Gravitational bending reveals oldest spiral galaxy on record

A group of astronomers have uncovered what is likely the oldest spiral galaxy known to science.
By Jose Jefferies | Nov 08, 2017
By studying gravity's light-bending properties, an international team of researchers have discovered what could be the oldest spiral galaxy ever found.

While many people associate galaxies with the Milky Way's spiral shape, most do not appear in that way. In fact, galaxies often look like giant, messy blobs without any distinct shape. As a result, scientists are not quite sure what conditions are needed to form spiral arms. However, the newly discovered formation could help shed light on that conundrum.

"Detailed observations of spiral galaxies at high redshift will enable meaningful investigations into these physical processes that remain elusive in simulations," the authors wrote in their paper, according to Gizmodo.

In the deep reaches of space, gravity bends the path of light traveling past large star clusters. Researchers look for such irregularitieswhen analyzing distant systems, and thattechnique helped the team in the recent study discover the ancient spiral system, A1689B11. They then used the Hawaiian Gemini North telescope's "Near-infrared Integral-Field Spectrograph" tool to gather a year's worth of measurements on the galaxies's properties.

That revealed the disk-shaped galaxy likely came about roughly 2.6 billion years after the universe first formed. As the universe is thought to have formed 14 billion years ago, that dating easily makesA1689B11 the oldest spiral system on record.

While there is a chance the image is simply merging galaxies rather than a distinct spiral shape, the team plans to continue looking at the formation. Finding a spiral shape that old could help answer a lot of questions about the different star structures, and may shed light on both our own galaxy as well as the universe itself.

"[S]piral galaxies are exceptionally rare in the early universe, and this discovery opens the door to investigating how galaxies transition from highly chaotic, turbulent discs to tranquil, thin discs like those of our own Milky Way galaxy," said study co-author Renyue Cen, a researcher at Princeton University, according to Phys.org.

The team hopes that NASA's James Webb Space Telescope -- which is set to launch in 2019 -- will build on this new study by bringing more ancient spiral systems to light.

The findings are published in the Astrophysical Journal.

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