Would Aliens Spot Our Planet from the Star System Nearby? NASA Answers on Reddit

If we were aliens, would we be able to detect Earth using the technology we have now?

This was one of the questions answered by NASA’s Kepler team, consisting of SETI researchers, during an “Ask Me Anything” (AMA) event Monday on Reddit Science forum. “If the aliens on Proxima Centauri had the same technology as us they would be very close to being able to directly image Earth,” Jason Rowe, Kepler mission team member of the SETI Institute answered. “A few research groups, including researchers at NASA-Ames and SETI, are actively developing chronographic and high-resolution technology that will enable direct detection of Earth-like planets around nearby stars.”

Kepler is NASA’s first mission to find and confirm small Earth-size planets around other stars in the habitable zone (the range of distance from a star where liquid water might pool on the surface of an orbiting planet).

Reddit has a sub-forum for interviews with volunteers who answer questions about their specific experiences. On one of the “Science AMA Series” sub-forums, the scientists were answering questions for about two hours regarding Kepler, its extended K2 mission, and planet-hunting activities overall. “We do this work in order to answer these questions for the general public,” Susan Thompson of the SETI Institute wrote. “By showing us your interest, you help drive us and NASA to continue to do this kind of research.”

To date, Kepler has identified more than 4,200 exoplanet candidates and verified nearly 1,000 as bonafide planets. Through Kepler discoveries, planets are now known to be common and diverse, showing the universe hosts a vast range of environments. “The most interesting exoplanet we have found so far is Kepler-186f, the Earth cousin. This planet is just 10% larger than Earth, is in the habitable zone of its star and might have water in liquid form,” SETI’s engineer, Anima Patil-Sabale revealed. “Even though it orbits a M-Dwarf type star, it is a habitable planet that is closest to the Kepler Mission objective of finding an Earth twin.”

After the failure of two of its four reaction wheels following the completion of data collection in its primary mission, the Kepler spacecraft was resuscitated this year and reborn as K2, a mission that extends the Kepler legacy to observations in the ecliptic – the part of the sky that is home to the familiar constellations of the zodiac. The K2 mission will continue exoplanet discovery, and introduces new scientific observation opportunities to study notable star clusters, young and old stars, active galaxies and supernovae. “Our best guess at the moment is that K2 can keep running until it runs out of fuel which gives us maybe 2-5 years, depending,” SETI Institute scientist, Fergal Mullally noticed.
At the dawn of Kepler planet-hunting era, the scientist also discussed new possibilities to discover extrasolar celestial bodies. “NASA is currently developing an all-sky transit survey mission called TESS (Transiting Exoplanet Survey Satellite) that will launch in 2017 to search for Earth’s closest cousins,” Jon Jenkins, Kepler mission co-investigator wrote. “The primary goal of this mission is to find at least 50 small planets for which we can get mass measurements and these would then be great planets for follow up and characterization with assets such as James Webb Space Telescope and other large (huge) telescopes that will be available in the near future.”

Exoplanet topics were followed by questions about careers in NASA, SETI research teams. NASA’s co-creator of the education and public outreach program, Alan Gould, admitted that astronomy is not the only career type needed for Kepler or other research teams. Engineering, computer programming, business services, are also needed. But in general, one needs a really solid background in mathematics as well as science, he added.

The NASA Kepler AMA was part of the Bay Area Science Festival, a 10-day celebration of science and technology in the San Francisco Bay Area.

via: http://bit.ly/1zNR4lB


Most planets in the Universe are homeless

"Think about the fact that our own solar system contains hundreds or even thousands of objects that potentially meet the geophysical definition of a planet, but are astronomically excluded only by the virtue of their orbital location. Now consider that for every star like our Sun, there are most likely hundreds of failed stars that simply didn’t accrue enough mass to ignite fusion in their core. These are the homeless planets — or rogue planets — that far outnumber planets like ours, that orbit stars. They may or may not have atmospheres, and they may be incredibly difficult to detect, especially the (theoretically) more common ones: the smallest objects. But if you do the math, that means for every star-orbiting planet like ours in the galaxy, there may be up to 100,000 planets that not only don’t orbit one now, but most likely never did."

We like to think of our Solar System as typical: a central star with a number of planets — some gas giants and some rocky worlds — in orbit around it. Yes, there’s some variety, with binary or trinary star systems and huge variance in the masses of the central star being common ones, but from a planetary point of view, our Solar System is a rarity. Even though there are hundreds of billions of stars in our galaxy for planets to orbit, there are most likely around a quadrillion planets in our galaxy, total, with only a few trillion of them orbiting stars at most.

Gliese 832c: The closest potentially habitable exoplanet

This planet is only 16 light years away — could it harbor life? Recently discovered exoplanet Gliese 832c has been found in a close orbit around a star that is less bright than our Sun. An interesting coincidence, however, is that Gliese 832c receives just about the same average flux from its parent star as does the Earth. Since the planet was discovered only by a slight wobble in its parent star’s motion, the above illustration is just an artistic guess of the planet’s appearance — much remains unknown about Gliese 832c’s true mass, size, and atmosphere. If Gliese 832c has an atmosphere like Earth, it may be a super-Earth undergoing strong seasons but capable of supporting life. Alternatively, if Gliese 832c has a thick atmosphere like Venus, it may be a super-Venus and so unlikely to support life as we know it. The close 16-light year distance makes the Gliese 832 planetary system currently the nearest to Earth that could potentially support life. The proximity of the Gliese 832 system therefore lends itself to more detailed future examination and, in the most spectacularly optimistic scenario, actual communication — were intelligent life found there.

Image credit & copyright: The Planetary Habitability Laboratory @ UPR Arecibo; Discovery: Robert A. Wittenmyer (UNSW Australia) et al.

The Formation and Dynamics of Super-Earth Planets

Super-Earths, objects slightly larger than Earth and slightly smaller than Uranus, have found a special place in exoplanetary science. As a new class of planetary bodies, these objects have challenged models of planet formation at both ends of the spectrum and have triggered a great deal of research on the composition and interior dynamics of rocky planets in connection to their masses and radii.

Being relatively easier to detect than an Earth-sized planet at 1 AU around a G star, super-Earths have become the focus of worldwide observational campaigns to search for habitable planets. With a range of masses that allows these objects to retain moderate atmospheres and perhaps even plate tectonics, super-earths may be habitable if they maintain long-term orbits in the habitable zones of their host stars. Given that in the past two years a few such potentially habitable super-Earths have in fact been discovered, it is necessary to develop a deep understanding of the formation and dynamical evolution of these objects.

This article reviews the current state of research on the formation of super-Earths and discusses different models of their formation and dynamical evolution.

Image Credit: ESO/M. Kornmesser