David Kirkpatrick

February 10, 2010

The Drake equation and the multiverse

The well-known Drake equation, created by Dr. Frank Drake in 1960 to predict the number of extraterrestrial civilizations in the Milky Way, gets an upgrade to take into account the concept of multiple universes. Turns out our knowledge is so limited as to make the exercise essentially impossible.

From the second link:

But there’s a problem: this is not an equation. To form a true Drake-like argument, Gleiser would need to assign probabilities to each of these sets allowing him to write an equation in which the assigned probabilities multiplied together, on one side of the equation, equal the fraction of universes where complex life emerges on the other side.

Here he comes up against one of the great problems of modern cosmology–that without evidence to back up their veracity, many ideas in modern cosmology are little more than philosophy. So assigning a probability to the fraction of universes in the multiverse in which the fundamental constants and laws satisfy the anthropic principle is not just hard, but almost impossible to formulate at all.

Also:

Gleiser’s take on the Drake equation for the Multiverse is an interesting approach. What it tells us, however, is that our limited understanding of the universe today does not allow us to make any reasonable estimate of the number of intelligent lifeforms in the multiverse (more than one). And given the limits on what we can ever know about other universes, it’s likely that we’ll never be able to do much better than that.

September 9, 2008

Modified bacteria improves cellulosic ethanol

I’m not completely sold on ethanol in any form, although switchgrass and waste biomass versions are much more appealing than food product biofuel.

If the technology is going to make it in practice, breakthroughs like this will help it get there.

From the link:

New genetically modified bacteria could slash the costs of producing ethanol from cellulosic biomass, such as corn cobs and leaves, switchgrass, and paper pulp. The microbes produce ethanol at higher temperatures than are possible using yeast, which is currently employed to ferment sugar into the biofuel. The higher temperature more than halves the quantity of the costly enzymes needed to split cellulose into the sugars that the microbes can ferment. What’s more, while yeast can only ferment glucose, “this microorganism is good at using all the different sugars in biomass and can use them simultaneously and rapidly,” says Lee Lynd, an engineering professor at Dartmouth College, who led the microbe’s development.