YOUNGSTOWN -  A Youngstown State University professor is part of a massive project to create a 3-D map of the universe.

Astronomy professor John Feldmeier is one of 100 scientists taking part in HEDTEX, the Hobby-Eberly Telescope Dark Energy Experiment.

Feldmeier is Chief Imaging Scientist for HEDTEX and has been part of the collaboration since 2011.

The experiment will map of 2.5 million galaxies to help astronomers understand how and why the expansion of the universe is speeding up over time.

Feldmeier, who earned a PhD from Penn State University and joined the YSU faculty in 2006, describes himself as an observational astronomer who studies galaxies, galaxy clusters, and the stars between the galaxies.

"HETDEX represents the coming together of many astronomers and institutions to conduct the first major study of how dark energy changes over time," said Taft Armandroff, director of The University of Texas at Austin's McDonald Observatory.

The survey began in January 2017 on the 10-meter Hobby-Eberly Telescope (HET) at McDonald Observatory. Today, the survey is 38% complete.

The survey works by aiming the telescope at two regions of the sky near the Big Dipper and Orion. For each pointing, the telescope records around 32,000 spectra, capturing the cosmic fingerprint of the light from every object within the telescope's field of view.

"It's actually a little mind-blowing, how much information is captured in this," said team member Gary Hill.

These spectra are recorded via 32,000 optical fibers that feed into more than 100 instruments working together as one. This assembly is called VIRUS, the Visible Integral-field Replicable Unit Spectrograph. It's a massive machine made up of dozens of copies of an instrument working together for efficiency. VIRUS was designed and built especially for HETDEX.

This makes VIRUS one of the most advanced astronomical instruments in the world.

HETDEX is a blind survey, meaning that rather than pointing at specific targets, it records everything over a specific patch of sky. Then scientists go through the data to sift out objects they want to study.

To make the map needed for the dark energy project, they are combing through a billion spectra looking for examples of a specific type of galaxy. These galaxies range in distances from 10 billion to 11.7 billion light-years away, so they represent an epoch when the universe was only a few billion years old.

Their spectra carry information about how fast the galaxies are moving away from us because of the expansion of the universe. That will allow astronomers to determine how the rate at which the universe expands has changed over the eons, which is key to determining the nature of dark energy.

The HETDEX team expects to complete its observations by December 2023. In total, the completed survey will include 1 billion spectra, "the largest ever spectral survey by far," Gebhardt said. These data are processed and stored at UT Austin's Texas Advanced Computing Center (TACC), one of the top supercomputing centers in the world.

Meanwhile, many astronomers are using the data already collected to attack a number of other astronomical mysteries. Several are on the verge of publishing their research.

Among them is UT professor Keith Hawkins. He has made use of the survey's spectra of about 100,000 stars in our own Milky Way galaxy. Though these stars were not the main quarry for HETDEX, they were captured by the blind survey. "As my grandfather used to say, 'One man's trash is another man's treasure,'" he said.

Hawkins is using these spectra to study the stars' contents, sizes, temperatures and motions to trace how the different parts of our galaxy came together. His research paper on this work will be published soon. Other astronomers are preparing to publish research on white dwarfs and nearby galaxies for which they used HETDEX data.