This Is The Milky Way Galaxy’s Big Brother


Meet UGC 12158. Or as he calls himself in bars to pick up chicks, Biggie Spiral. You’ll notice a resemblance between Biggie and our favorite galaxy: Sir Milky Way. Namely, that they’re both gorgeous spiral galaxies. Phil Plait, who has worked with Hubble images for years, decided to crunch the numbers on this gorgeous galaxy:

So I went to the release page for it, and when I saw the distance, I was shocked: that galaxy’s not big, it’s freaking  huge.  I figured it was part of the Virgo cluster, maybe, 60 million light years away or so. Nope: it’s a whopping  400 million light years distant, which is a long, long haul. That was stunning to me; if it’s that far away the galaxy really has to be a bruiser. So I grabbed a raw image from the Hubble archive and measured its size in pixels, which I could then convert to a spatial size given its distance.

And I can still hardly accept this, but UGC 12158 is  140,000 light years across. I measured it twice, two different ways, to be sure. That’s the biggest spiral I’ve ever heard of! Mind you, the Milky Way is in the top tier of galaxies in the entire Universe when it comes to size, but UGC 12158 whips us by a clean 40%!.

Good lord. I had no idea that the Milky Way Galaxy was an impressively sized galaxy until Phil Plait dropped that knowledge bomb on me. But still!, this galaxy is 40% bigger? Brain. Doesn’t compute. Wants to, but cannot.