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What is the universe made of?
What we think we know about the universe has been tested a lot in the past few decades: The answer used to be “matter,” but now we know that the universe is full of materials and energies that we have no clue about. It’s both a terrifying and amazing time to be alive.
If you’ve ever asked the question “What is everything made of?” we hope to illustrate the answer on a grand scale. Check out our graph of the composition of the universe as reported by leading scientists.
What is the most abundant element in the universe?
Out of all the known matter there is, the most common element in the universe by far is hydrogen, representing 75% of all known matter. With one proton and one electron, hydrogen is first on the periodic table. It’s the simplest element in the universe. Number two on the periodic table, helium, represents about 23% of the matter in the universe. That means the last 2% of matter is literally everything else you know!
The reason for this, sometimes referred to as “big bang nucleosynthesis,” is because these were the first elements that could have been created after the big bang reaction. It took a lot of time for quarks and energy to cool down and slow down, but when they did, hydrogen gas was the first of the elements to form. Put simply, hydrogen being super-abundant is a consistent fact with what we know about the universe so far.
However, if you are asking, “What is the most common stuff in the universe?” the answer is not hydrogen — not by a long shot. The most abundant stuff in the universe is not matter at all, since matter only makes up 5% of the known universe, but dark energy, which makes up 68% of the universe, and dark matter, which makes up 27%.
What is dark matter?
Dark matter is stuff that has all of the normal gravitational hallmarks of matter but is not visible to us by normal means.
Don’t be alarmed by the word “dark.” Why do we call dark matter “dark”? It’s simply because we can’t “see” it, either with the visible light spectrum or other methods currently at our disposal. According to NASA, dark matter is not dark clouds of normal matter (or baryonic clouds), antimatter (which would reveal gamma rays), or black holes (as we’d be able to see gravitational lenses as the black holes encounter light). So what is this stuff?
We’re not sure, but the prevailing theory has been that dark matter is made up of WIMPs, or weakly interacting massive particles. Studies so far have not led to much evidence of WIMPs, however.
So the universe is made partly of some material that’s similar to matter and exists on a huge scale, but that’s only 27% of the universe. What makes up the other 68%?
What is dark energy?
Dark energy is energy that believed to be causing the universe to expand at an increasing rate. Like with dark matter, the “dark” implies that we can’t see it, though we know it must be there. How do we know it’s there? It’s pretty complicated, but in simple terms, we’ve been able to observe distances between objects and see how space expands at a fast pace, which it wouldn’t be able to do without some sort of energy out there pushing them apart. We know that dark energy exists as a result of two separate teams in Hawaii reaching the same conclusion after a massive set of studies watching the movement of Type 1a supernovae in 1998. Since then, more and more evidence has piled up for the so-called “runaway universe.”
In a nutshell, the universe’s expansion is not slowing down after the big bang, as one would assume, but speeding up at a faster and faster rate, and we don’t know why. It’s one of those things where the more we study it, the more interesting and mysterious it gets.
People assume that because both dark energy and dark matter have the word “dark” in the name, they must be related. That isn’t necessarily the case. They don’t appear to be related in any way, as of now. There are big differences between dark matter vs. dark energy: Dark matter behaves like unseen matter, pulling on galaxies and affecting certain areas of the sky that we can see, and dark energy is a force pushing matter apart.
It’s pretty incredible that we don’t really understand what makes up 95% of the universe!
What is matter in science?
Those who were told as children “everything is made of matter” may be upset to find out that matter only makes up 5% of the universe. Matter is defined as substances that take up space and have mass. All matter is composed of quarks and leptons (the stuff that makes up atoms). Everything we know in our day-to-day lives as human beings, from a keyboard to your phone to the air we breathe, is made up of matter. Matter can be a gas, solid, liquid, or even plasma and is made of atoms. It makes up our star, the sun, our planet, Earth, and our galaxy.
What are common elements?
Besides hydrogen and helium, the most common elements are oxygen and carbon. That means H, He, O, and C are the four most common elements out of all matter. Beyond that, the abundance of elements drops off sharply, as our matter chart shows.
We get heavier elements when bigger stars explode, merge into other stars, or die. Heavier elements on the periodic table tend to be pretty rare. For example, gold is only created when neutron stars merge, so we’re pretty lucky to have enough on our planet to make rings out of it!
Using extremely advanced techniques to study our solar system, scientists have found the abundance of elements of the universe. Seeing just how rare our stuff is in the grand scheme of things can really help us understand the scope of the universe as well as just how much we don’t understand yet!