Deep Space and Time

Galaxy Superclusters Spanning millions or hundreds of millions of light years, galaxy superclusters are the biggest objects in the universe. Gravity gives galaxies a tendency to clump together, forming structures that can be relatively small like our own ‘Local Group’ (consisting of three large spiral galaxies (Andromeda, the Milky Way and the Triangulum) and many small dwarf galaxies) or can contain hundreds of these large galaxies. When these clusters themselves cluster together they form superclusters. There’s often a very large cluster at the centre of them (imagine a solar system with groups of galaxies instead of planets and a really big group instead of the Sun). The Local Group is part of the ‘Local Supercluster’.

Gravitational Lensing This is a going to be a bit tricky to explain. Basically, as per something to do with Einstein, large masses (e.g. superclusters or black holes) have a distortion effect on stuff. So if a black hole was between us and something else, like in the picture, it would all look a bit weird. It’s difficult for us in a three- dimensional world to understand this so let’s go down a dimension. Imagine a sheet of rubber or something. It’s pretty flat. When you put something heavy on it, it bends a little. This is what happens to space. Don’t worry, I don’t really understand it either.

Dark Matters Visible matter only makes up a small percentage of the universe (4%, to be exact). There seems to be lots of other stuff, ‘Dark Matter’, that doesn’t emit or reflect any light, even infra-red or ultraviolet. The only way we’ve found it is by firing lasers and seeing that they’re being affected by the gravity of something we can’t see. Scientists reckon that 96% of the universe’s mass is dark matter and dark energy. This is where the dark matter is in the universe (maybe)

= → Black Holes headache As you probably know, black holes are really, really massive things in space that have such strong gravity that even light can’t escape from a certain point. Remember that massive just means it has a lot of mass – it doesn’t mean it’s big; in fact black holes are infinitesimal points and the ‘hole’ you see is just everything inside the event horizon where light can’t escape from. If you want help imagining what infinitesimal means, imagine trying to stuff a whale into a matchbox. An interesting thing about black holes is that when you get near them, time seems to slow down to anyone watching but to you, it seems normal. You probably won’t have time to appreciate this as every atom in your body is stretched beyond belief and in an instant you are in the matchbox with the whale and everything else that the black hole’s sucked up. Some reckon you go to a parallel universe… → = headache

The End of the Universe… Scientists believe that there are different ways for universes to end. The ‘Big Rip’ where dark energy wins over everything else and we all die Then there’s the ‘Big Chill’ in which the universe keeps on expanding forever even when the stars become extinct. In this case, we all die. Our universe is probably going to end in the ‘Big Crunch’. This is where the universe doesn’t have enough momentum to keep on expanding, gravity wins and it all returns to the singularity of the Big Bang. When this happens, we all die. So we’re all going to die. What a nice thought. It’s probably in about 20,000,000,000 years’ time, though so don’t worry too much. There are some who say that the Big Crunch could lead to another Big Bang and a new universe, maybe different to this one or maybe the same. Maybe there’ll be a new Earth. Just maybe, in 35,000,000,000 years, there’ll be another me speaking to another Space Club in another Kesgrave High School…