<p>Looking to see if the cosmic acceleration is increasing, steady or decreasing</p>

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2022-01-30T01:46:30.113Z
Can you provide some more detail / context for you question such as where you saw the statement in the title you are asking about?
GrapefruitIsAwesome
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2022-01-30T03:13:20.360Z
Jerk could be a reference to "change in acceleration", but that's not dimensionless.
Greg Miller
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2022-01-30T03:28:50.987Z
It could be dimensionless if normalized to something, some time and distance scale, like 1 year = 2 and AU = 1 Then perhaps a dimensionless jerk of unity would put the Earth on an escape trajectory from the solar system?
uhoh
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2022-01-30T04:27:14.383Z
Please clarify your specific problem or provide additional details to highlight exactly what you need. As it's currently written, it's hard to tell exactly what you're asking.
Community
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2022-01-30T19:00:38.280Z
Please formulate your question equally carefully as you expect an answer. Give some context, tell where you come from, and what you expect from an answer
planetmaker
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2022-01-31T11:20:12.363Z
I guess the real answer to my question is 'we don't know'. The implied question 'is the dark energy acceleration increasing, steady or decreasing?' also appears to be 'we don't know' -
Moggsy8
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2022-01-31T12:30:58.490Z
How confusing:  in classical mechanics,  "jerk" is the derivative of acceleration and most certainly has dimensions $\frac{m}{t^3}$  (as Greg M) pointed out)
Carl Witthoft
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2022-02-02T21:24:51.013Z
@Moggsy8 Don't guess. That the best Answer to the Question as Asked is 'we don't know' is about the Question, not the topic.

If you're looking to see whether cosmic acceleration is changing you might get away with something about directionless jerk. How is that the same? 

If you're saying the Question implies anything about "dark energy" I confess, I wholly missed that, perhaps due to my limited understanding.

Can you re-phrase it for simple people?
Robbie Goodwin
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2022-02-03T23:55:32.347Z
I'm still none the wiser - if this pedantry is typical, I'm back to Quora! -Moggsy8
Moggsy8
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2022-02-04T00:31:01.873Z
OK then; searching to find out if cosmic acceleration is changing, the only answer that was clear enough to remember was JERK=1 with comment about dimensionless. All refs I found were 10-20 years old so I assumed this would be well answered by now and only my ignorance of current technical jargon prevented my understanding. Moggsy8.
Moggsy8
<cosmology>
What does dimensionless Jerk=1 mean?
Moggsy8
# What does dimensionless Jerk=1 mean?

(Asked by: username_0 on 2022-01-30)

Looking to see if the cosmic acceleration is increasing, steady or decreasing

**Tags:** cosmology
> **Comments:**
> **username_1**: Can you provide some more detail / context for you question such as where you saw the statement in the title you are asking about?  
> **username_2**: Jerk could be a reference to "change in acceleration", but that's not dimensionless.  
> **username_3**: It could be dimensionless if normalized to something, some time and distance scale, like 1 year = 2 and AU = 1 Then perhaps a dimensionless jerk of unity would put the Earth on an escape trajectory from the solar system?  
> **username_4**: Please clarify your specific problem or provide additional details to highlight exactly what you need. As it's currently written, it's hard to tell exactly what you're asking.  
> **username_5**: Please formulate your question equally carefully as you expect an answer. Give some context, tell where you come from, and what you expect from an answer  
> **username_0**: I guess the real answer to my question is 'we don't know'. The implied question 'is the dark energy acceleration increasing, steady or decreasing?' also appears to be 'we don't know' -  
> **username_6**: How confusing:  in classical mechanics,  "jerk" is the derivative of acceleration and most certainly has dimensions $\frac{m}{t^3}$  (as Greg M) pointed out)  
> **username_7**: @Moggsy8 Don't guess. That the best Answer to the Question as Asked is 'we don't know' is about the Question, not the topic.  If you're looking to see whether cosmic acceleration is changing you might get away with something about directionless jerk. How is that the same?   If you're saying the Question implies anything about "dark energy" I confess, I wholly missed that, perhaps due to my limited understanding.  Can you re-phrase it for simple people?  
> **username_0**: I'm still none the wiser - if this pedantry is typical, I'm back to Quora! -Moggsy8  
> **username_0**: OK then; searching to find out if cosmic acceleration is changing, the only answer that was clear enough to remember was JERK=1 with comment about dimensionless. All refs I found were 10-20 years old so I assumed this would be well answered by now and only my ignorance of current technical jargon prevented my understanding. Moggsy8.  

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