I saw Sirius in the daytime

Three minutes before sundown, to be exact, while the sun was making all the hilltops pink and pretty.

I read that it was possible under good viewing conditions, and a few weeks ago the Bad Astronomer posted about spotting Venus in the daytime. Canberra is dry and 600 meters high, and this time of year the star is just north of straight up at sundown. So, I went out last week to line it up with a telephone pole. Then I went out progressively earlier each clear day to try and spot it. Sunday I caught it 5 minutes after, and yesterday was brisk and clear high pressure, with just a few high wispy clouds to focus on. I tried half an hour before with no luck, but at 5:52, it was right where it should be, twinkling between the wisps of cloud 8.7 light years below.

I had a brief look for Canopus, which is just a bit south of due up, but it is substantially dimmer, and I haven’t lined any landmarks up. Still, it is cool to confirm that the stars are still there during the day, even if they can't quite shine through the fuzzy blue atmosphere.

Moonrise over Telstra Tower

This is Canberra at night.


I've had a reader ask for more pictures. Anything else you folks would like to see? The request line is open.

Tsunami warning on the radio

There was a tsunami warning on the radio this morning. Evidently the Solomon Islands event triggered the regional network, so all the boffin-to-yobbo communication networks sprung into action. Since Canberra is 100 km inland and 600 meters above sea level, I didn't pay it much attention, but evidently the wave height on the coast was 10-20 cm.

Not exactly a city-destroying wave of doom, but better to try the new system on one of these than a M 9.5 monster or a caldera collapse on the Kermedec. The main problem was that in Sydney, all the tourists flocked down to the shoreline to see why all the ferries stopped and the harbor was cleared. Go figure.

I haven't had a chance to find the USGS report, or to look up relief agencies, but a NZ or Australian news search should get you to the latter.

Relativistic Obesity

The obesity epidemic in America has reached relativistic proportions, with some overweight citizens gaining so much weight that they distort the space and time around them. As the photo below demonstrates, the largest Americans are now capable of gravitationally lensing their suburban environments.



According to the surgeon general, this represents a disturbing new trend in the fattening up of America. All previous dietary guidelines and predictions have been based on Newtonian physics. Researchers never imagined that people could shovel enough food down their gullets to perturb the space-time continuum. This recent development shows that it is actually possible for human fat cells to gravitationally collapse into degenerate matter.

Naturally, fat groups are outraged. “This is just another facile ploy to blame individuals of stellar mass,” said Julius Gloop, spokesperson for Fat Pride. “We are being victimized by an anomalous law of physics, a law that doesn’t even have the decency to abide by the Standard Model.” Mr. Gloop then struck out at the term “degenerate matter”, claiming that such base and unsubstantiated slurs were not conducive to a healthy debate of American’s eating habits.

“Degenerate to whom? To chemists? To plasma physicists? Obviously this sort of electron shell elitism serves only to denigrate the working poor who can’t afford gym memberships and organic cranberries.” Mr. Gloop then demonstrated that this so-called degeneracy was a boon, as his weight gain actually reduced his pant size, due to the effects of gravitational self-compression. Some physicists found this trend worrying, however.

“There is a practical limit to the amount of weight a person can gain,” said professor Alfred Gauntly of Queanbeyan State University. There comes a point where the carbon and oxygen atoms in fat cells get so close together that they undergo a runaway fusion reaction, producing a spectacular nuclear explosion known to astronomers as a supernova.” The effect of one of these explosions on a typical suburban mall would be rather disruptive. But where some scientists see danger, others see opportunity.

“For years, science has been trying to find a way of rapidly transferring mass in order to measure gravity waves,” countered professor Max Higglebotham of the Nebraskan Oceanography Institute. By compressing some of the relativistically obese into a critical mass, we could create those conditions in the lab, thus testing fundamental theories of gravity.” Indeed, until the widespread adoption of junk food and sedentary living in the western world, scientists did not have the means to grow PhD students who not only blocked out the light, but actually made it bend out of their way. Now these students are in hot demand. “The only problem,” said professor Gauntly, “Is finding ways to maintain their mass during a 6 year PhD program, where all they can afford to eat is Raman noodles.”

Hat tip to cosmic variance for the link to the lensing site.

If you have to ask...

...you don't need to know.

If the numbers aren't readable in the small pick, click through- the fullsize should be OK.

Which body is in the diamond?

Ok, folks. It is time to get back to some good, old-fashioned quantitative blogging. In her recent diamond blog, Jennifer mentioned Life Gem, which claims to sell diamonds made from the carbon extracted from a deceased loved one. A press release about this process floated through our work a few years ago. At the time, their technique was to capture exhaust fumes from cremation, extract the CO₂, reduce it, and make a diamond. A colleague of mine and I wondered about this. How much of that carbon would be from the body, and how much would be from the fuel used to combust it? We both suspected that such diamonds would contain mostly carbon from the fuel used to burn the body, with only a bit of loved one mixed in.

But why speculate when we can calculate? Let’s do the math, and then discuss how to test the prediction.

Assume a 70 kg body that is 20% carbon (various online sources give values between 18 and 23% carbon for a person).

70kg total x 0.2 C/total = 14kg C

How much fuel does it take to combust such a body? This website says 20 liters, but they don’t specify what the fuel type is. Let us assume it is fuel oil with a density of .85kg/l, and a carbon content of 85%.

20 l x .85kg/l = 17kg total x .85 C/total = 14.5 kg C

So if we are burning the body using fuel oil, the exhaust carbon will be about half body and half fuel.

Natural gas should give less carbon exhaust. According to Wikipedia, the energy density of diesel oil is about 46 MJ/kg, suggesting that 782 MJ are needed for cremation. Using natural gas, with an energy density of 54 MJ/kg, we need only 14.5 kg of gas. Furthermore, natural gas is only 75% carbon, so the total carbon mass from natural gas fuel is about 10.9 kg.

Of course, calculations are all well and good, but how can we test it? In the case of fuel oil, testing is difficult. However, natural gas tends to have a very light carbon isotopic composition, with a ¹³C/¹²C ratio 4-6 percent lighter than PDB (an arbitrary, but universal carbon isotopic standard). In contrast, a body will have a C isotopic content somewhere between 2.1 and 2.8 percent lighter, depending on how careful the person was about watching what they ate.

So if you really want to know how much of your diamond derives from your deceased beloved, and how much is burned natural gas (itself the remnant of long dead organisms), you can measure the carbon isotopic composition of the diamond. There’s just one problem.

Measuring carbon isotopes requires a destructive analysis. So some or all of the gemstone must be consumed. Otherwise, you’ll never really know which body is in the diamond.

Ten young Americans

Note: This is a purely political post. There is no scientific content.

The following ten links refer to news stories about ten young Americans. They are from all over the country, and have quite different backgrounds, but the one thing that they have in common is that they all made the news, often in heartbreaking fashion.

Ming Sun, 20

Milton Gist, 27

Jennifer J. Harris, 28

Hector Leija, 27

Darrell Wayne Shipp, 25

Luis Rodriguez-Contrera, 22

Ashly L. Moyer, 21

Nimo Westhill Masaniai Tauala, 29

Curtis E. Glawson Jr., 24

Barbara Bush, 25

Environmentalists: shilling for Krispy Kreme?

Some typical environmental leader- possibly from the WWF- was on the radio the other day, warning that biofuels are problematic, and suggesting that we might actually all be better off freezing in the dark.

His chief complaint was that biofuels might increase the price of foodstuffs, thereby making life hard for the poor. This is an interesting proposition, one that invites closer analysis. For example, what foodstuffs would most likely be affected?

The obvious answer is that agricultural commodities used for fuel production would be subject to an increase in demand, resulting in an increase in price. If those commodities are commonly consumed by those with limited disposable income, then such people would be forced to switch their dietary habits, or go without.

So, what are the foods most likely to be used for fuel production? At present, the two main biofuels are ethanol and bio-diesel. Biodiesel is made from vegetable oils, while ethanol is mostly made from sugar, with some production coming from feed corn.

Thus, in a biofuel dependent economy, we would expect sugar and vegetable oil (nd to a lesser extent, red meat) to be more expensive, and poor people would have to cut back on these items.

Such an event would be a cultural disaster. The liberal worldview requires a repressed underclass which is forced to poison itself with junkfood by an uncaring economy. Imagine a beleaguered working class breadwinner eschewing his donuts for oatmeal. Imagine the hardship caused by drinking unsweetened tea instead of soda. People might actually start improving their lives instead of wallowing in victimization.

In the developed world today, obesity and diabetes are especially rampant among low income people. Increasing the price of the food items which cause these diseases would disrupt this demographic. It is even theoretically possible that it could reduce the incidence of these debilitating diseases, freeing the victims from a lifetime of suffering and dependence. And nothing threatens liberals more than the possibility of poor folks being less dependent.

So it is no wonder that the greenies are supporting the donut industry. Biofuels could make junk food too expensive for poor people to poison themselves with it. That would be a market triumph. Something that liberals must avoid at all costs.