A new theory of negative mass

It was Einstein who first noted that we have two different definitions of mass.

      1. Mass is inertia.  It’s a measure of how hard it is to get something stationary to start moving or to get something that’s moving to stop.  F=ma.
      2. Mass is the source of gravity.  Mass is attracted to other mass through the weakest force in the universe.  F=Gm1m2 / R2

Einstein elevated the equivalence of gravitational and inertial mass to a founding postulate, the equivalence principle, and on it he built a geometric theory of gravity.

Jamie Farnes, an Oxford University physicist, thinks that some of the mass in the universe is negative.  It has negative gravitational mass and negative inertial mass.  So Farnes-stuff has a repulsive gravitational effect on itself, but it attracts ordinary matter.  In the Farnes universe, negative mass is being continually created, popping out of the vacuum.

What’s the motivation for making a radical new proposal?  Well, 20 years ago, cosmologists realized that the conventional view isn’t viable.  On the one hand, they found that galaxies are held together by a force stronger than their gravitational mass can account for.  On the other hand, they found that the universe is flying apart faster and faster, as if under the influence of some kind of negative gravity.  To solve these two problems, the conventional wing of physical cosmology postulated that 70% of everything in the universe is “dark energy” while 25% is “dark matter”, and only 5% is the matter we’re familiar with.  In order to explain the motions of the 5%, they have invented 95% of stuff that no human has ever seen, heard, or tasted, and that we know for a fact can’t be made of electrons, neutrons, protons, or any of the exotic particles observed in high-energy accelerators.

So Farnes-stuff is no more crazy than the theory it purports to replace, and the advantage, says Farnes, is that it’s just one thing—a single substance that can play the role of both dark matter and dark energy.

I was skeptical about dark energy and dark matter because they were invented out of the blue to rescue a failing theory.  Three hundred years ago, people invented phlogiston to account for the properties of heat, and two hundred years ago there was the luminiferous aether to explain the properties of light.  Today, we understand light and heat without the need for these fictional substances.

But I became less skeptical once I saw a video by Yale astrophysicist Priya Natarajan, describing two ways to locate dark matter in maps of the sky.  (1) she looked for gravitational lenses—concentrations of matter that bend light from distant galaxies and distort the images, or even cause them to appear in two pieces  (2) she reverse-engineered the gravity that binds galaxies together to locate the extra mass that would be needed to keep them from flying apart.  Natarajan shows pictures in which these two maps coincide.  In other words, two different ways to detect dark matter seem to agree.


The question I would like to see Natarajan and Farnes address is whether the same trick works for Farnes-stuff.  Can gravitational lensing and the coherent force in clusters of galaxies be explained in a single map of where the negative mass is hiding?



(~∃∞) = (Infinity doesn’t exist)

“Where did the Big Bang come from?  Who made it? Answer me that, wise guy!”

It would be plenty Daoist enough to imagine that the Universe popped into existence from the void.  There was nothing, and there was nothing, and there was nothing, and then there was everything.

What Einstein’s equation tells us is another leap beyond what our diminutive brains can grok.  Space-time came into existence at the moment of the Bang. We might stretch our minds to imagine existence outside of space. Existence outside of time is something else again.

∪∉t.    t∈∪

(The world does not exist in time, but time exists within the world.)

The domain of time is part of our Universe.  Another part, part of what exists, is outside of time.


Contemplation of paradox is a path to expanded awareness.  This is the logic of the illogical Zen koan. The mind that forms rational structures to house and to order its knowledge gives up, and a larger mind takes over, one that is capable of encompassing a reality beyond our senses, beyond comprehension, beyond logic.

Existence outside of time.

Time is just one domicile, one possible home for being.  Something birthed space-time, something larger, something capable of encompassing space-time as part of itself.  

Dao is beyond understanding.  Words may be used to speak of it, but they cannot contain it.

Dao existed before words and names, before heaven and earth, before the myriad things.

Therefore, to see beyond all boundaries to the subtle heart of things, dispense with names, with concepts, with expectations and ambitions and differences.

Dao and its many manifestations arise from the same source: subtle wonder within mysterious darkness.

To dwell in the world as it is, we must first dispense with the ambition to understand.

— Dao De Jing (or Tao Te Ching), Brian Browne Walker translation (all except the last line which is my own rendering)


Les Deux Infinis

Infinity as a concept has been made rigorous by mathematicians.  It is assigned a definite meaning so that the symbol ∞ can be manipulated sensibly without undermining the logic of the systems in which it participates.  Mathematicians can talk about infinity because they have come to agreement in advance about precisely what it means.

1 / 0 = ∞

In science, infinity has another meaning, a different meaning that must not be confused with mathematical infinity.  To a physicist, infinity simply means “large enough that we don’t have to worry about running out, or coming to its end.”  Alternatively, infinity is a conceptual tool for approximate calculations. We say something is infinite to justify neglecting terms that are in comparison, that might be added to it or subtracted from it.  We always remember that an infinity must be divided by a comparable infinity before it has a meaningful place in our computations or in our conceptions.  Infinity always cancels out of the equations.

The greater part of quantum field theory consists in rules for how to add and subtract infinities so that we are left with a finite answer.

Physicists acknowledge that we come to practical limits of what we can measure, or of what affects us, so we never have to grapple with mathematical infinity.  Mathematical infinities are not part of our world, not in any sense that has consequence for science.

Astronomers commonly raise the question, Is our Universe finite or infinite?  And the related question, Will the Universe go on forever, or will time come to an end?  They adduce evidence in the form of measurements of speeds and galaxy counts and densities, plug those numbers into Einstein’s equations, and purport to tell us one way or the other. These questions and their answers must be understood in the context of physical infinity, not mathematical infinity.  

Physics offers us enough challenges to stretch our mental framework without having to worry about forever, so there’s one subject on which you can set your mind at ease.

Time, even time had a beginning, and will have an end.

Go to bed

Early to bed and early to rise
Makes a man healthy, wealthy and wise
Ben FranklinMathew HenryJohn Clarke?

Science has determined that going to bed early and rising early makes you happy.  Or maybe it’s the genes that make you an early riser that make you happy.  Or maybe it’s the genes that make you go to bed early, and then going to bed early makes you happy.  It’s hard to tell these things.

IS it not better at an early hour
In its calm cell to rest the weary head,
While birds are singing and while blooms the bower,
Than sit the fire out and go starv’d to bed?

— Walter Savage Landor, born this day in 1775

Joseph Ducreux (French) - Self-Portrait, Yawning - Google Art Project.jpg


God scatters beauty as he scatters flowers____
O’er the wide earth, and tells us all are ours._
A hundred lights in every temple burn,______
And at each shrine I bend my knee in turn.__

Walter Savage Landor


Weaponized snot

A car is covered in hagfish, and slime, after an accident on Highway 101.

This car was disabled when it passed through a puddle of slime left by an overturned truck bearing hagfish to market.

The hagfish produces such copious amounts of slime that it can immobilize prey, or clog the gills of an attacking shark.

Hagfish are true fish, but of an ancient order similar to lampreys that separated from bony fishes 300 million years ago.  They look like eels, but have even more flexible bodies beneath a loose bag of skin.

Image result for hagfish

Hagfish eat by boring through the carcass of a dead fish, then absorbing nutrients through their skin.  The mouth is just a drill head.

Image result for hagfish fried

They’re a delicacy in Korea.

Article in The Atlantic

The Measure of All Things

For 99.99% of the history of the living earth, there were no human beings on its surface.  Was this world of no value, an extravagant waste because there was “no one there to appreciate it”?

And for most of the remaining 0.01%, humans had a negligible global impact on the web of life.  So, during that time, were things better or worse?

Image result for most beautiful tree

If man is the measure of all things, then it makes no sense to ask about the beauty of a biosphere on which no man opened his eyes. But if elephants can paint, then surely they have a visual aesthetic, and even human musicians recognize a beauty in the cetacean’s song. Birds decorate their nests, and spiders love symmetry. Some butterflies rival the peacock’s prodigious pulchritude, and even the bees seem to prefer a pretty flower to a plain one.

Beautiful Bee In Flower</a>

Can trees and mushrooms be unaware of their beauty?

amanita_muscaria_fly_agaric beautiful mushroom photography

We do not have to stretch far to imagine a broader sense of beauty shared by animals

Just as we are awash in numb, blind terror of impending death, though we regard the aeons of time before our birth with equanimity, so we view human extinction as the ultimate apocalypse, rather than a return to normalcy.

Estimates of the probability of near-term human extinction differ widely. Probably, the question is not subject to probabilistic analysis. But it is hardly unthinkable, for those of us with the courage to indulge in the folly of thought.

What would the brontosaurus have said if you told him that he would be succeeded by fieldmice?

Hal, tell me what you’re thinking

Computer learning systems are solving big problems.  The programmer doesn’t tell the computer how to proceed, but merely provides massive amounts of data for the computer to learn with.  The computer sets about blindly looking for patterns in the data and sometimes finds patterns that people would never see.

Examples include:

On the one hand, it’s great to to have someone who really “thinks different” looking at the data and making suggestions.  On the other hand, it’s a human being who is going to use this pattern or (formula or algorithm of diagnosis or plan) at the end of the day, and often the stakes are high.  How is the human to know that this crazy idea the computer came up with isn’t just an artifact of the data, or a programming error?

“Hal, explain yourself!”

Image result for talk to a computer


Over at Google Brain, Been Kim has worked on this problem, and now has (the beginnings of) an interface to query the computer, so we might learn not only what the computer’s solution is, but how it got there.

Survival of the Beautifulest


Darwin explained the extravagant beauty of some birds, fish and insects as providing an advantage in attracting mates.  He called it sexual selection, and he was pretty clear that the process was different from acquisition of traits that had practical use in an objective sense.  Female preferences co-evolve with male coloration.

Image result for wildflowers

It is hard to escape the conclusion that there is something wonderful here that transcends the quest for mating success.  Why is it that the peacock’s aesthetics or the butterfly’s taste for color should resonate so well with our human perceptions of what is beautiful?

This NYTimes Mag article flirts with the idea that beauty is not entirely explained by evolutionary science.

What we call beauty is not simply one thing or another, neither wholly purposeful nor entirely random, neither merely a property nor a feeling. Beauty is a dialogue between perceiver and perceived. Beauty is the world’s answer to the audacity of a flower. It is the way a bee spills across the lip of a yawning buttercup; it is the care with which a satin bowerbird selects a hibiscus bloom; it is the impulse to recreate water lilies with oil and canvas; it is the need to place roses on a grave.

Image result for butterfly coloration