Mapping spiral structure on the far side of the Milky Way.

Little is known about the portion of the Milky Way lying beyond the Galactic center at distances of more than 9 kiloparsec from the Sun. These regions are opaque at optical wavelengths because of absorption by interstellar dust, and distances are very large and hard to measure. We report a direct trigonometric parallax distance of kiloparsec obtained with the Very Long Baseline Array to a water maser source in a region of active star formation.

Supernova--remnant origin of cosmic rays?

It is thought that Galactic cosmic-ray nuclei are gradually accelerated to high energies (up to about 300 TeV per nucleon, where 1 TeV is 10(12) eV) in the expanding shock waves connected with the remnants of powerful supernova explosions. However, this conjecture has eluded direct observational confirmation since it was first proposed in 1953 (ref. 3).