Introducing species to change ecosystems is a balancing act

Species hold ecosystems in a delicate balance. From time to time humans introduce non-native species to an ecosystem, because they may be needed for domestic work, as pets, for carrying loads or even for killing previously ...

Classic portrait of a barred spiral galaxy

(PhysOrg.com) -- The NASA/ESA Hubble Space Telescope has taken a picture of the barred spiral galaxy NGC 1073, which is found in the constellation of Cetus (The Sea Monster). Our own galaxy, the Milky Way, is a similar barred ...