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> From a totally naive point of view it seems like whether matter is a solid, liquid or gas largely has to do with how those atoms behave as a group.

That's correct, phases of matter are properties of large groups of atoms.

Your example of a uranium atom suspended in other matter might not be the best to make this point, because mixtures of different substances can make things more complicated. For example, pure sugar at room temperature is a solid. Add it to a cup of water, and it's a liquid solution. Add much, much more sugar and you get phase separation with some solid and some sirup-y liquid.

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> And optical telescopes require astroids to pass in front of a light source ie sun

No they do not. Asteroids close to the Sun (as seen from Earth) are the worst possible observation condition. They are much easier to see if they are farther away from the Sun and we can measure their reflected sunlight at night (at the telescope site).

Your primary misunderstanding is that the Big Bang similar to an explosion originating from a single point.

The universe is likely infinite. The observable universe is a sphere with us in the middle. The edge of the sphere is where we see the oldest parts of the universe because the light from these distant places is just now reaching us, showing us what things looked like back then.

This sphere is getting bigger for an obvious reason, more and more light from distant places is reaching us. However, the sphere is also getting bigger because the entire universe (not just the observable universe sphere) is expanding.

Careful here not to imagine the entire universe’s expansion as a sphere, but rather every galaxy that isn’t locally bound to another galaxy by gravity is moving away from one another.

An oversimplified way to imagine this is to visualize an infinite 3D space with tennis balls each 10 meters from one another in every direction. Move forward through time and as the universe expands they are now 20 meters away from one another. Move back in time and they are 5 meters away from one another and so on.

Advanced telescopes and radars detect and track celestial bodies and determine their trajectory. We pretty much perfectly mapped the gravitational effects of all the large bodies in our solar system so a computer calculates future trajectory with the data observatories gather. Calculations are relatively simple even a phone app can do it with right data inputs.

But problem is the ones we cant see. Radar is useful in close range. And optical telescopes require astroids to pass in front of a light source ie sun

Bar = unit of pressure. Isobar = same pressure everywhere. Baryon does not have the same roots. It is then Isobaryon but when talking nuclear physics you can shorten it because you usually don't talk about pressure so Isobar.

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In very rough terms, it's like being able to catch a ball - you watch it to see where it's going to go, and then put your hand there.

With a comet, measurements of its movement are taken, they plot out the path it takes, they determine how the gravitational effect of the Sun and planets will affect it, and then see if the estimated path intersects with where the Earth will be.

Yes, it's a bit complicated (computers help), and there are always things that can mess up the predictions, but that's the overview.

As a first approximation, it's just Newtonian physics: The force between two objects with mass M and m at distance r is F = GMm/r^(2) where G is the gravitational constant. If you calculate the acceleration of the object in the field of a different mass, then the mass of the object cancels: a = F/m = GM/r^(2). That means we don't need to know the comet mass (which can be difficult to estimate) to find its acceleration. Measure its position a few times to find its location and velocity and you can calculate its future trajectory step by step. If only the Sun's gravity is relevant then the comet will fly in an ellipse and you can use Kepler's laws. See if the trajectory intersects Earth's orbit, and see if both objects will be in the same place at the same time.

To refine the orbit estimates, you want to look at non-gravitational effects: Is the object ejecting gas because the Sun heats it up? Is there significant radiation pressure? Anything else? You can also use some corrections from relativistic effects compared to Newtonian physics. All that goes into better estimates how the object will accelerate, so it will improve future position estimates.

Almost everything moves slowly compared to the speed of light. Typical velocities in galaxies are under 0.1% the speed of light, so things only move something like 100 light years or less over 100,000 years. That's not going to make a big difference if you look at something as large as a galaxy.

For relativistic jets from black holes it's an important effect and we need to take it into account.

The shape of distant galaxies depends on how their light is affected by gravity and space-time as it travels to us. One phenomenon that can distort the appearance of galaxies is called gravitational lensing, which occurs when a massive object bends the light from a more distant source, creating arcs or rings around it. Another factor that can affect the shape of galaxies is their relative motion to us. For example, the Andromeda Galaxy, which is about 2.5 million light-years away and 110,000 light-years in diameter , is moving towards us at about 300 km/s . This means that the light we see from different parts of Andromeda has left at slightly different times, but this effect is negligible compared to its size and distance. The Andromeda Galaxy appears as a nearly circular disk with two spiral arms , although its shape is also influenced by its interactions with two smaller companion galaxies, M32 and M110 .

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>Plasma seems intuitive because you are stripping pieces of the atom away, but what about the three basic phases?

Whether a simple material is a solid, liquid, or gas at equilibrium depends on which phase has the lowest Gibbs free energy at that temperature, pressure, and other conditions.

Nature prefers both strong bonding and high entropy, and the Gibbs free energy incorporates both as a tradeoff: It's the enthalpy minus the temperature multiplied by the entropy. This is why the higher-entropy phase always wins at higher temperatures: solid to liquid to gas. Visualization.

Thermodynamic entropy in this context is an ensemble property that isn't well defined for a single atom, so it doesn't make sense to talk about a single atom having a certain equilibrium phase.

No because you can only see the light hitting your eyes now. not the light into the future or past. Its only if you leave a open camera and record so that as the earth moves the stars leave lines of where we were in position to where we see them.

They are distorted. Its just a very minor effect. Take your Andromeda numbers, the 110000 difference would be between the front and back, but that wouldn't be a visible distortion because it would be along the axis of vision. if you look at the difference in time between the center and the edges, you get something like sqr( 55000 ) + sqr( 2000000 ) = 4,003,025,000,000, √( 4003025000000 ) ÷ 2000000 =1.00037805353776129308527162 so the light on the edge would be .03% older.

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There are animals that have no centralized brain, like a jellyfish or a sea anemone. So without a brain at all (but still with some neurons) they would by definition fit your criteria.

But “has no brain” feels like kind of a cop out. I think your best bet for an organism with a true brain might be a cephalopod. They have big brains, but also extremely complex and highly enervated arms.