This at least accounts for the fact that a particular group of meteoroids shares with its parent comet more or less the same orbit , which can remain relatively unchanged over eons . an immediate consequence is that our earth makes periodic rendezvous with this meteoroid swarm , thereby culminating in a regular display of these celestial fireworks . to name a few , we have the lyrids in april and the geminids in december 流星雨的成因是地球遇上了一群密集的流星体，一般相信，流星群是由周期性彗星分解出来的物质或由瓦解了的彗核所形成，所以流星群和其母体彗星有大致相同的轨道，由于流星群的轨道颇为固定，所以地球会周期性地穿越这些流星群，形成固定出现的流星雨，例如四月天琴座流星雨十二月双子座流星雨等。
