It's not quite Rise of the Planet of the Apes, but it may not be too far off, either. By grafting human glial cells into the brains of mice, neuroscientists were able to "sharply enhance" their cognitive capacities. These improvements included augmentations to memory, learning, and adaptive conditioning. It's a breakthrough that could yield important insights into the treatment of human brain disorders.

To conduct the experiment, the scientists created human chimeric mice — mice that were endowed with human glial cells.

Grafting Glia

These star-shaped cells are among the most abundant cells in the brain, performing various tasks like biochemical support of endothelial cells, supplying nutrients to nervous tissue, and repair.

But scientists have also speculated that glial cells play an important role in both our intellectual and cognitive processing capacities. And indeed, previous studies have shown that astrocytes (a type of glial cell) regulate synaptic transmission and improve the efficiency of neural circuits. This has led some neuroscientists to wonder if astrocytic evolution may be connected to the increased scope and capacity of central neural processing in humans.

To push this line of inquiry further, the University of Rochester Medical Center's Steve Goldman, along with Maiken Nedergaard, set about the task of engineering mice with brains infused with human glial cells to see it would have any kind of influence on their cognitive capacities.

Now it's important to note that mice have glial cells, too. But they're quite different from ours.

"Human glia are larger and have more fibers than those of lower species, and as a result each controls many more neural synapses within its geographic domain, compared to similarly situated mouse astrocytes," Goldman told io9. "In addition, human cells may secrete higher levels of neuromodulators and cytokines that regulate synaptic activity."

In particular, Goldman and Nedergaard identified TNFalpha, an important modulating cytokine.

And these morphological differences in glia matter; because astrocytes can both coordinate and control neural signal transmission, the researchers wanted to know if they would function differently in different species. To date, the only relevant studies have been done on rodent brains — brains with glial cells that are markedly different than our own.

So, to give mice human glia, the scientists delivered the cells into the brains of normal newborn mice.

"We did this by using a narrow glass micropipette to inject 100,000 human glial progenitor cells into each hemisphere of the developing mouse forebrain," said Goldman. This resulted in the widespread integration of human glia into their brain. Once the mice reached adulthood, a large proportion of their forebrain glia were essentially human.

To mitigate any ethical concerns, Goldman told io9 that the grafts were delivered into postnatal animals, they were of cells that could not be transmitted to offspring, and they did not involve neuronal replacement.

Improved Information Processing

Once adulthood was reached, the neuroscientists put the mice through four different cognitive tests. The results showed that the humanized mice were markedly different than their unenhanced brethren.

"The engrafted mice acquired new conditional associations and learned tasks significantly more rapidly than did their unengrafted — or mouse cell-grafted — controls," Goldman told us.

Specifically, long-term potentiation (the increase in strength of nerve impulses along previously used pathways) was sharply enhanced in the human glial chimeric mice, as was their learning. They did a better job navigating through mazes (as per the Barnes maze navigation protocol), their object-location memory was superior, and their fear conditioning was enhanced (both for contextual situations and alarming tones).

On the other hand, mice who were grafted with murine GPCs (glial cells extracted from other rodents), showed no enhancement in any of these areas.

"These findings indicate that human glia differentially enhance both activity-dependent plasticity and learning in mice," noted the authors in the ensuing study.

This research strongly suggests that glia plays a species-specific role in species-specific intellectual and cognitive processing capabilities, a revelation that presents some interesting insights into human evolution. As a result, the researchers hope to see related studies conducted in the live adult brain.

Treating Human Brain Disorders

And indeed, in a parallel study published in Cell Stem Cell last month, Goldman's team described how to efficiently generate glial progenitor cells from human skin cells reprogrammed into induced pluripotential cells.

"As a result, we can now establish glial progenitor cells on a patient-specific basis from individuals with brain diseases, including a number of neuropsychiatric as well as neurological disorders that appear relatively specific to humans," Goldman told us.

Consequently, neuroscientists will now be able to determine the role that glial cells play in these disorders (including failing glial cells), and to do so in live animals. This will present a better method for evaluating potential treatments for human brain disorders.

Looking ahead, Goldman is hoping to engineer humanized mice with glial cells derived from patients with Huntington's Disease, which will allow his team to see if there's any connection to the cognitive deterioration in patients with that disease.

You can read the study, "Forebrain engraftment by human glial progenitor cells enhances synaptic plasticity and learning in adult mice," in Cell Stem Cell.

Images: Top: lculig/shutterstock.com; Steve Goldman/University of Rochester.

Shortly after the 1942 deployment of the U.S. Eighth Air Force in Britain, LIFE Magazine sent Margaret Bourke-White to spend time with the now legendary VIII Bomber Command. During her assignment, she managed to snap a series of color photographs, many of which never actually made it to her feature article. Over 70 years later, LIFE has finally released these unpublished color photos.

All images via LIFE.

Not a bad way to spend the time.

The finished product. Givin' it to the Axis leaders.

The Boeing B-17 Flying Fortress. It had un uncanny ability to survive heavy fire, was easy to maneuver, and was popular among its crews for its reliability.

Check out how young this guy looks.

They're definitely going to need those. The B-17s had unpressurized cabins, and with planes reaching upwards of 39,700 feet, crew members were exposed to sub-zero temperatures.

The rear turret featured two 12 x 0.5 inch Browning machine guns.

I don't imagine he'd fly without it.

Dogs were common at the bases and were typically spoiled rotten by homesick, stressed-out crews.

An American bomber crew waiting for their next mission over Nazi-occupied Europe.

There's plenty more at LIFE, including more photos and some excerpts from the actual text that appeared in Margaret Bourke-White's feature article.

It was starting to get so bad for Ontario's Kim Rollins that her mother started to make plans for the funeral. Conventional therapies weren't helping to alleviate her severe anorexia, so Rollins decided to volunteer for a cutting-edge treatment: deep-brain stimulation. Now, with her "brain pacemaker," she has been effectively treated for the condition. The breakthrough suggests that DBS could be used to help similar patients.

The therapy was conducted by a team of neurosurgeons and psychiatrists from Toronto who worked with six women. Three have gained weight, and all them have reported improvements in mood nine months after the surgery.

The Globe and Mail reports:

"I am now 120 pounds – which is a healthy body weight for a person my age and height of five feet, 21/2 inches," she said. Before the brain surgery, she weighed 90 pounds. And perhaps even more significant, she is no longer troubled by the same degree of anxiety, depression and obsessive behaviour that caused her to put her own life in jeopardy with excessive dieting.

Indeed, the most interesting thing about this therapy is that it isn't targeting the anorexia specifically, but rather the mood disorders associated with it.

The G&M continues:

"What we find particularly exciting about the study is that the treatment was associated with a very significant improvement in their mood and a reduction in their obsessional symptoms. And we think that is the key if we are going to have an enduring effect on this illness," said one of the researchers, Dr. Andres Lozano, a neurosurgeon at the Krembil Neuroscience Centre of Toronto Western Hospital and a professor at the University of Toronto.

The treatment, though, will require patients to live with an electrode permanently lodged in their brains. The probe is connected through wires under the skin (beneath the scalp, neck and upper chest) to a replaceable battery unit implanted beneath the collarbone. The device works something like a cardiac pacemaker, sending a steady current of electricity to a specific region deep in the brain.

The treatment works by virtue of the fact that the brain is like a complex electrical circuit. Neurological disorders can result when these electrical impulses are not working properly. When a current is applied to the right spot, surgeons can compensate for the part of the brain exhibiting problems.

DBS has also been used to treat Parkinson's disease and major depression.

Read the entire study at The Lancet medical journal.

Images: Top via Libra DBS; inset via brainstim.psy.utexas.edu.

Some earthquakes are so powerful they can actually be felt up in space. Looking to take advantage of this phenomenon, a group of researchers have created the world's first seismometer in orbit around the Earth. Well, to be more accurate, they're re-purposing a satellite originally designed to measure gravity fields on our planet's surface. It's likely a precursor to more powerful space-based stations that will help geologists monitor earthquakes — and even covert nuclear tests — as they happen.

It's called the Gravity Field and Steady-State Ocean Circulation Explorer (GOCE), and it was launched into orbit by the European Space Agency in 2009. It's equipped with a highly sensitive gravity gradiometer which detects fine density differences in the crust and oceans of the Earth. It also has six accelerometers, which is what allows it to detect seismic disturbances.

Oh, and those thrusters you see in the above image — those are QinetiQ T5 ion thrusters that can be employed to adjust its orientation in low Earth orbit.

GOCE has been used to probe hazardous volcanic regions and changing ocean conditions. And in fact, along with other satellite altimeters, it has been able to use its gravity-sniffing capabilities to measure sea surface height, which helps geologists and oceanographers track the direction and speed of geostrophic ocean currents.

But back in 2011, GOCE's monitoring team noticed that the satellite was able to detect the Tohoku earthquake in Japan. Essentially, the quake turned our planet into a giant subwoofer. The Earth was rung like a bell, causing it to transmit extreme low frequency subsonic seismic waves through the air and right into space.

Nature's Jon Cartwright explains more:

During the Tohoku quake and the resultant tsunami - which together led to some 15,000 deaths - various instruments, including Global Positioning System satellites, detected ripples propagating in the electrons of the ionosphere, a layer of electrons and ions that overlaps with the ordinary, electrically neutral part of the atmosphere between 80–600 kilometres above Earth's surface.

The effect, picked up through delays in radio signals, suggested that the electrons were being pushed around by the neighbouring ions, which in turn were propagating an infrasound wave from the neutral atmosphere below...

..GOCE detected an acoustic wave of frequency 14 millihertz (mHz) about half an hour after the quake, and another at 6 mHz about an hour after. In effect, the detection makes GOCE the first orbiting seismometer.

In future, GOCE (or similar satellites) will monitor for earthquakes in remote places (like the middle of the ocean) and scan for nuclear tests (though a magnitude 3 may be quite difficult to detect). And indeed, only time will tell if GOCE will be able to pick up more subtle earthquake events than the one that struck Japan.

Read the entire study at Geophysical Research Letters.

Sources: Nature, Dvice.

Top image: ESA/AOES MEDIALAB.

In January we reported on the successful initiative by government scientists in the U.S. to end most research done on chimps. In all, about 450 chimps currently held in government research facilities will be retired from active duty and relocated to federal sanctuaries, including Chimp Haven in Louisiana. It's going to take time — but as this video shows, it's a process that's already under way. Watch as these chimps — many of whom have never left the lab — cautiously venture outside to gaze at the wide expanse that's set before them.

To date, 111 chimps have been retired, the largest group to ever be released from experimental lab work. And as the footage shows, it's not going to be easy for some of the chimps to adapt to a new environment and new social arrangements. Some may even have to be put on anti-depressants as a way to kickstart their road to psychological recovery.

H/t PopSci.

About a century ago, astronomers discovered a fast-moving star formally known as HD 140283. Initial estimates of its age placed it a perplexing 16 billion years old — a serious problem considering that the universe is 13.8 billion years old. But a recent analysis of this so-called Methuselah Star has re-dated it to 14.5 billion years old, give or take about 0.8 billion years. Given this margin for error, astronomers are now slightly more confident that its age is compatible with that of the universe.

Using data from the Hubble Space Telescope, astronomers now have a better handle on Methuselah. It's located in our own galaxy about 190 light-years away and it's zipping past at about 800,000 mph relative to our solar system; it was likely spawned in a dwarf galaxy that was consumed by the Milky Way more than 12 billion years ago.

Astronomers were able to reduce the uncertainty of its age by using trigonometric parallax, a shift in the position of a star that's caused by a change in an observer's position. Once the astronomers had a more precise sense of its distance, they were subsequently able to measure its intrinsic brightness. This in turn allowed them to posit a more accurate estimate of its age.

From NASA:

With a better handle on the star's brightness [Howard] Bond's team [at Pennsylvania State University] refined the star's age by applying contemporary theories about the star's burn rate, chemical abundances, and internal structure. New ideas are that leftover helium diffuses deeper into the core and so the star has less hydrogen to burn via nuclear fusion. This means it uses fuel faster and that correspondingly lowers the age.

Also, the star has a higher than predicted oxygen-to-iron ratio, and this too lowers the age. Bond thinks that further oxygen measurement could reduce the star's age even more, because the star would have formed at a slightly later time when the universe was richer in oxygen abundance. Lowering the upper age limit would make the star unequivocally younger than the universe.

In their study, the authors write:

Within the errors, the age of HD 140283 does not conflict with the age of the Universe, 13.77 ± 0.06 Gyr, based on the microwave background and Hubble constant, but it must have formed soon after the big bang.

Interestingly, the star's elongated orbit is a remnant of the time it was ejected from its original galaxy. Given its speed, Methuselah is just passing by. Every 1,500 years or so, it traverses a distance in our field of vision about the width of the moon.

Read the entire study at Astrophysical Journal Letters.

Image: Digitized Sky Survey (DSS), STScI/AURA, Palomar/Caltech, and UKSTU/AAO.

One of the more extraordinary things about the universe is that it has produced beings who can observe it — namely, us. Its laws and constants are so precise that, if they were even slightly modified, no human would be here to see it. Many cosmologists and philosophers have wondered if we should read anything into all this preciseness: Are the finely-tuned physical laws that surround us mere coincidence, or does it imply that we are somehow meant to be here? That's where the Anthropic Principle comes into play.

Top image via Luc Perrot.

The Anthropic Principle (AP) is that hazy grey area where philosophy meets science. And in fact, many scientists loathe it for this very reason. It's untestable, they argue, and tautological — a skewed form of reasoning in which the principle is basically being used to prove itself.

And indeed, the AP does seem like a strange concept at first. It essentially states that we will only find ourselves in a universe that's capable of giving rise to us. Put another way, observations of the universe must be compatible with the conscious life that observes it.

It's a principle that makes perfect sense — and for some, no sense at all. But like so many things in science and philosophy, the devil is in the details.

The AP forces us to take a giant step back and evaluate the conditions of the universe in consideration of our presence within it. For scientists, it's a kind of ‘40 foot perspective' that can help illuminate — and even possibly explain — some of the more surprising aspects of cosmology. And at the very least, it serves as a constant reality check to remind us that we will always be subject to observational selectional effects; no matter where we go, we will always be there.

A good thought experiment in this regard comes from the Canadian philosopher John Leslie. In his book, Universes, he asks us to imagine a man facing a firing squad of fifty expert marksman. After aiming and firing, the executioners miss their mark.

Now, there are two ways in which we can evaluate this surprising outcome. We can either shrug our shoulders and point to the obvious, that they they simply missed. Or we can come up with some explanations as to why they all missed. This latter point is very much at the heart of anthropic reasoning.

Origins

The AP has been around for quite some time, though it only really took on its modern form in the last forty years.

Early efforts to come to grips with observational effects were expressed in Hume's Dialogues Concerning Natural Religion, and Kant's ideas about how our experience of the world is formulated by our sensory and intellectual faculties. Back in the 1920s, James Jeans observed that, "the physical conditions under which life is possible form only a tiny fraction of the range of physical conditions which prevail in the universe as a whole." Likewise, his contemporary, Arthur Eddington, speculated about "selective subjectivism," the idea that the laws of nature are indirectly imposed by the human mind, which in turn determines (and constrains) what we know about the universe.

More recently, some scientists have used it to explain the series of bizarre "large-number coincidences" in physics and cosmology. These are the surprisingly large order-of-magnitude connections that exist between (apparently) unrelated physical constants and cosmological parameters.

For example, the electromagnetic force is 39 orders of magnitude stronger than gravity. If it was any closer in strength, stars would have collapsed long before life could emerge. Or, the universe's vacuum energy density is about 120 orders of magnitude lower than some theoretical estimates, which, if any higher, would have blown the universe apart. And the neutron is heavier than the proton — but not so heavy that neutrons cannot be bound in nuclei where conservation of energy prevents the neutrons from decaying. Without neutrons, we wouldn't have the heavier elements needed for building complex life. There are many other examples, each one pointing to extreme specificity.

In 1961, Robert. H. Dickie used a prototypical version of the AP to explain away these coincidences, saying that physicists were reading too much into it. These large numbers, he argued, are a necessary coincidence (or prerequisite) for the presence of intelligent beings. If these parameters were not so, life would not have arisen. And in turn, we wouldn't be here to marvel at the ‘surprisingness' of these physical constants and laws.

Enter Brandon Carter

Then, in 1974, the philosopher Brandon Carter kindled the modern interpretation of these ideas, what he dubbed the Anthropic Principle. But rather than settle on just one perspective or definition, he said there were two different ways we can approach the issue.

Specifically, he proposed the Weak Anthropic Principle (WAP) and the Strong Anthropic Principle (SAP). Both approaches imply that these anthropic coincidences were not the result of chance, but were instead built directly into the structure of the universe.

Of the WAP he said:

We must be prepared to take into account the fact that our location in the universe is necessarily privileged to the extent of being compatible with our existence as observers.

And of the SAP he said:

The universe (and hence the fundamental parameters on which it depends) must
be such as to admit the creation of observers within it at some stage.

Indeed, the SAP is a bit of a mind frak. Carter essentially argued that, if the SAP is true, the universe must to give rise to intelligent observers. The WAP, on the other hand, simply implies that the universe we observe must have the conditions to support intelligent life, but that life doesn't necessarily have to arise.

So, if the SAP is true, then the universe is indeed here for us.

Keep in mind that these are philosophical thought experiments, and not scientific statements per se. To a certain extent, philosophers are the conjurors of proto-scientific concepts — musings that should in turn be proven or disproven through the application of the scientific method.

Moreover, this doesn't imply or prove that God or some other Prime Mover exists, though many have taken it to that extreme. All the AP does in this regard is tell us that the laws of the universe should be understood through the context of the presence of observers.

Interestingly, Carter later regretted using the word ‘anthropic.' It has misled some into thinking that he was referring to Homo sapiens specifically (or that observers were limited to carbon based life). But his principle applies to any observer anywhere in the universe.

For example, a dolphin, which is a conscious being, can be considered an observer. Same goes for a self-aware robot on the other side of the universe. Or more conceptually, imagine a universe in which only evolving streams of information can exist. Eventually, a self-aware algorithm could emerge that's capable of assessing its surroundings. This would be an observer, too, but one far removed from our own experience.

Image at left: "Wonder - Zena Gazing at the Moon" by Alex Grey (1996) .

Since Carter's original elucidation, the AP has literally been re-interpreted and re-defined hundreds of times. Other proposed names include "self-locating belief" and "indexical information" (not difficult to see why these didn't catch on). The "fine-tuning argument", however, has gained traction as a kind of substitute term, or correlated area of inquiry.

One of the more interesting re-evaluations of Carter's original idea comes from the mathematician John Barrow and physicist Frank Tipler. They devised a third principle, the Final Anthropic Principle, which states that intelligent information processing must come into evidence in the universe, and, once it comes into existence, it will never die out.

If this is true, not only is the universe here for us, but its configuration is such that we will become its permanent residents (in some form or another).

Welcome to the multiverse

As noted, many scientists hate the AP — and often with a passion. Critics contend that it's a product of cyclical thinking, and that's its self-evident — or that life should be simply be thought of as mere epiphenomenon (our presence in the universe is merely a side-effect, or coincidence).

Others, like physicist Lee Smolin, argue that the characteristics of the universe can be explained in other ways, such as his theory of cosmological natural selection. As Smolin told io9, "The Anthropic Principle is simply incapable of making a falsifiable prediction for any kind of testable experiment."

At the same time, however, scientists like Sir Martin Rees have found it to be quite helpful, particularly when applying Carter's WAP to some modern interpretations of cosmology. In fact, some physicists, like Rees, use it when explaining (and reconciling) the multiverse theory.

According to this theory, our universe is not the only one, and also not the only kind. Given the possibility of a near infinite set of variable universes, there could be alternative universes out there with different constants and parameters. In some universes, gravity will be stronger, or the speed of light slower, and so on.

In the space of all possible universes, therefore, there will be a small subset of universes in which life can exist, and a larger subset in which life is impossible. Clearly, we find ourselves in one of the life-friendly universes. Other life-friendly universes with slightly different laws, or alternative modalities, may allow for other types of observers, but observers nonetheless; they too will be subject to the anthropic effect.

On the other hand, universes that are unfriendly to life can never be observed — but that doesn't mean they're not out there. It's just that nobody will be able to document such universes and record their unique characteristics. Unless, of course, as some interpretations of quantum physics suggests, universes can only exist in the presence of observers; no observer, no universe.

The inescapable observation selection effect

Critics and proponents aside, there's one last aspect to the AP that needs to be brought out — and that's its role as an observational principle.

Tautology or not, and regardless of whether multiverses exist, it highlights a fundamental problem or limitation that all scientists face when they're making any kind of proclamation about the nature of the cosmos — and that is, as observers, we will always be subject to observational selection effects.

Consequently, it serves as a kind of reality check, one that's somewhat akin to a soft interpretation of the Heisenberg Uncertainty Principle, or even Plato's Cave. It's the oppressive realization that everything we observe is being observed. And that in order for it be be observed by that something, the environment has to be conducive for that something to exist. We can only take measurements and formulate judgements in a modality in which that can happen.

As Oxford philosopher Nick Bostrom has said, "all observations require the existence of an appropriately positioned observer." Indeed, our data is not only filtered by the limitations of our instruments, "but also by the precondition that somebody be there to ‘have' the data yielded by the instruments (and to build the instruments in the first place)." The biases that occur due to these preconditions are what's referred to as observation selection effects.

So, in answer to the headline of this article — is this universe here just for us — the Anthropic Principle alone cannot provide the answer. But it does force us to take pause and acknowledge the efficacy of the suggestion. Whether science can now run with it and provide us with an answer is an open question.

In the meantime, take solace in the fact that you're a piece of the universe that's observing itself.

Sources not cited: Anthropic Bias and "The Origin of the Modern Anthropic Principle."

Images: Ase/shutterstock, galaxy/dna: physics.sfsu.edu, "Unraveling the Riddle of Plato's Cave."

Earlier this week we reported on the remarkable news that a Mississippi-born baby was cured of HIV. Now, as if to show the disease that it's days are truly numbered, researchers from Washington University School of Medicine in St. Louis have shown that nanoparticles infused with a toxic bee venom can kill HIV. The researchers hope to take this new compound and develop a vaginal gel that can prevent the further spread of the disease.

The key to this discovery, which was made by Samuel A. Wickline and his team at Washington University, involves cytolyic melittin peptides. Melittin is found in bee venom, and it has the fortuitous trait of being able to degrade the protective envelope that surrounds HIV.

For the experiment, Wickline's team prepared free melittin and melittin-loaded nanoparticles and set them against various strains of HIV (CXCR4 and CCR5 in particular). The researchers then showed that melittin, when delivered in these large and free accumulations, can make life miserable for the disease.

Moreover, these melittin-loaded nanoparticles left the surrounding cells unharmed, which bodes well for the development of a topical vaginal virucide. But this didn't happen by accident. The nanoparticles were endowed with a kind of filter that prevents healthy cells from coming into contact with the toxin. HIV, on the other hand, is small and it sifts through these filters, thus exposing it to the toxin.

Unlike other approaches, which work to prevent HIV from replicating, Wickline's technique involves the degradation of the virus's structure.

"We are attacking an inherent physical property of HIV," said Joshua L. Hood through a university statement, and a co-author of the study. "Theoretically, there isn't any way for the virus to adapt to that. The virus has to have a protective coat, a double-layered membrane that covers the virus."

Interestingly, the concept behind the melittin nanoparticle approach could conceivably work against other diseases, including hepatitis B and C.

Eventually, the topical gel could be combined with a spermicidal contraceptive and act as a kind of two-in-one double-whammy. But for now, the researchers say that the nanoparticles are safe for sperm, and will initially be intended for couples who are trying to conceive.

And as for the study itself, it's the first proof-of-concept that the therapeutic and safe application of a nanoparticle-mediated compound can combat HIV-1.

Supplementary source: Washington University.

You can read the entire study in Antiviral Therapy.

Top image: Craig Taylor/Shutterstock; inset image: Joshua L. Hood.

For the past several weeks we've been anxiously awaiting news from the Russian research team that recently drilled into Lake Vostok, a massive body of water that's located about 2 miles below the Antarctic surface — and possibly cut off from the world for millions of years. Now, according to Russian news site RIA Novosti, a preliminary examination of water samples has uncovered bacterial DNA that doesn't appear to belong to any known subkingdom. The researchers are calling it "unidentified" and "unclassified" life.

The research team, which includes Sergei Bulat from the Laboratory of Eukaryote Genetics at the St. Petersburg Nuclear Physics Institute, cautions that tests are still ongoing, but that they're "unlikely to disprove the results."

The samples were extracted this past January 10th from a depth of 3,600 meters.

RIA Novosti writes:

"After excluding all known contaminants…we discovered bacterial DNA that does not match any known species listed in global databanks. We call it unidentified and 'unclassified' life," Bulat said.

Seven samples of the same species of bacteria were found in water frozen on the head of the drill that was used in 2012 to reach the lake, covered by a 3.5-kilometer-thick ice sheet, but the match between its DNA and any known organisms never exceeded 86 percent, while a match of under 90 percent is already enough to indicate a new species, Bulat said.

Attempts to build a phylogenetic tree for the newly discovered microorganism, which indicates a species' evolutionary relationship to other species, showed that the Antarctic bacterium did not fit any of the main categories of microorganisms in its taxonomic domain.

"If it were found on Mars, people would call it Martian DNA. But this is DNA from Earth," Bulat said.

Writing in SciAm, Caleb Scharf expresses some cautious optimism:

While the technical details are not yet available it seems that when the scientists...compared this DNA to a database of known species they found no clear match. The closest they could come was about 86% similarity, which is far enough off to suggest a new species.

Obviously we'll need to wait to see the details. Phrases like ‘bacterial DNA' are pretty vague – are they looking at things like the ubiquitous 16s rRNA, or some other sequence selections typically used for metagenomic analysis? Do they have cells under a microscope?

It looks to be exciting news though. Decades of hard work to reach one of the most alien places on Earth may actually be revealing lifeforms we have not knowingly encountered before. It doesn't really get better than this!

We'll keep you posted as new information emerges.

Photographer Bruce W. Berry has meticulously pieced together a gorgeous and humbling compilation of time-lapse sequences taken by astronauts aboard the International Space Station.

To make it happen, Berry color graded, denoised, deflickered, slowed down, and stabilized the pre-existing images. The clips were then compiled and converted to 1080 HD at 24 frames/second.

Berry was kind enough to provide a list of shots:

Footage Note: The slower video represents a closer resemblance to the true speed of the International Space Station; this footage was shot at one frame per second. Clips are all marked with an *.

Locations of Footage in the order they appear:

1. A Jump over the Terminator

2. Sarychev Volcano

3. From Turkey to Iran*

4. Hurricane Irene Hits the US

5. Indian Ocean to Pacific Ocean Through the Cupola*

6. Central Great Plains at Night*

7. Aurora Borealis over the North Atlantic Ocean*

8. Aurora Borealis from Central U.S.*

9. Up the East Coast of North America*

10. Myanmar to Malaysia*

11. Western Europe to Central India

12. Middle East to the South Pacific Ocean

13. Aurora Borealis over Europe*

14. City Lights over Middle East*

15. European City Lights*

16. Northwest coast of United States to Central South America at Night

17. Moonglow over Canada and Northern U.S.*

18. Stars from the Pacific Ocean (1)

19. Stars from the Pacific Ocean (2)

20. Stars from the Pacific Ocean (3)

21. Stars and the Milky Way over the Atlantic*

22. The Milky Way and Storms over Africa (1)

23. The Milky Way and Storms over Africa (2)

h/t fstoppers.

I'm actually planning on it.

A recent experiment in Japan shows that some of our most private thoughts may be more accessible than previously assumed. By hooking up volunteers to brain scanners, and then correlating accounts of their dreams to visual images, researchers have developed a brain decoding technique allowing them to predict broad categories of people's dreams with up to 60% accuracy.

For the experiment, three volunteers were asked to take naps inside an fMRI scanner. The researchers, a team led by Yuki Kamitani from the ATR Computational Neuroscience Lab in Kyoto, then monitored their brain activity, looking for signs that a dream state had been entered into. Once it appeared that the participants were dreaming, they were woken up and asked to describe their visual experiences.

The Telegraph explains more:

After gathering around 200 dream reports from each subject, repeated elements such as ''tree'' or ''man'' were grouped into roughly 20 broad categories. These were tailored to each participant. In one case, ''ice pick'', ''key'' and ''plunger'' were all placed in the category ''implement''.

Recordings from the fMRI brain scans were examined for activity patterns that coincided with the dream categories. Volunteers were also asked to look at photos from the internet corresponding to their dreams while their brain activity was monitored.

The data were used to train a computer programme to recognise the brain activity ''signatures'' associated with different types of dream image, while weeding out non-visual brain activity during sleep.

In a second round of dreaming, the programme successfully predicted what kind of images each volunteer was dreaming about with 60 per cent accuracy.

The system is far from perfect, and as noted, it can only predict visualizations from a broad set of categories; decoding the finer content of dreams is still not possible. But that said, it did a remarkably good job — one better than chance — at predicting, say, whether the volunteer was dreaming about a person or an apartment building.

Read the entire study at Science.

Image: Shutterstock/vgstudio.

No two people are alike, due to the subtly different ways our genomes are expressed. But sometimes these biological differences lead to genetic mutations that are extremely rare, and sometimes debilitating. Historically, many people suffering from these mutations were labeled monsters or freaks — but today, we know they are simply part of the broad spectrum of genetic variations in our species. Here are 10 of the most unusual genetic mutations we've identified in humans.

1. Progeria

This genetic disorder is as rare as it is severe. The classic form of the disease, called Hutchinson-Gilford Progeria, causes accelerated aging.

Most children who have progeria essentially die of age-related diseases around the age of 13, but some can live into their 20s. Death is typically caused by a heart attack or stroke. It affects as few as one per eight million live births.

The disease is caused by a mutation in the LMNA gene, a protein that provides support to the cell nucleus. Other symptoms of progeria include rigid (sclerotic) skin, full body baldness (alopecia), bone abnormalities, growth impairment, and a characteristic “sculptured” nasal tip.

Progeria is of great interest to gerontologists who hope connect genetic factors to the aging process. Image: HBO.

2. Uner Tan Syndrome

Uner Tan syndrome is a somewhat controversial condition, whose most obvious property is that people who suffer from it walk on all fours. UTS is a syndrome that was proposed by the Turkish evolutionary biologist Üner Tan after studying five members of the Ulaş family in rural Turkey. These individuals walk with a quadrupedal locomotion, use primitive speech, and have a congenital brain impairment (including “disturbed conscious experience”). The family was featured in a 2006 BBC2 documentary called, "The Family That Walks On All Fours." Tan describes it like this:

The genetic nature of this syndrome suggests a backward stage in human evolution, which is most probably caused by a genetic mutation, rendering, in turn, the transition from quadrupedality to bipedality. This would then be consistent with theories of punctuated evolution.

The new syndrome, says Tan, “may be used as a live model for human evolution.” Some experts think this is bunk, and that genetics may have very little to do with it.

3. Hypertrichosis

Hypertrichosis is also called “werewolf syndrome” or Ambras syndrome, and it affects as few as one in a billion people; and in fact, only 50 cases have been documented since the Middle Ages.

People with hypertrichosis have excessive hair on the shoulders, face, and ears. Studies have implicated it to a rearrangement of chromosome 8. It happens due to a disruption of the “crosstalk” between the epidermis and the dermis as hair follicles form in the 3-month fetus at the eyebrows and down to the toes. Normally, signals from the dermis send the messages to form follicles. As a follicle forms, it sends signals to prevent the area around it from also becoming a follicle, which results in the equal spacing of our five million or so follicles. Most of our body parts ignore the messages to form follicles, which explains why most of us are relatively hairless.

4. Epidermodysplasia Verruciformis

Epidermodysplasia verruciformis is an extremely rare disorder that makes people prone to widespread human papillomavirus (HPV) infection. This infection causes scaly macules and papules (cutaneous squamous cell carcinomas) to grow on the hands, feet, and even face. These skin “eruptions” appear as wart-like lesions — and even wood-like and horn-like growths — with reddish-brown pigmented plaques. Typically, the skin tumors start to emerge in people between the age of 20 and 40, and the growths tend to appear on areas exposed to the sun. Also called Lewandowsky-Lutz dysplasia, there is no known cure, though treatments to scale back the growths are possible.

The disorder was brought to the public’s attention in November 2007 when a video of a 34-year-old Indonesian man named Dede Koswara appeared on the internet. In 2008, he underwent surgery to have 13 pounds (6 kg) of the warts removed. After the lesions and horns were extracted from his hands, head, torso, and feet, his hands were grafted with new skin. In all, about 95% of the warts were removed.

5. Severe Combined Immunodeficiency Disorder (SCID)

Also known as the Boy in the Bubble Disease, it’s a disorder in which individuals are born without an effective immune system.

The disease was made famous by virtue of the 1976 film, The Boy in the Plastic Bubble, a story inspired by the lives of David Vetter and Ted deVita. In the movie, a boy is forced to live in plastic isolation for fear of exposure to unfiltered air and the introduction of life-threatening pathogens. In real life, Vetter lived in this condition for 13 years, but he died in 1984 following an unsuccessful bone marrow transplant (a failed attempt to help him fight infections).

And indeed, the disorder is caused by a number of genes, including those that cause defects in both T and B cell responses — which has a downstream negative effect on the production of lymphocytes (a type of white blood cell). SCID is also thought to arise due to the lack of adenosine deaminase (ADA). Interestingly, SCID was the first human illness treated by human gene therapy in 1990, and is increasingly being used to treat children. Image: Baylor College of Medicine Archives.

6. Lesch–Nyhan Syndrome

LNS is a genetic disorder that affects one in every 380,000 births, nearly all of them boys. It results in an overproduction of uric acid — a waste product of normal chemical processes that’s found in blood and urine. But individuals with Lesch-Nyhan release excess uric acid through their blood which builds up under the skin causing gouty arthritis. It can also cause kidney and bladder stones.

The disease also affects neurological function and behavior. Individuals exhibit involuntary body movements, like tensing muscles, jerking movements, and flailing limbs. Self-mutilating behaviors are also common, including head banging, and lip and finger biting. Individuals can be given allopurinol to help with the gout, but treatments for the neurological and behavioral aspects of the disease remain out of reach.

7. Ectrodactyly

Formerly known as “lobster claw hand, ”individuals with this disorder have a cleft where the middle finger or toe should be. These split-hand/split-foot malformations are rare limb deformities which can manifest in any number of ways, including cases including only the thumb and one finger (typically the little finger or little finger). It’s also associated with hearing loss. Genetically speaking, it’s caused by several factors, including deletions, translocations, and inversions in chromosome 7.

A 2007 ABC article featured Bree Walker, a television anchorwoman living in Los Angeles who lives with the disease. Walker also appeared on the television show “Nip/Tuck” as a character with ectrodactyly who helps a family with the disorder. Thankfully, surgical procedures can correct some of these malformations.

8. Proteus Syndrome

In conjunction with neurofibromatosis type I, this is the disease that likely afflicted Joseph Merrick, the so-called Elephant Man. It’s a condition in which bones, skin, and other tissues are overgrown. Individuals typically have organs and tissues that grow out of proportion with the rest of their body, and because the overgrowth varies and exhibits no apparent order, it can result in strange and imbalanced features. Signs of the disorder don’t usually appear until about 6 to 18 months after birth. The severity of proteus syndrome varies from individual to individual, and it occurs in less than one in one million people. And in fact, only a few hundred documented cases have ever been reported.

The disorder results from a mutation in the AKT1 gene (which regulates cell growth), causing mosaicism; as cells grow and divide, some cells exhibit the mutation while others do not. The resulting mixture of normal and abnormal cells is what causes the overgrowth.

9. Trimethylaminuria

This genetic disorder is so rare that its rate of incidence is not even known. But it’s very obvious when someone with trimethylaminuria is standing next to you. Individuals with the condition, because they cannot break down the naturally occurring — but pungent smelling — trimethylamine, literally smell like rotting fish, rotting eggs, garbage, or urine. It’s for this reason that it’s also called the Fish Odor Syndrome. Trimethylaminuria is found in sweat, urine, exhaled breath, and other bodily secretions. But for individuals with this disorder, typically women (for unknown reasons) it shows up in abnormal amounts. The severity of the odors seem to peak just before and during menstrual periods and after taking oral contraceptives; there may be a link to female sex hormones like progesterone or estrogen.

Consequently, people with trimethylaminuria have an exceptionally difficult time in social settings. The odor can vary in intensity over time, but many people experience depression and social isolation as a result.

10. Marfan Syndrome

While unusual in its manifestations, this genetic disease is fairly common. Marfan syndrome is a disorder of the connective tissues, and it appears in about one in every 10,000 to 20,000 births. Interestingly, nearsightedness (or myopia), is a common form of the disease. But it’s more renowned for the way it causes bones to overgrow and create loose joints. People with Marfan Syndrome tend to have long and thin arms and legs. Overgrown ribs can cause the chest bone to bend inward or push outward. Spinal curvature is another problem.

It’s a myth, by the way, that Lincoln had it (he probably had Multiple endocrine neoplasia type 2B). But other famous people with Marfan include Sergei Rachmaninoff, Robert Johnson, and Bradford Cox of Deerhunter/Atlas Sound fame (featured in image at left). Javier Botet, the actor who recently spooked audiences as the bendy ghost in Mama, also has Marfan syndrome.

Top illustration by appler via Shutterstock

This was a tough one to research. I have to admit that I got queasy at times.

Fair point — and that's actually a great idea for a future list.

Awesome! Thanks for replying.

The death toll from a new flu strain in China has now reached six. It's not known if the virus can be transmitted from person to person, but based on what the experts are saying, it’s a development that needs to be taken very seriously.

The first report to come in that the new avian influenza, H7N9, could infect humans arrived in February of this year. Now, six deaths later, officials in China are scrambling to contain it. No less than 16 people have now been infected by it, some of them in critical condition. Of those infected, it's not known how 11 contracted it.

As of today, this is the situation among those infected:

And the apparent rate of spread:

Charts via ECDC.

In turn, Shanghai officials have closed the Hauhau agricultural market and the slaughtering of birds has begun; as of today, more than 20,000 birds have already been killed. Starting this coming April 6, Shanghai will suspend all trade of live poultry.

Situation as of April 5, 2013; via ECDC.

According to the World Health Organization, symptoms include fever, cough, and shortness of breath, leading to severe pneumonia. But in reality, precious little is known about the new strain. The virus is suspected of jumping from birds to humans, but no evidence exists that it’s transmissible from human to human. Consequently, experts are telling people to not be alarmed.

That said, scientists who have worked on the virus say a recent mutation may now allow it to move more easily from animal to animal, which could pose a heightened risk to humans. On April 4, the Center for Disease Control starting sequencing H7N9 in hopes of developing a vaccine.

Disturbingly, the new virus is harder to detect than the H5N1 virus. The new strain can infect birds without causing the disease; it produces few, if any symptoms in some birds.

One person who’s particularly worried about H7N9 is Foreign Policy’s Laurie Garrett. In particular, she’s worried that the virus is also making the rounds in the pig population.

She writes:

Influenzas are named according to the specific nature of two proteins found on the virus — the H stands for hemaggluntinin and the N for neuraminidase. These proteins play various roles in the flu-infection process, including latching onto receptors on the outside of the cells of animals to transmit the virus into their bodies. Those receptors can vary widely from one species to another, which is why most types of influenza viruses spreading now around the world are harmless to human beings. As far as any scientists know, the H7N9 forms of flu have never previously managed to infect human beings, or any mammals — it is a class of the virus found exclusively in birds. It is therefore extremely worrying to find two people killed and one barely surviving due to H7N9 infection. [Garrett wrote this prior to learning about the new deaths]

One very plausible explanation for this chain of Chinese events is that the H7N9 virus has undergone a mutation — perhaps among spring migrating birds around Lake Qinghai. The mutation rendered the virus lethal for domestic ducks and swans. Because many Chinese farmers raise both pigs and ducks, the animals can share water supplies and be in fighting proximity over food — the spread of flu from ducks to pigs, transforming avian flu into swine flu, has occurred many times. Once influenza adapts to pig cells, it is often possible for the virus to take human-transmissible form. That's precisely what happened in 2009 with the H1N1 swine flu, which spread around the world in a massive, but thankfully not terribly virulent, pandemic.

If the pigs, people, and birds have died in China from H7N9, it is imperative and urgent that the biological connection be made, and extensive research be done to determine how widespread human infection may be. Shanghai health authorities have tested dozens of people known to have been in contact with Wu and Li, none of whom have come up positive for H7N9 infection. Assuming the tests are accurate, the mystery of Li and Wu's infections only deepens. Moreover, if they are a "two of three," meaning two dead, of three known cases, the H7N9 virus is very virulent.

Hong Kong authorities are not taking any chances, and they’ve put the area on alert. Some hospitals in mainland China have also been put on high alert.

Sources: CBC, Washington Post, AP, Foreign Policy.

Looks like BigDog finally has a robotic counterpart to take him out for a walk. Actually, Boston Dynamics's PETMAN has been under development for a while now, but this is our first opportunity to see him decked out in full battle gear.

The DoD funded Boston Dynamics says the humanoid robot is being used to test the performance of protective clothing designed for hazardous environments. PETMAN has sensors embedded in its skin to detect any chemicals that might leak through the suit. The skin can also maintain a micro-climate inside the suit by sweating and regulating temperature.

I was surprised by how much this made my stomach turn when I first watched it. It's the uncanny valley aspect to it, I think. There's a threatening quality to it, another reminder of how we're inexorably headed towards the creation of a true humanoid robot.

Having a strong opinion about an issue can make it hard to take in new information about it, or to consider other options when they're presented. Thankfully, there’s an old rule that can help us avoid this problem — and even help us make good decisions when we’re uncertain. Here’s how Bayesian Reasoning works, and why it can make you a better thinker.

To find out more about this topic, we spoke to mathematician Spencer Greenberg, co-founder of Rebellion Research and a contributing member of AskAMathematician where he answers questions on math and physics. He has also created a free Bayesian thinking module that's available online.

Bayes’ Rule is derived from a mathematical formula, but as we learned from Greenberg, you don’t need to know the equation or do fancy math to apply Bayes’s principle to daily life.

“It’s usually not that useful writing out Bayes’s equation,” he told io9. “And in fact, in order for this line of thinking to be useful in day to day life, you have to be able to think about it without having to sit down and write out a formula.” Fortunately, says Greenberg, there is a way to do that.

The Power of Probabilistic Reasoning

Bayes’s Rule is a theorem in probability theory that answers the question, "When you encounter new information, how much should it change your confidence in a belief?" It’s essentially about making decisions under uncertainty, and how we should update or revise our theories as new evidence emerges. It can also be used to help us reach decisions in those circumstances when very few observations or pieces of evidence are available. And it can also be used to help us avoid common mistakes and fallacies in our thinking.

Bayesianism is a great example of math applied to daily life. It’s derived from a widely accepted and uncontroversial formula that’s been around for hundreds of years.

“But it gets philosophically interesting when you start to interpret its implications,” says Greenberg.

The 18th century mathematician and theologian Thomas Bayes came up with the formula, and it has been used in a variety of applications ever since. Today, it’s used to analyze sequences of data in such fields as finance, artificial intelligence, engineering, medicine, and philosophy.

The key to Bayesianism is in understanding the power of probabilistic reasoning. But unlike games of chance, in which there’s no ambiguity and everyone agrees on what’s going on (like the roll of die), Bayesians use probability to express their degree of belief about something.

Degrees of Belief

When it comes to the confidence we have in our beliefs — what can be expressed in terms of probability — we can’t just make up any number we want. There’s only one consistent way to handle those degrees in beliefs.

“And that’s what Bayes’s Rule tells us — it tells us that if we have a certain belief about something, and then you get some evidence, the Rule tells us how to choose that degree of belief in order to come up with a new, or updated, strength of belief.”

And this, says Greenberg, is where Bayes gets really interesting.

“When you believe something is 20% likely, and then you get a new piece of information, it can tell you whether you now should think it's 10% likely, or 40% likely — it basically tells you how to process that information.”

In the strictest sense, of course, this requires a bit of mathematical knowledge. But Greenberg says there’s still an easy way to use this principle in daily life — and one that can be converted to plain English.

“It’s not the easiest thing in the world, because we don’t make up the rules of evidence,” he says. “The rules of evidence are inherent in the ways that probability work — perhaps even in the way the universe works — so we don’t get to choose how we actually process evidence that’s given to us."

Question of Evidence

Greenberg presents us with an example, one that involves a “belief” and what he calls the “question of evidence.”

Let’s take John. John is 20% certain that his exercise routine is giving him more energy throughout the day. After he performs the exercise routine, the question emerges in his mind about the strength of that evidence. Is it high? Moderate? Weak? It’s here where Bayes can help.

Greenberg says it’s the question of evidence which he should apply, which goes like this::

Assuming that our hypothesis is true, how much more plausible, or likely, is the evidence compared to the hypothesis if it was not true?

So, John needs to ask himself: How often do I feel energetic? If he feels energetic one out of every three days each week, John can say that it’s relatively weak evidence; it’s not that much more likely that exercise will make him energetic if the belief was true than if it wasn’t true. But if he has low energy virtually every day of the year, then he can say the evidence was very strong.

“It’s important to note that the idea here is not to answer the question in a precise way — like saying that it’s 3.2 times more likely — rather, it’s to get a rough sense. Is it a high number, a modest number, or a small number?”

To make Bayes practical, we have to start with the belief of how likely something is. Then we need to ask the question of evidence, and whether or not we should increase the confidence in our beliefs by a lot, a little, and so on.

“It doesn’t mean you should change your mind necessarily,” he adds.

“Let’s say you get some evidence that might actually be legitimate evidence,” he says. “Much of the time people will automatically try to shoot down evidence, but you can get evidence for things that are not true. Just because you have evidence doesn’t mean you should change your mind. But it does mean that you should change your degree of belief.”

Greenberg argues that, given this new evidence, if you used to believe that something had a 1 in 1000 chance in being true, now, armed with the new evidence, you might think that it has a 1 in 100 chance of being true.

“You still think it’s unlikely,” says Greenberg, “just less unlikely.”

Correcting Glitches in Our Thinking

Bayesian inferencing can also help with common fallacies and errors in thinking.

A typical area in which people make mistakes is in assessing evidence, particularly when confounding it with irrelevant data, or when starting with the wrong initial belief.

Greenberg offers the example in which a cancer test is shown to be 98% accurate. The cancer in question is rare, and people have a one in a million chance of having it.

“But if you ask most people what’s the probability that you have cancer given that the test comes out positive, most people will say 98% — but they’re saying that because the test is 98% accurate,” says Greenberg. The problem, he says, is that people are starting off with the wrong initial belief. It should have been the one in a million claim. Their incorrect answer (and line of reasoning) is independent of how rare the cancer is.

Greenberg also describes Representativeness Heuristic in which people tend to look at how similar things are.

For example, we hear about a person who wears a pocket protector and is a bit nerdy — what would satisfy the stereotype of someone who is an accountant. We then ask, what is the probability that this person is an accountant? How representative is this person to our mental image of an accountant?

But as Greenberg points out, this not sufficient to make a determination.

“To get people to make the wrong judgement on tests — to get their probabilities way, way off, choose a vary rare profession,” says Greenberg, “but make it sound like something stereotypical of that profession.”

Clearly, this is a problem that feeds into stereotyping, but one that Bayes can help to remedy.

More pertinent questions would be to ask how common or rare that thing is, like accountants. He says we need to take the base rate of these traits in the population, and then ask how similar it is to the judgment you’re trying to make.

No Absolute Beliefs

Greenberg also says that we should shy away from phrases like, “I believe,” or “I don’t believe.”

“That’s the wrong way to frame it,” he says. “We should think about things in terms of how probable they are. You almost never have anything close to perfect certainty.”

‘I believe,’ or ‘I don’t believe’ are convictions that can also be very dangerous, he says.

“Let’s say you believe that your nutrition supplement works,” he told us, “Then you get a small amount of evidence against it working, and you completely write that evidence off because you say, ‘well, I still believe it works because it’s just a small amount of evidence.’ But then you get more evidence that it doesn’t work. If you were an ideal reasoner, you’d see that accumulation of evidence, and every time you get that evidence, you should believe less and less that the nutritional supplements are actually working.”

Eventually, says Greenberg, you end up tipping things so that you no longer believe. But instead, we end up never changing our mind.

Greenberg says we should use phrases like, “I think this is likely,” or “I think this is very likely.” We can “believe” things to some degree, but not to an unlimited degree.

We should also refrain from claiming to have absolute certainty. Even the smallest amount of skepticism is necessary; it’s okay to say that something is incredibly, incredibly, probable — but not that it is 100% certain.

“You should never say that you have absolute certainty, because it closes the door to being able to revise your certainty in light of new information,” Greenberg told io9. “And the same thing can be said for having zero percent certainty about something happening. If you’re at 100% certainty, then the correct way of updating is to stay at 100% forever, and no amount of evidence can tip you.”

Greenberg compares certainty to the speed of light.

"You can keep adding and adding information, getting more and more confident, but you can never get all the way to 100%,” he says. We’re dealing with finite amounts of evidence.

“There's always some chance that we've misunderstood something somewhere, or have made a reasoning error, or failed to grasp some unknown unknown, or even gone mad and don't realize it. This creates wiggle room making it hard to ever justify believing with 100% certainty. You would have to be 100% certain that you aren't making some tiny error somewhere, and 100% certain that you understand all the relevant facts, etc., which isn't attainable in practice.”

Probability Relativity

Lastly, he also says that probabilities can depend on the observer — what is a kind of probability relativity. We all have access to different information, so different people should assign different rates of probability to different things based on different sets of evidence.

For example, take the flipping of a coin. One person has seen the flip, the other person has not. The one who has seen the flip is 99.999999% certain that it’s heads because she has seen it (the slight margin for error can be attributed to a memory glitch or visual problem she may have experienced). The other person, on the other hand, has to settle for 50% certainty.

So that’s Bayes Rule. Now go out there and starting updating your beliefs as new evidence emerges!

Images: Shutterstock/Viorel Sima.