Exploring Galaxy Zoo

by Muhammad Alfian Rasyidin

Do you like to see amazing pictures? Have fun while learning about space? Galaxy Zoo, Zooniverse’s first project, is the best site for you! It is absolutely incredible. You’ll see millions of beautiful pictures of galaxies that we can’t see with our naked eyes. While learning about space, you’ll also help astronomers find the answer to one of biggest questions in astronomy: “How do galaxies form?”

Galaxy Zoo started in 2007, and since then, astronomers have posted millions of images taken by Sloan Digital Sky Survey. Visitors look at images of galaxies and give simple responses about the shape of those galaxies. Don’t worry if you don’t have any ideas about the shapes of galaxies. This site offers you a tutorial so that you can easily follow along with the questions that are being asked. In the past, the task was slightly simpler than it is today, but now they can capture images with higher resolution, which means the images on the site have more details.

Some of you might ask why astronomers need your help. Just simply, people are much better than computers at interpreting images. Also, another reason they need help because a single astronomer would take years to classify those images. Let’s do a simple math problem to find how many years that would probably take. Suppose that we have 10 millions images and we hire a person to work on 1,000 images to be classified daily:

Total Time    = numbers of images / numbers classifications daily

                       = 10,000,000 / 1,000 = 10,000 days

                       = 10,000 days / 365 days per year = Approx. 27.4 Years

Surprisingly, Galaxy Zoo does a lot better than the 1000 images one person could do daily. In fact, the site got 70,000 classifications within 24 hours after this site launched. Let’s take a look to site’s statistics.


In the bar graph above, it shows daily total classifications in the fourth week of March 2015. We can see that on March 24th and 25th, there were more than 30,000 classifications done daily, but as the week goes on the number decrease to just 10,000 classifications, so on average approximately 20,000 classifications done by users daily. Peak classifications, like those on March 24th and 25th, are usually because a new blog post has just been posted, which is usually published in the beginning of the week.

So from the graph above, it proves that a lot of people can do this work much faster than only a single person. Let’s find how much time do they need if you, the citizen scientist, can help them on classifying those images. Let’s take ~20,000 classifications done daily:

Total Time    = numbers of images / average daily classifications

                       = 10,000,000 / 20,000 = 500 days

                       = 500 days / 365 days per year = Approx. 1.4 Years

You can see that it is about 20 times faster! That is why, astronomers need YOU! Those facts already prove to you that being involved in citizen science is fantastic. As this project isn’t only popular, but also educational.

So what are you waiting for? Click this link to get started and explore Galaxy Zoo!



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