This is not the oldest planet in the universe. It's just the oldest we've found so far, and really, really old.
Existence of earth-like companions is by no means a foregone conclusion. As this world was formed from (mostly) primordial material, it would be composed of hydrogen, helium, and lithium, and almost nothing else (as these were the elements formed in the "big bang nucleosynthesis" (condensation of nuclei shortly after the big bang)). It could be gas all the way through - we don't know. Model of available materials says it's almost all gas, while models of gas giant formation say that they need a rocky core to form. My money's on the planet-formation model being off, as there's strong circumstantial evidence for our models of element distribution from the initial synthesis.
Existence of life is extremely unlikely, as it requires heavy elements in at least trace amounts, as far as we know.
Heavy element synthesis by supernovae would not have occurred substantially, as the massive stars that burned out that soon after formation would have had their heavy-element cores swallowed during collapse into the resulting black hole (only less massive supernovae produce neutron stars). The shell blown off would be mostly hydrogen and helium.
So, the real puzzle is how a planet formed from only the primordial elements.
Planet mass is about 2.5 that of Jupiter, but that's a nit-pick.
I hope this is interesting to at least a few people reading }:>. Subject came up and was discussed at length on slashdot a little while ago.
A few points of clarification:
Existence of life is extremely unlikely, as it requires heavy elements in at least trace amounts, as far as we know.
Heavy element synthesis by supernovae would not have occurred substantially, as the massive stars that burned out that soon after formation would have had their heavy-element cores swallowed during collapse into the resulting black hole (only less massive supernovae produce neutron stars). The shell blown off would be mostly hydrogen and helium.
So, the real puzzle is how a planet formed from only the primordial elements.
I hope this is interesting to at least a few people reading }:>. Subject came up and was discussed at length on slashdot a little while ago.