In the case of Comet 67P Churyumov–Gerasimenko, the way that the surface acts as it heats up on approach to perihelion is looking remarkably like the movie Armageddon. You'll recall that Armageddon was about a planet-busting, civilization-ending comet headed directly toward Earth. To rescue our planet and its denizens, NASA enjoined a crew of oil well disaster fixers led by Bruce Willis to go up and drill a hole into which a nuclear device could be placed. Detonating the device would turn the deadly comet into a great source of meteor showers for centuries to come.
Though Armageddon was far from scientifically accurate, two aspects of what was happening on the surface of the warming nucleus are turning out to be very similar to what Rosetta is seeing on 67P.
Those two things are the apparent formation of big sinkholes as the comet stuff blasts into space:
Comet sinkholes generate jets
The sinkholes endangered the crews in Armageddon and swallowed up at least one of their platforms, as I recall.
The second thing are the powerful jets themselves. 67P proved it could fire off a massive jet just a couple of days ago.
Comet's firework display ahead of perihelion
The jet it blasted into space was so strong that it disrupted the flow of the solar wind around the comet, and could be viewed by the Rosetta cameras without increasing the gain setting to make it brighter.
|The strong jet is in the middle frame of the sequence.|
In the movie, being on top of a jet when it blew was a fatal mistake to other members of the oil rig astronaut world savior crew.