Category: cosmology

Black Holes, Quantum Information, and the Stru…

Black Holes, Quantum Information, and the Structure of Spacetime:

Readings.

Quantum to Cosmos

Quantum to Cosmos:

Worth a visit, no doubt.

ESA’s star mapping mission, Gaia, has shown ou…

ESA’s star mapping mission, Gaia, has shown our Milky Way galaxy is still enduring the effects of a near collision that set millions of stars moving like ripples on a pond.

Via ESA: Gaia hints at our Galaxy’s turbulent life

Is our universe one of many? Stanford-news fiv…

Is our universe one of many?

Stanford-news five-part series on the String Theory Landscape, by Ker Than (illustrations by Eric Nyquist).

Long and Winding Road: A Conversation with Str…

Long and Winding Road: A Conversation with String Theory Pioneer | Caltech:

Cool interview with John Schwarz pioneer and co-father of the first superstring revolution.

“After the 1984 to 1985 breakthroughs in our understanding of superstring theory, the subject no longer could be ignored. At that time it acquired some prominent critics, including Richard Feynman and Stephen Hawking. Feynman’s skepticism of superstring theory was based mostly on the concern that it could not be tested experimentally. This was a valid concern, which my collaborators and I shared. However, Feynman did want to learn more, so I spent several hours explaining the essential ideas to him. Thirty years later, it is still true that there is no smoking-gun experimental confirmation of superstring theory, though it has proved its value in other ways. The most likely possibility for experimental support in the foreseeable future would be the discovery of supersymmetry particles. So far, they have not shown up.”

Simulation of the orbits of stars very close t…

Simulation of the orbits of stars very close to the supermassive black hole at the heart of the Milky Way (above). One of these stars, named S2 (below), orbits every 16 years and did pass very close to the black hole in May 2018.

Full story at ESO: First Successful Test of Einstein’s General Relativity Near Supermassive Black Hole

Cosmic microwave background image based o…

Cosmic microwave background

image based on data from the Planck Legacy release, the mission’s final data release, published in July 2018.

The image above is a zoom from next area:

More from the European Space Agency (ESA):

New model predicts that we’re probably t…

New model predicts that we’re probably the only advanced civilization in the observable universe. Via Universe Today.

Well, playing with the Drake equation and the Fermi paradox is always fun and educative, as long as you assume that you are on a purely speculative ground. We actually don’t know, and the “probably” adverb in the title is central.

From the original paper’s abstract (Dissolving the Fermi ParadoxPDF):

[…] The expectation that the universe should be teeming with intelligent life is linked to models like the Drake equation, which suggest that even if the probability of intelligent life developing at a given site is small, the sheer multitude of possible sites should nonetheless yield a large number of potentially observable civilizations. We show that this conflict arises from the use of Drake-like equations, which implicitly assume certainty regarding highly uncertain parameters. We examine these parameters, incorporating models of chemical and genetic transitions on paths to the origin of life, and show that extant scientific knowledge corresponds to uncertainties that span multiple orders of magnitude. This makes a stark difference.

A pioneering physicist explains why it’s okay …

A pioneering physicist explains why it’s okay to not have all the answers:

Interesting interview with theorist Brian Greene, I liked his concept of personalized education, I think he could be quite right on this.

“[…] I think in some number of years we’ll have a far more personalized approach to education. Kids are different. They come at things completely differently, different DNA, different experiences. If we could allow them to drive the right way to learn for their particular biochemical and neurophysiological make-up, how much more powerful would that be than a one-size-fits-all approach, which is what we do now?

Hubble Space Telescope: Cosmic collision light…

Hubble Space Telescope: Cosmic collision lights up the darkness

Though it resembles a peaceful rose swirling in the darkness of the cosmos, NGC 3256 is actually the site of a violent clash. This distorted galaxy is the relic of a collision between two spiral galaxies, estimated to have occurred 500 million years ago. Today it is still reeling in the aftermath of this event.

Credit: ESA/Hubble, NASA, CC BY 4.0