#physics
So the word I picked for A was (somewhat predictably) Astronomy!I thought it would be a good idea just to define what it actually is and where it comes from
The definition of astronomy is the study of celestial objects: basically anything that we can see floating around in space. This includes everything from tiny dust particles floating around the spiral arms of galaxies, to superclusters of galaxies lining up along dark matter fringes, forming the largest structures in the known universe! So its a pretty big topic! (Photo from NASA APOD)
Astronomy involves looking at the physics, chemistry and even a bit of biology of these objects to try and explain what is happening. We can use both observations and theory, and one of the key problems in modern astronomy is trying to fit the two together, specifically with things like dark matter and quasars. We need to use a wide variety of wavelengths to study space, from gamma rays to radio waves, and each section of the electromagnetic spectrum enables us to learn something different.
It is one of the oldest sciences, humanity has been staring at the stars for 5000 years, but it wasn’t until the invention of the telescope that we started making real progress. The beauty of astronomy is that anyone can do it, you only need to look up at night, and amateurs have contributed a surprising amount to the field.
The word astronomy is interchangeable with astrophysics; they are both used, but mean the same thing. This is something that confused me when I first started learning about it!
Taking a break from Tumblr over the next 2 weeks as I struggle through my university exams! Wish me luck, I’m going to need it!!!!!
In the last post of my dark matter explained series, I talked about the theory that is most likely to be correct in explaining the weird rotation we see in galaxies. This is a yet undiscovered particle called a WIMP which could be anything from a heavy neutrino to a supersymmetric particle. Whatever it is, it has to fit onto the Standard Model somewhere.
But this isn’t the only theory. Astrophysicists have been working since the late 1930s on this topic, and there are other explanations around. Another possible one is the theory of MAssive Compact Halo Objects (MACHOs) which says that perhaps there are really big, dark objects; they could be interesting things like brown dwarfs or maybe black holes. They would work in the same way as clumps of dark matter: they would sit around the outside of galaxies, causing this part of the galaxy to rotate faster than the central part, and causing us to see these strange rotation curves.
They could also explain a phenomena called gravitational lensing which is sometimes attributed to dark matter.
This image shows a very massive object (in this case, a star) which is directly in front of a galaxy many light years behind it. The star has so much mass that it is able to bend the light around causing an “Einstein ring” to appear. It is called this due to Einstein’s theory of General Relativity, which explains this quite nicely.
This diagram shows what is happening, and how a MACHO could be used to explain the effect.
So what could a MACHO be? An isolated black hole would be a good example, because when they are far away from any other stars, than they cannot form an accretion disc, which would make it basically invisible to our eyes. The only way we can see them is through effects like gravitational lensing.
Even MACHO theory seems like a really good explanation it just doesn’t work well enough to explain rotation curves. It seems there just isn’t enough normal matter present in the Universe to account for MACHOs being present in nearly every galaxy. A new type of matter needs to exist to explain this, and unless there are massive stars or black holes made out of a new unknown particle then it seems like MACHOs just won’t work.
But what if everything we have worked out is wrong? What if galaxies don’t actually need more mass? What if Newton was wrong??
More to come in the next post!
Just realised how long my last post was! I’ll try and cut it down for the next one in my Dark Matter Explained series! Stay tuned :)
saturday 04/06/22
physics! i just wanna do a little rant on this subject because life played me. i used to hate math with a burning passion but i was always great at it. anyway i took physics because i kind of enjoyed it but i was apprehensive bc it was so heavily math based and i didn’t want that. anyway guess what? i can do physics for hours on end. its a subject i genuinely adore despite how hell bent it is on causing me suffering and failure. i fucking love it. and by extension, i’ve loved math. (yes that is a coffee stained data booklet.)
♫ hit em where it hurts - pawpaw rod ♫
friday 03/06/22
fuuuck i had three papers today. im wiped. history was ok, math violated the fuck outta me and chem was a game. now to revise for physics n english come monday
♫ glass house - pawpaw rod ♫
monday 30/05/22
i’ve finished most of my chem topics!! and i’ve done a lot of history and math! feeling semi prepared, because they’re all paper 1 they’re relatively easy so not much revision is needed. but i’m trying to finish all my revision for them so that i can channel energy into physics and french which are weaker subjects
♫ feels like - lucky daye ♫
This is cool (btw it’s originally from a YouTube channel called Brick Experiments)
Not quite sure whether to be concerned by the fact that I have Physics paper one on Thursday and I still cannot understand how Ships that weigh tons float on water.