Some stars make more nuclear fusion, or just have more energy.
that's because some stars are closer to the earth; another reason is that some stars get more sunlight than others; another reason IS that the star might not have that much enregy
Because some are larger than others and some are closer than others.
'Appear' would become 'appeared' in the past tense so the sentence would simply be 'some stars appeared to be brighter than others'.
Some are closer than others and some have more power and brightness.
not all stars are the same temperature and the temperature matters, it also effects how bright a star is. (i am not 100% sure about this answer but that is all i know)
that's because some stars are closer to the earth; another reason is that some stars get more sunlight than others; another reason IS that the star might not have that much enregy
Because some are larger than others and some are closer than others.
'Appear' would become 'appeared' in the past tense so the sentence would simply be 'some stars appeared to be brighter than others'.
How big, how hot (color/amount of energy emitted), how far, light pollution at viewing site
Some are closer than others and some have more power and brightness.
No it is not. It is less bright than some, but brighter than others.
The Sun is bigger than some stars and smaller than others. It is brighter than some stars and dimmer than others. Relative to the Earth it is much closer than all other stars.
Because they are closer or actually brighter.
not all stars are the same temperature and the temperature matters, it also effects how bright a star is. (i am not 100% sure about this answer but that is all i know)
because the sizes and the distances away from earth are different
It is better to say that the sun appears brighter because it is closer. Some stars are actually brighter than the sun.
"Luminous" in this context means "bright" - how much light (or how much energy in general) does the star emit. Note that stars look dim to us only because they are far away - some of them are actually several times brighter than our Sun, in absolute terms. That is, if you would see several stars, and our Sun, at a same standard distance, some stars would be dimmer, but others would be brighter, than our Sun.