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 ...

If someone asks you, “How bright is that star?” and your answer is “Pretty bright,” that isn’t very useful. And, of course, it’s worthless for any type of comparative research. So for centuries, ...

There are a number of ways to measure the magnitude of an earthquake. Most scales are based on the amplitude of seismic waves recorded on seismometers. These scales account for the distance between ...

Earthquake occurrence is notoriously difficult to predict. While some aspects of their spatiotemporal statistics can be relatively well captured by point-process models, very little is known regarding ...

I.—APPARENT MAGNITUDES: (a) VISUAL.THE magnitude of a star, as determined by direct astronomical observation, is a measure of its apparent brightness on a scale which has been precisely defined only ...

What is the baseline for determining the magnitude scale of celestial objects? Why do brighter objects have negative numbers? Dean Treadway Knoxville, Tennessee The first observer to catalog ...