Neil deGrasse Tyson in ‘The Inexplicable Universe’

If you’re enjoying the Cosmos series, you might enjoy these lectures by Neil deGrasse Tyson, which I discovered yesterday is now on Netflix.  The lectures are fairly far ranging covering things like string theory, dark matter, dark energy, gravitational anomalies, and many other things.

If you’re well read in science, a lot of this might be basic stuff, but Tyson has a way of describing things that keeps it novel and fresh.  Unlike Cosmos, this is mostly just Tyson sitting in a room talking, with an occasional visual aid interjected.  I enjoyed them enough that I watched the whole thing straight through last night.

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The flower-shaped starshade that might help us detect Earth-like planets

Pretty cool.  Jeremy Kasdin in this TED talk discusses an idea to remove the glare of a star’s light in order to possibly get a look at its planets.


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First potentially habitable Earth-sized planet confirmed by Gemini and Keck observatories — ScienceDaily

This is a pretty big milestone.  The first Earth sized planet in a star’s habitable zone.  Pity it’s so far away (500 light years) that spectral analysis probably won’t be possible to figure out what its atmosphere has in it.

The first Earth-sized exoplanet orbiting within the habitable zone of another star has been confirmed by observations with both the W. M. Keck Observatory and the Gemini Observatory. The initial discovery, made by NASA’s Kepler Space Telescope, is one of a handful of smaller planets found by Kepler and verified using large ground-based telescopes. It also confirms that Earth-sized planets do exist in the habitable zone of other stars.

via First potentially habitable Earth-sized planet confirmed by Gemini and Keck observatories — ScienceDaily.

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The Sniper – Existential Comics

The profound thoughts of a sniper.  Click through to read the whole thing.

via The Sniper – Existential Comics.


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Neanderthals and Cro-magnons did not coexist on the Iberian Peninsula, suggests re-analysis of dating — ScienceDaily

The meeting between a Neanderthal and one of the first humans, which we used to picture in our minds, did not happen on the Iberian Peninsula. That is the conclusion reached by an scientists after redoing the dating of the remains in three caves located on the route through the Pyrenees of the first beings of our species: L’Arbreda, Labeko Koba and La Viña.

more at Neanderthals and Cro-magnons did not coexist on the Iberian Peninsula, suggests re-analysis of dating — ScienceDaily.

So the cross breeding between anatomically modern humans and Neanderthals happened outside of Europe, and much earlier than the entry of modern humans into that region, most likely in the middle east based on what I’ve read.

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Tegmark’s Level III Multiverse: The many worlds interpretation of quantum mechanics


Credit: Christian Schirm via Wikipedia

Credit: Christian Schirm via Wikipedia

I recently finished reading Max Tegmark’s latest book, ‘Our Mathematical Universe‘, about his views on multiverses and the ultimate nature of reality.  This is the third in a series of posts on the concepts and views he covers in the book.  

The previous entries are:
Tegmark’s Level I Multiverse: infinite space
Tegmark’s Level II Multiverse: bubble universes

Tegmark postulates four levels of multiverse.  This post is on what he calls the Level III Multiverse, the many worlds interpretation of quantum mechanics.

In the early twentieth century, one of the mysteries of science was the constant speed of light.  The speed of light was constant no matter how it was measured.  This was in contrast to the speed of sound, or the speed of just about anything else, which varied depending on the speed of the observer.

Albert Einstein accepted the experimental evidence of the constancy of the speed of light, and explored its implications.  If the speed of light was always constant, then something else had to give.  Something that factored into that speed had to vary, something like mass, length, and time.  Exploring those implications led to the special theory of relativity.

For several decades now, one of the mysteries of science has been wave / particle duality.  We have strong evidence that light behaves like a wave, and strong evidence that it behaves like a particle.  We have similar evidence for electrons and just about any other subatomic particle, as well as atoms themselves and even large molecules under isolated conditions.

The shape of a wave is modeled in a mathematical concept called the wave function.  The particle will appear somewhere in that wave.  There is no known way to predict where in the wave any individual particle will be found.  All that can be known are probabilities of it appearing at various locations within the wave.  Bizarrely, once the position of the particle is observed, once it is measured, all trace of the overall wave instantly disappears, with only the particle remaining.

Just to be clear, this is freaky strange, and no one is certain why it is so.  Reality at the quantum level appears to be wavelike, to the degree that the wave can physically interfere with itself when split, but suddenly, instantly, becomes particle like when we look at it.  As strange as it is, this has been confirmed for decades by extensive experimental data.  It is reality.

There are a number of interpretations of what is happening.  The oldest, and for a long time the most popular, is called the Copenhagen Interpretation.  It is basically is a minimalist interpretation that says that this is simply reality, and that when a particle’s position is measured, the wave function “collapses”.  Prior to the collapse, the particle exists in what’s called a superposition.  It exists in multiple locations at the same time, but once the position is known, the existence of the particle in all but one of those locations disappears.

There are several other interpretations.  All of them must throw one or more aspects of common sense reality under the bus in order to make sense of the data.

In the 1950s, Hugh Everett came up with a new interpretation.  Everett accepted the mathematics of the wave function, but was troubled by the lack of anything in those mathematics that predicted a wave function collapse.  The only reason that the wave function collapse is thought to exist is the fact that we only observe the particle in one location once it is measured.

Everett asked, what happens if the wave function, in fact, never collapses?  If the wave function predicts two locations for the particle, then the mathematics say the particle is in both locations.  Of course, we don’t observe it to be in both locations.  So then, what’s going on?  Similar to when Einstein was contemplating the constant speed of light, something else has to give.

According to the mathematics and our sensory data, we should see the particle in only one of the locations and we should see it only in the other one.  No, the second “only” in the previous sentence is not a typo.  We appear to have two realities in which we observe the particle.  Prior to the measure, there was only one reality.  After the measure, there are two.

In multiverse parlance, the many worlds interpretation asserts that our universe is cloned every time what appears to be a wave function collapse happens.  Given that this happens an uncountable number of times per second throughout the universe, and given the large range of possibilities for each particle’s position, the number of universes being created every second is sublime.

The randomness of the particles location then is an illusion, created by the fact that we only observe the location particular to our universe.  But the wave function unfolds unabated with the particle existing in each location in a different universe.

This means that there are an uncountable numbers of you in these alternate universes, where each quantum result is manifested.  In other words, every random event that could happen, happens in some universe, and there are an uncountable versions of you living every conceivable version of your life.

In Tegmark’s framework, this is the Level III Multiverse.  It is a superset of the Level I and II multiverses, although as formulated, there’s no particular reason that its existence, or non-existence, is dependent on the other ones.  If all three levels exist, then Level III includes all the multiverses in the lower levels and reality continues to expand at an astounding rate.

Tegmark does note some similarities between the Level I and Level III multiverse.  In both, there are an infinite number of you living every possible variation of your life.  The result of every quantum possibility should be manifest in one of the Level I universes.  Of course, if they were one and the same, it would mean that remote regions in the Level I multiverse were in some way quantum entangled with each other.

Tegmark also speculates about reconciling the Level II and III multiverse, but doesn’t currently see a way to do it.

Over time, support for the many worlds interpretation has grown in the particle physics community, although Copenhagen continues to hold a plurality in most polls.  The question is, is there any way to test this idea?  Brian Greene in ‘The Hidden Reality’ identified the possibility of the uncollapsed wave interfering with itself across universes, although he notes that observing this would be extremely difficult.

Tegmark proposes another one, although it’s not one that anyone is liable to volunteer for.  The quantum suicide or subjective immortality thought experiment involves setting up a gun with a trigger set to fire if a random quantum event takes place, with a 50% chance of taking place in the first second.  The experimenter then puts their head in front of the gun.

In 50% of the universes, the experimenter dies within the first second, but in the other 50%, they live.  For each second, the probability of the experimenter being alive goes down.  After a couple of minutes, the probability of the experimenter still being alive is infinitesimal.  However, in at least some portion of the alternate universes, the experimenter lives on.

From the subjective point of view of the experimenter, the longer they live, the higher the probability of the many worlds interpretation being true.  After a few hours, increasingly unlikely events (misfire, power outage, meteor strike, etc) begin to happen to prevent their death.  If an experimenter subjectively survived this ordeal for several hours, they could have a high degree of confidence in the many worlds interpretation.  (Of course, in virtually all universes, they would leave behind grieving friends and family who would be less convinced.)

Tegmark then points out that, if either the many worlds interpretation or infinite space scenario is true, then a version of each of us will, despite its improbability, live long enough to outlast all of humanity.  In other words if is true, subjectively, you will live long enough to know it is true, at least assuming you recall reading this.  Each of us may live to be the last human in our own improbable universe, knowing the truth of the multiverse.

In the next post, we will get into the main idea of Tegmark’s book, the mathematical universe hypothesis.

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Climate Efforts Falling Short, U.N. Panel Says

In the sobering news department:

Delivering the latest stark news about climate change on Sunday, a United Nations panel warned that governments are not doing enough to avert profound risks in coming decades. But the experts found a silver lining: Not only is there still time to head off the worst, but the political will to do so seems to be rising around the world.

via Climate Efforts Falling Short, U.N. Panel Says –

And if we wait too long, take a look at some of the crazier things we might have to think about doing.

Moon mining for space dust; dumping iron filings in the sea, and creating an enormous space parasol are some of the most bizarre ideas put forward by scientists to tackle climate change

via How to save the planet: Moon mining, iron filings and fake volcanoes – Telegraph.


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