Andromeda Galaxy, Milky Way Galaxy’s closest neighbor, turns out to be smaller than what researchers thought. A new tool for measuring the mass of galaxies reveals that Andromeda is not two or three times bigger than Milky away – they are just the same size.
True Size of Andromeda Galaxy
Australian astronomers revealed their findings after using a new technique in measuring the size of galaxies. The study published in the Monthly Notices of the Royal Astronomical Society reveals that Andromeda’s size is roughly the same as the Milky Way – 800 billion times the mass of the sun.
The mass of a galaxy is determined using the amount of dark matter. Stars only make up a small part of the galaxy. It’s possible to measure dark matter because it holds stars in their orbit.
Dr. Prajwal Kafle of the University of Western Australia reveals how they came up with the new computation of Andromeda’s size in a press release .
“When a rocket is launched into space, it is thrown out with a speed of 11km/s to overcome the Earth’s gravitational pull,” he said.
“Our home galaxy, the Milky Way, is over a trillion times heavier than our tiny planet Earth so to escape its gravitational pull we have to launch with a speed of 550km/s.”
“We used this technique to tie down the mass of Andromeda.”
Kafle claims that the reason behind the inaccurate measurement of the size of Andromeda may have been the fact that scientists overestimated the amount of dark matter in the galaxy.
By examining the orbits of the high-speed stars, Kafle’s team discovered that dark matter in Andromeda galaxy is only a third of what prior studies uncovered.
This is not the first time Kafle studied the mass of galaxies. In 2014, he also used the escape velocities of objects inside the Milky Way to measure its mass. His findings were similar to what happened to the estimates for Andromeda’s mass – the amount of dark matter was overestimated.
Immense Collision
The Andromeda Galaxy may be home to a pulsar, the dense remnant of a dead star that is highly magnetized & spinning: https://t.co/KYVItyU1xT pic.twitter.com/m2J9ceVu1o
— NASA (@NASA) March 23, 2017
Prior studies devoted to space revealed that there will be an imminent collision between the Milky Way Galaxy and the Andromeda Galaxy. The neighboring galaxy may be 2 million lightyears away.
This new data suggests that in 4 billion years, Andromeda might not engulf Milk Way. This information will also change estimates and data about the impending collision that will merge the two galaxies into one.
With the new findings, it seems like Andromeda will not overpower Milky Way, but researchers have no way of knowing as yet. A simulation needs to be done to see what will happen when the collision occurs.
