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Category: cosmology – Page 285

In ‘Flashes of Creation,’ author Paul Halpern tells the story of George Gamow, Fred Hoyle and their decades-long sparring match about the Big Bang.

Flashes of Creation Paul Halpern Basic Books, $30

The Big Bang wasn’t always a sure bet. For several decades in the 20th century, researchers wrestled with interpreting cosmic origins, or if there even was a beginning at all. At the forefront of that debate stood physicists George Gamow and Fred Hoyle: One advocated for an expanding universe that sprouted from a hot, dense state; the other for a cosmos that is eternal and unchanging. Both pioneered contemporary cosmology, laid the groundwork for our understanding of where atoms come from and brought science to the masses.

In Flashes of Creation, physicist Paul Halpern recounts Gamow’s and Hoyle’s interwoven stories. The book bills itself as a “joint biography,” but that is a disservice. While Gamow and Hoyle are the central characters, the book is a meticulously researched history of the Big Bang as an idea: from theoretical predictions in the 1920s, to the discovery of its microwave afterglow in 1,964 and beyond to the realization in the late 1990s that the expansion of the universe is accelerating.

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A new photograph from the Hubble Space Telescope shows a stunning “Einstein Ring” billions of light-years from Earth — a phenomenon named after Albert Einstein, who predicted that gravity could bend light.

The round object at the center of the photograph released by the European Space Agency is actually three galaxies that appear as seven, with four separate images of the most distant of the galaxies forming a visible ring around the others.

The farthest galaxy — a special type of very bright galaxy with a gigantic black hole at its center known as a quasar — is about 15 billion light-years from Earth.

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A ground-breaking detector that aims to use quartz to capture high frequency gravitational waves has been built by researchers at the ARC Centre of Excellence for Dark Matter Particle Physics (CDM) and the University of Western Australia.

In its first 153 days of operation, two events were detected that could, in principle, be , which have not been recorded by scientists before.

Such high frequency gravitational waves may have been created by a primordial black hole or a cloud of dark matter particles.

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At the center of galaxies, like our own Milky Way, lie massive black holes surrounded by spinning gas. Some shine brightly, with a continuous supply of fuel, while others go dormant for millions of years, only to reawaken with a serendipitous influx of gas. It remains largely a mystery how gas flows across the universe to feed these massive black holes.

UConn Assistant Professor of Physics Daniel Anglés-Alcázar, lead author on a paper published today in The Astrophysical Journal, addresses some of the questions surrounding these massive and enigmatic features of the universe by using new, high-powered simulations.

“Supermassive black holes play a key role in and we are trying to understand how they grow at the centers of galaxies,” says Anglés-Alcázar. “This is very important not just because black holes are very interesting objects on their own, as sources of gravitational waves and all sorts of interesting stuff, but also because we need to understand what the central black holes are doing if we want to understand how galaxies evolve.”

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The Ophiuchus star-forming complex offers an analog for the formation of the solar system, including the sources of elements found in primitive meteorites.

A region of active star formation in the constellation Ophiuchus is giving astronomers new insights into the conditions in which our own solar system was born. In particular, a new study of the Ophiuchus star-forming complex shows how our solar system may have become enriched with short-lived radioactive elements.

Evidence of this enrichment process has been around since the 1970s, when scientists studying certain mineral inclusions in meteorites concluded that they were pristine remnants of the infant solar system and contained the decay products of short-lived radionuclides. These radioactive elements could have been blown onto the nascent solar system by a nearby exploding star (a supernova) or by the strong stellar winds from a type of massive star known as a Wolf-Rayet star.

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But a team of physicists is proposing a radical idea: Instead of forming black holes through the usual death-of-a-massive-start route, giant dark matter halos directly collapsed, forming the seeds of the first great black holes.

Supermassive black holes (SMBHs) appear early in the history of the universe, as little as a few hundred million years after the Big Bang. That rapid appearance poses a challenge to conventional models of SMBH birth and growth because it doesn’t look like there can be enough time for them to grow so massive so quickly.

“Physicists are puzzled why SMBHs in the early universe, which are located in the central regions of dark matter halos, grow so massively in a short time,” said Hai-Bo Yu, an associate professor of physics and astronomy at UC Riverside, who led a study of SMBH formation that appeared in Astrophysical Journal Letters.

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About 2,000 light-years away from Earth, there is a star catapulting toward the edge of the Milky Way. This particular star, known as LP 40–365, is one of a unique breed of fast-moving stars—remnant pieces of massive white dwarf stars—that have survived in chunks after a gigantic stellar explosion.

“This star is moving so fast that it’s almost certainly leaving the galaxy…[it’s] moving almost two million miles an hour,” says JJ Hermes, Boston University College of Arts & Sciences assistant professor of astronomy. But why is this flying object speeding out of the Milky Way? Because it’s a piece of shrapnel from a past explosion—a cosmic event known as a supernova—that’s still being propelled forward.

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