Most large celestial objects are found to be approximately spherical in shape, e.g. moons, planets and stars. This is because the cause and the dominating force in cosmic structure formation is gravity: a force which pulls mass in all directions equally. Another sphere is the celestial sphere – the heavens above us upon which we observe astronomical observations. This means that data collected on planetary surfaces or observed on in the sky live natively on the sphere.
Hello! My name is Ashley Stock and this summer I had the privilege of being a summer student at MSSL, under the supervision of Prof. Kinwah Wu. I investigated the motions of massless particles (photons) in close proximity to non-rotating (Schwarzschild) and rotating (Kerr) black holes.
At the end of June, we had the opportunity to work at MSSL with Dr. Ignacio Ferreras for one week. As college (high school) students interested in pursuing careers in science and/or engineering, this was the perfect opportunity for us to not only get a taste of what research is like at the frontiers of science, but also to experience in first person the daily life of a scientist.
Galaxies are not simply conglomerations of stars, gas and dust. They are the building blocks of the Universe, the ultimate energy factories and at least one of them is home to intelligent life. In fact, besides the Big Bang, the origin of most electromagnetic radiation in the Universe can be traced back to galaxies. Nonetheless, the existence of supermassive black holes in galaxy centres, although now well-established, is still puzzling scientists. How did these mysterious objects come to be? When did they first form? Is there one in the centre of every galaxy? More puzzling yet, is the idea that they can regulate the formation of stars in the galaxies in which they reside.
The Swift satellite, part of which was built at the Mullard Space Science Laboratory, detected the remarkable Gamma-ray Burst (GRB) 130427A about 3 years ago. This burst has the highest fluence (energy divided by surface) of the over 1000 events detected by Swift and indeed by any space observatory for 30 years.
Neutrons stars are one of the final stages of the stellar evolution of a massive star, in which a compact object made mostly of neutrons is left after a supernova event. With masses ~ 1.5 M☉ and radii of the order of ~ 10 km, neutron stars have an average density of ~ 1014 – 1015 gr cm-3, which is comparable to the density of an atomic nucleus (~2 . 1014 gr cm-3). Due to their high densities, they have strong surface gravitational fields and quantum effects dominate the properties of matter in their interiors.
Last night (30th March 2016) the flagship BBC documentary show, Horizon, had a programme on dark energy: that mysterious “thing” that is causing the expansion of the Universe to accelerate, and which accounts for approximately 70% of the mass-enemy content of the Universe.
Imagine time running backwards. People would grow younger instead of older and, after a long life of gradual rejuvenation – unlearning everything they know – they would end as a twinkle in their parents’ eyes. That’s time as represented in a novel by science fiction writer Philip K Dick but, surprisingly, time’s direction is also an issue that cosmologists are grappling with.
Cosmic rays are rays of particles and radiation emitted from various astrophysical environments, for instance shocks, Active Galactic Nuclei (AGN), Puslar Wind Nebulae and Supernova Remnants. We can observe these cosmic rays from the Earth, and their spectrum takes on a distinctive power-law shape with a peak at a few GeV (billions of electron volts, eV), and ‘knee’ features around 4 and 400 PeV (1 PeV = 1015 eV = 1 000 000 000 000 000 eV), with an ‘ankle’ at 1 EeV (1 EeV = 1018 eV). The lower energy Cosmic Rays are thought to originate within our galaxy, while higher energy ones come from further afield, providing astronomers with a different way to probe the cosmos, without using conventional observations of electromagnetic radiation.
We live in interesting times. For thousands of years, we have thought we knew what the universe – and everything in it – was made of: normal matter, the kind that make up the elements of the periodic table.
However, the discovery in the 1990s of a completely unknown force dubbed dark energy that makes up 70% of the cosmos – causing it to expand at an accelerated rate – has taught us to be humble. Since then, astronomers have begun investing billions of pounds in experiments which aim to find out what this mysterious phenomenon is. What they discover is guaranteed to change physics forever.