On May 19, 1910, Earth had its closest encounter with Halley’s Comet. Most comets, sometimes called “dirty snowballs” or “icy dirtballs”, usually follow an orbit that keeps them far away from the sun. Those comets are invisible from Earth, even with the best telescopes. However, if a comet gets closer to the sun, heat from the sun may begin to evaporate some of its ice, which releases the comet’s dust and rocks. This material is the “tail” of a comet seen from Earth.It takes about 76 years for Halley’s Comet to make one orbit around the sun, and astronomers have been able to predict its return since the 1700s. Centuries earlier, ancient astronomers from China to Babylonia had accurately, consistently reported seeing the comet, but failed to recognize it as a single object or recurring event.
Term Part of Speech Definition Encyclopedic Entry accurately Adverb
exactly or perfectly.
person who studies space and the universe beyond Earth's atmosphere.
celestial object of matter surrounded by ice and dust that orbits the sun and leaves a tail of debris.
maintaining a steady, reliable quality.
to meet, especially unexpectedly.
to change from a liquid to a gas or vapor.
path of one object around a more massive object.
to know the outcome of a situation in advance.
to identify or acknowledge.
star at the center of our solar system.
stream of gas or dust debris behind a comet.
scientific instrument that uses mirrors to view distant objects.