NASA launched the Hubble Space Telescope 26 years ago on April 24, 1990. In celebration they decided to give us this birthday present.
The image is of the Bubble Nebula (NGC 7635). The bright star inside the blue bubble is a raging inferno that emits a solar wind of hot gases moving at 4 million miles per hour. Contact between the hot expanding gases and the cold gases in interstellar space creates the outer edge of the bubble. When oxygen is hot enough it emits the blue light seen in the image.
The bubble is seven light-years in diameter. (!!) That’s roughly 1.5 times the distance between our sun and Alpha Centauri, the star closest to our solar system. The star that is creating the bubble is 45 times as massive as the sun.
If you think the picture is amazing, check out this video.