Exploring the Cosmic Frontier

In my last post, I talked about the international Large Synoptic Survey Telescope project and the genesis of Brookhaven’s participation in it. We’re now playing a major role in developing the digital “film” that will capture the most detailed images ever of the southern sky when LSST comes online in the early 2020s. We are all really excited for that day, but as scientists typically do, we’ve already started asking, “what's next after LSST?”

Several other observational techniques can fill in the details that LSST will not be able to see. One approach is to look at the sky in radio wavelengths. Pictures produced by a radiotelescope, for example, are in 3D, rather than the 2D versions an optical telescope creates. The third dimension comes from the redshift, which is the stretching of the radio waves emitted by atoms of hydrogen (the most ubiquitous element in the universe) as they speed away from the edges of the cosmos.

Radio and optical telescopes have a similar design, as they both include a camera and a focusing element that reflects light to generate a clear image. But unlike an optical telescope, which requires an exquisitely precise glass mirror as its focusing element, a radio telescope’s metallic dish can be constructed for about 1/100 th the cost of a similarly-sized optical mirror.

Our group has constructed a small prototype radiotelescope in a groundwater recharge basin behind Brookhaven Lab's steam plant. We’ve started taking images of our own galaxy—the Milky Way— and will continue to do so over the next five years to demonstrate the promise of radio telescopes for cosmology. Since scientists have already explored the structure of the Milky Way in detail using optical telescopes, studying it with radio waves will serve as an excellent test bed for this technique. We’ll also have an opportunity to explore ways to manage the radio frequency interference generated by the weather radar on the Lab site, as well as nearby cellular towers and planes flying overhead.

In all, this Lab-funded project gives us a unique opportunity to demonstrate the feasibility of a future large dark energy project that could explore an even larger volume of the universe than LSST. The cosmic frontier is vast, but we are eager to develop the tools to unravel its secrets.