Data from the Sloan Digital Sky Observatory and Gaia spacecraft show that a collision with another galaxy produces the oddly distorted shape of the Milky Way.
Researchers know very little about the curved shape of the Milky Way galaxy due to the difficulty of studying the galaxy from within, but they have observed many similar distortions in around 50 to 70 spiral galaxies. The new results show that the Milky Way is distorted by the interaction with another galaxy, which takes place quite recently compared to the 13.7 billion year old age of the universe. According to the researchers, about 3 billion years ago, a satellite galaxy so close to the Milky Way that it produced a ripple effect could still be observed in the stars of our galaxy.
“Our common visualization of a spiral galaxy is a flat disk, rotating evenly around its center,” said senior researcher Xinlun Cheng of the University of Virginia. “But the reality is much more complicated.”
It is difficult for scientists to map the curved shape of the Milky Way galaxy because the Earth is located deep inside the galaxy. Even though our spacecraft takes off from the planet, in spatial terms the majority of ships are still inside the bubble formed by the Sun around the Earth. Instead, Cheng’s team learned this by studying the movement and position of stars in the Milky Way. The new results show that every 440 million years, the distortion of the galaxy’s disk propagates.
“Imagine you are watching a soccer game and the crowd starts to make waves,” Cheng explained. “All you have to do is get up and sit down, but the effect is that the waves will spread across the stadium. The same goes for the warp galaxy, the stars are moving high. down, but the waves are traveling. ” Galaxy “.
The team gathered the information using the Apache Nose Observatory’s Galactic Evolution Experiment (APOGEE), which has tracked hundreds of thousands of stars in the Milky Way over the past decade. APOGEE collects stellar spectra, or wavelengths of light emitted by a star, during the investigation. Later, astronomers added observations from the European Space Agency (ESA) Gaia satellite, which measures distance to stars in the Milky Way. By combining the two data sources, they were able to map in 3D the stars of the Milky Way with their speed and composition.
The study could help astronomers create a more accurate model for the Milky Way’s collision with the Andromeda galaxy (M31) about 4.5 billion years old. The study’s authors announced the results at the American Astronomical Association’s webinar that took place Jan. 11-15.
