Tag Archives: Gravity

Shot in the Dark

21 September 2025 By in Physics, Science, Space Tags: , , , , , , , , , , , , , , , Leave a comment

The Earth orbits the Sun at a brisk 107,000 km/hr (66,486 mi/hr). The Sun, in turn, circles the Milky Way at a staggering 828,000 km/hr (514,495 mi/hr). And deep in the galactic core, stars whirl around the supermassive black hole at relativistic speeds, up to 36 million km/hr (22,369,363 mi/hr). Gravity is the architect and master of this motion: the invisible hand that not only initiates these velocities but binds our galaxy into a luminous spiral of unity.

Except it shouldn’t. Not with the piddling amount of mass that we can see.

The Milky Way contains 60-100 billion solar masses, an impressive sum, but a puny, gravitationally insufficient amount. With only that amount of ordinary matter, the galaxy would disperse like dry leaves in a breeze. Its stars would drift apart, its spiral arms dissolve, and the universe itself would remain a diffuse fog of light and entropy, never coalescing into structure or verse. No Halley’s Comet. No seasons. No Vivaldi.

To hold the Milky Way together at its observed rotation speeds requires about 1.4 trillion solar masses, seven times the visible amount. And we know this mass is there not because we’ve seen it, but because the galaxy exists. Much like Descartes’ Cogito, ergo sum (“I think, therefore I am”), we reason: The Milky Way is; therefore, it must possess sufficient mass.

The problem is that 85% of that mass is missing; from view, from touch, from detection. Enter stage right: Dark Matter. It does not emit, absorb, or reflect light. It does not interact with ordinary matter in any known way. It is invisible, intangible, a Platonic ether of shadow reality. Without it, the sacrament of gravity and being floats away like a balloon on a huff and puff day. And the universe loses its meaning.

Much like the neutrino, predicted by theory, is a particle once postulated to preserve the sanctity of conservation laws, a piece of the quantum world long before it was ever seen. Dark Matter is another elusive phantom, inferred by effect, but physically undetected. Dark Matter bends light, sculpts galaxies, and governs gravitational dynamics, yet it inhabits a metaphysical realm that requires faith to make it real. Unlike the neutrino, it lacks a theoretical platform. The General Theory of Relativity insists it must have mass; the Standard Model offers it no space. It is an effect without a cause: a gravitational fingerprint without a hand.

Yet, physicists are trying to tease it out, not so much to grasp a formless ghost, but rather to catch a glimpse of a wisp, a figment, without knowing how or where to look. To bring light to the dark one must grope around for a switch that may or may not exist.

Researchers at the University of Zurich and the Hebrew University of Jerusalem have devised an experiment called QROCODILE: Quantum Resolution-Optimized Cryogenic Observatory for Dark matter Incident at Low Energy (One can only guess at the amount of time and gin the Docs spent on that acronym 😊) to help tease out the existence of Dark Matter.

The experiment is designed to detect postulated ultralight dark matter particles that may interact with ordinary matter in currently unfathomable ways. To find these particles they have built a detector of superconducting nanowire sensors, cooled to near absolute zero, that achieves an astounding sensitivity to detect an infinitesimally small mass of 0.11 electron-volts (eV).

0.11 eV is roughly the energy difference between two quantum states in a molecule. An imperceptible shiver in the bond between two hydrogen atoms: a mass so slight, it might provoke a murmur of dark matter itself.

Using this detector over a 400-hour run (16.66 days) the team recorded a handful of unexplained signals that are real but not necessarily dark matter. Eventually they hope to achieve detections that resolve directionality, helping distinguish dark matter from background noise. The next phase of the experiment: NILE QROCODILE, (groan*) will move the detectors underground to reduce cosmic interference.

QROCODILE is a shot in the dark. It’s an epistemological paradox: how do you build a detector for something you don’t understand? How, or why, do you build an energy detector for a substance, if it is indeed a substance, that doesn’t emit or absorb energy.

While dark matter is known through its gravitational pull, that detection at a particle level is infeasible. Energy detectors, then, are a complementary strategy, betting on weak or exotic interactions beyond gravity.

Whether it finds Dark Matter or not, QROCODILE reminds us that science begins not with certainty, but with the courage to ask questions in the dark, and the craftsmanship to build instruments that honor the unknown.

* NILE QROCODILE: an acronym that evokes remembrance of the socially awkward Dr. Brackish Okun, a secluded researcher of aliens and their tech at Area 51 in the 1996 movie Independence Day.

Source: …Dark Matter Search with QROCODILE… by Laura Baudis et al, Physical Review Letters, 2025. Graphic: Nile Crocodile Head by Leigh Bedford, 2009. Public Domain.

Cosmos of the Lonely

29 August 2025 By in Physics, Science, Space Tags: , , , , , , , , , , , , , , , , , , , , , , , , , , , , Leave a comment

The universe keeps expanding. When researchers analyze data from the Hubble and James Webb telescopes, alongside a suite of other astronomical tools, they find that the recessional velocity of galaxies, the speed at which they appear to move away from the Earth, varies depending on what they measure.

If they calibrate distances deep into the cosmos using Cepheid variable stars, the expansion rate appears faster than when they use red giant stars or the Cosmic Microwave Background (CMB). This discrepancy, known as the Hubble tension, reveals a deeper mystery: different cosmic yardsticks yield different rates of expansion.

Yet despite the disagreement in values, all methods affirm the same truth: space is stretching…a lot…like a sheet pulled and stretched taut between Atlas’s burden and Hermes flight: a cosmos caught between gravitational pull and a mysterious push: Pushmi-Pullyu on a cosmic scale.

To understand why the cosmos resembles a sheet of rubber we need to travel back about 110 years and peer into the minds of those who first saw increasing separation as a universal law. These new architects of reality: Einstein, Friedmann, Lemaitre; who replaced Newton’s planetary, static models of the cosmos with a dynamic spacetime of bends, ripples, and persistent expansion.

After Einstein published his General Theory of Relativity in 1915, Russian physicist Alexander Friedmann’s analysis of his work showed that the universe could be expanding, and that Einstein’s equations could be used to calculate the rate. In 1927 Belgium priest and physicist Georges Lemaitre proposed that the expansion might be proportional to a galaxy’s velocity relative to its distance from Earth. By 1929, American astronomer Edwin Hubble expanded on Lemaitre’s work and published what became known as Hubble-Lemaitre law: galaxies are moving away from us at speeds proportional to their distance. The greater the distance the faster the speed.

A key feature of this law is the Hubble constant, the proportionality that links velocity and distance. Hubble’s initial estimate for this constant was whopping, and egregiously off, 500 kilometers per second per megaparsec (km/s/Mpc), but as measurements improved, it coalesced around a range between 67 and 73, with the most recent value at 70.4 km/s/Mpc, published by Freedman et al. in May 2025.

The Hubble constant is expressed in kilometers per second per megaparsec. The scale of these units is beyond human comprehension but let’s ground it to something manageable. A megaparsec is about 3.26 million light-years across, and the observable universe, though only 13.8 billion light-years old, has stretched to 46 billion light-years in radius, or 93 billion light-years in diameter, due to the expansion of space (see mind warping explanation below).  

To calculate the recessional velocity across this vast distance, we first convert 46 billion light-years into megaparsecs: which equates to 14,110 megaparsecs. Applying Hubble’s Law: 70 km/s/Mpc times 14,110 Mpc equals 987,700 km/s. This is the rate at which a galaxy 46 billion light-years away would be receding relative to another galaxy one megaparsec closer to Earth.

That’s more than three times the speed of light (299,792 km/sec) or Warp 3 plus in Star Trek parlance. Einstein said this was impossible but fortunately there is some nuance that keeps us in compliance with Special Relativity (or else the fines would be astronomical). This isn’t the speed of a galaxy moving through space, but the speed at which space between galaxies is expanding. Which, admittedly, is terribly confusing.

The speed of a galaxy, composed of matter, energy, and dark matter, must obey Einstein’s rules: gravity and Special Relativity. And one of the rules is that the speed of light is the cosmic speed limit, no one shall pass beyond this.

But space between the galaxies decides to emphasize the rules in a different order. The expansion of space is still governed by Einstein’s equations, just interpreted through the lens of spacetime geometry rather than the motion of objects. This geometry is shaped by, yet not reducible to, matter, energy, and dark matter.

Expansion is a feature of spacetime’s structure, not velocity in the usual sense, and thus isn’t bound by the speed of light. If space wants to expand, stretch, faster than a photon can travel, well so be it.

The space between galaxies is governed by dark energy and its enigmatic rules of geometry. Within galaxies, the rules are set by dark matter, and to a lesser extent by matter and energy, even though dark energy is likely present, its influence at galactic scales is minimal.

Note the use of the word scale here. Galaxies are gigantic, the Milky Way is 100,000-120,000 light-years in diameter. But compared to the universe at 93,000,000,000 light-years across, they’re puny. You would need 845,000 Milky Ways lined up edge-to-edge to span the known universe.

Estimates of the number of galaxies in the universe range from 100 billion to 2 trillion. So, at the scale of the universe, galaxies are mere pinpoints of light; blips of energy scattered across the ever-expanding heavens.

This brings us to dark energy, the mysterious force driving cosmic expansion. No one knows what it is, but perhaps empty space and dark energy are the same. There’s even some speculation, mostly mine, that dark energy is a phase shift of dark matter. A shift in state. A triptych move from Newtonian physics to Quantum Mechanics to…Space Truckin’.

In the beginning moments after the big bang, the universe was dominated by radiation composed of high energy particles and photons. As the universe cooled, the radiation gave way to matter and dark matter. As more time allowed gravity to create structures, black holes emerged and a new force began to dominate, dark energy. But where did the dark energy come from? Was it always part of the universe or did it evolve from other building blocks. Below are a few speculative ideas floating around the cosmic playroom.

J.S. Farnes proposed a unifying theory where dark matter and dark energy are aspects of a single negative mass fluid. This fluid could flatten galaxy rotation curves and drive cosmic expansion, mimicking both phenomena simultaneously.

Mathematicians Tian Ma and Shouhong Wang developed a unified theory that alters Einstein’s field equations to account for a new scalar potential field. Their model suggests that energy and momentum conservation only holds when normal matter, dark matter, and dark energy are considered together.

Ding-Yu Chung proposed a model where dark energy, dark matter, and baryonic matter emerge from a dual universe structure involving positive and negative mass domains. These domains oscillate and transmute across dimensions.

These ideas all rotate around the idea that reality revolves around a concept that everything evolves and that matter and energy, of all forms, flickers in and out of existence depending on dimensional scaffolding of space and the strength of gravity and radiation fields.  Rather than radiation, energy, matter, dark matter, and dark energy as separate entities, these may be expressions of a single evolving field, shaped by phase transitions, scalar dynamics, or symmetry breaking.

Now back to my regularly scheduled program. In August 2025, Quanta Magazine reported on a study led by Nobel laureate Adam Riess using the James Webb Telescope (JWST) to measure over 1,000 Cepheid variable stars with unprecedented precision. Cepheid stars pulsate in brightness over time with a highly predictable rate or rhythm, making them ideal cosmic yardsticks. Riess’s team found a Hubble constant of ~73.4 km/s/Mpc, consistent with previous Hubble Space Telescope measurements of Cepheid stars but still significantly higher than what theory predicts.

That theory comes from the standard model of cosmology: Lambda Cold Dark Matter. According to this framework photons decoupled from the hot electron-proton opaque soup about 380,000 years after the Big Bang went boom, allowing light to travel freely for the first time, and allowing space to be somewhat transparent and visible. This event produced the Cosmic Microwave Background (CMB).

This CMB permeates the universe to this day. It was discovered in 1964 by Bell Lab physicists Arno Penzias and Robert Wilson, who were trying to eliminate background noise from their radio antenna. The noise turned out to be the faint afterglow from the Big Bang, cooled down from its original 3000 Kelvin to a frosty 2.7 Kelvin. They received the Nobel Prize in Physics for this discovery in 1978.

Light from the CMB, as measured by the European Space Agency Planck satellite, has a redshift of approximately 1100, meaning the universe has expanded by a factor of 1100 over the past 13.42 billion years. By analyzing the minute temperature fluctuations in the CMB, Planck can infer the density of matter, dark energy, and curvature of the universe. Inserting these parameters into the Lambda Cold Dark Matter model yields a Hubble constant which turns out to be 67.4 + 1.71 (65.69-69.11). This value is considered the gold standard. Values beyond the Planck measurement are not necessarily wrong, just not understood.

At first glance, the difference between Planck’s 67.4 and Riess’ 73.4 may seem small. But it is cosmically significant. Two galaxies 43 billion light-years away and 3.26 billion light-years apart (1000 Mpc) would have a velocity difference of 6000 km/s or about 189 billion kilometers of increased separation per year. That’s the scale of what small differences in the value can add up to and is referred to as the Hubble tension.

Meanwhile, a competing team of researchers studying red branch and giant branch stars consistently scored the Hubble constant closer to the theoretical prediction of 67.4. This team led by Wendy Freedman believes that Hubble tension, the inability of various methods of measuring the Hubble constant to collapse to a single value, is a result of measurement errors

While some researchers, Wendy Freedman and others, suggest lingering systematic errors may still be at play, the persistence of this discrepancy, across instruments, methods, and team, has led others to speculate about new physics. Among the most provocative ideas: the possibility that the universe’s expansion rate may vary depending on direction, hinting at anisotropic expansion and challenging the long-held assumption of cosmic isotropy. But this seems far-fetched and if true it would likely break the Lambda Cold Dark Matter model into pieces.

And so, the cosmos grows lonelier. Not because the galaxies are fleeing, but because space itself is stretching, a wedge governed by the geometry of expansion. The further they drift apart, the less they interact, a divorce from neglect rather than malice. In time, entire galaxies will slip beyond our cosmic horizon, receding faster than light, unreachable even in principle. A cosmos of the lonely.

Source: The Webb Telescope Further Deepens the Biggest Controversy in Cosmology by Liz Kruesi, Quanta Magazine, 13 August 2024. JWST Observations Reject Unrecognized Crowding of Cepheid Photometry as an Explanation for the Hubble Tension at 8σ Confidence by Riess et al, The Astrophysical Journal Letters, 6 February 2024. Graphic: Cosmic Nebula by Margarita Balashova.

Gravity and Vanilla Black Holes

27 February 2025 By in Physics, Science, Space Tags: , , , , , , , , , , , , , Leave a comment

Einstein’s theory of general relativity, which includes gravity, predicts that black holes have a tricky feature: a singularity. This is a point where space and time are squeezed so tightly that the laws of physics break down—think of it as a cosmic “error message.” To fix this, scientists often turn to exotic matter—hypothetical substances with bizarre properties like negative energy—to smooth things out. However, a team from the University of Barcelona, led by Pablo Bueno, found an alternative. They didn’t need exotic matter at all. Instead, they tweaked Einstein’s gravity by adding an infinite series of extra “rules” (higher-curvature corrections) to the math.

Their solution works in spacetimes with more than four dimensions—beyond our usual height, width, depth, and time. In these higher-dimensional worlds, black holes can exist without singularities. This “smooths out” black holes, making them less mysterious and more like regular objects in spacetime—no weird stuff required.

The presence of extra dimensions doesn’t just fix singularities—it can also change how black holes behave. In higher-dimensional spacetimes, black holes might have different event horizon shapes (the boundary beyond which nothing escapes) or other structural quirks. The Barcelona team’s work shows that these altered properties emerge naturally from gravity in more than four dimensions, offering a fresh perspective on these cosmic giants.

Thinking outside the box, is it possible that these extra dimensions link black holes to “a reality outside regular spacetime,” like wormholes (tunnels through spacetime), braneworlds (parallel universes on higher-dimensional “membranes”), or even gateways to white holes (theoretical opposites of black holes that spit stuff out)? Theories like string theory and braneworld scenarios suggest that extra dimensions might allow such connections. For example, a wormhole could theoretically bridge two distant points in our universe—or even lead to a completely different universe.

While the math of higher dimensions opens the door to these possibilities, it’s all conjecture. The Barcelona team’s work is a major step forward in understanding black holes in higher dimensions, but it doesn’t directly prove connections to other realities.

Source: Grok 3. Regular Black Holes… by Bueno, P. et al., Physics Letter B, February 2025. Graphic: Black Hole Rendering, iStock licensed.

Put Your Lights On

24 January 2025 By in Physics Tags: , , , , , , , , , , , , , , , Leave a comment

A distant galaxy at the edge of the universe and the beginning of time has revealed a remarkable discovery by Yale researchers. They have identified a variable quasar that rapidly brightens as its astrophysical jets periodically align with the position of Earth.

The researchers believe that this quasar, and others like it, played a significant role in bringing light into the early dark universe, alongside massive early stars which preceded the quasars.

Quasars are supermassive black holes at the centers of early galaxies, spinning at relativistic speeds. These early galaxies contained substantial unincorporated material, primordial gas clouds akin to present-day nebulae, which were easily captured by the black hole’s gravity. Near the event horizon of the black hole, this matter is caught in a ‘turbulent’ vortex, creating massive astrophysical jets. These jets, partially composed of ionized plasmas, are expelled at relativistic speeds, extending up to hundreds of light-years from the black hole and perpendicular to its event horizon. As the ionized hydrogen plasmas capture electrons from the neutral hydrogen in the early universe, photons are released, contributing to the illumination of the cosmos.

Thomas Connor, an astronomer at the Chandra X-Ray Center and co-corresponding author of the study, states, “[This] epoch of reionization is considered the end of the universe’s dark ages.”

Trivia: The song Put Your Lights On was written by Erik Schrody (Everlast) and performed with Santana on his 1999 album Supernatural. He wrote the song while recovering from a heart attack, pondering the hope that exists in life.

Source: This Quasar May Have Helped Turn the Lights on… by Shelton, Yale, 2025. Graphic: Black Hole Outflows from Centaurus A, ESO, 2009.

Runaway Black Hole

25 October 2024 By in Science, Space Tags: , , , , , , , Leave a comment

Brandon Specktor with LiveScience reports that ‘in 2023 astronomers reported the detection of something never seen before: a “runaway” black hole…’

The observed black hole with a mass of 20 million suns, is not gravitationally locked to any galaxy. It was spotted streaking darkly through space at more than 3 million miles per hour, or approximately 0.5% the speed of light, dragging a 200,000 light year long string of stars behind it like Christmas lights tied behind Santa’s sleigh.

Possible scenarios that may have sent the black hole on its merry way include various interactions with other massive objects, such as galactic collisions or gravitational recoil of merging black holes.

Source: 5 Space Discoveries that Scientists are Struggling to Explain by Brandon Specktor, LiveScience, 2024.  Graphic: NASA, ESA, Leah Hustak (STScl)

WIMPs

30 August 2024 By in Science Tags: , , , , , Leave a comment

Weakly Interacting Massive Particles or WIMPs are hypothetical dark matter particles that supposedly make up 26-27% of the universe. They are only detectable through their gravitational effects.

In a recent ScienceNews article LUX-ZEPLIN researchers monitoring 10 metric tons of liquid xenon almost a mile below the surface in Lead, South Dakota have reduced the cross-sectional area that WIMPs can interact with normal matter by about 80%.

This reduced area of interaction implies that the particles are even weaker than previously thought. This would make them even harder to detect.  

Triva time: A cube that could hold 10 metric tons of xenon would need to be about 1.5 meters on a side.

Source: The Possibilities for Dark Matter…by Emily Conover, 2024, Science News. Graphic: WIMPs by University of California Berkley, 2013.

Kepler’s Second Law:

17 May 2024 By in Physics Tags: , , , , , Leave a comment

Kepler’s Second Law, first published between 1609 and 1619, describes how a planet’s orbital speed varies along its elliptical orbit around the Sun. As the planet approaches the Sun, the gravitational pull from the Sun is stronger causing the planet to move faster. As a planet moves away from the Sun it slows down.

Kepler’s Second Law in geometric jargon: A line joining a planet and the Sun sweeps out equal areas during equal intervals of time.

Source: Smithsonian, How Things Fly. Graphic of the Planets and the Sun by CactiStaccingCrane 2022.

Giant Before Us

18 December 2022 By in Biography, Books Nonfiction Tags: , , , , , , , , , , , , , , , , , Leave a comment

Isaac Newton

By James Gleick

Published by Pantheon

Copyright: © 2003

Isaac Newton at 46

James Gleick left Harvard in 1976 with a degree in English and a disposition towards independence from the 9 to 5. His initial attempt at independence after college was launching a weekly newspaper in the midwest city of Minneapolis, Minnesota. This endeavor ended in failure within a year, and it would take another 10 years before he could leave his day job, succeeding as an author of history of science and a provider of internet service in New York City.

His first book, Chaos: Making a New Science, was critically acclaimed and a million copy best seller establishing Gleick as a first-rate storyteller of difficult subjects to the lay public. He wrote two other bestsellers, both biographies, Genius: The Life and Science of Richard Feynman in 1992 and Isaac Newton nine years later.

Gleick presents Newton’s life in chronological order, painting a beautiful portrait of his acheivements but also imparting a sense of his being as a human. His accomplishments were beyond exceptional, but his temperament was that of a reluctant member of society at large, not easily befriended, easy to offend, and not quick to forgive. Current hypotheses suggest that Newton may have suffered from Asperger’s Syndrome, one of the milder forms of autism. As a social being he appears a lot like Beethoven, also a genius but also without grace or courtesy.

Issac Newton was born fatherless, on Christmas Day in 1642 according to the Julian calendar, still in use in England at the time, or the less interesting 4 January 1643 by the today’s Gregorian calendar, on a sheep farmstead far north of London in Lincolnshire County. His father died about three months before his birth and in three years he was shuffled off to a grandmother’s care for the next 9 years to keep him away and out of site from his mother’s new husband, Reverend Barnabas Smith. His early education was at the ancient King’s School, already more than two hundred years old when he entered in 1655 and still operates as an all-boys grammer school to this day. Upon finishing at King’s School, he entered Trinity College at Cambridge in 1661 and, except for a year away in 1665, he stayed as a student and professor until 1696. Immediately following Cambridge, he became Warden of the King’s Mint and in 1703 became president of the Royal Society and stayed in that position until he died in 1727.

Newton’s contributions to the world were many and varied. His Three Laws of Motion were revolutionary in the 18th century, and as a testament to their lasting correctness are still taught to every school kid early in their education. The Law of Gravitation explained the orbit of the heavenly bodies and why apples fall and not rise, float, or go sideways. It has since been replaced by Einstein’s General Relativity but is still a particularly good approximation for us lessor mortals. Calculus. Enough said.

Newton also intensely studied the bible, believing that the universe could only exist through the existence of God. He rejected the Trinity believing there is one God, God the Father with Jesus and the Holy Spirit subservient to God. Newton also predicted that the end of times would not come before 2060, 38 short years from now. Still a little early to be maxing out your credit cards.

Newton researched and experimented with alchemy, including looking for the Philosophers Stone and the force that keeps the planets in their orbits. Seeking the Philosophers Stone may have been worthy of Harry Potter but I’m not sure about Newton. Newton never published anything on his alchemy studies, likely because it didn’t make any sense. Now looking for the force that kept planets from falling your head during a walk-in park was worthy of Newton and the rest of the world, especially Einstein. Newton found it and it was called gravity.

My one complaint with Gleick’s book is his derisive commenting on Newton’s fascination with alchemy through today’s lens of knowledge rather than accepting that understanding and meaning in this world changes, sometimes for the better, sometimes not. People respond to the time they live in not to the unknowns of the future. Newton put it this way, “What we know is a drop, what we don’t know is an ocean.” and one can only study the drop that he has.

One of my favorite quotes of Newton or anyone for that matter was, “A man may imagine things that are false, but he can only understand things that are true.” I liked this quote when I first saw it, not because it was profound, it was, but because it was an idea I had promulgated early on in my education, if it didn’t make logical sense, it probably was wrong.

Universal Physics and Local Irrelevance

18 July 2022 By in Books Nonfiction, Uncategorized Tags: , , , , , Leave a comment

Einstein: A Biography

By Jurgen Neffe

Translated by Shelly Frisch

Published by Farrar, Straus and Giroux

Copyright: © 2007

Neffe brings comprehension to relativity but muddles Einstein’s personal life to inaptness.

Neffe’s non-linear telling of Einstein’s life adds little to the story and a lot of unnecessary page flipping for the reader to grasp the author’s intermittent and incomplete style of writing, whereas his layman descriptions of the theory of relativity generally clears the accumulated fog of physics to bring basic understanding Einstein’s science.