How does our Milky Way appear? You might be surprised to learn that, for the most part, we don’t truly know for sure. But a recent finding could finally make the form of the galaxy our home known.
This astounding discovery, which was reported in the journal Science, is that researchers have for the first time calculated the distance to a collection of stars on the other side of the galaxy. We can now start tracing the Milky Way’s appearance.
The researchers utilized the Very Long Baseline Array (VLBA), a collection of ten telescopes located throughout North America, to calculate the separation between themselves and the G007.47+00.05. It was measured in our galaxy’s Scutum Centaurus Arm. It’s wonderful that this finding truly establishes the existence of arms.
By observing the change in angle to the distant area while Earth was on opposite sides of the Sun, a method known as parallax allowed them to calculate the distance to the stars. The distance increases as the angle decreases.
Due to the interstellar dust that obstructs optical light, seeing the far side is challenging. But in this study, the researchers were able to follow the movements of water and methanol molecules in the far-off star-forming area.
The outcome? Based on observations from 2014 and 2015, they calculated the distance to be 66,000 light-years. The previous record for parallax was only 36,000 light-years, which is quite little.
According to Alberto Sanna, the study’s principal author from Germany’s Max-Planck Institute for Radio Astronomy (MPIfR), “this measurement equates to being able to measure a baseball on the lunar surface.”
In essence, we are calculating the distance to a target that is situated on the other side of the galaxy from the Sun.
The finding was produced as a result of a larger survey known as BASSAL. In order to rebuild a face-on image of our galaxy from a million light-years distant in at least 10 years, the project’s primary objective is to estimate distances to star-forming areas throughout the Milky Way.
We can already see from these data that the far side is quite fascinating. For instance, it was discovered that the arm in which this star-forming zone is located is not completely flat but instead pitches up and down.
The parallax approach has just recently been improved, despite the fact that the VLBA has been around for a few decades. With nearly a fourth of the galaxy still unexplored, the team now wants to map the distances to neighboring spheres.