On October 12th delegates attending the Royal Astronomical Society (RAS) meeting ‘Early Solar System Processes on Meteorites’ will discuss the competing theories. The meeting is being held in honour of the late Robert Hutchison, who was a distinguished meteorite expert at the Natural History Museum and used early Solar System samples to deduce how asteroids formed.
One group of scientists believes that the partial melting of asteroids led to the formation of chondrules, mm-size melt droplets which make up many meteorites. Another camp is convinced that asteroids grew from cold particles in the solar nebula and that the chondrules formed beforehand. There are currently two main ways of studying this question: one is to analyse the composition and age of primitive meteorites, the other makes use of similarly primitive grains collected from Comet Wild-2 by the NASA Stardust space probe, which returned a sample to Earth in January 2006.
Like other comets, Wild-2 began life in the earliest stages of the Solar System, more than 4500 million years ago. At that time the rocky, metallic and icy material that ultimately formed the planets started to form larger bodies. Ices of water, ammonia, carbon dioxide and carbon monoxide condensed in the cold outer parts of the Solar System. Most of the ices ended up as part of the gas giant planets – Jupiter, Saturn, Uranus and Neptune – but some remained in much smaller bodies 1-10 km across that eventually formed the cores (nuclei) of comets.
Comets that have spent most of their lives at a great distance from the Sun contain the least processed material in the Solar System, whereas in contrast an increasing number of scientists believe that asteroid surfaces were extensively melted. For example, one theory put forward by Dr Ian Sanders of Trinity College Dublin is that the presence of radioactive material created enough heat to partially melt the building blocks of planets and asteroids (planetesimals) found in the early Solar System. When these objects collided they would have created great clouds of molten droplets, the predecessors of the material found in asteroids today.
Meeting chair Dr John Bridges of the University of Leicester is part of the international team studying grains from Wild-2 and hence the early history of the Solar System. Dr Bridges comments ‘There has been a vigorous debate for many years about how the earliest planetesimals formed – either from cold accumulation of dust and gas from the nebula and interstellar space or through impact and radioactivity-induced melting. By studying Comet Wild-2 and primitive meteorites we are starting to reveal the true nature of a violent early Solar System where many of the earliest planetary building blocks underwent repeated collisions and melting episodes.’
Robert Massey | alfa
Save the date: Forum European Neuroscience – 07-11 July 2018 in Berlin, Germany
02.05.2018 | FENS - Federation of European Neuroscience Societies
Invitation to the upcoming "Current Topics in Bioinformatics: Big Data in Genomics and Medicine"
13.04.2018 | Max-Planck-Institut für molekulare Genetik
So-called quantum many-body scars allow quantum systems to stay out of equilibrium much longer, explaining experiment | Study published in Nature Physics
Recently, researchers from Harvard and MIT succeeded in trapping a record 53 atoms and individually controlling their quantum state, realizing what is called a...
The historic first detection of gravitational waves from colliding black holes far outside our galaxy opened a new window to understanding the universe. A...
A team led by Austrian experimental physicist Rainer Blatt has succeeded in characterizing the quantum entanglement of two spatially separated atoms by observing their light emission. This fundamental demonstration could lead to the development of highly sensitive optical gradiometers for the precise measurement of the gravitational field or the earth's magnetic field.
The age of quantum technology has long been heralded. Decades of research into the quantum world have led to the development of methods that make it possible...
Cardiovascular tissue engineering aims to treat heart disease with prostheses that grow and regenerate. Now, researchers from the University of Zurich, the Technical University Eindhoven and the Charité Berlin have successfully implanted regenerative heart valves, designed with the aid of computer simulations, into sheep for the first time.
Producing living tissue or organs based on human cells is one of the main research fields in regenerative medicine. Tissue engineering, which involves growing...
A team of scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg investigated optically-induced superconductivity in the alkali-doped fulleride K3C60under high external pressures. This study allowed, on one hand, to uniquely assess the nature of the transient state as a superconducting phase. In addition, it unveiled the possibility to induce superconductivity in K3C60 at temperatures far above the -170 degrees Celsius hypothesized previously, and rather all the way to room temperature. The paper by Cantaluppi et al has been published in Nature Physics.
Unlike ordinary metals, superconductors have the unique capability of transporting electrical currents without any loss. Nowadays, their technological...
02.05.2018 | Event News
13.04.2018 | Event News
12.04.2018 | Event News
18.05.2018 | Power and Electrical Engineering
18.05.2018 | Information Technology
18.05.2018 | Information Technology