We watched the video Tom posted on the hub (journey to the edge of the universe) and it really got us thinking about how the universe is expanding and what could be beyond the edges of the visible universe.
For thousands of years, astronomers have been asking basic questions about the size and age of the universe, such as whether or not the universe goes on forever, whether it has an edge and whether or not it has always existed. In 1929, Edwin Hubble made an exciting discovery: he discovered that the universe is expanding. What this means is that the galaxies outside of our own are moving away from us and the ones that are furthest away from us are moving the fastest.
But what are they moving into? According to a video we watched on the BBC, the universe isn’t necessarily expanding into anything, which we found really difficult to get out heads around. The scientist in the video compared the universe’s expansion to the surface of a balloon when you blow it up; if you were to draw dots on the surface of the balloon they would move further and further away from each other as you blew it up. In the same way, the galaxies in our universe are moving further and further away from each other as the universe expands.
The video argues that the universe is everything and that there doesn’t need to be something else for it to expand in to (unlike the balloon, which expands into the air around it.). As the universe expands, more space simply appears. It is created from nothing and will continue to happen without limit. This is hard to imagine because the human mind can’t really process the idea of ‘nothingness’, but the logic behind it made us think it could be true, even if we can’t fully understand it.
This would surely mean that the universe is infinite, which is surprisingly the easiest idea to get your head around compared to the other theories that are out there.
There are two other possibilities we found during our research for what lies beyond the universe, both of which are really difficult to understand.
The first possibility talks about the idea of something called ‘dark flow’. In 2008 (the year we were born!), astronomers discovered that galactic clusters (a structure that consists of hundreds and thousands of galaxies) were all streaming in the same direction at over two million miles per hour. One reason for this could be some sort of massive structure outside the edge of the observable universe exerting gravitational influence and pulling the universe outwards. These structures could be anything from accumulations of matter and energy to some sort of warp in space-time. We just don’t know.
Another option (and we found this the most strange) involves a universe of universes (a multiverse), which would mean that our universe existed in the midst of vast array of other universes. In this case, there would be other parallel universes beyond our universe, and these universes would be able to come into contact with each other, connecting to make a Big Bang like the one that created our universe.
What do you think? Is the universe infinite? Is there anything beyond it? Will it expand forever?