RocketSTEM Issue #11 - April 2015 | Page 5

Celestial fireworks mark Hubble’s 25th The brilliant tapestry of young stars flaring to life resemble a glittering fireworks display in the 25th anniversary Hubble Space Telescope image, released to commemorate a quarter century of exploring the solar system and beyond. “Hubble has completely transformed our view of the universe, revealing the true beauty and richness of the cosmos” said John Grunsfeld, astronaut and associate administrator of NASA’s Science Mission Directorate. “This vista of starry fireworks and glowing gas is a fitting image for our celebration of 25 years of amazing Hubble science.” The sparkling centerpiece of Hubble’s anniversary fireworks is a giant cluster of about 3,000 stars called Westerlund 2, named for Swedish astronomer Bengt Westerlund who discovered the grouping in the 1960s. The cluster resides in a raucous stellar breeding ground known as Gum 29, located 20,000 light-years away from Earth in the constellation Carina. To capture this image, Hubble’s near-infrared Wide Field Camera 3 pierced through the dusty veil shrouding the stellar nursery, giving astronomers a clear view of the nebula and the dense concentration of stars in the central cluster. The cluster measures between 6 and 13 light-years across. The giant star cluster is about 2 million years old and contains some of our galaxy’s hottest, brightest and most massive stars. The nebula reveals a fantasy landscape of pillars, ridges and valleys. The pillars, composed of dense gas and thought to be incubators for new stars, are a few light-years tall and point to the central star cluster. Other dense regions surround the pillars, including reddish-brown filaments of gas and dust. The brilliant stars sculpt the gaseous terrain of the nebula and help create a successive generation of baby stars. When the stellar winds hit dense walls of gas, the shockwaves may spark a new torrent of star birth along the wall of the cavity. The red dots scattered throughout the landscape are a rich population of newly-forming stars still wrapped in their gas-anddust cocoons. Because the cluster is very young – in astronomical terms – it has not had time to disperse its stars deep into interstellar space, providing astronomers with an opportunity to gather information on how the cluster formed. Credit: NASA, ESA, the Hubble Heritage Team (STScI/AURA), A. Nota (ESA/STScI), and the Westerlund 2 Science Team.