Newton's gravity law passes largest-scale test using Atacama telescope
This digest was compiled by AI from multiple sources — links to the originals are below.
Researchers using the Atacama Cosmology Telescope tested gravity across galaxy clusters separated by hundreds of millions of light-years, the largest-scale test of gravity to date. The results, published in Physical Review Letters, show gravitational strength decreases with distance almost exactly as Newton's inverse square law predicts. The finding supports the standard model of cosmology and sharply limits alternatives such as Modified Newtonian Dynamics.
Key Facts
- The test used observations from the Atacama Cosmology Telescope, a three-to-four-story instrument developed largely by Penn researchers led by Mark Devlin.
- The study examined gravity across galaxy clusters separated by hundreds of millions of light-years, making it the largest-scale test of gravity performed so far.
- The results, published in Physical Review Letters, show that gravitational strength decreases with distance almost exactly as Newton's inverse square law predicts.
- The finding sharply limits a class of alternatives, including Modified Newtonian Dynamics (MOND), that attempt to explain unusual cosmic motions by changing the laws of gravity.
The Cosmic Discrepancy
Astronomers have long observed stars and galaxies moving faster than their visible mass appears capable of explaining. University of Pennsylvania researcher Patricio A. Gallardo describes this as a massive discrepancy in the cosmic ledger. The discrepancy points to two possibilities: large amounts of invisible dark matter, or modified fundamental equations for gravity.
The Atacama Test
Gallardo and collaborators used the Atacama Cosmology Telescope, developed largely by Penn researchers led by Mark Devlin, to test gravity on unprecedented scales. The team examined gravity across galaxy clusters separated by hundreds of millions of light-years, the largest-scale test of gravity so far. Results published in Physical Review Letters show gravitational strength decreases with distance almost exactly as Newton's inverse square law predicts.
Implications for Cosmology
Demonstrating that established gravity theories work over enormous distances strengthens the standard model of cosmology. The finding sharply limits alternatives such as Modified Newtonian Dynamics (MOND) that change gravity laws to explain cosmic motions. Newton originally developed the inverse square relation for the Solar System, but scientists have now tested it using masses and distances inconceivable in Newton's day.
1 source
Newton's gravity law passes largest-scale test using Atacama telescope
