Quantum Tunnelling

Where Does The Mass Of A Proton Come From?

“It is very accurately known how large the average gluon density is inside a proton. What is not known is exactly where the gluons are located inside the proton. We model the gluons as located around the three valance quarks. Then we control the amount of fluctuations represented in the model by setting how large the gluon clouds are, and how far apart they are from each other.”

If you divide the matter we know into progressively smaller and smaller components, you’d find that atomic nuclei, made of protons and neutrons, compose the overwhelming majority of the mass we understand. But if you look inside each nucleon, you find that its constituents – quarks and gluons – account for less than 0.2% of their total mass. The remaining 99.8% must come from the unique binding energy due to the strong force. To understand how that mass comes about, we need to better understand not only the average distribution of sea quarks and gluons within the proton and heavy ions, but to reveal the fluctuations in the fields and particle locations within. The key to that is deep inelastic scattering, and we’re well on our way to uncovering the cosmic truths behind the origin of matter’s mass.

A method to engineer crystals with a large fraction of reactive facets

Versatile superstructures composed of nanoparticles have recently been prepared using various disassembly methods. However, little information is known on how the structural disassembly influences the catalytic performance of the materials. Scientia Professor Rose Amal, Vice-Chancellor’s Research Fellow Hamid Arandiyan and a group from the Particles and Catalysis Research Group from the University of New South Wales (UNSW) School of Chemical Engineering have had their research address this issue published in Nature Communications.

The research team led by Dr Jason Scott and Prof Sean Smith in collaboration with Curtin University and Beijing University of Technology has developed a method that allows them to engineer crystals with a large fraction of reactive facets. An ordered mesostructured La0.6Sr0.4MnO3 (LSMO) perovskite catalyst was disassembled using a unique fragmentation strategy, whereby the newly-exposed (001) reactive faces at each fracture were more reactive towards methane oxidation than the regular (i.e. before disassembly)

It is of significant interest to use methane as an alternative fuel to coal and oil due to its high hydrogen to carbon ratio which provides comparatively lower greenhouse gas emissions. Commercial catalysts for methane combustion contain precious metals (e.g. Pt and Pd) which are of high cost and poor thermal stability (caused by agglomeration of the metal deposits). Using perovskite-type catalysts to replace noble metal supported catalysts for methane oxidation has attracted recent attention due to their excellent thermal stability. In their recently published article, the research team describes a simple fragmentation method to synthesise a novel three-dimensional hexapod mesostructured LSMO perovskite.

Read more.

LIGO scientists detected a third gravitational wave from two colliding black holes.

This week, scientists using the Laser Interferometer Gravitational-Wave Observatory, or LIGO, announced that they had detected another gravitational wave—the third ripple observed since September 2015. The findings were published in the journal Physical Review Letters.

The source of this most recent gravitational wave is a black hole 49 times larger than our sun that was formed by two colliding black holes located 3 billion light-years away. The data indicates that the spin of one or both of the black holes may have a tilted orbit, which can reveal clues to their origins. Theoretical astrophysicist Priyamvada Natarajan explains how this finding sheds light on black hole formation, and how it affects our understanding of general relativity and dark matter. Listen here. 

[Image credit: LIGO/Caltech/MIT/Sonoma State (Aurore Simonnet)]

Photograph of the May 1919 solar eclipse captured by Arthur Eddington, which proved Einstein’s theory of general relativity. 

Credit: SSPL/Getty Images

Galena and Fluorite - Blackdene Mine, Ireshopeburn, Weardale, Co. Durham, England

A movie showing the dynamics of the inner part of the Crab Nebula made using the Chandra X-ray Observatory.

Credit: NASA/CXC/ASU/J.Hester et al.

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David Spriggs, Dark Matter.