Mapping out an entire galaxy is easier said than done, but a team of scientists claims to have produced the clearest map of the Milky Way yet. In the process, they discovered that our solar system may be bigger than previously thought.
It has long been assumed that the Milky Way galaxy is shaped like a disk. While the galaxy's exact structure is still highly debated, the consensus is that the galaxy has four major arms of stars, gas and dust that spiral out from its center.
New stars are often born from the dust and gas in those star-filled arms. However, the dust can cover stars that scientists use as a starting point for measuring the distance, making the process of mapping the galaxy complicated.
Our solar system is situated at the edge of what is known as the Local Arm or the Orion Spur. Neighboring arms are called Scutum-Centaurus, Perseus and Sagittarius. The Local Arm, which appears like a separate piece of arm, is said to be smaller than Perseus.
Bigger Than Past Calculations
Now, in the new study, scientists from the Purple Mountain Observatory in China reveal that the Local Arm may actually be just as big as the others. Historically, the Local Arm did not get "much respect," experts said.
"People thought it was just a tiny little thing," said Mark Reid, co-author of the new study and an astronomer from the Harvard-Smithsonian Center for Astrophysics.
With the help of a series of radio telescopes in New Mexico known as the Very Long Baseline Array (VLBA), scientists managed to create extremely precise measurements of gas clouds in the Milky Way's arms. They also applied a star-measuring trigonometry method called paralax to measure the distances.
Astronomer Ye Xu, one of the researchers in the study, said radio telescopes can pierce through the cosmic plane to large star-forming regions that mark the spiral structure. He said optical wavelengths will be concealed by the dust.
In the end, the research team found that the Milky Way is not a spiral with distinct and clear-cut arms, but one that contains many subtle spurs and different branches.
There is also a spur linking together the Sagittarius and Local Arms. Furthermore, the Orion Spur may actually not be a spur at all, but may be similar to other spectacular arms in the Milky Way.
Details of the report are published in the journal Science Advances.
Photo: European Southern Observatory | Flickr