What is Dark Energy and Why is it a Mystery?

In summary, the paper is a very impressive overview of dark energy and its implications for cosmology. Padmanabhan has a way with words and makes the complex material easily understandable. He has a clear and engaging writing style that makes the paper easy to read.
  • #1
Kea
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Dark energy: Mystery of the Millenium
T. Padmanabhan
http://arxiv.org/abs/astro-ph/0603114

This is an impressive paper, based on a talk and quite readable. :smile:
 
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  • #2
Indeed, Kea. I read that one yesterday. Padmanabhan has a way with words.
 
  • #3
I just finished reading it. What a lot of good solid MEAT in that paper. Obviously based on decades of deep thought by himself and semingly everybody else, it really does give us a general NECESSARY framework for evaluating quantum gravity programs.
 
  • #4
selfAdjoint said:
...it really does give us a general NECESSARY framework for evaluating quantum gravity programs.

Yes, I thought so too. I must put some time aside to go through some of his papers. :smile:
 
  • #5
Kea said:
Yes, I thought so too. I must put some time aside to go through some of his papers. :smile:


He's got his references nicely organized by topic, I noticed. I liked the way he synthesized holography, thermodynamics, and special viewpoints to get his "model that works". Very convincing.

I was especially diverted by his choice of variables for the action: the metric, the Christoffel symbols, and the curvature tensor. Noting also that the curvature tensor, in this representstion, depends on the Christoffel symbols but not the metric. I wonder how many decades of pondering the common wisdom of GR it took to come up with that!
 
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  • #6
Kea said:
Yes, I thought so too. I must put some time aside to go through some of his papers. :smile:
What I really like is his ability reach a broad audience. Modern theorists tend to target a very narrow audience possessing great expertise in the subject material. This is not necessarily a bad thing. It's an efficient way to publish new research. Unfortunately, it leaves most of the rest of us slack-jawed. Here are some of his other papers I like:

http://www.arxiv.org/abs/astro-ph/0602280
Issues in the Philosophy of Cosmology

http://www.arxiv.org/abs/astro-ph/0602117
Advanced Topics in Cosmology: A Pedagogical Introduction

http://www.arxiv.org/abs/astro-ph/0510492 :
Darker Side of the Universe

http://www.arxiv.org/abs/gr-qc/0510015
A new perspective on Gravity and the dynamics of Spacetime

http://www.arxiv.org/abs/gr-qc/0503107
Understanding Our Universe: Current Status and Open Issues
 

FAQ: What is Dark Energy and Why is it a Mystery?

What is dark energy?

Dark energy is a theoretical form of energy that is believed to make up about 68% of the universe. It is thought to be responsible for the accelerated expansion of the universe.

How was dark energy discovered?

Dark energy was first proposed in the late 1990s when astronomers observed that the expansion of the universe was accelerating. This observation was confirmed through the use of Type Ia supernovae as standard candles for measuring distances in the universe.

What is the role of dark energy in the universe?

The primary role of dark energy is to explain the observed accelerated expansion of the universe. It is also thought to play a role in the formation of large-scale structures in the universe.

What is the evidence for dark energy?

The main evidence for dark energy comes from observations of Type Ia supernovae, as well as measurements of the cosmic microwave background radiation and the large-scale structure of the universe. These observations all support the existence of dark energy and its role in the expansion of the universe.

What is the current understanding of dark energy?

While dark energy remains a mystery, the current understanding is that it is a repulsive force that counteracts the pull of gravity and is responsible for the accelerated expansion of the universe. The exact nature of dark energy is still being studied and remains one of the biggest puzzles in modern cosmology.

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