Two pieces of big planetary news today, by @DavidOAtkins

The planet, which has been designated “PH1” in honor of it being the first such extrasolar planet spotted through the Planet Hunters website, is a burning hot gas giant slightly larger than Neptune, about six times the radius of Earth and located some 3,200 light years from our home planet.

Most remarkably, PH1 not only orbits two stars in what’s known as a circumbinary system, but those two stars are themselves orbited by two other stars located far away, some 900 times the distance from the Earth to the Sun, according to NASA.

Although PH1 is not located in its the habitable zone — a distance relative to its stars where liquid water could form on the planet — the view from the planet would include a fascinating four-star sky.

“All four would be visible,” wrote Chris Lintott, an astrophysicist at Oxford University and an author on a scientific paper describing the find, in an email to TPM. “The two more distant ones might each be as bright as the Moon was on Earth.”

PH1 was spotted first by two users of the Planet Hunters website combing through the mounds of data captured by NASA’s Kepler spacecraft, a photometer, or light meter telescope, launched into orbit above Earth in March 2009, specifically designed to hunt for Earthlike, habitable planets around other stars based on “light curves,” brightness measurements from those stars that may dip if a foreign object, such as a planet, crosses in front of them.

However, the Kepler mission produces an enormous volume of data, capturing brightness of 150,000 new stars every 30 minutes, on Kepler’s quest to survey the region of the Milky Way Galaxy around Earth.

Planet Hunters, an offshoot of the citizen science website Zooniverse, believes that human volunteers may be better equipped to sort through the numerous “light curves” than computer algorithms, “because of the outstanding pattern recognition of the human brain."

PH1 is the first planet to be found in a system with four stars, a gravitational environment that until now was thought to be far too intense for planet formation to occur.

“We think that planets form from a disk of leftover material around young stars, but we would have expected that disk to be disrupted by the presence of the other stars,” Lintott told TPM. “We will need to go back to the models and see if we can explain what’s happened, because right now it doesn’t make a huge amount of sense.”

The hunt for planets like our own has come up with a striking discovery: There’s a planet about the same size as Earth in the nearby Alpha Centauri system, and it's the closest planet found outside our solar system.

“Close,” of course, is a relative term. No one’s getting there anytime soon: The newly found planet, which orbits a star called Alpha Centauri B, is about 4 light-years, or 23.5 trillion miles, away.

Based on its mass, the planet is a rocky world and not gaseous, said Xavier Dumusque of the Geneva Observatory in Switzerland. He and his colleagues published the findings in the journal Nature.

t’s located extremely close to its parent star – Earth has a 365-day orbit around our sun, and this other planet orbits its star in only three days. Temperatures on the surface could be in the area of 1300 degrees Fahrenheit, scientists estimate. Rather than solid, the surface is likely to be lava.

But there is hope for life in that neighborhood: Small-mass planets like the one orbiting Alpha Centauri B are usually not alone with their sun, Dumusque said. Often there are other planets in the system, farther away from the parent star.

The next step would be to continue monitoring the shifts in light from the star, looking for other planets. Time is of the essence, however: As Alpha Centauri B and another star, Alpha Centauri A, move closer to each other, finding any planets in the area will become more difficult. Proxima Centauri, the closest star to Earth, may be related to this binary system.