University of Tokyo scientists observe predicted quantum biochemical effects on cells.
Radical pairs<p>The phenomenon observed by scientists from the University of Tokyo matched the predictions of a theory put forward in 1975 by <a href="https://www.discovermagazine.com/planet-earth/how-birds-see-magnetic-fields-an-interview-with-klaus-schulten" target="_blank">Klaus Schulten</a> of the Max Planck Institute. Schulten proposed the mechanism through which even a very weak magnetic field—such as our planet's—could influence chemical reactions in their cells, allowing birds to perceive magnetic lines and navigate as they seem to do.</p><p>Shulten's idea had to do with radical pairs. A radical is a molecule with an odd number of electrons. When two such electrons belonging to different molecules become entangled, they form a radical pair. Since there's no physical connection between the electrons, their short-lived relationship belongs in the realm of quantum mechanics.</p><p>Brief as their association is, it's long enough to affect their molecules' chemical reactions. The entangled electrons can either spin exactly in sync with each other, or exactly opposite each other. In the former case, chemical reactions are slow. In the latter case, they're faster.</p><img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8yNTQzNDcxNi9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTYzNzMxNDc0N30.fvjXhn5uNKgbISXfMjj9J6-PIs0EgwqXA1X0PTPa7cc/img.jpg?width=980" id="52415" class="rm-shortcode" data-rm-shortcode-id="d675ae83cf35b04342cd7d75b65ba0b0" data-rm-shortcode-name="rebelmouse-image" data-width="1234" data-height="1440" />
Researchers Jonathan Woodward and Noboru Ikeya in their lab
Credit: © Xu Tao, CC BY-SA
Cryptochromes and flavins<p>Previous research has revealed that certain animal cells contain <a href="https://en.wikipedia.org/wiki/Cryptochrome" target="_blank">cryptochromes</a>, proteins that are sensitive to magnetic fields. There is a subset of these called "<a href="https://en.wikipedia.org/wiki/Flavin_group" target="_blank">flavins</a>," molecules that glow, or autofluoresce, when exposed to blue light. The researchers worked with human HeLa cells (human cervical cancer cells), because they're rich in flavins. That makes them of special interest because it appears that geomagnetic navigation is <a href="https://jeb.biologists.org/content/204/19/3295" target="_blank">light-sensitive</a>.</p><p>When hit with blue light, flavins either glow or produce radical pairs — what happens is a balancing act in which the slower the spin of the pairs, the fewer molecules are unoccupied and available to fluoresce.</p><img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8yNTQzNDcyMC9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTY3MTIxMTkyNX0.jkJMYwj6Sbpmy6Lj4vLIc6IMXSLoBDeDC6ixhTdn-Ro/img.jpg?width=980" id="8f1c0" class="rm-shortcode" data-rm-shortcode-id="8b639aedfc9b1a5f3a77159fe1ab7d82" data-rm-shortcode-name="rebelmouse-image" data-width="1200" data-height="402" />
HeLa cells (left), showing fluorescence caused by blue light (center), closeup of fluorescence (right)
The experiment<p>For the experiment, the HeLa cells were irradiated with blue light for about 40 seconds, causing them to fluoresce. The researchers' expectations were that this fluorescent light resulted in the generation of radical pairs.</p><p>Since magnetism can affect the spin of electrons, every four seconds the scientists swept a magnet over the cells. They observed that their fluorescence dimmed by about 3.5 percen each time they did this, as shown in the image at the beginning of this article.</p><p>Their interpretation is that the presence of the magnet caused the electrons in the radical pairs to align, slowing down chemical reactions in the cell so that there were fewer molecules available for producing fluorescence.</p><p>The short version: The magnet caused a quantum change in the radical pairs that suppressed the flavin's ability to fluoresce.</p><p>The University of Tokyo's <a href="http://gpes.c.u-tokyo.ac.jp/faculty-staff/measurement-and-evaluation/jonathan-r-woodward.html" target="_blank">Jonathan Woodward</a>, who authored the study with doctoral student Noboru Ikeya, <a href="https://www.u-tokyo.ac.jp/focus/en/press/z0508_00158.html" target="_blank" rel="noopener noreferrer">explains</a> what's so exciting about the experiment:</p><p style="margin-left: 20px;">"The joyous thing about this research is to see that the relationship between the spins of two individual electrons can have a major effect on biology."</p><p>He notes, "We've not modified or added anything to these cells. We think we have extremely strong evidence that we've observed a purely quantum mechanical process affecting chemical activity at the cellular level."</p>
New research sees dogs checking a North-South axis on their way home.
- As dogs navigate, they appear to be using the Earth's magnetic fields.
- 170 dogs orient themselves to north and south as they plot shortcuts back to their people.
- Dogs join the growing number of magnetism-sensitive animals.
Guessing the secrets of canine navigators<p>That dogs have excellent navigational talents is nothing new. The study recalls "messenger dogs" that were relied on during World War I to ferry sensitive communiqués back and forth across battle lines. In addition, of course, hunting dogs, or "scent hounds," have long exhibited the ability to return to their owners' positions, and previous studies have shown that they often devise new return routes, as opposed to simply retracing their steps. How they do this has been a bit mysterious, as the study notes: "Dogs often homed using novel routes and/or shortcuts, ruling out route reversal strategies, and making olfactory tracking and visual piloting unlikely."</p><p>In trying to figure out how dogs do what they do, researchers have divided their methods into three possible modes:</p><ul><li>tracking — following their own scent trail back to their point of origin</li><li>scouting — searching for a new, shorter way back to their point of origin</li><li>visual piloting — using landmarks to find their way back</li></ul><p>Benediktová's research began when she put video cameras and GPS trackers on four dogs, took them out into the forest, and set them loose. As might be expected, they took off in pursuit of some interesting scent. All of the dogs eventually returned. She mapped the collected GPS data, seeing runs of both tracking and scouting.</p><p>However, when she showed her maps to Burda, he noticed something else. Just before scouting their way back, the dogs did something odd: They ran for roughly 20 meters along a precise north-south axis, as if orienting themselves, before returning to Benediktová. Without some form of magnetic sensitivity, this would not be possible.<br></p><img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8yMzUwMjY4OC9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTYzNjg2MDkyNX0.IxUIornhkTGk8aOxMclbByDmKW82FO4O6nXJ9-4Vpko/img.jpg?width=980" id="93a31" class="rm-shortcode" data-rm-shortcode-id="54d17432f595df655c0b8a8afe084956" data-rm-shortcode-name="rebelmouse-image" data-width="1500" data-height="1444" />
Image source: Benediktová, et al
Testing the theory<p>A sample of four dogs is hardly definitive, so student and advisor developed a larger study involving 27 dogs who were taken on several hundred scouting trips over the course of three years. The dogs were typically taken to locales with which they had no familiarity, and the researchers avoided tipping off the canines with any navigational clues including the avoidance of situations in which wind could carry their scent toward the dogs. The researchers also hid after releasing their charges to make sure they weren't visible to the pooches.</p><p>In the end, the researchers documented 223 scouting runs in which the dogs averaged a return to their points of origin of about 1.1 kilometers (around 0.7 miles).</p><p>In 170 of these runs, the dogs did indeed repeat the smaller sample's behavior, running about 20 meters along a north-south axis. Just as intriguingly, it was these dogs who found the fastest, most direct route back. "I'm really quite impressed with the data," biologist Catherine Lohmann of the University of North Carolina, Chapel Hill, who was not involved in the study, tells <a href="https://www.sciencemag.org/news/2020/07/dogs-may-use-earth-s-magnetic-field-take-shortcuts" target="_blank">Science</a>.</p><p>Burda considers the dogs' seeming reliance on their north-south jog to be pretty convincing: "It's the most plausible explanation."</p> <div class="rm-shortcode" data-media_id="1W7raq4T" data-player_id="FvQKszTI" data-rm-shortcode-id="f1f23d529719339a12114da473a619ca"> <div id="botr_1W7raq4T_FvQKszTI_div" class="jwplayer-media" data-jwplayer-video-src="https://content.jwplatform.com/players/1W7raq4T-FvQKszTI.js"> <img src="https://cdn.jwplayer.com/thumbs/1W7raq4T-1920.jpg" class="jwplayer-media-preview" /> </div> <script src="https://content.jwplatform.com/players/1W7raq4T-FvQKszTI.js"></script> </div>
Proving the theory<p>Commenting on the research, dog behaviorist Adam Miklósi at Eötvös Loránd University tells Science, "The problem is that in order to 100% prove the magnetic sense, or any sense, you have to exclude all the others."</p><p>Given the difficulties of doing that, Benediktová and Burda intend to test their hypothesis from the other direction, seeing if they can confuse dogs' magnetnoreception by placing magnets on their collars and repeating the tests — if they no longer do their little north-south jog, a reliance on the Earth's magnetic field would look even more likely. </p>
You won't notice much of a difference unless you're north of the 55th parallel, though.
- Magnetic north has recently been moving north from Canada to Russia in a cold hurry.
- It's moving about 33 miles a year instead of the usual 7 miles.
- World navigation models had to updated ahead of schedule to catch up with it.
North, north, and north<img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8xOTE2MjQ5MC9vcmlnaW4uZ2lmIiwiZXhwaXJlc19hdCI6MTYzODEwOTk0N30.SD7sUcv5s1GoxAng0TTdtfhT-5xV2K_2pXHsS9BxtYU/img.gif?width=980" id="12c8a" class="rm-shortcode" data-rm-shortcode-id="bd173f5f3a2619d67820e11a25dcc248" data-rm-shortcode-name="rebelmouse-image" />
Image source: Pyty / Shutterstock<p>There are actually three flavors of north, and they're all in different places.</p> <ul> <li><em>Magnetic north</em> — is defined as the location on the Earth's surface where all of its magnetic lines point straight downward. If you look at a compass while you're there, the needle attempts to dip down; that's why it's also called the "dip pole." Magnetic north is always on the move in response to the constant motion of electrical charges in the Earth's liquid outer mantle, which produces Earth's magnetic field.<span></span></li></ul><ul><li><em>Geomagnetic north</em> — is the northern focus of the Earth's magnetosphere, up in the stratosphere. It moves, too, but not nearly as much, since shifts in the Earth's magnetic field are more smoothed-out up there than on the ground. Its location is pretty stable, <a href="http://wdc.kugi.kyoto-u.ac.jp/poles/polesexp.html" target="_blank" data-vivaldi-spatnav-clickable="1">located</a> above and off the northwest coast of Greenland.<span></span></li></ul><ul> <li><em>True north</em>, or <em>geographic north</em> — is the northern terminus of our lines of longitude. It's located in the middle of the Arctic Ocean.</li> </ul>
What’s the hurry?<img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8xOTE2MjUzMC9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTYxOTEyMjgwNn0.kzhzoWnDITtIG0u_h-gx_8x6dVNMPpjPMmIvx3-YQQ0/img.jpg?width=980" id="dea99" class="rm-shortcode" data-rm-shortcode-id="a1eee701aef6ee6142209f89593e0273" data-rm-shortcode-name="rebelmouse-image" />
Image source: Johan Swanepoel / Shutterstock<p>The suddenly accelerating movement of magnetic north has scientists wondering what's up — not because there's any danger we're aware of — because its behavior is one of the few opportunities they have to catch a glimpse of the dynamics inside the earth's molten outer core.</p><p>The most prominent theory is that the speed-up is being driven by, as <a href="https://www.nature.com/articles/d41586-019-00007-1" target="_blank" data-vivaldi-spatnav-clickable="1"><em>Nature</em></a> puts it, "liquid iron sloshing within the planet's core." Giant streams of molten iron and nickel continually twist and swirl in the outer core, a pressure cooker that can reach 9,000° F in temperature. The iron is the source of the magnetic fields that comprise the Earth's magnetosphere. The magnetosphere is the barrier that keeps us protected from destructive ultraviolet solar radiation — its existence keeps Earth habitable. Planets with no magnetic barrier are unable to hold onto their atmosphere. Mars lost its magnetosphere 4.2 billion years ago. </p><p>Geophysicist <a href="https://environment.leeds.ac.uk/see/staff/1381/dr-phil-livermore" target="_blank" data-vivaldi-spatnav-clickable="1">Phil Livermore</a> made the case at an <a href="https://fallmeeting.agu.org/2018/" target="_blank" data-vivaldi-spatnav-clickable="1">American Geophysical Union meeting</a> in Fall 2018 that what we're seeing is the latest action in an ongoing tug of war between two magnetic fields down in the swirling outer core. One is under Siberia, and one is under Canada. Historically, the Canadian field has been winning, keeping magnetic north in Canada. However, there's been a shift, he tells <a href="https://www.nationalgeographic.com/science/2019/02/magnetic-north-update-navigation-maps/" target="_blank" data-vivaldi-spatnav-clickable="1"><em>National Geographic</em></a>, "The Siberian patch looks like it's winning the battle. It's sort of pulling the magnetic field all the way across to its side of the geographic pole."</p><p>Some scientists think that the acceleration may be an early sign that Earth's magnetic poles are about to flip, something that happens every every 200,000 to 300,000 years. Others see no evidence of that. Plus, flips occur over thousands of years, so there'd be no cause for alarm anyway.</p>