For the first time in its history, the Doomsday Clock, an imaginary timepiece that represents humanity’s proximity to annihilation through mechanisms of our own design, has moved 30 seconds closer to calamity, with the minute hand now at 2 and a half minutes to midnight, the Bulletin of the Atomic Scientists announced this morning (Jan. 26).
The minute hand’s new position for 2017 was determined by the Bulletin’s Science and Security Board in consultation with a team of experts including 15 Nobel laureates. They last reset the clock on Jan. 22, 2015, at 3 minutes to midnight, with midnight representing global calamity.
Members of the Science and Security Board consider a number of factors when deciding which direction the clock will turn: nuclear threats, such as the total number of nuclear warheads in the world and the security of nuclear materials, as well as threats related to climate change, such as sea level rise and amounts of atmospheric carbon dioxide. They also consider the impacts of biosecurity and other emerging dangers, the Bulletin of the Atomic Scientists reported.
Facing multiple threats
Reviewing the events of 2016, experts found that expanding nuclear weapons development and ongoing testing in North Korea, India and Pakistan were causes for grave concern. Thomas Pickering, former U.S. undersecretary of state for political affairs (1997-2000) and U.S. ambassador to the United Nations, the Russian Federation, India, Israel, El Salvador, Nigeria and Jordan, told reporters that the contentious relationship between the U.S. and Russia was also troubling.
Despite the two countries being presently “at loggerheads with little prospect for negotiation,” Pickering said, he expressed hope that President Donald Trump and President Vladimir Putin might “take their now-budding relationship to something further and more meaningful in the area of nuclear arms reduction,” he said. [The Top 10 Ways to Destroy Planet Earth]
Government inaction in the face of climate change also played a part in the board’s decision to nudge the clock’s hands forward, according to David Titley, a professor of Practice in Meteorology at the Pennsylvania State University. Titley suggested that the new Trump administration should waste no time affirming its acceptance of incontrovertible scientific evidence that climate change is happening and that it is driven by human activity.
“There are no alternative facts that will make climate change magically go away,” Titley told reporters.
“The Trump administration has put forth candidates for cabinet-level positions that foreshadow the possibility that the new administration will be openly hostile toward even the most modest efforts to avert this catastrophic climate change,” Titley said. “Climate change should not be a partisan issue. The well-established physics of the Earth’s carbon cycle is neither liberal nor conservative in character,” he added.
Cybertechnology and biotechnology were also identified as emerging threats on a global scale, Lawrence Krauss, director of the Origins Project at Arizona State University, announced at the news conference.
Krauss also said that the purported recent intervention of Russia in the U.S. presidential campaign, as reported by U.S. intelligence agencies, highlights the vulnerability of critical information systems in cyberspace and undermines the workings of democracy. Across the world, increased reliance of governments, companies and individuals on the internet raises concerns about the impacts of sophisticated hacking on financial activities, nuclear power grids, power plants and personal freedoms, he said.
And while the development of DNA-editing technology — such as the one called clustered regularly interspaced short palindromic repeats (CRISPR) — offers new hope for disease cures, it also carries the risk of fueling malicious activities, as the techniques become more widely available, Krauss said.
With tech innovation happening so quickly, the input of scientific institutions and experts will be critical for global leaders to confront and manage new and complex threats, he said.
“The Clock ticks”
The Doomsday Clock was created in 1947 as a cover illustration for the Bulletin of the Atomic Scientists, a journal founded in 1945 by researchers who worked on the Manhattan Project, and who “could not remain aloof to the consequences of their work,” according to a mission statement. Intended as a warning about how little time there was for humanity to deal with the consequences of having nuclear weapons, its position was fixed at 11:53 p.m.
Since then, the Doomsday Clock has become a symbol of the ongoing peril posed by not only nuclear weapons but also climate change. Scientists and other experts on the Science and Security Board convene twice annually to assess the scope and scale of deadly global dangers and decide if the clock needs to be reset. The minute hand has ticked forward and back, changing position 22 times in the past 70 years.
It hovered as close as 2 minutes to midnight in 1953, when the U.S. and the Soviet Union tested their first thermonuclear weapons scarcely six months apart, and drifted as far as 17 minutes before the hour in 1991, with the end of the Cold War and the signing of a treaty between the U.S. and the Soviet Union promising a significant reduction of nuclear arsenals.
Closer to midnight
The Doomsday Clock’s minute hand didn’t move at all in 2016, but swept forward in 2015 — advancing from 5 minutes to 3 minutes before midnight — due to “unchecked climate change, global nuclear weapons modernizations, and outsized nuclear weapons arsenals,” all of which “pose extraordinary and undeniable threats to the continued existence of humanity,” the Science and Security Board reported.
The failure of world leaders to act on these threats escalated the probability of catastrophe on a global scale, and “the actions needed to reduce the risks of disaster must be taken very soon,” the board cautioned.
Though the Doomsday Clock is just a metaphor, the current deadly risk to humanity and the planet is all too real, according to the Bulletin. Now more than ever, our future hinges on global leaders who can confront and address the twin threats of climate change and nuclear weaponry, and work together to arrive at solutions that mitigate the peril to us all.
As the Science and Security Board warned in 2015, “The Clock ticks. Global danger looms. Wise leaders should act — immediately.”
The Earth’s magnetic field surrounds our planet like an invisible force field – protecting life from harmful solar radiation by deflecting charged particles away. Far from being constant, this field is continuously changing. Indeed, our planet’s history includes at least several hundred global magnetic reversals, where north and south magnetic poles swap places. So when’s the next one happening and how will it affect life on Earth?
During a reversal the magnetic field won’t be zero, but will assume a weaker and more complex form. It may fall to 10 percent of the present-day strength and have magnetic poles at the equator or even the simultaneous existence of multiple “north” and “south” magnetic poles.
Geomagnetic reversals occur a few times every million years on average. However, the interval between reversals is very irregular and can range up to tens of millions of years.
There can also be temporary and incomplete reversals, known as events and excursions, in which the magnetic poles move away from the geographic poles – perhaps even crossing the equator – before returning back to their original locations. The last full reversal, the Brunhes-Matuyama, occurred around 780,000 years ago. A temporary reversal, the Laschamp event, occurred around 41,000 years ago. It lasted less than 1,000 years with the actual change of polarity lasting around 250 years.
Power cut or mass extinction?
The alteration in the magnetic field during a reversal will weaken its shielding effect, allowing heightened levels of radiation on and above the Earth’s surface. Were this to happen today, the increase in charged particles reaching the Earth would result in increased risks for satellites, aviation, and ground-based electrical infrastructure. Geomagnetic storms, driven by the interaction of anomalously large eruptions of solar energy with our magnetic field, give us a foretaste of what we can expect with a weakened magnetic shield.
In 2003, the so-called Halloween storm caused local electricity-grid blackouts in Sweden, required the rerouting of flights to avoid communication blackout and radiation risk, and disrupted satellites and communication systems. But this storm was minor in comparison with other storms of the recent past, such as the 1859 Carrington event, which caused aurorae as far south as the Caribbean.
The impact of a major storm on today’s electronic infrastructure is not fully known. Of course any time spent without electricity, heating, air conditioning, GPS or internet would have a major impact; widespread blackouts could result in economic disruption measuring in tens of billions of dollars a day.
In terms of life on Earth and the direct impact of a reversal on our species we cannot definitively predict what will happen as modern humans did not exist at the time of the last full reversal. Several studies have tried to link past reversals with mass extinctions – suggesting some reversals and episodes of extended volcanism could be driven by a common cause. However, there is no evidence of any impending cataclysmic volcanism and so we would only likely have to contend with the electromagnetic impact if the field does reverse relatively soon.
We do know that many animal species have some form ofmagnetoreception that enables them to sense the Earth’s magnetic field. They may use this to assist in long-distance navigation during migration. But it is unclear what impact a reversal might have on such species. What is clear is that early humans did manage to live through the Laschamp event and life itself has survived the hundreds of full reversals evidenced in the geologic record.
Can we predict geomagnetic reversals?
The simple fact that we are “overdue” for a full reversal and the fact that the Earth’s field is currently decreasing at a rate of 5 percent per century,has led to suggestions that the field may reverse within the next 2,000 years. But pinning down an exact date – at least for now – will be difficult.
The Earth’s magnetic field is generated within the liquid core of our planet, by the slow churning of molten iron. Like the atmosphere and oceans, the way in which it moves is governed by the laws of physics. We should therefore be able to predict the “weather of the core” by tracking this movement, just like we can predict real weather by looking at the atmosphere and ocean. A reversal can then be likened to a particular type of storm in the core, where the dynamics – and magnetic field – go haywire (at least for a short while), before settling down again.
The difficulties of predicting the weather beyond a few days are widely known, despite us living within and directly observing the atmosphere. Yet predicting the Earth’s core is a far more difficult prospect, principally because it is buried beneath 3,000 km of rock such that our observations are scant and indirect. However, we are not completely blind: we know the major composition of the material inside the core and that it is liquid. A global network of ground-based observatories and orbiting satellites also measure how the magnetic field is changing, which gives us insight into how the liquid core is moving.
The recent discovery of a jet-stream within the core highlights our evolving ingenuity and increasing ability to measure and infer the dynamics of the core. Coupled with numerical simulations and laboratory experiments to study the fluid dynamics of the planet’s interior, our understanding is developing at a rapid rate. The prospect of being able to forecast the Earth’s core is perhaps not too far out of reach.
Welcome back to Giz Asks, a series where we ask experts hard questions about science, technology, and humanity’s future. Today, we’re wondering about the “speed of dark,” and for that matter, the scientific nature of “speed” and “darkness.”
The speed of light is one of the most important constants in physics. First measured by Danish astronomer Olaus Roemer in 1676, it was Albert Einstein who realized that light sets an ultimate speed limit for our universe, of 186,000 rip-roaring miles per second. But while the immutability of lightspeed is drilled into physics students at a young age, Einstein’s laws also state that all motion is relative, which got us thinking: what’s the speed of light’s nefarious doppleganger, darkness?
We’re not the first to ask this question (shout out comedian Steven Wright) or take it seriously, but in asking scientists and researchers, we left the interpretation of “darkness” open, eliciting some fascinating responses from experts on black holes and quantum physics. It turns out, darkness could be just as fast as light, or it could be infinitely slower—it all depends on your perspective.
The speed of dark? The easy answer is that it’s just the speed of light. Switch off the sun and our sky would go dark eight minutes later. But easy is boring! For starters, what we commonly call the “speed of light” is the speed of propagation, and that’s not always the deciding factor. A shadow swoops across the landscape at a speed governed by the object that casts it. For instance, as a lighthouse beacon rotates, it lights up the surroundings at regular intervals. The ground speed of its shadow increases with distance from the lighthouse.
While we’re at it, is there even such a thing as darkness? If you did switch off the sun, Earth wouldn’t go completely dark. Light from stars, nebulae, and the big bang would fill the sky. The planet and everything on it, including our bodies, would blaze in the infrared. Depending on how, exactly, you’d managed to switch the sun off, it would keep on glowing for eons. As long as we were able to see, we’d see something. No light detector can register total darkness, because, if nothing else, quantum fluctuations produce tiny flashes of light. Even a black hole, the darkest conceivable object, emits some light. In physics, unlike human affairs, light always chases away dark.
Darkness isn’t a physical category, but a state of mind. Photons hitting, or not hitting, retinal cells may trigger the experience, but do not explain the subjective experience of darkness, any more than the length of waves explains the experience of color or sound. Our conscious experience changes from moment to moment, but the individual frames of that experience are timeless. In that sense, darkness has no speed.
And what about speed in general—is there such a thing? It presupposes a framework of space, and scientists see phenomena in quantum physics where spatial concepts seem not to apply—suggesting, to some, that space is derived from a more fundamental level of reality where these is no such as thing as position, distance, or speed. It must be the level that Steven Wright operates on.
Close to a black hole, matter falls in at a speed that is close to the speed of light. Once it enters the so-called event-horizon of the black holes, nothing can escape. Even light is trapped inside the horizon forever. Hence a black hole can be thought of as the ultimate prison.
A star like the Sun can be shredded (“spaghettified”) into a stream of gas if it passes too close to a massive black hole, like the one (weighting six billion solar masses) at the center of the Milky Way galaxy.
As matter falls into the black hole, it often rubs against itself and heats up. As a result it radiates. If the accretion rate is high enough, the force of the radiation flowing out could potentially stop additional matter from falling in. Many of the most massive black holes in the universe, weighting billions of solar masses, are observed to accrete at the maximum possible rate (also called the Eddington limit, after Sir Arthur Eddington who discovered theoretically the maximum radiation output possible for gravity to overcome the radiation force).
Neil DeGrasse Tyson
Director of the Hayden Planetarium at the Rose Center for Earth and Space, research associate and founder of the Department of Astrophysics at the American Museum of Natural History, host of Cosmos: A Spacetime Odyssey
The speed of dark… Consider dark getting erased by light. The light erases it at the speed of light so the speed of dark would be negative the speed of light. If light is a vector, it has magnitude and direction, so… to call it negative means it’s in a negative direction. The dark is receding rather than advancing. I’d call it negative the speed of light.
Postdoctoral Researcher at Leonard E. Parker Center for Gravitation, Cosmology & Astrophysics, University of Wisconsin-Milwaukee
A black hole has gravity so strong that not even light can escape once it has passed the event horizon, an invisible boundary marking the point of no return. Because the black hole has such strong gravity, time dilation will affect observations from outside the strong gravitational field.
For example, a distant observer watching a glowing object fall into a black hole will see it slow down and fade, eventually becoming so dim it cannot be seen. This observer won’t ever see the object cross the event horizon.
We can also take the perspective of stuff falling into the black hole, instead of a distant observer. For example, if we take a black hole in the center of a glowing gas cloud, say from a star that has been broken up by passing too close to the black hole, the material will form a flattened disk, known as an accretion disk. This gas will fall into the black hole, but it is not instantaneous. There is a speed limit enforced by the radiation pressure from the hot gas which will fight against the inward force of gravity from the black hole. As the gas falls into the black hole, the black hole grows in size. If a black hole that is 10 times as massive as our Sun is accreting at the maximum allowed rate, in about a billion years it could have reached 100 million times the mass of our Sun.
Executive Director of LIGO Laboratory at the California Institute of Technology
Basically, it depends on whether you’re the matter being consumed by the infinite abyss of a black hole or you’re far enough away to be a dispassionate observer watching someone else falling into the infinite abyss. If you happen to be the unlucky matter falling in, the speed is potentially very large, in principle approaching the speed of light.
If you’re the observer and you’re far enough away, the speed with which matter is consumed is dramatically slowed down due to an effect known as gravitational time dilation—clocks run slower in gravitational fields, and much slower in the immense gravitational fields near the event horizon of the black hole. By ‘far enough away’, I mean that in your local reference frame, your stationary relative to the black hole (i.e, not getting sucked in) and your local clock is not affected by the gravitational field of the black hole. In fact, to the far away person it will take an infinite amount of time for something to travel to the event horizon of the black hole.
Associate Professor of Astrophysics and Gravitation in the Department of Physics and Astronomy at the University of Waterloo, Associate Faculty of Cosmology and Gravitation at the Perimeter Institute for Theoretical Physic (PI)
I believe the speed “of dark” is infinite! In classical physics, the vast darkness of space could be just empty vacuum. However, we have learnt from quantum mechanics that there is no real dark or empty space. Even where there is no light that we can see, electromagnetic field can fluctuate in and out of existence, especially on small scales and short times. Even gravitational waves, the ripples in the geometry of spacetime that were recently observed by the LIGO observatory, should have these quantum fluctuations.
The problem is that the gravity of these quantum ripples is infinite. In other words, currently there is no sensible theory of quantum gravity that people could agree on. One way to avoid the problem is if the speed “of dark”, i.e. the quantum ripples, goes to infinity (or becomes arbitrarily big) on small scales and short times. Of course, that’s only one possibility, but is a simple (and my favourite) way to understand big bang, black holes, dark energy, and quantum gravity.
Amazing Images: The Best Science Photos of the Week
By Livescience.com, staff | January 21, 2017 09:14am ET
Each week we find the most interesting and informative articles we can and along the way we uncover amazing and cool images. Here you’ll discover 10 incredible photos and the stories behind them.
The most comprehensive review of primate populations ever conducted finds that 60 percent of our closest biological relatives are threatened with extinction.
A shadowy turtle twice the size of Earth swims across the sun in new images from the ALMA radio telescope in Chile, viewing the sun for the first time and documenting the area right above its visible surface.
No, the space-based Solar Dynamics Observatory isn’t on the fritz—it was actually instructed to make this flip while snapping pics of the Sun. It might sound like NASA took this thing out for a joy ride, but there’s a very good reason for the evasive maneuver.
Since 2010, the SDO has been dutifully studying the sun, sending back some of the most stunning pictures we’ve ever seen of this flaming orb. Twice each year, NASA has the SDO perform a complete 360, and it does this to the help the probe’s Helioseismic and Magnetic Imager (HMI) instrument take precise measurements of the outer edge of the sun, known as the “solar limb,” as seen by the SDO.
Taking measurements with the HMI instrument is not without its challenges. The sun, with all its flares and stellar perturbations, is not a totally spherical object. This makes it tough for HMI to detect the sun’s outer perimeter when it’s perfectly still. The probe’s biannual spin allows each part of the camera to peer at the entire outer rim, allowing it to map the sun’s shape with greater accuracy.
The video shown above was taken in extreme ultraviolet wavelengths, a spectrum of light our eyes cannot detect. NASA colorized these wavelengths in gold, allowing us puny humans to view it. As the SDO performed its seven-hour maneuver, it took a photo once every 12 seconds. The resulting video makes it look the sun suddenly decided to perform a rather dramatic summersault.
New up-close-and-personal shots from the Atacama Large Millimeter/Submillimeter Array (ALMA) in Chile reveal a very large sunspot that looks remarkably like the Eye of Sauron. According to the European Southern Observatory (ESO), ALMA used radio interferometry to create the images, meaning it used antennas to receive radio waves from the Sun.
Sunspots are oases of (relative) coolness on the Sun’s visible surface, called the photosphere. While sunspots are often pretty large, this one captured by ALMA could fit roughly two Earths in it. It’s a monster.
It’s also rather pretty, in a chaotic way.
The ESO is particularly interested in using ALMA to study the layer above the sun’s photosphere, called the chromosphere. “The images reveal differences in temperature between parts of the Sun’s chromosphere,” the ESO said in apress release. “Understanding the heating and dynamics of the chromosphere are key areas of research that will be addressed in the future using ALMA.”
Sure, the Sun looks like the bottom of a Doritos bag. But it’s literally why we’re here, so show some respect.