Such an event would vaporize a large amount of material from the stars, including some iron. Furthermore, as the larger chunks of debris fall towards the star under its gravitational tug, they would release even more iron as the intense heat breaks them apart and solar winds batter them. Taken together, it would explain the high levels of iron observed in the star’s corona.

Better yet, it would also explain the dimming we see. As this debris falls into the star, it could be physically obscuring its light.

    “If our interpretation of the data is correct, this would be the first time that we directly observe a young star devouring a planet or planets,” says Hans Guenther, who led the study out of MIT’s Kavli Institute for Astrophysics and Space Research.

With this in mind, an alternative explanation is also possible — if far less epic. RW Aur A is part of a binary star system, the sister of (you’ll never guess it) RW Aur B. If small grains of iron-rich particles can become trapped in certain parts of a star’s disk, and if that disk is perturbed by something massive (say, another star) the resulting interplay of tidal forces could stir the iron-rich particles — and make the disk seem richer in iron as all this dust falls into RW Aur A and obscures its light.

The team plans to continue their observations of the star over the next couple of years to see if iron levels stay constant. If they do, it would point to a massive source of iron (i.e. in favor of the collision scenario); if not, the tidal interaction between the two stars would seem like the more likely choice.

    “Much effort currently goes into learning about exoplanets and how they form, so it is obviously very important to see how young planets could be destroyed in interactions with their host stars and other young planets, and what factors determine if they survive,” Guenther says.

Needless to say, I’m rooting for the collision scenario.

The paper “Optical Dimming of RW Aur Associated with an Iron-rich Corona and Exceptionally High Absorbing Column Density” has been published in the journal The Astronomical Journal.


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« Reply #1738 on: Jul 21, 2018, 05:04 AM »

NASA prepares to fly probe into Sun’s scorching atmosphere

Reuters
21 Jul 2018 at 18:38 ET                  

NASA is preparing to send a probe closer to the Sun than any other spacecraft has ventured, enduring wicked heat while zooming through the solar corona to study this outermost part of the stellar atmosphere that gives rise to the solar wind.

The Parker Solar Probe, a robotic spacecraft the size of a small car, is slated to launch from Cape Canaveral in Florida, with Aug. 6 targeted as the launch date for the planned seven-year mission. It is set to fly into the Sun’s corona within 3.8 million miles (6.1 million km) from the solar surface, seven times closer than any other spacecraft.

“To send a probe where you haven’t been before is ambitious. To send it into such brutal conditions is highly ambitious,” Nicola Fox, a project scientist from the Johns Hopkins University Applied Physics Laboratory, told a news conference on Friday.

The previous closest pass to the Sun was by a probe called Helios 2, which in 1976 came within 27 million miles (43 million km). By way of comparison, the average distance from the Sun for Earth is 93 million miles (150 million km).

The corona gives rise to the solar wind, a continuous flow of charged particles that permeates the solar system. Unpredictable solar winds cause disturbances in our planet’s magnetic field and can play havoc with communications technology on Earth. NASA hopes the findings will enable scientists to forecast changes in Earth’s space environment.

“It’s of fundamental importance for us to be able to predict this space weather, much like we predict weather here on Earth,” said Alex Young, a solar scientist at NASA’s Goddard Space Flight Center in Maryland. “In the most extreme cases of these space weather events, it can actually affect our power grids here on Earth.”

The project, with a $1.5 billion price tag, is the first major mission under NASA’s Living With a Star program.

The probe is set to use seven Venus flybys over nearly seven years to steadily reduce its orbit around the Sun, using instruments designed to image the solar wind and study electric and magnetic fields, coronal plasma and energetic particles. NASA aims to collect data about the inner workings of the highly magnetized corona.

The probe, named after American solar astrophysicist Eugene Newman Parker, will have to survive difficult heat and radiation conditions. It has been outfitted with a heat shield designed to keep its instruments at a tolerable 85 degrees Fahrenheit (29 degrees Celsius) even as the spacecraft faces temperatures reaching nearly 2,500 degrees Fahrenheit (1,370 degrees Celsius) at its closest pass.

Reporting by Joey Roulette; Editing by Will Dunham

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« Reply #1739 on: Jul 23, 2018, 04:39 AM »


Saturn’s moon Titan looks absolutely incredible in new infrared images

Mike Wehner
BGR
7/23/2018

NASA’s Cassini orbiter is dead. It’s been dead since late last year, having completed an extended mission and a series of daring dives through Saturn’s iconic rings, and ultimately found itself slamming through the planet’s thick atmosphere where it was essentially vaporized. The spacecraft may be gone but the wealth of data that it sent back to Earth over the years is still being pieced together, and NASA just revealed some images that serve as a fitting example of that.

The images are a series of six infrared snapshots of Saturn’s moon Titan. They’re wildly colorful (thanks to the magic of infrared imaging) and they show the moon in remarkable detail.

Okay, so if the images are as awesome as they clearly are, why are we only seeing them now? Well, these aren’t photos that Cassini snapped as it cruised by — we’d likely have seen them months or even years ago if that were the case — but are actually massive composites of over a decade’s worth of mapping data captured by the spacecraft’s powerful imaging tools.

According to NASA, the images we see here represent 13 years worth of data that the orbiter sent back to Earth, and it’s taken researchers a significant amount of time to piece it all together. Like a massive, multi-layered puzzle, the data used to create these images was gathered at different times and the moon was imaged under different conditions, allowing for the most accurate view of Titan as possible.

“Making mosaics of VIMS images of Titan has always been a challenge because the data were obtained over many different flybys with different observing geometries and atmospheric conditions,” NASA explains in a post.” One result is that very prominent seams appear in the mosaics that are quite difficult for imaging scientists to remove. But, through laborious and detailed analyses of the data, along with time consuming hand processing of the mosaics, the seams have been mostly removed.”


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