Of course, to even attempt to answer the question you have to clarify what is being asked. We can answer how big the observable universe is, for instance.
"The universe (Latin: universus) is all of space and time and their contents, including planets, stars, galaxies, and all other forms of matter and energy."
In question 7. you're referring to "relativistic mass" as just "mass". It gives the quiz-taker the false idea that an objects mass changes with time, which it does not. "Relativistic mass" is an abstract concept taught to students to simplify the inherently confusing nature of relativity, but that's it, a mathematical concept abstracted from reality.
Highly suggest everyone watch these two videos on the topic:
or read the following paper:
I should really stop writing comments whilst sleep deprived...
However, there is no indication in the way the question is worded that this is referring to rest mass nor invariant mass.
If the observer measuring the mass of the object was in the same reference frame as the object, and thus not observing any change in mass, the observer would also ostensibly not be observing any change in the speed of the object. So, at least to me, the question is not misleading.
the universe makes no sense.
Remember E=mc^2 which absolutely applies here: as a mass approaches the speed of light, its energy increases, but this could be equivalently interpreted as an increase in mass, tending towards infinity.
Alternatively, as the object approaches the speed of light, the force required to accelerate it at a constant rate approaches infinity (because you need infinite energy to make a nonzero mass move at the speed of light). In this interpretation, because acceleration is constant and force approaches infinity, then by Newton’s 2nd, the object’s mass must be approaching infinity.
I think it’s important to remember that mass doesn’t work like we want to think it does, just like time or light.
It sure is weird though…
Two objects starting from the same spot can't move away from each other at faster than the speed of light.
But the space between objects can increase faster than the speed of light if space itself expands.
So the answer to #16 may be correct, but the reasoning why is either wrong or else I did not understand the explanation.
However, there are stars that are far enough away that the expansion of the universe means that light speed will not theoretically ever reach these stars because they space between is expanding faster than the speed of light.
So even with the most powerful computer that was able to account for every conceivable variable possible you wouldn't be able to predict the future to 100% accuracy
Apart from that, nice one!
If you are leaving finite / infinite as an unanswered question, it would be equally correct to say that the answer to "Can something have infinite density?" is "We don't know"
You mean because we have no way of telling wtf is at the center of a black hole right?
Maybe my relativity is a bit off, but I took a modern physics class and I'm pretty sure that 16 is wrong isn't it?
And there is another easy reason that we can't communicate with every star we see: some of them may already be destroyed since we are seeing the past.
1. Energy can only become matter if it becomes an equal amount of ordinary matter and antimatter, by the conservation of the lepton number and baryon number.
5. Singularities are theorised but have never been directly observed, since they can only appear inside a black hole.
9. Again, an equal amount of ordinary matter and antimatter have to emerge simultaneously.
12. Not all interpretations of quantum mechanics agree on this point, though I am not knowledgeable enough in this area to explain what they do agree on. I believe that when one particle changes, apparently "causing" the other to change, this is not the result of any controllable process and so no causation can be proven (only correlation).
14. This is only true if...
1 and 9 are kind of nitpicking as you can argue that ordinary matter and antimatter are both types of matter, and 5 could be explained by adding that it is a prediction of theoretical physics and not observed. 12 and 14 need more assumptions that not all physicists agree on in order to be correct.
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