麻豆传媒

麻豆传媒 — Planet-hunting telescopes have recently taken a huge leap in their ability to find 鈥渆xoplanets,鈥� or planets orbiting other stars. In just the past six months, astronomers have announced the discovery of more than 700 such worlds, bringing the total to more than 1,700. These discoveries include the first Earth-size planet found in what鈥檚 called the habitable zone of a star, where liquid water could exist; the oldest known planet that could support life; and an unusual giant planet that orbits its star at 2,000 times the distance between Earth and our sun.

Earlier this week, three planet hunters came together during a live Google Hangout to discuss the discovery boom, consider what state-of-the-art telescopes can 鈥� and can鈥檛 鈥� tell us about exoplanets, as well as ponder the likelihood of finding evidence of life on another planet.

鈥淲e鈥檙e in this era now where there are 1,700 planets known, and [for many of those planets] there鈥檚 really no analogy in our solar system,鈥� said Bruce Macintosh, a member of the Kavli Institute for Particle Astrophysics and Cosmology and the principal investigator for the Gemini Planet Imager. 鈥淲ith the exception of a few specialized individuals, we have no idea what the heck they鈥檙e made of. And so this enormous puzzle about how the universe has made systems so different from our own is extraordinarily exciting.鈥�

Even though even the closest exoplanets are distant objects, astrophysicists are able to measure many of their characteristics including size, mass and density. They can now also determine some of the chemical make-up of a planet鈥檚 atmosphere 鈥� and are able to detect more detail by the year.

That will help not only reveal the conditions on individual planets, but also answer big-picture questions like how planetary systems form and just how common the types of planets in our own solar system are. It should also move us closer to answering the biggest of the big questions: whether life exists elsewhere. Said Marie-Eve Naud, a University of Montreal PhD student who recently helped discover a new giant planet, 鈥淚鈥檓 not that confident, but I dream that we will have a hint of the answer by the time I leave this planet.鈥�

Zachory Berta-Thompson, the Torres Fellow for Exoplanetary Research at the MIT Kavli Institute for Astrophysics and Space Research, shares Naud鈥檚 cautious optimism that in the coming years there will be significant new insight toward answering this question. 鈥淚n the next decade, we are just barely at the edge of being able to detect molecular oxygen in a planet鈥檚 atmosphere,鈥� he said. 鈥淚f we find the right planet鈥攎eaning it鈥檚 the right size and the right temperature, and around one of the closest very small stars, so it鈥檚 very easy to observe鈥攖hen鈥� you just might be able to do it.鈥� While not proof of life, the observation of molecular oxygen would be a big step in that direction.

鈥淲hat is really fascinating at this stage of exoplanet science is that we have many methods, and all the methods can鈥� bring different information,鈥� said Naud. 鈥淲hen we are able to combine different methods, we are able to see so much more.鈥�

The complete discussion recorded live is available at