Phoenix Lander on Polygon Structure as seen by HiRISE

(disclosure: I left my cellular internet dongle in my room, so I’m twittering sessions live and posting blog entries on a semi random basis when I can go out and find internet)

I’m leaning against the back wall of a packed ballroom filled with the brim with silent and attentive geophysicists who are absorbing all they can about the Mars Phoenix Lander.

This fairly large (5,5m or 18 ft long) and heavy (350kg or 770lb) spacecraft parachuted to the surface of Mars on May 25, 2008 and poked, prodded and dug into the surface until it froze to death on November 10. While this seems like a short period, the original plan was to wind up operations in August, so the craft had been living on borrowed time. While it is unexpected that the craft will be able to turn back off when it thaws in the next Martian Spring, the lander is programmed to phone home should it survive.

If you want to go back and see what the mission knew in the moment, it’s all recorded on twitter. Check out: http://twitter.com/MarsPhoenix

Today is all about what we can now say with certainty.

The session started with a broad overview of the results everyone was waiting to hear: Is there evidence of past liquid water and is their the possibility Mars can (at other temperatures) support life. The answer is a qualified yes.

For Water:

• The soil Phoenix dug up was clotted/cemented (this is geology speak for what happens when you mix dirt and water, stir, and then let it “dry” out.)
• There is Calcium Carbonate at 3-4% level in some of the samples. This is a mineral that only forms in wet environments
• In addition to Calcium Carbonate, there are other aqueous minerals
• And, to give the most obvious case, there is water ice 5cm below the surface, and this ice is segmented in the same way as a stream that has frozen and thawed and refrozen

For Habitability:

• There are the materials needed to process energy and to get nutrients from the environment
• The 1-2% perchlorate is not a life killer
• The 7.7 pH is friendly

It just happens to be a bit too cold at the moment…

Additional work looking at the variation of ice with depth found that it matches models, and that based on the fact that the rocks aren’t frozen into the ice, but rather are capable of getting flung out of place by casual assualt by alien space laboratories, the ice is old. (Over time the ice contracts, loosening around the rocks).

There was also work that showed that the fascinating polygon structures surrounding the lander are likely caused by seasonal cracking that occurs when the ice contracts and sand and small rocks fall in between the gaps in the ice. The “flat” part of each polygon typically measured 4-5 meters in diameter and have multiple lumps and peaks indicating there is multiple events building these structures. Unlike on Earth, where these can be caused by frost heaves, these patterns are caused by sand wedges.

Sadly, I know need to go play scientist and be part of a telecon. More to come on the other side…

Seriously though, I can sorta kinda get on board with things like regeneration and electric pulses, where the body is doing something some biological life forms can do, but at accelerated rates. The only catch is, generating electricity or regenerating cells requires a LOT of energy, and these folks aren’t using their powers and then chowing down frantically. I have the same moments of broken suspended disbelief with the X-Men and randomly with Jedi. At least Lucas had his Jedi seem to struggle to do things that required energy, and they seemed to get tired using the Force.

Think of it this way, imagine that X-Wing Luke lifted out of the swamp weighed 50,000 lbs (similar to a F14). It would take a little over 222,000 Newtons to hold that thing up! To move it a mere 3 meters straight up at constant velocity would require 666,000 Joules! Excited yet? Well, here’s the sad part: 222,000 joules is the same amount of energy your body extracts from a 160 Calorie can of soda (That’s ~13 ounces worth of Coke-a-Cola). So, if it was possible to convert food energy into pure work without any losses to useless stuff, we could do amazing feats.

But, you are thinking, if it only takes Luke 160 calories to lift that X-Wing, why do I think he should feel starved from the exertion? Well, I don’t think it was a feat that could be done at constant velocity fighting only gravity. There was “friction” from the swamp sucking on the X-Wing and he certainly didn’t move it at constant velocity. I’m betting he easily blew 500 calories on that X-Wing. Give the guy a protein bar!

Part of my annoyance probably comes from reading Marion Zimmer Bradley’s Darkover books at too young an age. Her characters (in some cases) can do telepathy, build things, heal things, etc, using crystals to amplify their bodies’ electrical fields. After doing stuff, they feel half-starved and power eat like a long distance runner. She got it.

I’m not asking for much. I just want hereos to get physically exhausted from using their powers, and maybe even to do a little carb loading or refer to it as a weightloss plan that doesn’t require exercise. Just talk about energy a little bit please. This one small scientific thing you can totally get right just with a Power Bar or two. (And, to lift a 175 lb male 1000 meters into the air at constant velocity would require 187 Calories if you assume no drag – and there is drag folks. And they weren’t going at constant velocity. These guys need to at least break a sweat).

No significant spoilers ahead.

I’m only going to talk about one idea at this point, because I’m still reading. In Ringworld, one of the underlying plot ideas is that the dense stars at the center of the galaxy had undergone a chain reaction of nova, and the light from the nova are going to make life impossible for humans and aliens within the known star systems. At the time of its 1970 publication, astronomers didn’t know what was at the center of the galaxy.
Astronomers (not me, I wasn’t alive yet) knew it was a high-mass region, but we didn’t know how that mass was distributed. Some thought it was high density objects like white dwarfs, neutron stars, and stellar mass black holes. Others suspected a super massive black hole. It was also possible that it was a region of just a lot of normal stars. Because of the intervening dust and gas combined with the high density nature of the region, we just didn’t really have the ability to find out what was there.

In the 1990s, however, technology was employed by UCLA astronomer Andrea Ghez to take high speed images of the center of the galaxy. These images were then aligned and stacked. By taking extremely short exposures, the noise introduced by the atmosphere was overcome. By stacking the images (adding together the light from successive frames), faint objects were drawn out of the darkness. In this case, Ghez and her team have been able to make out the orbits of series of stars (7 are highlighted in the image above) as they orbit an invisible point. This points observationally indicated mass of 2.6 million times the mass of the Sun is confined into such a small area that it has to be a black hole. Nothing else can be that dense.

So, Niven’s image of a dense region of exploding stars isn’t quite as possible as people might have thought in the 1960s (when he was writing it) and the 1970s (when people starting reading it).

That problem aside, Niven mentions gamma rays from supernova almost 30 years before we had the concept of gamma ray bursts being caused by certain subsets of supernova. I know he is just taking about gamma rays in general being given off during SN, but it does raise the question how how would a star be effected if it were in the a star cluster and took the fill blast of a gamma ray burst at close range. I’m going to have to think on that for a while, but it seems that if it were close enough (defining “enough” is the part where I’m going to need to think awhile) external heating could disrupt the normal energy transport mechanism and potential cause a burst nuclear burning in places where it normally would occur. These two effects could definitely disrupt a star in a “I just can’t make ‘er go, Cap’n” kind of way, but just Scotty could always repair the Enterprise, I suspect the star would rebound as well. But again, I need to think on this some more.

Still – neat science. The book makes you think, even if it also is showing some age. I’m sure I’ll have more to say as I continue to read this book and others this summer.