Space, the dark thing we see at night in the sky, with the floating light bulbs. We barely give any attention to it, even though it can easily be the most interesting, real life sci-fi thing out there; plus, we live in an era where we’ve learned so much of it, Newton and Galileo would be very jealous. For this opening article, I will start off by providing some cool space facts that should blow your mind, seriously, if you’re not amazed by what I’m about to say, you should get checked up for lameness.
Fact #1: We are made of star stuff:
You’ve possibly heard that one before, it is very simple really, all you need is hydrogen and gravity. First you have to understand how a star works: hydrogen is the most abundant element in the universe, given that it’s the lightest and most easily formed; there are clouds of hydrogen gas rambling across the universe, these can be thousands of light years (unit of distance which I will explain later on) in diameter. Throughout millions of years, these clouds get denser and denser, this density contributes to an increase in gravity force, which in turn makes them even denser, to the point that they compress so much that BOOM, baby star Sunny is born.
The compressed hydrogen particles located in the core of baby Sunny start to collide against one another due to intense pressures and temperatures, these collisions cause them to merge and form helium, a slightly heavier element; this collision causes a liberation of energy in the form of photons (light), when we add all these collisions together we can understand why a star emits such an abundance of light, this exothermic process(releases energy) is called nuclear fusion, because the hydrogen atoms fuse with one another. This energy causes an outward pressure from the core, so why don’t stars expand indefinitely until its energy is exhausted? We have gravity to thank for that, the massive gravity present in a star causes an inward pressure, just as you’re pulled to the center of the earth by its gravity (actually you’re following a path in the space-time continuum but let’s not get into that), the elements located at the surface of a star are pulled in by its gravity. Hence, the two forces (outward from the nucleus and inward from the surface) cancel each other, forming a state of equilibrium that allows the star to live for millions of years.
As more helium is formed, now we have it along with hydrogen colliding against one another forming heavier and heavier elements, until we reach iron, iron is the last element that is produced at a stars’ core. Then the following happens, as explained by astronomer Robert Kirshner: “Once a star has built an iron core, there is no way it can generate energy by fusion. The star, radiating energy at a prodigious rate, becomes like a teenager with a credit card. Using resources much faster than can be replenished, it is perched on the edge of disaster.” Although I will say I disagree with him most fundamentally in his stereotype of a teenager, because many adults cannot be trusted a credit card either.
After the iron core is formed, nuclear collisions cease, and said nuclear energy that was “pushing out” from the core is no longer there, hence the surface that was previously pushing inwards thanks to gravity has nothing to keep it at bay, which makes the star collapse onto itself. When this happens, the star is now compressed so tightly that it becomes as dense as an atomic nucleus (I mean it’s like very dense), when it cannot be compressed anymore it explodes with an energy equivalent to 1027 atomic bombs, this intense heat and pressure acts as a catalyzer for new nuclear reactions that weren’t possible at the core, forming most of the elements that follow iron in the periodic table. This explosion is called a Supernovae; after it, depending on the size of the star before the explosion, either a black hole or a neutron star will form. A neutron star is an ultra-dense star, but not enough to trap light, the main requirement to be promoted to the super fancy black hole status.
Now we see that at some point, billions of years ago, a star exploded and formed all the elements that make us. “The nitrogen in our DNA, the calcium in our teeth, the iron in our blood, the carbon in our apple pies were made in the interiors of collapsing stars. We are made of star stuff.” –Carl Sagan
Fact Número Dos: The Elements that we know represent only 5% of our universe:
Yeah, that whole process I just explained to portray the beauty of outer-space, only accounts for 5% of everything, so what is the other 95%? Dark matter and dark energy, duh. We are getting into some deep stuff, so get your neurons to forget about that like you accidentally gave your crush’s two-year-old pic, and buckle up.
Dark matter accounts for ~27% of the universe, at least that is what we think, we’ve never actually proved dark matter exists. We have theorized it exists because of the following: Astronomers were observing that galaxies were spinning much faster than they should have given their mass, especially the rotation speed in their outer-rims; they were spinning as if they had much more mass than the calculated value. This didn’t made sense, it is like if a country with no history whatsoever in soccer, bad climate, no stadiums and a lot of money were elected as a host nation for a FIFA World Cup, there must have been something sketchy going on in the background (I’m not talking about Qatar you are). The questions to this answer became a holy grail in the physics world. Through simulations they reached a conclusion: there is an invisible matter that is very massive (hence exerts high gravity force) present within galaxies, numerous experiments have been done to try to detect it, but nothing definite so far, however, it is the best explanation we currently have. So we have that 5% of the totality of the universe, is represented by our “normal” elements; 27% dark matter; and the 68% remaining is dark energy, which seems came from Stan Lee’s mind.
Dark energy was theorized because of the same reason than dark matter, something didn’t add up; hence again we simulated until we reached a conclusion. We have the facts: in the dark matter scenario a rapidly spinning galaxy was the fact; then we try to match our theoretical equations to these, if our equations don’t match them, we must change our parameters. With dark energy, the fact is that the universe is expanding, accelerating its growth. With our primary calculations of the mass of the universe, this shouldn’t be possible, the universe should be slowing down because that is the tendency of gravity, to contract; just like baby Sunny when he grew up.
Dark energy hence rose as the primary hypothesis for the expansion of the universe, all we know of it is that it causes the expansion of the universe. The theories surrounding dark energy are fairly complicated, because of which I will not try to explain them, not because I don’t understand them (actually yeah it’s because I don’t understand them).
Fact #Tres: There is probably a supermassive black hole at the heart of every galaxy:
Black holes are, by definition, points where gravity is extreme enough that nothing can escape their orbit, not even light. However, the size of a black hole can vary wildly; in theory there could be black holes as small as an atom, this of course wouldn’t have the same gravitational pull as a black hole the size of Earth, and neither of these would compare to the effect of a supermassive black hole.
The gravity force exerted by a black hole is measured in solar masses, although they are massless, they are warps in the fabrics of space-time. A black hole with one solar mass would have the same gravitational effect on its surroundings as our sun has in the solar system. The main difference would be that the black hole would be much smaller, hence denser. Supermassive black holes start at some hundred thousand solar masses, and can reach up to 66 Billion solar masses, like the black hole named TON 618 does; 66 Billion, that is 66 followed by 9 zeros, sixty-six, billions, with a B. These ginormous entities in recent years been proven through simulations to inhabit the center of most galaxies. Just as Earth and the rest of planets orbit the sun in our solar system, the solar system orbits a supermassive black hole at the center of the Milky Way. We used to think that the center of galaxies were merely a place where a high population of stars made it extremely dense, hence keeping galaxies together, but it makes it so much cooler that there is literally a giant light-eating hole there around 26,000 light years away from us, just chilling, probably eating some stars right now. And by the way, that was billions, with a b.