The 2017 Solar Eclipse May Prove the Sun Is Bigger Than We Think

A growing number of researchers think that the Sun is actually larger than commonly thought.

Scientists don’t know the Sun’s size as precisely as the details of the Earth and moon, making it a sticking point for perplexed eclipse modelers.

Xavier Jubier creates detailed models of solar and lunar eclipses that work with Google Maps to show precisely where the shadow of the Sun will fall on the Earth, and what the eclipse will look like at each point. He came to realize there was something off about the sun’s measurements as he matched his eclipse simulations with actual photos. The photos helped him identify exactly where an observer had been for historical eclipses — but those precise eclipse shapes only made sense if he scaled up the Sun’s radius by a few hundred kilometers.

“For me, something was wrong somewhere, but that’s all I could say,” Jubier told Space.com.

Scientists’ knowledge of the Earth’s and moon’s contours weren’t exact enough to highlight this discrepancy until about 10 years ago — the same time that modern eclipse simulations became possible through computer power and precision mapping. So it was around then that Jubier began to realize something was amiss.

NASA researcher Ernie Wright came to a similar conclusion as he began to create increasingly precise models of solar eclipses, starting about two years ago. He, too, had to scale up the sun slightly from the traditional size for his calculations to match reality.

“How can you not know this?” Wright recalls thinking. “You just hold a ruler up to the sky, and you say it’s this big.”

But as it turns out, it’s not that simple, Wright told .

Where did it come from?

Historically, researchers have used the value 696,000 km as the radius of the sun’s photosphere — the body of the sun whose wavelengths are visible to the naked eye on Earth. The value was first published in 1891 by the German astronomer Arthur Auwers, Wright said, and it was taken as a standard value for quite some time. In 2015, the International Astronomical Union defined a “unit” based on the sun’s radius as a similar 695,700 km, based on a 2008 study, so researchers can use that value to compare the sizes of other stars in the universe.

But efforts to measure the sun’s radius have never been accurate enough to match our knowledge of the moon’s and the Earth’s contours, the researchers said. Scientists have tried measuring it through transits of Mercury and Venus — when those planets cross the face of the sun — and through images taken from sun-observing satellites like the Solar Dynamics Observatory. Each pixel on SDO images covers about 90 miles (150 km), Wright said, which means there’s a limit to how precisely the size of the photosphere can be measured with this method. In addition, orbiting solar telescopes like SDO generally collect wavelengths of light emitted deeper inside or further outside the Sun, rather than its visible photosphere.

“It’s harder than you think just to put a ruler on these images and figure out how big the Sun is — [SDO] doesn’t have enough precision to nail this down,” Wright said. “Similarly, with the Mercury and Venus transits, it turns out [a measurement based on those is] not quite as precise as you’d like it to be.”

Different papers trying to pin down the sun’s radius, using planet transits, space-based sensors as well as ground observations, have produced results that differ by as many as 930 miles (1,500 km), and can’t seem to be reconciled with one another, Wright said. And for eclipse modelers, it’s a critical and irritating problem.

Eclipse viewers might find the uncertainty of interest, as well, as they plot out where they’ll be in the path of totality. A slightly larger sun means the period of total blackout can be a few seconds shorter in the center of the path, and the path itself would warp, as well.

“For most people, yes, it doesn’t really matter; it won’t change everything,” Jubier said. “But the closer you get to the edge of the [eclipse] path, the more risk you take.” If the sun is indeed bigger, the path is narrower than projections made with the usual value would suggest. So those chasing the effects on the eclipse’s edge could be in trouble if they’re not using a large enough value for their calculations.

Few people do eclipse predictions, Jubier added, and the precise value isn’t necessary to a lot of researchers. Because of that, definitions can vary and it’s hard to compare different values to one another, including the original 1891 value. It can be hard to tell for a given study what assumptions went into their answer for the Sun’s diameter, and so they can’t be adapted easily to match each other or the eclipse. Any discrepancies in eclipse measurements can be attributed to not fully understanding the values, Jubier added.

“It is definitely still an area of ongoing research, and something that the field itself is interested in getting a better handle on,” C. Alex Young, a solar astrophysicist at NASA’s Goddard Space Flight Center in Maryland, told Space.com. “Probably a little esoteric for many people, and I would say that the calculation is not as important for a lot of areas, for example in solar physics, in terms of the accuracy needed. But especially the eclipse community is very interested in the accuracy.”

Figure it out

Michael Kentrianakis, an avid eclipse chaser and a member of the American Astronomical Society’s Solar Eclipse Task Force, learned about the confusion over the sun’s size from his colleague Luca Quaglia, a physicist and eclipse researcher.

“The straw that broke the camel’s back,” Kentrianakis said, came during an expedition to Argentina in February, where he positioned himself outside what should have been the edge of an annular eclipse — where the moon is circled by a bright “ring of fire.” A larger Sun would make the “ring of fire” effect visible to a wider area.

“Technically, I should have been outside of annularity, [but the unfiltered photographs show] we were still in the path of annularity, and we have this beautiful chromosphere circling around at the edge,” Kentrianakis said. That experience fully convinced him the Sun was larger than generally thought.

This upcoming eclipse — which will very likely be the most-watched total solar eclipse in history, NASA officials have said — will provide a chance for others inside and outside the path of totality to help verify its size.

While researchers would ordinarily use the radius of the Sun to compute exactly when the moon will cover and uncover the sun for a given location, called contact times, the opposite strategy is required here, Quaglia told Space.com. “If we can measure contact times accurately, everything else being the same, the only thing that can change is the solar radius. We can actually compute the solar radius that way,” he said.

Kentrianakis, Jubier, Quaglia and others want to pin it down by positioning researchers inside and outside where totality should be, armed with the equipment for what’s called a “flash spectrum” photograph. The process uses a textured grating over a camera, which splits incoming light into component wavelengths — making it easy to determine precisely when the entire photosphere has been covered by the moon, revealing a more limited set of wavelengths emitted by the chromosphere. Combined with accurate timestamps, that process would provide strong evidence for the Sun’s size. (Such a process has been used before, but on a limited scale, Quaglia said.)

Such measurements would also provide another benefit, Jubier said — investigating what some think is a thin layer in between the photosphere and chromosphere called the mesosphere. That thin layer can be visible for a moment after the photosphere is blotted out during an eclipse, which means observers may make measurements that confuse the mesosphere for more of the photosphere. A flash spectrum can help distinguish between the two, although it must be a high enough resolution so the signals from each can be clearly separated.

A group involving Quaglia, Kentrianakis and Jubier was unable to get funding for as broad a flash-spectrum experiment as they would have liked — something like 30 separate measurement stations arrayed just inside and just outside the predicted eclipse path. But researchers could still use crowdsourced data and measurements during the eclipse to learn more.

“The more observations we have the better even if they are not providing the kind of quality we expected to get from the cinematographic spectroscopy,” Jubier said. “Time will tell what we can make of all this.”

Jubier said that flash spectrum measurements would be most useful, but so would (safely!) unfiltered views of the eclipse. Most filters cut out details of the images, making it much more difficult to determine precisely when the Sun fully covers the moon.

Other groups will also be using the eclipse to try and measure the Sun’s diameter, Quaglia said, including the International Occulting Timing Association, which will analyze smartphone videos taken at intervals perpendicular to the eclipse path in Nebraska.

“The more people, the more techniques, the more teams involved will get us there as a whole,” Quaglia said. “If, then, the International Astronomical Union makes the decision to change the value, they will probably not change the value lightly.”

Understanding the visible sun’s exact size will be possible only by combining careful solar measurements with the simulations and precise understanding of the moon’s and Earth’s elevations that exist now, Jubier said. But the pieces are in place to make that determination, if enough people get on board to measure the most common sight in the sky during those uncommon moments of eclipse.

“It’s big, and it will take many eclipses — it may take until 2024 — but at least we’re starting it now,” Kentrianakis said.

BREAKING NEWS: Cosmic Ray Penetration More Prevalent Than Realized – Photos

Cosmic Ray bolts have been caught on camera showing extremely rare footage of this phenomenon sometimes described as Gigantic Jets or Stratospheric Thunder Bolts. These events are related to another celestial phenomenon known as “sprites” – both of which is the penetration of galactic cosmic rays through Earth’s upper and lower atmosphere.

As mentioned in my recent article “Large CME Explodes on Farside of Sun”, the latest research shows cosmic ray dose rates have increased up to 20% in just the last year. My research suggest this has an influence of Earth’s core by increasing temperatures causing Earth to compensate for maintaining its ambient temperature. This is done by sweating…. Just as us humans sweat through our pores to manage an overheated body, the Earth sweats by releasing magma through its pores known as ‘mantle plumes’.

As evidenced by space weather balloons over the last two years, a steady increase in deep space radiation is penetrating our atmosphere. This increase is largely due to the decline in the solar activity and a weakening magnetic field. This cyclical trend is expected to continue for a few years. I expect we will see an increase in these galactic cosmic ray thunderbolts.

Thank you for your continued support. We’re now about half way there.

Remember, you do not need a PayPal account to use your card.

Watch for ongoing reports as information comes in. I also plan to present greater outlines to the science behind by research, especially for those who may be new to my work.

Conductivity Key To Mapping Water Inside Earth

Hydrogen at elevated temperature creates high electrical conductivity in the Earth’s mantle.

New work by Lawrence Livermore National Laboratory (LLNL) scientists shows the dispersal of water (incorporated as hydrogen in olivine, the most abundant mineral in the upper mantle), could account for high electrical conductivity seen in the asthenosphere (part of the upper mantle just below the lithosphere that is involved in plate tectonic movement). The research appears in Scientific Reports .

The work could lead to a better understanding of present day water distribution in the mantle, which has strong implications for planetary dynamics and evolution. Researchers said such information might provide key evidence as to why Earth is the only known planetary body in our solar system to develop plate tectonics and to retain liquid water oceans on its surface.

“We approached the problem from a different perspective, using new hydrogen diffusion measurements to infer what the contribution of hydrogen would be to electrical conductivity,” said LLNL’s Wyatt Du Frane, the principal investigator on the project. “Our experiments on olivine indicated a larger temperature dependence than previously thought to occur for this phenomenon. The contribution of hydrogen to electrical conductivity, while modest at lower temperatures, becomes quite large at the temperatures expected to occur in the mantle.”

Minerals formed deep in the mantle and transported to the Earth’s surface contain tens to hundreds of parts per million in weight (ppm wt) of water, providing evidence for the presence of dissolved water in the Earth’s interior. Even at these low concentrations, water greatly affects the physico-chemical properties of mantle materials. The diffusion of hydrogen controls the transport of water in the Earth’s upper mantle, but until now was not fully understood for olivine.

Earth’s hydrosphere is a distinctive feature of our planet where massive oceans affect its climate and support its ecosystem. The distribution of water on Earth is not limited to its outermost shell (hydrosphere and hydrated minerals), but extends to great depths within the planet. Downwelling oceanic lithosphere (at subduction zones) and upwelling magmas (at mid ocean ridges, volcanoes and hotspots) are vehicles for transport of H2O between the surface and the Earth’s deep interior.

“The amount of hydrogen required to match geophysical measurements of electrical conductivity inside Earth are in line with the concentrations that are observed in oceanic basalts. This demonstrates that geophysical measurements of electrical conductivity are a promising tool for mapping out water distributions deep inside the Earth,” Du Frane said.

Gamma-Ray Burst Captured In Unprecedented Detail

Gamma-ray bursts are among the most energetic and explosive events in the universe. They are also short-lived, lasting from a few milliseconds to about a minute. This has made it tough for astronomers to observe a gamma-ray burst in detail.

Using a wide array of ground- and space-based telescope observations, an international team led by University of Maryland astronomers constructed one of the most detailed descriptions of a gamma-ray burst to date. The event, named GRB160625B, revealed key details about the initial “prompt” phase of gamma-ray bursts and the evolution of the large jets of matter and energy that form as a result of the burst. The group’s findings are published in the July 27, 2017 issue of the journal Nature.

“Gamma-ray bursts are catastrophic events, related to the explosion of massive stars 50 times the size of our sun. If you ranked all the explosions in the universe based on their power, gamma-ray bursts would be right behind the Big Bang,” said Eleonora Troja, an assistant research scientist in the UMD Department of Astronomy and lead author of the research paper. “In a matter of seconds, the process can emit as much energy as a star the size of our sun would in its entire lifetime. We are very interested to learn how this is possible.”

The group’s observations provide the first answers to some long-standing questions about how a gamma-ray burst evolves as the dying star collapses to become a black hole. First, the data suggest that the black hole produces a strong magnetic field that initially dominates the energy emission jets. Then, as the magnetic field breaks down, matter takes over and begins to dominate the jets. Most gamma-ray burst researchers thought that the jets were dominated by either matter or the magnetic field, but not both. The current results suggest that both factors play key roles.

“There has been a dichotomy in the community. We find evidence for both models, suggesting that gamma-ray burst jets have a dual, hybrid nature,” said Troja, who is also a visiting research scientist at NASA’s Goddard Space Flight Center. “The jets start off magnetic, but as the jets grow, the magnetic field degrades and loses dominance. Matter takes over and dominates the jets, although sometimes a weaker vestige of the magnetic field might survive.”

The data also suggest that synchrotron radiation — which results when electrons are accelerated in a curved or spiral pathway — powers the initial, extremely bright phase of the burst, known as the “prompt” phase. Astronomers long considered two other main candidates in addition to synchrotron radiation: black-body radiation, which results from the emission of heat from an object, and inverse Compton radiation, which results when an accelerated particle transfers energy to a photon.

“Synchrotron radiation is the only emission mechanism that can create the same degree of polarization and the same spectrum we observed early in the burst,” Troja said. “Our study provides convincing evidence that the prompt gamma-ray burst emission is driven by synchrotron radiation. This is an important achievement because, despite decades of investigation, the physical mechanism that drives gamma-ray bursts had not yet been unambiguously identified.”

Comprehensive coverage of GRB160625B from a wide variety of telescopes that gathered data in multiple spectra made these conclusions possible, the researchers said.

“Gamma-ray bursts occur at cosmological distances, with some dating back to the birth of the universe,” said Alexander Kutyrev, an associate research scientist in the UMD Department of Astronomy and a co-author of the research paper. “The events are unpredictable and once the burst occurs, it’s gone. We are very fortunate to have observations from a wide variety of sources, especially during the prompt phase, which is very difficult to capture.”

NASA’s Fermi Gamma-ray Space Telescope first detected the gamma-ray emission from GRB160625B. Soon afterward, the ground-based MASTER-IAC telescope, a part of Russia’s MASTER robotic telescope network located at the Teide Observatory in Spain’s Canary Islands, followed up with optical light observations while the prompt phase was still active.

MASTER-IAC gathered critical data on the proportion of polarized optical light relative to the total light produced by the prompt phase. Because synchrotron radiation is one of only a limited number of phenomena that can create polarized light, these data provided the crucial link between synchrotron radiation and the prompt phase of GRB160625B.

A magnetic field can also influence how much polarized light is emitted as time passes and the burst evolves. Because the researchers were able to analyze polarization data that spanned nearly the entire timeframe of the burst — a rare achievement — they were able to discern the presence of a magnetic field and track how it changed as GRB160625B progressed.

“There is very little data on polarized emission from gamma-ray bursts,” said Kutyrev, who is also an associate scientist at NASA’s Goddard Space Flight Center. “This burst was unique because we caught the polarization state at an early stage. This is hard to do because it requires a very fast reaction time and there are relatively few telescopes with this capability. This paper shows how much can be done, but to get results like this consistently, we will need new rapid-response facilities for observing gamma-ray bursts.”

Dawn Of The Cosmos: Seeing Galaxies That Appeared Soon After The Big Bang

Arizona State University astronomers Sangeeta Malhotra and James Rhoads, working with international teams in Chile and China, have discovered 23 young galaxies, seen as they were 800 million years after the Big Bang. The results from this sample have been recently published in the Astrophysical Journal.

Long ago, about 300,000 years after the beginning of the universe (the Big Bang), the universe was dark. There were no stars or galaxies, and the universe was filled with neutral hydrogen gas. In the next half billion years or so the first galaxies and stars appeared. Their energetic radiation ionized their surroundings, illuminating and transforming the universe.

This dramatic transformation, known as re-ionization, occurred sometime in the interval between 300 million years and one billion years after the Big Bang. Astronomers are trying to pinpoint this milestone more precisely and the galaxies found in this study help in this determination.

“Before re-ionization, these galaxies were very hard to see, because their light is scattered by gas between galaxies, like a car’s headlights in fog,” says Malhotra. “As enough galaxies turn on and ‘burn off the fog’ they become easier to see. By doing so, they help provide a diagnostic to see how much of the ‘fog’ remains at any time in the early universe.”

The Dark Energy Camera

To detect these galaxies, Malhotra and Rhoads have been using the Dark Energy Camera (DECam), one of the new powerful instruments in the astronomy field. DECam is installed at the National Optical Astronomy Observatory (NOAO)’s 4-meter Blanco Telescope, located at the Cerro Tololo Inter-American Observatory (CTIO), in northern Chile, at an altitude of 7,200 feet.

“Several years ago, we carried out a similar study using a 64-megapixel camera that covers the same amount of sky as the full moon,” says Rhoads. “DECam, by comparison, is a 570-megapixel camera and covers 15 times the area of the full moon in a single image.”

DECam was recently made even more powerful when it was equipped with a special narrowband filter, designed at ASU’s School of Earth and Space Exploration (SESE), primarily by Rhoads and Zheng (who was a SESE postdoctoral fellow and is currently at the Shanghai Astronomical Observatory in China), with assistance from Alistair Walker of NOAO.

“We spent several months refining the design of the filter profile, optimizing the design to get maximum sensitivity in our search” says Zheng, the lead author of this study.

Touching the Cosmic Dawn

The galaxy search using the ASU-designed filter and DECam is part of the ongoing “Lyman Alpha Galaxies in the Epoch of Reionization” project (LAGER). It is the largest uniformly selected sample that goes far enough back in the history of the universe to reach cosmic dawn.

“The combination of large survey size and sensitivity of this survey enables us to study galaxies that are common but faint, as well as those that are bright but rare, at this early stage in the universe,” says Malhotra.

Junxian Wang, a co-author on this study and the lead of the Chinese LAGER team, adds that “our findings in this survey imply that a large fraction of the first galaxies that ionized and illuminated the universe formed early, less than 800 million years after the Big Bang.”

The next steps for the team will be to build on these results. They plan to continue to search for distant star forming galaxies over a larger volume of the universe and to further investigate the nature of some of the first galaxies in the universe.

‘Strong’ 6.1-Magnitude Earthquake Strikes Off Japan Coast

An earthquake of magnitude 6.1 struck in the Pacific Ocean, off the coast of Japan, this morning.

The shaker – which is classed as “strong” – was near the island of Okinawa, which has a population of more than 1.4million.

Almost 16,000 people were killed by an earthquake off Japan’s coast in 2011.

The under-sea tremor – which has a similar depth to today’s quake – caused a tsunami, which led to the Fukushima Daiichi nuclear disaster.

The epicentre was in the Pacific Ocean – between Japan, China, South Korea and the Philippines, which has a population of 100million.

The island of Taiwan – where 24million people live – is very near.

There were no immediate reports of damage or injuries in the quake, which hit at a depth of 21 miles, about 166 miles east of Okinawa.

The US Geological Survey – which monitors earthquakes and volcanoes worldwide – said there is a “low likelihood” of casualties and damage.
There is a one in three chance up to 10 people could be killed – and only a 4% chance of more deaths.

The 1.4million people who leave nearby will have felt “weak” effects.

A USGS spokesman said: “Overall, the population in this region resides in structures that are resistant to earthquake shaking – though vulnerable structures exist.

“The predominant vulnerable building types are low-rise concrete wall and light wood frame construction.”

Japan lies on the notorious “Ring of Fire” – land around the Pacific Ocean regularly rocked by earthquakes and volcanoes.

A powerful 6.6-magnitude earthquake struck Indonesia – also in the region – back in May.

Two people were killed and more than 120 injured when an earthquake hit the Mediterranean last week.

A series of earthquakes in Wyoming has sparked fears a giant supervolcano in Yellowstone National Park could blow.

Cosmologists Produce New Maps Of Dark Matter Dynamics

New maps of dark matter dynamics in the Universe have been produced by a team of international cosmologists.

Using advanced computer modelling techniques, the research team has translated the distribution of galaxies into detailed maps of matter streams and velocities for the first time.

The research was carried out by leading cosmologists from the UK, France and Germany.

Dr Florent Leclercq from the University of Portsmouth’s Institute of Cosmology and Gravitation said: “Dark matter is a substance of yet unknown nature that scientists believe makes up more than 80 per cent of the total mass of the Universe. As it does not emit or react to light, its distribution and evolution are not directly observable and have to be inferred.”

The researchers used legacy survey data obtained during 2000 — 2008 from the Sloan Digital Sky Survey (SDSS), a major three-dimensional survey of the Universe. The survey has deep multi-colour images of one fifth of the sky and spectra for more than 900,000 galaxies. The new dark matter maps cover the Northern Sky up to a distance of 600 megaparsecs, which is the equivalent of looking back about two billion years.

The researchers used a set of phase-space analysis tools and built on research from 2015, which reconstructed the initial conditions of the nearby Universe.

Dr Leclercq said: “Adopting a phase-space approach discloses a wealth of information, which was previously only analysed in simulations and thought to be inaccessible using observations.

“Accessing this information in galaxy surveys opens up new ways of assessing the validity of theoretical models in light of observations.”

The research is published in the Journal of Cosmology and Astroparticle Physics.