Dark Energy May Be Changing

SpaceAdmiral writes "Nature is reporting that Dark energy, the hypothetical energy driving the universe's expansion, may not be as constant as previously thought. According to new research the strength of dark energy may be very different now than it was when the universe was young."

Comments

It is changing, but we don't know which way

[tod_miller]

It doesn't say if it gets stronger or weaker..

wtf

An extraordinary Claim requires...

[helioquake]

...extraordinary evidence to support it. I'm not an expert on this
topic (will hear more about it from local experts for sure), but
it doesn't sound a statistically significant claim to me.

For the life of me I can't recall a false study about something...
I think it's about pulsars / neutron star. Astronomers found the
first few pulsars and found them to be aligned in a similar
orientation. This provoked a few new thoughs and fresh ideas
among the community...but later only to realize that the first few
detections happened to be a freak series of coincidence; further
observations revealed that other pulsars orient in many different ways.

Choosing random samples is important here. I'm not sure how carefully
that thought process has been applied here by this author (i.g., that
is what Adam Rees alludes to, I think).

We have to be careful since some people tend to see what they want
to believe in.

Not THAT again...

[mcrbids]

Didn't we recently conclude that dark matter didn't really need to exist at all?

Re:That's a pretty bold statement...

[dogbreathcanada]

The science (and theories) don't necessarily change ... they evolve. Dark Matter and Dark Energy are "necessary" because there's not enough visible matter in the universe to account for the size and expansion of the universe.

String Theory Fallout

[ObsessiveMathsFreak]

There's already a few comments openly questioning and in some cases deriding the concept of dark energy. I think this could well be fallout from String Theory's current fall from grace.

It's looking more and more like String Theorists are on the wrong track. I think this may have bred a new skeptisism in people with regard to the more "out there" physics theories.

The whole debate about Intelligent Design may also be playing a part. There's been a very public question about "what is science". String Theory has already come under fire from this, and it's understandable that some other theories such as Dark Energy might also be brought under the spotlight of a new skeptisism.

This might be stifling for scientists, paticularly those with more outlandish sounding, but still reasonable hypotheses. But ultimately I think it will be good for science. No one should blindly accept any scientific theory without sufficient evidence. And supplying that evidence can only further validate the theory. In this sense, skeptics are good for science.

Re:That's a pretty bold statement...

[spectrumCoder]

There are many massless particles in physics. Photons, for instance.

Note that it makes just as much sense to talk about gravity waves as it does to talk about gravity particles, and no one assumes waves have to have mass.

Dark energy, dark matter and gravitons are all theoretical concepts postulated to help make the world make sense to physicists. But that doesn't mean they exist.

Re:IANAP but...

[heatdeath]

Maybe its just the engineer in me, but isn't it possible that we're just observing some other unknown effect.

MOND

Been there, seen that

[Omega Blue]

It wasn't that long ago - probably a year or two - that some researchers were claiming that c (speed of light) decreased since the Bang. I was quite skeptical at the time, because changing c is going to change the among of energy and matter in our universe.

Up till today I haven't seen another team confirming this.

Re: more information

[Black Parrot]

> This is the actual press release from Dr. Schaefer.
http://www.phys.lsu.edu/GRBHD/pressrelease/ It seems that the results are very damning to cosmological constants.

It seems that even if he's right it would only require one cosmological constant to be non-constant.

Or maybe not even that. Maybe the effect he's observing is dependent on something that changes with times, such as the temperature or density of the universe. Most cosmologists already believe the universe underwent a sort of "phase change" during the inflationary period, and it hasn't exactly destroyed the idea of cosmological constants.

dark energy linked to hubble constant

[clockwork_orange]

it was already suspected that dark matter and dark energy were different when the universe was young, they are both linked to the hubble constant H, which is different the further back in time you go. it might be new evidence i haven't read the paper in nature yet, but its not a new idea

Some astronomers doubt this result

[Wormholio]

A longer article on this in the NY Times says that other astronomers doubt this result.

Obligatory Douglas Adams quote

[ozbird]

"There is a theory which states that if ever anybody discovers exactly what the Universe is for and why it is here, it will instantly disappear and be replaced by something even more bizarre and inexplicable.

There is another theory which states that this has already happened."

Re:That's a pretty bold statement...

[Anonymous Coward]

IIRC, the whole beauty behind Dark Matter is it is supposed to be some constant that solves the problems we have with understanding how the universe operates. If that constant is not constant, then doesn't that sort of ruin the value?

You're confusing dark matter and dark energy, and no, a non-constant dark energy doesn't ruin anything. The point of dark energy, like any theory, is to explain our observations. If our observations indicate that the universe is expanding in a weird way, we may need a weird explanation to account for it.

I'm just reminded of the tendency of science. We make an observation and derive a theory. The theory does not fit subsequent observations, so we try to force the observation to fit the theory.

No, we modify the theory to fit the observations. That's why we replaced a theory with no dark energy by a theory with dark energy, and may need to replace that with a theory involving time-varying dark energy. These modifications are driven by new observations.

Now, it is becoming scientific heresy to say there is no Dark Matter.

Nonsense. What is true is that more and more observations have proven to be consistent with dark matter, and so it is becoming harder and harder to come up with an alternative that is also consistent with all that evidence. That is exactly the process by which new theories become accepted.

Well, I for one do not put any salt in DM because it's unobservable.

You're joking, right? Dark matter is postulated precisely because it has a great many observable consequences. We observe it through gravity.

Sort of like a Devine creator--we can't observe him so we assume he does not exist. So, why do we assume there is DM?

Actually, we can attribute any of our observations to the actions of a divine creator, and thus "support" his existence. The reason why that's not considered scientific is because the divine creator hypothesis makes little in the way of specific, testable, and falsifiable predictions regarding independent phenomena. But dark matter, like all other good scientific theories, does.

the fundamental flaw

[nido]

it's the old materialism vs. vitalism "holy war".

Scientists in the persuasion of Materialism believe that the universe is fundamentally composed of matter.

Vitalists maintain that the physical universe is just a very tiny subset of "all that is". Conciousness is primary, the physical universe is the playground that we all are currently occupying.

Matrix terminology: Conciousness is "the real world", whereas the physical universe is "the matrix". The movie was based on buddhist philosophy, so it is an apt analogy.

See Ingo Swann's Psychic Sexuality for more on the age-old Materialism vs. Vitalism debate, from a decidedly pro-vitalist perspective. (Sexuality being, of course, where most of us encounter vitalism-related phenomena).