It's time to stop thinking of comets as dirty snowballs
Scientists had expected to see a dirty snowball
coated with thick layers of dark dust which would obscure any interesting features.
And then we add dry ice and make a frozen, dirty snowball
That's the equivalent of a dirty snowball
the mass of Mars.
The comet--and perhaps many others--may resemble an icy dirt ball more than it does a dirty snowball
, says Lisse.
But, Ganymede looks like a dirty snowball
next to Jupiter, the largest planet in our solar system.
Whipple, in search of a new paradigm to better explain cometary phenomena, suggested that their nuclei are frozen water, ammonia, methane, carbon monoxide, and carbon dioxide combined with fine-grained meteoritic materials that come together at extremely low temperatures to form a big dirty snowball
Eight years after Comet Hale-Bopp passed through the inner solar system, the dirty snowball
is still active despite being a whopping 21 astronomical units from the Sun.
Now Deep Impact scientists hope to send the comet watcher to a second dirty snowball
In 1951, he suggested that comets contain large amounts of ice interspersed with dust--a theory that became known as the dirty snowball
Clean snowballs (as opposed to dirty snowballs
, or "comets") of more than five or six words in length seem to be difficult to construct, which is why I am impressed with this rather immaculate eight-word snowball contributed by Jeff Grant to a recent Kickshaws: