As a child in the 1950s, Jill Tarter would gaze at the stars and wonder, “Are we alone?” That monumental question has driven the astronomer's lifelong quest to find alien life in the Milky Way.
There’s no denying the fundamentally alien climates on the hot Jupiters. It’s not clear, however, how hot Jupiters form, and it’s not clear why so many of them are badly distended. Moreover, it’s only vaguely clear what the weather patterns on one would look like up close. (One thing that is clear is that the flights would all be canceled).
I have previously written about WFIRST (Summer 2015 Planetary Report). This NASA mission, planned to launch into space in the mid-2020s will have a coronagraph at least 1,000 times more powerful than any existing coronagraph. The power of a coronagraph is measured by the 'contrast ratio'—the ratio of the brightness of the central star to the brightness of the planet being studied. Current coronagraphs have a contrast ratio of about 100,000-1 million, which means that astronomers can see objects that are 100,000-1 million times dimmer (less bright) than the central star. WFIRST is being designed to achieve a contrast ratio of one billion to one! The primary difficulty in designing any coronagraph is in blocking all of the starlight. Once light has entered the telescope, it is extremely difficult to block it all with a coronagraph, partly due to a process called 'diffraction.' This is a process in which light is bent around corners or is scattered at the edges of objects. An analogy would be when you close the curtains, but there is a little gap and the light spreads as it passes through the small gap. In a telescope, this scattered light sometimes finds its way to the camera recording the telescope observations. So, achieving a contrast ratio of one billion to one requires us to keep that scattered light level very, very low.
This is the most comprehensive and detailed catalog release of candidate exoplanets, which are planets outside our solar system, from Kepler's first four years of data. It's also the final catalog from the spacecraft's view of the patch of sky in the Cygnus constellation.NASA's Kepler space telescope team has released a mission catalog of planet candidates that introduces 219 new planet candidates, 10 of which are near-Earth size and orbiting in their star's habitable zone, which is the range of distance from a star where liquid water could pool on the surface of a rocky planet.With the release of this catalog, derived from data publically available on the NASA Exoplanet Archive, there are now 4,034 planet candidates identified by Kepler. Of which, 2,335 have been verified as exoplanets. Of roughly 50 near-Earth size habitable zone candidates detected by Kepler, more than 30 have been verified.
Decryption of Messages from Extraterrestrial Intelligence Using the Power of Social Media - The SETI Decrypt Challenge
Authors:
Heller et al
Abstract:
With the advent of modern astronomy, humans might now have acquired the technological and intellectual requirements to communicate with other intelligent beings beyond the solar system, if they exist. Radio signals have been identified as a means for interstellar communication about 60 years ago. And the Square Kilometer Array will be capable of detecting extrasolar radio sources analogous to terrestrial high-power radars out to several tens of light years. The ultimate question is: will we be able to understand the message, or, vice versa, if we submit a message to extraterrestrial intelligence first, how can we make sure that they understand us? Here I report on the largest blind experiment of a pretend radio message received on Earth from beyond the solar system. I posted a sequence of about two million binary digits ("0" and "1") to the social media that encoded a configuration frame, two slides with mathematical content, and four images along with spatial and temporal information about their contents. Six questions were asked that would need to be answered to document the successful decryption of the message. Within a month after the posting, over 300 replies were received in total, including comments and requests for hints, 66 of which contained the correct solutions. About half of the solutions were derived fully independently, the other half profited from public online discussions and spoilers. This experiment demonstrates the power of the world wide web to help interpreting possible future messages from extraterrestrial intelligence and to test decryptability of our own deliberate interstellar messages.
An international team of astronomers using the Atacama Large Millimeter/submillimeter Array (ALMA) has made the first complete millimeter-wavelength image of the ring of dusty debris surrounding the young star Fomalhaut. This remarkably well-defined band of rubble and gas is likely the result of exocomets smashing together near the outer edges of a planetary system 25 light-years from Earth.
Earlier ALMA observations of Fomalhaut -- taken in 2012 when the telescope was still under construction - revealed only about one half of the debris disk. Though this first image was merely a test of ALMA's initial capabilities, it nonetheless provided tantalizing hints about the nature and possible origin of the disk.
Is there anybody out there?
Authors:
Anchordoqui et al
Abstract:
The Fermi paradox is the discrepancy between the strong likelihood of alien intelligent life emerging (under a wide variety of assumptions) and the absence of any visible evidence for such emergence. We use this intriguing unlikeness to derive an upper limit on the fraction of living intelligent species that develop communication technology \langle \xi_{\rm biotec} \rangle. \langle \cdots \rangle indicates average over all the multiple manners civilizations can arise, grow, and develop such technology, starting at any time since the formation of our Galaxy in any location inside it. Following Drake, we factorize \langle \xi_{\rm biotec} \rangle as the product of the fractions in which: (i) life arises, (ii) intelligence develops, and (iii) communication technology is developed. In this approximation, the number of communicating intelligent civilizations that exist in the Galaxy at any given time is found to be N = \langle \zeta_{\rm astro} \rangle \langle \xi_{\rm biotec} \rangle L_\tau, where \langle \zeta_{\rm astro} \rangle is the average production rate of potentially habitable planets with a long-lasting (\sim 4 Gyr) ecoshell and L_\tau is the length of time that a typical civilization communicates. We estimate the production rate of exoplanets in the habitable zone and using recent determinations of the rate of gamma-ray bursts (GRBs) and their luminosity function, we calculate the probability that a life-threatening (lethal) GRB could make a planet inhospitable to life, yielding \langle \zeta_{\rm astro} \rangle \sim 2 \times 10^{-3}. Our current measurement of N =0 then implies \langle \zeta_{\rm biotec} \rangle < 5 \times 10^{-3} at the 95\% C.L., where we have taken L_\tau > 0.3 Myr such that c L_\tau >> propagation distances of Galactic scales (\sim 10 kpc), ensuring that any advanced civilization living in the Milky Way would be able to communicate with us.
