Paul Loosen, Staff Writer, Physicist discussed on Science Magazine Podcast
Now he has staff writer Paul Loosen. He wrote a story this week on a quantum diamond microscope. That can look at fine traces of magnetism. Hi Paul Blow what. I say find traces of magnetism mean how fine. How small are these little pieces of banditism? These are magnetic signals trapped in ancient ancient rocks typically that get down to grains of the rock that are thinner than the width of a human hair. How does it work? I used the word diamond and the word quantum and iker scope which. I'm not exactly sure how they all relate to each other is actually kind of complicated. But we're here boils down pretty easily so diamonds in their carbon lattice view injected nitrogen atom into it knocks out one of the carbons and the next to it. This vacancy to call the nitrogen vacancy center that little vacancy has low cloud of electrons around act like free atoms. That are very hyper sensitive to magnetic fields among other things. And so if you stick the diamond right next to that sample you're trying to get at then. Stimulate it with laser light a sign of the magnetism of that sample POPs right up and sign is glowing Yeah it's Changes in the color red. This was something that was observed when people were looking at diamonds as components of quantum computing. Yeah I mean. People have known about these imperfections for decades and physicist used it for a long time to experiment on quantum stuff you know it's existent room temperature solid piece of matter and then some physicists at Harvard and elsewhere realized. Hey you know this could actually be a super sensitive sensor for applications and not just are playing around. Yeah we about this as something that can kind of do spatial resolution of magnetism in rocks Is it more sensitive then instruments and if so how sensitive is it? It is not the most sensitive. It's very sensitive but there are these cryogenically cooled. Superconducting Squid. Magnetometers are called are much more sensitive. Still they're trying to get it up to that sensitivity. But they've wasted on that so really you know it's something that can do a lot of samples but it's this resolution where it can get finer details and show you the overall map for lines up with the microscopic picture you have of what you're looking at what. I caught my attention about. This topic was actually a science advances paper. That's also coming out this week on very early plate tectonics and actually lead the quantum diamond microscope fit into this. Finding and then it turns out you know has had a lot of other interesting results using this technique. So can you talk to us first about the early plate? Tectonics so this is dame back three point two billion years ago okay. That seems really early. It's within the range of what many geologists expect. There's a huge error bar anytime from three billion years ago to four plus billion years ago soon after Earth formed there are credible guesses that could be made their different lines of evidence but this type of Paleo magnetism evidence which is very good evidence hadn't previously been found past two point eight billion years ago. So how can Paleo magnetism tell us about tectonic movement the Earth's magnetic field Runs to these rocks as their crystallizing spins the electrons around and causes orientation in the magnetic rocks. And that is than fossilized into the rock as it turns from lava into assault both spent decades figuring out how to extract these signals. Back out of these lavas not just with this curium but also with these super sensitive other times. Superconducting sensors see. You can see how the rocks were oriented when they solidified and then if the plates move you can say oh well. This one's not where we expected to be right. So you have this one data point and then if you have another one for three point five billion years ago for nearby rocks you can be like. Hey this is the minimum distance. They must have traveled. How is this different? From other techniques that have examined Paleo magnetism that have been applied to this problem? There some break techniques out there. You know the new study you mentioned uses those as well to get the actual estimate of the pill magnetism because that's still a more sensitive technique with acuity M does is it allows you to believe your estimate because the the old estimates would give you this bulk signal and accused him. Gives you kind of a map of this tiny thing where you can say oh? Is this magnetic field coming? From something that formed right the rock formed or is it something that happened later on some sort of magnetism that can be imported law new magnetic. Graham's come in ob it's all some distortion trying to figure out what's primary versus. Secondary fuels allow debate in the field. What would it mean if we could pin down a date for when plate tectonic started? Why's that important I? It's kind of just goes back to our basic understanding of how the world works. We know it started right. But what are the world. Look like before if you go far back enough. It can come into the debates about the rise of life. Was Plato conches. Involved in the rise of life did it fuel the carbon cycle the kind of hardcore massive skill rock carbon cycle. It all depends on how far back you push it. But these kind of connections to the evolution of life on earth changes in kind of chemistry of Earth. All can get skewed. Depending on one plate to Connex started this has been used on rocks from Outer Space. Or are they trying to learn by looking at the magnetic map of this meteorite? Will they know it? Likely formed around present-day Jupiter further out than previously measured meteorite for magnetism. And with the kind of fine spatial scale. They could see this one little sulfide ram of this little melt inclusion that could have you know a magnetic signature from the very early solar system and they saw a very weak magnetic field from it weaker than they might have expected to see compared to the previous data points they have of a meteorite that form closer to the center of the solar system. What's generating a magnetic field? In that scenario it comes from the first collapse of the molecular cloud to form the the dust disk and then sheer rotation in the dust convince amplify. What kind of questions are people asking about magnetic fields? At that time the traveling question here is to what extent exist but did it play a role in the formation of the planets so you can explain the formation of the without magnetism but it's quite possible that some also played a role in bringing together these dust particles to form into comes into your comps bigger clumps that eventually became plaza moles and then planets. And if you can especially if you can find that the magnetic field is patchy and variable not just this uniform thing then maybe these patches were stronger helped 'cause planet formation. You mentioned to me but it's not in a story another application for this for extra terrestrial rocks or non earth rocks. Yes so Roger Food. Who's the geologist? Who's been pushing? This forward has a a famous meteorite sane in his lab perhaps one of the most infamous meteorites in the world a meteorite from Mars that back in the nineties was blamed as evidence of life on Mars Life on Mars next not looking for life on ours. But it's also called one of the most studied rocks maybe the most state rock on the planet. He's searching for signs of the ancient Martian magnetic field from that and when it started how it might have changed very cool all right. Thank you so much Paul. My pleasure follow loose and is a staff writer for science. You can find a link to his story and a related paper in science advances on plate tectonics at science mag dot org slash podcast and that concludes this edition of the Science. Podcast if you have any.