Wikipedia : "a mineral or mineral species is, broadly speaking, a solid chemical compound with a fairly well-defined chemical composition and a specific crystal structure that occurs naturally in pure form".

So artificial solids (plastic, steel...), or solids coming from living organisms (wood, coal), are - most of the time - not minerals. And rocks are generally a bunch of different minerals stuck together.

Gravity depends on the mass of the planet, but also on your distance to the center of the planet. If you're on the ground, that means it depends on the planet's radius. What you say would only work if the planet was the same size as the Earth, which is generally not the case.

Everything attracts everything with gravity, so in theory you would have to calculate the gravity pull from every planet, star, moon, everything. But generally, most of these objects are too far away to really have a significant effect. If you're on the surface of a planet for example, gravity of other planets and moons are completely negligible. We are attracted by the Moon when we're on Earth, but the gravity pull of the Moon is approximately 0.0006% that of the Earth.

But in space, if you're somewhere between Earth and Moon, you'll be attracted by both of them and you'll have to calculate both values to know towards which direction you'll be attracted.

Jupiter is mainly composed of hydrogen and helium, all the other gases are in trace amounts. It is those gases in trace amounts that give the different colors.

Helium and heavier gases are indeed pulled closer to the center of the planet, because of gravity. But they nonetheless form a sphere, because that's the shape that minimizes the gravity pull.

There is still helium on the outer layers of Jupiter though, because helium is a gas. That means that helium atoms are moving around really fast and have a lot of kinetic energy, so even if gravity pulls them towards the center of the planet, some atoms still manage to stay in the outer layers. And contrary to some liquids that you cannot mix together (oil and water), gases mix together very well. The same is true for other gases. Solids, on the other hand, have fallen towards the center of the planet, so we cannot observe them, even though we still think there must be some rock and ice at the very core of Jupiter.

Yes it is, too ! What you said in your message was perfectly true. The further we look, the further back we are looking in time, and we cannot see further and older than around 380'000 years after the Big Bang because the Universe was opaque before that. So an object that formed and emitted its first light some millions of years after the Big Bang, but whose light has to travel more than 13.8 billion light years (the Universe is 13.8 billion years old), is not visible by any telescope.

An atom is composed of a nucleus, containing protons and neutrons, around which there are electrons. The number of protons determines what element this atom is (one proton, it's hydrogen, 6 protons it's carbon, 92 protons it's uranium...)

Plasma is a state of matter, like gas, liquid and solid. It is composed of elements. Plasma is matter that is so hot that the electrons are not bounded to atoms anymore and start moving around. But the atoms are still there, they've just become ions (atoms which have lost electrons). For example, the Sun is made up of a plasma of mainly hydrogen and helium, with some other trace elements.

The vast majority of observable matter in the universe is in the stars. The Sun makes up 99.85 % of the mass in our Solar System. So yes, the observable matter is nearly all in a plasma state, and is mainly composed of hydrogen and helium.

Now you may start to wonder why I talk about "observable matter". Well, because there may actually exist another type of matter, called dark matter, that has been hypothesized to explain why galaxies are heavier than they seem to be. This dark matter may be more than 5 times more abundant in the Universe than common matter, but we haven't observed it yet.

In the observable Universe, there are also things that are not elements.

First, elementary particles : electrons, protons or neutrons not in an atom, photons (particles of light) and other more exotic particles like muons or neutrinos. These are things smaller than atoms. Particles don't stick together to form bigger things like atoms do (except protons, neutrons and electrons that make up atoms), so you can't have something visible made of muons.

Second, matter that have been crushed so much that in the atoms, electrons and protons have fused together to make up neutrons. This requires an enormous gravity and is only happening in really massive stars when they die : they form what is called a neutron star.

And finally, black holes. Matter crushed so much by gravity than it's not even matter anymore. It's just a point with an enormous mass.

After the Big Bang, the matter was so dense that any light that was emitted was instantly reabsorbed by the surrounding matter. So we cannot see light from that time. It's only when Universe had expanded enough that some photons were able to travel without being disturbed. These photons were emitted approximately 380'000 years after the Big Bang, and they constitute what is called the "cosmic microwave background". You cannot see further than that (with light).

But still, that's very far, and the first galaxies are no more than a few pixels in our better telescopes. So building better telescopes does help us finding further and further objects (the JWST for example, has already found a galaxy further than all the ones previously known, dating from around 300 million years after the Big Bang).