I have always heard about dark matter, but I do not know what it means, what its uses are, and does it really exist?
In: Chemistry
“Dark Matter” is a kind of misleading name because it doesn’t describe a substance that we have directly observed and described. Rather, it’s a name that describes some cosmological observations that we have made. There are several different theories of dark matter, but the most popular one is that it’s just a type of matter that we can’t see, hence the name
To go into more detail the dynamics of observable galaxies suggest that they have more mass in them than could exist in all the stars that we can see. If gravity works the way we think it works, and it works the same way in all galaxies, and most of the mass in galaxies is in stars and black holes and other stuff we can observe, then something doesn’t add up. You might say well then, maybe gravity just doesn’t work the way we thought it does – that is a theory of dark matter called ‘mond’ for ‘modified Newtonian dynamics.’ The biggest problem with that theory though is that different galaxies appear to have different amounts of missing mass, which doesn’t really work with the mond idea. A more popular theory is called ‘CDM’ – cold dark matter – which just basically says dark matter is a kind of exotic particle that doesn’t interact with electromagnetism, so we can’t see it, but does interact with gravity, so it has mass, and generally moves around slowly (i.e., it’s cold).
As for uses of dark matter, well, we don’t know. But I would guess that we aren’t likely to find any any time soon. If the theory that dark matter doesn’t interact with electromagnetism is correct, then dark matter is not only dark, it can never form any molecules or compounds. Not only that, but it wouldn’t collide with normal matter in the expected way, because that mostly happens via electromagnetism. You could be surrounded by dark matter right now and be none the wiser; it would just be completely inert and invisible as far as we’re concerned
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