Here’s How The Body Keeps Time, Thanks to This Year’s Nobel Winning Science


Post 8537

Here’s How The Body Keeps Time, Thanks to This Year’s Nobel Winning Science

Image: RBerteig/Flickr

The human body is like a computer in a whole lot of ways. It’s got a processor, it’s got memory, it needs energy to run, it can solve problems, and, uh, it sees its fair share of porn. But it also has a clock—one whose mechanics have only been delved into fairly recently.

The Nobel Assembly at Karolinska Institutet awarded this year’s Nobel Prize in Physiology or Medicine to Americans Jeffrey C. Hall, Michael Rosbash and Michael W. Young “for their discoveries of molecular mechanisms controlling the circadian rhythm.” Thanks to some tinkering and peering into the ubiquitous Drosophila melanogaster fruit fly’s genetics, they figured out some of the genes and proteins responsible for making your clock tick.

We now know a lot more about the circadian rhythm, and subsequent scientists have expanded the research, finding similar proteins in humans (though there’s still a lot of work to do). Plenty of other scientists have now entered this field. But the work of these three laureates set the stage for all of that, by deconstructing and putting back together the tiny gears of the biological clock

Here’s how they did it.

The early 1980s was a much different time for DNA research—there was no human genome project, no CRISPR, and the computers used to evaluate DNA research were a lot slower. Science was slower in general. The papers were easier to read.

Image: NobelPrize.org

Scientists knew a whole lot about biological rhythms back then, but “almost nothing was known” about the molecular mechanisms behind it, according to one 1984 paper in Cell. But even earlier in the 1970s, a different team of researchers realized that a sequence of DNA called the period gene could be mutated to throw the fruit fly’s clock out of whack, with consequences including altering the way the flies moved around and the sound of their mating call. Robash and Hall were able to fix the mutated flies and restore normalcy to their circadian rhythm in that 1984 paper. Young and his team were able to isolate the thousands of base pairs (the letters that make up the words of the DNA instruction manual) responsible for this gene.

Once the researchers had isolated the gene, they had to figure out the actual proteins that did the work. DNA, after all, is just the instruction and not the worker actually carrying them out. Another kind of genetic material called RNA needs to translate the DNA, which is read elsewhere in the cell to create the proteins. Robash, Hall and their team’s further work showed that the amounts of RNA in the fly cells seemed to fluctuate based on the time and amount of light the flies were exposed to. Since RNA codes for proteins, that meant that some corresponding protein called PER would fluctuate over time as well, and could have some importance over the circadian rhythm. More importantly, this meant there must have been some internal feedback loop responsible for the clock. Your life has lots of feedback loops, like how you wait to answer your emails until there are too many, you freak out and check or delete everything, then let them pile up and the cycle continues.

But the scientists still needed to figure out why PER was changing cyclically—it was as if they had an inbox full of emails (the proteins) sent from the period gene, but no one to check and respond to them and no employer’s time clock to regulate the checking. Young and his team later discovered that another protein that they called timeless was the email checker, binding to PER so, after it built up too much, it could flood the nucleus and shut off the period gene. Another paper introduced doubletime, the protein that delays the timing so the timeless protein can clear the PER build up at, well, the right time.

The work of these three earned the three the Nobel Prize, although the field is still full of scientists trying to further understand the intricacies of the circadian rhythm.

The prizes will continue tomorrow with the Physics Prize, and Wednesday with the Chemistry Prize.

[Cell, Nature, Science, Cell, NobelPrize.org]

Advertisements

Why Has Our Sun Been Freaking Out So Much Lately?


Post 8536

Why Has Our Sun Been Freaking Out So Much Lately?

The solar flare as seen by NASA’s Solar Dynamics Observatory on September 10, 2017. (Image: NASA/SDO/Goddard)

Since early last week, the Sun has belched out a steady stream of solar flares, including the most powerful burst recorded in the star’s current 11-year cycle. It sounds very alarming, but scientists say this is simply what stars do every now and then, and that there’s nothing to be concerned about.

Solar flares are powerful bursts of radiation that stream out into space after periods of sunspot-associated magnetic activity. Sunspots are surface features that occasionally form owing to the strong magnetic field lines that come up from within the Sun and pierce through the solar surface. Solar flares are the largest explosive events in the Solar System, producing bright flashes that last anywhere from a few minutes to a few hours. Earth’s atmosphere protects us from most of their harmful rays, but this radiation can disturb GPS, radio, and communications signals, particularly near our planet’s polar regions.

The solar flare as seen by NASA’s Solar Dynamics Observatory on September 10, 2017. (Image: NASA/SDO/Goddard)

On Sunday September 10, 2017,NASA’s Solar Dynamics Observatory recorded an X8.2 class flare. Class X flares are the most intense flares, and the number attached to it denotes its strength, where X2 is twice as intense as X1, and X3 is three times as intense, and so on. M-class flares are a tenth the size of X-class flares and C-class flares are the weakest of the bunch. Both X- and M-class flares can cause brief radio blackouts on Earth, and other mild technological disruptions. Unless it’s part of an unusually strong solar storm—the kind that happens about once every one hundred years—in which case that would be very bad.

The latest flare spurted out from the Sun’s Active Region 2673, which scientists first noticed on August 29. Activity from this region began to intensify on September 4. Over the past week, NASA has catalogued six sizeable flares, including X2.2 and X9.3 flares on September 6, and an X1.3 flare on September 7. The X9.3 flare is the largest flare recorded so far in the current solar cycle—an approximately 11 year-cycle in which the Sun’s activity waxes and wanes. We’re in the ninth year of the current cycle, and we’re heading towards a solar minimum in terms of intensity. Flares like this are rare during this waning phase, but as these latest bursts show, they can still be pretty intense.

This gif shows both the X2.2 and the X9.3 flares that the Sun emitted on Sept. 6, 2017. (Image: NASA/GSFC/SDO)

“Big flares towards the end of sunspot cycles are not unusual, and in fact, that’s fairly standard behavior,” said Scott MacIntosh, director of the High Altitude Observatory at the National Center for Atmospheric research (NCAR), in an interview with Gizmodo. “The trick is to explain why.”

MacIntosh says that when the Sun’s activity gets low, the magnetic systems underlying the spots appear to be in close-contact near the equator. This creates an opportunity for the Sun to produce “hybrid” sunspots—regions which contain magnetic fields that twist like water in the Northern and Southern hemisphere oceans.

“Remember how the rotation of the Earth makes water [spin] in different directions in each hemisphere? The Sun does the same thing for the same reason—the Coriolis force,” said MacIntosh. “Those systems are veryunstable. Typically these types of spots produce the biggest, baddest flares and coronal mass ejections when they emerge through the Sun’s surface.”

But the paradoxical thing, says MacIntosh, is that the periods of very low solar activity are known to have produced the biggest geomagnetic storms in history, and these late-cycle events can persist for a very long time, even though the total number of flares is low. “It’s basically about how the different magnetic systems interact,” he says.

As a result of the most recent solar flares, NOAA’s Space Weather Prediction Center has issued a moderate geomagnetic storm watch for September 13, and a minor geomagnetic storm watch for September 14. This shouldn’t cause too much of a problem on Earth, but as NASA Solar Scientist Mitzi Adams explained to Gizmodo, we need to be concerned about flares and coronal mass ejections, since we’re now so reliant on technology that can be impacted by these events.

“The Space Weather Prediction Center (SWPC) shows an image from SOHO’s coronagraph with ‘speckles.’ The speckles are energetic charged particles interacting with the camera, which do degrade the camera over time,” said Adams. “These events also cause radio blackouts, corrosion in pipelines, and ground-induced currents that can damage transformers. Through monitoring and basic research, the goal is to understand what the Sun does and is likely to do so that we can prepare satellites, power grids, and even astronauts.”

The particles that speckle our cameras, says Adams, arrive about an hour after traveling about 93,000,000 miles per hour (150,000,000 km/h) from the Sun to the Earth. But the bulk of the particles take a couple of days to reach our planet, giving us some time to prepare.

Correction: A previous version of this post incorrectly identified the Space Weather Prediction Center as being run by NASA. Sorry about the error.

[NASA/Goddard, Space Weather Prediction Center]

An Earth-Sized Space Shield to Protect Us From Solar Storms Is Less Crazy Than It Sounds


Post 8535

An Earth-Sized Space Shield to Protect Us From Solar Storms Is Less Crazy Than It Sounds

 https://gizmodo.com/an-earth-sized-space-shield-to-protect-us-from-solar-st-1819057677
Image: NASA

Every 100 years or so, our Sun gives off a great big belch that sends an intense wave of charged particles towards Earth. This wasn’t a problem in the past, but our high-tech civilization is now disturbingly vulnerable to these solar storms. A new study quantifies the economic risks posed by these extreme solar storms, while also proposing a super-futuristic solution to the problem: an Earth-sized shield built in outer space.

The term “solar storm” is used to identify the various nasties the Sun can hurl our way, including x-rays, charged particles, and magnetized plasma. In 1859, a series of powerful coronal mass ejections (CMEs) hit our planet head on, disrupting telegraph stations and causing widespread communication outages.If we were to be hit by an equally powerful solar storm today, it would knock out satellites and electrical grids, disrupting global communications, transportation, and supply chains. Total worldwide losses could reach up to $10 trillion, with recovery taking many years.

We have no idea when the next Carrington-like event will occur, but a 2012 paper proposed a 10 percent chance of one happening in the next decade. Indeed, like an earthquake-prone city built above a pair of conflicting fault lines, it’s only a matter of time before our planet is hit by the next Big One. And to make matters worse, we’re becoming increasingly vulnerable to these events owing to steady technological advances.

A new paper by Manasvi Lingam and Avi Loeb from Harvard-Smithsonian Center for Astrophysics is the first to consider the economic impacts of a sizeable solar storm in the future, when our reliance on technology is far greater than it is today. In addition, the authors propose a strategy to mitigate the effects—and they’re not thinking small. Lingam and Loeb say we should construct a massive shield in space, and that the costs would be far lower than having to deal with the aftermath of a solar storm. The researchers go on to argue that advanced extraterrestrial civilizations have likely done this already, and that we should search for these shields as a way to detect aliens.

The new paper is currently being considered for publication in The Astrophysical Journal Letters.

To help them with their economic model, Lingam and Loeb factored in two important assumptions. First, the longer the duration between powerful solar flares, the more powerful they will be. Second, our civilization will experience exponential growths in technology and Gross Domestic Product (GDP) in the coming decades.

“We predict that within about 150 years, there will be an event that causes damage comparable to the current United States’ GDP of approximately $20 trillion, and the damage will increase exponentially at later times until technological development will saturate [i.e. when technological development finally starts to slow down and be globally distributed],” Loeb told Gizmodo. “Such a forecast was never attempted before.”

With these potentially catastrophic losses in mind, Lingam and Loeb turn to potential solutions. Unsurprisingly, the proposed mitigation strategies aren’t subtle, but of the three solutions considered, only one was deemed viable by the researchers.

“[Some] shielding solutions rely on placing physical object(s) between the Earth and the Sun. This would not work since the mass will be tremendous and can block the sunlight,” Lingam told Gizmodo. “Similarly, one can use electrical fields instead of magnetic fields. However, the problem is that the electrical field will repel positive particles but will attract the negative particles. Hence, we suggest that magnetic shielding is relatively the most viable.”

An illustration of the proposed magnetic deflector (not drawn to scale). (Image: Lingam and Loeb, 2017)

This Earth-sized “magnetic deflector” would be placed at the Lagrange L1 point between the Earth and the Sun at a distance of about 205,000 miles (329,000 km) from our planet’s surface. It would act as a current loop, and deflect the sun’s harmful particles back into space. The researchers say the required amount of deflective force is relatively small, and that we already have much of the technology required to make this possible. The big challenge, they say, will be to scale it up to its superstructural size.

“The related engineering project could take a few decades to construct in space,” said Loeb. “The cost for lifting the needed infrastructure to space (weighing 100,000 tons) will likely [cost around] hundreds of billions of dollars, much less than the expected [solar storm] damage over a century.”

The authors say the price of the magnetic deflector is comparable to the total cost of the International Space Station, and that it’s about three to four orders of magnitude cheaper than the current global GDP—or the economic damage from a flare in about a hundred years time. But that’s if we use material from Earth. It may make more economic sense to build the superstructure using materials extracted from the asteroid belt.

“I agree completely that the risk and economic damage from solar eruptions is too large and should be mitigated—imagine the current situation in Puerto Rico but worldwide,” said Anders Sandberg, a research fellow who works out of Oxford University’s Future of Humanity Institute, a part of the Oxford Martin School, in an interview with Gizmodo. “However, I was not convinced by their economic model at all… there seemed to be far too many arbitrary assumptions. In particular, the vulnerability of the world economy can both increase and decrease, for example, if we build a more modularized and resilient power grid.”

As for the prescribed solution—the magnetic deflector—Sandberg says it’s basically a “backup magnetic field,” and, as a megascale engineering problem, “not too daunting.”

“Just an Earth-sized loop of one-centimeter thick copper wire weighing 100,000 tons and presumably powered by a 1 TW solar power farm [should do it],” said Sandberg, who wasn’t involved in the new study. “It does not seem to be that far away from what we can currently do (except for that solar power farm). But it is not going to be as cheap as they calculated since the big cost is likely the energy system and installation, not the wiring. Now, reducing solar eruption risk is worth a lot, but I doubt this on its own will be cost-effective. As part of space industrialization, yes (especially since it is extra vulnerable), but otherwise I suspect smarter power-grids give more safety per dollar.”

Sandberg’s concerns notwithstanding, a gigantic magnetic deflector makes a lot of sense, particularly for a technological civilization considerably more advanced than our own. And in fact, it’s conceivable that some hypothetical alien civilizations have done this already. It would be wise, argue Loeb and Lingam, for us to search for signs of these shields as a way to detect extraterrestrial civilizations. We could do it using the transit method, the exoplanet detection technique that aims to observe such objects when they eclipse their host stars from our vantage point here on Earth.

“The [resulting] imprint could be changes in the brightness of the host star due to occultation (similar behavior to Tabby’s star) if the structure is big enough,” said Loeb. “The situation could be similar to Dyson spheres, but instead of harvesting the energy of the star [as a Dyson sphere hypothetically would], the purpose of the infrastructure is to protect a technological civilization on a planet from the flares of its host star.”

Andrew Siemion, Director of Berkeley SETI Research Center and Principal Investigator at the Breakthrough Listen program, says our deep dependence on electronics has created a particular susceptibility to stellar flare events, and that Loeb and Lingam have the right idea.

“Indeed we might some day attempt to mitigate these events using large scale ‘astroengineering,’ and under certain circumstances these structures could be detectable at interstellar distances,” Siemion told Gizmodo. “This is a fascinating thought experiment, and is exactly the kind of thinking that SETI scientists must continually engage in as we seek to identify technologies in the widest variety of incarnations.”

The authors of the new study are right to raise the prospect of solar storms as an important public issue. When it comes to mitigating existential or catastrophic natural hazards, our attention tends to be focused on asteroid impacts. Trouble is, solar storms happen with far greater frequency, so it would be a good idea to start thinking about mitigation strategies pretty much immediately. A solar deflector may be a sensible solution (eventually), but as Sandberg points out, it would also be smart to build a technological infrastructure that’s immune to the Sun’s harmful flares. The more angles we use to approach this problem, the better.

[A pre-print of this paper is available at arXiv]