Why is space three-dimensional?

(Phys.org)—The question of why space is three-dimensional (3D) and not some other number of dimensions has puzzled philosophers and scientists since ancient Greece. Space-time overall is four-dimensional, or (3 + 1)-dimensional, ...

Can R2 gravity explain dark matter?

(PhysOrg.com) -- "In many ways, the standard model of cosmology works very well," Jose Cembranos tells PhysOrg. "However, there are very basic features that we just do not know. We have dark energy and dark matter. They dictate ...

The dark side of cosmology

It's a beautiful theory: the standard model of cosmology describes the universe using just six parameters. But it is also strange. The model predicts that dark matter and dark energy – two mysterious entities that have ...

Most distant blazar is a high-energy astrophysics puzzle

(Phys.org) —Blazars are the brightest of active galactic nuclei, and many emit very high-energy gamma rays. New observations of the blazar known as PKS 1424+240 show that it is the most distant known source of very high-energy ...

Suzaku 'post-mortem' yields insight into Kepler's supernova

(Phys.org) —An exploding star observed in 1604 by the German astronomer Johannes Kepler held a greater fraction of heavy elements than the sun, according to an analysis of X-ray observations from the Japan-led Suzaku satellite. ...

Dark matter mystery deepens

(PhysOrg.com) -- Like all galaxies, our Milky Way is home to a strange substance called dark matter. Dark matter is invisible, betraying its presence only through its gravitational pull. Without dark matter holding them together, ...

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