Power of Many

Today’s post comes from Benne Holwerda, an astronomer based at ESA-ESTEC in the Netherlands.  Along with Bill Keel, Benne will be working on science focused on the background galaxies identified as part of the Andromeda Project.  Benne writes today with a personal perspective on the remarkable response we’ve received for the Andromeda Project.

The underlying idea of Zooniverse projects is that many people working together can tackle problems that no single individual, no matter how good a specialist, can do themselves.  I understood this on a conceptual level but the Andromeda Project brought it home in numbers and in person.

Seven years ago, I did my PhD on identifying background galaxies through foreground spiral galaxies in Hubble Space Telescope images. Sound familiar? You are doing the same! The total number of galaxies I identified in these HST images –half real and half artificial for calibration– was on the order of two thousand. It took me 2 years. The Andromeda Project just found the same number of galaxies behind Andromeda in a week!

One of the big perks of being a professional astronomer is that sometimes something literally awesome, as in you are awestruck, comes along: a new insight, a stunning image, a new discovery. For me, the ability of the Andromeda Project to identify a thousand little galaxies behind Andromeda in a mere week is one. It nailed me to my seat. Wow.

Notable Background Galaxy in the Andromeda Project

One of the numerous background galaxies seen in the Andromeda Project. This notable elliptical is enclosed in faint shells, likely produced through galaxy mergers.

Now, the best part: I get to play with those background galaxies!

Originally, I looked for background galaxies because I used their number to estimate how much interstellar dust spiral galaxies had on average. It worked fine at the time, but new observations by the Herschel Space Observatory are far more accurate now. Similarly, we have a good general map of dust in Andromeda from Herschel.  I’ll look (if only for my own personal enjoyment), but their total number will not reveal much new information. But each individual galaxy might tell us something that the Herschel observations cannot: the small scale structure of dust in Andromeda. Bill Keel blogged about this last week.  You pointed us to where they are, which ones are the biggest, and commented if you saw what looked like dust in front of them.

All in a week.


2 responses to “Power of Many”

  1. Jean Tate says :


    Doubly so, because that shell elliptical is in one of the very first images I got to classify; triply so because I even gave it the hashtag “shellelliptical”!!

    And it may turn out that, in another of the images I got to classify, there is a fairly large background galaxy partly obscured by dust, just like IC4633 (featured in Bill Keel’s blog) … only the dust is in M31, at a distance of ~780 kpc!


    And I am but one AP zooite among hundreds (thousands), all discovering these sorts of amazing objects, every day.

    • Sakib says :

      Ah but what are the coordinates of this strange and beautiful galaxy? Shell ellipticals are amazing, I have a feeling we’ll be seeing lots of images of them this year. 🙂

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