While we are used to much of our tech getting smaller, telescopes seem to be embracing the philosophy of bigger is better. The HERA (Hydrogen Epoch of Reionization Array) radio telescope is among those massive arrays peeking not only to far distances, but also through billions of years.
No, HERA is not a time machine (at least not in the Back to the Future sense) but given the way that light works, these large telescopes are looking into the past. Since light travels at a constant rate, we can measure distance by how long it takes for that light to travel to us (measured in light years). So, if we’re looking at a star 10 billion light years away, we are seeing that star as it existed 10 billion years ago.
The HERA array consists of 240 antennas — and thanks to a $5.8 million grant from the Gordon and Betty Moore Foundation — it will be growing by an additional 110 to bring its total to 350 antennas. This boost in power will add another 50 percent to its collection area. Each antenna is approximately the size of a city bus, 14 meters (42 feet). Sitting side by side, the completed array will measure more than ten football fields at 57,000 square meters (over 615,000 square feet).
The full array is expected to be operational by September of 2019.
One of the benefits of expanding on the array is that we will be able to peer even further into the universe’s past. Scientists will be able to see back to the time by about 13 billion years — when there weren’t even enough stars to form galaxies. The main goal of the team using HERA is to look at the massive objects from the very beginning of the universe and determine how those objects affected their environments. This can help us get closer to developing a complete picture of the universe’s timeline.
The interaction between these objects and their surroundings could also reveal how the universe began to clump together and form the earliest celestial objects. After the Big Bang, the history of celestial objects begins with what scientists call the Epoch of Reionization.
HERA is set to pick up the wavelength of light emitted from hydrogen atoms. According to Anna Frebel, an assistant professor of physics at MIT, being able to map the ionization of hydrogen will tell scientists how long this process took, and how big these areas of reionized hydrogen were. These areas will look like empty bubbles in pictures taken with HERA, but will likely be bright points of light to even more powerful telescopes like the James Webb. This will allow scientists to cross-reference data between the two telescopes.
The story of the universe is not an easy one to tell in full, but each new development in space observation is getting us closer fully understanding the complete biography of everything.