Published: March 24, 2017
This animation shows Arctic sea ice from minimum in September 2016 through the maximum in March 2017. Credit: NASA.

This week's top research stories include satellite imagery showing that Arctic sea ice was at a record low maximum extent for the third straight year, images of Comet 67P and a new study on prison's effect on gang membership.

Arctic sea ice was at a record low maximum extent for the third straight year, according to scientists at the National Snow and Ice Data Center (NSIDC) and NASA.ÌýThe National Snow and Ice Data Center (NSIDC) is part of theÌýCooperative Institute for Research in Environmental SciencesÌýat ¶¶Òõ¶ÌÊÓƵ Boulder.ÌýThe 2017 Arctic maximum is now the lowest in the 38-year satellite record, beating 2015’s maximum of 14.517 million square kilometers (5.605 million square miles) on Feb.Ìý25, and 2016’s maximum of 14.52 million square kilometers (5.606 million square miles).

Comet 67P full of surprises

Images returned from the European Space Agency's Rosetta mission indicate the surface of comet 67P/Churyumov-Gerasimenko was a very active place during its most recent trip through the solar system, says a new study led by ¶¶Òõ¶ÌÊÓƵ Boulder. The images show the comet's surface is full of growing fractures, collapsing cliffs and massive rolling boulders. Moving material buried some features on the comet’s surface and exhumed others. A study on 67P’s changing surface was released Tuesday in the journalÌýScience.

Gang membership seldom originates in prison, new study suggests

Juvenile offenders are more likely to leave a gang than join one while incarcerated, according to a surprising, first-of-its kindÌýstudyÌýby ¶¶Òõ¶ÌÊÓƵ Boulder criminologist David Pyrooz.ÌýThe study also found that gang membership is highly durable, with members bringing their affiliations into the correctional system from the street and taking it with them when released.