It can be difficult to understand all the very big and very small things. Ron Koeberer/Millennium Images, UK
Imagine taking off in a spaceship that can travel at the speed of light. You can't go far. It also takes 100,000 years to reach the other side of the Milky Way. Our nearest galactic neighbor, Andromeda, is another 2.5 million years away. And beyond that, there are about 2 trillion galaxies.
The vastness of the universe is beyond comprehension. Yet, at a fundamental level, it is made up of tiny particles. “It's a bit foreign, whether it's small or very large,” says the particle physicist. Alan Barr at Oxford University. “I don't think you can really understand it, you just get used to it.”
Still, some sense of scale is necessary to understand how reality works.
Let's start with the Cosmic Microwave Background (CMB). This is radiation released 380,000 years after the Big Bang. “The largest scale we have measured is a feature of the CMB,” says astrophysicist Pedro Ferreira at the University of Oxford. Thanks to these, the diameter of the observable universe has been estimated to be 93 billion light years.
At the other end of the scale, the smallest entities are fundamental particles like quarks. However, quantum physics depicts these as dimensionless points in a quantum field, with no size at all. So what is the shortest distance? The best we can do is the so-called Planck length, which is approximately…
Source: www.newscientist.com
