Between the high cost of fuel, and the environmental impacts of fossil fuel use, fuels derived from biological sources are receiving a lot of attention these days. But how efficient are they, and what are the hidden costs (both financial and ecological) of their production and use?

After a break (thanks to a surge of activity at work and home), SOS is back -- this episode, with a two-threaded take on recent events on the red planet. Tune in to hear both the human and geological history of water on Mars, and a bit of background on the argument you'll hear running in the background in related press releases.

In episode 18, I talked about the development of evolutionary theory leading up to Darwin and his contemporaries. Now it's time to turn to the man himself -- so with the background... well... in the background, I'll talk about what Darwin did and didn't do. I'll also talk about a number of cases in which people in subsequent centuries have (and continue to) wrap various other theories in Darwin's name -- in attempts to either win their theories some respect, or to smear Darwin and his work.

Today, the 12th of February, 2008, is the 199th anniversary of the birth of Charles Darwin. Since this has been dubbed "Darwin Day," and all sorts of events are planned for the upcoming year commemorating Darwin's turning the "big 200" (as well as the 150th anniversary of the publication of his "Origin of Species") in 2009, I thought it'd be a good time to discuss how evolutionary theory became what it is today, and what Darwin's unique contributions to the theory really were. In part one, we'll talk about the development of evolutionary theory leading up to Darwin and his contemporaries.

While sorting through pictures for some "Scientific tourist" blog posts, it occurred to me that two of them together told an interesting tale. Listen in on this episode, and find out how two craters -- one in Arizona and one in Bavaria -- helped a man named Eugene Shoemaker reshape how geology is conducted, and invent the field of planetary geology as a scientific discipline.

Between discussions of global climate change, and the ever-rising cost of energy, people are taking a hard look at the costs of lighting. Listen in to this episode, and I'll attempt to (ahem...) enlighten you on the history and potential future of this technology.

There's been a recent surge of news about solar activity and the solar cycle -- and of course, variations in solar activity always seem to get brought into discussions of climate change. Listen in this week, and I'll give you some quick background on solar physics, the solar cycle, and how it all impacts us in the end.

If you're like many people, you'd like to help do something about climate change through the choices you make and the way you live. Celebrities and the mass media (among others) are presenting hybrid vehicles as a big step forward in this regard. But left out of this rush to technology is any discussion of the fact that not all hybrids are equal. Some are little different from conventional cars, and consume fuel with equal gusto. Others offer dramatic improvements in fuel economy, but may not appear at your local automotive dealer's showroom floor for years. What's a well-intentioned, but budget-minded potential car buyer to do? Listen in to this episode, and I'll give you a quick education in hybrid vehicle technologies. You'll be able to tell series from parallel, and electric from hydraulic with aplomb -- and more importantly, understand some of the challenges that lie ahead for this technology, and how to tell when a hybrid vehicle's price premium makes it a worthwhile investment. This episode is the first in a series on ways you and I can help fight climate change.

If you've been following the news at all lately, you've probably heard an earful about James Watson -- Nobel laureate, co-discoverer of the structure of DNA, and never ending source of nausea-inducing, off-the-wall statements. Watson stirred up a bit of controversy lately by essentially stating that people of African descent aren't as intelligent as people of European descent. Predictably, most media outlets focused on the dramatic and controversial aspects of the whole affair. Only a few bothered to explain that aside from being insulting and hurtful, Watson's comments have precisely zero basis in science. Listen to this episode, and I'll lead you through the messy and emotionally charged terrain of race, intelligence, and genetics.

Today is the 50th anniversary of the launch of Earth's first artificial satellite -- Sputnik 1. Lots of news sites are covering various aspects of this anniversary -- mostly dealing with what's happened in space in the intervening 5 decades, and what we may see in the future. What seems to be getting far less coverage, though, is the twisted path that led to the launch. Sputnik's launch didn't take place in a vacuum (no pun intended), after all -- a number of social, political, and technical forces were at play. Listen to this episode, and I'll fill you in on all of the good "deep background" information that's often lost in the shuffle.

Listen to this episode, and you'll learn about honeybees, how important they are to modern agriculture, and how damaging something called Colony Collapse Disorder (CCD) has become -- at least, in the U.S. and Europe. Also, some recent developments in the study of CCD have received excited (if uneven) press coverage. I try to put the news in a bit of perspective, and talk a bit about the work that still needs to be done.

Now that we've dispensed with the preliminaries, it's time for some much odder physics than you're likely used to -- we're getting down to the sub-atomic level with quantum mechanics. This week's episode is the third in a series on post-Newtonian physics -- and none require you to do any math. If you're new to the podcast, you'll want to check out episodes 4 (Physics: A Brief History, 6 (Special Relativity), and 8 (General Relativity) first, just to put this material in context.

Stem cells -- everybody talks about them, but how much do all these talking heads really know about them? Listen in to this episode, and you'll get a basic background in stem cells, and why you should care about them. What stem cells are, what they're useful for, what kinds have ethical concerns attached, and which shouldn't -- it's all in here for your listening pleasure. I also talk about some promising new news from Japan -- the dawn of guilt-free stem cells may be just down the road.

Now that we have some of the preliminaries out of the way, it's time to take a quick look at General Relativity. Fortunately for the physics impared, it's actually a bit easier to get your head around than is Special Relativity -- and you get black holes, the big bang, and gravitational lensing in the bargain! This week's episode is the second in a series on post-Newtonian physics -- and none require you to do any math. If you're new to the podcast, you'll want to check out episodes 4 (Physics: A Brief History) and 6 (Special Relativity) first, just to put this material in context.

Now that you have a little background on the history of Neanderthal studies from episode 5, it's time to dig a bit deeper. This episode is all about how we may be related to them -- as ancestors, or just distant cousins. Recent advances in technology have made it easier to tease information from ancient bones, and I'll lay it all out for you in 20 minutes.

So, you may be asking, what's so special about relativity? As preparation for some future episodes, you'll need at least a little background in modern physics. So this week's episode is the first in a series on post-Newtonian physics. If you're new to the podcast, you'll want to check out episode 4 (Physics: A Brief History) first, just to put this in context with its historical predecessors.

As a prelude to some episodes on human evolution and our historical relatives, I thought it would be helpful to start out with a bit of history. So this episode is devoted to the history of Neanderthal discoveries, and how those discoveries were viewed culturally.

In future episodes, I'll be talking about various turning points in our understanding of the universe around us -- so it made sense to me to start with a little historical context. From the first theories of the solar system to the "theory of everything" in under 27 minutes!

Anti-evolution forces like to make a lot of noise about fossils, in particular about how we don't have a continuous set of fossils showing every step in the evolution of every species on the planet. What they're misunderstanding is that it's hard to make a fossil in the first place -- and harder still to guarantee you'll find it even if it survives for long (the Earth is a pretty big place, after all). So this episode is all about fossils -- how they're made, why there are occasional "gaps" in the fossil record, and the interesting way in which culture and mindsets have shaped our view of fossils over the years.

Since the fourth IPCC (Intergovernmental Panel on Climate Change) report is in the process of being released, I thought it'd be a good time to give everybody some background. So this episode is devoted to the basics of climate science, as well as a very brief history of the field. In a future episode, I'll walk you through the IPCC report itself.