Two giant galaxies combine to form a massive ellipse.
A frog declared extinct nearly two decades ago reappears in Israel.
A life-threatening disease emerges in Botswana from mongoose hosts.
Planet-forming particles swarm an unlikely star host.
After 17 years underground, red-eyed Brood II cicadas emerge.
A breakthrough technique delivers a see-through brain.
Plentiful ice in the Saturn system hints at its age.
Diversity in algae-eating fish protects coral from toxic seaweed.
More carbs in our diet helped harmful oral microbes to succeed.
Astronomers measure how fast a black hole spins.