KREUZADER (Posts tagged astronomy)

That is not dead which can eternal lie: the aestivation hypothesis for resolving Fermi’s paradox“ If a civilization wants to maximize computation it appears rational to aestivate until the far future in order to exploit the low temperature... — That is not dead which can eternal lie: the aestivation hypothesis for resolving Fermi’s paradox
If a civilization wants to maximize computation it appears rational to aestivate until the far future in order to exploit the low temperature environment: this can produce a 10³⁰ multiplier of achievable computation. We hence suggest the “aestivation hypothesis”: the reason we are not observing manifestations of alien civilizations is that they are currently (mostly) inactive, patiently waiting for future cosmic eras. This paper analyzes the assumptions going into the hypothesis and how physical law and observational evidence constrain the motivations of aliens compatible with the hypothesis.

Source: arxiv.org

seti exobiology extraterrestrial intelligence astronomy

‘Rogue Planets’ Are Roaming Our Galaxy“ But there are some worlds that wander the Milky Way as solar exiles, catapulted from their native systems by interloping objects or cataclysmic events. Others are born in the interstellar medium without a... — ‘Rogue Planets’ Are Roaming Our Galaxy
But there are some worlds that wander the Milky Way as solar exiles, catapulted from their native systems by interloping objects or cataclysmic events. Others are born in the interstellar medium without a parent star. These planets, with no sun of their own, go by many names—rogues, nomads, orphans—and there are estimated to be billions of them adrift in our Milky Way, sparking the imaginations of scientists and science fiction fans alike.
Such free-floating places are shrouded in mystery relative to their star-anchored peers, because they lurk in the shadows of the galaxy, and leave few traces of their presence. But they are not entirely undetectable, as demonstrated by new research published on Monday in *Nature*.
Scientists led by Przemek Mróz, a PhD student at Warsaw University Observatory, analyzed the light curves of nearly 50 million stars observed between 2010 and 2015 by the Optical Gravitational Lensing Experiment (OGLE) at Las Campanas Observatory in Chile.
[…]
The new study found that Jupiter-scale rogue planets are far rarer than what had been suggested in the 2011 study, with an estimated upper limit of 25 Jupiter-mass objects per 100 main-sequence (fusion-capable) stars. This is about ten times lower than the 2011 results, Mróz told me over email, adding that the new number “is consistent with our expectations from planet formation theories."

Source: Vice Magazine

astronomy

Since 1995, Ghez, an astrophysicist at the University of California, Los Angeles, has used the W.M. Keck telescope on Mauna Kea in Hawaii to see fine details at the center of the galaxy. The observations that Ghez has made of stars racing around the Milky Way’s core (alongside those of rival Reinhard Genzel, an astrophysicist at the Max Planck Institute for Astrophysics in Garching, Germany) have proven to most astronomers that the central object can be nothing but a black hole. But to be able to see these fine details, Ghez had to become a pioneering user of adaptive optics, a technology that measures distortions in the atmosphere and then adjusts the telescope in real time to cancel out those fluctuations.

Source: quantamagazine.org

astronomy astrophyics black hole

“On June 25, 2016 at 6pm ET, a flash of visible light appeared in the sky that, depending on your location, could have been visible with binoculars. It wasn’t a plane or a star: it was a gamma ray burst, one of the most violent kinds of explosions in... — On June 25, 2016 at 6pm ET, a flash of visible light appeared in the sky that, depending on your location, could have been visible with binoculars. It wasn’t a plane or a star: it was a gamma ray burst, one of the most violent kinds of explosions in the universe, from a source 9 billion light years away, possibly a black hole.
[…]
This gamma ray burst, named GRB 160625B, was special. NASA’s Fermi Gamma-ray Space Telescope gamma ray burst monitor picked it up, and just three minutes later its Large Area Telescope started monitoring the location. The telescope watched the light show happen live and evolve over time. That was a new type of observation that could help scientists understand exactly what causes these massive bursts.
[…]
This light most likely originated from collimated jets of particles spewing from a young black hole. The polarized nature of the light means that the area around the black hole could have had a strong magnetic field, which would be an important piece of information missing from observations but present in theories, said Troja. “That’s the only thing that can explain the polarization and all the data we collected.”

Source: Gizmodo

black hole gamma ray burst astronomy astrophysics

Large asteroid comes 1/3 Moon distance. Gets its orbit bent by Earth. #2017OO1
click for simulation: https://t.co/K3crkSIHxw pic.twitter.com/lxwRha2k5s
— Tony Dunn (@tony873004)
July 26, 2017

Source: minorplanetcenter.net

asteroid planetary defense space astronomy

NASA-funded Citizen Science Project Discovers New Brown Dwarf
“A paper about the new brown dwarf was published on May 24 in The Astrophysical Journal Letters. Four citizen scientists are co-authors of the paper, including Castro. Since then, Backyard... — NASA-funded Citizen Science Project Discovers New Brown Dwarf
A paper about the new brown dwarf was published on May 24 in The Astrophysical Journal Letters. Four citizen scientists are co-authors of the paper, including Castro. Since then, Backyard Worlds: Planet 9 has identified roughly 117 additional brown dwarf candidates.
The collaboration was inspired by the recently proposed ninth planet, possibly orbiting at the fringes of our solar system beyond Pluto.
“We realized we could do a much better job identifying Planet Nine if we opened the search to the public,” said lead researcher Marc Kuchner, an astrophysicist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “Along the way, we’re hoping to find thousands of interesting brown dwarfs.”

Source: nasa.gov

astronomy nasa space

“After a careful analysis of the observations we performed last Sunday from the Arecibo Observatory, together with SETI Berkeley from the Green Bank Telescope and the SETI Institute’s ATA, we are now confident about the source of the Weird! Signal.... — After a careful analysis of the observations we performed last Sunday from the Arecibo Observatory, together with SETI Berkeley from the Green Bank Telescope and the SETI Institute’s ATA, we are now confident about the source of the Weird! Signal. The best explanation is that the signals are transmissions from one or more geostationary satellites. This explains why the signals were within the satellite’s frequencies and only appeared and persisted in Ross 128; the star is close to the celestial equator where many geostationary satellites are placed. This fact, though, does not yet explain the strong dispersion-like features of the signals (diagonal lines in the figure); however, It is possible that multiple reflections caused these distortions, but we will need more time to explore this and other possibilities.

Source: phl.upr.edu

astronomy radio astronomy

The Breakthrough Listen Search for Intelligent Life: A Wideband Data Recorder System for the Robert C. Byrd Green Bank Telescope“ The Breakthrough Listen Initiative is undertaking a comprehensive search for radio and optical signatures from... — The Breakthrough Listen Search for Intelligent Life: A Wideband Data Recorder System for the Robert C. Byrd Green Bank Telescope
The Breakthrough Listen Initiative is undertaking a comprehensive search for radio and optical signatures from extraterrestrial civilizations. An integral component of the project is the design and implementation of wide-bandwidth data recorder and signal processing systems. The capabilities of these systems, particularly at radio frequencies, directly determine survey speed; further, given a fixed observing time and spectral coverage, they determine sensitivity as well. Here, we detail the Breakthrough Listen wide-bandwidth data recording system deployed at the 100-m aperture Robert C. Byrd Green Bank Telescope. The system digitizes up to 6 GHz of bandwidth at 8 bits for both polarizations, storing the resultant 24 GB/s of data to disk. This system is among the highest data rate baseband recording systems in use in radio astronomy. A future system expansion will double recording capacity, to achieve a total Nyquist bandwidth of 12 GHz in two polarizations. In this paper, we present details of the system architecture, along with salient configuration and disk-write optimizations used to achieve high-throughput data capture on commodity compute servers and consumer-class hard disk drives.

Source: arxiv.org

radio astronomy astronomy radio seti breakthrough listen

Signals from A Nearby Star System?“In May, radio astronomers at the Arecibo radio telescope in Puerto Rico pointed their Brobdingnagian antenna in the direction of Ross 128. The researchers’ interest was to learn if they could measure any natural... — Signals from A Nearby Star System?
In May, radio astronomers at the Arecibo radio telescope in Puerto Rico pointed their Brobdingnagian antenna in the direction of Ross 128. The researchers’ interest was to learn if they could measure any natural radio emissions from this very close (11 light-years) dwarf. Such stars are known to act up, and the turbulent flares that erupt from their surfaces produce radio static. The hope was that small changes in such emission might offer clues to planets whose magnetic fields might perturb these stellar storms. (Note that Ross 128 does not have any known planets, but that doesn’t guarantee there aren’t any.
What the Puerto Rican astronomers found when the data were analyzed was a wide-band radio signal. This signal not only repeated with time, but also slid down the radio dial, somewhat like a trombone going from a higher note to a lower one.

Source: seti.org

seti astronomy radio astronomy

Strange Signals from the Nearby Red Dwarf Star Ross 128“Two weeks after these observations, we realized that there were some very peculiar signals in the 10-minute dynamic spectrum that we obtained from Ross 128 (GJ 447), observed May 12 at 8:53 PM... — Strange Signals from the Nearby Red Dwarf Star Ross 128
Two weeks after these observations, we realized that there were some very peculiar signals in the 10-minute dynamic spectrum that we obtained from Ross 128 (GJ 447), observed May 12 at 8:53 PM AST (2017/05/13 00:53:55 UTC). The signals consisted of broadband quasi-periodic non-polarized pulses with very strong dispersion-like features. We believe that the signals are not local radio frequency interferences (RFI) since they are unique to Ross 128 and observations of other stars immediately before and after did not show anything similar.
We do not know the origin of these signals but there are three main possible explanations: they could be (1) emissions from Ross 128 similar to Type II solar flares, (2) emissions from another object in the field of view of Ross 128, or just (3) burst from a high orbit satellite since low orbit satellites are quick to move out of the field of view. The signals are probably too dim for other radio telescopes in the world and FAST is currently under calibration.

Source: phl.upr.edu

astronomy radio astronomy seti

We go over the current normalized flux graph of Tabby’s star for July 15th, 2017 by reviewing a current flux graph provided by Dr. Tabby Boyajian. We also discuss the elephant in the room, which is namely the increasing error that is being observed in the normalized flux graphs and what we plan to do about it.

star keeps on being weird as hell

kic 8462852 boyajian's star astronomy

What Happens if We Detect Extraterrestrial Intelligence?““KIC 8462852 is a very, very interesting star. It’s a singular object in astronomy. We know of no other object—no other star—that is like it,” says Siemion. “So that makes it intrinsically very... — What Happens if We Detect Extraterrestrial Intelligence?
“KIC 8462852 is a very, very interesting star. It’s a singular object in astronomy. We know of no other object—no other star—that is like it,” says Siemion. “So that makes it intrinsically very exciting for astronomy, and, I think, also very exciting for SETI.”
The odds of finding intelligent life circling Boyajian’s Star (or any place else, for that matter) are, in a word, slim.
“It’s a one in a million shot,” says Boyajian, but “why not look?” After all, whether or not we’re alone in the universe is arguably the biggest question humanity faces.
But say that, one day, researchers actually do find a signal—either from Boyajian’s star or from somewhere else—and that other scientists verify it as the product of something undisputedly extraterrestrial and intelligent. Then what?

Source: sciencefriday.com

seti extraterrestrial intelligence astronomy space kic 8462852 boyajian's star

Exoplanet Transits as the Foundation of an Interstellar Communications Network“ Two fundamental problems for extraterrestrial intelligences (ETIs) attempting to establish interstellar communication are timing and energy consumption. Humanity’s study... — Exoplanet Transits as the Foundation of an Interstellar Communications Network
Two fundamental problems for extraterrestrial intelligences (ETIs) attempting to establish interstellar communication are timing and energy consumption. Humanity’s study of exoplanets via their transit across the host star highlights a means of solving both problems. An ETI ‘A’ can communicate with ETI 'B’ if B is observing transiting planets in A’s star system, either by building structures to produce artificial transits observable by B, or by emitting signals at B during transit, at significantly lower energy consumption than typical electromagnetic transmission schemes.
This can produce a network of interconnected civilisations, establishing contact via observing each other’s transits. Assuming that civilisations reside in a Galactic Habitable Zone (GHZ), I conduct Monte Carlo Realisation simulations of the establishment and growth of this network, and analyse its properties in the context of graph theory.

Source: arxiv.org

seti astronomy

Another Possibility for Boyajian’s Star“The unusual light curve of the star KIC 8462852, also known as “Tabby’s star” or “Boyajian’s star”, has puzzled us since its discovery last year. A new study now explores whether the star’s missing flux is due... — Another Possibility for Boyajian’s Star
The unusual light curve of the star KIC 8462852, also known as “Tabby’s star” or “Boyajian’s star”, has puzzled us since its discovery last year. A new study now explores whether the star’s missing flux is due to *internal* blockage rather than something *outside* of the star.
[…]
Decades ago, researchers discovered that our own star’s total flux isn’t as constant as we thought. When magnetic dark spots on the Sun’s surface block the heat transport, the Sun’s luminosity dips slightly. The diverted heat is redistributed in the Sun’s interior, becoming stored as a very small global heating and expansion of the convective envelope. When the blocking starspot is removed, the Sun appears slightly brighter than it did originally. Its luminosity then gradually relaxes, decaying back to its original value.
Foukal recognized that this phenomenon may also provide an explanation for Boyajian’s star. He modeled how this might occur for Boyajian’s star, demonstrating that if its flux is somehow blocked from reaching the surface and stored in a shallow convective zone, this can account for the 20% dips seen in the star’s light curve.

Source: aasnova.org

astronomy astrophysics kic 8462852 boyajian's star

The Strangest (and Second-Strangest) Star in the Galaxy“Wright, an astronomer at Penn State, is one of the lead scientists investigating the strangely flickering object commonly known as Tabby’s Star or, in the popular press, as the “alien... — The Strangest (and Second-Strangest) Star in the Galaxy
Wright, an astronomer at Penn State, is one of the lead scientists investigating the strangely flickering object commonly known as Tabby’s Star or, in the popular press, as the “alien megastructure star.” The star’s behavior is so puzzling that Wright included among the possible explanations that a huge construction project is orbiting around it. (Note that he never suggested aliens were the best explanation, merely that the hypothesis could not yet be ruled out.) Lately Tabby’s Star has been acting up again, providing intriguing new data but, so far, still no definitive answers.
While Tabby’s Star continues to vex and excite the astronomical community, Wright is busy thinking about other puzzles as well. I was particularly intrigued by another misbehaving star, by the mouthy name of Przybylski’s Star (pronounced “jebilskee,” roughly). If Tabby’s Star is the most mysterious star in our galaxy–an epithet endorsed by Tabetha Boyajian, who first described the star’s irregularities–then Przybylski’s Star may qualify as the second-most strange and mysterious star around. In this case the puzzle is the star’s composition, which appears to be filled with radioactive actinides, short-lived elements normally found only in nuclear experiments on Earth.

astronomy boyajian's star kic 8462852

KREUZADER (Posts tagged astronomy)

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