Michael Castelaz finds MMO photometry supports Schaefer claim of century-long dimming of #TabbysStar@tsboyajian @hippke pic.twitter.com/N4wpIVGJCf
— Jason Wright (@Astro_Wright)January 11, 2018
“Traditional SETI is not part of astrobiology” declares the NASA Astrobiology Strategy 2015 document. This is incorrect. In this white paper, I argue that SETI−seen as the search for technosignatures characteristic of the future of life in the universe−is a neglected complement to the search for biosignatures in NASA’s astrobiology portfolio, and may offer the more fruitful avenue to the discovery of life elsewhere in the universe, as recognized by the Astro2010 decadal survey. I rebut six erroneous perceptions that may contribute to the field’s absence from NASA’s astrobiology strategy, and argue that since SETI is, quite obviously, part of astrobiology, SETI practitioners should at the very least be expressly encouraged to compete on a level playing field with practitioners of other subfields for NASA astrobiology resources.
The $10 billion telescope underwent tests inside Chamber A at Johnson Space Center, which was built in 1965 to conduct thermal-vacuum testing on the Apollo command and service modules. Beginning in mid-July, after the telescope was cooled down to a temperature range of 20 to 40 Kelvin, engineers tested the alignment of Webb’s 18 primary mirror segments to ensure they would act as a single, 6.5-meter telescope. (They did).
Later, they assessed the fine guidance system of the telescope by simulating the light of a distant star. The Webb telescope was able to detect the light, and all of the optical systems were able to process it. Then, the telescope was able to track the “star” and its movement, giving scientists confidence that the Webb instrument will work once in space.
Webb still has a ways to go before it launches. Now that project scientists know that the optic portion of the instrument can withstand the vacuum of space, and the low temperatures at the Earth-Sun L2 point it will orbit in deep space, they must perform additional testing before a probable launch next year.
Titled “Three Versions of the Third Law: Technosignatures and Astrobiology,” the document makes the case that there has arisen an artificial distinction between astrobiology and SETI, with the former deemed acceptable for funding in ways that SETI has often not been, given the controversies in its history. As evidence, take the current 2015 NASA Astrobiology Strategy document, which baldly states: “While traditional Search for Extraterrestrial Intelligence (SETI) is not part of astrobiology, and is currently well-funded by private sources, it is reasonable for astrobiology to maintain strong ties to the SETI community.”
Strong ties are good, surely, but the distinction is artificial. In what sense is SETI not part of astrobiology? As the white paper notes, the Galileo flyby described by Carl Sagan and fellow authors in a 1993 paper in Nature found that a critical lifemarker (for both life itself and intelligent life) was the presence of narrow-band, pulsed, amplitude modulated radio signals. This is the kind of data rejected by the exclusion of SETI from astrobiology.
In the weeks following that Christmas detection, Arecibo registered 15 more bursts from this one source. These flashes were the highest frequency FRBs ever captured at the time, a measurement made possible by the hardware Seymour and his team had just installed. Based on the new information, the scientists have concluded in a study released today in the journal Nature that whatever object is creating the bursts, it must be in a very odd and extreme cosmic neighborhood, something akin to the environment surrounding a black hole with a mass of more than 10,000 suns.
We present a photometric detection of the first brightness dips of the unique variable star KIC 8462852 since the end of the Kepler space mission in 2013 May. Our regular photometric surveillance started in October 2015, and a sequence of dipping began in 2017 May continuing on through the end of 2017, when the star was no longer visible from Earth. We distinguish four main 1-2.5% dips, named “Elsie,” “Celeste,” “Skara Brae,” and “Angkor”, which persist on timescales from several days to weeks. Our main results so far are: (i) there are no apparent changes of the stellar spectrum or polarization during the dips; (ii) the multiband photometry of the dips shows differential reddening favoring non-grey extinction. Therefore, our data are inconsistent with dip models that invoke optically thick material, but rather they are in-line with predictions for an occulter consisting primarily of ordinary dust, where much of the material must be optically thin with a size scale <<1um, and may also be consistent with models invoking variations intrinsic to the stellar photosphere. Notably, our data do not place constraints on the color of the longer-term “secular” dimming, which may be caused by independent processes, or probe different regimes of a single process.
Scientists with the University of Chicago have laid out a comprehensive theory for how our solar system could have formed in the wind-blown bubbles around a giant, long-dead star. Published Dec. 22 in the Astrophysical Journal, the study addresses a nagging cosmic mystery about the abundance of two elements in our solar system compared to the rest of the galaxy.
The general prevailing theory is that our solar system formed billions of years ago near a supernova. But the new scenario instead begins with a giant type of star called a Wolf-Rayet star, which is more than 40 to 50 times the size of our own sun. They burn the hottest of all stars, producing tons of elements which are flung off the surface in an intense stellar wind. As the Wolf-Rayet star sheds its mass, the stellar wind plows through the material that was around it, forming a bubble structure with a dense shell.
A team of astronomers from Maryland, Hawaiʻi, Israel and France has produced the most detailed map ever of the orbits of galaxies in our extended local neighborhood, showing the past motions of almost 1,400 galaxies within 100 million light years of the Milky Way.
The team, including co-author Brent Tully of the Institute for Astronomy at the University of Hawaiʻi, reconstructed the galaxies’ motions from 13 billion years in the past to the present day. The main gravitational attractor in the mapped area is the Virgo Cluster, with 600 trillion times the mass of the Sun, 50 million light years from us.
“The more I study this object, the more unusual it appears, making me wonder whether it might be an artificially made probe which was sent by an alien civilization,” Avi Loeb, the chair of Harvard’s astronomy department and one of Milner’s advisers on Breakthrough Listen, wrote in the email to Milner.
[…]
‘Oumuamua’s discoverers in Hawaii have said their observations are “entirely consistent with it being a natural object.” Analysis of the light reflected by the asteroid shows ‘Oumuamua is red, a color that would be expected for rocky bodies exposed to the cosmic radiation of interstellar space for long periods of time.
[…]
If ‘Oumuamua has anything exciting to tell us, it’s that our understanding of planet formation needs some work, said Gregory Laughlin, an astronomer who studies exoplanets at Yale University.“We know that planetary systems are extremely common, but the way that their process unfolds seems to be richer than anticipated,” he said.
It weighs as much as 780 million suns and helped to cast off the cosmic Dark Ages. But now that astronomers have found the earliest known black hole, they wonder: How could this giant have grown so big, so fast?
Earlier this year, the National Science Foundation’s Very Long Baseline Array telescope turned its gaze to NASA’s famed Voyager 1 and captured an image of this iconic spacecraft’s faint radio signal. The Green Bank Telescope also detected Voyager’s signal, picking it out from the background radio noise in less than one second.
Astronomers using the National Science Foundation’s (NSF) Very Long Baseline Array (VLBA) and Green Bank Telescope (GBT) spotted the faint radio glow from NASA’s famed Voyager 1 spacecraft — the most distant man-made object.
According to NASA’s Jet Propulsion Laboratory (JPL), the VLBA imaged the signal from Voyager 1’s main transmitter after the spacecraft had already passed beyond the edge of the heliosphere, the bubble of charged particles from the Sun that surrounds our Solar System.
This paper presents V- and g’-band observations of the F2V star KIC 8462852, which exhibited enigmatic fade patterns in Kepler mission data. We introduce a transit simulation model for interpretation of these fades, and use it to interpret an August 2017 dip as a repeat of the Kepler day 1540 dip (D1540). We suggest the August 2017 and D1540 dips may be caused by a brown dwarf and an associated ring system in a 1601-day elliptical orbit. Transiting icy moons of the proposed brown dwarf, sublimating near periapsis like comets, could provide an explanation for the significant dips observed by Kepler, as well as the recent May to October 2017 dips and the long term variation in flux detected by Simon et al. (2017). Whereas the presence of such a ring structure is attractive for its ability to explain short term fade events, we do not address how such a ring system can be created and maintained. If our speculation is correct, a brightening of about 1-2 percent should occur during October to November 2017. In addition, this scenario predicts that a set of dimming events, similar to those in 2013 (Kepler) and in 2017 (reported here), can be expected to repeat during October 2021 to January 2022 and a repeat of D1540 should occur on 27 December 2021.
What a lucky shot! While astrophotographer Fritz Helmut Hemmerich was capturing an image of the Andromeda galaxy, a sand-sized rock from deep space crossed right in front of the camera creating this incredible green streak. Or it was just aliens. 👽
Late last year, Kraan-Korteweg and colleagues announced that they had discovered an enormous cosmic structure: a “supercluster” of thousands upon thousands of galaxies. The collection spans 300 million light years, stretching both above and below the galactic plane like an ogre hiding behind a lamppost. The astronomers call it the Vela Supercluster, for its approximate position around the constellation Vela.
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