Tuesday Morning Quarterback:

Subramanyan Chandrasekhar, one of the leading 20th-century astronomers, won a Nobel Prize for his 1930s studies that maintained the most common category of exploding stars, called the Type Ia supernova, could not exceed about 1.4 times the mass of our sun; this seemed to impose an upper boundary on the amount of destruction such a supernova explosion could cause. But the Toronto researchers observed a Type Ia supernova, dubbed SNLS-03D3bb, that reached about two solar masses before detonating, and thus released far more radiation than was thought possible. There’s another implication. Partly owing to Chandrasekhar’s arguments, it was assumed all Type Ia supernovae explode with about the same luminosity, meaning their light level could be used to estimate the expanse between the Milky Way and distant galaxies. (If they’re all giving off approximately the same amount of light, relative measurements allow you to estimate how far away they are.) Current estimates of the size and age of the universe, and its rate of expansion, rely on the assumption that Type Ia supernovae obey the Chandrasekhar limit. If it turns out this class of exploding stars varies significantly, all bets might be off about how large and old the universe is, or its rate of expansion.

Now consider this. Since Edwin Hubble’s discovery in 1929 that the universe was not static but expanding, theorists have debated whether the expansion would continue forever, gradually slow down or eventually reverse as gravity overcame the outward momentum of the Big Bang and pulled the stuff of the firmament back to its starting point. (The latter conjecture is called the Big Crunch.) Researchers using Type Ia supernova as measuring sticks declared in 1998 that cosmic expansion was accelerating, which nobody’s theory predicted. The galaxies could not be speeding up unless energy were somehow being added to them, which caused cosmologists to speculate that mysterious “dark energy” permeates the universe and functions as the mirror image of gravity. No physicist has offered even the vaguest explanation of where dark energy originates or what powers it. (General relativity theory does offer an explanation of how gravity derives its power to pull.) Yet even though the dark energy concept requires you to believe that most of the energy of the universe is undetectable and so far inexplicable, physicists rapidly have accepted the idea that dark energy exists and even might be the dominant force of the cosmos. What if it turns out the universe is not accelerating, that the apparent rising rate of expansion is a data error caused by the false assumption that all Type Ia supernovas have a standard brightness? Then physicists will have to announce that dark energy never existed in the first place. But trust us, we’re experts!

Yes, I really got that from an ESPN.com football columnist. But he writes about much more than just football.

And this sort of thing is one of the reasons why I love science and why I’m decidedly skeptical of science. I love it because it’s an endless pursuit of knowledge. And the sorts of things we know now that we didn’t know even 20 years ago are just staggering. But the things we don’t know now that we thought we knew 20 years ago (or last week) is also staggering.

Yet many people claim with great certainty that the universe is 15 to 20 billion years old (or 6000 years old) or that whales evolved from land-based animals like pigs or cows about 45 million years ago. Nobody really has the foggiest idea precisely the age (even within a margin of a few billion years!) or size of the universe. And unless I’m missing something there’s no real evidence that Shamu is Porky Pig’s distant offspring.