Elon Musk thinks future economies could measure wealth using the laws of physics instead of dollars. The Tesla and SpaceX CEO predicts that advances in robotics and space exploration could eventually make conventional money irrelevant.Musk outlined this vision during a conversation with biographer Walter Isaacson on The Builders podcast. He suggested that a multiplanetary civilization could adopt a radically different way to measure economic value, based on physical resources and energy.Currency measured in physicsMusk expects future currencies to reflect fundamental physical quantities, including power, mass, and energy. He specifically cited wattage and tonnage as possible measures of value.“I think currency will be measured in fundamental physics metrics,” Musk told Isaacson, describing a system built around those physical quantities.Such a shift would challenge the foundations of modern finance. Today, the US dollar provides a common measure for pricing goods, paying workers, and trading assets. Musk’s vision suggests that technological abundance could eventually reduce the importance of conventional currencies.However, measuring economic value through physical quantities would require a system for comparing different resources. A watt measures power, while mass measures the quantity of matter. Neither independently captures scarcity, usefulness, or demand.Musk connected his prediction to a future shaped by robotics and space travel. A multiplanetary economy could face resource constraints that differ significantly from those on Earth.Robots could solve US debtMusk also argued that robotics and artificial intelligence could provide the only viable solution to America’s growing national debt. He reached that conclusion after his 130-day stint as a special government employee in the Trump administration in 2025.“I came to the conclusion that the only way we’re going to solve the national debt is with AI and robots,” Musk told Isaacson. He dismissed spending cuts as an unrealistic way to close the gap.The US national debt reached a record $40 trillion in August 2026, according to the supplied report. Musk argued that political resistance would prevent Washington from making sufficiently deep spending reductions.His alternative depends on machines dramatically increasing productivity. Automated production could generate more goods and services with less human labor. Yet higher productivity alone would not guarantee lower federal debt. The government would still need to capture enough economic gains through taxes or other revenue.Musk’s wealth faces a countdownMusk also expects his personal fortune to shrink substantially across future generations. He said taxes would gradually erode his wealth, leaving his descendants with a small fraction of his current holdings.Bloomberg’s Billionaire Index valued Musk’s net worth at approximately $921 billion at Monday’s close. His fortune primarily reflects his ownership stakes in Tesla and SpaceX, which he says help him retain control over both companies.SpaceX’s financial performance has also strengthened its position. The company reported its first quarterly profit as a public company on Tuesday, posting $4.4 billion in net income for the third quarter of 2026. Revenue jumped 161% year over year to $14.6 billion, compared with $5.6 billion in the same quarter last year. SpaceX had recorded a $1.1 billion net loss in the year-ago quarter.Q3 2026 highlights:– Delivered revenue of $14.6 billion, up 161% year-over-year– Successfully launched our first revenue-generating Starship mission, delivering 26 Starlink V3 satellites to our broadband constellation, representing approximately 10x the downlink capacity added… pic.twitter.com/Qr94io6PiW— SpaceX (@SpaceX) October 20, 2026He wants his foundation to continue funding his long-term ambitions after his death. Those priorities include making humanity multiplanetary, expanding consciousness beyond Earth, and improving sustainable energy.Musk also pledged to give every American child a SpaceX share next year. The proposed contribution carries a reported value exceeding $10 billion at current prices.His predictions ultimately rest on a sweeping assumption: technological progress could transform the relationship between resources, productivity and wealth. Whether machines can make conventional money obsolete remains an open question.