Readers wonder about a hydrogen wall, pig lung transplants and more
Your letters and comments on the September 15, 2018 issue of Science News
Wonderwall
An ultraviolet glow spotted by NASA’s New Horizons spacecraft may signal a hydrogen wall that separates the solar system from the rest of the Milky Way galaxy, Lisa Grossman reported in “New Horizons may have seen a glow at the solar system’s edge” (SN: 9/15/18, p.