There's a meme going around the internets and in the MSM that Earth is not alone in global warming: other planets, according to this story, are experiencing it too.

The usual crowd, along with many others, are taking this idea and running with it, saying that if other planets are warming up, obviously the warming on Earth is not man-made. But there's a small problem with this: it's wrong (for a more detailed analysis of this, see my blog post at Bad Astronomy).

The idea is that evidence shows that Mars, Jupiter, Neptune's moon Triton, and even tiny, distant Pluto are warming up. The only thing these objects have in common is the Sun-- so therefore the Sun must be the culprit, and we -- the polluting, self-absorbed humans -- are off the hook.

However, as an astronomer and a skeptic, I did something most ditto-heads don't do: I actually did some research. What I found is that first of all, the evidence that Mars is warming up is tentative; basically, the southern ice cap appears to be shrinking, and along with other evidence this indicates that there is some sort of climate change going on. However, the change may very well be local, confined to the southern region. Plus, we already know that other factors, like the shape of the orbit of Mars, contribute to climate change there. Looking to the Sun as the source of this is unwarranted.

The claim about Jupiter warming is simply wrong. There are localized places where gas from deep in the atmosphere (where it's warmer) is bubbling up, but this is again a localized effect, and not an indication of global change. Jupiter's atmosphere is a very weird, turbulent place, and honestly we don't understand it all that well. Calling this jovian global warming is premature at best.

Triton is entering its summer season, and due to the peculiar orbit it has, this summer will be a particularly extreme one. If it's warming there, it's a seasonal change, and expected.

And as for far, wee Pluto, it's so far out that if any warming there were from the Sun warming up, the Earth, which is much closer to the Sun, would be roasted. Since the effects of GW here on Earth are subtle, it's safe to ignore Pluto.

My blog post about this on my site has generated a lot of ire, of course. No one likes having huge, gaping holes pointed out in their claims! But science and skepticism aren't about denying, they're about being rational. And that means looking at evidence, weighing it fairly, applying critical thinking, and then discussing it clearly.