Institutions around the world are hosting events to raise awareness about asteroids. You can find events near you on the Asteroid Day events page or watch live discussions and other asteroid-related programming from the comfort of your home during a 48-hour webcast. Tune in to the Asteroid Day broadcast live here on Space.com or on the Asteroid Day homepage.
While we probably don't need to worry about another huge asteroid like the one that killed the dinosaurs crashing into Earth in the foreseeable future, asteroids still pose a threat, NASA and other space agencies have said. [Gallery: Potentially Dangerous Asteroids]
A much smaller asteroid that exploded over Chelyabinsk, Russia, in 2013 injured more than 1,200 people, and shock waves damaged buildings up to 58 miles (93 kilometers) away from the explosion. In April, an asteroid twice that size — and about as big as the Tunguska asteroid responsible for the worst impact in recorded history — made an unusually close flyby of Earth.
NASA estimates that there are around 10 million near-Earth objects (NEOs) the size of the space rock that hit Chelyabinsk, but those small NEOs are more difficult to detect before they enter Earth's atmosphere, NASA officials said during a news conference on the White House's "National Near-Earth Object Preparedness Strategy and Action Plan," which was released June 20.
Fortunately, NASA also estimates that it has found more than 95 percent of all asteroids big enough to cause a global catastrophe, and none of them pose a threat. However, astronomers believe they have found only one-third of all space rocks in Earth's vicinity that measure at least 460 feet (140 meters) wide, which is big enough to destroy an entire state, NASA officials said.
"Asteroid Day events will address science as well as government and private-sector initiatives to study asteroids, and particularly advanced efforts to develop greater detection, tracking and deflection techniques," Asteroid Day organizers said in a statement.
To kick off the annual Asteroid Day activities, British physicist and BBC commentator Brian Cox hosted a preview program Friday morning (June 29) with celebrities like Bill Nye ("the Science Guy"), retired Canadian astronaut Chris Hadfield, Apollo 9 astronaut Rusty Schweickart and evolutionary biologist Richard Dawkins.
The European Space Agency (ESA) also joined the conversation Friday with a 90-minute "infotainment" event at the Technical University Darmstadt in Germany.
One portion of the event was a discussion of the flaws in the 1998 film "Armageddon," in which a ragtag team of oil drillers voyage to a Texas-size asteroid that's screaming toward Earth. They bore a deep hole into the space rock and then plant a nuclear bomb into it, breaking the asteroid apart and saving civilization.
As you can probably gather from that brief description, there are a lot of flaws in "Armageddon." For starters, there's the absurdity of sending people out to do this dangerous deep-space work. And, as has been noted by numerous folks, no nuke ever invented is anywhere close to powerful enough to destroy a space rock the size of Texas.
ESA flight dynamics engineer Rainer Kresken brought up several other issues during Friday's event in Germany. For example, in real life, the heroic oil drillers wouldn't be able to get anywhere close to that giant asteroid, which would be accelerated to tremendous speeds by our planet's gravity.
"If such an object, whatever kind it is, approaches Earth closer [than] the moon, it's way faster than you can approach it with a space shuttle or any existing" vehicle, Kresken said.
If you stay up extra late (or wake up early, depending on where you are), you can catch a special showing of the science-fiction film "51 Degrees North" on the Asteroid Day live stream at 2:10 a.m. EDT (0610 GMT). In the movie, a group of asteroids is heading straight for Earth, and the world has only three weeks to prepare.
And if the movie leaves you feeling anxious about Earth's impending doom, the next program — a 50-minute Discovery Channel special titled "How to Survive an Asteroid Strike" — may help calm your nerves.
The rest of the day's programming includes live events with scientists at NASA, the European Space Agency, the European Southern Observatory and more. You can find the full broadcast schedule here.