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Episode 10: An Un-peculiar Trio of Galaxies?

6 Aug 2009, 04:00 UTC
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Hubble's exquisite resolution reveals details of astronomical objects that have never before been seen. Often, these observations unmask the complex inner workings that help explain previous puzzles as well as lead to new questions. In the case of the so-called "peculiar" trio of galaxies named Arp 274, however, Hubble's clarity showed the situation to look simpler than suspected. Visual inspection shows some normal beautiful spiral galaxies that we've come to expect. It requires deeper investigation into the positions of these galaxies, as well as an exploration of redshift and Doppler shift, to show that this trio might really be considered strange after all. Join us, as we delve into and behind the picture that you, the public, chose to observe.

Hubble press release:

Hubble Celebrates the International Year of Astronomy with the Galaxy Triplet Arp 274
Hubble's Next Discovery, You Decide


The initial voting for Hubble's Next Discovery seemed to be overwhelming. We received over 400,000 votes in just a few days. However, one object had garnered a large majority of the votes, and that made us suspicious. It turns out that someone found and exploited a flaw in our voting procedure to cast continuous votes all day long. After we fixed the code and removed the duplicated votes, we ended up with about 140,000 votes cast. The eventual winner did win by a wide margin, but we are fairly confident that the vote reflected the voice of the people.

Another prominent NASA vote was held on the internet around the same time. NASA asked the public to vote on suggested names, or even suggest a different name, for a new module on the space station. The fans of Stephen Colbert flooded that vote, and his name became the top vote getter. Still, NASA kept the rules flexible enough to choose the name they wanted, and instead named a treadmill after Colbert.

Yet a third public vote was run by the folks over at NASA Edge. In a takeoff on March Madness, they ran a Mission Madness bracket of 64 NASA missions. Folks were asked to vote on "the greatest NASA mission of all time." The rules allowed for the "vote early, vote often" strategy, and the contest was quickly hijacked by competing factions of internet groups, each vying to make their selected mission win. The truly great NASA missions, such as Apollo 11 and Hubble, didn't stand a chance. The eventual winner was a mission I had never heard about before the contest. Such are the lessons of internet voting.

Measuring distance in the universe sounds like a basic and simple task. Most folks assume that astronomers know the distance to all astronomical objects. However, that is not at all true. Measuring accurate distances is a fundamental exercise in astronomy, but it is also very difficult. We can measure exact distances across our solar system and out to the nearest stars. Beyond that, we have developed many ways to estimate larger distances based upon the known distances. Each level of distance in the universe generally relies on calibration by distances to closer objects. We call this the "distance ladder," as one must work through the various estimates to climb from stars to star clusters to nearby galaxies to galaxy clusters to galaxies stretching across the universe.

The image of Arp 274 from the Arp catalog is used in this video podcast with the kind permission of Dr. Halton Arp.

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