Consider a coin spinning on a table. It can land on its heads or its tails, but it cannot be defined as "heads" or "tails" until it stops spinning and falls to one side. A coin has a chance of landing on its head or its tail, so if enough coins are spun in exactly the same way, half should land on heads and the other half on tails. In the same way, half of the oscillating particles in the early universe should have decayed as matter and the other half as antimatter.
However, if a special kind of marble rolled across a table of spinning coins and caused every coin it hit to land on its head, it would disrupt the whole system. There would be more heads than tails. In the same way, some unknown mechanism could have interfered with the oscillating particles to cause a slight majority of them to decay as matter.
Physicists may find hints as to what this process might be by studying the subtle differences in the behaviour of matter and antimatter particles created in high-energy proton collisions at the Large Hadron Collider. Studying this imbalance could help scientists paint a clearer picture of why our universe is matter-filled. You look at how matter and antimatter behaved in the ridiculously high energy environment straight after the Big Bang, and see if there's any oddness that could account for the tiny excess of matter needed to explain all the matter that's here today.
And the best way to recreate the high energy big bang environment is by smashing particles together at near light speed in a particle accelerator like the Large Hadron Collider at CERN and seeing what falls out. The most straightforward way to end up with slightly more matter than antimatter is to have processes that produce them a bit unevenly. With high-energy photons out of contention, the strongest candidates for a process that gives slightly more matter than antimatter are a couple of incredibly heavy particles of matter — the heavy neutrino and the beauty quark.
Beauty is its stage name — it also goes by "bottom quark", a name still favoured by older physicists, the British and nine-year-olds. Like all super-heavy particles, these bits of matter are unstable. This means they can only exist in incredibly high-energy environments, and only for an incredibly short time. They then quickly decay through a series of steps into smaller, more-stable particles and antiparticles.
The suspicion is that the antimatter versions of these superheavy particles decay slightly differently from the matter versions. That's just 10 times more than the amount of leftover matter needed post-Big Bang to give us our universe — a pretty good result in this vast field of unknowns.
The amount of excess matter beauty quarks could account for is a little harder to predict because it relies on interactions with a new force or forces that haven't actually been discovered. Theories are great, but science is built on evidence.
Recreating faux-Big Bang conditions that could form either beauty quarks or heavy neutrinos is the focus of particle accelerators the world over. Symmetry is big in physics. And asymmetric behaviour at this scale doesn't fit with the mathematical Standard Model, so finding it wouldn't just help explain why the universe isn't a sea of light, it would mean an edit or rewrite of the Standard Model itself. And that would look great on any physicist's CV. To hear more about big mysteries of the universe like this one, listen to this Saturday's Science Show with Robyn Williams: To infinity and beyond.
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Key points: Equal amounts of matter and antimatter were made in the Big Bang These should have destroyed each other But some how we ended up with left over matter Physicists are looking for the cause of this by smashing high speed particles together. More on:. Top Stories A former cop calls it 'the number one threat to society'. For example, when an electron meets its antiparticle — the positron — the emitted energy is most likely in the form of electromagnetic radiation.
The frequency of the light from electron-positron annihilation is too high for our eyes to see, but gamma-ray detectors can identify it. For high-energy collisions, or those between nonfundamental particles like the proton, the story is slightly more complicated. Protons are actually composed of smaller particles called quarks, so if you collide a proton and an antiproton with enough energy, you, in fact, create a quark-antiquark collision.
The interaction of matter and antimatter can release the energy from both of these forces in the form of exotic particles. In fact, the much-sought-after Higgs boson is one form of weak-force energy.
One way to increase the chances that a matter-antimatter collision yields non-electromagnetic energy is to accelerate the particles and antiparticles to extreme speeds and thus high energies. Arp 91 showcases a cosmic union in deep space.
Neutron stars: A cosmic gold mine. What would this cyclic model of the universe mean for the Big Bang? Tests of general relativity with gravitational waves can go awry. Where did the universe's antimatter go? Scientists inch closer to solving the mystery. Did life on Earth come from outer space? A starry sense of wonder can combat fears and doubts about science. Space is the place for impossible molecules. Cosmos: Origin and Fate of the Universe. Astronomy's Moon Globe.
Galaxies by David Eicher. Astronomy Puzzles. Jon Lomberg Milky Way Posters. Astronomy for Kids.
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