The space between streams of stars may be influenced by the presence of the universe’s most mysterious form of matter.
Category: cosmology – Page 97
Perhaps the greatest and most frustrating mystery in cosmology is the Hubble tension problem. Put simply, all the observational evidence we have points to a universe that began in a hot, dense state, and then expanded at an ever-increasing rate to become the universe we see today. Every measurement of that expansion agrees with this, but where they don’t agree is on what that rate exactly is.
We can measure expansion in lots of different ways, and while they are in the same general ballpark, their uncertainties are so small now that they don’t overlap. There is no value for the Hubble parameter that falls within the uncertainty of all measurements, hence the problem.
Of course, most of the results depend on a long chain of observational results. When we measure cosmic expansion using distant supernovae, for example, the result depends on the derived distances of these supernovae as found through the cosmic distance ladder, where ever greater distances are determined based on the distance of closer things.
The End of the Multiverse
Posted in cosmology
Audiences are falling out of love with dizzying multiverse sagas. Can the concept still be a useful lens on the psychology of regret, or is it dead on arrival?
Astronomers spot periodic lights coming from near the black hole at the center of our galaxy.
The supermassive structure dates to about 400 million years after the Big Bang, and it’s particularly large for its age.
Structure of Space-Time Video
Posted in cosmology
A Visual Model of Space and Time linking Gravity, Dark Energy, Black Holes, and Inertia.
Cosmologists believe that multiple universes really exist; they call the whole vast collection, which might even be infinite in number, the ‘multiverse’. But how are all these universes generated? There are several ways, each radically different from the others, each incredibly fascinating, each capable of generating infinite universes.
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Lee Smolin is an American theoretical physicist, a researcher at the Perimeter Institute for Theoretical Physics, and an adjunct professor of physics at the University of Waterloo. He is best known for his work in loop quantum gravity.
2303.0083v2-3.pdf
Posted in cosmology
Relationship of the photon to cosmology and the origin of the universe.
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A group of over 400 scientists have spent the last decade studying supernovae with unprecedented results about the expansion of space and the role of dark energy.
The discovery of a second ultra-large structure in the remote universe has further challenged some of the basic assumptions about cosmology.
The Big Ring in the Sky is 9.2 billion light-years from Earth. It has a diameter of about 1.3 billion light-years, and a circumference of about 4 billion light-years. If we could step outside and see it directly, the diameter of the Big Ring would need about 15 full moons to cover it.
It is the second ultra-large structure discovered by University of Central Lancashire (UCLan) Ph.D. student Alexia Lopez who, two years ago, also discovered the Giant Arc in the Sky. Remarkably, the Big Ring and the Giant Arc, which is 3.3 billion light-years across, are in the same cosmological neighborhood—they are seen at the same distance, at the same cosmic time, and are only 12 degrees apart in the sky.