"Dark energy" is a conventional term to describe some energy of unknown source that has the effect of accelerating space expansion with time. We call "dark energy" the thing that explains this observation, whatever that thing might be (we just assume it's some form of energy since it produces motion, acceleration, in a way seemingly opposed to, and stronger than gravity, but for all we knew it could be fluffy creatures from the 7th dimension, "energy" is just an educated guess).
If you remove the observational discrepancy, then you remove the need for "dark energy" to exist in the first place.
The article precisely suggests that:
- there was no such observational discrepancy, rather errors in calculations following observation
- reality is thus shown to conform to our current equations; it's our interpretation of the pretty pictures we took that was wrong all along; this is now corrected.
If true, it's the end of dark energy as a cause because the consequence is gone.
At no point (before or after it's proven or disproven) does "dark energy" imply a postulate on "what it actually is" — and chances are, when we explain previously unknown phenomena, the finders come up with a new theory and ad hoc terminology. Rarely the word sticks when it's just too good an intuition — e.g. the "atom".
Note that "dark matter" is exactly the same, it's a conventional term to denote some matter-like unknown object that has the effect of giving galaxies their characteristic shapes and interactions forming much larger patterns (structure about as big to individual galaxies as galaxies are to individual stars).
We already knew there was likely to be something fishy about the most distant supernovas, because we have two divergent values for the Hubble constant, one of them based on these same supernovas.
https://en.wikipedia.org/wiki/Dark_energy#Evidence_of_existe...
But that would mean that disputes about the value of the Hubble Constant are also disputes about the age of the universe, and vice versa.
The article stipulates what convinced these people that it was there, namely that they rested their conclusions on an assumption that turned out to be wrong.
This result is based on the assumption that the corrected luminosity of SN Ia through the empirical standardization would not evolve with redshift.
Which is another good reason not to make conclusive judgements based on unproven assumptions (not that everyone that "dark energy" must exist, but many did, and some people still cling to it even if the face of this study). It is also a good example of why one should never give credence to a theory or a supposition based on how many other people give it credence - stick to what you can prove.
I thought dark matter and dark energy are simply placeholders for a discrepancy we see between our models of the universe and our observations. No?
Dark energy is something predicted by general relativity and iirc it's what is behind the expansion of space (and acceleration of expansion).
Not really. GR can accommodate it just fine, but GR did not predict it. In fact, Einstein, who originally introduced the cosmological constant (which was the term then for what we now call "dark energy") in order to allow a static solution to his equation, thereby missed the chance to predict that the universe was expanding, a decade before Hubble's observations showed that it was. Once it became clear that expanding models matched the data, and did not (then) require a cosmological constant to do so, Einstein dropped it, calling it "the biggest blunder of my life". Only in the 1990s, when evidence for accelerating expansion became available, was the cosmological constant (now called "dark energy") put back into the equations so they would match the data.
> it's what is behind the expansion of space (and acceleration of expansion)
The expansion itself, no. The acceleration, yes.
If you just mean "no dark energy", i.e., the model that most cosmologists used before the 1990s when accelerating expansion was discovered, it wouldn't change the universe's long term fate very much. It would still expand forever and become more and more diluted; the expansion would just slow down forever instead of accelerating forever. There would be some differences as far as our observable universe--we would not eventually become isolated from all other galaxies and unable to see them--but that's about all.
Not saying the Nobel write-ups constitute evidence, but dark energy has certainly been popular, at least.
1 = https://www.nobelprize.org/prizes/physics/2011/press-release...
As a non-cosmologist just reading HN I would say yes. Not quite as extensively as Dark matter though. I personally think that's a mistake too based on my limited research on the topic. If these are both overturned it will be a huge blow to "scientists" credibility in the eyes of the public. That's how invested they are.
This is nonsense. Scientists have been wrong in several occasions, it is just part of the profession. For example, in the years leading to the discovery of relativity, many physicists believed there was something called "ether" that worked to fix the speed of light that they had evidence to be the same in all directions.
People are too bought into science as a source for truth instead of being a messy, difficult method of discovery.
Cosmologists could learn a lot from 19th-century chemists.
It is the fault of our education system and pop culture that people are so terrified of scientists being wrong. People should be thrilled when scientists are shown to be wrong, as it means they are one step closer to understanding what is right.
People were forced to take particle physics seriously, and cosmology slipped in on its coattails.
All we really know is that the equations we have don't match the universe we see. Dark-this and dark-that are no better than guesses that seem to bring things back in line with our favored theories, until some actual mechanism is identified.
Is he implying that other cosmologists have proceeded as if dark energy is well evidenced?