On supporting science journalism
If you're enjoying this article, consider supporting our award-winning journalism by subscribing. By purchasing a subscription you are helping to ensure the future of impactful stories about the discoveries and ideas shaping our world today.
The collision of two galaxy clusters provides the best evidence yet of dark matter, the invisible substance theorized to dominate the mass of the universe. Images taken by the Chandra X-ray Observatory show that the larger cluster dragged out the bulk of the observable mass from the smaller one, in the form of hot plasma. According to theory, the collision should have separated the plasma from dark matter. Scientists determined how parts of the collided clusters bent light behind them via gravitational lensing—the more refraction, the greater the gravity in that area. They found that the plasma did not produce the strongest lensing, indicating that some other unseen mass was doing most of the bending. The latest results, described in the September 10 Astrophysical Journal Letters, do not indicate what the dark matter is, but they do undermine approaches that radically rework conventional gravitational theory.
Subscribe to Support Independent Journalism
Great science journalism requires human expertise, time, effort and creativity. And it costs money. That’s why I and the journalists here at Scientific American hope you’ll join our community.
When you subscribe, you are supporting staff and freelance journalists who are passionate about telling science stories that are true, important and compelling. Our editors and reporters are often experts in their fields, which means they understand the nuances of big discoveries and can untangle the breakthroughs from the hype. With a subscription, you are also supporting rigorous fact-checking to ensure the words we publish are precise and accurate. And you’re supporting original illustrations, graphics and photos that bring you closer to an advanced laboratory, an ice sheet in Antarctica or a space mission in orbit. You’re helping us craft other types of high-quality journalism as well: Our newsletters are carefully written, edited and curated by staffers you have or will come to know and love. Our Science Quickly podcast is based on original reporting, collaboration with editors and scientists and exacting production.
Subscriptions keep this engine running so we can continue to deliver thoughtful, rigorous and independent science journalism to you. In an era of viral misinformation, this work is crucial. If you value what we do, I hope you’ll consider joining us as a subscriber
