Changes

* 1987: A supernova was detected in the relatively nearby Large Magellanic Cloud by an astronomer at Chile's Las Campanas Observatory; because it is so close (and actually visible to the naked eye), it became the object of intense study.

* 1987: A supernova was detected in the relatively nearby Large Magellanic Cloud by an astronomer at Chile's Las Campanas Observatory; because it is so close (and actually visible to the naked eye), it became the object of intense study.

* 1954: The first mass inoculation of children against poliomyelitis took place, in Pittsburgh, {{Directory: Pennsylvania|Pa.]], testing the vaccine developed by Jonas Salk.

* 1954: The first mass inoculation of children against poliomyelitis took place, in Pittsburgh, [[Directory: Pennsylvania|Pa.]], testing the vaccine developed by Jonas Salk.

* 1848: John Quincy Adams, the former president of the [[Directory:United States of America|United States]], died at the U.S. Capitol, where he collapsed at his desk from a stroke; he had served in the House of Representatives since 1831.

* 1848: John Quincy Adams, the former president of the [[Directory:United States of America|United States]], died at the U.S. Capitol, where he collapsed at his desk from a stroke; he had served in the House of Representatives since 1831.