The notion that fake news exists in its own universe turns out to be doubly true: One universe is the realm outside truth. The other is its own seedy pocket of social media.

In a new study published Thursday in the journal Science, political scientists surveyed the inhabitants of this Internet pocket around the time of the last presidential election, from Aug. 1 to Dec. 6, 2016. They found that people who shared fake news were more likely to be older and more conservative. “Super-sharers” were responsible for the bulk of fake news, soaking their Twitter feeds in falsehoods with the gusto of kids with water pistols. They were enthusiastic communicators, tweeting an average of 70 times a day, and had a very limited reach.

Only 0.1 percent of users shared 80 percent of the fake news. “And almost all exposure is among 1 percent of Twitter users,” said David Lazer, a political-science professor at Northeastern University and an author of the new report. The algorithm that researchers designed to sniff out fake news — using a list of offending publishers, like Truthfeed.com, compiled by academics, journalists and fact-checkers — could not detect any fake news in the feeds of about 90 percent of users.