When we see pictures of galaxies outside the Milky Way, what we're usually looking at is primarily the light of their stars. But stars are far from the only ingredient that makes up a galaxy. Think of stars as the chunks of vegetables in the galactic
The broth, then, in which they float, is the intergalactic medium – not empty space but filled with often tenuous, sometimes dense clouds of dust and gas that drift between the stars. Because stars are so much brighter, the dust is usually second fiddle; but that dust, from which stars are born, to which stars return, can tell us a lot about the structure and activity within a galaxy.
New stars being born incorporate the dust from dead stars, making each subsequent generation of stars slightly different. We are, indeed, allBut the dust isn't uniformly distributed. Stellar winds, galactic winds, and the effects of gravity can all push and sculpt interstellar dust into complex shapes filled with cavities. Mapping the structures and the composition of the elements within them is a crucial tool for understanding the formation of… well… pretty much everything.
The new images, unveiled at the 240th meeting of the American Astronomical Society, were obtained by the operated by the European Space Agency between 2009 and 2013. Until the launch of Webb – which has yet to deliver its first science images – Herschel was the largest infrared telescope ever to be launched.Like Webb, its ultracold operating temperature meant that Herschel could peer into the far-infrared, imaging some of the coldest and dustiest objects in space, down to temperatures around -270 degrees Celsius .
It was less adept at detecting more diffuse dust and gas, however. To fill in the gaps, a team of astronomers led by Christopher Clark of the Space Telescope Science Institute used data from three other retired telescopes: ESA's