The first observer to catalog differences in star brightnesses was Greek astronomer Hipparchus. He created a catalog around 135 B.C.E. of roughly 850 stars divided into six ranges. He called the ...

Often in these weekly Night Sky columns I refer to the magnitude of a star or planet. The concept of magnitude is relatively easy to grasp. Put simply, magnitude indicates an object’s degree of ...

An earthquake rattled much of the Northeast on Friday morning, with shaking felt across the New York City metropolitan area and in communities from Baltimore and Philadelphia up through New England.

William Menke, a seismologist at the Lamont-Doherty Earth Observatory of Columbia University, explains. The Richter scale was developed in 1935 by American seismologist Charles Richter (1891-1989) as ...