{"id":116231,"date":"2026-09-20T19:08:28","date_gmt":"2026-09-20T23:08:28","guid":{"rendered":"https:\/\/bgodinspired.com\/?p=116231"},"modified":"2026-09-20T19:08:28","modified_gmt":"2026-09-20T23:08:28","slug":"gravitational-constant-physics-cant-pin-down","status":"publish","type":"post","link":"https:\/\/bgodinspired.com\/index.php\/nature-and-creation\/gravitational-constant-physics-cant-pin-down\/","title":{"rendered":"Gravitational Constant: The Number Physics Can&#8217;t Pin Down"},"content":{"rendered":"<div class='booster-block booster-read-block'>\n                <div class=\"twp-read-time\">\n                \t<i class=\"booster-icon twp-clock\"><\/i> <span>Read Time:<\/span>10 Minute, 27 Second                <\/div>\n\n            <\/div><p>Find a magnet no bigger than the head of a pin. Hold it just above a paper clip lying on the floor. The clip jumps up and sticks to it.<\/p>\n\n<p>That tiny magnet just won a tug of war against an entire planet. Earth had its whole mass pulling the clip down. The magnet had almost nothing. The magnet won easily.<\/p>\n\n<p>Gravity is the force you feel every second of your life, and it is by far the weakest force in nature. That weakness is also why the <strong>gravitational constant<\/strong> \u2014 the number that says exactly how strong gravity is \u2014 remains the least precisely known number in physics.<\/p>\n\n<p>Not one of the least precise. The least.<\/p>\n\n<h2>What the gravitational constant is<\/h2>\n\n<p>Physicists call it big G. It is the number you drop into the equation that tells you how hard any two objects pull on each other. Your body and the chair. The Moon and the sea. One galaxy and the galaxy beside it. Same number, every time, everywhere.<\/p>\n\n<p>Every other fundamental constant of nature is known to six or more significant digits. Big G is nowhere near that. Two careful teams can each spend years on it, do everything right, and come out with answers that do not match.<\/p>\n\n<p>The reason is the weakness. To measure electricity, you can push a lot of it through a wire and watch what happens. You cannot turn gravity up. You have to measure a pull so faint that a truck passing outside, a shift in room temperature, or a researcher walking across the floor can bury the signal completely.<\/p>\n\n<p>That does not make gravity measurements useless. Rough ones are still powerful \u2014 decades-old gravity data collected around Mars is what recently revealed that <a href=\"https:\/\/bgodinspired.com\/index.php\/bible-resources\/bible-and-science\/mars-heat-anomaly-still-molten-inside\/\">the planet&#8217;s southern interior is still partly molten<\/a>. It is the last few decimal places that turn into a wall.<\/p>\n\n<div class=\"convertkit-form wp-block-convertkit-form\" style=\"\"><script async data-uid=\"6491fb8269\" src=\"https:\/\/bgodinspired.kit.com\/6491fb8269\/index.js\" data-jetpack-boost=\"ignore\" data-no-defer=\"1\" data-no-optimize=\"1\" nowprocket><\/script><\/div>\n\n\n<h2>Ten years, and a sealed envelope<\/h2>\n\n<p>At the National Institute of Standards and Technology in the United States, a physicist named Stephan Schlamminger spent roughly ten years on a single measurement of big G.<\/p>\n\n<p>The instrument is a descendant of something built in 1798. Henry Cavendish hung weights from a thin fibre and watched the fibre twist as heavier weights were brought close. That is still the basic idea. Schlamminger&#8217;s version used eight metal cylinders \u2014 four sitting on a turntable, four hanging inside on a copper-beryllium ribbon \u2014 shut away from the room.<\/p>\n\n<p>Then he did something unusual. He arranged to be lied to.<\/p>\n\n<p>Not maliciously. He asked a colleague, Patrick Abbott, to quietly subtract a secret number from the mass values he was working with, so that every result he calculated would be off by an amount only Abbott knew. The real number went into a sealed envelope.<\/p>\n\n<p>He did this on purpose, for a specific reason: he was worried that he might unconsciously nudge his own analysis until it agreed with a value a French team had already published. Ten years is a long time to want something. He did not trust himself to stay neutral, so he made it impossible to cheat.<\/p>\n\n<p>The envelope was opened at three in the afternoon on 11 July 2024, in front of a room of colleagues at a conference in Colorado.<\/p>\n\n<h2>The moment it did not line up<\/h2>\n\n<p>His first feeling was relief. The hidden number had roughly the size and direction he had expected, which meant nothing had gone badly wrong.<\/p>\n\n<p>Then the relief drained away. The number was a little too large. Once he applied it, his answer landed at 6.67387 \u00d7 10\u207b\u00b9\u00b9 \u2014 about 0.0235% below the value reported in 2007 by a team at the International Bureau of Weights and Measures in France.<\/p>\n\n<p>Roughly two parts in ten thousand. In almost any other setting, that is a rounding error. Here it is a genuine problem, because the margins of error both teams claim are smaller than the gap between them. They cannot both be right, and nobody can point to what either one did wrong.<\/p>\n\n<p>His team also ran the whole experiment again using sapphire masses instead of copper ones, in case the material itself was hiding something. Virtually the same answer. That closed one door without opening another.<\/p>\n\n<p>The work was published in the journal Metrologia in April 2026. <a href=\"https:\/\/www.nist.gov\/news-events\/news\/2026\/04\/nist-weighs-mystery-gravitational-constant\" target=\"_blank\" rel=\"noopener\">NIST&#8217;s own account of the experiment is here.<\/a><\/p>\n\n<h2>The detail nobody repeats: the error bar is padded by hand<\/h2>\n\n<p>Here is the part that rarely survives into the news write-ups, and it is the most revealing thing in the whole business.<\/p>\n\n<p>An international committee called CODATA publishes the official values of the fundamental constants. Every few years it gathers the best available measurements and issues one recommended number for each.<\/p>\n\n<p>For big G, it had sixteen measurements to work with. Those sixteen do not agree with each other. So the committee does something that reads almost like an admission: it takes the error bars the experimenters themselves reported and multiplies every one of them by 3.9. In the committee&#8217;s own wording, the factor is applied &#8220;to reduce their inconsistencies to an acceptable level.&#8221;<\/p>\n\n<p>Read that again. The published uncertainty on the gravitational constant is not the uncertainty anyone actually achieved. It is nearly four times wider, stretched by hand until the disagreeing results finally overlap.<\/p>\n\n<p>And because no new measurement had arrived in time for the 2022 round, the committee simply carried the 2018 number forward unchanged. The official value for the strength of gravity sat perfectly still for four years \u2014 not because it was settled, but because nothing had happened that could move it.<\/p>\n\n<p>The recommended figure, if you want it, is 6.67430 \u00d7 10\u207b\u00b9\u00b9, give or take about 22 parts per million. Set that beside constants known to six or more digits and you can see why physicists find this one uncomfortable.<\/p>\n\n<p>If that unsettles you, it may help to know that unfinished business at the foundations is normal rather than scandalous. <a href=\"https:\/\/bgodinspired.com\/index.php\/bible-resources\/bible-and-science\/largest-survey-of-physicists\/\">The largest survey of physicists ever run<\/a> asked 1,675 of them about the biggest questions in their field, and only two of those questions drew a majority answer. And the limits of measurement itself come up more often than the textbooks advertise \u2014 there is a similar puzzle hiding inside the question of <a href=\"https:\/\/bgodinspired.com\/index.php\/bible-resources\/bible-and-science\/can-a-clock-be-perfectly-accurate\/\">whether a clock can ever be perfectly accurate<\/a>.<\/p>\n\n<h2>The part that is not really about physics<\/h2>\n\n<p>Strip the equipment away and what is left is a story about a man who did not trust his own wanting.<\/p>\n\n<p>He had spent ten years on it. He had, in his own words, dotted all the i&#8217;s and crossed all the t&#8217;s. He was as confident as a careful person ever gets. And he still handed the answer to somebody else and asked to be kept in the dark \u2014 because being confident is exactly the state in which people begin to see what they were hoping to see.<\/p>\n\n<p>That is not a physics skill. It is a character skill, and it is rarer than the equipment.<\/p>\n\n<p>There is something else sitting quietly underneath the whole story, too. Of everything we have learned to count, the thing we count worst is the thing doing the holding. The force that keeps your feet on the ground, the sea in its bed and the planets in their lanes is the one we can barely pin down. Long before anyone hung weights from a fibre, there were writers who said the world does not hold itself up \u2014 that all things hold together because God holds them. They were not measuring anything. But they were pointing at the same shape of idea: whatever is doing the holding is not the part you get your hands around easily.<\/p>\n\n<h2>Where it stands now<\/h2>\n\n<p>The gap is still open. Schlamminger has said he has given this enough of his life, and that he will leave the problem to younger generations of scientists.<\/p>\n\n<p>He also said something worth carrying out of the laboratory. &#8220;Every measurement is important, because the truth matters,&#8221; he said. For him, making an accurate measurement is a way of bringing order to the universe \u2014 whether or not the number agrees with the expected value.<\/p>\n\n<p><em>Whether or not the number agrees with the expected value.<\/em> That is the whole discipline in one line.<\/p>\n\n<p>Most of us will never measure a constant. But nearly everyone is carrying around a number they badly want to come out a certain way \u2014 what something cost, how long it really took, how much is left, whose fault it was. We almost never think to hide the answer from ourselves before we go looking for it.<\/p>\n\n<p>The people who got closest to gravity got there by refusing to peek. That part does not need a laboratory.<\/p>\n\n<h2>Questions People Ask About the Gravitational Constant<\/h2>\n\n<h3>What is the gravitational constant?<\/h3>\n\n<p>The gravitational constant, written as big G, is the number in Newton&#8217;s law of gravitation that sets how strongly any two masses pull on each other. Its currently recommended value is about 6.6743 \u00d7 10\u207b\u00b9\u00b9 cubic metres per kilogram per second squared. It is the same everywhere and applies to everything \u2014 a person and a chair, the Moon and the sea, one galaxy and the next.<\/p>\n\n<h3>Why is the gravitational constant so hard to measure?<\/h3>\n\n<p>Gravity is by far the weakest of nature&#8217;s forces. A magnet the size of a pinhead can lift a paper clip against the pull of the entire Earth. Because the force is so faint, an experiment measuring it is easily disturbed by vibrations, temperature shifts, air movement and nearby masses. Gravity also cannot be turned up the way an electric current can, so every measurement is a fight against noise rather than a straightforward reading.<\/p>\n\n<h3>What value did NIST measure for the gravitational constant?<\/h3>\n\n<p>A team at the US National Institute of Standards and Technology, led by Stephan Schlamminger, measured G as 6.67387 \u00d7 10\u207b\u00b9\u00b9 cubic metres per kilogram per second squared, published in the journal Metrologia in April 2026. The result is 0.0235% lower than the value measured in 2007 by a team at the International Bureau of Weights and Measures in France, and the two do not agree within the margins of error each team stated.<\/p>\n\n<h3>Why do scientists blind their own experiments?<\/h3>\n\n<p>Blinding hides the true result from the researchers while they analyse their data, so they cannot unconsciously steer the analysis toward the answer they expect or hope for. In the NIST gravity experiment, a colleague subtracted a secret number from the mass values and sealed that number in an envelope, which was opened only once the analysis was finished. Blinding does not make an experiment more sensitive; it protects the experiment from the people running it.<\/p>\n\n<h3>Is the gravitational constant actually changing?<\/h3>\n\n<p>There is no accepted evidence that the gravitational constant varies. Most physicists attribute the disagreement between experiments to unidentified systematic errors in the measurements rather than to a constant that shifts over time. The honest position is that the discrepancy is unresolved: nobody has identified what is wrong with any particular experiment, and nobody has shown that big G is anything other than fixed.<\/p>\n\n<h2>Something to Talk About<\/h2>\n\n<p>Schlamminger deliberately made it impossible to see his own result until the work was finished. Is that kind of self-imposed blindness the mark of someone more trustworthy than most \u2014 or a sign that we have quietly stopped expecting people to be honest without a safeguard? Tell us where you land in the comments. We read them.<\/p>\n\n<div class=\"convertkit-form wp-block-convertkit-form\" style=\"\"><script async data-uid=\"6491fb8269\" src=\"https:\/\/bgodinspired.kit.com\/6491fb8269\/index.js\" data-jetpack-boost=\"ignore\" data-no-defer=\"1\" data-no-optimize=\"1\" nowprocket><\/script><\/div>\n\n\n<h2>Share This<\/h2>\n\n<p>A magnet the size of a pinhead beats the whole planet in a tug of war. That is how weak gravity is \u2014 and it is why the number behind it is still the worst-measured value in all of physics. https:\/\/bgodinspired.com\/index.php\/nature-and-creation\/gravitational-constant-physics-cant-pin-down\/<\/p>\n\n<p>A physicist spent ten years measuring gravity, then had a colleague hide the answer from him in a sealed envelope \u2014 because he knew that after ten years, he would want a particular result. Honestly one of the best things I have read all month. https:\/\/bgodinspired.com\/index.php\/nature-and-creation\/gravitational-constant-physics-cant-pin-down\/<\/p>\n\n<p>Did not know this: the official uncertainty on the gravitational constant is padded by a factor of 3.9, by hand, because the sixteen best measurements refuse to agree with each other. 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hand.<\/p>\n","protected":false},"author":1,"featured_media":116230,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_monsterinsights_skip_tracking":false,"_wp_convertkit_post_meta":{"form":"-1","landing_page":"0","tag":"0","restrict_content":"0"},"footnotes":""},"categories":[5226,3708],"tags":[],"class_list":["post-116231","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-bgodinspired-science-news","category-nature-and-creation"],"_links":{"self":[{"href":"https:\/\/bgodinspired.com\/index.php\/wp-json\/wp\/v2\/posts\/116231","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/bgodinspired.com\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/bgodinspired.com\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/bgodinspired.com\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/bgodinspired.com\/index.php\/wp-json\/wp\/v2\/comments?post=116231"}],"version-history":[{"count":1,"href":"https:\/\/bgodinspired.com\/index.php\/wp-json\/wp\/v2\/posts\/116231\/revisions"}],"predecessor-version":[{"id":116233,"href":"https:\/\/bgodinspired.com\/index.php\/wp-json\/wp\/v2\/posts\/116231\/revisions\/116233"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/bgodinspired.com\/index.php\/wp-json\/wp\/v2\/media\/116230"}],"wp:attachment":[{"href":"https:\/\/bgodinspired.com\/index.php\/wp-json\/wp\/v2\/media?parent=116231"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/bgodinspired.com\/index.php\/wp-json\/wp\/v2\/categories?post=116231"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/bgodinspired.com\/index.php\/wp-json\/wp\/v2\/tags?post=116231"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}