I’ll be “liveblogging” on a delay tonight, but I will post my thoughts. Stay tuned…
Finally starting now. Pretty psyched about tonight based on the title, because my own career got started in the clean room of Ariel Anbar.
Also, because I’m starting late I’m ditching Twitter for the night and will just post my thoughts free-form here. That means less pictures and more text.
“There was once a man who went searching for the true age of the Earth…”
That’s how we open! Excellent. We’re finally on geology, my “home discipline.”
I suspect we’ll be talking a bit about radiation and radioactive elements tonight. 🙂
The part about the formation of planets around the Sun still has a lot of unknowns associated with it. We’re finding out a lot from our discoveries of other planetary systems from the Kepler mission and ground-based observations… but we there are still HUGE holes in our understanding of how fast certain parts happened.
“… until we turned to another book to find the age of the Earth.” (Hint: that other book is Earth itself.)
The imagery of the Grand Canyon is fantastic. And oh man Tyson pulling apart the layers to demonstrate the geological history of North America is really, really well done.
Degrasse Tyson is pointing out the degree to which we can’t use the thickness of layers to date the Earth. However, it’s important to note that the order of these layers can give us “relative” ages – in other words, it can tell us the order of events even if the absolute dates aren’t known.
As with a lot of the other images of meteors you see on TV and in movies, these appear too close to one another.
Meteor Crater, AZ. Cool. Been there. In addition to giving you a sense of the power of astronomical events, it’s a great hike. And there are some nice fossils there, too. 🙂
This is a great analogy to explain radiometric age dating: the uranium atom is nature’s unbreakable clock. And how you can use the decay products to measure the age of meteorites, and thereby get at the age of Earth.
“Now I know you’re no geologist. You couldn’t tell granite from feldspar. But I hear you really know your way around a mass spectrometer.” Sounds like my kind of geologist. Hehe.
The struggles Patterson went through in finding lead contamination in his experiments is a fight continued to this day by geologists and spacecraft engineers. This is why clean labs exist.. . for both geochemistry and for creating instrumentation for spacecraft.
How to clean labs work? They usually have three principles: first, you set up fine filters to ensure no particles enter through duct work. Then, you have the room be at a positive pressure to the rest of the building so that air is always flowing out of (and never into) the room. Finally, you put in protocols like specific shoes or shoe coverings and the lab coats you see people wear, to minimize the degree to which foot traffic brings stuff into the lab.
“I’m going to ionize you.” He was ionizing the elements to introduce them into the machine (the mass spectrometer) that measured how many atoms were in the sample that had the mass of lead.
“The world is four-and-a-half billion years old. We did it…”
I’m still stunned that a species on this planet can calculate the age of the planet.
This bit on the dangers of lead is a great example of how research in the history of Earth can have profound implications for our society – in this case, human health.
These “scientific concerns” about the dangers of lead sound eerily familiar to those that study climate change on Earth. (Yes, this is intentional. Foreshadowing to a future episode, I strongly suspect.)
Patterson’s quest to discover the cycles of lead on the planet are a classic example of how geochemist’s study the entire periodic table. And his discovery of the high concentrations in the surface ocean marked a turning point in our understanding of human contributions to global element cycles.
Note the critical role – the ABSOLUTELY CRITICAL ROLE – public funding of science played in Patterson’s story. Private funding for the research dried up as soon as his research uncovered problems with petroleum products. So who stepped up to the plate? The army. The Navy. The Atomic Energy Commission. The Public Health Servce. The National Science Foundation. Basically, the uncompromised, unbiased funding from the US government. The lesson Rome should have learned is one we DID learn, in large part due to that funding.
For a second I thought they did a great deal with Senator Muskie’s Maine accent… then I realized we’ve now reached a recent enough era of science history where they’re probably using a recording of the hearing. Heh.
“You’re saying the same numbers are leading to different conclusions? Yes.” Sounds very, very familiar. People often use the tobacco industry as an example of how science can be bastardized and undermined by those seeking to protect profits, but this is an equally good (if not better) example, because of the strong ties to how our society put lead into the environment….. and how that lead could have had strong negative impacts on humans.
The show closes with an illusion to climate change, but this could have been stronger in my mind. Hopefully they’ll come back to this all-important topic.