The first-quarter Moon is gliding across the constellation Gemini tonight. Gemini’s twin stars and the planet Mars form a bright arc above and to the upper left of the Moon at nightfall.

Mars is the brightest member of the arc. It’s roughly twice as bright as the star Pollux, which is twice as bright as Castor.

Pollux is just 34 light-years away. And it hosts a giant planet – one of our closest planetary neighbors. The planet isn’t likely to be inhabited, though – the star, the planet, and the system’s age all conspire against life.

The star is past the prime stage of life, so it’s puffed up to giant proportions. That bathes the planet in light, making it hot. The planet – known as Thestias – is about three times the mass of Jupiter, the giant of our own solar system. That means it’s a ball of gas, with no solid surface – probably not a good home for life. And the system is only a bit more than a billion years old, so there hasn’t been a lot of time for life to take hold.

On the other hand, if the planet has big moons, conditions there might be a bit more favorable for life. But those conditions won’t last long. Pollux will grow bigger and brighter in the future, making the moons even hotter. After that, the star will cast off its outer layers, blasting the planet and moons. Only the star’s hot, dead core will remain – zapping the surroundings with deadly radiation.

More about the Moon and Mars tomorrow.

Script by Damond Benningfield