The right sky

Jen over at Twisted Physics and Cocktail Party Physics has recently set up SEEx- a translation service which allows speakers of science and media to communicate with each other. In her introductory blog, she mentioned the story of Neil Tyson and the wrong sky. In short, Dr. Tyson complained that despite getting all this historical trivia about the Titanic correct- which nobody would notice, much less care about, they screwed up the starscape that was visible after the ship sank. The thing that ticks me off about this is that it is trivial to do correctly. Fifteen minutes browsing the web (even the 1996 web) would have found them a downloadable program that would inform them that the survivors of the shipwreck would have seen this:

The habitable planet bubble

Greg at Oklo.org has recently put a price on terrestrial planets, as the successful launch of the Kepler telescope has piqued various people's interest in these worlds. More recently, he has announced a prize for the first planet to exceed a million dollars on his pay scale. Just for comparison's sake, he rates the Earth at 4 quadrillion dollars on this scale, while the small, cold Mars comes in at a paltry 13 grand. No currently known exoplanet can even match this value, with Gliese 581b maxxing out at just over $500. However, there is at least one low hanging fruit.

A few weeks ago, coming home from work just after sundown, I noticed a bright terrestrial planet hanging low in the western sky. As I am a women's tennis fan, I decided to name this planet after my favorite player.

The value of Venus in the oklo.org valuation is strongly dependent on its calculated blackbody temperature, which in turn depends on albedo. Using the known value of 0.75, the blackbody temperature of Venus is -40 degrees C, which is chilly, but still close enough to habitable to return a handsome 348 trillion dollars.

Assuming an albedo of zero raises the temperature by almost 100 degrees to a toasty 55 degrees C. This impacts the valuation considerably, giving a total value of only 81 trillion dollars because the planet is too hot. But 0 and 0.75 are both extreme values for albedo. What if we use something more moderate?

The purpose of the exercise is to find terrestrial planets, so assuming a terrestrial albedo (0.36) seems to be the most reasonable place to start. This assumption gives an average Venusian temperature of 20 C. That's an almost identical to the current temperature here in Canberra, and a pleasant 68 F for American readers. Plugged into the valuation formula, this model for Venus returns a staggering 1.44 quadrillion dollars. In fact, this valuation is only 20 trillion dollars short of the 1.46 quadrillion dollar value derived for the Earth using the known terrestrial albedo number. This value also puts me clear of the million dollar jackpot threshold by about nine orders of magnitude.

Of course, pedantic observers may note that Venus's blackbody behavior is tempered by the fact that the planet has a thick atmosphere, which warms the surface via the greenhouse effect. We can calculate this second order effect by substituting T_eff (the model blackbody temperature- 230-330K depending on albedo) with T_real, the actual surface temperature of 737K. This drops the valuation from 1440 trillion dollars to 2.9x10^-89 dollars, or 2.9x10^-87 cents. But in the current financial environment, a mere 104 order of magnitude decrease is not a problem. Rather, it is a badge of honor. Who wouldn't want ten thousand googles in times like these? Were I an investment manager instead of a geologist, I could use that as a justification for a million dollar bonus paid by congressional bailout.

Compared to this planetary overvaluation, the housing bubble is imperceptible.

Here are the values for some other solar system objects:
Moon: 7x10^-25 dollars. (size matters)
Europa: 7x10^-47 dollars. (This makes the JIMO EJSM program 56 orders of magnitude over budget)
Ganymede: 1.2x10^-37 dollars. (The European half of that mission is relatively thrifty)
Titan: 9.5x10^-44 dollars. (compare this with Greg's hypothetical exomoon)

No more shots this decade.

LLLL is all done her shots until she is four. Hooray. Vaccinations are one of those things that are mildly traumatic at the time, but good for everyone in the long run. Kinda like school, and exercise. Except that shots don't just protect your kid, they protect everyone else's as well. And that's sort of what community and civilization is all about.

Wool socks have carbon footprints

There have been several insinuations that the production of beef for food is particularly problematic with regards to greenhouse gas emissions. In addition to the resource cost associated with meat in general, beef is single out because cows allegedly generate a lot of methane, as a result of being ruminant animals.

This makes me wonder, where’s the outrage against other cud chewing creatures. There are plenty of other ruminants who seems to be getting a free pass here. For example, if a juicy steak is considered by activists to be a glacier-melting extravagance, then what is a wool sweater?

As of 2002, Australia had 100 million sheep, but only 26 million cows, a ratio of 4:1*. As the cows have greater total mass, the sheep contribution is probably half to a quarter that of cows, depending on the which numbers you pick. In NZ, where the sheep/cow ratio is higher, the little bleaters account for almost half of the country’s entire weighted emissions. And hamburgers cannot be replaced by a lighter, warmer substitute synthesized from recycled plastic bottles. So if you want to get serious about the ruminant problem, phasing out wool seems to induce a much smaller decrease in standard of living than reducing the cattle herd.

Of course, there are some people who simply prefer animal-based fibres to synthetic ones, just like many people prefer meat protein to squashes and beans. The links above suggest that switching from cattle to non-ruminant meat sources like kangaroo, pork, and chicken would provide a substantial benefit. There is no reason that lovers of animal fibre clothing cannot do the same. After all, rabbits aren’t ruminants. Neither are foxes or mink. So getting all those woolen clad activists to switch to fur coats would probably reduce anthropogenic methane emissions.

So next time you see someone decrying beef stroganoff and large clunky American cars,** check out their threads. Because wool socks have big carbon footprints.

* As the current drought is more severe in sheep country than cattle country, this ratio may have dropped since then.
** Is there another kind?

Happy International women's day

Here's a very simple reminder of the contributions that women have made to the understanding of the Earth:

Science by Earmark

To all those people whinging about John McCain's criticism of earmarks for scientific research:

When science funding is chosen on that basis of legislator's pet projects, and not by a peer review system, you get projects like this.

Your grandkids are going to be paying interest on that funding. Assuming that they don't die from measles first.

I'd love to see stats on citation rates comparing earmark 'science' vs competitively awarded science. Anyone with a handy link to such information?

Space posts in February

Carnival of space 89
Carnival of space 90
Carnival of space 91

Fermi paradox meets the timescale

John over at cosmic variance has been discussing extra-terrestrial life, so I figured I'd put a geologic spin on it. Specifically, look at the Fermi Paradox through the lens of deep time. The Fermi paradox states, "If advanced aliens are common in the galaxy, where are they?" More specifically, why aren't they here. As a geochronologist, I don't wonder where and why, I wonder when. So let's make a few assumptions:

Suppose that Earth has been visited by aliens 50 times since our solar system's accretion disk started to cool 4,567 million years ago. What would the aliens have seen? In order to simulate this, I generated 50 random alien arrival times in between then and now, sorted them, and put them in geologic context. They are listed below, in stratigraphic order.

Time (Ma)	Time (name)	My comment	Alien's comments
125	Cretaceous	Dinosaurs!
270	Permian	Gondwanan glaciers and funky reptiles
352	Carboniferous	Swamps and really big insects
668	Cryogenian	Pre-Marinoan- no sponges yet
675	Cryogenian
701	Cryogenian
748	Neoproterozoic
750	Neoproterozoic
808	Neoproterozoic
925	Neoproterozoic
1021	Mesoproterozoic	Grenville	Big Mountains
1049	Mesoproterozoic	Grenville	Big Mountains
1300	Mesoproterozoic
1355	Mesoproterozoic
1533	Mesoproterozoic	Mt Isa is forming	If these aliens came for resources, they didn't want base metals
1684	Paleoproterozoic
1857	Paleoproterozoic
1888	Paleoproterozoic
2159	Paleoproterozoic	Trans-Amazonian orogeny
2247	Paleoproterozoic	Various poorly constrained glaciations in this general timeframe
2272	Paleoproterozoic	Various poorly constrained glaciations in this general timeframe
2355	Paleoproterozoic
2358	Paleoproterozoic
2400	Paleoproterozoic
2459	Paleoproterozoic	Oxygen just starting to leak into the atmosphere, Manganese and BIFs
2610	Neoarchean
2612	Neoarchean
2631	Neoarchean
2661	Neoarchean
2682	Neoarchean
2745	Neoarchean
2948	Mesoarchean
2956	Mesoarchean	These two mesoarchean visitors missed each other by only 95,000 years.
2956	Mesoarchean	These two mesoarchean visitors missed each other by only 95,000 years.
2972	Mesoarchean
2990	Mesoarchean
3152	Mesoarchean
3281	Paleoarchean
3609	Eoarchean
3614	Eoarchean
3641	Eoarchean
3647	Eoarchean
3669	Eoarchean
3828	Eoarchean
3837	Eoarchean
3875	Eoarchean	LHB	Dynamical instability of this system precludes the development of complex life
3947	Eoarchean	LHB	Dynamical instability of this system precludes the development of complex life
4011	Hadean
4266	Hadean
4425	Hadean	Moon forming impact	"That's not a moon, that's a battlestation"

As you can see, for aliens looking for 'Earthlike' planets, the actual Earth was easy to overlook for msot of its history. In this simulation, there was only macroscopic life for 3 of 50 visits. From another POV, three visits were eaither during the Late Heavy Bombardment, or during the moon forming impact- both of which would appear (to the casual alien visitor) to make long-term viability of life on Earth pretty unlikely.

So as we start to find 'earth-like' planets in our sky surveys, it is important to remember that Earth has only been Earthlike for a relatively short period of time.