Cosmos - The Lives of Stars

If you want to make an apple pie from scratch, Carl Sagan famously argued, you must first invent the universe, and for that, you're going to need stuff. But where does the matter that make up the cosmos come from? How is it created? If all matter is composed of three tiny particles (protons, neutrons and electrons), how do we explain the diversity of matter all around us?

In this installment of the widely celebrated documentary series Cosmos, Carl Sagan explores the origin of the chemical elements, how these relate to the birth, growth and death of stars, and even a little general relativity for good measure.

For more on the nature and origin of the elements of the periodic table, check out Jim Al-Khalili's wonderful documentary series Atoms (parts 1, 2 and 3), or his history of chemistry (parts 1, 2 and 3).

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We're Not Home, E.T. Please Leave a Message...

Are we alone in the universe? I have no clue. My guess is that we probably aren't, but the odds of ever finding other forms of intelligent life are so small that one may wonder why we have SETI in the first place. This is one of those strange cases in which a complete absence of evidence is no evidence of absence... unless it is, but then how would we know the difference? (As you can tell, I'm somewhat ambivalent on this issue).

SETI has recently had to deal with some major cuts to their funding, and although I don't expect us to find intelligent life outside of our planet any time soon (it's hard enough finding it on this planet), I don't think that the program should be closed, or even reduced. Its importance to me isn't about whether it manages to hear from E.T. It's about a certain conception of human vision and curiosity. To me, keeping SETI alive, or closing it, says more about us than it does about possible aliens, so the question really boils down to what we want to think of ourselves...

But even if we ignore that, Carl Sagan has some words, inspiring as ever, concerning the importance of this kind of research.

And as you can tell, this is not a new issue. Carl Sagan already addressed it in his book Contact:

And seriously, the budget for SETI is really a drop in the bucket. It's not like we're talking crazy amounts of dough here...
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Cosmos: Travels in Space and Time

Continuing his exploration of the Cosmos, Carl Sagan takes us today on an exploration of interstellar and time travel, the likes of which no human being has ever actually experienced so far.

In order to explain this idea, and after giving a quick lesson on constellations, he goes to the Tuscany area of Italy (home of Leonardo da Vinci and childhood residence of Albert Einstein), and conducts some thought experiments in order to illustrate the strange consequences and apparent paradoxes of Einstein's theory of special relativity.

With a basic understanding of the physics involved, Sagan then turns his attention to the possibility of future travel to other stars and galaxies. Although this is a sound theoretical possibility, the engineering required to make this a reality is still nowhere in the foreseeable future yet, but scientists are already coming up with ideas about how to get started...

Check out the rest of Carl Sagan's Cosmos.
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