Matter & Energy News -- ScienceDaily

• Interstellar solar sails hit a strange problem at 75% of light speed
  Solar sails pushed by powerful lasers could reach incredible speeds, but relativity may eventually make the light itself work against them. At around 75% of the speed of light, scattered photons can begin creating drag, adding a surprising obstacle to interstellar travel.
• A search for one exotic particle uncovered two strange new structures
  A search for one mysterious particle unexpectedly revealed evidence for two different structures that may belong to the bizarre family of exotic subatomic particles known as XYZ states. The findings could help physicists uncover new ways that quarks and gluons combine to create matter.