Obstacles to observing the cosmic neutrino background

[bobsmith76]

I was delight to learn that there was an event about 1 μs after the Big Bang when neutrinos decoupled, making them in principle observable. We of course don't have the technology to observe the event now, but the lecturer who informed me of this said it might be available 200 years from now. What are the physical obstacles to observing such an event, and do you think it will ever be observed.

 

[mfb]

- the neutrinos have a low energy by now (I don't know the value by heart, but you can find it somewhere). In general, the cross-section tends to increase with energy.
- the neutrino background density is probably low
- there are a lot of neutrinos from stars as background source

"200 years from now" = "it could be possible, but I don't see any way to do it"