Shuttle astronauts attached the S0 truss to the station today.

Two stars have recently been identified by astronomers using the Chandra as being possible quark stars. These have so far just been a theory: that the extreme pressure in neutron stars could break the neutrons down into their constituent quarks.

See also:

• Is RX J185635-375 a Quark Star?
• New Constraints on Neutron Star Cooling from Chandra Observations of 3C58

Hear also: This NPR story on the discovery, which is where I first heard of it.