Fun Astronomy

One of my favorite classes ever has been the Astonomy class I took this semester.  I have learned so much about the Solar System and Earth.  I'll have to make some posts about the interesting things I learned in class.

Yesterday, we talked about comets, which are really just "dirty snowballs" in space.  They typically orbit out beyond Pluto but sometimes come into the inner Solar System.  In fact, one of them collided with Jupiter several years ago in a pretty spectacular way.  As it entered Jupiter's atmosphere it broke up into 21 pieces that impacted with Jupiter, creating a hole the size of the Pacific Ocean. 

The pieces of the comet entering Jupiter's atmosphere

I was a bit surprised to learn that there are an estimated 10,000 comets near Earth.  Most pass by us but are nowhere near close enough to even be seen in the sky without a telescope.  Whew!  Some come closer, like Halley's Comet, but still are not close enough to impact us.  Whew, again!

I found out that comets leave dust and debris in the wake of their orbit.  When they come close to Earth, that debris gets trapped within our orbit.  Every year when Earth reaches that point in its orbit, we fly through that debris, creating meteor showers. 

As I said earlier, comets are really just dirty snowballs flying through space.  Much of the ice is not water ice, but rather gases that have frozen.  As the ice melts, the comet vents those gases.

In class yesterday we had the opportunity to make our own comets.  We used water ice (ice cubes), dirt, carbon, ammonia, water (for "glue"), and dry ice (to represent the gases).  We just mixed it in a bowl covered with a garbage bag.

Our comet venting gases

Another view

We lifted it up and realized we didn't mix the dirt in very well.

As it melted it sounded like Rice Crispies -

snap, crackle, pop

My girls think it would be fun to make their own comet.  They have also learned quite a bit this semester!