Living in the Cosmos

On Earth, all of our home, there are many different types of life. From us, humans, to bacteria to trees to fungi, life is all around us. The interesting thing about life on earth is that it all comes from a similar beginning. All life on Earth that we know of is a carbon based life form, or organic. According to evolution, all life today would have started from a single celled organism, millions of years ago, which through genetic mutations eventually changed into all the organisms around us today, including you and I.

This evolution of life here on Earth has inspired a search for life on other planets around the galaxy. You may have heard of planets which fall in the so called "Goldilocks Zone". This means the planet is the perfect distance away in its orbit from its star that the temperature and conditions would be similar to those of Earth, and could theoretically harbour life similar to that of our own planet. Most of the search for life in this field of astrobiology is focused on the search of carbon based life, and most of what you hear about in the news about the possibility for life in the universe will be something about carbon based life specifically. 

This makes sense why it happens, we are curious about other life like us, and the possibility of other humans and intelligent life with whom we could communicate. It is a logical place to start, since the only life we know of is carbon based, why shouldn't we look for other life like it. To me, this point of view is understandable, but somewhat closed minded. 

We only know of one type of life, life like us. So as far as we know this is all that exists. But what is to say there isn't life of many different kinds, most of which is probably nothing like us. Take a minute and try to think about how big the universe is, how immensely large it really is. Think about the possibility of it being infinite, and truly go on forever. Never ending. Its a tough thing to do because our brains aren't suited to think of such things, but still give it a chance. Now think of the possibilities of life within this infinite universe. If the universe is truly infinite, it never reaches its end so anything you could ever think of would have to exist somewhere in the universe, because everything is less than infinity. This is a tough concept to grasp but bear with me. 

If you're thinking of every possibility in infinity, there are probably a couple types of life that don't exist here. Not just different species, but totally different types of life. They could have a totally different elemental structure, they could be larger than our entire planet, there really are and endless number of possibilities of what really could be like. This isn't the easiest thing, but I really encourage you to think about what might be out there. It can be cool to see what your brain can come up with, and thinking about if the universe is infinite and what you think up may actually exist is very exciting. 

There is an important difference here to make between thinking the universe is infinite and what it actually is. Right now, we know generally how old we think the universe is, at least how far we can see so a general sense of scale, and other general ideas about the immensity of the cosmos, but we really can't know. The universe is just too big to see the end of it, and possibly we never will. So when I say the life form you think about could exist at some point, it could very well exist but we may never know if it does or doesn't. Thinking in terms of infinity can be powerful, but I caution at trusting its conclusions, they are all only possibilities.

Particles of Life - Part 3

So far, we have seen particles involved with 2 parts of our universe; those of matter and those of energy. The last types of particles we will talk about are those of the fundamental forces in our world. To do this we need to know what the fundamental forces are. There are 4 of them in total: gravity, electromagnetism, strong nuclear force and the weak nuclear force.

First, we have already looked at a form of electromagnetism, coming from photons. Photons are the disruption in an electromagnetic field. The force of electromagnetism is transferred through these electromagnetic fields, so when there is a disturbance in this field which results in a force and an energy change, which is why a photon is released.

The strong nuclear force is the force which holds the quarks together so they can form neutrons and protons in the centre of an atom. This force is transferred by a particle known as a gluon, which does exactly like it sounds like it would. It basically glues the quarks together through the strong force. The Large Hadron Collider, at CERN in Switzerland, is the  largest particle accelerator in the world to date. Part of what the LHC has done is observe quark gluon plasma, which is basically this interaction between quarks with the strong force.

The weak nuclear force is able to change the flavour of quarks and other particles spins through the emission of bosons. This may not seem like something that comes up very often, but it is a cool process. The particles are called W and Z bosons and what happens is when a particle, such as a quark, starts undergoing a weak decay, one of these bosons is released and through this emission the quarks properties can change. For example an up quark can be made when a down quark releases a W boson, which is then converted into other particles which we will discuss at another time.

Finally, we all know about gravity. Its what keeps us on the ground. This is typically referred to as a field force, which means it doesnt act by contact by at a distance. What most people would think of gravity as is the attraction between 2 objects. It is a very weak force compared to the other 3 which is why we only notice it when a mass is very large. The field also can only transmit the force at the speed of light. There is a particle which has been theorized, as is currently being looked for, called the graviton which would transfer the gravitational force. Its properties would be similar to the photon, such as it would have no mass. The way they are looking for this particle is by observing something called gravitational waves, which are ripples in spacetime caused by rapid motion of heavy masses, such as black holes. If gravitational waves are observed it would show that gravity is restricted by the speed of light and that gravitons are a major possibility.

In the last 3 posts i have talked about some particles of various types, but these were very limited descriptions, and even limited number of particles. There are many types of particles in our universe which are very intriguing and I hope to talk about more in the future.

Particles of Life - Part 2

This past weekend, at least for up here in Canada, it was thanksgiving. University kids all went home, who could at least, and were able to see family and friends they've been away from for the past few weeks and gave thanks for the life around them. That life, as we discussed in the last post, is made up of particles. Particles are everywhere, in all kinds of different forms of matter and energy. So far we've talked about some of the basic ones of matter. Now we will talk about some of those of energy.

The particle energy which we appear to interact with most would be the photon, which is the particle that makes up light or electromagnetic radiation. This is everything from x rays when you go to the doctors office to the microwaves that heat your food, to the gamma rays coming out of exploding stars. Light is everywhere. A photon is theoretically one unit, or division of light; one single particle. The different types of light, only one of which is the different light we see every day, come from the different energies contained in the individual photons. For example gamma rays are a type of electromagnetic radiation which contain a large amount of energy, and as a result we cannot see them. The interesting thing about light and electromagnetic radiation is it is not only represented as a photon or a particle, it is also represented as a wave, but this is something for another day.

Another intriguing particle of energy is the neutrino. Neutrinos are very tiny, weakly interacting but very abundant particles which are the result of some nuclear decay and interactions. They can also come from interactions in stars and other cosmic activity, so neutrinos are coming from everywhere in the sky. When I say weakly interacting, I mean very weakly. They have no electric charge so they are not effected by any electromagnetic forces, and they have a very very small mass so the influence of gravity is very small. They interact so weakly, they can pass through most matter totally unimpeded. There are trillions of neutrinos passing right through the earth, and even through your own body, with no affect at all.

This makes detecting neutrinos quite the problem. One way to do this is by using heavy water, or something called deuterium oxide. When the cosmic neutrinos pass through the heavy water, they can actually interact with the molecules and release a certain type of radiation that can be identified as coming from a neutrino interaction. This field of study is relatively new, but as scientist refine the methods of detection, we will be able to learn more about what neutrinos are.

These are 2 of the more common types of energy particles you will hear about in physics, but there are of course many more. There is another grouping of particles we have yet to discuss, and those are particles of force. We will discuss these in the next post.