New Clues About the Nature of Dark Energy

Jim Mansfield writes "With the Hubble space telescope no longer being serviced by NASA, it's good to see one of their hardest working and most famous satellites in the news again. According to their press release on the nature of dark energy, Einstein may have been right after all - and even if he turns out to have been wrong, it seems that dark energy is not going 'to cause an end to the universe any time soon' ... whew, that's a relief." See also a space.com story.

Comments

Re:The restaurant at the end of the universe

[dapyx]

Yes. the total lifespan of the universe must be 42 billion.

14 billion already passed, there are 28 billion remaining, and that's close to the 30 billion figure they said.

Dark Matter and Ether

[GerritHoll]

I find it strange that scientists 'believe' in dark matter. The main reason for the hypothesis that dark matter exists, is that otherwise those huge systems of galaxies don't obey Newton's laws. However, throughout the 20th century, there have been numerous occasions where Newton either was proven wrong or where fields of science were found where his laws weren't applicable: ether didn't exist, at nanoscale Newton's laws don't apply (quantum mechanics), at very high velocities they don't either (relativity), and in very complex systems Newton can't be used (chaos). Why would it be so strange if systems with enormous scales and very small accelarations would not obey Newton's laws? It does feel a bit like Ether to me to introduce a form of matter/energy which has never been measured at all...

I think dark matter doesn't exist. It can be useful in the models, like ether could, but nothing more than that.

Re:non-physical physics

[poindextrose]

A lot of new physics does seem to be increasingly theoretical and "out there" on the proverbial limb

All new physics is out on the proverbial limb. Galileo's ideas were so outrageous at the time that the church had him outcast from society (IIRC).

It doesn't take that much of an open mind to consider these new (or old) theories based on new facts. But, I'm glad the majority don't follow such theories, because most people tend not to leave things in the grey ("THIS theory is RIGHT") otherwise, actual scientific progress would be severely hindered, as people would become quite disheartened, and possibly ANGRY at science.

It would be good for the practical lot to catch up with the theoretical lot...

The border between "Practical" and "Theoretical" isn't very black-and-white either. Often theoretical sceince leads to very practical applications (as in the case of forward error correction, originally just mathematics) and practical turns out quite sour (as in the Wankel(?) engine).

Just my 2c

Re:Correct me if I'm wrong

[ooby]

Prior to Kepler, scientists believed their was a planet Vulcan that shared Earth's orbit but the two were 180 degrees apart. Vulcan had the same mass as Earth and without the planet, scientists couldn't fit Earth's orbit into the Law of Universal Gravity.

Re:Relief?

[Gr8Apes]

1) I seem to recall there's no such thing as maximum entropy. There's just the law that for any closed system, entropy never decreases. (Third law of Thermo? It's been waay too long ago...;)

2) The eventual cold death/ever expanding argument. I think they're still trying to figure out which way the universe is going to go.

If only the universe were as simple as E=mc2

Einstein was wrong anyway

[KjetilK]

It wasn't the introduction of the cosmological constant per se that Einstein thought of as his greatest blunder, it was the failure to realize and predict that the Universe is expanding. The cosmological constant he had there to get a static universe, and that's bad. Also, the cosmological constant isn't Evil, it comes rather naturally from solving the equations. I never got as far as actually doing that, but I followed a back-of-envelope solution once, and it comes out sort of like an integration constant. I think of it as a natural parameter that should be constrained by observations just like any other parameter, and I see no particular reason why it should be 0.

Re: Einstein was wrong anyway

[Black Parrot]

> This whole "Eistein was right after all" angle is misinformed. He wanted a static universe because that was the historic conception of the universe. His own science didn't allow for it, but he wrangled an equation for one out of it anyway.

Remember that at the time Einstein introduced it (1917, if a Web search didn't lead me astray) scientists still thought "the universe" and "the galaxy" were the same thing. We tend to forget how vastly our understanding of the universe has changed in the past ~80 years.

Re:The restaurant at the end of the universe

[j0n4th4nb34r]

Time, distance, it's all space-time...

Re:http://www.ebtx.com/ntx/ntx16.htm

[Anonymous Coward]

Whats more likely? This mysterous dark energy exists and compromises 70% of the mass/enery of the universe even though we can't see it anywhere locally, or our theories are wrong?

Either way, our theories are wrong, because they didn't predict an accelerating expansion. The question is, are our theories about the matter/field/vacuum content of the universe wrong (dark energy/cosmological constant), or are other theories (such as our theories of gravity) wrong? You obviously seem to prefer the latter, but why?

I suggest reading www.ebtx.com on the nature of dark energy. This guy is right, or at least close.

What nonsense. He doesn't even have a theory, let alone a right one. He doesn't have any physical laws (i.e., equations) that can even qualitatively be compared to observational data, let alone quantitatively compared. Where is his calculation of the Tully-Fisher relation? The CMBR anisotropies? His derivation of early universe structure formation? How can you claim that this guy is even close to right, when his ideas can't be scientifically compared to experimental evidence??

The rest of the theory explains that space attracts space, and matter repels space. Matter and space are polar opposites (as well as logical opposites).

Gee, that sounds deep, but can I use it to predict anything meaningful, like a flat rotation curve?

Re:...End of time?

[egomaniac]

I always wonder whether the "It's accelerating so it'll drift apart in the end" folks understand basic calculus.

You always wonder whether astrophysicists understand basic calculus?

I'm doing my best to come up with something witty or intelligent to say to that, but I'm having trouble coming up with anything more than "What...? Huh?"

Considering that modern physics is largely just a whole hell of a lot of math, yes, I think it's safe to say that astrophysicists understand the principles of calculus. Have you even seen a modern physics paper?

Asimov

[gd2shoe]

Isaac Asimov is certainly best known for his work as a science fiction writer. What most people don't know is that he also knew and enjoyed science. I don't have the understanding to discuss many of the theories that I have read here being debated, but I think something Isaac said once bears repeating. From his scientific work "The Neutrino", let me paraphrase:

If you take a red ball, and throw it up in the air, you will observe it come back down. You can repeat the experiment with the same results. You can use a different red ball. Eventually you may adopt the theory that red balls when thrown up must come back down. You may eventually expand that theory to include blue balls, and then green balls, and then any ball. That would lead to further experimentation and the conclusion that "what goes up, must come down."

Later on though, you may let go of the helium balloon that you were holding. Helium balloons do come back down once they've gone flat, but you may need to modify your theory to say "what goes up, must come down, but not necessarily right away." Airplanes do this too. But what if something reaches escape velocity.

"What goes up, must come down, but not necessarily right away, and only if it doesn't reach escape velocity."

As our knowledge and data base grows, our theories expand or get thrown out in favor of something that better fits our observations. But they are just that: our observations. If a model doesn't fit an observation, don't blame the model, or the observation, or the scientist. Such will only be modified again as our understanding grows.