Astrobiologists at NASA say that they now have a pretty good idea of what extraterrestrial plants may look like if we ever find them in planets outside our own star system.

Depending on what kind of star and atmosphere these planets may have, the plants could appear red, green or yellow. In the process, the team of researchers even uncovered a secret that leads to an understanding why plants are green in our planet.

It's common knowledge that the "white" light we see is actually primarily made of seven colors - red, orange, yellow, green, blue, indigo and violet. Botanists knew for years that our plants absorb blue and red light, and it baffled them to think why green shows up on leaves.

The NASA team explains that red and blue light are the most abundant and the most easily absorbed colors. Plants trap in the light to create food. As they do that, they are filled to capacity and do not require additional light. The green light is rejected and it bounces off, thus giving us the color.

In other planets, other colors may be more abundant on the surface. Depending on the star's age, the color varies. Alien vegetation may absorb and reflect different colors and that should give them a different hue.