Comments on: Measuring Light

By: Phil

Phil — Thu, 12 Aug 2010 13:01:38 +0000

Have a better look at http://en.wikipedia.org/wiki/IceCube#Point_Sources_of_High_Energy_Neutrinos (and also follow the link to the Pierre Auger observatory). It will convince you that there are other extra-galactic probes than light.

By: JJG

JJG — Sat, 24 Jul 2010 21:13:24 +0000

Good point! There’s cosmic rays that seem to be coming from local supernovae, neutrinos and gravitational waves. But when I talked about “distant space” I was referring to the 99.9999% of space that’s outside of our little Galaxy. So far the only messenger that we can interpret that covers these distances are photons, i.e., light.

By: Phil

Phil — Tue, 20 Jul 2010 12:03:47 +0000

It’s not entirely true that “all our knowledge about distant space comes from measuring light that is emitted by far-away astronomical objects”. Most of it, yes, but not all: we can also measure fluxes of other kinds of particles, like protons and anti-protons, electrons and positrons, and, perhaps more interestingly since they don’t loose memory from where they come from, neutrinos (see for example http://en.wikipedia.org/wiki/IceCube ).