Behold: the face-on spiral of M33, aka the Pinwheel Galaxy, aka The Triangulum Galaxy. To wit:
M33 is over 50,000 light-years in diameter, third largest in the Local Group of galaxies after the Andromeda Galaxy (M31), and our own Milky Way. About 3 million light-years from the Milky Way, M33 is itself thought to be a satellite of the Andromeda Galaxy and astronomers in these two galaxies would likely have spectacular views of each other’s grand spiral star systems. As for the view from planet Earth, this sharp image shows off M33’s blue star clusters and pinkish star forming regions along the galaxy’s loosely wound spiral arms. In fact, the cavernous NGC 604 is the brightest star forming region, seen here at about the 7 o’clock position from the galaxy center. Like M31, M33’s population of well-measured variable stars have helped make this nearby spiral a cosmic yardstick for establishing the distance scale of the Universe.
(Image: Rui Liao)
Behold: the splendid spiral galaxy M33 – a trifling 3 million light years away, it’s also known as the Triangulum Galaxy. To wit:
The galaxy’s inner 30,000 light-years or so are shown in this magnificent 25 panel telescopic mosaic. Based on image data from space and ground-based telescopes, the portrait of M33 shows off the galaxy’s reddish ionised hydrogen clouds or HII regions. Sprawling along loose spiral arms that wind toward the core, M33’s giant HII regions are some of the largest known stellar nurseries, sites of the formation of short-lived but very massive stars. Intense ultraviolet radiation from the luminous, massive stars ionises the surrounding hydrogen gas and ultimately produces the characteristic red glow. To enhance this image, broadband data were used to produce a colour view of the galaxy and combined with narrowband data recorded through a hydrogen-alpha filter. That filter transmits the light of the strongest visible hydrogen emission line.
Huge image here (caution: you will tend to feel insignificant in the Grand Scheme.)
(Image: Subaru Telescope (NAOJ), Hubble Space Telescope – Image Processing: Robert Gendler. Additional Data: BYU, Robert Gendler, Johannes Schedler, Adam Block – Copyright: Robert Gendler, Subaru Telescope, NAOJ)