Scientists released new research suggesting that the solar system's host galaxy, the Milky Way, is still growing. To prove this hypothesis, scientists had to look at other similar galaxies first.
They say if we could look at the Milky Way in millions of years, we would be able to see how much bigger it is.
Growing Galaxy
Currently, the Milky Way galaxy has a diameter of 100,000 light-years. It consists of around several hundred billion stars along with large quantities of gas and dust. Researchers saw that it would be challenging to observe the Milky Way growing since the solar system sits in one of its arms.
Researchers wanted to see how the formation of stars in the edge of the Milky Way's disk affected the dimensions of the galaxy. Instead of observing the Milky Way, scientists observed nearby spiral galaxy. They singled out the galaxy NGC 4565, which also has a diameter of 100,000 light-years and is 30 to 50 million light-years away from Earth.
For the study, scientists used space-based and ground-based telescopes to monitor the edges of the NGC 4565. For the optical research, they used ground-based Sloan Digital Sky Survey telescope. They also used two space-based telescopes GALEX and Spitzer, which provided near-UV and near-infrared data. This data let them see the colors and movements of the stars they were observing.
Speed Of Sound
Researchers observed that the light coming from the edges of the spiral was coming from young blue stars. They tracked the vertical movement of the stars to see how quickly they would move from the point where they formed and the speed at which the galaxy is growing.
They were able to determine that galaxies similar to the Milky Way are increasing in size at about 550 yards per second. This would be fast enough to travel from New York to London in three hours.
Researcher Cristina Martinez-Lombilla, from the Instituto de Astrofisica de Canarias in Spain, says that in order to observe the change, time travel would be needed. If the galaxies were observed in 3 billion years, they would be 5 percent larger than today.
The galaxies are growing at a speed of about 1,100 miles per hour, that would be about 1.4 times the speed of sound on Earth.
Scientists say that this growth in the Milky Way could be hampered by the collision with another spiral galaxy, the Andromeda. This would create a larger galaxy after the two merge.
