Introduction:
At some point in the future, life on Earth has to end. Humans will eventually evolve into something else and colonize other planets. Or maybe they'll send a probe back to Earth to discover whether it's possible for humans to leave our home galaxy? Hopefully, it won't take too long for us to find out.
The Milky Way galaxy is a fairly old system, having formed over 13 billion years ago. The current rate at which the Sun is moving toward the center of this galaxy is considered to be significant according to astronomers who have collected data since the 1800s. It's expected that within 50 million years or so, our Sun will come close enough to the center of our galaxy for it to begin exerting a significant gravitational pull on Earth and its moon.
Will humans ever leave the Milky Way?
Humans are the most adaptable species on Earth, and they're likely to be around for a long time.
Humans have already survived mass extinctions and even nuclear warfare. In the future, we may even start to spread out of our home galaxy and into other galaxies. But what about when we leave? Will humans ever leave the Milky Way?
The Milky Way is a spiral galaxy, meaning that it's shaped like a bar or a doughnut. The Sun sits at one end of this bar-shaped galaxy, with Earth at its other end. The Milky Way has about 200 billion stars in it, and it's so big that if you could see it from space, you would see it as an ellipse that extends past the edge of our solar system (and your telescope).
I get asked this question a lot. Is it possible that humans will ever leave the Milky Way galaxy?
The short answer is: no.
It's a great question, and it's one that I've been thinking about a lot lately. It's an interesting problem because it combines a bunch of different things:
the physics of how planets form and evolve (which are different for gas giants and terrestrial planets)
the physics of how stars evolve and die (which are different for stars like our Sun and stars like our Sun)
the biology of how life evolves on planets (which is different for planets with atmospheres, like Earth and Venus, versus planets without atmospheres like Mars)
the psychology of how people think about space travel (which is different for people who are interested in space travel versus people who aren't).
Humans are not going to leave the Milky Way any time soon. The Milky Way is an important part of our solar system and we have no reason to move into another galaxy.
There are plenty of reasons why we should stay here. We need to protect our home from asteroids, comets, and other space debris that could destroy Earth. We also need to protect ourselves from the harmful radiation that comes from space, which would be deadly if it hit us. We can't do this if we're in another galaxy.
The Milky Way is also a part of our cultural heritage - it's what makes us human and gives us so much joy! It's important for our survival as well as being an integral part of who we are as a species."
Conclusion:
In order to leave the Milky Way, humans would need to propel a spacecraft at immense speeds for thousands or even millions of years. The closer a spacecraft gets to the speed of light, the more energy it takes to accelerate it. A spacecraft starting from Earth will never reach the speed of light... And yet, we know that there are billions of galaxies outside our own, some with expanding superclusters that may push us beyond our galaxy's edge completely.