Space is what’s above the atmosphere. It’s called that because it has far fewer molecules, with lots of empty space between them.
Have you ever wondered what it would be like to travel to outer space and then keep going? What would you find? Scientists are able to explain a lot of what you’d see. But there are some things we just don’t know yet, like whether space just goes on forever and forever.
Planets, stars and galaxies:
At the beginning of your trip through space, you might recognize some of the sights. The Earth is part of a group of planets that orbit the Sun with some orbiting asteroids and comets mixed in, too.
You might know that the Sun is actually just an average star, and looks bigger and brighter than the other stars because it is closer to us. To get to the next nearest star, you would have to travel through trillions of miles of space. If you could ride on the fastest space probe NASA has ever made, it would still take you a long time (probably thousands of years) to get there.
If stars are like houses, then galaxies are like cities. Scientists estimate there are 100 billion stars in Earth’s galaxy. If you could zoom out, way beyond Earth’s galaxy, those 100 billion stars would blend together the way lights of city buildings do when viewed from an airplane.
If you could watch for long enough, over millions of years, it would look like new space is gradually being added between all the galaxies. You can visualize this by imagining tiny dots on a deflated balloon and then thinking about blowing it up. The dots would keep moving farther apart, just like the galaxies are.
Is there an end ?
If you could keep going out, would you just keep passing by galaxies forever? Are there an infinite number of galaxies in every direction? Or does the whole thing eventually end? And if it does end, what does it end with?
In either case, you could never get to the end of the universe or space. Scientists now consider it unlikely the universe has an end – a region where the galaxies stop or where there would be a barrier of some kind marking the end of space.
But nobody knows for sure. How to answer this question will need to be figured out by a future scientist.