Andromeda Galaxy Is The Same Size As Milky Way


Existing information about the spiral Andromeda galaxy may not be accurate anymore. A new study has reduced the size of Milky Way's neighboring galaxy.

In a pre-published study, Astronomers from the International Centre for Radio Astronomy Research based in Australia revealed that they used a new technique for measuring the mass of galaxies and found that the Andromeda Galaxy is similar in size to the Milky Way.

The technique, which involved observation of escape velocity and dynamical mass modeling of stars within the galaxy, found that the mass of Andromeda is roughly 800 billion times than the mass of the sun. The sun has a mass that is comparable to the Milky Way.

To measure the dynamical mass of the galaxy, the astronomers measured the rotation curve, velocity dispersion, dynamical model, and the tidal stream orbit modeling of the Andromeda.The Andromeda shines 25 percent brighter and has twice as many stars as the Milky Way. On a clear night away from city lights, the galaxy can be seen next to a bright band of the Milky Way.

Need For Speed

"When a rocket is launched into space, it is thrown out with a speed of 11 km/s to overcome the Earth's gravitational pull," says Dr. Prajwal Kafle from The University of Western Australia branch of ICRAR.

"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," adds Kafle.

Early research and observations pegged Andromeda's size as two to three times bigger than the Milky Way.

Following this latest discovery, new simulations are needed on what could probably happen if the two galaxies collide. In the past, it was said that due to its size, Andromeda would devour and make a cosmic snack out of the Milky Way.

It is believed, however, that the Andromeda is being sucked by Milky Way's gravitational pull at a speed of 250,000 miles per hour and collision is due in 4 billion years.

Formed In A Crash Of Stars

Meanwhile, a separate new study by French and Chinese astronomers concluded that Andromeda was formed after star systems, one much bigger than the other, collided with each other between 1.8 billion to three billion years ago.

The astronomers led by Francois Hammer of the Paris Observatory reportedly simulated the reconstruction of Andromeda by using the most powerful available computers in France to analyze massive information on the galaxy and its stars.

The Milky Way and the Andromeda are 2.5 million light-years apart. The two galaxies are the two largest in the Local Group of over 30 galaxies. In the big span of the space, astronomers say it will take an estimate of two million years to reach Andromeda.

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