{"id":51360,"date":"2026-03-05T15:11:23","date_gmt":"2026-03-05T15:11:23","guid":{"rendered":"https:\/\/idea.membrane.com\/songwriter\/?p=51360"},"modified":"2026-03-05T15:11:23","modified_gmt":"2026-03-05T15:11:23","slug":"retro-future","status":"publish","type":"post","link":"https:\/\/kingarthur.com\/songwriter\/2026\/03\/05\/retro-future\/","title":{"rendered":"Retro-Future"},"content":{"rendered":"<p>[Silence]<\/p>\n<p>[Instrumental, Guitar, Piano, Organ, Synth, Bass, Percussion, Drums]<\/p>\n<p>[Intro]<br \/>\n[Instrumental Intro: Pulsing Bass, Organ Swell, Muted Guitar Chops, Rising Synth Filter]<br \/>\n[Minimal Beat, Sub Bass, Spoken Vocal]<br \/>\nAt last&#8230;<br \/>\nWelcome (back)<br \/>\nFrom the past<br \/>\nBeen waiting for you&#8230;<br \/>\nWelcome (to)<br \/>\nThe future<br \/>\n(For sure)<br \/>\n[Instrumental]<br \/>\n[Guitar Solo]<br \/>\n[Organ Stabs, Driving Bass, Snare March]<\/p>\n<p>[Bridge \u2013 Breakdown]<br \/>\n[Percussion, Sub Bass, Spoken Vocal]<br \/>\nDid you hear&#8230;<br \/>\n(We&#8217;re here!)<\/p>\n<p>[Refrain]<br \/>\nAt last&#8230;<br \/>\nWelcome (back)<br \/>\nFrom the past<br \/>\nBeen waiting for you&#8230;<br \/>\nWelcome (to)<br \/>\nThe future<br \/>\n(For sure)<br \/>\nNow&#8230; (endure!)<br \/>\n[Instrumental]<br \/>\n[Guitar Solo]<br \/>\n[Organ Stabs, Driving Bass, Snare March]<\/p>\n<p>[Bridge \u2013 Breakdown]<br \/>\n[Percussion, Sub Bass, Spoken Vocal]<br \/>\nDid you hear?<br \/>\nTo be perfectly clear!<br \/>\n(We&#8217;re here!)<\/p>\n<p>[Refrain]<br \/>\nCame on fast<br \/>\nNo more (slack)<br \/>\nWelcome (back)<br \/>\nFrom the past<br \/>\nBeen waiting for you&#8230;<br \/>\nWelcome (to)<br \/>\nThe future<br \/>\n(For sure)<br \/>\nNow&#8230; (endure!)<br \/>\n[Instrumental]<br \/>\n[Guitar Solo]<br \/>\n[Organ Stabs, Driving Bass, Snare March]<\/p>\n<p>[Bridge \u2013 Breakdown]<br \/>\n[Percussion, Sub Bass, Spoken Vocal]<br \/>\nDid you hear?<br \/>\nTo be perfectly clear!<br \/>\n(We&#8217;re here!)<br \/>\nThe present is very, very&#8230;<br \/>\n(Near!)<\/p>\n<p>[Outro]<br \/>\nCame on fast<br \/>\nNo more (slack)<br \/>\nWelcome (back)<br \/>\nFrom the past<br \/>\nBeen waiting for you&#8230;<br \/>\nWelcome (to)<br \/>\nThe future<br \/>\n(For sure)<br \/>\nEndure<br \/>\n(Some more!)<\/p>\n<p>ABOUT THE SONG<\/p>\n<p data-start=\"0\" data-end=\"191\">The connection between <strong data-start=\"23\" data-end=\"54\">energy (measured in joules)<\/strong> and the <strong data-start=\"63\" data-end=\"87\">space-time continuum<\/strong> comes mainly from <strong data-start=\"106\" data-end=\"120\">relativity<\/strong>, where energy and matter directly influence the geometry of spacetime.<\/p>\n<h3 data-start=\"193\" data-end=\"223\">1. Energy curves spacetime<\/h3>\n<p data-start=\"224\" data-end=\"334\">In <span class=\"hover:entity-accent entity-underline inline cursor-pointer align-baseline\"><span class=\"whitespace-normal\">General Relativity<\/span><\/span>, developed by <span class=\"hover:entity-accent entity-underline inline cursor-pointer align-baseline\"><span class=\"whitespace-normal\">Albert Einstein<\/span><\/span>, the key idea is:<\/p>\n<blockquote data-start=\"336\" data-end=\"433\">\n<p data-start=\"338\" data-end=\"433\"><strong data-start=\"338\" data-end=\"433\">Energy and mass tell spacetime how to curve, and curved spacetime tells matter how to move.<\/strong><\/p>\n<\/blockquote>\n<p data-start=\"435\" data-end=\"527\">Energy is measured in <strong data-start=\"457\" data-end=\"467\">joules<\/strong>, and all forms of energy contribute to spacetime curvature:<\/p>\n<ul data-start=\"528\" data-end=\"623\">\n<li data-start=\"528\" data-end=\"543\">\n<p data-start=\"530\" data-end=\"543\">Mass energy<\/p>\n<\/li>\n<li data-start=\"544\" data-end=\"562\">\n<p data-start=\"546\" data-end=\"562\">Kinetic energy<\/p>\n<\/li>\n<li data-start=\"563\" data-end=\"591\">\n<p data-start=\"565\" data-end=\"591\">Radiation energy (light)<\/p>\n<\/li>\n<li data-start=\"592\" data-end=\"623\">\n<p data-start=\"594\" data-end=\"623\">Pressure and stress in matter<\/p>\n<\/li>\n<\/ul>\n<p data-start=\"625\" data-end=\"667\">These appear in Einstein\u2019s field equation:<\/p>\n<p><span class=\"katex-display\"><span class=\"katex\"><span class=\"katex-mathml\">G\u03bc\u03bd=8\u03c0Gc4T\u03bc\u03bdG_{\\mu\\nu} = \\frac{8\\pi G}{c^4} T_{\\mu\\nu}<\/span><span class=\"katex-html\" aria-hidden=\"true\"><span class=\"base\"><span class=\"mord\"><span class=\"mord mathnormal\">G<\/span><span class=\"msupsub\"><span class=\"vlist-t vlist-t2\"><span class=\"vlist-r\"><span class=\"vlist\"><span class=\"sizing reset-size6 size3 mtight\"><span class=\"mord mtight\"><span class=\"mord mathnormal mtight\">\u03bc\u03bd<\/span><\/span><\/span><\/span><span class=\"vlist-s\">\u200b<\/span><\/span><\/span><\/span><\/span><span class=\"mrel\">=<\/span><\/span><span class=\"base\"><span class=\"mord\"><span class=\"mfrac\"><span class=\"vlist-t vlist-t2\"><span class=\"vlist-r\"><span class=\"vlist\"><span class=\"mord mathnormal\">c<\/span><span class=\"msupsub\"><span class=\"vlist-t\"><span class=\"sizing reset-size6 size3 mtight\"><span class=\"mord mtight\">4<\/span><\/span><\/span><\/span>8<span class=\"mord mathnormal\">\u03c0<\/span><span class=\"mord mathnormal\">G<\/span><\/span><span class=\"vlist-s\">\u200b<\/span><\/span><\/span><\/span><\/span><span class=\"mord\"><span class=\"mord mathnormal\">T<\/span><span class=\"msupsub\"><span class=\"vlist-t vlist-t2\"><span class=\"vlist-r\"><span class=\"vlist\"><span class=\"sizing reset-size6 size3 mtight\"><span class=\"mord mtight\"><span class=\"mord mathnormal mtight\">\u03bc\u03bd<\/span><\/span><\/span><\/span><span class=\"vlist-s\">\u200b<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/p>\n<p data-start=\"719\" data-end=\"909\">The term <strong data-start=\"728\" data-end=\"746\"><span class=\"katex\"><span class=\"katex-mathml\">T\u03bc\u03bdT_{\\mu\\nu}<\/span><span class=\"katex-html\" aria-hidden=\"true\"><span class=\"base\"><span class=\"mord\"><span class=\"mord mathnormal\">T<\/span><span class=\"msupsub\"><span class=\"vlist-t vlist-t2\"><span class=\"vlist-r\"><span class=\"vlist\"><span class=\"sizing reset-size6 size3 mtight\"><span class=\"mord mtight\"><span class=\"mord mathnormal mtight\">\u03bc\u03bd<\/span><\/span><\/span><\/span><span class=\"vlist-s\">\u200b<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/strong> (the <strong data-start=\"752\" data-end=\"776\">stress-energy tensor<\/strong>) represents <strong data-start=\"789\" data-end=\"825\">energy density and momentum flow<\/strong> \u2014 essentially how many <strong data-start=\"849\" data-end=\"870\">joules per volume<\/strong> are present and how that energy moves.<\/p>\n<p data-start=\"911\" data-end=\"914\">So:<\/p>\n<p data-start=\"916\" data-end=\"975\"><strong data-start=\"916\" data-end=\"975\">More energy (joules) \u2192 stronger curvature of spacetime.<\/strong><\/p>\n<h3 data-start=\"982\" data-end=\"1013\">2. Mass is energy (E = mc\u00b2)<\/h3>\n<p data-start=\"1014\" data-end=\"1084\">Another famous relation from <span class=\"hover:entity-accent entity-underline inline cursor-pointer align-baseline\"><span class=\"whitespace-normal\">Special Relativity<\/span><\/span> is:<\/p>\n<p><span class=\"katex-display\"><span class=\"katex\"><span class=\"katex-mathml\">E=mc2E = mc^2<\/span><span class=\"katex-html\" aria-hidden=\"true\"><span class=\"base\"><span class=\"mord mathnormal\">E<\/span><span class=\"mrel\">=<\/span><\/span><span class=\"base\"><span class=\"mord mathnormal\">m<\/span><span class=\"mord\"><span class=\"mord mathnormal\">c<\/span><span class=\"msupsub\"><span class=\"vlist-t\"><span class=\"vlist-r\"><span class=\"vlist\"><span class=\"sizing reset-size6 size3 mtight\"><span class=\"mord mtight\">2<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/p>\n<p data-start=\"1102\" data-end=\"1156\">This means mass is simply <strong data-start=\"1128\" data-end=\"1155\">energy stored in matter<\/strong>.<\/p>\n<p data-start=\"1158\" data-end=\"1166\">Example:<\/p>\n<ul data-start=\"1167\" data-end=\"1235\">\n<li data-start=\"1167\" data-end=\"1235\">\n<p data-start=\"1169\" data-end=\"1235\"><strong data-start=\"1169\" data-end=\"1185\">1 kg of mass<\/strong> contains about<br data-start=\"1200\" data-end=\"1203\" \/><strong data-start=\"1205\" data-end=\"1224\">9 \u00d7 10\u00b9\u2076 joules<\/strong> of energy.<\/p>\n<\/li>\n<\/ul>\n<p data-start=\"1237\" data-end=\"1313\">Because that energy exists, the mass <strong data-start=\"1274\" data-end=\"1293\">warps spacetime<\/strong>, producing gravity.<\/p>\n<h3 data-start=\"1320\" data-end=\"1361\">3. Energy density shapes the universe<\/h3>\n<p data-start=\"1362\" data-end=\"1479\">In <span class=\"hover:entity-accent entity-underline inline cursor-pointer align-baseline\"><span class=\"whitespace-normal\">Cosmology<\/span><\/span>, the <strong data-start=\"1408\" data-end=\"1442\">energy density of the universe<\/strong> (joules per cubic meter) determines:<\/p>\n<ul data-start=\"1481\" data-end=\"1549\">\n<li data-start=\"1481\" data-end=\"1497\">\n<p data-start=\"1483\" data-end=\"1497\">expansion rate<\/p>\n<\/li>\n<li data-start=\"1498\" data-end=\"1525\">\n<p data-start=\"1500\" data-end=\"1525\">curvature of the universe<\/p>\n<\/li>\n<li data-start=\"1526\" data-end=\"1549\">\n<p data-start=\"1528\" data-end=\"1549\">evolution of galaxies<\/p>\n<\/li>\n<\/ul>\n<p data-start=\"1551\" data-end=\"1614\">This is described by the <span class=\"hover:entity-accent entity-underline inline cursor-pointer align-baseline\"><span class=\"whitespace-normal\">Friedmann Equations<\/span><\/span>.<\/p>\n<p data-start=\"1616\" data-end=\"1637\">Typical values today:<\/p>\n<ul data-start=\"1638\" data-end=\"1692\">\n<li data-start=\"1638\" data-end=\"1692\">\n<p data-start=\"1640\" data-end=\"1692\">total cosmic energy density \u2248 <strong data-start=\"1670\" data-end=\"1692\">10\u207b\u2079 joules per m\u00b3<\/strong><\/p>\n<\/li>\n<\/ul>\n<p data-start=\"1694\" data-end=\"1770\">Even this tiny amount determines the <strong data-start=\"1731\" data-end=\"1769\">large-scale structure of spacetime<\/strong>.<\/p>\n<h3 data-start=\"1777\" data-end=\"1812\">4. Extreme example: black holes<\/h3>\n<p data-start=\"1813\" data-end=\"1870\">A huge concentration of energy creates extreme curvature.<\/p>\n<p data-start=\"1872\" data-end=\"2004\">A <span class=\"hover:entity-accent entity-underline inline cursor-pointer align-baseline\"><span class=\"whitespace-normal\">Black Hole<\/span><\/span> forms when energy\/mass is compressed enough that spacetime curves into an <strong data-start=\"1986\" data-end=\"2003\">event horizon<\/strong>.<\/p>\n<p data-start=\"2006\" data-end=\"2018\">For example:<\/p>\n<ul data-start=\"2019\" data-end=\"2075\">\n<li data-start=\"2019\" data-end=\"2049\">\n<p data-start=\"2021\" data-end=\"2049\">The mass-energy of the Sun<\/p>\n<\/li>\n<li data-start=\"2050\" data-end=\"2075\">\n<p data-start=\"2052\" data-end=\"2075\">\u2248 <strong data-start=\"2054\" data-end=\"2075\">1.8 \u00d7 10\u2074\u2077 joules<\/strong><\/p>\n<\/li>\n<\/ul>\n<p data-start=\"2077\" data-end=\"2144\">Compressed into a small region \u2192 spacetime folds into a black hole.<\/p>\n<hr data-start=\"2146\" data-end=\"2149\" \/>\n<p data-start=\"2151\" data-end=\"2185\"><strong data-start=\"2153\" data-end=\"2185\">Simple way to think about it<\/strong><\/p>\n<ul data-start=\"2187\" data-end=\"2351\">\n<li data-start=\"2187\" data-end=\"2217\">\n<p data-start=\"2189\" data-end=\"2217\"><strong data-start=\"2189\" data-end=\"2215\">Joules measure energy.<\/strong><\/p>\n<\/li>\n<li data-start=\"2218\" data-end=\"2271\">\n<p data-start=\"2220\" data-end=\"2271\"><strong data-start=\"2220\" data-end=\"2269\">Energy determines the curvature of spacetime.<\/strong><\/p>\n<\/li>\n<li data-start=\"2272\" data-end=\"2351\">\n<p data-start=\"2274\" data-end=\"2351\">Therefore <strong data-start=\"2284\" data-end=\"2351\">joules indirectly measure how strongly spacetime can be warped.<\/strong><\/p>\n<\/li>\n<\/ul>\n<hr data-start=\"2353\" data-end=\"2356\" \/>\n<p data-start=\"2358\" data-end=\"2388\">\u00a0<strong data-start=\"2361\" data-end=\"2388\">A useful mental picture<\/strong><\/p>\n<p data-start=\"2390\" data-end=\"2430\">Imagine spacetime as a stretched fabric:<\/p>\n<ul data-start=\"2432\" data-end=\"2564\">\n<li data-start=\"2432\" data-end=\"2499\">\n<p data-start=\"2434\" data-end=\"2499\">A <strong data-start=\"2436\" data-end=\"2476\">large amount of energy (many joules)<\/strong> makes a <strong data-start=\"2485\" data-end=\"2498\">deep dent<\/strong>.<\/p>\n<\/li>\n<li data-start=\"2500\" data-end=\"2564\">\n<p data-start=\"2502\" data-end=\"2564\">A <strong data-start=\"2504\" data-end=\"2530\">small amount of energy<\/strong> makes only a <strong data-start=\"2544\" data-end=\"2563\">tiny distortion<\/strong>.<\/p>\n<\/li>\n<\/ul>\n<p data-start=\"2566\" data-end=\"2625\">Gravity is simply objects moving through those distortions.<\/p>\n<p><strong>From the album &#8220;<a href=\"\/albums\/Joules\/\">Joules<\/a>&#8220;<\/strong><\/p>\n","protected":false},"excerpt":{"rendered":"<p>[Silence] [Instrumental, Guitar, Piano, Organ, Synth, Bass, Percussion, Drums] [Intro] [Instrumental Intro: Pulsing Bass, Organ Swell, Muted Guitar Chops, Rising Synth Filter] [Minimal Beat, Sub Bass, Spoken Vocal] At last&#8230; Welcome (back) From the past Been waiting for you&#8230; Welcome (to) The future (For sure) [Instrumental] [Guitar Solo] [Organ Stabs, Driving Bass, Snare March] [Bridge [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"nf_dc_page":"","footnotes":""},"categories":[3],"tags":[],"class_list":["post-51360","post","type-post","status-publish","format-standard","hentry","category-4d-music"],"_links":{"self":[{"href":"https:\/\/kingarthur.com\/songwriter\/wp-json\/wp\/v2\/posts\/51360","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/kingarthur.com\/songwriter\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/kingarthur.com\/songwriter\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/kingarthur.com\/songwriter\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/kingarthur.com\/songwriter\/wp-json\/wp\/v2\/comments?post=51360"}],"version-history":[{"count":5,"href":"https:\/\/kingarthur.com\/songwriter\/wp-json\/wp\/v2\/posts\/51360\/revisions"}],"predecessor-version":[{"id":51390,"href":"https:\/\/kingarthur.com\/songwriter\/wp-json\/wp\/v2\/posts\/51360\/revisions\/51390"}],"wp:attachment":[{"href":"https:\/\/kingarthur.com\/songwriter\/wp-json\/wp\/v2\/media?parent=51360"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/kingarthur.com\/songwriter\/wp-json\/wp\/v2\/categories?post=51360"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/kingarthur.com\/songwriter\/wp-json\/wp\/v2\/tags?post=51360"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}