Depending on where you are, it might be the last thing you see.

Things like clones and identical twins aside, the scientific way to attribute a certain glob of biomatter to a specific person with a high certainty would be DNA analysis.

The problem here is that this scientific way completely fails for fertilized eggs, as their DNA is clearly different from either biological parent.

http://en.wikipedia.org/wiki/N...

There was plenty of CO2 for plants to go around even before humans started burning coal at industrial scales.

This is basically just un-burning coal. And oil. And natural gas.

I'm sure you could run a side-channel attack on the computer for tells, and I'm also sure the computer could be fitted with a camera and appropriate algorithms to read your heart rate, blood perfusion rate, respiration rate, rate of sweat production, etc, for information about your general level of anxiety, surprise, etc.

Experience shows that this effect does not occur to the desired extent.

Less irreversible than execution. Also, it's easier for a person to sue for tons of money for wrongful incarceration than for the estate of a person to sue for tons of money due to wrongful execution.

And suing for lots of money is necessary to motivate the voters/taxpayers to keep the rate of wrongful convictions down. If wrongful convictions aren't freakishly expensive, there's no motivation.

Now let's see:

a) The method requires some skill on the executioner's side.

b) It's messy and doesn't leave a pretty corpse.

c) In some cultural contexts, death by bullet is considered too honorable for criminals.

d) It's quite destructive. If person-to-be-executed wants to donate their body to science, science gets a body with a hole in it and parts missing.

That's because it started out large enough to have quite a bit of momentum.

... except for the pilots of AF447, who watched their plane fall out of the sky for several minutes due to a stall, not realizing that the flight computer switches to alternate law if it doesn't receive valid airspeed input and therefore could not provide stall protection.

In putting your own mask on first, you are thinking of the children. It takes more than one minute for permanent brain damage to occur due to hypoxia, but without a mask, you only have about 15-20 seconds of useful consciousness left in a worst case case scenario.

So, put your own mask on first, then you'll have plenty of time to put the masks on everyone around you, including children and people who didn't know the basics of respiratory physiology.

Even better: If you're suicidal and have a gun, you can just get it over with and shoot yourself. No need to drag 149 people with you in a suicide-by-airplane.

Managing lots of things competing for their attention is what pilots need to be excellent at.