It may not feel like it, but everything in the universe is in constant motion. Our Sun, with all its planets, orbits the center of the Milky Way, flying through the cosmos at around 450,000 miles per hour (720,000 kilometers per hour), completing one full orbit in about 230 million years, according to NASA.
Astronomers measure the speed at which the solar system is hurtling through space by mapping surrounding galaxies and observing how light from other objects is shifted. New measurements, however, put the existing models to the test and found that the solar system may in fact be much speedier than previously believed.
A team of researchers used extremely sensitive instruments to detect a subtle headwind created by the motion of the solar system and found that our host star and neighboring planets are moving more than three times faster than current models predict. The study, published in Physical Review Letters, challenges the standard model of cosmology and our understanding of how the universe evolved since the Big Bang.
Speeding through
The scientists behind the recent study turned to radio galaxies to hone in on the speed at which the solar system travels. Radio galaxies are an excellent source of radio waves, emitting as much as one trillion solar luminosities of radiation with long wavelengths.
The team analyzed the distribution of radio galaxies using the LOFAR (Low Frequency Array) telescope, a radio telescope network that stretches across Europe, combined with data from two additional radio observatories. As the solar system moves through the cosmos, it creates a subtle headwind whereby more radio galaxies appear in the direction in which it’s traveling.
The researchers also applied a new statistical method that accounts for the fact that many radio galaxies consist of multiple components, producing a more accurate analysis of the solar system’s speed.
Combining the data revealed that the distribution of radio galaxies is 3.7 times stronger than what the standard model currently predicts.
“If our solar system is indeed moving this fast, we need to question fundamental assumptions about the large-scale structure of the universe,” Dominik Schwarz, cosmologist at Bielefeld University and co-author of the study, said in a statement. “Alternatively, the distribution of radio galaxies itself may be less uniform than we have believed. In either case, our current models are being put to the test.”
Either way, we’re zipping around the galaxy at a rapid clip, even if a firm grasp on why, or what it means for the universe, remains out of reach.