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I haven't done any physics past high school but isn't dark energy basically "Our equations don't work out, let's give our error term a name and act like it's al

by psv1 7y ago

I haven't done any physics past high school but isn't dark energy basically "Our equations don't work out, let's give our error term a name and act like it's all good"? I'm sure this is oversimplified or outright wrong, can anyone correct me?

cthalupa 7y ago
>"Our equations don't work out, let's give our error term a name and act like it's all good" Not really. People make this argument for both dark energy and dark matter, and some people try to solve both of these (not necessarily at the same time) by trying to modify general relativity. The problem is that we have observational evidence for both of them, and no alternative theory has come close to the level of accuracy and precision as GR has. That isn't to say that we shouldn't be looking at potential alternative explanations to DM/DE, and the fact that there isn't scientific consensus on them at current doesn't mean that they're wrong (Wegener basically ended up losing his career over proposing continental drift was a thing), but at present, scientific consensus is overwhelmingly in favor of both DE and DM existing because we have more evidence for them than anything else, and the models that incorporate them are more accurate and precise than anything else. That's not to say there isn't room for improvement in GR/SR/QM, etc. And there are some things where the math breaks down and we do sort of just shrug. Topically, black holes are among them - at least when it comes to the singularity and infinite density. In reality, the black holes we see out in the universe almost certainly don't have a point of infinite density.
dwaltrip 7y ago
You make it sound like the scientists are doing something shady, which is completely untrue... plenty of good science has been done on dark energy / dark matter. This is simply a prime example of how it looks when important observations aren't fully understood. So that's a problem with your wording.
MiroF 7y ago
"Our equations don't work out, let's give our error term a name and act like it's all good" Much more true for dark matter and still not really. The cumulative body of evidence suggests that this is due to real mass-energy out there.
contravariant 7y ago
Dark energy has a bit of a weird history. Initially Einstein included it (or rather something like it) in his equations for general relativity because it fitted nicely and otherwise a static universe would eventually implode, only later it became clear that the universe was expanding and Einstein famously called this parameter his biggest mistake, except that in the current theory the value is very much not 0 (although annoyingly it's a lot closer to 0 than quantum physics says it ought to be, so much so that this has been called the worst prediction in physics). So yeah, the debate about dark energy is responsible for 'Einstein's biggest mistake' and 'the worst prediction in physics'. Either way it wasn't simply a case of "let's just give our error term a fancy name and call it a day".
jaf656s 7y ago
The reality is closer to: We have a lot of observational evidence that the equations are very accurate. But when we put all the mass we know about into the equations, the result of the equation doesn't match our observations. Since we have a lot of evidence that the equations are very accurate, then it's more likely that there's more mass we haven't accounted for. (at least for dark matter)
- ars 7y ago
  That's dark matter, dark energy is something else entirely, with much flimsier data and evidence.
  - jaf656s 7y ago
    whoops, I thought they said dark energy/matter
lalaithion 7y ago
In the high atmosphere, a bunch of floating bacteria have figured out physics-- kinetic energy, electromagnetism, momentum, electric potential, etc --but they have no notion of gravity, being high up and feeling the turbulent forces of air with a much greater strength than the pull downward. Eventually, their astrophysicists say "Look, the cosmos behaves very similarly to how our models predict, except there seems to be an extra force or energy that pulls everything in one direction. If we just add one term to every potential energy equation we have, it all makes sense, but we have no idea where that energy actually comes from."

by psv1 7y ago

cthalupa 7y ago

>"Our equations don't work out, let's give our error term a name and act like it's all good" Not really. People make this argument for both dark energy and dark matter, and some people try to solve both of these (not necessarily at the same time) by trying to modify general relativity. The problem is that we have observational evidence for both of them, and no alternative theory has come close to the level of accuracy and precision as GR has. That isn't to say that we shouldn't be looking at potential alternative explanations to DM/DE, and the fact that there isn't scientific consensus on them at current doesn't mean that they're wrong (Wegener basically ended up losing his career over proposing continental drift was a thing), but at present, scientific consensus is overwhelmingly in favor of both DE and DM existing because we have more evidence for them than anything else, and the models that incorporate them are more accurate and precise than anything else. That's not to say there isn't room for improvement in GR/SR/QM, etc. And there are some things where the math breaks down and we do sort of just shrug. Topically, black holes are among them - at least when it comes to the singularity and infinite density. In reality, the black holes we see out in the universe almost certainly don't have a point of infinite density.

dwaltrip 7y ago

You make it sound like the scientists are doing something shady, which is completely untrue... plenty of good science has been done on dark energy / dark matter. This is simply a prime example of how it looks when important observations aren't fully understood. So that's a problem with your wording.

MiroF 7y ago

"Our equations don't work out, let's give our error term a name and act like it's all good" Much more true for dark matter and still not really. The cumulative body of evidence suggests that this is due to real mass-energy out there.

contravariant 7y ago

Dark energy has a bit of a weird history. Initially Einstein included it (or rather something like it) in his equations for general relativity because it fitted nicely and otherwise a static universe would eventually implode, only later it became clear that the universe was expanding and Einstein famously called this parameter his biggest mistake, except that in the current theory the value is very much not 0 (although annoyingly it's a lot closer to 0 than quantum physics says it ought to be, so much so that this has been called the worst prediction in physics). So yeah, the debate about dark energy is responsible for 'Einstein's biggest mistake' and 'the worst prediction in physics'. Either way it wasn't simply a case of "let's just give our error term a fancy name and call it a day".

jaf656s 7y ago

The reality is closer to: We have a lot of observational evidence that the equations are very accurate. But when we put all the mass we know about into the equations, the result of the equation doesn't match our observations. Since we have a lot of evidence that the equations are very accurate, then it's more likely that there's more mass we haven't accounted for. (at least for dark matter)

ars 7y ago
That's dark matter, dark energy is something else entirely, with much flimsier data and evidence.
- jaf656s 7y ago
  whoops, I thought they said dark energy/matter

lalaithion 7y ago

In the high atmosphere, a bunch of floating bacteria have figured out physics-- kinetic energy, electromagnetism, momentum, electric potential, etc --but they have no notion of gravity, being high up and feeling the turbulent forces of air with a much greater strength than the pull downward. Eventually, their astrophysicists say "Look, the cosmos behaves very similarly to how our models predict, except there seems to be an extra force or energy that pulls everything in one direction. If we just add one term to every potential energy equation we have, it all makes sense, but we have no idea where that energy actually comes from."