Claudius Ptolemy

Claudius Ptolemy was a Greek mathematician, astronomer and geographer who lived in the Egyptian city of Alexandria while under the rule of the Roman Empire. Much of medieval astronomy and geography …Powered by...

A supergiant star’s expanding mystery

Astronomers from Chalmers University of Technology, Sweden, have discovered a huge expanding bubble of gas and dust surrounding a red supergiant star. It’s the largest structure of its kind ever seen …Powered by...