New Hubble view of the Lagoon Nebula

More precise observations of pulsating Cepheid variable stars confirms a major discrepancy in values of the Hubble constant.

Galaxy clusters are often described by superlatives. After all, they are huge conglomerations of galaxies, hot gas, and dark matter, representing the largest structures in the universe held together by gravity. New observations of the galaxy cluster SPT-CLJ2344-4243 (or Phoenix Cluster) at X-ray, ultraviolet, and optical wavelengths are helping astronomers better understand this extraordinary system.

Records are made to be broken, as the expression goes, but rarely are records left so thoroughly in the dust. Stunned astronomers have witnessed a cosmic explosion about 200 times more powerful than a typical supernova — events which already rank amongst the mightiest outbursts in the universe — and more than twice as luminous as the previous record-holding supernova.