The Goldilocks Planet
“The “habitable zone” is the region around a star where a suitable planet could sustain the conditions necessary for life. Most astronomers take it to be the region where the balance between stellar radiation onto the planet and radiative cooling from the planet allows water on the surface to be a liquid; this definition also presumes the planet has an atmosphere and a solid surface. In our solar system, the Earth is cozily situated in the middle of the habitable zone which, depending on the model, extends roughly from Venus to Mars.
The Kepler satellite, as previously reported here (22 July 2011), has recently announced the detection of 1235 planetary candidates around other stars. How many of these exoplanets lie in their habitable zones and might (at least to this extent) be suitable hosts for life? The original Kepler paper concluded that fifty-four were in their habitable zones.
CfA astronomers Lisa Kaltenegger (now at the Max Planck Institute for Astronomy) and Dimitar Sasselov have explored in more detail the conditions necessary for a planet to lie in its habitable zone. They take into account more carefully five factors: the incident stellar flux and its spectral character, the planet’s eccentricity (how its distance from the star differs during its orbit), the planet’s reflectivity including the effects of partial cloud cover, the greenhouse gas concentration, and finally, some details of the planet’s atmosphere.
With some reasonable assumptions the scientists find that, in the case of the solar system, the habitable zone extends from the orbit of Venus to well beyond the orbit of Mars (nearly to the inner edge of the main asteroid belt). When they apply their models to the 1235 candidates in the current Kepler catalog they find that the original estimate of fifty-four planets was far too high. A more accurate estimate finds that only six of the Kepler exoplanetary candidates could be in a habitable zone, assuming that they have atmospheres. The results are another important step in refining the search for Earth-like planets (not just Earth-sized planets) around other stars.
Battleship – The Goldilocks Planet
The term Goldilocks planet was not invented for this film, of course, it refers to any planet of specific properties which would allow for life as we know it to exists, one which avoids the extremes that would be difficult to survive within. Such a planet for example, will have some regions of surface temperature between 0 and 100 degrees Celsius – to allow for liquid water on the surface – and the atmospheric pressures required to let it flow around on the surface without floating away.
Enter Peter Berg (Hancock) produces and directs the upcoming blockbuster, “Battleship,” an epic adventure film that unfolds across the sea, the sky, and on land, as planet Earth fights for its survival against a superior alien force. AND, they were invited!
There are other factors of course, and it makes sense to a certain extent that malevolent alien lifeforms would look for a planet like that to conquer for themselves. The odd part here is that the characters in the film seem to be talking about such planets as if they are so rare that they have only just discovered the first one, when in fact real scientists have already confirmed over a dozen such planets in our part of the galaxy, with several dozen more candidates which require further study, and believe that hundreds of such planets are likely to exists across the Milky Way alone.
Further, the characters seem to be sending a weirdly visible message out to that planet, which apparently responds with ships almost immediately. However, with any communication technology even dreamed of, any broadcast would take years to get to such a planet. The nearest star system to ours (which doesn’t have a Goldilocks planet) would take over 5 years just for our signal to reach it, and no amount of alien technology could help them receive it any faster. This setting doesn’t look very futuristic either, so I’m not guessing that they will try to explain it away by talking about some futuristic We only know so little about the film so far, and we can already see that it’s not going to have any strong sci-fi elements.
Essentially, this will be an effects only type of film. Those effects look pretty so far, but if you leave your brain turned on in the theater, you won’t be able to enjoy them. Of course, it’s still more than I ever expected from a film based on a plotless semi-tactical boardgame.
The idea of the boardgame, if you somehow haven’t played before, is that each player fires missiles blindly at the opponent’s ocean, only knowing if their missile hits, then basing further moves on the pattern of hits and misses, taking turns until one fleet or the other is completely covered in little red ‘hit’ markers. Mostly it’s a game of chance, with little actual skill unless you get two players who know the game or each other very well.
In this film, the blind firing is represented by a lack of ability to ‘see’ the alien ships on sonar or radar, and the limited engagement space is created by a force-field the aliens deploy.
The ships, guided by a surly Liam Neeson and a rebellious Taylor Kitsch, will have to find a way to fend off the aliens blindly from inside their limited field of engagement. The sub-plot puts Kitsch’s character in bed with Neeson’s character’s daughter, played by Brooklyn Decker.
Battleship, which also stars Alexander Skarsgard, Rihanna, Josh Pence, Jesse Plemons and Peter MacNicol, opens May 18, 2012.