When you picture the Solar System in your head, most people would think of the Sun, stolid and stationary in the centre, with everything else whizzing about around it. But every body in the Solar System also exerts its own gravitational tug on the star, causing it to move around just a tiny bit.

Therefore, the precise gravitational centre (or barycentre) of the Solar System is not smack-bang in the middle of the Sun, but somewhere closer to its surface, just outside it. But it hasn't been easy for us to figure out exactly where this barycentre is, due to the myriad gravitational influences at play.

Now, using specially designed software, an international team of astronomers has narrowed down the location of our Solar System's barycentre to within 100 metres (328 feet) - and it could vastly improve our measurements of gravitational waves.

It all has to do with pulsars. These dead stars can rotate extremely fast, on millisecond timescales, shooting beams of electromagnetic radiation from their poles. If they're oriented just right, these beams flash past Earth like a very fast cosmic lighthouse, creating a pulsed signal that's extremely regular.

This regular pulse is useful for all sorts of things, from probing the interstellar medium to apotential navigation system.

In recent years, observatories including the North American Nanohertz Observatory for Gravitational Waves (NANOGrav) have started using them to look for low-frequency gravitational waves, since gravitational waves should causevery subtle disturbancesin the timing of a whole array of pulsars across the sky.

"Using the pulsars we observe across the Milky Way galaxy, we are trying to be like a spider sitting in stillness in the middle of her web," explained astronomer and physicist Stephen Taylor of Vanderbilt University and the NANOGrav Collaboration.

"How well we understand the Solar System barycenter is critical as we attempt to sense even the smallest tingle to the web."

That's because errors in the calculation of Earth's position in relation to the Solar System barycentre can affect our measurements of pulsar timing, which in turn can affect our searches for low-frequency gravitational waves.

Part of the problem is Jupiter. By a very large margin, it has the strongest gravitational effect on the Sun - the tugs of the other planets are minute in comparison. We know how long Jupiter takes to orbit the Sun - about 12 Earth years - but our understanding of this orbit is incomplete.

Previously, estimations of the location of the barycentre have relied on Doppler tracking - how the light from objects changes as we (or our instruments) move towards or away from them - to calculate the orbits and masses of the planets. But any errors in these masses and orbits can introduce errors that might look a lot like gravitational waves.

And when the team used these existing datasets to analyse NANOGrav data, they kept getting inconsistent results.

"We weren't detecting anything significant in our gravitational wave searches between solar system models, but we were getting large systematic differences in our calculations," said astronomer Michele Vallisneri of NASA's Jet Propulsion Laboratory.

"Typically, more data delivers a more precise result, but there was always an offset in our calculations."

This is where the team's software enters the picture. It's called BayesEphem, and it's designed to model and correct for those uncertainties in Solar System orbits most relevant to gravitational wave searches using pulsars - Jupiter in particular.

When the team applied BayesEphem to the NANOGrav data, they were able to place a new upper limit on the gravitational wave background and detection statistics. And they were able to calculate a new, more precise location for the Solar System barycentre that, going forward, could enable much more accurate low-frequency gravitational wave detections.

"Our precise observation of pulsars scattered across the galaxy has localised ourselves in the cosmos better than we ever could before," Taylor said.

"By finding gravitational waves this way, in addition to other experiments, we gain a more holistic overview of all different kinds of black holes in the Universe."

The research has been published in The Astrophysical Journal.

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Astronomers Have Located The Centre of The Solar System to Within 100 Metres - ScienceAlert

A number of astounding astrological phenomena will be visible in 2020. Here's some of what you can look forward to. Accuweather

Scientists have now seen "inside" a planet, a new study said.

This is the first time that weve discovered an intact exposed core of a gas giant (planet) around a star, study lead author David Armstrong, a physicist at the University of Warwick in the U.K., said in a statement.

The discovery offers the unique opportunity to peer inside the interior of a planet and learn about its composition, according to the university.

The star and the planetary core, known as TOI-849b, are some 730 light-years away from Earth. The star is similar to our sun and the core is about the same size as Neptune.

TOI-849b is an extremely unusual exoplanet in the so-called "Neptune Desert" a term used by astronomers for a region close to stars where we rarely see planets of Neptunes mass or larger. An exoplanet is a planet that orbits stars other than our sun.

Otherworldly: 'Nearby' star may have three Super-Earths

So what happened to the gaseous atmosphere that surrounded this planetary core? One theory is that the gas was somehow stripped away, perhaps during a tidal disruption, where the planet is ripped apart from orbiting too close to its star, or even a collision with another planet.

Artist's impression: The surviving core of a gas giant has been discovered orbiting a distant star. It is extremely rare to find an object of this size and density so close to its star.(Photo: University of Warwick/Mark Garlick)

Another theory is that it never had a gaseous atmosphereat all, which would make it a "failed gas giant." This means that once the core of the gas giant formed, then something could have gone wrong and it never formed an atmosphere.

The discovery is just the beginning of the research, scientists said:

Its a first, telling us that planets like this exist and can be found," Armstrong said. "We have the opportunity to look at the core of a planet in a way that we cant do in our own solar system."

Hello out there: Scientists are searching the universe for signs of alien civilizations: 'Now we know where to look'

"There are still big open questions about the nature of Jupiters core, for example, so strange and unusual exoplanets like this give us a window into planet formation that we have no other way to explore," he said.

The study was published Wednesday in the peer-reviewed British journal Nature.

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First planetary core discovered, astronomers announce - USA TODAY

Large stars have violent deaths. As they run out of hydrogen to fuse, the stars weight squeezes its core to make it increasingly hot and dense. The star fuses heavier elements in a last-ditch effort to keep from collapsing. Carbon to Silicon to Iron, each step generating heat and pressure. But soon its not enough. The fusion even heavier elements dont give the star more energy, and the core quickly collapses. The protons and neutrons of nuclei collide so violently that the resulting shock wave rips the star about. The outer layers of the star are thrown outward, becoming a brilliant supernova. For a brief time, the star shines brighter than its entire galaxy, and its core collapses into a neutron star or black hole. It was thought that all large stars end with a supernova, but new research finds that might not be the case.

The evidence comes from a galaxy 75 million light-years away known as the Kinman Dwarf Galaxy. Between 2001 and 2011, several groups of astronomers were studying the spectra of this galaxy because it has a particularly low metallicity. Because the galaxy is small and far away, astronomers cant see all the individual stars, but the galactic spectra allow them to identify some of the bright stars by particular emission lines. One of these was a luminous blue variable star.

Luminous Blue Variables (LBVs) are very large stars in their elder days. They have active and quiet periods and can shine 2.5 million times brighter than the Sun. The bright emission lines of LBVs are unusual for a blue giant star, so they are easy to identify. Since astronomers saw these lines in the spectra of the Kinman Dwarf Galaxy, they knew the galaxy contained such a star.

But when new spectra measurements of the Kinman Dwarf Galaxy were taken in 2019, the spectral lines of the LBV were gone. They had simply vanished as if the star wasnt there. It seemed the star had disappeared. But giant blue stars dont just disappear. They should explode as a supernova before fading away. This particular star didnt become a supernova, so something strange is going on.

Since astronomers havent observed the star directly, its possible that the star did become a supernova and we happened to miss it. But that is highly unlikely. The Kinman Dwarf Galaxy is regularly observed, and a supernova would be difficult to miss. Its more likely that the star did fade from view, and the authors of this latest research have a couple of ideas why.

One idea is that the star has entered a particularly quiet stage at the same time it happens to be obscured by dust in the galaxy. But a second idea is more interesting. Perhaps the star underwent an unusual core collapse, forming a black hole without undergoing a supernova. There has been some debate over whether this is possible, and this new work could be evidence to support the idea.

But this is only one star and not even one that was directly imaged. It will take much more work to determine what really happened.

Reference: Allan, Andrew P., et al. The possible disappearance of a massive star in the low-metallicity galaxy PHL 293B. Monthly Notices of the Royal Astronomical Society 496.2 (2020): 1902-1908.

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Astronomers Might Have Seen a Star Just Disappear. Turning Straight to a Black Hole Without a Supernova - Universe Today

If you're feeling like you could use something new and different to watch to take your mind off the state of the world, consider the Sun.

NASA has released a video, embedded below, that shows it in a way you probably have never seen, and maybe never even imagined.

The video shows an entire decade of activity on the Sun in the span of a single episode of, well, name your favorite television series. If you're anything like me (a proud science visualization geek), and probably even if you're not, you might find it mesmerizing. (The music helps!)

The video is a time-lapse consisting of one high-resolution photo taken every hour of every day by the Solar Dynamics Observatory between June 2, 2010 and June 1 of this year. It condenses those 10 years into just 61 minutes.

A number of particularly noteworthy solar events that are part of the Suns 11-year solar cycle are captured in the video, including eruptions, flares, explosions, prominences, etc. These features tend to go by quickly and are easy to miss. So I've also included visualizatons that capture some of these spectacular events in great detail, along with short explanations.

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Up close and personal: 10 years in the life of the Sun - Astronomy Magazine

Planet AU Mic b is about the size of Neptune. Credit: NASAs Goddard Space Flight Center/Chris Smith (USRA)

An exoplanet the size of Neptune has been discovered around the young star AU Microscopii, thanks in part to the work of Jonathan Gagn, a former iREx Banting postdoctoral researcher who is now a scientific advisor at the Rio Tinto Alcan Planetarium.

Astrophysicists have been searching for exoplanets in this system, a unique laboratory for studying planetary formation, for more than a decade. The breakthrough, announced today in Nature, was made possible in part by NASAs TESS and Spitzer space telescopes.

Located about 32 lightyears from Earth, AU Microscopii, or AU Mic, is a young star between 20 and 30 million years old, which is about 180 times younger than our own Sun. In the 2000s, it was found to still be surrounded by a large disc of debris, a remnant of its formation. Since then, astrophysicists have been actively searching for planets around AU Mic, since it is within such discs of dust and gas that they form.

AU Mic is a small star, with only about 50 percent of the Suns mass, said Gagn, who participated in the observations and data processing. These stars generally have very strong magnetic fields, which make them very active. That explains in part why it took nearly 15 years to detect the exoplanet, called AU Mic b. The numerous spots and eruptions on the surface of AU Mic hampered its detection, which was already complicated by the presence of the disc.

Illustration of AU Mic b orbiting its parent star, AU Mic. Credit: NASAs Goddard Space Flight Center/Chris Smith (USRA)

Jonathan Gagn at the summit of Mauna Kea, where astrophysicists have been searching for a planet around AU Mic since 2010. Credit : Jonathan Gagn. In 2010, a team led by Peter Plavchan, now an assistant professor at George Mason University, began observing AU Mic from the ground using NASAs Infrared Telescope Facility (IRTF).

The telescope operates in the infrared, where the team hoped to see the signal of the planet better, since the stars activity is less intense in this type of light.

For his part, Gagn made numerous observational trips to the IRFT during his doctoral studies. That is when he became involved in the project. A few years after I joined the team, we noticed a possible periodic variation in the radial velocity of AU Mic, he recalled.

We were thus made aware of the plausible presence of a planet around it. As a planet orbits, its gravity tugs on its host star, which moves slightly in response. Sensitive spectrographs such as the one on the IRTF can detect the stars radial velocity, its motion to-and-fro along our line of sight.

Au Mic is a red dwarf, the most numerous type of star in the galaxy. Credit: NASAs Goddard Space Flight Center/Chris Smith (USRA)

The accuracy of the data obtained on the ground was unfortunately not sufficient to confirm without a doubt that the signal was due to an exoplanet. Its thanks to the transit method, a different detection technique, that the team was finally able to confirm the presence of AU Mic b.

A transit occurs when a planet passes directly between its host star and the viewer, periodically hiding a small fraction of its light. Astronomers observed two transits of AU Mic b during NASAs Transiting Exoplanet Survey Satellite (TESS) first mission, in the summer of 2018. They then observed two more with NASAs Spitzer Space Telescope in 2019.

Since the amount of light blocked depends on the size of the exoplanet and its distance from its star, these observations allowed scientists to determine that AU Mic b is about the size of Neptune, and that it passes in front of its star every 8.5 days.

Thanks to previous ground-based observations, the team also has a partial constraint on the mass of AU Mic b. Combining IRTFs observations with data obtained at the European Southern Observatory in Chile and the W. M. Keck Observatory in Hawaii, they concluded that its mass is less than about 3.4 times the mass of Neptune (or 58 times that of Earth).

AU Mic provides a unique laboratory to determine how exoplanets and their atmospheres form, and how they interact with the disc of debris and gas from which they are born.

Scientists are excited about their latest discovery, as very few systems like AU Mic are known. Not only is the detection of exoplanets difficult in these systems, but they are also very rare because a systems period of planetary formation is relatively short compared to the life of a star.

The AU Mic system is close to Earth and therefore appears brighter, allowing astrophysicists to observe it with a range of instruments. such as the SPIRou spectrograph.

This instrument, with its polarimetric capabilities, will allow us to better distinguish the effects of stellar activity, which are often confused with the signal from the planets, said Etienne Artigau, a project scientist at Universit de Montral. This will allow us to determine the mass of AU Mic b accurately and to know if this exoplanet is more like a large Earth or a Neptune twin.

Other iREx astronomers are enthusiastic about trying to detect the planets atmosphere, and see the effect of the active star on it. These observations can also be accomplished with SPIRou.

AU Mic is part of an association of young stars that formed at about the same time in the same place. Beta Pictoris, the star that gives its name to this association, also has a disc and two known planets.

Both the star and the planets are however considerably more massive (1.75 times the mass of the Sun, and 11 and nine times the mass of Jupiter, respectively). They do not appear to have evolved in the same way as AU Mic and its planet. Studying these two systems, which have many characteristics in common, scientists can compare two very different scenarios of planetary formation.

Many surprises undoubtedly still hide within AU Mics system, the iREX researchers believe. Will further observations of the system with TESS confirm the existence of other planets? Is the atmosphere of the planet outgassing because of the strong stellar activity? How does this system compare to others of the same age? Those are all questions for future study.

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Reference: A planet within the debris disk around the pre-main-sequence star AU Microscopii by Peter Plavchan, Thomas Barclay, Jonathan Gagn, Peter Gao, Bryson Cale, William Matzko, Diana Dragomir, Sam Quinn, Dax Feliz, Keivan Stassun, Ian J. M. Crossfield, David A. Berardo, David W. Latham, Ben Tieu, Guillem Anglada-Escud, George Ricker, Roland Vanderspek, Sara Seager, Joshua N. Winn, Jon M. Jenkins, Stephen Rinehart, Akshata Krishnamurthy, Scott Dynes, John Doty, Fred Adams, Dennis A. Afanasev, Chas Beichman, Mike Bottom, Brendan P. Bowler, Carolyn Brinkworth, Carolyn J. Brown, Andrew Cancino, David R. Ciardi, Mark Clampin, Jake T. Clark, Karen Collins, Cassy Davison, Daniel Foreman-Mackey, Elise Furlan, Eric J. Gaidos, Claire Geneser, Frank Giddens, Emily Gilbert, Ryan Hall, Coel Hellier, Todd Henry, Jonathan Horner, Andrew W. Howard, Chelsea Huang, Joseph Huber, Stephen R. Kane, Matthew Kenworthy, John Kielkopf, David Kipping, Chris Klenke, Ethan Kruse, Natasha Latouf, Patrick Lowrance, Bertrand Mennesson, Matthew Mengel, Sean M. Mills, Tim Morton, Norio Narita, Elisabeth Newton, America Nishimoto, Jack Okumura, Enric Palle, Joshua Pepper, Elisa V. Quintana, Aki Roberge, Veronica Roccatagliata, Joshua E. Schlieder, Angelle Tanner, Johanna Teske, C. G. Tinney, Andrew Vanderburg, Kaspar von Braun, Bernie Walp, Jason Wang, Sharon Xuesong Wang, Denise Weigand, Russel White, Robert A. Wittenmyer, Duncan J. Wright, Allison Youngblood, Hui Zhang and Perri Zilberman, 24 June 2020, Nature.DOI: 10.1038/s41586-020-2400-z

About the study

A planet within the debris disk around the pre-main-sequence star AU Microscopii was published on June 25, 2020 in Nature. In addition to Jonathan Gagn (iREx, Universit de Montral, Space for Life), the research team includes first author Peter Plavchan from George Mason University; second author Thomas Barclay, an associate research scientist at the University of Maryland, Baltimore County and an associate project scientist for TESS at NASAs Goddard Space Flight Center in Greenbelt, Maryland; and 82 other co-authors, including former iREx member David Berardo, now a PhD student at MIT.

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Exoplanet the Size of Neptune Discovered by Astronomers About 32 Light-Years From Earth - SciTechDaily

Galileo Galilei was the first person to point a telescope at the night sky. Having gazed heretically upon very large and distant celestial bodies, he realised he could use the same technology to magnify smaller terrestrial ones closer to home. Lenses with a shorter focal length enabled Galileo to squint at insects as well as planets. He called the new device his occhiolino, or little eye. We call it the microscope.

Today scientists apply technology across similarly vast differences of scale. By observing how the light of distant stars passes through interstellar gas and dust, astronomers have been able to interpret what exists in the outer reaches of space. Now, researchers from Exeter University in Britain are using the same technique to detect breast cancer.

The team, which comprises medical physicists and astronomers, is using the same code that has been applied to starlight to model how the light of a laser penetrates breast tissue. They are searching for small shifts in the wavelength of light that may signify the tell-tale presence of calcium deposits created by breast cancer. This method of cancer detection has the potential to be more accurate than a standard mammogram, and could eventually be used to find different types of cancer as well as other diseases.

Astronomers are looking at the way light moves from a distant star and goes through interstellar gas and hits our eye, says Charlie Jeynes, who is part of the team at Exeter. Were using that exact same process to look at the way light comes out of a laser, goes through breast tissue and hits a detector.

Other scientists are looking to the stars for inspiration to fight heart disease. A team from the University of Hertfordshire in Britain has been investigating how machine-learning techniques developed in astronomy could be turned towards medical imaging.

In distant galaxies, one of the things we look at is the very centre; an environment called the circumnuclear region, explains Jim Geach, a professor of astrophysics at Hertfordshire. By identifying patterns in the way light is emitted and absorbed in this region, astronomers can learn about a galaxys composition. Working with Richard Underwood, a professor of cardiac imaging at the Royal Brompton Hospital in London, Geach found that a remarkably similar approach could also help to identify patterns of dying or diseased tissue in the human heart: We got talking and realised the data he was looking at, these 3d scans of the heart, closely resembled some of the data we look at in astrophysics.

Galileo would surely have approved. To solve the hardest problems, sometimes all thats required is a change of perspective.

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How stargazing could save your life | 1843 - The Economist 1843

A nurse protests Chile's handling of the coronavirus pandemic. The country now has the highest per capita infection rate of any major country 13,000 cases for every 1 million people. Marcelo Hernandez/Getty Images hide caption

A nurse protests Chile's handling of the coronavirus pandemic. The country now has the highest per capita infection rate of any major country 13,000 cases for every 1 million people.

Chile looked as if it were well prepared to deal with the new coronavirus.

It's a rich country classified as high income by the World Bank. Life expectancy is roughly 80 years better than the United States'. It has a solid, modern health care system, and when the outbreak began spreading, officials made sure they had plenty of ventilators and intensive care beds at the ready.

But the virus exploited the cracks in Chilean society. The country now has the highest per capita infection rate of any major country 13,000 cases for every 1 million people. That's more than 10 times the rate in neighboring Argentina and twice the rate in Brazil.

Like many well-to-do countries, Chile saw its first cases of COVID-19 among its elite people who'd recently traveled to Europe and the United States. That was in April. The government quickly rolled out a plan to provide testing and treatment. Health officials quarantined hard-hit neighborhoods. Residents had to apply for a pass online before they could go out of their homes even to buy groceries. In late April, things were going so well that Chile was starting to talk about reopening.

"And then May started bringing more cases and more cases. Currently we have, in my opinion, more cases than we are able to handle," says Thomas Leisewitz, a physician in Santiago. Leisewitz is a professor at Pontificia Universidad Catlica de Chile and heads up strategic development at Red de Salud UC Christus, a nonprofit Catholic health care network.

Since May, the number of cases has been rising steadily, with the country recording at one time 5,000 to 6,000 new cases a day in June. The virus spread out of the affluent parts of Santiago to low-income neighborhoods where many residents don't have the luxury of being able to work from home.

And the high numbers are not just a reflection of an efficient testing infrastructure. Chile's per capita testing rate is lower than most European nations' and almost half the rate in the United States.

So how did this particular virus come to spread incredibly rapidly in wealthy, well-prepared Chile?

Andrea Insunza, a journalist in Santiago, says the reason is something unrelated to the virus itself. That something is social inequity.

"In Chile, there are two countries," says Insunza, who runs the center for investigative journalism at Universidad Diego Portales. "There's a country for people like me. I have a good education. I have a good salary, and all my social security is privatized."

By this she means she has access to high-quality private hospitals and clinics.

But there's another Chile.

"And that Chile is poor and you depend on the public health [system]," says Insunza.

Last October, violent street protests erupted in Santiago over a fare hike on the subway of 30 pesos, or less than 5 U.S. cents.

The protests became about far more than the price of a subway ride. Chile is one of the most unequal countries in Latin America, according to the World Bank. The elite, the top 10%, controls more than half the country's wealth. And while extreme poverty has been driven down significantly over the last decade, the social unrest in October centered on the frustrations of lower- and middle-class Chileans who view their economic opportunities as unfairly limited.

Insunza says part of the frustration is driven by the elite often not even seeming to recognize their privileged lifestyles.

"Santiago, it's a very segregated place," Insunza says. "You can actually live your whole life and don't see poverty. Never."

Chile's initial plan to deal with the coronavirus outbreak which at first affected mainly the elite in Santiago failed to recognize that the affluent have maids, gardeners and cooks who might also get infected.

The country's response went well in those early weeks. Case numbers were holding steady. The fatality rate was low.

Then the virus started spreading in lower-income neighborhoods and quickly got out of control.

"One thing that's interesting about Chile is that it probably has more state capacity in a technical way than any place in Latin America," says James Robinson, a professor at the University of Chicago and co-author of Why Nations Fail. He has written extensively about Latin America and, in particular, Chile.

"It's good at raising taxes and building roads and infrastructure," he says. "And there's not much corruption and things like that, but it's also a very polarized place."

Robinson says large segments of the public don't trust the state. They are wary of cooperating with government, which may be part of what has hindered Chile's response to the coronavirus outbreak.

In June, the health minister stepped down over his handling of the crisis and discrepancies over the case numbers he reported domestically, which were lower than the counts given to the World Health Organization.

President Sebastin Piera caused an uproar last week when he attended the funeral of his uncle along with more than 30 other people, while the government's coronavirus rules allow only 20 people at funerals.

Despite the government offering cash support and food to people who've lost work because of the lockdowns, Robinson says many Chileans feel that the system is stacked against them. And that's impeding the country's ability to tackle this virus.

"There's a real problem with the social contract in Chile," he says. "And the way they tried to manage this thing just seems to have sort of exacerbated a lot of those problems."

Chile has now extended lockdowns to more areas and put in tougher limits on movement to try to rein in the surging outbreak. In Santiago, residents who are not deemed essential workers are only being allowed to leave their houses twice a week, including trips for grocery shopping.

The regional office of the World Health Organization, the Pan American Health Organization, predicts that cases will continue to rise in Chile at least into the middle of July.

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Social Divisions Drive Astronomical COVID-19 Rate In Chile : Goats and Soda - NPR