Expert: Courtney Seligman - 12/17/2010

Question
QUESTION: In the old 60s TV show "Lost in Space" the Robinsons landed on a planet with some pretty extreme seasons. For the first few weeks on the planet, conditions remained relatively temperate, ranging between the 30s and 70s (Fahrenheit). Eventually the temperature begins dropping below zero at night.

Then in only about a couple of days the temperature rapidly drops to 150 degrees below zero. The Robinsons head south, hoping to find warmer climates there. In a matter of days the temperature returns to normal at the Jupiter 2, and the Robinsons barely managed to avoid being burned alive from being too far south.

After this brief period of extreme temperature change, the climate returns to normal. I'm guessing these extreme temperatures only occur roughly once a year (which is probably similar to an Earth year). John Robinson claims that the planet's extreme temperatures are the result of a highly eccentric orbit the planet's sun. But if this were true, wouldn't it be extremely cold or extremely hot most of the year? Why would it be relatively temperate for most of the year?

Now, Irwin Allen is known to have had little interest in maintaining scientific accuracy in the show. But I'm wondering, is there a hypothetical set of circumstances where this type of seasonal activity could occur?

I'll re-iterate the circumstances so as to be as clear as possible. The Jupiter 2 crash-lands on an Earth-like planet in a fairly desert-looking location. Temperatures range roughly between the 30s and 70s (Fahrenheit). After a few weeks, their meteorological instruments predict that the temperature will drop to 150 degrees below zero by the day after tomorrow. So the next day they head south in the Chariot (their all-terrain vehicle) fast, except for Dr. Smith, who chooses to stay behind.

As predicted, the temperature outside the Jupiter 2 continues to drop. During the night (I think that this is the second night after the day on which it was predicted that the temperature would hit 150 below), the temperature reaches 104 below, and seems to stay there for around an hour. Then the temperature begins to rise, quite rapidly.

The extreme temperature changes seem to cause periodic seismic events over the few days that the changes occur.

Meanwhile, further south, the Robinsons are crossing an inland sea that's covered in solid ice. Partway across the sea, the Robinsons realize that the temperature has risen to a little above zero (30 degree difference in the last hour, which I'm guessing roughly correlates with the rate of increase in temperature observed back at the Jupiter 2).

By the following night, the Robinsons are 70 or 80 miles south from the Jupiter 2 (seems like they'd be further by then, but I guess the Chariot doesn't go very fast). They've made camp, and it's practically too warm for a fire. John Robinson and Major West find plant-life that's been burned and then frozen very soon after.

In the morning, they remain in the same location. John Robinson realizes that the planet's orbit is a flat ellipse, and predicts that it will become incredibly hot (but exactly how hot, he can't be completely sure). They immediately begin making preparations to survive this extreme heat.

The Robinsons construct a solar shield. The rapid thawing causes another small quake to occur. As the hottest part of the day approaches, they hide under the solar shield and then cover themselves with solar blankets. The plants around them burst into flame as the landscape is roasted by the heat of the day. Further north, closer to the Jupiter 2, the temperatures become relatively tropical.

After the brief ordeal is over, the Robinsons turn around and head back north, towards the Jupiter 2. The Chariot is amphibious and has no trouble crossing the now melted inland sea, at first. But during the crossing (at night I believe) a major storm hits, adding significant peril to the journey.

After surviving the inland sea, the Robinsons reach land and find a tropical paradise. Evidently the plant-life grows extremely fast on this planet, presumably having adapted to the extreme temperature differences. Apparently they must still cross miles of barren terrain past jungles before reaching the Jupiter 2.

And as previously stated, at the Jupiter 2 it remains relatively temperate (30s to 70s, or perhaps a bit higher). And, apparently, only once every solar year does the temperature drop to around 104 below.

So I ask, out of curiosity. Is there any way a planet like this could possibly exist? Is there a hypothetical set of circumstances that could make this possible? Or at least plausible?

ANSWER: No, there's no way that orbital effects could cause such changes. You could have very high temperatures at one end of the orbit and very low ones at the other end if the orbit were very elongated (eccentric). But the orbital speed would be very high at the near (hot) end and very low at the far (cold) end of the orbit, so there would be a very short time with high temperatures, a longer time with gradually increasing or decreasing temperatures, and a very long time with very low temperatures.

If it is presumed they landed when the planet was heading outward, and at a distance that provided temperate weather, the temperature would gradually drop (from day to day if the orbital period were short, or from week to week if the period were long). But the change in temperature would be more and more gradual the further out (and the slower) they went. So if they had "moderate" temperatures for even a week or two, freezing temperatures would last for months, not nights.

As they swung back toward the star, and the long period of very low temperatures ended, there would be a period of moderate temperatures comparable in length to the time such temperatures lasted after they arrived. So the temperature couldn't suddenly swing from very cold to very hot.

At the "near" end of the orbit to the star, the motion could be very fast, and very high temperatures might not last very long; but the rest of the scenario makes no sense (nor, for that matter, does the idea of any kind of life surviving such conditions).

Of course, if they could survive in space between landings, the ship's temperature controls should have kept them nice and comfy no matter what conditions were like outside. So all they had to do is stay in the ship, and let the weather outside do what it wanted without them. But I presume the ship's temperature controls were conveniently on the fritz.

---------- FOLLOW-UP ----------

QUESTION: So (if I'm not mistaken), on Earth, the seasons are not so much caused by the Earth's position in orbit, but more by the tilting of the Earth on it axis, right?

So, hypothetically, could these conditions possible occur if the planet had a relatively normal orbit and happened to swing very close to another planet during its orbit, causing the planet the Robinsons are on to tilt?

Answer
That's correct. Our distance from the Sun is relatively constant (varying by only 3.4%), and the effect of the change in distance is insignificant in comparison to the effect of our tilt, as you can tell from the fact that we are closest to the Sun in early January, and 3 million miles further away in early July. The seasonal effects due to our tilt are about 20 times larger (at mid-latitudes) than the orbital effects, so we don't even notice those. Even the fact that the southern hemisphere has more oceans than the northern hemisphere is twice as important as the change in distance from the Sun.

Moving close to another planet wouldn't be likely to cause the tilt to change. The effects of other planets, even if relatively close, are primarily confined to changing the orbit. To change the axis of rotation the planets would have to get so close that they were practically torn to pieces by tidal forces -- in which case, the change in climate wouldn't be noticed, because the Robinsons would be dead long before any changes could occur. Note: The 1954 film "When Worlds Collide" featured a near passage of another planet, which caused widespread havoc (although not nearly as much as would have happened in real life); but was close to reality in not attributing any changes in climate to the passage.