We weren't the only ones to notice Krauss's "shenanigans" duringSaturday's debate with Meyer and Lamoureux. Over at his blogSandwalk, biochemist Larry Moran of the University of Toronto (where the event took place) posted a straightforward commentary, without innuendo or name-calling (aside from his usual label of "intelligent design creationists").
The main point that he picked up from Stephen Meyer's presentation was the argument that ID predicted the functionality of most of the genome, rather than its being mostly junk. ID proponent Richard Sternberg made this claim in the 1990s, and it is being confirmed by ongoing research and the ENCODE project. Moran argues that ENCODE doesn't demonstrate what ID proponents claim, and that the genome still is full of junk. But that's an argument that time and more research will answer.
The really interesting thing is what happened in the comments section after the post. He acknowledged that some ID proponents do science in good faith (in contrast to Krauss's repeated assertions during the debate):
I believe that there are ID proponents who are attempting to perform science in good faith.
Let's not quibble over when ID proponents made a prediction and whether it counts as a true predication [sic]. Right now, they are staking the reputation of ID on the claim (= prediction) that most of our genome is functional.
We'll see what happens when they realize the truth.
Then further on, in response to an attack on ID by a poster he says,
Bill says,
But the point is moot. ID is not a scientific endeavor. Never has been. It's a political movement with a social agenda to inject religion into American public schools. Simple as that.
The debate took place in Canada where we allow the teaching of religion in public schools. None of us give a damn about the American Constitution. We're interest[ed] in knowing whether the science is valid or not.
If the Intelligent Design proponents have legitimate complaints about evolution and if they have good scientific arguments in favor of design then those ideas should be taught in Canadian schools in spite of what some judge in Pennsylvania said ten years ago.
Lawrence Krauss tried to show that ID was not science but he did a horrible job. Meyer countered by presenting a lot of science forcing Krauss to deal with the very science that he said ID doesn't do!
Bill, you are being dangerously naive if you think you can simply dismiss the ID movement because it's not science (according to your definition). The general public doesn't care. All they see is serious attacks on evolution that look a lot like science.
Yes, ID is a movement and so are the desires to do something about climate change or GMO's. There are lots of "movements" with social and political agenda[s]. Many of them deal with science in one way [or] another. It's the role of scientists to evaluate the scientific arguments in spite of the agenda. We have to show that the goal of the movement is either compatible or incompatible with the scientific facts.
Yes. That's the level at which the debate should be held.
It doesn't mean that Moran agrees with us. He's just being fair. He even granted Meyer some points in the debate, before expressing his own view:
During the debate, Stephen Meyer emphasized [the] random nature of evolution and its inability -- according to him -- to come up with new protein folds and new information in a reasonable amount of time.
Krauss misunderstood the argument, which was based on the frequency of mutations, and tried to dismiss it by pointing out that evolution is not random -- it's directed and guided by natural selection.
Meyer corrected him by pointing out that the issue was the probability of mutations and not the probability of fixation once the mutation occurred. (This was when he was struggling with a migraine so he didn't do as good a job as he could have.)
Krauss stumbled on for a bit emphasizing natural selection and the fact that evolution is not random.
That was embarrassing. I think Krauss gets most of his information about evolution from Richard Dawkins so he (Krauss) probably doesn't know about random genetic drift or historical contingency or any of the other features of the history of life that make it "random" (in the colloquial sense).
I suspect that Krauss still holds on to the Dawkins view that life has the appearance of design. Truth is, in the big picture, life really doesn't have the appearance of design. Certainly our genome doesn't look designed and my back was not designed for walking upright as it let's me know every morning when I get out of bed.
Designed or not, Professor Larry Moran has distinguished himself as someone even-handed in his assessment of this debate. Thanks for the voice of reason, Dr. Moran.
What is carbonic anhydrase and why does it matter? The presence of this enzyme in salmon hearts points to another case of intelligent design in these remarkable fish that were depicted in Illustra Media's film Living Waters. News via the Journal of Experimental Biology explains the challenge salmon face swimming upstream:
Fish plumbing is contrary. As the heart is the last organ that blood passes through before it returns to the gills, and with little direct blood supply to the ceaselessly contracting muscle, there are occasions when it could be on the verge of failure. 'We know this can happen under certain conditions like exhaustive exercise in combination with hypoxia or elevated water temperature', says Sarah Alderman from the University of Guelph, Canada. Added to the challenge of keeping the heart supplied with oxygen, Alderman explains that the haemoglobin that carries oxygen in fish blood is finely tuned to blood pH: the more acidic the red blood cells, the less able haemoglobin is to carry oxygen, which could prevent the red blood cells of exercising fish from picking up oxygen at the gills if they didn't have an effective pump to remove acid from the cells and restore the pH balance. [Emphasis added.]
Here we see a double challenge the salmon faces. It has to avoid excess acid so that the hemoglobin can carry oxygen, and it has to get the oxygen all the way from the gills through its entire body to the heart. Here's where carbonic anhydrase comes to the rescue:
But Alderman and her colleagues, Till Harter, Tony Farrell and Colin Brauner from the University of British Columbia, Canada, also knew that fish can take advantage of a sudden drop in red blood cell pH to release oxygen rapidly at tissues -- such as red muscle and the retina -- when required urgently. An enzyme called carbonic anhydrase -- which combines CO2 and water to produce bicarbonate and acidic protons, and vice versa -- lies at the heart of this mechanism. Normally there is no carbonic anhydrase in blood plasma; however, the enzyme has been found in salmon red muscle capillaries, where it facilitates the reaction of protons -- that have been extruded from the red blood cell -- with bicarbonate to produce CO2, which then diffuses back into the red blood cell. The CO2 is then converted back into bicarbonate and protons in the blood cell, causing the pH to plummet and release a burst of O2 from the haemoglobin. Could salmon take advantage of this mechanism to boost oxygen supplies to the heart when the animals are working full out? Possibly, but only if carbonic anhydrase was accessible to blood passing through the heart.What is carbonic anhydrase and why does it matter? The presence of this enzyme in salmon hearts points to another case of intelligent design in these remarkable fish that were depicted in Illustra Media's film Living Waters. News via the Journal of Experimental Biology explains the challenge salmon face swimming upstream:
Fish plumbing is contrary. As the heart is the last organ that blood passes through before it returns to the gills, and with little direct blood supply to the ceaselessly contracting muscle, there are occasions when it could be on the verge of failure. 'We know this can happen under certain conditions like exhaustive exercise in combination with hypoxia or elevated water temperature', says Sarah Alderman from the University of Guelph, Canada. Added to the challenge of keeping the heart supplied with oxygen, Alderman explains that the haemoglobin that carries oxygen in fish blood is finely tuned to blood pH: the more acidic the red blood cells, the less able haemoglobin is to carry oxygen, which could prevent the red blood cells of exercising fish from picking up oxygen at the gills if they didn't have an effective pump to remove acid from the cells and restore the pH balance. [Emphasis added.]
Here we see a double challenge the salmon faces. It has to avoid excess acid so that the hemoglobin can carry oxygen, and it has to get the oxygen all the way from the gills through its entire body to the heart. Here's where carbonic anhydrase comes to the rescue:
But Alderman and her colleagues, Till Harter, Tony Farrell and Colin Brauner from the University of British Columbia, Canada, also knew that fish can take advantage of a sudden drop in red blood cell pH to release oxygen rapidly at tissues -- such as red muscle and the retina -- when required urgently. An enzyme called carbonic anhydrase -- which combines CO2 and water to produce bicarbonate and acidic protons, and vice versa -- lies at the heart of this mechanism. Normally there is no carbonic anhydrase in blood plasma; however, the enzyme has been found in salmon red muscle capillaries, where it facilitates the reaction of protons -- that have been extruded from the red blood cell -- with bicarbonate to produce CO2, which then diffuses back into the red blood cell. The CO2 is then converted back into bicarbonate and protons in the blood cell, causing the pH to plummet and release a burst of O2 from the haemoglobin. Could salmon take advantage of this mechanism to boost oxygen supplies to the heart when the animals are working full out? Possibly, but only if carbonic anhydrase was accessible to blood passing through the heart.
Well, what do you know! That's what Alderman's team found: the enzyme is present on the surface of the heart chambers. Using the heart itself as their "reaction vessel," they were able to see the pH plummet as the enzymes went into gear.
Working closely together, the duo painstakingly developed a technique where they could measure the pH in the beating heart with pH probes that were thinner than a human hair. Eventually, the duo's persistence paid off and the pH in the heart plummeted as they fed CO2 into the pulsating chambers. And when they added a carbonic anhydrase inhibitor (produced by Claudia Supuran) to the fluid, the pH fall slowed dramatically. Carbonic anhydrase was responsible for the drop in pH.
The Protein Data Bank 101 website shows pictures of this enzyme and describes its mode of action.
An enzyme present in red blood cells, carbonic anhydrase, aids in the conversion of carbon dioxide to carbonic acid and bicarbonate ions. When red blood cells reach the lungs, the same enzyme helps to convert the bicarbonate ions back to carbon dioxide, which we breathe out. Although these reactions can occur even without the enzyme, carbonic anhydrase can increase the rate of these conversions up to a million fold.
There's an evolutionary conundrum about this enzyme: functional equivalence without sequence similarity:
This ancient enzyme has three distinct classes (called alpha, beta and gamma carbonic anhydrase). Members of these different classes share very little sequence or structural similarity, yet they all perform the same function and require a zinc ion at the active site. Carbonic anhydrase from mammals belong to the alpha class, the plant enzymes belong to the beta class, while the enzyme from methane-producing bacteria that grow in hot springs forms the gamma class. Thus it is apparent that these enzyme classes have evolved independently to create a similar enzyme active site.
Further complicating the picture, there are different forms of the enzymes depending on the tissue or cellular compartment they are located in. These allow fine tuning of the enzyme's activity: "Thus isozymes found in some muscle fibers have low enzyme activity compared to that secreted by salivary glands," in the case of mammals.Carbonic anhydrase (CA) was the first enzyme found to contain zinc, abiochemistry textbooksays; now, hundreds are known. Zinc and other metals are often essential for function in metalloenzymes. The PDB-101 article explains,
Zinc is the key to this enzyme reaction. The water bound to the zinc ion is actually broken down to a proton and hydroxyl ion. Since zinc is a positively charged ion, it stabilizes the negatively charged hydroxyl ion so that it is ready to attack the carbon dioxide.
It's not surprising that this enzyme is present in the salmon, since it exists in all three domains of life. What's amazing is that the salmon's heart is studded with these enzymes that are "at the ready" when the large fish is fighting with all its might to leap above cascades and waterfalls, facing daunting challenges without the benefit of food. (Living Waters says, "The sockeye are so focused on their objective that after leaving the ocean, they do not eat again.")
If the pH dropped too early as the blood travels through the salmon's body, it would be less able to carry its precious oxygen cargo. But right when it is needed during that Olympic high jump over a waterfall or away from a hungry bear, the fish uses its CA enzymes in its heart to drop the pH and release the oxygen it needs. The spent blood then travels to the gills to load up with more oxygen. In the original paper in the Journal of Experimental Biology, the authors summarize what they found:
Combined, these results support our hypothesis of thepresence of an enhanced oxygen delivery system in the lumen of a salmonid heart, which could help support oxygen delivery when the oxygen content of venous blood becomes greatly reduced, such as after burst exercise and duringenvironmental hypoxia.
How many independent systems do we see at work in the remarkable migration of the salmon? The fish has a built-in map of its destination. It has the ability to memorize waypoints by smell. It can navigate by the earth's magnetic field. It has a sixth sense, the lateral line. It can distinguish odors by parts per trillion. Each of its body systems contain thousands of molecular machines like carbonic anhydrase that are located just where they need to be, doing what they need to do to support the whole organism.
If any one of these systems is a testament to intelligent design, how much more the composite? The only fish story here is the notion that all this came together by unguided natural processes -- sheer dumb luck.
The term "Establishment" is controversial. It invariably implies a critical stance, suggesting a system, a power structure, in need of a shakeup or worse. It's not a description anyone would welcome having applied to himself. Nobody wants to be seen as defending entrenched privilege. Depending on the context, some deny the existence of such an entity to begin with.
What about in the world of science, and specifically biology? Is it fair to speak of an Establishment there, primed to be updated by "rogue" outside forces? It seems so. Or perhaps "rigidly calcified mindset" is the better phrase. Today in the New York Times, Amy Harmon reports on hints of decalcification, a modest but significant move in science research publishing toward "preprints." That is, publishing directly online without first submitting your work to the official gatekeepers: peer-reviewed journals.
Don't worry -- it's not as if this research then goes unreviewed or uncriticized. Instead the review process happens immediately and organically. Those interested enough to read your work can tell anyone and everyone what they think. Minus the online aspect, it's the way Charles Darwin published his ideas:
It was a small act of information age defiance, and perhaps also a bit of a throwback, somewhat analogous to Stephen King's 2000 self-publishing an e-book or Radiohead's 2007 release of a download-only record without a label. To commemorate it, she tweeted the website's confirmation under the hashtag #ASAPbio, a newly coined rallying cry of a cadre of biologists who say they want to speed science by making a key change in the way it is published.
Such postings are known as "preprints'' to signify their early-stage status, and the 2,048 deposited on three-year-old bioRxiv over the last year represent a barely detectable fraction of the million or so research papers published annually in traditional biomedical journals.
But after several dozen biologists vowed to rally around preprints at an "ASAPbio'' meeting last month, the site has had a small surge, and not just from scientists whose august stature protects them from risk. On Twitter, preprint insurgents are celebrating one another's postings and jockeying for revolutionary credibility.
One diagnostic of a genuine Establishment would be that its members maintain that the system, for everyone's good, couldn't be much different from how it is. In this case, there's nothing necessary about the traditional manner in which biologists publish their work. Physics, as Harmon notes, has had preprints for decades, and the field is healthier for it:
Unlike physicists, for whom preprints became a default method of communicating discoveries in the 1990s, biomedical researchers typically wait more than six monthsto disseminate their work while they submit it -- on an exclusive basis -- to the most prestigious journal they think might accept it for publication. If, as is often the case, it is rejected, they try another journal. As a result, it can sometimes take years to publish a paper, which is then typically available for a time only to colleagues at major academic institutions whose libraries pay for subscriptions. And because science is in many ways a relay, with one scientist building on the published work of another, the communication delays almost certainly slow scientific progress.
True, it's not that preprints are intended to replace traditional publishing. Those interviewed for the article are careful to say they aren't rejecting the big journals. You wouldn't want to offend the Establishment!
Many have taken pains to reiterate their wish not to disrupt the journal system, only to enhance it. With enough scientists pushing to legitimize preprints, they hope journals will allow the systems to coexist.
"It's not beer or tacos," as James Fraser, an assistant professor at the University of California, San Francisco put itat last month's conference, "it's beer AND tacos."
Still, this sounds exactly like a revolt, if mild, seeking to slip out from under some of the bonds of a burdensome hierarchy -- one that up till now has controlled the flow of ideas and artificially constrained debate through access and credentialing, with an eye to maintaining its own power and prestige. What will it mean for insurgent scientific ideas like intelligent design and the critique of Darwinism? Time will tell, but the development seems like a hopeful one.
Collective Motion: A New Level of Design Found in Proteins
Evolution News & Views March 15, 2016 3:06 AM
A "previously unidentified mechanism for modulating protein affinity" has come to light. A team of scientists at the Max Planck Institute for Biochemical Chemistry, publishing in the Proceedings of the National Academy of Sciences, has identified new functional roles for collective motions within protein molecules. These motions, referred to as allostery, allow one end of the protein to affect a distant part through what is termed "allosteric communication."
Intermolecular interactions are one of the key mechanismsby which proteins mediate their biological functions. For many proteins, these interactions are enhanced or suppressed by allosteric networks that couple distant regions together. The mechanisms by which these networks function are just starting to be understood, and many of the important details have yet to be uncovered. In particular, the role of intrinsic protein motion and kinetics remains particularly poorly characterized. [Emphasis added.]
This is cutting-edge research. The team studied a common protein named ubiquitin which, as the name implies, is ubiquitous in the cell. It serves as a molecular "tag" on other molecules slated for degradation by the proteasome. As such, it needs to form connections with the proteasome and with a variety of other proteins. What they found is that distant parts of the molecule could affect binding affinity of other parts through motions transmitted throughout the entire molecule.
To determine how this collective motion influences bindingand other functions of ubiquitin (e.g., presence of different covalent linkages), we performed an extensive structural bioinformatics survey of known ubiquitin crystal structures. Because the peptide bond conformation was the most recognizable feature of the collective mode, we used its conformation as a "marker" for structural discrimination. Themost significant relationship we found was the universal association between the NH-in state and binding to the ubiquitin-specific protease (USP) family of deubiquitinases (Fig. S11). This association has been previously noted and issurprising because the peptide bond is at least 6.8 Å from any USP (Fig. 3A).
By comparing mutants with wild-type forms, the team found several kinds of motion that involve twisting, rocking and stretching. Mutations on a peptide bond between two specific amino acid residues, in particular, had a surprising effect, reducing binding affinity by a factor of 10 (or abolishing it altogether). This suggests low tolerance for mutation.
They found "strong allosteric coupling between opposite sides of the protein" in some cases. "Given the relative subtlety of the expansion and contraction" of allosteric interactions, they found it "surprising" again that two different states could produce large effects. It implies that ubiquitin and its ligand "appear to adapt their conformations mutually to establish a complementary binding interaction" for best fit at the appropriate times.
One mutant showed a two-fold weaker affinity for its particular USP. "Although this change may seem like a moderate effect," they note, "it isactually surprisingly large and highly significant when one considers that it is allosterically triggered by the simple rotation of a solvent-exposed peptide bond on a distal side of the protein."
These motions are so rapid -- on the order of microseconds -- they were not really considered significant until recently. Other motions they mention, like "pincer time" and "tumbling time," occur on different time scales, the former being quicker, the latter being much slower. This may suggest a kind of timing code for different functions.
Their conclusions reveal a significant new area of study: switch-controlled "allosteric communication" in protein molecules:
This study revealed an allosteric switch affecting protein-protein binding through collective protein motion at the microsecond time scale.... Whereas most known microsecond to millisecond time-scale motions involve excursions to excited, lowly populated states, this motion occurs between two ground state ensembles with nearly equal populations (NH-in and NHout). Strikingly, the peptide bond conformation is allosterically coupled through a diverse set of interactions that triggers contraction/ expansion of the entire domain. This type of global domain motion reveals apreviously unidentified mechanism for modulating protein affinity. The presence of this allosteric network suggeststhere may be heretofore undiscovered ways in which macromolecular assemblies and covalent linkages regulate ubiquitin binding. More broadly, this study demonstrates how relatively modest changes in hydrogen bond networks and the protein backbone can bring about distant changes in protein conformation and binding affinity.
We encounter, therefore, a whole new level of specificity in protein architecture. It's not the old picture of an active site surrounded by haphazard amino acid residues. Any change could affect the allosteric communication of the whole protein. Clearly, mutants were less able to take advantage of the benefits of collective motion.
How did an unguided process arrive at a molecular machine that not only grips its substrate and catalyzes a reaction efficiently, but moves with intrinsic twists and stretches to improve the grip? The design specs for proteins just shot up a notch, and along with them, the challenges to Darwinian evolution.
My Debate with Michael Ruse -- Evolution as a Rube Goldberg Machine
Cornelius Hunter March 17, 2016 3:32 AM
Editor's note: Evolution News is delighted to welcome back Dr. Hunter as a contributor. He is a Fellow with the Center for Science & Culture, Adjunct Professor at Biola University, and author of the award-winning Darwin's God: Evolution and the Problem of Evil. He blogs at Darwin's God
It was great to see Professor Michael Ruse again last week in Northern California for our debate on the question, "Is Evolution Compelling?" He was in good spirits as usual, and his jokes were much better than mine. But I had one big advantage over my erudite opponent: I was not defending the age-old idea that the world of life arose by chance. The main problem, as I explained at the outset, is that the scientific evidence contradicts unguided evolution. That is a very simple point, but it opens new worlds of thought.
I used my time to discuss a range of scientific evidence from biology. On that evidence, unguided evolution simply makes no sense. But I almost hesitate to show you my list simply because there is nothing special about it. One of the difficulties in explaining the problems with evolution to an audience is the plethora of examples from which to choose. I had a long list of fascinating biological designs that refute evolutionary thought. I like every one of them, because they all add a different angle on why evolution fails. But there are far too many to fit into an evening's presentation. I was changing my mind right up to the last day, but as difficult as it is, one must pare back the list to fit the time constraint.
I began with one of my favorites, micro RNA. I then discussed the failure of evolution's nested hierarchy. Later I had fun with echolocation and the DNA code, and I finished with directed adaptation. The obvious and unavoidable truth is that evolution is believed to be a fact not because of the science, but despite the science.
I also punctuated my scientific examples with some philosophy of science concerns. One of them is the problem of parsimony. I explained Occam's Razor, and how a sure sign of a failing theory is if it becomes overly complicated. The appeal of heliocentrism over geocentrism was not that of an improvement in accuracy, but in simplicity. Like heliocentrism, Copernicus' geocentrism had epicycles. So why make the move? Because Copernicus was able to use fewer epicycles. That is how important simplicity is in science.
Theory complexity is the enemy in science, and it would require volumes to explain all the details in today's theory of evolution. The reason why evolution is so complicated is that with each scientific failure, the theory is adjusted yet again. Today it resembles one of Rube Goldberg's wonderful machines.
For this theory, there is no ray of hope. I think I left the audience convinced that evolution is an utterly failed attempt. That's not because of any rhetorical skills on my part, but simply because I took the side of science. This isn't at all complicated. What is complicated is the question of why people believe in evolution to begin with. But that's another story.
That’s where the EHT comes in. Since the EHT first started taking data, it has been building its telescope roster, and with each new member, it gets closer to making the first true image of a black hole shadow.
The EHT is like an all-star team of telescopes: Most days, its millimeter-wave dishes run their own experiments independently, but for one or two weeks a year, they team up to become the EHT, taking new data and running tests during the brief window when astronomers can expect clear weather at sites from Hawaii to Europe to the South Pole.
“It sounds too good to be true that you just drop telescopes around the world and ‘poof!’ you have an Earth-sized telescope,” says Avery Broderick, a theoretical astrophysicist at University of Waterloo and the Perimeter Institute. And in a way, it is. The EHT doesn’t make pictures. Instead, it turns out a kind of mathematical cipher called a Fourier transform, which is like the graphic equalizer on your stereo: it divvies up the incoming signal, whether its an image of space or a piece of music, into the different frequencies that make it up and tells you how much power is stored in each frequency. So far, the EHT has only given astronomers a look at a few scattered pixels of the Fourier transform. When they compare those pixels to what they expect to see in the case of a true black hole, they find a good match. But the job is like trying to figure out whether you’re listening to Beethoven or the Beastie Boys based only on a few slivers of the graphic equalizer curve.
Now, the EHT is about to add a superstar player: the Atacama Large Millimeter Array, a telescope made up of 66 high-precision dishes sited 16,000 feet above sea level in Chile’s clear, dry Atacama desert. With ALMA on board, the EHT will finally be able to make the leap from fitting models to seeing a complete picture of the black hole’s shadow. EHT astronomers are now rounding up time at all of the telescopes so that they can take new data and assemble that first coveted image in 2017.
And if they don’t see what they expect? It could mean that the black hole isn’t really a black hole at all.
That would come as a relief to many theorists. Black holes are mothers of cosmic paradox, keeping physicists up at night with the puzzles they present: Do black holes really destroy information? Do they really contain infinitely dense points called singularities? Black holes are also the battlefield on which general relativity and quantum mechanics clash most dramatically. If it turns out that they don’t actually exist, some physicists might sleep a little better.
But if they’re not black holes, then what could they be? One possibility is that they are dark stars made up of bosons, subatomic particles that, unlike more familiar electrons and protons, obey strange rules that allow more than one of them to be in the same place at the same time. Boson stars are highly speculative—astronomers have never seen one, as far as they know—but theorists like Vitor Cardoso, a professor of physics at Técnico in Lisbon and a distinguished visiting researcher at Sapienza University of Rome, hypothesize that some or all of the objects we think are supermassive black holes could actually be boson stars in disguise.
Physicists classify particles into two different categories: fermions, which include protons, electrons, neutrons, and their components; and bosons, like photons (light particles), gluons, and Higgs particles. Every star that we’ve ever seen shining is dominated by fermions. But, Cardoso says, given a starting environment rich in bosons, bosons could “clump” together gravitationally to form stars, just as fermions do. The early universe might have had a high enough density of bosons for boson stars to form.
But not every boson is a suitable building block for a boson star. Gravity won’t hold together a clump of massless photons, for instance. Higgs particles are massive enough to be bound together by gravity, but they aren’t stable—they only exist for tiny fraction of a second before decaying away. Theorists have speculated about ways to stabilize Higgs particles, but Cardoso is more intrigued by the prospect that other, yet-undiscovered heavy bosons, like axions, could make up boson stars. In fact, some physicists hypothesize that massive bosons like these could be responsible for dark matter—meaning that boson stars wouldn’t just be a solution to the riddle of black holes, they could also tell us what, exactly, dark matter is.
Gravastars
Boson stars aren’t the only black hole doppelgänger that theorists have dreamed up. In 2001, researchers proposed an even more speculative oddity called a gravastar. In the gravastar model, as a would-be black hole collapses under its own weight, extreme gravity combines with quantum fluctuations that are constantly jiggling through space to create a bubble of exotic spacetime that halts the cave-in.
Theorists don’t really know what’s inside that bubble, which is both good and bad news for gravastars: Good news because it gives theorists the flexibility to revise the model as new observations come in, bad news because scientists are rightly skeptical of any model that can be patched up to match the data.
When the data does come in, physicists have a checklist of sorts that should help them know which of the three—black hole, boson star, or gravastar—they’re looking at. A gravastar should have a bright surface that’s distinguishable from the glowing ring predicted to loop around a black hole. Meanwhile, if the object at the center of the Milky Way is actually a boson star, Cardoso predicts, it will look more like a “normal” star. “Black holes are black all the way through,” Cardoso says. “If really the object is a boson star, then the luminous material can in principle pile up at its center. A bright spot should be detected right at the center of the object.”
A New View
Most physicists have placed their bets on Saggitarius A* and other candidates being black holes, though. Boson stars and gravastars already have a few strikes against them. First, when it comes to scientific credibility, black holes have a major head start. Astronomers have a solid understanding of the process by which black holes form and have direct evidence that other ultra-dense objects, like white dwarfs and neutron stars, which could merge to form black holes, really do exist. The alternatives are more speculative on every count.
Furthermore, Broderick says, astronomers have looked for the telltale signature of boson stars and gravastars at the center of the Milky Way—and haven’t found it. “The stuff raining down on the object will give up all its kinetic energy—all the gravitational binding energy tied up in the kinetic energy of its fall—resulting in a thermal bump in the spectrum,” Broderick says —that is, a signature spike in infrared emission. In 2009, astrophysicists reported that they had found no such bump coming from Sagittarius A*, and in 2015, they announced that it was missing from the nearby massive galaxy M87, too.
Cardoso doesn’t see this as a death-knell for the boson star model, though. “The field that makes up the boson star hardly interacts with matter,” he says. To ordinary matter, the surface of a boson star would feel like frothed milk. “We do not yet have a complete model of how these objects accrete luminous matter,” Cardoso says, “so I think that it’s fair to say that this is still an open question.” He is less optimistic about gravastars, which he describes as “artificial constructs” that are likely ruled out by the latest observations.
As the LIGO experiment gathers more data, theorists will get more opportunities to test their exotic hypotheses with gravitational waves. As two massive objects—say, a supermassive black hole and a star—spiral toward each other on the way toward a collision, gravitational waves carry away the energy of their motion. If one member of the spiraling pair is a black hole, the gravitational wave signal will cut off abruptly as the star passes through the black hole’s event horizon. “It gives rise to a very characteristic ringdown in the final stages of the inspiral,” Cardoso says. Because the alternative models have no such horizon, the gravitational wave signal would keep on reverberating.
Most astronomers believe that the waves LIGO detected were given off by the collision of two black holes, but Cardoso thinks that boson stars shouldn’t be ruled out just yet. “The data is, in principle, compatible with the two colliding objects being each a boson star,” he says. The end result, though, is probably a black hole “because it rings down very fast.”
LIGO is not designed to pick up signals at the frequency at which supermassive objects like Sagittarius A* are expected to “ring.” (LIGO is tuned to recognize gravitational waves from smaller black holes and dense stars like neutron stars.) But supermassive black holes and boson stars are in the sweet spot for the planned space-based gravitational wave telescope eLISA (the Evolved Laser Interferometer Space Antenna), slated for launch in 2034. “To confirm or rule out boson stars entirely, we need ‘louder’ observations,” Cardoso says. “EHT or eLISA are probably our best bet.”
Taking the Pulse
In the meantime, astronomers could measure waves from these extremely massive objects by precisely clocking the arrival times of radio pulses from a special class of dead stars called pulsars. If astronomers spot pulses arriving systematically off-beat, that could be a sign that the space they’ve been traveling across is being stretched and squeezed by gravitational waves. Three collaborations—NANOGrav in North America, the European Pulsar Timing Array, and the Parkes Pulsar Timing Array in Australia—are already scanning for these signals using radio telescopes scattered around the globe.
To Broderick, though, the big question isn’t which model will win out, it’s whether these new experiments can find a flaw in general relativity. “For 100 years, general relativity has been enormously successful, and there’s no hint of where it breaks,” he says. Yet general relativity and quantum mechanics, which appears equally shatterproof, are fundamentally incompatible. Somewhere, one or both must break down. But where? Boson stars and gravastars might not be the answer. Still, exploring these exotic possibilities forces physicists to ask the questions that might lead them to something even more profound.
“We expect that general relativity will pass the EHT’s tests with flying colors,” Broderick says. “But the great hope is that it won’t, that we’ll finally find the loose thread to pull on that will unravel the next great revolution in physics.”
Transhumanism is a materialistic religion that seeks to attain the comforts provided by faith through belief in technology as savior. One aspect of the movement is the quest for eternal life. Now, a hyper-rich Russian mogul hopes to live forever by uploading his personality to a robot. From the Telegraph story:
Web entrepreneur Dmitry Itskov is behind the "2045 Initiative", an ambitious experiment to bring about immortality within the next 30 years by creating a robot capable of storing human personalities.
The group of neuroscientists, robot builders and consciousness researchers say they can create an android that is capable of uploading someone's personality.
Mr Itskov, who has made a reported £1bn from his Moscow-based news publishing company, is the project's financial backer.
They believe that robots can store a person's thoughts and feelings because brains function in the same way as a computer.
Says Itskov, "Different scientists call it uploading or they call it mind transfer. I prefer to call it personality transfer."
Even if they could do this, however, so what? Whatever programming the robot was able to access, "Robot Itskov" still wouldn't be Itskov. Our beings are so much more than what we think and remember. For example, there are the subconscious, physical sensations caused by stimuli that trigger hormones and body chemicals, the experience of emotions, and for those who believe in such things, the spiritual element.
No matter how powerful the algorithms that governed an "immortality robot's" programming, it would exhibit -- at most -- a faux or mimicking of "personality." The person being mimicked -- the being the robot was supposed to have become -- would not be present.
