Almost all scientists around the world who study the Chicxulub impact agree that a six-mile wide asteroid that came from outer space smashed into the Earth 66 million years ago to create the Chicxulub Crater. There are other names you can call that thing besides just "asteroid," though.
Asteroids are objects that look like this:
Even though that GIF kind of looks like a potato in zero gravity, asteroids are actually rocky objects in space that tend to be irregular in shape. They range from boulder-sized to the size of a dwarf planet, like Ceres here, which is big enough to be round, but not big enough to be a planet:
So, asteroids are big. If the rocky objects in space are smaller than a meter in width, then they are called meteoroids.
Asteroids that collide with the Earth also get called Near-Earth objects , because, as you probably already guessed, they are asteroids near Earth. Near-Earth asteroids often come originally from the asteroid belt, which is found between the orbits of Mars and Jupiter. The asteroid belt is a whole bunch of asteroids that basically follow the same path in orbit around the Sun. The asteroid belt is not a belt like the belt I am wearing right now, because the asteroids in the asteroid belt are not all connected together to form one single object (also I couldn’t put the asteroid belt on and expect it to hold up my pants). The asteroid belt is more like a continuous parade of separate, drifting asteroids, except in this parade none of the asteroids are in a marching band and none of them are on a float chucking Jolly Ranchers at small children. Also, you would usually have to wait a long, long time from when you saw one asteroid go by until you see another one.
Asteroids sometimes get knocked out of the asteroid belt because of changes in gravity around them, usually caused by the giant planet Jupiter. Those wayward asteroids sometimes head in our direction to become Near-Earth objects.
If geologists ruled the world, then I could also call the thing that created the Chicxulub Crater a bolide. That is what geologists call any astronomical object that impacts the Earth. Unfortunately, geologists don’t rule the world. They don’t even rule all of science, because if you asked an astronomer what a “bolide” is, they would say it is an astronomical object that burns up in the atmosphere without striking the Earth, like this one that flew over Russia in 2013:
So since “bolide” can mean two different, contradictory things in the world of science, I haven’t used that term. (Also, the title of the video is inaccurate since the astronomical object in the video didn't actually crash into Russia. It burned up over Russia. Way to go, YouTube posting person. [PS. These snide remarks will all make sense after you read the next paragraph])
“Meteor” and “meteorite” are also contenders, but meteors burn up in the atmosphere before they touch the ground, so it's not accurate. “Meteorite” does work, because it refers to both meteoroids and asteroids that impact the ground, but it is used more commonly with much smaller impacts than Chicxulub.
So what do you call that thing that created the Chicxulub impact? You have many options to choose from. Or you could just make something up, like calling it "Tim."
If you want to learn something else about the Chicxulub impact asteroid, read my book Uncovering Earth’s Secrets.
Online References and Resources:
Cornell University. "Asteroid Belt."
National Geographic. "Asteroids and Comets."
Photos and Images:
Click the photos, images and GIFs used above to find their sources.