Are Some Distant Planets a Mirage?

“It was thought that the reliability of the Kepler exoplanets detection was very good – between 10 and 20% of them were not planets. Our extensive spectroscopic survey, of the largest exoplanets discovered by Kepler, shows that this percentage is much higher, even above 50%. This has strong implications in our understanding of the exoplanet population in the Kepler field”.

-- Alexandre Santerne, Instituto de Astrofísica e Ciências do Espaço, discussing a new study by his team - SOPHIE velocimetry of Kepler transit candidates XVII. The physical properties of giant exoplanets within 400 days of period.  The team used SOPHIE (Spectrographe pour l’Observation des Phénomènes des Intérieurs stellaires et des Exoplanètes) to conduct its study, which is located in an observatory in france.

KIC 8462852: Exocomet Fragments or Aliens?

The paper from the Royal Astronomical Society is pretty straightforward regarding  the fluctuating light around a distant exoplanet called KIC 8462852 as spotted by the Kepler Space Telescope:

Over the duration of the Kepler mission, KIC 8462852 was observed to undergo irregularly shaped, aperiodic dips in flux down to below the 20% level. The dipping activity can last for between 5 and 80 days. We characterize the object with high-resolution spectroscopy, spectral energy distribution fitting, and Fourier analyses of the Kepler light curve. We determine that KIC 8462852 is a main-sequence F3 V/IV star, with a rotation period ~0.88 d, that exhibits no significant IR excess. In this paper, we describe various scenarios to explain the mysterious events in the Kepler light curve, most of which have problems explaining the data in hand. By considering the observational constraints on dust clumps orbiting a normal main-sequence star, we conclude that the scenario most consistent with the data is the passage of a family of exocomet fragments, all of which are associated with a single previous breakup event. We discuss the necessity of future observations to help interpret the system.

However, some see an alien presence, as they did with "canals" on Mars and recent "lights" on Ceres. So we have speculation about an alien megastructure harnessing energy from the star. 

Ross Andersen in The Atlantic writes:

Jason Wright, an astronomer from Penn State University, is set to publish an alternative interpretation of the light pattern. SETI researchers have long suggested that we might be able to detect distant extraterrestrial civilizations, by looking for enormous technological artifacts orbiting other stars. Wright and his co-authors say the unusual star’s light pattern is consistent with a “swarm of megastructures,” perhaps stellar-light collectors, technology designed to catch energy from the star.

Sci fi aside, we need to remain open-minded yet careful if we are to search the galaxy and beyond to know it better. And if we presume we are not alone, then the myriad of ways in which alien life might exist will always be part of the mystery before us. Hence, I am skeptical about a new megastructure but interested in learning more about this anomaly. 

Kepler: The Planet Finder

I really should have put the Kepler Space Telescope on my list of Great Accomplishments in 2012 since the little spacecraft was very busy in 2012 identifying more possible Earth-like planets in our galaxy. Launched in March 2009, Kepler has already investigated the brightness of more than 150,000 stars, identified more than 2,400 planet candidates, and confirmed more than 100 planets.  Many of these planets are Earth-sized and many are within the "habitable zone."  As part of its next mission, Kepler will begin to focus on Earth-like candidates in 1-year orbits around stars similar to our sun. 

At a January 7, 2013, press conference during the American Astronomical Society Meeting in Long Beach, CA, we learned that we are far from alone:

A new analysis of Kepler data shows that about 17 percent of stars have an Earth-sized planet in an orbit closer than Mercury. Since the Milky Way has about 100 billion stars, there are at least 17 billion Earth-sized worlds out there.

This is a pretty amazing discovery from this little spacecraft.  We went from guessing about our lonely status only a few years back to confirming that we are only one of billions of planets in a similar scenario - talk about a "Kepler moment."  Carl Sagan's book Cosmos provides this quote from the first Kepler that sums it up:

We do not ask for what useful purpose the birds do sing, for song is their pleasure since they were created for singing. Similarly, we ought not to ask why the human mind troubles to fathom the secrets of the heavens. The diversity of the phenomena of nature is so great and the treasures hidden in the heavens so rich precisely in order that the human mind shall never be lacking in fresh nourishment.

You can get more information on this latest announcement by viewing the accompanying paper on Kepler.