by Ann » Wed Nov 06, 2019 6:06 am
Some Pinwheel galaxy facts:
1) It is
HUGE. It is estimated to be 170,000 light-years in diameter.
Wikipedia claims that the diameter of the Milky Way is much wider, 258,000 light-years. Don't believe Wikipedia! The diameters of the Milky Way and M101 have been estimated using different methods.
NASA, by contrast, wrote that the diameter of M101 is nearly twice the diameter of the Milky Way.
2) M101 contains
stars like all the grains of sand of the Earth. Both Wikipedia and NASA agrees that M101 contains over a
trillion stars, twice the number of the Milky Way, according to Wikipedia.
3) It is
lopsided. Tidal forces are tugging at it.
4) It is
BLUE!!! Its B-V index, +0.45, is amazingly blue for a large, let alone ultra-large galaxy!
5) It is chock full of
emission nebulas! My word!
6) So M101 is like a galaxy out of the Universe's youth, when galaxies went bananas and formed stars like crazy. The only galaxy that I can think of that is a little bit like it is M99, but I do know that M99 is less blue than M101, and I'm almost certain that it is smaller than M101 and contains fewer stars. I agree that M99 is lopsided just like M101, however!
M101. Photo: Adam Block/Mount Lemmon SkyCenter.
M99. Photo: Adam Block/Mount Lemmon SkyCenter.
Ann
Some Pinwheel galaxy facts:
1) It is [b][size=200]HUGE[/size][/b]. It is estimated to be 170,000 light-years in diameter. [url=https://en.wikipedia.org/wiki/Pinwheel_Galaxy#Structure_and_composition]Wikipedia[/url] claims that the diameter of the Milky Way is much wider, 258,000 light-years. Don't believe Wikipedia! The diameters of the Milky Way and M101 have been estimated using different methods. [url=https://www.nasa.gov/feature/goddard/2017/messier-101-the-pinwheel-galaxy]NASA[/url], by contrast, wrote that the diameter of M101 is nearly twice the diameter of the Milky Way.
2) M101 contains [b][size=150][color=#FFBF80]stars like all the grains of sand[/color][/size][/b] of the Earth. Both Wikipedia and NASA agrees that M101 contains over a [b][size=150]trillion[/size][/b] stars, twice the number of the Milky Way, according to Wikipedia.
3) It is [b][size=130]l[sup]o[/sup]p[sub]s[/sub]i[sup]d[/sup]e[sub]d[/sub][/size][/b]. Tidal forces are tugging at it.
4) It is [b][size=150][color=#0080FF]BLUE[/color][/size][/b]!!! Its B-V index, +0.45, is amazingly blue for a large, let alone ultra-large galaxy!
5) It is chock full of [b][size=150][color=#FF00FF]emission nebulas[/color][/size][/b]! My word!
6) So M101 is like a galaxy out of the Universe's youth, when galaxies went bananas and formed stars like crazy. The only galaxy that I can think of that is a little bit like it is M99, but I do know that M99 is less blue than M101, and I'm almost certain that it is smaller than M101 and contains fewer stars. I agree that M99 is lopsided just like M101, however!
[float=left][img2]https://upload.wikimedia.org/wikipedia/commons/thumb/f/f6/M101_Galaxy_from_the_Mount_Lemmon_SkyCenter_Schulman_Telescope_courtesy_Adam_Block.jpg/1024px-M101_Galaxy_from_the_Mount_Lemmon_SkyCenter_Schulman_Telescope_courtesy_Adam_Block.jpg[/img2][c][size=85]M101. Photo: Adam Block/Mount Lemmon SkyCenter.[/size][/c][/float][float=right][img2]https://upload.wikimedia.org/wikipedia/commons/9/97/M99s.jpg[/img2][c][size=85]M99. Photo: Adam Block/Mount Lemmon SkyCenter.[/size][/c][/float]
Ann