Hello Everyone.

I'm writing a sci-fi story that has a solar system with three planets. The first is just a little to hot, the second is just a little to cold and the third is just right.

On the "just right" planet, I wondering if the other two planets can be seen at night from the ground? I envision them chasing each other across the heavens each night.

Would their orbits (one further, one closer to the sun) allow this? I figure the one farther away would have to be bigger and brighter (light a gas giant) to see both at once.

Any thoughts you might have would be appreciated. I'm not fussy about the size of the planets or type of star. If the physics can match the poetry I'll be happy.

Thanks in advance for all your help.

PGR

This is analogous to seeing the planets Venus and Mercury from Earth at the same time, which is not uncommon. But they don't exactly "chase each other" around the sky. Because Venus's orbit is closer to the sun then Earth's, from our vantage point Venus never gets very far away from the sun - only about 30 degrees. That's why Venus always appears to us as either a morning "star" or evening "star" - close to the horizon either shortly before dawn or shortly after sunset. Mars on the other hand can appear high in the sky at any time. It's brightest when at opposition from the sun, meaning when it is at its highest in the sky around midnight. There are times of the year when its apparent position may be close to Venus, and during those times you might say that the two planets appear to "chase" each other, but for the majority of time they are not terribly close to each other. Hope this helps.

Planets do appear more like stars than planets, because they are so far away and orbit the sun as our earth does, but moons are very different, because they are closer, and orbit the planet as the planet orbits the sun. Imagine how our moon looks, and then how the sky would look if we had more than just the one.

Ancient man discovered our fellow planets by noticing stars that changed position while others were fixed in the sky to the naked eye before telescopes. They made up all kinds of stories and myths about the sky as they named them and gave them human qualities. We use data collected now to understand better what we have been observing since man could see.

That doesn't stop the imagination from growing around such spectacular scenic wonder.