For centuries, to know the cosmos meant looking skyward, peering through a lens, and tracking the motions and properties of distant objects and events. Today, finding answers to the universe’s many remaining secrets requires a much broader approach, from research teams that can include thousands of scientists to “lenses” that capture more than light.
Observations of the sky have moved beyond what the eye can see to new telescope designs that capture photons across a broad swath of the electromagnetic spectrum, from radio waves to x–rays to gamma rays, as well as new detectors for messengers like cosmic rays and gravitational waves, elusive remnants from some of the most cataclysmic events in the universe. Instead of simply looking up, astronomers and astrophysicists look all around us, gaining insights from the myriad clues that constantly bombard our planet.
In July, #BroughtToYouByNSF will be highlighting the NSF–funded observations, tech, and people revealing the universe’s secrets, and how they have helped transform the ancient art of stargazing into a new age of multi–messenger exploration.
The universe is streaked with messenger signals, whether radio–wavelength photons from a black hole’s event horizon, neutrinos fired from the jets of a black–hole fueled blazar, or gravitational waves from colliding neutron stars.
Studying the full suite of signals helps scientists build a more comprehensive picture of the universe, as each signal provides a different clue about the nature of the object or event from which it originates.
At NSF, such multi–messenger astrophysics is a high priority — it even drives one of NSF’S Big Ideas — and the decades of investment are paying dividends.
In October 2017, NSF announced that its Laser Interferometer Gravitational–Wave Observatory (LIGO) instrument had detected the collision of neutron stars, an observation that was joined not only by Europe›s Virgo gravitational wave detector, but also by more than 70 telescopes around the globe and in space. In back–to–back press conferences (announcing the gravitational detection and announcing the telescope observations), the discovery marked the first true multi–messenger detection, with gravitational waves joining photons for the first time.
Then, just six months later, NSF announced that its IceCube neutrino detector at the South Pole identified a high–energy neutrino as it passed through polar ice, an observation that allowed telescopes to quickly turn and locate the source: an object astronomers call a blazar.
Even when a single messenger arrives, it can lead to a profound discovery. The April 10 reveal of the first true image of black hole involved an international collaboration and eight telescopes across the globe that crafted the historic image using light from the single wavelength of precisely 1.3 millimeters. It was a profound success for very long baseline interferometry, a technique for uniting distant telescopes to act as a single, enormous dish — a technique NSF helped spearhead from its earliest days.
This month, NSF is highlighting its vast array of ground–based telescopes and detectors, flagship observatories that are leading global efforts to understand the universe as never before. Looking not just skyward, but all around us, NSF discoveries are rewriting textbooks, opening new fields of discovery, and inspiring all of us to think more deeply about our place in the cosmos.