‘The Wave is Waving’: Harvard Astronomers Discover Radcliffe Wave’s Oscillation

An international group of astronomers led by a Harvard Ph.D. student reported their discovery that the Radcliffe Wave — a 9,000 light-year-long gaseous structure in the Milky Way — moves in an oscillating pattern in a paper published in Nature Tuesday morning.

The team, consisting of Center for Astrophysics researcher Catherine Zucker and professor Alyssa A. Goodman, was led by Ralf Konietzka, a Ph.D. student at Harvard’s Graduate School of Arts and Sciences.

Researchers had previously known that the Wave looked like a curved “chain of gaseous clouds in our Sun’s backyard.” However, Konietzka’s team discovered that it “not only looks like a wave, but also moves like one,” according to the report.

The Radcliffe Wave was named in honor of the Harvard Radcliffe Institute in 2020, when its undulation was discovered by a fellow affiliated with the institute at the time.

This new finding was facilitated by data from the Gaia spacecraft, which allowed astronomers to observe the Wave’s three-dimensional motion for the first time ever.

In collaboration with the Harvard Data Science Initiative, Konietzka and his research group analyzed and combined novel data sets from Gaia — a space observatory of the European Space Agency that orbits Earth from a distance of around one and a half million kilometers. In doing so, they observed that the Radcliffe Wave is producing “clusters of baby stars” near the Milky Way’s spiral arm, which is close to the Earth.

Konietzka compared the movement of the baby stars located on the Radcliffe Wave to that of fans in a stadium doing the wave at a baseball game.

“But there are no humans, there are baby stars, which are basically jumping up and falling back,” said Konietzka.

Their gradual movement can be detected from hundreds of light-years away.

“The oscillation period of the wave-like structure is 100 million years,” said Goodman, emphasizing the substantial technology needed to detect movement from such a distance away.

The researchers postulate that this discovery could have far-reaching effects for the understanding of astronomical phenomena beyond the Radcliffe Wave.

“We also could use the Wave — and this is already in the paper — to measure the amount of dark matter around the solar system,” Konietzka said.

“This has implications not just for the Milky Way, but for how galaxies work,” Goodman explained.

He highlighted the many possible research directions that could stem from these new findings in subsequent years.

“It’s one of these new things where five years from now we’ll see what happens with this discovery, but it’s just something that people didn’t know about before,” Goodman added. “And that’s honestly, to us anyway, the most exciting part of this.”

Konietzka noted how mock images that depict the Milky Way are theoretical and cannot represent its actual structure.

Snapshots of this larger picture, as illustrated in the Radcliffe Wave, offer insights into the rest of the picture and the technical methods needed to explore it.

“Now we have not just a picture, but a movie of what’s going on,” Goodman described.

Going forward, the researchers aim to push the limits of these tools for further space exploration.

“The question is, how much farther can we go with the 3D depth mapping and measuring of these motions?” Goodman asked.

—Staff writer Elizabeth Peng can be reached at elizabeth.peng@thecrimson.com.

—Staff writer Nicholas J. Frumkin can be reached at nicholas.frumkin@thecrimson.com.