Of course. They all see the Sun. At any time, obviously half the planet is facing the Sun and the other half isn't. And they all spin, so there will be day when you can see the Sun, and night when you can't see the Sun. They spin at different speeds, so how long a day is varies a lot.
On that subject,...
Best answer: Of course. They all see the Sun. At any time, obviously half the planet is facing the Sun and the other half isn't. And they all spin, so there will be day when you can see the Sun, and night when you can't see the Sun. They spin at different speeds, so how long a day is varies a lot.
On that subject, Venus spins "the wrong way" (the opposite way from the direction it orbits the Sun) and slowly, so slowly that it takes more than a Venus year to spin once. In that sense, a day on Venus is longer than a year! But because it's spinning "backwards", an actual day from sunrise to sunrise lasts a bit over half a year. Though whether you'd actually notice is another question - Venus is covered in thick acid clouds that would make it impossible to see anything in the sky (astronomers have only been able to map it by radar), and they also hold in heat so well that it doesn't cool down at night. As the Russians found when they sent probes to land on Venus, basically you have to build your probe like a tank so it won't melt, get eaten by acid, or get crushed by the huge atmospheric pressure.
There are some more oddities. Earth has an atmosphere (fortunately not like Venus), and its axis of spin isn't far off vertical compared with the direction it travels in orbit round the Sun. Not all other planets are like that.
If a planet has no atmosphere, then there will be a black sky during the day as well because there is no air to scatter the sunlight. Mercury is like this.
If the axis of spin is very far off the vertical, days are going to get weird. Uranus is virtually "lying on its side" as it goes round the Sun, so how long a day is varies enormously depending on where on the planet you are - if "on it" actually means anything, as nobody knows if it has any solid surface. At the poles, a full day and night are the same length as a year (84 of our years because it's so far off). Which is true on the Earth as well - the scientists at the South Pole base get a 6 month day followed by a 6 month night. But at other places on Uranus there will be some wild variation on how long a day or night is.
And with the gas giant planets, they're so far away from the Sun that it won't be significantly brighter during the day, or significantly warmer.
4 days ago