A nebula is a giant cloud of gas (mostly hydrogen and helium) and cosmic dust situated between stars in the interstellar medium. Nebulae serve as sites of stellar birth and death—including emission nebulae that glow from ionized gas, reflection nebulae that scatter starlight, and dark nebulae that obscure background stars.
Source: science.nasa.gov
31/05/2017
What would it look like to approach the Bubble Nebula? Blown by the wind and radiation from a massive star, this bubble now spans seven light-years in diameter. The hot star inside is thousands of times more luminous than our Sun, and is now offset from the nebula's center. The visualization starts with a direct approach toward the Bubble Nebula (NGC 7635) and then moves around the nebula while continuing the approach. The featured time-lapse visualization is extrapolated from images with the orbiting Hubble Space Telescope and the WIYN telescope on Kitt Peak in Arizona, USA. The 3D-computer model on which this visualization is based includes artistic interpretations, and distances are significantly compressed.