Algol, a variable star in the constellation Perseus. (A variable star is one that changes in brightness.) Algol, which was observed by the ancient Greeks and named by the Arabs, is now known to be a complex system of at least four stars revolving around one another. A pair of the stars forms an eclipsing binarytwo stars that pass in front of each other in turn, causing a periodic (cyclical) dimming of their combined light. Algol dims regularly every 21 days and 21 hours.
The occasional sunspot can interrupt communications here on Earth. But major solar flares have the potential to cause more havoc. Could a flare-up wipe out all our electronics?
Venus is the second planet from the sun, and is about the same size as Earth. It is a terrestrial planet, meaning it has a solid surface. But the harsh conditions on Venus make it very inhospitable. Two spacecraft, Pioneer Venus 1 and Magellan, were able to penetrate the thick atmosphere of this planet.