The Geminids are one of the big deal meteor showers that happen every year. In fact, they're regarded as one of the most reliable and impressive. They're also a little strange.
Most meteor showers happen when Earth and a comet cross paths, slingling rocks, dust, and debris from the comet's tail into our atmosphere. The sudden influx of shooting starts that results is a highly noticeable event and humans have been recording them for millennia.
The Geminids are different. They sort of just appeared, seemingly out of nowhere, back in 1862. And it wasn't until the 1980s that scientists were finally able to identify the thing that was producing them. At which point, ish got weirder.
That's because the object, known as 3200 Phaethon, is really confusing. It doesn't seem to be a comet. At least, not a normal, healthy, functioning comet. It doesn't even have a tail. In fact, at this point most scientists think it's probably an asteroid, which then leads to still-yet-unexplained question of where all the meteors come from. Asteroids, after all, do not typically accumulate tails of small rocks. So far, the best guess has to do with 3200 Phaethon's orbit, which over the course of about a year and a half takes it closer to the Sun than Mercury and then back out further from the Sun than Mars. Those wild temperature swings might lead to the asteroid cracking and throwing off dust and debris, which then becomes meteors. But, as a NASA info page pointed out in 2010, that explanation doesn't totally cut it. Read the rest