Life In The Universe

Two recent studies seem to be good news for those arguing that life is common in the universe. In one, the Hubble Space Telescope was used to image Kuiper Belt objects, those objects that orbit with Pluto and beyond. Hubble showed a range of colors, with those objects that orbit in the plane of the planets having a distinctly reddish hue. Astronomers interpret the colors as indications of organic molecules. Not life, but the building blocks of life, and they say that implies those building blocks are common throughout the universe.

The other study looks at how common worlds similar to Earth might be by monitoring nearby G- and K-type stars, looking for wobbles in the stars that might be caused by planets' gravitational tug. The Sun is a G-type star, for example, and K-types are slightly smaller. The study concludes that worlds the size of Earth are probably fairly common around stars similar to the Sun. Perhaps a quarter of such stars, the study suggests, may have at least one Earth-like world in its gravitational sway.

Taken together, the two studies do not cinch the case for life in the universe. However, if the chemical building blocks of life are common features of solar systems, and if Earths are relatively common around Sun-like stars, an Earth orbiting at the right distance from its star could be occasionally showered with organic molecules. One, or more, of those showers could lead to life.