First of all, lets look at what Hubble saw. All data from the space based telescope is logged and recorded, including data from its on-board star tracking system, which is essentially software that keeps it oriented by looking at known stars and locking the position of the telescope using orientation software. When astronomers recently went back through data from the the last 4.5 years from the tracker, they found a blip that looked very much like an object had passed in front of the star it was looking at. After further analysis, they found it was a Kuiper Belt object. The Kuiper belt - as Phil puts it, is the torus of icy comet nuclei orbiting the Sun out past Neptune.
Visualization of Hubble seeing the object
Wow! The cool thing is that the object turns out to be a little over a kilometer in size, making it by far the smallest Kuiper Belt object ever observed.
Second, let's take a look at the iceberg, which is currently breaking up and melting in the Indian ocean.
The drifting iceberg from space
Note the scale at the bottom left of the image - that thing is 25 kilometers in size!
So, the cool thing is that the object recently discovered by Hubble is much smaller than the iceberg, and since the object is about 4.6 billion miles away, I think that is one achievement that Hubble can be very proud of.
Happy Freezing, Spacers!
Images credit: NASA, ESA, and G. Bacon (STScI) and NASA Earth Observatory