Last week I reported on some strange rocks from South Australia that may preserve the oldest animal fossils. Or may not. Ok, nobody knows. But they look kind of like animals. Read about it here.
I like that the function of the journal article was basically to throw the idea out there, see if any other geologists come across anything interesting. There’s plenty of rock of the right age exposed on the planet; you just have to tell geologists to look for it, and other samples of these animals (or whatever they are) could turn up.
In the I know everybody category, the lead author’s name sounded vaguely familiar. Before I called him I looked at his website, and indeed – he went to Carleton College at roughly the same time as me. We have four friends in common on Facebook. Fifteen years ago, I might even have been able to pick him out of a lineup. Today, his name just sounded vaguely familiar.
Over the weekend, a friend of mine from college asked, via Facebook, how geologists know where an earthquake was. To quote:
Hey Helen, would you please write a blog explaining how geologists can tell where an earthquake’s epicenter is? Are there things stuck in the ground all over the earth? How did they get there? Are they always watching? It kinda weirds me out to think about it.
I took a stab at explaining it on Facebook, based on my foggy memories of 10th grade earth science, then asked friend and fellow science writer Naomi Lubick, who actually has a degree in geology, if she could handle this one. And she did! Here’s her blog post: How to find an earthquake.
The short version: The earthquake sends out waves in all directions, and seismometers measure the waves. If you know when the waves arrive at each place, you can calculate where they came from. But go read Naomi’s post for more about earthquakes, like pretty maps and links and stuff.
A doctor in Lorton heard an explosion in his office on Monday. But it wasn’t an explosion, it was a meteorite. (Read the story in the Washington Post.)
It’s crazy, this business of living on a planet. We go around and around the sun, blundering into bits of asteroids that cross our path. We burn them with our atmosphere, melt the outsides til they’re black and shiny, and catch them with the floors of our doctors’ offices. Then they get to go around and around the sun with us, maybe even – if they’re lucky – with their own unique registration number.
Hi, rock! Welcome to Earth!
UPDATE, 1/22: An online discussion on the Post’s website about this story – hosted by two people I met on this day.
This week I happen to have gone on a lot of geology-related reporting trips around town. I’m sorry I never took geology in college. Carleton has a great geology department, and the geology majors always seemed to have fun. All those field trips, you know.
Actually, the field trips are probably why I never took geology. I had a tendency, when I was in my late teens, to get a little whiny when I was out in the field. I have mostly outgrown this. Or, more accurately, I have grown the ability to tell my whiny self to shut up, and also the knowledge that I must pack snacks. Anyway, as a biology major, I already had to take lots of lab classes, so adding another lab to the schedule would’ve been rough. Especially a lab where you got muddy. (I don’t think the mud would bother me now! See? Growth!)
Anyway, this week I’ve gotten a crash course in geology. Seriously, on Monday when I went on the meteorite visit, I didn’t know what a mineral was. The next day, with the help of Wikipedia and a friend who did major in geology at Carleton, I figured it out. Whew.
Oh, so now you want to know what a mineral is, too? Ok. A mineral is, like, a really pure rock, with a chemical structure you can write down. Kind of. I know, I just gave any geologist readers major chest pains. Don’t worry, I’ll refine this description by the time I have to write my story.
The other day I went to the Smithsonian’s natural history museum to look at some meteorites. It was really cool. I held a piece of Mars in my hand. Actually, two pieces. Of MARS. The PLANET. Which is in OUTER SPACE. These rocks weren’t brought back by a spacecraft – they’re pieces of Mars that got knocked off in some kind of impact, flew through space, hit our atmosphere, and made it to the ground without burning up. Whew.
These, however, are not meteorites:
The boxes and envelopes on the corner of that desk are rocks that people have sent in for the museum’s meteorite specialists to check out. (The big white bag on the right is leftover Halloween candy.) Here’s a tip: If you find a funky-looking rock in your backyard, there’s a really, really, really good chance that it’s just a rock. From Earth.
I even got to see a little piece of this meteorite – the one that made the big “Omg Life on Mars!” splash in 1996. It was in its own traveling case.
Gratuitous beautiful meteorite picture:
This is a slice of a pallasite. It’s like a naturally occurring piece of stained glass – gemstones in a matrix of iron and nickel. I totally want one. But they’re rare and expensive, and I’m pretty sure the museum’s crack meteorite team would’ve noticed if I’d taken this one with me.
This is a slice of a big hunk of nickel and iron that broke off from the core of some asteroid. It was collected in Antarctica. Meteorites fall everywhere on Earth, but they’re particularly easy to find on the Antarctic ice sheet, because there aren’t a lot of other black things. Also, the way the ice moves seems to concentrate them in a few places.
In Bangladesh, millions of people drink contaminated water that’s contaminated with arsenic. This isn’t like in a mystery novel when someone gets poisoned with arsenic. You don’t keel over dead. Water with arsenic in it is lovely and clean and doesn’t need to be boiled – and in the long term, it increases cancer risk as much as smoking.
Today I wrote for ScienceNOW about a new study on arsenic in Bangladesh. Some researchers from MIT think they’ve figured out why some water has more arsenic than other water. Special microbes dissolve the arsenic from the sediment into the water, and they need a carbon source – so the scientists who study arsenic in Southeast Asia are arguing over where that carbon comes from. The new study gives one answer to that question. Read my story here.
In the meantime, people in Bangladesh need low-arsenic water. Filters work, but they’re expensive and need maintenance. Deeper wells tap into deeper aquifers with less arsenic, but they’re also expensive, and as water is sucked out of the deep aquifer, higher-arsenic water could sink down from above.
I thought it was fascinating that the people of Bangladesh have traded deaths from water-borne disease for long-term cancer risks, but I talked to an epidemiologist, Allan Smith at Berkeley, who figures it’s not worth arguing over which was worse. “For me, it’s not something I’ve ever cared to try to quantify. Clearly we want to reduce the deaths from gastroenteritis and clearly we want to reduce the deaths from arsenic. We should just move forward.”
Hey, so all those people weren’t lying: The Grand Canyon is spectacular. We only had time for a day trip between the concerts in Phoenix and Las Vegas, but I’m told we picked the prettiest trail to go down. It’s the South Kaibab Trail. It goes down into the canyon along a little ridge, so you get 360-degree views. Wow. It was pretty. And since it’s a canyon, the trail goes down fast. It starts out like this:
and goes on like this:
We stopped for lunch at the little bump just left of the middle of that picture, which also turned out to be a prime spot for knitting.
Yes, I (1) carried a partly-finished sweater 1.5 miles into the Grand Canyon and (2) was still wearing the wristband from the concert two days earlier. The sweater pattern is here, if you want to recreate the experience.
You have to be really careful hiking in the canyon, since this is the opposite of your normal hike – rather than going up (a mountain, say) in the morning and down in the afternoon, we went down and then had to get back up. But we adopted the motto “If you can perceive movement, you’re doing it wrong” and walked really, really, really slowly on the way out. We felt great, and the hike back up only took about 20 more minutes than the hike down. It made me think I could actually handle doing the whole canyon someday. I mean, some *two* days. I’m not crazy. The park is full of signs telling you not to do it in one day, many using this example.
We often wished we had a geologist along. For example, what the heck is going on here? This is in limestone at the top of the canyon (in that first set of switchbacks dropping down into the canyon).
Last week I reported on some strange rocks from South Australia that may preserve the oldest animal fossils. Or may not. Ok, nobody knows. But they look kind of like animals. Read about it here.