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A day is defined as the time it take a planet to revolve once on it's axis. So it is the time it takes for a planet to "spin" once.
A planets day (solar day) is the time it takes to rotate once on its axis relative to the sun, the synodic period. A year on a planet is the time taken for the planet travel once around the sun.
No, that's a `year`. A day is when the planet has spun once on its axis.
The Earth rotates on its axis in one day. Strictly speaking that's the "sidereal day" not the "solar day". Also, by definition, each planet rotates once in a period that's the "sidereal day" for that particular planet.
Roughly, the day. To be precise, the day also depends slightly on the planet's orbit around the Sun, but if the time it takes for a planet to rotate once is short, compared to the time of an orbit, it won't make much difference. For instance, a day on Earth is 24 hours; the time it takes Earth to rotate once is about 23 hours and 56 minutes.
It revolves around the sun once a year and rotates around its axis once a day.
5 billion tons
Day and night are caused by the rotation of the Earth on its axis. During the day, the side of the Earth facing the Sun experiences daylight, while the side facing away experiences night. As the Earth rotates, different parts of the planet are alternately exposed to sunlight and darkness, creating the cycle of day and night.
The planet Earth rotates on its axis exactly once per day.
Jupiter rotates on its axis every 10 hours.
once a day
The day is the period of a planet's rotation, or how long it takes to spin once on its axis. Day might also refer to the fraction of its rotational period when an observer can see the Sun, as opposed to night, when the sun is below the horizon.