Lifeboat Foundation

Star clusters are interesting inhabitants of the sky. They vary in sizes, distances, and number of stars, but almost all are spectacular to look at. And most of them are in the process of being torn apart. That is certainly the case for the Hyades star cluster – the closest one to Earth at only 153 light years away. The problem is, there is something causing a lot more destruction than would be expected given the mass and energy in the surrounding space. Now, a team of scientists from ESA have a theory as to what the cause of the destruction might be – a mysterious dark matter sub-halo.

This novel theory extends from findings gleaned from data collected by GAIA, ESA’s star mapping satellite. The GAIA team expected to see what are called “tidal tails” trailing and leading the star cluster as it moves throughout the galaxy. These tails are formed when some stars are forced to the outer edges of the cluster, and then pulled by the gravitational pull of the galaxy itself, pushing some stars forward in their journey through the galaxy, while other stars are pulled further behind.

The GAIA team did find tidal tails on either side of the Hyades cluster when they observed it. However, they were extraordinarily long – thousands of light years across the galaxy, each holding thousands of stars. Observing them in their entirety was only possible because of the GAIA data and a computer model that Dr. Tereza Jerabkova, an ESA research fellow, developed with her colleagues.

A pair of researchers with Indiana University and Illinois University, respectively, has developed a theory that suggests crystalizing uranium “snowflakes” deep inside white dwarfs could instigate an explosion large enough to destroy the star. In their paper published in the journal Physical Review Letters, C. J. Horowitz and M. E. Caplan describe their theory and what it could mean to astrophysical theories about white dwarfs and supernovas.

White dwarfs are small stars that have burned up most of their nuclear fuel—they are typically much cooler than they once were and are very dense. In this new effort, Horowitz and Caplan used data from the Gaia space observatory to theorize that sometimes small grains of uranium could begin to crystalize (due to enriched actinides), forming what they describe as snowflakes. They suggest this could happen because of the differing melting points of the material involved. They further suggest that if this were to occur, it could lead to splitting of atomic nuclei, resulting in a series of fission reactions as the solids become enriched in actinides. And if such reactions were to raise the temperature of the interior of the star by igniting carbon, the result would likely be merging of atomic nuclei and eventually a very large fusion reaction that would result in a large explosion—likely large enough to destroy the star.

Scientists have reported the discovery of a rare, medium-sized black hole that may help answer one of the more tantalizing questions in astronomy: how do their supermassive counterparts come into being?

There are two well-known sizes of black hole — at one end, so-called stellar-class ones which are typically three to ten times the mass of our Sun — and at the other, supermassive ones, found at the center of most galaxies, including the Milky Way, which are millions to billions times heavier.

The newly detected ‘goldilocks’ black hole — about 55000 solar masses — could be a missing link between these two extremes, scientists suggested Monday in the journal Nature Astronomy.

The story of particle mass starts right after the big bang. During the very first moments of the universe, almost all particles were massless, traveling at the speed of light in a very hot “primordial soup.” At some point during this period, the Higgs field turned on, permeating the universe and giving mass to the elementary particles.

The Higgs field changed the environment when it was turned on, altering the way that particles behave. Some of the most common metaphors compare the Higgs field to a vat of molasses or thick syrup, which slows some particles as they travel through.

Others have envisioned the Higgs field as a crowd at a party or a horde of paparazzi. As famous scientists or A-list celebrities pass through, people surround them, slowing them down, but less-known faces travel through the crowds unnoticed. In these cases, popularity is synonymous with mass—the more popular you are, the more you will interact with the crowd, and the more “massive” you will be.

The center of the Milky Way is mysteriously glowing.

Sure, there’s a whole bunch of stars there, along with a black hole 4 million times the mass of the Sun — but subtract the light from all that, and we’re still left with this mysterious excess gamma radiation that suffuses the region.

It’s called the Galactic Center GeV Excess (GCE), and it’s puzzled scientists since its discovery by physicists Lisa Goodenough and Dan Hooper in 2009. In data from NASA’s Fermi telescope, they found excess gamma radiation — some of the most energetic light in the Universe — and we haven’t been able to directly detect whatever is causing it.

Circa 2000 o.o 100000 times hotter than the sun quark gluon plasma is.quite interesting.

The European Laboratory for Particle Physics (CERN) plans to announce today (10 February) that it has “compelling evidence” that its scientists have created the quark–gluon state of matter predicted to have existed shortly after the Big Bang.

If confirmed, this would be the first time that conditions within the first three minutes after the Big Bang — the point at which the protons and neutrons that make up atomic nuclei came into being — have been observed under experimental conditions.

Continue reading “CERN claims first experimental creation of quark–gluon plasma” »

The very first moments of the Universe can be reconstructed mathematically even though they cannot be observed directly. Physicists from the Universities of Göttingen and Auckland (New Zealand) have greatly improved the ability of complex computer simulations to describe this early epoch. They discovered that a complex network of structures can form in the first trillionth of a second after the Big Bang. The behavior of these objects mimics the distribution of galaxies in today’s Universe. In contrast to today, however, these primordial structures are microscopically small. Typical clumps have masses of only a few grams and fit into volumes much smaller than present-day elementary particles. The results of the study have been published in the journal Physical Review D.

MIT Haystack Observatory is one of the 13 stakeholder institutions that constitute the Event Horizon Telescope (EHT) collaboration, which produced the first-ever image of a black hole. The EHT revealed today a new view of the massive object at the center of the M87 galaxy: how it looks in polarized light. This is the first time astronomers have been able to measure polarization, a signature of magnetic fields, this close to the edge of a black hole. The observations are key to explaining how the M87 galaxy, located 55 million light-years away, is able to launch energetic jets from its core.

Haystack Research Scientist Vincent Fish says “Hundreds of people around the world in the EHT collaboration, including scientists and engineers at Haystack, have worked very hard to investigate the role of magnetic fields in shaping jets around black holes. Can magnetic fields build up and dominate over the intense pull of gravity? Our data provide an answer.”

Data from ESA’s Gaia star mapping satellite have revealed tantalizing evidence that the nearest star cluster to the Sun is being disrupted by the gravitational influence of a massive but unseen structure in our galaxy.

If true, this might provide evidence for a suspected population of ‘dark matter sub-halos’. These invisible clouds of particles are thought to be relics from the formation of the Milky Way, and are now spread across the galaxy, making up an invisible substructure that exerts a noticeable gravitational influence on anything that drifts too close.

Continue reading “Tantalizing Evidence: Is the Nearest Star Cluster to the Sun Being Destroyed?” »