Does It Really Antimatter?

There´s Pi all day

but I´m crying anyway

Picture: Artist's illustration of the surface of Proxima b, an Earth-sized, potentially habitable world that orbits the nearby M-dwarf star Proxima Centauri. | Credit: M. Kornmesser/ESO

Text by Sheyna Gifford | Astrobiology Magazine

It was a good week for astrobiology. Within days of NASA’s announcement that the necessary ingredients for life likely exist in the Saturn moon Enceladus' subsurface ocean, scientists gathered at Stanford University to discuss discovering life outside the solar system.

Noting how "the search for life in the universe has been transformed from speculation to a data-driven science," speakers like Stanford physicist Peter Michelson offered detailed plans for finding life on exoplanets.

Over the course of two days on April 20-21, dozens of scientists attending the Breakthrough Discuss conference contemplated options for exploring planets in other star systems. These options include using a new generation of powerful telescopes for long-distance observations, as well as advancing a first-of-its-kind technology to visit other star systems — all within the next generation. [10 Exoplanets That Could Host Alien Life]

What these strategies have in common is a focus on observing habitable-zone planets in our local stellar neighborhood. In this neighborhood alone, within 30 light-years or so of our solar system, astrobiologists have already identified several potentially Earth-like exoplanets and dozens of systems that may harbor Earth-like worlds.

These exoplanets, identified by the effects they have on their parent star, are rocky and roughly the same size and density as Earth. They orbit their stars at a distance that would allow liquid water to exist on the surface, given the right atmospheric conditions. There is, however, at least one major difference between our planet and these potentially-habitable exoplanets: They aren't circling stars like our sun.

The diagram shows how new technology developed at Caltech will help astronomers search for molecular bio-signatures on exoplanets. Coronagraphs block a star's light, making orbiting planets easier to see. High-resolution spectrometers would help further isolate a planet's light, and could reveal molecules in the planet's atmosphere. | Credit: Caltech/IPAC-TMT

On the spectrum of stars, our sun is what's known as a yellow dwarf. It's bright, and not terribly large compared to the largest stars in our galaxy. Yet, even middling stars like our sun aren't all that common. Our local stellar neighborhood — and probably the universe as a whole — is filled with many more low-mass stars. There are 20 yellow dwarf stars like our sun nearby and 250 M-dwarfs, a variety of star so small and dim that, despite their abundance, they can't be seen with the naked eye. Over the last three to four years, every single low-mass star we've studied appears to have at least one planet. Usually, they have more than one.

"How common are planets orbiting low-mass stars? Very common indeed," Courtney Dressing, an astronomer at the University of California, Berkeley, said during a presentation at the conference.