Dark Energy - video lecture by Risa Wechsler

[LorrB]

Dark Energy - video lecture by Risa Wechsler

Risa Wechsler - Dark Energy. What the ...?

Abstract:
What is the Universe made of? This question has been asked as long as humans have been questioning, and astronomers and physicists are finally converging on an answer. The picture which has emerged from numerous complementary observations over the past decade is a surprising one: most of the matter in the Universe isn't visible, and most of the Universe isn't even made of matter. In this talk, I will explain what the rest of this stuff, known as "Dark Energy" is, how it is related to the so-called "Dark Matter", how it impacts the evolution of the Universe, and how we can study the dark universe using observations of light from current and future telescopes.

About the speaker:
Risa Wechsler is a theoretical cosmologist whose research focuses on understanding how quantum fluctuations in the early Universe develop into the galaxies and large structures of galaxies that we see today. She also works to understand how observations of galaxies can constrain the nature of the dark matter and dark energy that pervade our Universe.

Risa received her S.B from MIT in 1996 and her PhD from University of California at Santa Cruz in 2001. She did postdoctoral work at the University of Michigan and at the University of Chicago, where she was a Hubble Fellow and Enrico Fermi Fellow. She joined the faculty at SLAC and at the Stanford Physics Department as an Assistant Professor in 2006. She is also a member of the Kavli Institute for Particle Astrophysics and Cosmology.

Download link:
www2.slac.stanford.edu/lectures/video/PLec103007.ram

[paul]

I sometimes wonder if dark matter, dark energy, dark ages and missing links are conceptual devices to prop up theories that do not match the data.

For example: "Given the speed at which galaxies are rotating, the gravity of the stars we can see is not enough to keep the galaxies from flying apart."


Now a simple-minded human might think: There must be some other force present.

But scientists are too smart for that and think: " That means that 95 per cent of the matter must be dark - only detectable by its gravitational effect."

And a new branch of science is born

[stepnwolf]

The URL given in the message lead to a dead end. The video can now be seen at

[stepnwolf]

vimeo.com/31103691 didn't appear

[LorrB]

Thanks stephwolf.

Paul ... maybe we call things dark because we can't throw any light on the subject
Space is just something we can't see. If space can be bent, then it must be something, one force or other.

Electromagnatism?

www.school-for-champions.com/science/electromagnetism.htm

[paul]

>maybe we call things dark because we can't throw any light on the subject

They are dark because we cannot see them. Often we cannot see them because they are not what we think or not there at all.

Lack of observation does not seem to matter in some areas of science. Theories are adapted by introduction of unobservable entities.

[LorrB]

Careful, henka might see that post ;D ;D ;D

[paul]

>it was classified as the language of exact representation!

It is said that in esoteric traditions that there are sacred languages. One of the characteristics of such languages is that words when pronounced manifest the qualities of what is named and that those qualities are detectable by the enlightened human.

For example in a sacred language the word for apple may induce some experience of appleness in the consciousness of the initiate.

Ancient Sanskrit is said to be a sacred language. makara.us/05ref/02comps/Senzar.htm

Long ago I saw in meditation a document that may have been written in a sacred language. The document was in what looked like 3D symbols, written from right to left. My comprehension was somewhat limited but the document seemed to be a list of beings and their roles in the higher realms.

[paul]

>Often we cannot see them because they are not what we think or not there at all.


"Astrophysicists using Europe’s MPG/ESO 2.2 meter telescope in Chile have discovered that the dark matter in the universe is not where it is supposed to be. This discovery threatens years of assumptions about the universe and the theorized dark matter that is supposed to comprise most of the universe."

commonsenseconspiracy.com/2012/04/where-has-all-the-dark-matter-gone/

[paul]

More bad news for dark matter and energy

"Researchers at the LHCb detector have dealt a serious blow to this idea........If superparticles were to exist the decay would happen far more often. This test is one of the "golden" tests for supersymmetry and it is one that on the face of it this hugely popular theory among physicists has failed."


www.bbc.co.uk/news/science-environment-20300100

[mgc]

"maybe we call things dark because we can't throw any light on the subject"
its the other way round. we call it dark because the subject cant throw light on us.

mind moving this thread to hidden mysteries?

"What is the Universe made of?"
strings! maybe.

[paul]

>"What is the Universe made of?"

In esoteric traditions around the planet, the universe is alive.

[paul]

Apparently postulating dark matter and dark energy are not enough to deal with the problems of physics theory when faced with measurements. Now we need to consider dark radiation.

"The bottom line is that the universe to almost certainly more complex than we thought – and its already byzantine. To explain other puzzling observations, cosmologists have postulated a number of substances that affect the expansion rate.

Firstly there is dark energy, which is designed to accelerate the expansion of the universe. Maybe these new observations suggest that it is growing in strength.

Secondly, there is dark matter. Despite suspecting its existence for decades now, astronomers and physicists are no closer to detecting a single particle of the stuff. Could it be behaving in a way that affects the expansion?

Thirdly, could there be a kind of dark radiation? This would invisibly carry energy around the cosmos, altering the expansion."

www.theguardian.com/science/across-the-universe/2017/jan/26/speedy-universe-expansion-challenges-einsteins-theory

And the answer is given here:

"Fourthly, could there be a problem with Einstein’s general theory of relativity? This is the mathematical framework that astronomers use to calculate Hubble’s Constant based on the matter and energy contained in space. If those equations are even slightly off, then we could have everything else right and still be getting the wrong answer."


Until about 1990 science journals rarely accepted articles critical of the General Theory of Relativity. Now it seems that criticism of Einstein is permitted.

[fjrogers]

> Until about 1990 science journals rarely accepted articles critical of the General Theory of Relativity. Now it seems that criticism of Einstein is permitted.

I believe the General Theory of Relativity has been under criticism for a number of years. Some experts seem to think there are problems in the theory. I guess time will tell in the future as the world acquires more knowledge.

[paul]

One of the assumptions of materialistic science is that the Cosmos, at a macro level, is uniform in all directions. This assumption is important for a Cosmos that came into existence without any intelligence fiddling with its structure.

The problem is that the Cosmos at a macro level does have a pattern - a central line that is called The Axis of Evil.

It is called that because the central line is so disturbing to scientists that want the Cosmos to be random.

www.newscientist.com/article/mg23030710-300-thats-odd-axis-of-evil-stretches-across-the-cosmos/

[fjrogers]

I'm sure there are many cosmic complications we have yet to unfold. Some scientists will not accept intelligent design as it interferes with their own principles. There are many tests and trials to come as time will tell.

[paul]

"The Milky Way is being “pushed” through space by a cosmic dead zone that lurks half a billion light years from Earth, researchers claim."

www.theguardian.com/science/2017/jan/30/milky-way-being-pushed-through-space-by-cosmic-dead-zone-say-scientists

Has anti-gravity been discovered?

[paul]

Dark matter and dark energy are about to be phased out. It should be possible to buy them cheaply.

"These two hypotheses, it has been argued, account for the movement of stars in galaxies and for the accelerating expansion of the universe respectively. But -- according to a researcher at the University of Geneva (UNIGE), Switzerland -- these concepts may be no longer valid: the phenomena they are supposed to describe can be demonstrated without them. "

www.sciencedaily.com/releases/2017/11/171122113013.htm

[fjrogers]

Sounds interesting and we've got so much more to learn about the universe than we have ever realised. The more questions we ask the less we seem to know.