Well, here we are two weeks into the era of gravitational wave astronomy. I trust that by now you have read and heard all about the LIGO discovery of gravitational waves from two black holes merging and what it means for astronomy.
These are indeed exciting times and it is worth pausing to think about this announcement in the context of other big astronomical discoveries that were generations in the making. Perhaps the best historical analog for the gravitational wave search and detection is the search for the trigonometric parallax, or a method to measure the distance to stars. Its existence was long theorized, but observational evidence was harder to come by. Read More
Many of the questions I am asked regard how “true” science fiction concerning black holes might be, and whether worm holes, such as those featured in Stargate, are real or not. Invariably though, the one item that is almost assured to come up are the largely gruesome ways in which black holes might theoretically affect human beings and the Earth itself.
There are three properties of a black hole that are (in principle) measurable: their mass, their spin (or angular momentum) and their overall electronic charge. Indeed, these are the only three parameters that an outside observer can ever know about since all other information about anything that goes into making up a black hole is lost. This is known as the “no hair theorem”. Put simply: no matter how hairy or complex an object you throw into a black hole, it will get reduced down (or shaved) to its mass, charge and spin.
Of these parameters, mass is arguably the most significant. The very definition of a black hole is that it has its mass concentrated in to a vanishingly small volume – the “singularity”. And it is the mass of the black hole – and the huge gravitational forces that its mass generates – which does the “damage” to nearby objects.
One of the best known effects of a nearby black hole has the imaginative title of “Spaghettification”. In brief, if you stray too close to a black hole, then you will stretch out, just like spaghetti.
This effect is caused due to a gravitation gradient across your body. Imagine that you are headed feet first towards a black hole. Since your feet are physically closer to the black hole, they will feel a stronger gravitation pull toward it than your head will. Worse than that, your arms, by virtue of the fact that they’re not at the center of your body, will be attracted in a slightly different (vector) direction than your head is. This will cause parts of the body toward the edges to be brought inward. The net result is not only an elongation of the body overall, but also a thinning out (or compression) in the middle. Hence, your body or any other object, such as Earth, will start to resemble spaghetti long before it hits the center of the black hole.
The exact point at which these forces become too much to bear will depend critically on the mass of a black hole. For an “ordinary” black hole that has been produced by the collapse of a high mass star, this could be several hundred kilometers away from the event horizon – the point beyond which no information can escape a black hole. Yet for a supermassive black hole, such as the one thought to reside at the center of our galaxy, an object could readily sink below the event horizon before becoming spaghetti, at a distance of many tens of thousands of kilometers from its center. For a distant observer outside the event horizon of the black hole, it would appear that we progressively slow down and then fade away over time.
What would happen, hypothetically, if a black hole appeared out of nowhere next to Earth? The same gravitational effects that produced spaghettification would start to take effect here. The edge of the Earth closest to the black hole would feel a much stronger force than the far side. As such, the doom of the entire planet would be at hand. We would be pulled apart.
Equally, we might not even notice if a truly supermassive black hole swallowed us below its event horizon as everything would appear as it once was, at least for a small period of time. In this case, it could be some time before disaster struck. But don’t lose too much sleep, we’d have to be unfortunate to “hit” a black hole in the first place – and we might live on holographically after the crunch anyway.
Interestingly, black holes are not necessarily black. Quasars – objects at the hearts of distant galaxies powered by black holes – are supremely bright. They can readily outshine the rest of their host galaxy combined. Such radiation is generated when the black hole is feasting on new material. To be clear: this material is still outside the event horizon which is why we can still see it. Below the event horizon is where nothing, not even light, can escape. As all the matter piles up from the feast, it will glow. It is this glow that is seen when observers look at quasars.
But this is a problem for anything orbiting (or near) a black hole, as it is very hot indeed. Long before we would be spaghettified, the sheer power of this radiation would fry us.
For those who have watched Christopher Nolan’s film Interstellar, the prospect of a planet orbiting around a black hole might be an appealing one. For life to thrive, there needs to be a source of energy or a temperature difference. And a black hole can be that source. There’s a catch, though. The black hole needs to have stopped feasting on any material – or it will be emitting too much radiation to support life on any neighboring worlds.
What life would look like on such a world (assuming its not too close to get spaghettified, of course) is another matter. The amount of power received by the planet would probably be tiny compared to what Earth receives from the Sun. And the overall environment of such a planet could be equally bizarre. Indeed, in the creation of Interstellar, Kip Thorne was consulted to ensure the accuracy of the depiction of the black hole featured. These factors do not preclude life, it just makes it a tough prospect and very hard to predict what forms it could take.
A flurry of newspaper headlines have called into question the existence of SAD, or Seasonal Affective Disorder. Scientists, they reported, appear to have debunked a widespread conviction, that feeling low in winter time is a genuine illness caused by disturbed levels of brain chemicals and that demands treatment.
A visit to any number of Seasonal Affective Disorder (SAD) websites leads to online questionnaires offering “diagnosis”, treatment recommendations, and advertisements for light boxes – gadgets that simulate daylight and compensate for poor exposure to the real thing. SAD is identified as a form of depression caused by disturbances of hormonal rhythms sensitive to daylight, primarily melatonin. Unusually, intense exposure to artificial light often is advocated as a treatment. There is even a device that can be worn on the head, allowing the patient to use a light box on the move. Read More
Last month, a flock of trumpeter swans alighted on the wetlands of the Malheur National Wildlife Refuge in Oregon, repeating an annual ritual that dates back centuries. But for the first time in 80 years, biologists were not there to count them.
The annual winter bird count, which dates back to 1935, provides key data on multiple species for a national migratory bird monitoring program. Biologists and volunteers count ibis, sandhill cranes, horned larks and other birds that stop at the refuge – an oasis in the high desert of the Great Basin.
But this year, the only people inside the refuge at the start of bird-counting season were a small group of armed militants. Instead of counting birds, refuge scientists are counting days. Monday marks the 38th day of the occupation, orchestrated by ranchers and others angered by a five-year prison sentence handed to local cattlemen Steven and Dwight Hammond for arson – and, more broadly, federal oversight of cattle grazing on public lands. Last week, 11 of the occupiers were arrested while traveling to a meeting, including the movement’s ringleader, Ammon Bundy. Another man, Arizona rancher Robert “LaVoy” Finicum, was killed by local law enforcement. But four holdouts remain at the refuge, and the site remains closed. Read More
Zika virus caught the world off guard, but it shouldn’t have.
The rapid spread of the mosquito-borne virus, and its possible connection to birth defects and neurological disorders, compelled the World Health Organization on Monday to declare an international public health emergency. But by that time 1.5 million Brazilians had already caught the virus, and it had spread to 24 countries in the Western Hemisphere. The current tally from the Centers for Disease Control and Prevention indicates 30 countries are now reporting active transmission.
“It seems like we are always behind,” says Jorge Osorio, a professor of infectious diseases at the University of Wisconsin-Madison. Osorio returned to the United States on Friday after a research stint in Colombia, where the total of confirmed Zika cases is second only to Brazil. “We knew it was a matter of time before this would happen.”
There’s no doubt that a rapid global response — like what’s currently underway — is needed, but Zika’s transformation from a sleeping virus to a global crisis is all too familiar. Since the 1970s, global re-emergence of mosquito-borne infectious diseases has only accelerated. In 2001, global cases of dengue fever skyrocketed. In 2004, chikungunya re-emerged in East Africa and spread worldwide. But with every new outbreak, a recurring flaw in the approach toward infectious disease control is exposed: We’re consistently reactive.
“It’s sort of human nature. We react to the thing that’s on fire, but we aren’t so good at prevention,” says David Katz, a certified board specialist in public health and founding director of Yale University’s Yale-Griffin Prevention Research Center. “We neglect the factors that produce emerging infectious disease, and in the blink of an eye we have a global crisis on our hands.”
By the late 1960s humanity was winning its war with malaria, yellow fever, dengue and a host of other diseases. Proactive, aggressive eradication efforts eliminated the Aedes aegypti mosquito — the primary carrier of infectious diseases — in 23 countries. But our declaration of victory was specious.
Duane Gubler, a professor of emerging infectious diseases at Duke-NUS Medical School in Singapore, noted in a 2011 review that our comfort in victory kicked off a period of “increasing apathy and complacency” toward controlling infectious diseases. A new, more reactive paradigm of surveillance and emergency response was adopted for disease control, and resources shifted to other diseases.
In the four decades that followed, unprecedented population growth occurred around the world, and more people converged in crowded urban centers. Mosquitoes that once spread diseases in remote, less-populated locales had millions more human hosts to bite and infect in confined areas. On top of that, advances in global transportation made the world smaller and further enhanced the ability of viruses to expand their reach. Today, a respond-to-an-emergency approach can’t keep up with the ability of viruses to mutate and spread.
“We live in a crisis-oriented society. But this has been going on for the better part of 40 years as we’ve seen these global pandemics of infectious diseases spread,” says Gubler. “We wait for them to occur.”
Infectious disease researchers could see Zika’s warning signs long before the outbreak captured headlines. The virus was isolated in 1947 from rhesus monkeys in Uganda. Only sporadic human Zika infections were reported since its initial discovery, and its clinical presentation didn’t sound alarms. Oftentimes, infected people wouldn’t know Zika was in their system. For that reason, the virus didn’t garner much attention or warrant funding for research.
“In the United States, research for all science and infectious diseases has been at historic lows, so to get funding for Zika virus, which wasn’t causing many infections, was nearly impossible,” says Matthew Aliota, a research scientist at the UW-Madison School of Veterinary Medicine.
It wasn’t until 2007 that a Zika epidemic swept through Yap Island in the Federated States of Micronesia. A larger epidemic followed in French Polynesia in 2013-14. In May 2015, the Pan American Health Organization issued an alert about the transmission of Zika virus in Brazil. And in July, Gubler sounded the warning in an issue of The Lancet.
“We essentially predicted this months ago, and said it would follow in the footsteps of chikungunya because it has the same epidemiology,” says Gubler. “Part of our problem is that we have a mentality of looking at these viruses, including a lot of virologists, as monolithic species. These viruses change genetically, and those changes affect expression.”
Today, a virus that was largely ignored is now affecting human health in ways we didn’t anticipate. In other words, a virus that’s lying dormant doesn’t make it less of a threat to world populations. And with half the world’s population living in areas susceptible to infectious diseases, a virus that’s gone quiet doesn’t mean it won’t come roaring back.
“Yellow fever is another virus that’s sitting in the wings. It still exists in West Africa, but it’s been relegated for the past 60 years,” says Gubler. “If, or when, it starts causing trouble, it will make all of these other outbreaks pale by comparison.”
That’s why Gubler, Osorio, Katz and others advocate for going on the offensive to strike viruses before they spiral out of control — even benign viruses. With adequate resources, vaccine development could be accelerated. Mosquito populations could be kept in check. Researchers across scientific disciplines could collaborate to build ways to predict future hotspots for outbreaks and focus energies there.
“You need to rebuild public health infrastructure in endemic countries and develop the lab capacity to support a surveillance system to give you some predictive capability,” says Gubler. “That requires investment, dedication and some bit of faith on the part of policymakers that this is money well spent.”
Osorio and Aliota are working in Colombia to build more accurate laboratory diagnoses of Zika, dengue and chikungunya. The other focus of their research is to track the way Zika and viruses like it evolve and adapt in their hosts. Their research has shown that Zika split into two distinct lineages, African and Asian. The strain they’re seeing in Colombia can be traced back to the strain that existed in the 2013-14 outbreak in French Polynesia. But their work has a larger aim: predicting how viruses will mutate to get ahead of the next outbreak.
“I’m trying to be more predictive using lab studies and experimental evolution in the lab to be more proactive,” says Aliota. “It’s idealistic thinking, but we’re working to predict the evolvability and adaptability of certain viruses.”
Building a more thorough global network of early detection centers around the world is also essential for pivoting to a proactive approach to infectious disease. Expanding the reach of organizations like the Global Virus Network, which is composed of research centers around the world that focus on viral causes of human disease to prepare for novel pandemic threats, could provide enough warning stay ahead. A robust, global virus detection system could operate similarly to the global array of earthquake-detecting instruments that give advance notice of a potential disaster.
“We must continue to create those centers around the world, and ensure they are funded and equipped with people who are well trained to do this,” says Osorio. “Early indication is important, and it gives us the ability to take measures right away.”
“We need to look at culture, epidemiology, economics and ecology at a local level and develop strategies from there,” says Gubler, who helped form the Partnership for Dengue Control, which brings health experts together to do that.
Overall, infectious disease researchers are pushing toward a more interdisciplinary approach to predict outbreaks. Jonathan Patz, director of the Global Health Institute at UW-Madison, is doing research to connect the dots between climate change and global health, offering a glimpse into the ways differing scientific fields can combine to build a proactive approach to mosquito-borne disease. His research has revealed a link between dramatic climactic shifts and the occurrence of viral outbreaks.
“Extreme drought conditions tend to drive the proliferation of Aedes aegypti. Epidemics of Zika, dengue and chikungunya have been preceded by drought,” says Patz. “This year, the el Nino event is looking like the strongest on record. During el Nino, northeastern brazil is generally affected with drought.”
Patz notes there are myriad other variables that shift weather patterns and the spread of disease. But, generally speaking, he is finding that drought is a contributing factor. Patz’s work reflects a larger shift toward looking beyond the infectious agent and building a broader recognition of factors that are in play.
“It’s getting much better in terms of interdisciplinary focus,” says Aliota. “I never thought, when I first got into the hard sciences, that I would be talking to geographers, anthropologists and the other disciplines in my work.”
Of course, controlling the populations of A. aegypti, the source of the problem, is also a key area of research. Methods of population control, and wider access to mosquito nets and repellant in poor countries are essential. There’s also emerging interest in research to genetically modify mosquitoes. The research could limit their ability to breed — or wipe them out completely.
“Mosquito control has been left wanting for over 40 years, and that’s catching up with us,” says Gubler.
If there’s any silver lining from the surge in outbreaks, it’s that it brings into sharp focus the sheer connectedness of humanity. Zika, dengue and chikungunya don’t respect political borders. Outbreaks are forcing us to break long-standing lines of division and embrace the fact that we are one species.
“Zika does not give a damn about whether you are Muslim, Jewish or Christian,” says Katz. “The world is small, and there is no ‘over there anymore.’ We’re all in the same petri dish. I think that shift in thinking is fundamental to our preparedness.”
January was a good month for the planets. Scientists reported theoretical evidence for “Planet 9” and the alignment of Mercury, Venus, Saturn, Mars and Jupiter in the morning sky encouraged many people to wake up extra early to see the show.
As you likely know, these planetary alignments occur because the solar system is largely shaped like a flattened disk with the ecliptic being the plane that holds Earth’s orbit around the sun. The orbit of Mercury is inclined 7 degrees relative to the ecliptic, more than twice the inclination of any other planet. That small range of orbital inclinations relative to the ecliptic means that any time it’s viewed edge-on, the range of the planets would be very small in the direction perpendicular to Earth’s orbit. Read More
Millions of people are suffering from post-traumatic stress disorder (PTSD) right now. Among military personnel who’ve been deployed to Iraq and Afghanistan, an estimated 31 percent are PTSD sufferers. An estimated 52 percent of people with PTSD also suffer from major depressive disorder (MDD).
The cost of treating these disorders is estimated to run as high as $40 billion per year. The social consequences are harder to quantify, but many PTSD and MDD sufferers report marital problems, difficulties bonding with family and friends, and chronic suicidal thoughts.
But a team of researchers led by Andrew Leuchter, professor of psychiatry and biobehavioral sciences at UCLA, believes it has found a new treatment for PTSD and MDD. It’s not a new drug or a new form of psychotherapy. It’s a form of electronic nerve stimulation. Read More
In a 1978 essay, titled Where Am I?, the philosopher Daniel Dennett suggested that the brain was the only organ of which it’s better to be a transplant donor than recipient. Now Italian neurosurgeon Sergio Canavero wants to turn philosophical thought experiments into reality by transplanting the head of Valery Spiridonov, who suffers from a debilitating muscle wasting disease, onto the healthy body of a dead donor.
Beside posing questions about personal identity, there are more prosaic challenges that must first be overcome. The brain would have to be kept alive during surgery by cooling it to 10-15°C, and the immune system would need to be powerfully suppressed to prevent transplant rejection. But the greatest hurdle may be how to restore connections to the spinal cord. Without this connection the brain would have no control of its new body. Read More
Go is a two-player board game that originated in China more than 2,500 years ago. The rules are simple, but Go is widely considered the most difficult strategy game to master. For artificial intelligence researchers, building an algorithm that could take down a Go world champion represents the holy grail of achievements.
Well, consider the holy grail found. A team of researchers led by Google DeepMind researchers David Silver and Demis Hassabis designed an algorithm, called AlphaGo, which in October 2015 handily defeated back-to-back-to-back European Go champion Fan Hui five games to zero. And as a side note, AlphaGo won 494 out of 495 games played against existing Go computer programs prior to its match with Hui — AlphaGo even spotted inferior programs four free moves.
“It’s fair to say that this is five to 10 years ahead of what people were expecting, even experts in the field,” Hassabis said in a news conference Tuesday. Read More
One truism for me that I suspect holds some tiny bit of general truth for many across the broad, beautiful swath of humanity is that the longer I live the more history compresses.
Today the work Brahe, Kepler and Galileo did to understand the geometry of the solar system doesn’t seem as distant to me as the scenes from Happy Days did shortly after we landed on the moon. When I teach astronomy and physics I circle back to certain ideas repeatedly. One of these ideas is related to the evolving sense of the flow of time, wherever it may slip. This concept centers on my need to get students to come to terms with the notion that the ideas in their textbooks got there as a result of real struggles by real people. As clear and obvious as the textbook physics may appear, it almost assuredly was a dirty mess at the time. Read More