- Breakthrough: Scientists measure distance to stars on far side of Milky Way for the first time.
- Cutting-edge tech: Very Long Baseline Array (VLBA) used to gauge distance to distant star-forming region.
- Parallax technique: Measures angle change to determine distance, revealing the elusive Scutum Centaurus Arm.
- Dusty challenge: Interstellar dust typically obstructs optical view, but methanol and water molecules provide clarity.
- Astounding result: Distance estimated at 66,000 light-years, surpassing previous parallax record.
The mysterious expanse of our Milky Way, particularly its farthest reaches, has long eluded direct observation. However, a groundbreaking discovery published in Science offers a tantalizing glimpse into our galactic abode’s true form. Using the cutting-edge Very Long Baseline Array (VLBA), a network of ten telescopes spanning North America, scientists have successfully measured the distance to a distant star-forming region known as G007.47+00.05 within the Scutum Centaurus Arm. This achievement not only marks the first-ever measurement of stars on the galaxy’s opposite side but also confirms the existence of the Scutum Centaurus Arm.
The ingenious technique employed, called parallax, relies on tracking the change in angle to the remote region when Earth orbits to opposite sides of the Sun. This angle shift corresponds directly to the distance. Overcoming the challenge posed by interstellar dust, the researchers traced the movements of methanol and water molecules in the distant star-forming region, allowing for precise measurements. The result is nothing short of astounding—a distance of 66,000 light-years, based on observations spanning 2014 to 2015, dwarfing the previous parallax record of 36,000 light-years.
Alberto Sanna, lead author of the study from the Max-Planck Institute for Radio Astronomy (MPIfR) in Germany, aptly likens this achievement to measuring a baseball on the lunar surface. This feat essentially amounts to gauging the distance to an object located on the far side of the galaxy relative to the Sun. This discovery is part of the broader BASSAL survey, which aims to measure distances to star-forming regions across the Milky Way. Ultimately, the project’s aspiration is to reconstruct a face-on view of our galaxy from a staggering million light-years away within the next decade.
Already, these revelations shed light on the intriguing nature of the far side. The Scutum Centaurus Arm, in which this star-forming region resides, was found to possess an unexpected undulating quality, pitching up and down. While the VLBA has been in operation for several decades, it’s only now, with the refinement of the parallax technique, that such a measurement has become possible. The team’s next objective is to map distances to other uncharted regions of the galaxy, with roughly a quarter of it still awaiting exploration.