Have WISPs been observed anywhere prior to their attribution to dark matter or are these theoretical particles that are thought to describe dark matter?

We haven't seen them anywhere, the only real reason we think/hope they might exist is for dark matter. If they do exist we might find them in a particle collider, but so far there's no sign of them there either.

Oh, , here goes with the armchair expert and his pronunciamentos!

1. Balance- Asymmetry in the Big Bang, a miniscule initial difference that magnified over time

A very natural consequence of the pursuit of mathematical or theoretical beauty being misleading. Nothing is perfectly symmetric over time!

2. Dark matter- forget WIMPs, think neutrinos! Lots and lots of neutrinos!

3. Expansion- Something's wrong with the standard candle! In fact it would be quite surprising if symmetric expansion was proceeding uniformly! More likely not!

Okay that's that. All is solved satisfactorily. Tea time! Oi! My crumpet is not round!

We haven't heard the last from neutrinos, that's for sure...

My pet theory is we've missed something important about the very early universe. There's plenty we don't really understand about the Big Bang and what came after, though some physicists will tell you they are very confident they do know!

Re. Hubble constant - should it be called the Hubble parameter? Wikipedia says "Current evidence suggests that the expansion of the universe is accelerating (see Accelerating universe), meaning that for any given galaxy, the recession velocity dD/dt is increasing over time as the galaxy moves to greater and greater distances; however, the Hubble parameter is actually thought to be decreasing with time, meaning that if we were to look at some fixed distance D and watch a series of different galaxies pass that distance, later galaxies would pass that distance at a smaller velocity than earlier ones".

Another question - the units "km/s/Mpc" can be simplified by removing the "distance/distance" which cancel each other out algebraically, leaving "1/s", (Hertz). Which is an odd way to think about it - the Hubble parameter is some incredibly small number of Hertz. Which means it's also a frequency and therefore a musical note. Music of the spheres? But what I'm really wondering about is - if you take the inverse (the amount of time it would take for one complete cycle of that frequency) you get a value that is very close to the age of the universe. Is this just a coincidence or does it Mean Something? The crackpot theory that the value of the Hubble parameter is the inverse of the age of the universe is contradicted if the expansion of the universe is accelerating, but consistent with "the Hubble parameter is actually thought to be decreasing with time".

Have WISPs been observed anywhere prior to their attribution to dark matter or are these theoretical particles that are thought to describe dark matter?

We haven't seen them anywhere, the only real reason we think/hope they might exist is for dark matter. If they do exist we might find them in a particle collider, but so far there's no sign of them there either.

Thanks for the reply!

Oh, , here goes with the armchair expert and his pronunciamentos!

1. Balance- Asymmetry in the Big Bang, a miniscule initial difference that magnified over time

A very natural consequence of the pursuit of mathematical or theoretical beauty being misleading. Nothing is perfectly symmetric over time!

2. Dark matter- forget WIMPs, think neutrinos! Lots and lots of neutrinos!

3. Expansion- Something's wrong with the standard candle! In fact it would be quite surprising if symmetric expansion was proceeding uniformly! More likely not!

Okay that's that. All is solved satisfactorily. Tea time! Oi! My crumpet is not round!

We haven't heard the last from neutrinos, that's for sure...

My pet theory is we've missed something important about the very early universe. There's plenty we don't really understand about the Big Bang and what came after, though some physicists will tell you they are very confident they do know!

Re. Hubble constant - should it be called the Hubble parameter? Wikipedia says "Current evidence suggests that the expansion of the universe is accelerating (see Accelerating universe), meaning that for any given galaxy, the recession velocity dD/dt is increasing over time as the galaxy moves to greater and greater distances; however, the Hubble parameter is actually thought to be decreasing with time, meaning that if we were to look at some fixed distance D and watch a series of different galaxies pass that distance, later galaxies would pass that distance at a smaller velocity than earlier ones".

Another question - the units "km/s/Mpc" can be simplified by removing the "distance/distance" which cancel each other out algebraically, leaving "1/s", (Hertz). Which is an odd way to think about it - the Hubble parameter is some incredibly small number of Hertz. Which means it's also a frequency and therefore a musical note. Music of the spheres? But what I'm really wondering about is - if you take the inverse (the amount of time it would take for one complete cycle of that frequency) you get a value that is very close to the age of the universe. Is this just a coincidence or does it Mean Something? The crackpot theory that the value of the Hubble parameter is the inverse of the age of the universe is contradicted if the expansion of the universe is accelerating, but consistent with "the Hubble parameter is actually thought to be decreasing with time".