Galaxy Zoo

Infobox Website
name = Galaxy Zoo



caption =
url = http://www.galaxyzoo.org
commercial = No
type = Volunteer Scientific Project
language = English, Polish
registration = Yes
owner = Galaxy Zoo Team
author = Galaxy Zoo Team
launch date = 12 July 2007
current status =
revenue =

Galaxy Zoo is an online astronomy project which invites members of the public to assist in classifying over a million galaxies. It is an example of Citizen science as it enlists the help of members of the public to help in scientific research. The project is inspired by Stardust@home, where the public was asked by NASA to search images obtained from a mission to a comet for interstellar dust impacts. Galaxy zoo is a collaboration between Oxford University, Portsmouth University, Johns Hopkins University, Yale University and Fingerprint Digital Media, Belfast

Purpose

Galaxy Zoo volunteers are asked to judge from the images whether the galaxies are elliptical or spiral and, if spiral, whether they are rotating in a clockwise or anti-clockwise direction. The images were taken automatically by the Sloan Digital Sky Survey using a digital camera mounted on a telescope at the Apache Point Observatory in New Mexico, United States. It is hoped this census will provide valuable information about how different kinds of galaxies are distributed, allowing scientists to determine whether existing galactic models are correct [cite news | title = Galaxy Zoo opens | publisher = inthenews.com | date = July 11 2007 | url = http://www.inthenews.co.uk/news/autocodes/countries/mexico/galaxy-zoo-opens-$1107870.htm | accessdate = 2007-07-12] . It is an example of citizen science.

Theorists believe that spiral galaxies can merge and become ellipticals, and also that ellipticals can become spirals if they receive more gas or stars. [ [http://www.galaxyzoo.org/Project.aspx Galaxy Zoo - The Science, page 1] ] In addition, Professor Michael Longo of the University of Michigan has claimed that the rotation of spiral galaxies is not random, which would force a major rethink of cosmology if it were correct. This is based on a survey of 1,660 galaxies: a much larger sample could prove or disprove it. [ [http://www.galaxyzoo.org/Project.aspx Galaxy Zoo - The Science, page 2] ]

Importance of volunteers

Computer programs have been unable to reliably classify the galaxies. According to a member of the team behind the project, Kevin Schawinski, "The human brain is actually much better than a computer at these pattern-recognition tasks."cite news | title = See new galaxies — without leaving your chair | publisher = [e-mail] | date = July 11 2007 | url = http://www.nature.com/news/2007/070709/full/070709-7.html | accessdate = 2007-07-12] Without human volunteers, it would take researchers years to process the photographs, but it is estimated that with as few as 10,000 to 20,000 people giving up time to classify the galaxies, the process could be complete in one month. [cite news | title = Astronomers Seek Aid for Galactic Census | publisher = Townhall.com | date = July 11 2007 | url = http://www.townhall.com/News/NewsArticle.aspx?contentGUID=7ae4df34-128f-476c-a1d3-ff05ea5c160c | accessdate = 2007-07-12]

No knowledge of astronomy is required. In the site's tutorial, would-be volunteers are shown spirals, ellipticals etc., and can try guessing before being shown the correct answer. Also shown are pictures of stars and satellite trails, which the robot telescope would have recorded without being able to classify them. Volunteers are then tested on some additional pictures and signed up if they get a reasonable number of correct results.

=Previously unseen

Chris Lintott, another member of the team behind the project commented that, "One advantage is that you get to see parts of space that have never been seen before. These images were taken by a robotic telescope and processed automatically, so the odds are that when you log on, that first galaxy you see will be one that no human has seen before."cite news | title = Scientists seek galaxy hunt help | publisher = BBC News | date = July 11 2007 | url = http://news.bbc.co.uk/1/hi/sci/tech/6289474.stm | accessdate = 2007-07-12] This was confirmed by Schawinski, "Most of these galaxies have been photographed by a robotic telescope, and then processed by computer. So this is the first time they will have been seen by human eyes."cite news | title = See new galaxies — without leaving your chair | publisher = [e-mail] | date = July 11 2007 | url = http://www.nature.com/news/2007/070709/full/070709-7.html | accessdate = 2007-07-12]

Progress

On August 2, 2007, "Galaxy Zoo" issued its first newsletter which explained that 80,000 volunteers had already classified more than 10 million images of galaxies, meeting the goals for the first phase of the project. The aim now is

: To have "each and every galaxy classified by 20 separate users. The importance of multiple classifications is that it will enable us to build an accurate and reliable database, that will meet the high standards of the scientific community. For the first time, we'll be able to separate not only spirals from ellipticals, but obvious spirals from fainter, fuzzier things. No-one has ever been able to do this before. ("Newsletter").

This target was later raised to 30, in light of the continuing enthusiasm of the volunteers. The final datasets contain 34,617,406 clicks done by 82,931 users. Work was then done to test for bias, by presenting images in black-and-white and / or photographically reversed. This is needed to check whether the apparent surplus of anti-clockwise spirals [ [http://www.galaxyzooforum.org/index.php?topic=9454.0 Why record the galaxy rotation?] ] was actually a bias of the human eye (as seems to be the case). [ [http://www.badastronomy.com/bablog/2008/01/10/aas-14-galaxy-zoo-finds-people-are-screwed-up-not-the-universe/ Galaxy zoo finds people are screwed up, not the Universe] ]

There is also an active [http://www.galaxyzooforum.org/ forum] attached to "Galaxy Zoo", where volunteers post the more striking images and discuss what they are. There are already some interesting (unofficial) results. Ring galaxies turn out to be much more common than was believed. Only two known galaxies were 'three legged' - possessing three well-defined spiral arms. A lot more have now been found. [ [http://www.galaxyzooforum.org/index.php?topic=7446.0 three legged well defined spiral galaxy] ] . There are many pictures of merging, colliding or interacting galaxies. [ [http://www.galaxyzooforum.org/index.php?topic=567.0 Biggest cosmic trainwrecks - Mergers] ]

There is also now a 'science blog', [ [http://www.galaxyzooblog.org/ Official Blog of the Galaxy Zoo project] ] , an official summary of what the 'zoo' has achieved so far. There is a current project seening volunteers to review a set of possible merging galaxies. Galaxy Zoo 2 will go live in the near future and offer a much more detailed classification system. [ [http://www.galaxyzoo.org/Default.aspx Galaxy Zoo Homepage] , as at June 8th 2008.]

Discoveries

An object known as _nl. Hanny's Voorwerp [ [http://sciencenews.org/view/generic/id/33436/title/Galaxy_Zoos_blue_mystery_(part_2) Science News / Galaxy Zoo's Blue Mystery (part 2):] ] , Dutch for "Hanny's object", [ [http://news.bbc.co.uk/1/hi/sci/tech/7543776.stm "Teacher finds new cosmic object"] , BBC, 5 August 2008] was spotted by a member called Hanny van Arkel and has attracted some scientific interest. [ [http://www.galaxyzooblog.org/2008/03/20/voorwerp-fever/ Voorwerp fever] and [http://www.galaxyzooblog.org/2008/01/11/whats-the-blue-stuff-below/ What’s the blue stuff below?] ] This discovery was featured as NASA's Astronomy Picture of the Day on June 25, 2008. [cite web |url=http://apod.nasa.gov/apod/ap080625.html |title=What is Hanny's Voorwerp? |accessdate=2008-06-25 |work= Galaxy Zoo Project, ING |date= 2008-06-25]

References

External links

* [http://www.galaxyzoo.org/ Galaxy Zoo]
* [http://www.galaxyzooforum.org/ Galaxy Zoo Forum]
* [http://www.galaxyzooblog.org/ The official blog of the Galaxy Zoo project]
* [http://galaxyzoo.wordpress.com/ Original Blog of the most interesting galaxies found on Galaxy Zoo] superseded by the official blog above
* [http://cas.sdss.org/astro/en/tools/places/ Sloan Digital Sky Survey - Famous Places]
* [http://galaxyimages.blogspot.com/ Another blog of images from the Sloan Digital Sky Survey]
* [http://hitzradiouk.com/galaxyzoo/ Radio station featuring interviews from the team]
* [http://arxiv.org/abs/0803.3247 Galaxy Zoo: The large-scale spin statistics of spiral galaxies in the Sloan Digital Sky Survey] (Astrophysics paper, downloadable)
* [http://arxiv.org/abs/0804.4483 Galaxy Zoo : Morphologies derived from visual inspection of galaxies from the Sloan Digital Sky Survey] (Astrophysics paper, downloadable)
* [http://arxiv.org/abs/0805.2612 Galaxy Zoo: the independence of morphology and colour] (Astrophysics paper, downloadable)