How was the Algol binary system considered strange or paradoxical?
The Algol binary system is considered strange or paradoxical because of its unusual behavior related to its eclipsing nature. Algol consists of two stars, a larger one (Algol A) and a smaller one (Algol B), orbiting around a common center of mass.
Normally, in a binary star system, both stars would orbit each other at a relatively constant distance. However, Algol exhibits a peculiar behavior where Algol B periodically passes in front of Algol A, causing the system to dim significantly. This event is known as an eclipse.
What makes Algol's behavior paradoxical is that the eclipse causes a drop in brightness that is greater than expected. In most binary systems, the brightness decreases by a certain amount when the smaller star passes in front of the larger one. However, in the case of Algol, the brightness can drop by up to two-thirds during an eclipse.
This paradox was resolved when scientists discovered that Algol is actually a triple star system. The third star, Algol C, is much smaller and dimmer than Algol A and Algol B. Algol C's gravitational pull causes the entire system to wobble, resulting in the observed abnormal brightness during eclipses.
Therefore, the strangeness and paradoxical aspect of the Algol binary system lies in its unexpected drop in brightness during eclipses, which was later explained by the presence of a third star influencing its behavior.