The science dispatches for the week ending 03/06/18 collecting the most interesting and important science news for the final week in May including potential signs of intermediate black holes, an exciting breakthrough in artificial nerves, interesting developments in Pluto’s origins and how to own your own Allosaurus.
Tantalising signs of Medium Black holes
When it comes to black holes you may be surprised to learn that it’s not the smallest or the largest that have been of particular interest to cosmologists over the last decade but intermediate mass examples. For years, whilst astronomers have found evidence of black holes ranging from tens to hundreds of solar masses and of supermassive black holes with masses in excess of millions of solar masses, immediate mass black holes (IMBHs) in the range of thousands of solar masses have alluded detection aking them purely hypothetical.
That is until recently.
Now, an international team of astronomers examining an archive of galactic spectra believe that they may have discovered the signature of galaxies containing intermediate black hole candidates. Of the 300 candidate galaxies, they believed to contain these IMBHs, they used cross-referencing with other data sets to confirm that at least 10 “almost certainly” contain the elusive objects the paper published on arVix suggests.
As black holes emit no light it makes them extremely difficult objects for astronomers to detect. The process generally involves the detection of X-ray bursts from the material that forms accretion discs around black holes before being fed into the central object. The extreme pressure and heat in these discs cause the superheating of the constituent gas and dust, which in turn causes the emissions of X-rays. The greater the mass of the central object, the more powerful the X-ray emission, meaning that the faint emissions of IMBHs are understandably more difficult to detect than those of their larger counterparts.
The team led by Igor Chilingarian of the Smithsonian Astrophysical Observatory in Cambridge, Massachusetts examined data from a catalogue of 930,000 galaxy spectra gathered by the Sloan Digital Sky Survey (SDSS), searching for visible light signals rather than X-ray signals. Rotating black holes, otherwise known as Kerr black holes, drag close gas clouds with them at rapid speeds in a phenomena known as frame-dragging, causing a Doppler shift in the frequency of emitted radiation in comparison to slower moving gas clouds further from the black hole. The researchers searched for the tell-tale spectral peaks left by this phenomena finding 305 potential candidates. This was narrowed down to ten by cross-referencing against X-ray emissions detected by NASA’s Chandra and Swift satellites and Europe’s X-ray Multi-Mirror Mission.
The significance of this discovery is the potential to further investigate the process by which supermassive black holes, believed to lie at the centre of most galaxies, formed. The previous lack of detection of IMBHs had led some cosmologists to speculate that SMBHs had formed directly from the collapse of massive gas clouds in the early universe. If this discovery is supported by further research it would suggest a more gradual formation for SMBHs.
Artificial Nerves could Herald a New Era of Prosthetics
Researchers led by chemist Zhenan Bao at Stanford University in Palo Alto, California, announced this week in a Science article dated 31st May, the development of an artificial sensory nerve that works in a similar way to our normal sense of touch. The breakthrough could well bolster an already impressive series of developments in prosthetic limbs which has seen the creation of devices which can be controlled by user’s thoughts and pressure sensitive devices which can simulate a more natural, pressure sensitive grip. The new artificial nerve will improve on this by allowing users to ‘feel’ heat, different types of pressure and changes in position using thousands of sensors.
The nerve made of flexible, organic components consists of three parts; sensors which pick up on various pressure cues by changing the voltage between two electrodes. A ring oscillator which changes this signal into a series of electrical pulses and finally a synaptic transistor, which converts these pulses into a form similar to that produced by neurons. Bao and her team used the system to detect tiny changes in the motion of a small rod travelling across their sensor, to identify various braille characters and to contract a detached cockroach leg.
Artificial nerves should be relatively inexpensive manufacture thus allowing the production of many within the same device. This is not only applicable to artificial limbs but could also be used to develop more sensitive robotics which can better interact with their environment.
Pluto’s Strange Origins and Methane Created Dunes
In a study published in the journal Icarus, researchers from the Southwest Research Institute, a research and development non-profit, led by Christopher Glein have suggested a radical new origin for Pluto. Whilst debate has raged regarding Pluto’s status as a planet or dwarf-planet, many scientists have begun to suggest that it may, in fact, be an extremely large comet. The new research suggests an even more radical possibility; Pluto could be an amalgamation of many comets.
Researchers used data from NASA’s New Horizons spacecraft which performed a fly-by of Pluto in 2015, to estimate the nitrogen content of Pluto and the amount of nitrogen that escaped from its atmosphere. They then crossed referenced this data against composition data of the Comet 67P/Churyumov-Gerasimenko gathered by the European Space Agency’s Rosetta mission which orbited the object for two years before being brought into a controlled collision on its surface in 2016.
A scaling up of Pluto’s nitrogen content produced a model consistent with an object created by the merging of roughly a billion comets or other Kuiper belt objects. Glein explains “We found an intriguing consistency between the estimated amount of nitrogen inside the [Sputnik Planitia] glacier and the amount that would be expected if Pluto was formed by the agglomeration of roughly a billion comets or other Kuiper Belt objects similar in chemical composition to 67P, the comet explored by Rosetta.”
The findings should be viewed with reservations, there still remains the problem of explaining why the carbon monoxide content of Pluto is much lower than would be expected for an amalgamation of comets. Researchers suggest that this excess carbon monoxide may be locked in glaciers or below-surface oceans. Another hindrance lies in the possibility that the composition of 67P/Churyumov-Gerasimenko may not be reflective of the composition of other comets.
In other Pluto news; A study published on 31st May in Science revealed that ridges captured by the above-referenced flyby of Pluto by the New Horizons probe, which resembles wind-sculpted dunes formed on Earth, are most certainly not made of sand.
The dune-like features of the ridges found on the western edge of the Sputnik Planitia were likely caused by the action of ‘sublimation pits’ were solid icy-material is converted to gas via radiation delivered by the Sun and frozen methane grains originating from the near-by Idrisi Montes mountain range. The researchers found that Pluto’s winds were strong enough to create the dun-like features only if the grains being blown were already aloft, with jets of sublimed material likely the only source strong enough to create this condition.
The finding is quite extraordinary given Pluto’s extremely thin atmosphere.
Own an Allosaurus
This week sees the release of the latest chapter in the Jurassic Park cinematic franchise, Jurassic World: Fallen Kingdom. Super-fans could potentially celebrate with a unique piece of merchandise, the fossilised remains of a carnivorous dinosaur, the Allosaurus.
The 154 million-year-old metre-long specimen is being auctioned for a desired price between €1.2 million–1.8 million on June 4th in Paris. The auction is being held to the dismay of palaeontologists who fear the latest example in the growing trend of the auction of such specimens will deny science the opportunity to study what may well be a previously undiscovered species of dinosaur.
The fossil, excavated on private land in Wyoming between 2013 and 2015 shows enough variation in its teeth, skull and pelvis to indicate it is a new species closely related to the Allosaurus, thus making it extremely scientifically significant.
Nature reports that the Society of Vertebrate Paleontology (SVP) in Bethesda, Maryland, which represents more than 2,200 international palaeontologists, has written to Aguttes, the auction house responsible for the sale, urging them to cancel. David Polly, the society’s president, told Nature that the society is concerned about scientifically valuable fossils going into private hands rather than a public repository where scientists can examine and interpret them. “Fossil specimens that are sold into private hands are lost to science,” the letter states. Whilst the auction house hopes the specimen will be passed to a museum or educational institute, they are unwilling to guarantee this.
Paul Barrett, a palaeontologist at the Natural History Museum in London, told Nature that because museums are buying fewer fossils, owing to tighter budgets and the fact that many established museums already have large collections, commercial fossil collectors may now be targeting private buyers. “There seem to be a larger number of wealthy companies and individuals interested in acquiring dinosaurs,” he says.
Palaeontologists are urging the US to establish a law similar to those in China, Argentina and Mongolia which prohibit the export and sale of such specimens.