How do comets get their tails?
- Most comets stay frozen in the outer solar system. Only a few enter the inner solar system where they can grow tails.
- When a comet nears the sun, its ices can sublimate into gas and carry off dust creating a coma and long tails (plasma and dust tails)
- A comet ejects small particles that follow it around in its orbit and cause meteor showers when earth crosses the comet’s orbit.
Where do comets come from?
- The comets we occasionally see in the inner solar system come from two major “reservoirs” of comets; the Kuiper belt or the Oort cloud
- Kuiper belt comets orbit in the region in which they were formed, just beyond Neptune’s orbit. The more distant Oort cloud contains comets that once orbited around the Jovian planets.
Why is Pluto not considered a planet anymore?
- Its 248 year orbit is elliptical and inclined than that of the first 8 planets.
- It proved to be a mis-fit among planets because of its size and composition; its far more smaller than the other planets and its rich-ice composition fits neither the terrestrial or Jovian characteristics.
How big can a comet be?
- In the Kuiper belt, icy objects were able to grow to hundreds or thousands of kilometers in size. The recent discovery of Eris is the largest of these object in the belt with Pluto the second largest.