Comets have always captivated people.
Some cultures saw the appearance of comets as omens, and some have hypothesized that a comet served as the Star of Bethlehem from the Nativity story.
The word comet originally meant "long-haired star."
The "long hair" refers to their tails, but these objects are much closer than the stars outside the solar system.
Like the planets, comets orbit the sun.
The planets have nearly circular orbits in roughly the same plane, so they appear in the Zodiac constellations in our sky.
By comparison, comets have extremely elongated orbits ranging in distance from far beyond Neptune's orbit to grazing the sun.
These orbits are also tilted in any possible direction, so comets can be found anywhere in the sky.
Comets heat up as they approach the sun, causing icy materials to boil away from the surface.
These gases erupt as jets and eject dust and rock as well.
Sunlight and solar wind pushes all of this away from the weak gravity of the comet to form tails consisting of the type of material being ejected.
These tails can stretch for millions of miles, reflect sunlight and be potentially visible without a telescope.
In 1705, Edmond Halley used Newton's recently published laws of motion and gravity to calculate that a comet observed in 1682 was seen multiple times over centuries and would return in 1758.
Halley's comet was found again in 1758, confirming it as the first non-planet known to orbit the sun. Halley's comet has historical records of its appearances over 2000 years, and it's expected to return in 2061.
Each time a comet approaches the sun, solar radiation makes the rocky-icy nucleus more fragile.
Astronomers don't know how many more times Halley's comet will appear in the sky until it breaks apart.
Comets are named after their discoverer(s), either a person or a robotic telescope.
Recently, a comet discovered in 2023 called Tsuchinshan-ATLAS grew much brighter as it got closer to the sun.
Observers around the world were able to see it even before twilight left the evening sky in light polluted locations.
It was the brightest comet seen since McNaught in 2007 and Hale-Bopp in 1997.
Nobody knows when the next bright comet will appear.
The brightest comets often have orbits lasting thousands of years, and they are making their first appearance in recorded history.
Some originate from the Kuiper belt, and others come from a hypothetical region called the Oort cloud.
If astronomers notice a comet get much brighter, they help spread the word to news organizations and the public to experience it for themselves.
Keep an eye out for the next rare opportunity!
Upcoming events The Staerkel Planetarium's full schedule of public programs and online ticket sales is available at parkland.edu/planetarium. Contact the staff at [email protected] for more information or to book a private show. The Champaign County Museums Network has information at champaigncountymuseums.org.
Laser shows:Dec. 5-8.'Season of Light' and 'Santa's Secret Star':November and December.Sensory-friendly programs:Dec. 14.