It’s time for another giveaway! Yeah, I know, the last one just ended, but I’m moving soon, so I need to get rid of stuff.

The rules are exactly the same as last time, except I’ll ship anywhere this time. And I could go into a lengthy description of the DVDs, but let me let this guy explain it all:

The two DVDs are The Dish, and Hyperspace. They are used, but work. They are Region 1 DVDs, by the way. Since they are both used, their combined value is unlisted, so I’ll say it’s <Dr. Evil voice>one meellion dollars <\Dr. Evil voice>.

As usual, I have opened a thread in the Fun and Games section of the BAUT forum. Just post there — once only — and you’re entered. I’ll end the contest at noon Pacific time on Saturday, May 5. I’ll then pick a random number and whoever has that post number wins! I’ll contact you via private message through the board as well as email. If I don’t hear back by noon Tuesday I’ll pick another winner. As for the other rules, check the old contests.

I’ve dropped Chris Pirillo’s name here on the blog a few times. He was the host of a show on TechTV years ago, and I went on a few times to make fun of bad SF movies. He and I became friends, though he is so busy reinventing the Internets that I hardly get a chance to talk to him.

That’s why I dropped everything and drove downtown to San Francisco a couple of Friday nights ago — he was here to attend some meetings, and had the evening free. It was cool to see him again and hang out. We talked web, we talked web 2.0, we talked about his live streaming adventures.

We also ate ice cream. We went to a place that sold lots of Indian flavors (<Apu>You can really taste the chutney!</Apu>) but also had some stuff I was used to (I got the mint chocolate chip). Chris is more adventurous, and got the sesame seed ice cream, which he claimed tasted like peanut butter. That sounds good, and he offered me a taste, but 1) I didn’t think it would taste good after mint, and 2) the color of his ice cream was… a little off-putting:

As nice as the flavor may have sounded, I can’t bring myself to eat slate-blue-grey ice cream. But Chris is an early adopter, and I’m more of a follower. When all the tragically hip latte-sipping technorati start eating it, then I probably will too.

There is some news making the rounds that Earth is not the only planet experiencing global warming. Mars, for example, possibly appears to be getting a bit warmer, as are Jupiter, Neptune’s moon Triton, and even Pluto.

Could this mean that global warming is caused by the Sun and not man’s pollution?

I am certainly seeing global warming deniers and others taking this information and running with it (like here, for example, or here, and on Benny Peiser’s CCNet on March 7, 2007, though I don’t have a link for that). However, let’s take a skeptical approach shall we?

First off, I want to make a very big point here: the changes in the Earth due to global warming, while real, are somewhat subtle. Yet the Earth gets most of its heat from the Sun, so if the Sun were the cause, we’d expect the effects of warming to be much stronger on Earth than any outer planets. So any really strong signal of global warming on outer planets like Jupiter or especially Pluto, if real, are very unlikely to be due to the Sun.

Second, what I am seeing in these arguments is a very dangerous practice called "cherry picking"; selectively picking out data that support your argument and ignoring contrary evidence. It certainly looks interesting that Earth, Mars, Jupiter, Triton, and Pluto are warming, and if that’s all you heard then it seems logical to think maybe the Sun is the cause. But they aren’t the only objects in the solar system. What about Mercury, Venus, Saturn, Uranus… and if you include Triton to support your case, you’d better also take a good look at the nearly 100 other sizable moons in the solar system. Are they warming too?

I have heard nothing about them in these arguments, and I suspect it’s because there’s not much to say. If they are not warming, then deniers won’t mention them, and scientists won’t report it because there is nothing to report ("News flash: Phobos still the same temperature!" is unlikely to get into Planetary Science journals). However, I can’t say that with conviction, because the absence of evidence is not evidence of absence. Any planetary scientists reading this blog entry, please contact me. I’m interested in hearing more.

Third, if you actually read the articles about the specific cases of planetary warming to which I linked above, you see that they all have separate explanations:

• First off, is Mars even warming globally at all? Perhaps not — it might be a local effect. And if it is global, there already is an idea of why that might be happening: it would be due to periodic changes in its orbit, called Milankovitch cycles. The Earth has them too, and they do affect our climate. And the guy who is proposing that the Sun is warming Mars doesn’t think CO₂ is a greenhouse gas. I think his science is a little suspect. His reasoning is certainly specious– he says if Mars and Earth are both warming, it must be due to the Sun. As I point out above, that is clearly not necessarily the case. Even if this martian warming turns out to be true, it may just be a natural effect of the shape of the orbit of Mars.
• The evidence for Jupiter’s global warming is nothing of the sort. It is evidence that there are warm spots, with storms rising to the tops of the clouds. This may just be a local effect, and not global. Jupiter’s atmosphere is fiendishly complex, and not well understood. If you’ve ever looked at the planet through a telescope, you can clearly see thick horizontal bands across the disk; these are enormous wind patterns that dwarf the Earth. A few years ago, one of the dark bands disappeared completely. For reasons unknown to this day, it sank a bit in the atmosphere, and opaque clouds covered it up. I saw it many times through my ’scope, and it was bizarre. Then, after a while, it reappeared, just like that. My point: any claims about Jupiter’s atmosphere when it comes to global warming must be approached very carefully. We don’t understand the dynamics of that system.
  
  

  Hubble image of Jupiter showing banding.

  Also, Jupiter’s atmospheric physics is dominated by the internal heat of the planet, and not by the heat from the Sun. So even if the Sun did heat up somehow, the effect on Jupiter would probably be a lot less dramatic than here on Earth.

• With Triton, Neptune’s moon, it says in the very article quoted that Triton is approaching an extreme summer season, due to the tilt of its orbit. This happens every few centuries. So the Sun can be constantly chugging away, and Triton would warm up anyhow. Mind you, Neptune’s orbit is 165 years long, so we haven’t even observed it for a full orbit since the invention of modern detectors capable of giving us good data. Therefore it’s very difficult, if not impossible, to distinguish between factors like the Sun warming up Triton anomalously, or just the usual changes in the moon due to seasons.
• As for tiny Pluto, its dynamics are very poorly understood. What we do see is that its atmosphere appears to be thicker than expected right now. Pluto doesn’t have much of an air blanket, and it changes over the course of Pluto’s orbit as the tiny iceball approaches and recedes from the Sun. Pluto reached perihelion, the closest point in its orbit to the Sun, in 1989, and is slowly drawing away again. You might think its atmosphere would start freezing out, getting thinner. But that’s not happening; it’s getting quite a bit thicker.

  However, this is not totally unexpected. Changes are not instantaneous, and it may take a while for things to thaw. It’s possible that only now are gases frozen on Pluto’s surface starting to evaporate. It’s a weird planet, tipped way over (Earth is tilted 23 degrees, while Pluto is canted at 122), and the orbit is highly elliptical and tilted, too. You expect weird stuff from it, and a delay in the thawing is not all that surprising.

  Plus, let’s think about this: Pluto is more than 30 times farther away from the Sun than the Earth is. If the Sun were warming up enough to affect Pluto at that vast distance, it would blowtorch the Earth. If the effects of Earth’s global warming are subtle enough to argue about at all, then it’s safe to assume the changes on Pluto are completely irrelevant to the argument.

So where does that leave us? When I look at all of this, I see a handful of the 100 large solar system bodies showing some evidence of local warming (Jupiter’s spot), some evidence of systemic warming with known causes that are a lot more likely than the Sun heating up (like well-understood orbital variations), and some evidence that any warming experienced by these bodies is possibly being exaggerated in the reporting.

I also see cherry-picking, with no mention of the other planets and moons in the solar system.

And what of the Sun? Is it possible that the Earth’s warming is caused by our nearest star?

Of course it’s possible. There are links to the Sun’s behavior and Earth’s climate (look up the Maunder minimum for some interesting reading), and it would be foolish to simply deny this. However, this is a vastly complex and difficult system to understand, and simply claiming "Yes it’s due to the Sun" or "No it’s not due to the Sun" is certainly naive.

But we do have some facts:

• The Earth is getting warmer.
• We are dumping more CO₂ and other greenhouse gases into the atmosphere.
• A little greenhouse effect is a good thing (otherwise the average temperature of the Earth would be below the freezing point of water). Too much, however, is Venus.
• Some of this global warming is due to human causes. This is fact. The question is, how much?
• There are political and ideological ramifications of global warming, and a lot of people — politicians, in fact — have a lot at stake and are known to twist science to meet their needs.

With all of these facts lined up, it’s clear that the one thing we need to do is be very, very careful when someone comes in and makes a broad, sweeping statement about global warming’s cause, especially when they have ulterior motives for saying what they do. This may sound like an ad hominem, but we have seen, over and over, how science gets abused these past few years by those in power. A jaundiced eye is critical in science, and a little skepticism — or in this case, a lot — is a good thing.

Fire image courtesy of home-and-garden.webshots.com. Mars and Jupiter images from Hubble.

Jimmy Doohan, the actor who played Scotty on Star Trek, had a small portion of his ashes launched very briefly into space this morning. The rocket, supplied by UP Aerospace, went up about 72 miles, which is officially considered to be "space", so there you go.

I’m still not sure what to think of all this (my original musings are here). But in the end it does help promote space travel, and that’s probably good.

The political blog DailyKos has a weekly science section written by a man known only as DarkSyde (though leads to his identity aren’t all that difficult to turn up). This week’s post is interesting: he put up a very pretty illustration by artist Karen Wehrstein of what the sky might look like from Gliese 581c, the planet recently discovered that is slightly larger and more massive than the Earth.

To my delight, he makes it clear this is pure speculation based on the little we know about the planet, but there is enough in the image to spark the imagination (I’ll note that he and I corresponded a few times over what should be in the picture). Red dwarfs are notoriously active stars, with magnetic fields that drive flaring activity on the surface and corresponding starspots. However, they are not flattened– that’s an atmospheric effect, just like how the Sun and Moon look flattened when on the Earth’s horizon.

Adding that was my idea.

At the distance of the planet from its star, the red dwarf would be bigger in apparent size than the Sun is in our skies, and the total brightness would be higher. However, the surface brightness would be lower — the amount of light you see from the star per square degree. Hanging low on the horizon, with the Moon Illusion in full force, the star would look positively enormous, glowering, and surface features would be easier to spot. It would be very dramatic, and incredibly beautiful.

Ms. Wehrstein has some more artwork of the night side as well, speculating on how things might look there too. Some folks might protest this sort of thing; letting our imagination run ahead of our science. In fact, I support this. As long as people understand it is speculation and not necessarily reality, this lets us visualize these alien vistas and maybe spur us on to think more about what circumstances really are like in such places. Who knows who will be inspired by such artwork, then go on and study the real thing?

The Stratospheric Observatory for Infrared Astronomy, or SOFIA, is an infrared telescope that flies - no joke — aboard a 747 airplane that has a big hole cut out of the fuselage. It’s the follow-up mission of Kuiper, a very successful but smaller telescope that took lots of great data from the cargo class section of a modified C-141.

SOFIA is a much bigger ’scope (2.5 meters), and so will do much better work. It almost didn’t though. During the notorious reign of NASA’s Associate Administrator of the Science Mission Directorate Mary Cleave (who is gone now), SOFIA was moments away from being axed. But pressure from scientists and others got SOFIA a reprieve, and things got better from there.

Yesterday, it flew for the first time on a test run from Waco, Texas:

See the bulge in the back of the fuselage? That’s where SOFIA sits. A door will open to expose the telescope to the sky (it didn’t on this test run). The plane flies pretty high up for observations, above most of the water vapor in our atmosphere that blocks infrared light from space. The plane, surprisingly, is pretty stable, and gives a great platform for observing. NASA has more info.

This is very exciting. One great thing Kuiper did, and SOFIA will continue to do, is allow teachers to go up with the plane and make observations. And when they land, they go back to the classroom and tell their students how totally cool it is fly on a NASA jet with a honking big telescope. And this way, one by one if we have to, we infect teachers — and their students — with the joy of science and astronomy.

Yay!

The AstroDyke asks an interesting question: if NASA only has funds in the next Hubble servicing mission to repair either STIS or ACS, which should it be?

My vote should be obvious: I worked on STIS for 5 years. But it’s not just loyalty: Hubble lacks a good UV camera right now, and cannot take decent spectra at all in the optical or UV. ACS is a fantastic machine, but I think (I need to do more research, admittedly) that WF3 will cover a lot of the same ground sky.

So what do you think? Leave comments on her blog; give her some love.