Monster Colliding Black Holes Might Lurk On The Edge Of Spiral Galaxies

The outskirts of spiral galaxies like our own could be crowded with colliding black holes of massive proportions and a prime location for scientists hunting the sources of gravitational waves, said researchers at Rochester Institute of Technology in an upcoming paper in Astrophysical Journal Letters.

The RIT study identifies an overlooked region that may prove to be rife with orbiting black holes and the origin of gravitational-wave chirps heard by observatories in the United States and Italy. Identifying the host galaxies of merging massive black holes could help explain how orbiting pairs of black holes form.

Conditions favorable for black-hole mergers exist in the outer gas disks of big spiral galaxies, according to Sukanya Chakrabarti, assistant professor of physics at RIT and lead author of “The Contribution of Outer HI Disks to the Merging Binary Black Hole Populations.”

Until now, small satellite or dwarf galaxies were thought to have the most suitable environment for hosting black-hole populations: a sparse population of stars, unpolluted with heavy metals like iron, gold and platinum — elements spewed in supernovae explosions — and inefficient winds that leave massive stars intact.

Chakrabarti realized the edges of galaxies like the Milky Wavy have similar environments to dwarf galaxies but with a major advantage — big galaxies are easier to find.

“The metal content in the outer disks of spiral galaxies is also quite low and should be rife with black holes in this large area,” Chakrabarti said.

A co-author on the paper, Richard O’Shaughnessy, assistant professor of mathematical sciences at RIT and a member of the LIGO Scientific Collaboration, said: “This study shows that, when predicting or interpreting observations of black holes, we need to account not only for differences between different types of galaxies but also the range of environments that occur inside of them.”

A deeper understanding of the universe is possible now that scientists can combine gravitational wave astronomy with traditional measurements of bands of light. Existing research shows that even black holes, which are too dense for light to escape, have a gravitational wave and an optical counterpart, remnants of matter from the stellar collapse from which they formed.

“If you can see the light from a black-hole merger, you can pinpoint where it is in the sky,” Chakrabarti said. “Then you can infer the parameters that drive the life cycle of the universe as a whole and that’s the holy grail for cosmology. The reason this is important is because gravitational waves give you a completely independent way of doing it so it doesn’t rely on astrophysical approximations.”

‘Monster’ Planet Discovery Challenges Formation Theory

A giant planet, which should not exist according to planet formation theory, has been discovered around a distant star. The new research is presented in a paper recently accepted for publication in the journal Monthly Notices of the Royal Astronomical Society.

The existence of the ‘monster’ planet, ‘NGTS-1b’, challenges theories of planet formation which state that a planet of this size could not be formed around such a small star. According to these theories, small stars can readily form rocky planets but do not gather enough material together to form Jupiter-sized planets.

‘NGTS-1b’ however, is a ‘gas giant’ — due to its size and temperature, the planet is known as a ‘hot Jupiter’, a class of planets that are at least as large as our solar system’s very own Jupiter, but with around 20% less mass. Unlike Jupiter however, NGTS-1b is very close to its star — just 3% of the distance between Earth and the Sun, and completes an orbit every 2.6 days, meaning a year on NGTS-1b lasts two and a half Earth-days.

In contrast, the host star is small, with a radius and mass half that of our sun. Professor Peter Wheatley from the University of Warwick commented on the complications this introduced: “Despite being a monster of a planet, NGTS-1b was difficult to find because its parent star is so small and faint.” He went on to explain the significance of the discovery given the challenging circumstances “small stars like this red M-dwarf are actually the most common in the Universe, so it is possible that there are many of these giant planets waiting to found.”

NGTS-1b is the first planet to be spotted by The Next-Generation Transit Survey (or ‘NGTS’) which employs an array of 12 telescopes to scour the sky. The researchers made their discovery by continually monitoring patches of the night sky over many months, and detecting red light from the star with innovative red-sensitive cameras. They noticed dips in the light from the star every 2.6 days, implying that a planet was orbiting and periodically blocking the starlight.

Using these data, they then tracked the planet’s orbit and calculated the size, position and mass of NGTS-1b by measuring the radial velocity of the star. In fact, this method, measuring how much the star ‘wobbles’ due to the gravitational tug from the planet, was the best way of measuring NGTS-1b’s size.

Dr Daniel Bayliss, lead author of the study, also from the University of Warwick, commented “The discovery of NGTS-1b was a complete surprise to us — such massive planets were not thought to exist around such small stars — importantly, our challenge now is to find out how common these types of planets are in the Galaxy, and with the new Next-Generation Transit Survey facility we are well-placed to do just that.”

NGTS is situated at the European Southern Observatory’s Paranal Observatory in the heart of the Atacama Desert, Chile, but is one of very few facilities to be run by external parties — UK Universities Warwick, Leicester, Cambridge, and Queen’s University Belfast are involved, together with Observatoire de Genève, DLR Berlin and Universidad de Chile.

Professor Peter Wheatley leads NGTS, and was pleased to see these exciting results: “Having worked for almost a decade to develop the NGTS telescope array, it is thrilling to see it picking out new and unexpected types of planets. I’m looking forward to seeing what other kinds of exciting new planets we can turn up.”

New Greenland Maps Show More Glaciers At Risk

New maps of Greenland’s coastal seafloor and bedrock beneath its massive ice sheet show that two to four times as many coastal glaciers are at risk of accelerated melting as had previously been thought.

Researchers at the University of California, Irvine, NASA and 30 other institutions have published the most comprehensive, accurate and high-resolution relief maps ever made of Greenland’s bedrock and coastal seafloor. Among the many data sources incorporated into the new maps is data from NASA’s Ocean Melting Greenland campaign.

Lead author Mathieu Morlighem of UCI had demonstrated in an earlier study that data from OMG’s survey of the shape and depth, or bathymetry, of the seafloor in Greenland’s fjords improved scientists’ understanding of both the coastline and the inland bedrock beneath glaciers that flow into the ocean. That’s because the bathymetry at a glacier’s front limits the possibilities for the shape of bedrock farther upstream.

The nearer to the shoreline, the more valuable the bathymetry data are for understanding on-shore topography, Morlighem said. “What made OMG unique compared to other campaigns is that they got right into the fjords, as close as possible to the glacier fronts. That’s a big help for bedrock mapping,” he added.

Additionally, the OMG campaign surveyed large sections of the Greenland coast for the first time ever. In fjords for which there are no data, it’s difficult to estimate how deep the glaciers extend below sea level.

The OMG data are only one of many datasets Morlighem and his team used in the ice sheet mapper, which is named BedMachine. Another comprehensive source is NASA’s Operation IceBridge airborne surveys. IceBridge measures the ice sheet thickness directly along a plane’s flight path. This creates a set of long, narrow strips of data rather than a complete map of the ice sheet.

Besides NASA, almost 40 other international collaborators also contributed various types of survey data on different parts of Greenland.

No survey, not even OMG, covers every glacier on Greenland’s long, convoluted coastline. To infer the bed topography in sparsely studied areas, BedMachine averages between existing data points using physical principles such as the conservation of mass.

The new maps reveal that two to four times more oceanfront glaciers extend deeper than 600 feet (200 meters) below sea level than earlier maps showed. That’s bad news, because the top 600 feet of water around Greenland comes from the Arctic and is relatively cold. The water below it comes from farther south and is 6 to 8 eight degrees Fahrenheit (3 to 4 degrees Celsius) warmer than the water above. Deeper-seated glaciers are exposed to this warmer water, which melts them more rapidly.

Morlighem’s team used the maps to refine their estimate of Greenland’s total volume of ice and its potential to add to global sea level rise if the ice were to melt completely, which is not expected to occur within the next few hundred years. The new estimate is higher by 2.76 inches (7 centimeters) for a total of 24.34 feet (7.42 meters).

OMG principal investigator Josh Willis of JPL, who was not involved in producing the maps, said, “These results suggest that Greenland’s ice is more threatened by changing climate than we had anticipated.”

On Oct. 23, the five-year OMG campaign completed its second annual set of airborne surveys to measure for the first time the amount that warm water around the island is contributing to the loss of the Greenland ice sheet. Besides the one-time bathymetry survey, OMG is collecting annual measurements of the changing height of the ice sheet and the ocean temperature and salinity in more than 200 fjord locations. Morlighem looks forward to improving BedMachine’s maps with data from the airborne surveys.

The maps and related research are in a paper titled “BedMachine v3: Complete bed topography and ocean bathymetry mapping of Greenland from multi-beam echo sounding combined with mass conservation” in Geophysical Research Letters. This project received support from NASA’s Cryospheric Sciences Program and the National Science Foundation’s ARCSS program.

How Life Arose From Primordial Muck: Experimental Evidence Overturns Accepted Theory

Life on Earth originated in an intimate partnership between the nucleic acids (genetic instructions for all organisms) and small proteins called peptides, according to two new papers from biochemists and biologists at the University of North Carolina at Chapel Hill and the University of Auckland. Their “peptide-RNA” hypothesis contradicts the widely-held “RNA-world” hypothesis, which states that life originated from nucleic acids and only later evolved to include proteins.

The new papers — one in Molecular Biology and Evolution, the other in Biosystems — show how recent experimental studies of two enzyme superfamilies surmount the tough theoretical questions about how complex life emerged on Earth more than four billion years ago.

“Until now, it has been thought to be impossible to conduct experiments to penetrate the origins of genetics,” said co-author Charles Carter, PhD, professor of biochemistry and biophysics at the UNC School of Medicine. “But we have now shown that experimental results mesh beautifully with the ‘peptide-RNA’ theory, and so these experiments provide quite compelling answers to what happened at the beginning of life on Earth.”

The special attributes of the ancestral versions of these enzyme superfamlies, and the self-reinforcing feedback system they would have formed with the first genes and proteins, would have kick-started early biology and driven the first life forms toward greater diversity and complexity, the researchers said.

Co-author Peter Wills, PhD, professor of physics at the University of Auckland, said, “Compared to the RNA-world hypothesis, what we’ve outlined is simply a much more probable scenario for the origin of life. We hope our data and the theory we’ve outlined in these papers will stimulate discussion and further research on questions relevant to the origins of life.”

The two scientists are fully aware that the RNA-world hypothesis still dominates the origin-of-life research field. “That theory is so alluring and expedient that most people just don’t think there’s any alternative,” Carter said. “But we are very confident there is.”

Before there was life on Earth, there were simple chemicals. Somehow, they produced both amino acids and nucleotides that eventually became the proteins and nucleic acids necessary to create single cells. And the single cells became plants and animals. Research this century has revealed how the primordial chemical soup created the building blocks of life. There is also widespread scientific consensus on the historical path by which cells evolved into plants and animals.

But it’s still a mystery how the amino acid building blocks were first assembled according to coded nucleic acid templates into the proteins that formed the machinery of all cells.

The widely accepted RNA-world theory posits that RNA — the molecule that today plays roles in coding, regulating, and expressing genes — elevated itself from the primordial soup of amino acids and cosmic chemicals, eventually to give rise first to short proteins called peptides and then to single-celled organisms.

Carter and Wills argue that RNA could not kick-start this process alone because it lacks a property they call “reflexivity.” It cannot enforce the rules by which it is made. RNA needed peptides to form the reflexive feedback loop necessary to lead eventually to life forms.

At the heart of the peptide-RNA theory are enzymes so ancient and important that their remnants are still found in all living cells and even in some sub-cellular structures, including mitochondria and viruses. There are 20 of these ancient enzymes called aminoacyl-tRNA synthetases (aaRSs).

Each of them recognizes one of the 20 amino acids that serve as the building blocks of proteins. (Proteins, considered the machines of life, catalyze and synchronize the chemical reactions inside cells.) In modern organisms, an aaRS effectively links its assigned amino acid to an RNA string containing three nucleotides complementary to a similar string in the transcribed gene. The aaRSs thus play a central role in converting genes into proteins, a process called translation that is essential for all life forms.

The 20 aaRS enzymes belong to two structurally distinct families, each with 10 aaRSs. Carter’s recent experimental studies showed that the two small enzyme ancestors of these two families were encoded by opposite, complementary strands of the same small gene. The simplicity of this arrangement, with its initial binary code of just two kinds of amino acids, suggests it occurred at the very dawn of biology. Moreover, the tight, yin-yang interdependence of these two related but highly distinct enzymes would have stabilized early biology in a way that made inevitable the orderly diversification of life that followed.

“These interdependent peptides and the nucleic acids encoding them would have been able to assist each other’s molecular self-organization despite the continual random disruptions that beset all molecular processes,” Carter said. “We believe that this is what gave rise to a peptide-RNA world early in Earth’s history,” Carter said.

Related research by Carter and UNC colleague Richard Wolfenden, PhD, previously revealed how the intimate chemistries of amino acids enabled the first aaRS enzymes to fold properly into functional enzymes, while simultaneously determining the assignments in the universal genetic coding table.

“The enforcement of the relationship between genes and amino acids depends on aaRSs, which are themselves encoded by genes and made of amino acids,” Wills said. “The aaRSs, in turn, depend on that same relationship. There is a basic reflexivity at work here. Theorist Douglas Hofstadter called it a ‘strange loop.’ We propose that this, too, played a crucial role in the self-organization of biology when life began on Earth. Hofstadter argued that reflexivity furnishes the force driving the growth of complexity.”

Carter and Wills developed two additional reasons why a pure RNA biology of any significance was unlikely to have predated a peptide-RNA biology. One reason is catalysis — the acceleration of chemical reactions involving other molecules.

Catalysis is a key feature of biology that RNA cannot perform with much versatility. In particular, RNA enzymes cannot readily adjust their activities to temperature changes likely to have happened as the earth cooled, and so cannot perform the very broad range of catalytic accelerations that would have been necessary to synchronize the biochemistry of early cell-based life forms. Only peptide or protein enzymes have that kind of catalytic versatility, Carter said.

Secondly, Wills has shown that impossible obstacles would have blocked any transition from a pure-RNA world to a protein-RNA world and onward toward life.

“Such a rise from RNA to cell-based life would have required an out-of-the-blue appearance of an aaRS-like protein that worked even better than its adapted RNA counterpart,” Carter said. “That extremely unlikely event would have needed to happen not just once but multiple times — once for every amino acid in the existing gene-protein code. It just doesn’t make sense.”

Thus, because the new Carter-Wills theory actually addresses real problems of the origin of life that are concealed by the expediency of the RNA-world hypothesis, it is actually a far simpler account of how things probably happened just before life on Earth rose from the primordial soup.

The National Institute of General Medical Sciences and the John Templeton Foundation funded the research.

Pacific Rim Earthquake Fears: Huge Seismic Swarm Hits Off The Coast Of Australia

The Pacific Ring of Fire has been peppered with earthquakes over the past 24 hours with the region surrounding Australia particularly active.

A swarm of seven earthquakes measuring between 4.5 and 5.1 on the Richter Scale struck a small area in the Coral Sea near New Caledonia.

Two measuring 4.7 and 4.9 hit Indonesia, to the north of Australia, with another measuring 4.4 struck Fiji.

Across other parts of the Pacific Rim, three earthquakes hit near Guam, one struck Japan and two were recorded in Alaska.

One earthquake was also struck on the west coast of America, one in Mexico and a final in Argentina – all over the past day.

It increases fears ‘the Big One’ could be about to strike the Pacific Ring of Fire – although, as with all geological events, it is impossible to predict exactly when or where this will occur.

However, geologists claim new research which they say show it is now possible to get a “five-years heads-up” on future earthquakes.

The team at the University of Colorado and the University of Montana claim fluctuations in the Earth’s core may be linked to an increased in the number of earthquakes with magnitudes of 7.0 or higher.

Roger Bilham of the University of Colorado said: “The Earth offers us a 5-years heads up on future earthquakes, which is remarkable.

“Calculations show the asthenosphere to have an appropriate viscosity to account for the delay between deceleration and subduction zone seismicity.

“However, a geodetic test of the anticipated westward overshoot would be of utility.

“Whatever the mechanism, the 5-6 year advanced warning of increased seismic hazards afforded by the first derivative of the LoD is fortuitous, and has utility in disaster planning.

“The year 2017 marks six years following a deceleration episode that commenced in 2011.

“This suggests the world has now entered a period of enhanced global seismic productivity with a duration of at least five years.”

Study Of W Hydrae Suggests Condensed Aluminum Oxide Dust Plays Key Role In Accelerating Stellar Wind

A team of researchers affiliated with several institutions in Japan has found evidence showing that condensed aluminum oxide dust surrounding the star W Hydrae plays a key role in accelerating the stellar wind. In their paper published on the open access site Science Advances, the team describes their study of the star and the gases that surround it.

As scientists look to the stars to understand the nature of the universe, they also seek answers regarding universal origins. The Big Bang, theory, for example, suggests how things might have started, but what processes led to the creation of atoms, for example? In this new effort, the researchers believe they may have found a source: W Hydrae, a star that is part of the Hydrae constellation and is classified as an asymptotic giant branch (AGB) star—stars that are still evolving and are in the low to medium mass size. W Hydrae has approximately nine times the mass of our sun and is a popular object of study due to its brightness. Scientists have come to believe that the study of AGBs might offer clues regarding how the elements were created.

Using the Atacama Large Millimeter/submillimeter Array of telescopes, the researchers observed W Hydrae, one of the brightest stars as seen from Earth. The researchers found evidence of aluminum oxide dust in its outer shell—within three “stellar radii.” The presence of the dust, the researchers suggest, might be a driver of stellar wind and perhaps a means of synthesizing atoms. In their theory, the aluminum oxide grows into grains and aggregates in the dust shell. The aggregates move more when struck by light from the star. As they move away from the star, they encounter silicate dust and continue to move away from the star, causing the stellar wind (the continues flow of charged particles emitted from the star) to pick up. As part of this process, atoms such as silicon and oxygen may be formed. They also suggest the process prevents silicate dust from forming efficiently around the star.