Meteors

So far in this module, following the briefest of explanations about how our Solar System formed and evolved (which was needed for explanation of what asteroids and comets actually are), you went on to explore what we know about asteroids and comets, and the space missions we’ve sent out to study them. But apart from one brief mention in the video you watched on the OSIRIS-REx acronym, your investigation so far has omitted the most important source of information we have about asteroids: all the freebies that fall to Earth.

Learning Activity

Watch the video and find answers to these seven questions:

  • What is the difference between a meteoroid, a meteor, and a meteorite?
  • What is the source of energy that causes light to be emitted when a meteoroid hits our atmosphere, and what causes the meteoroid to heat up?
  • What is the difference between sporadic meteors and those you might observe in meteor showers?
  • How are meteor showers named, why are they so predictable, and why is it best to view one after local midnight?
  • What is a fireball?
  • What are the three categories of meteorites, the two subclasses of stony meteorites, and where do the differences come from? (at this point in the video, you should recall what was said in the OSIRIS-REx video about comparing the sample from Bennu to its spectrum and to meteorite samples).
  • Is there any current danger from meteoroids, and what are astronomers doing to resolve that?

Update: Since this video was made, several large meteoroid entries — such as the 2013 Chelyabinsk event (video below) and the 2023 Winchcombe carbonaceous meteorite fall — have provided valuable high-speed footage and laboratory samples that confirm Phil’s explanations about atmospheric heating and fragmentation. Networks of all-sky cameras and radar now routinely track incoming meteors, linking recovered meteorites to specific parent asteroids.

Next, you’ll turn your attention back to the bigger picture—how all of this debris, dust, and rock fits into the story of how our Solar System formed in the first place.