Far out cosmology: cosmic strings exist? (Introduction)

by David Turell , Thursday, April 26, 2018, 01:27 (2186 days ago) @ David Turell

These are theorized as being fine cracks in the universe and are thought, if they exist, to be pure energy:

https://cosmosmagazine.com/physics/cracks-in-the-universe

"Our universe exploded into being, expanded at a fantastic speed and cooled. Perhaps too quickly. Some physicists believe the rapid cooling might have cracked the fabric of the universe.

"These hairline fractures may still be threaded through space-time. Dubbed cosmic strings, mathematical models see them as invisible threads of pure energy, thinner than an atom but light-years long. The huge amount of energy they contain also makes them extremely heavy; a few centimetres of cosmic string might weigh as much as Mount Everest.

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"However, as time capsules of the early universe, cosmic strings should retain fantastic energies – more than a billion times greater than those released by smashing particles at the Large Hadron Collider, says Ken Olum, a theoretical physicist at Tufts University in Boston, who has contemplated cosmic strings for 20 years. “You can’t build an accelerator to test physics at that scale.”

"Neither can any of our astronomical instruments detect these vanishingly thin, intergalactic filaments. For some physicists, a theory that can’t be tested is not worth pursuing. It places cosmic strings in the same category as “string theory”, their controversial namesake at the other extreme of the size scale......For Matthew Bailes, an astrophysicist at Swinburne University of Technology in Melbourne, cosmic strings are a “mathematical curiosity” or worse, “an exotic fantasy”.

"All that may be about to change. The nascent era of gravitational wave astronomy – just two years old – may finally deliver a tool to test the existence of cosmic strings. We can’t see them but gravitational wave detectors might be able to hear the thrums and snaps created as they whip through space.

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"British field theorist Tom Kibble, who died in June 2016, came up with the idea of cosmic strings in 1976. He was musing about the first split second after the Big Bang when the universe underwent a rapid expansion, then cooled rapidly. This, he suggested, caused a phase change in the quantum fields, like water freezing to ice.

"In a block of ice, some regions can freeze with their crystals in different orientations, rather like tiles being laid simultaneously at different ends of a room. Where they meet, they don’t fit together smoothly, resulting in a crack. Likewise Kibble surmised that the quantum phase changes in the early universe would have caused the fields to align in different orientations, again causing cracks – cosmic strings.

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'Vilenkin was thinking about this problem when he picked up on an aside in Kibble’s 1976 paper: when a cosmic string wriggling in the void crossed itself, it would chop off a self-contained ‘loop’. These loops would be light-year-sized hula-hoops in space – and enormously heavy. Vilenkin ran the numbers, and realised the number of cosmic loops that would have existed in the early universe was curiously close to the number of galaxies. Perhaps, he reasoned, a cosmic loop could seed a young galaxy, much like a grain of sand seeds a pearl.

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"Cosmic strings can’t be seen but they might be heard. Gravitational waves are ripples in spacetime generated by massive objects moving extremely fast – like a pair of inspiralling black holes or neutron stars. Or a writhing cosmic string.

“'What happens is like a whip,” explains Damour, who worked out the idea with Vilenkin in 2000. The crack of a bullwhip is actually a sonic boom caused when part of its tail moves faster than the speed of sound.

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"Even if the evidence continues to come up negative, some physicists are unlikely to let go of cosmic strings. Siemens says the strings might have been formed with too low an energy to give off any signals “detectable in the near future”. Another possibility is that ancient cosmic strings radiated away their energy and faded to nothingness too quickly after the Big Bang to have left a lasting impression.

"For now, cosmic strings sit on the shelf alongside other beautiful ideas that could complete our understanding of the universe, but lack empirical support. “This is the beauty and the danger of physics,” Damour says. “Sometimes things exist that we can never see.'”

Comment: Really far out, but the significance for me is that the theorists say that pure energy can exist. It is my theory about God that He is the First Cause, and He thinks and plans without any matter neurons and the universe is an extension of some of His energy, planned and formed by Him and evolved by Him.