A pink aurora over Yellowknife in the North West Territories of Canada …
… taken by Yakchi Takasaka (see www.spaceweather.com Sept 15th). The pink colour is probably a sign of nitrogen. Most auroras are green – caused by energetic particles hitting oxygen atoms in the high atmosphere. Pink aurora occur as particles descend lower than usual striking nitrogen molecules.
Meanwhile, at https://phys.org/print424600861.html … astronomers are looking into the origin of Planet 9 (given a less exotic location), while at https://phys.org/print424874419.html … we have a new theory on the origin of the asteroid belt. Finally, at https://phys.org/print424605717.html …. researchers at the University of York have shown that molecules reaching Eath via meteorites could potentially be ancestral to the building blocks of DNA.