Fasten your seat belts and grab the popcorn, because you have a fascinating cosmic spectacle. And you will become a direct participant in the events. In the next 5 billion years, the Milky Way will crash into the Andromeda galaxy. This is our closest neighbor, distant by 2.5 million light years.
What happens when they collide? It all depends on who weighs more. We used to believe that Andromeda is 3-4 times larger than the Milky Way. This is written in all textbooks. But recent research suggests that the data needs to be updated. It turns out that they are almost equal.
Dark matter will show the way
A smaller mass estimate does not mean that the galaxy accommodates fewer stars. Instead, scientists reduce the amount of supposed dark matter. This is a mysterious invisible material in galactic weight. No one knows what it is, but thanks to the American scientist Vera Rubin, we are convinced that it exists.
It was Vera Rubin in the 1970s. established the existence of dark matter. She managed to find out that Andromeda’s observed objects are not enough to force gravity to affect the system. In fact, we see only 10% of the galaxy, and the rest is a mysterious substance.
Escape from Andromeda
To determine the galactic weight, you need to calculate how fast you need to go to avoid gravitational aggression. The higher the speed, the greater the force of attraction, and this increases the weight. To escape from the Milky Way requires a speed of 550 km / s, which means the galaxy weighs 800 billion times more than the Sun. The weight of Andromeda is about the same.
What is dark matter?
The new assessment changes our understanding of how the neighbor was formed, as well as the principles of its development and contact with other galaxies. It also allows you to look at our galaxy from the side.
Do we need to worry? The question is slightly controversial, because it is unlikely that we will manage to celebrate our 5 billionth birthday. So far, nothing threatens humanity.