This is pretty interesting... an asteroid of possible interstellar origin has been found in a stable, retrograde solar orbit near Jupiter. The authors' simulations show the object could have been captured during the formation of the solar system. The actual paper is behind a paywall, unfortunately, but you can read the abstract by following a link at the end of the article below.https://phys.org/news/2018-05-interstellar-immigrant-solar.html
Quote from: jgoldader on 05/21/2018 01:06 pmThis is pretty interesting... an asteroid of possible interstellar origin has been found in a stable, retrograde solar orbit near Jupiter. The authors' simulations show the object could have been captured during the formation of the solar system. The actual paper is behind a paywall, unfortunately, but you can read the abstract by following a link at the end of the article below.https://phys.org/news/2018-05-interstellar-immigrant-solar.htmlThe argument for this being interstellar seems rather weaker than many of the headlines suggest. Some comments from other researchers in Lee Billings sciam articlehttps://www.scientificamerican.com/article/astronomers-spot-potential-interstellar-asteroid-orbiting-backward-around-the-sun/Batygin of course suggests Planet 9 as an alternative
Asteroid (514107) 2015 BZ509 was discovered recently in Jupiter's co-orbital region with a retrograde motion around the Sun. The known chaotic dynamics of the outer Solar System have so far precluded the identification of its origin. Here, we perform a high-resolution statistical search for stable orbits and show that asteroid (514107) 2015 BZ509 has been in its current orbital state since the formation of the Solar System. This result indicates that (514107) 2015 BZ509 was captured from the interstellar medium 4.5 billion years in the past as planet formation models cannot produce such a primordial large-inclination orbit with the planets on nearly-coplanar orbits interacting with a coplanar debris disk that must produce the low-inclination small-body reservoirs of the Solar System such as the asteroid and Kuiper belts. This result also implies that more extrasolar asteroids are currently present in the Solar System on nearly-polar orbits.
The team reviewed studies of fossils on Earth and assessed the results of lab experiments replicating Martian conditions to identify the most promising sites on the planet to explore for traces of ancient life.Their findings could help inform NASA’s next rover mission to the Red Planet, which will focus on searching for evidence of past life. The US space agency’s Mars 2020 rover will collect rock samples to be returned to Earth for analysis by a future mission. A similar mission led by the European Space Agency is also planned in coming years.The latest study could aid in the selection of landing sites for both missions, and help identify the best places to gather rock samples.The study, published in Journal of Geophysical Research, also involved researchers at NASA’s Jet Propulsion Laboratory, Brown University, California Institute of Technology, Massachusetts Institute of Technology and Yale University in the US.
Astronomers have proposed a new model for the invisible material that makes up most of the matter in the Universe. They have studied whether a fraction of dark matter particles may have a tiny electrical charge."You've heard of electric cars and e-books, but now we are talking about electric dark matter," said Julian Munoz of Harvard University in Cambridge, Mass., who led the study that has been published in the journal Nature. "However, this electric charge is on the very smallest of scales."Munoz and his collaborator, Avi Loeb of the Harvard-Smithsonian Center for Astrophysics (CfA) in Cambridge, Mass., explore the possibility that these charged dark matter particles interact with normal matter by the electromagnetic force.
Next astro decadal will not be delayed:http://spacenews.com/nasa-drops-request-to-delay-next-astrophysics-decadal/
He added he was also concerned that the decadal, whenever it takes place, reflect the diversity of the astrophysics research community. “[A] strategy cannot be important if it is put together by representatives of the top-10 University programs, and by a community group that is all male and has an average age north of 65!” he wrote. “Diverse groups make better strategies, and provide better alignment and buy-in.”
Quote from: Blackstar on 05/31/2018 01:20 pmNext astro decadal will not be delayed:http://spacenews.com/nasa-drops-request-to-delay-next-astrophysics-decadal/Interesting quote from the article:QuoteHe added he was also concerned that the decadal, whenever it takes place, reflect the diversity of the astrophysics research community. “[A] strategy cannot be important if it is put together by representatives of the top-10 University programs, and by a community group that is all male and has an average age north of 65!” he wrote. “Diverse groups make better strategies, and provide better alignment and buy-in.”I know this is a sensible topic, so I'll try my best to communicate as civil as possible my worries.I thought the general unspoken rule for scientist was to not insert their personal politics in their methodology. Considering the fact that we are talking about multibillion dollar endeavors payed for by taxpayer money you would think the first concern should be to get the most qualified (based on academic merit and prior experience) persons to design these missions and bot prioritize based on arbitrary ideological reasoning, like gender, age or ethnicity. For example, I don't think it's wise to try to give equal say in planning between a 24 yr old undergrad and a 68 yr old who was involved in several other missions. We already know how some of these flagship telescopes can have their costs balloon out of control (looking at you JWST), I don't think the science directorate has any wiggle room to reject certain participants because they are male or over 65 if they prove to be the most qualified to carry a given task.I am worried about this kind of reasoning because over the last to years there have been a couple of times when the same "issue" was brought up at different meetings, and I was wondering if there is any backlash within the astrophysics and planetary scientific communities for what (to me at least) looks like a dangerous pushing of a fringe political dogma in government funded science. I know that those soon to retire might be somewhat indifferent, but I am curious if the younger counterparts are worried about possible discrimination and questioning this push for diversity became taboo.
So could you not possibly start a thread in political policy which is where if anywhere this topic belongs.
(Abstract)The Kepler mission found hundreds of planet candidates within the habitable zones (HZ) of their host star, including over 70 candidates with radii larger than 3 Earth radii (R⊕) within the optimistic habitbale zone (OHZ) (Kane et al. 2016). These giant planets are potential hosts to large terrestrial satellites (or exomoons) which would also exist in the HZ. We calculate the occurrence rates of giant planets (Rp=~3.0--25~R⊕) in the OHZ and find a frequency of (6.5±1.9)% for G stars, (11.5±3.1)% for K stars, and (6±6)% for M stars. We compare this with previously estimated occurrence rates of terrestrial planets in the HZ of G, K and M stars and find that if each giant planet has one large terrestrial moon then these moons are less likely to exist in the HZ than terrestrial planets. However, if each giant planet holds more than one moon, then the occurrence rates of moons in the HZ would be comparable to that of terrestrial planets, and could potentially exceed them. We estimate the mass of each planet candidate using the mass-radius relationship developed by Chen & Kipping (2016). We calculate the Hill radius of each planet to determine the area of influence of the planet in which any attached moon may reside, then calculate the estimated angular separation of the moon and planet for future imaging missions. Finally, we estimate the radial velocity semi-amplitudes of each planet for use in follow up observations.
During the peak of their accretion phase, supermassive black holes in galactic cores are known to emit very high levels of ionizing radiation, becoming visible over intergalactic distances as quasars or active galactic nuclei (AGN). Here, we quantify the extent to which the activity of the supermassive black hole at the center of the Milky Way, known as Sagittarius A* (Sgr A*), may have affected the habitability of Earth-like planets in our Galaxy. We focus on the amount of atmospheric loss and on the possible biological damage suffered by planets exposed to X-ray and extreme ultraviolet (XUV) radiation produced during the peak of the active phase of Sgr A*. We find that terrestrial planets could lose a total atmospheric mass comparable to that of present day Earth even at large distances (~1 kiloparsec) from the galactic center. Furthermore, we find that the direct biological damage caused by Sgr A* to surface life on planets not properly screened by an atmosphere was probably significant during the AGN phase, possibly hindering the development of complex life within a few kiloparsecs from the galactic center.
The small, inner moons of Saturn have intriguing shapes resembling in some cases ravioli and spaetzle. Just how they came to resemble giant pieces of pasta has been a mystery, but new computer simulations show they likely formed when smaller moons collided in the extreme tidal environment close to the ringed planet.It all started when Martin Rubin, an astrophysicist at the University of Bern, saw closeup pictures of Saturn’s moons Atlas and Pan that were taken by the Cassini orbiter in 2017. They featured large ridges and central bulges that gave them the appearance of huge flying saucers.
The team, from the University of Cambridge and the Instituto de Astrofísica de Canarias (IAC) in Spain, used the Gran Telescopio Canarias (GTC) to observe WASP-127b, a giant gaseous planet with partly clear skies and strong signatures of metals in its atmosphere. The results have been accepted for publication in the journal Astronomy & Astrophysics.WASP-127b has a radius 1.4 times larger than Jupiter but has only 20% of its mass. Such a planet has no analogue in our solar system and is rare even within the thousands of exoplanets discovered to date. It takes just over four days to orbit its parent star and its surface temperature is around 1400 K (1127° C).The observations of WASP-127b reveal the presence of a large concentration of alkali metals in its atmosphere, allowing simultaneous detections of sodium, potassium and lithium for the first time in an exoplanet. The sodium and potassium absorptions are very broad, which is characteristic of relatively clear atmospheres. According to modelling work done by the researchers, the skies of WASP-127b are approximately 50% clear.
In a May 31 statement, NASA said it has instructed the four teams studying proposed missions for consideration by the 2020 decadal survey to “narrow the scope” of their concepts so that their total cost is between $3 billion and $5 billion. That new cap, the statement said, reflected “current and anticipated budget constraints” for the agency’s astrophysics programs.
At least one of the four mission studies, though, claims to be exempt from this new directive. The Large UV/Optical/IR Surveyor (LUVOIR) mission would develop a space telescope with a primary mirror up to 15 meters in diameter, intended to support a broad range of astronomical research in ultraviolet through infrared wavelengths.[…] In a statement posted to its website, the LUVOIR team acknowledged that it and the other study teams received instructions from NASA Headquarters “to produce versions of their concepts that fit into the $3-5B cost box.” However, it added, “LUVOIR was exempt from this instruction.” It didn’t explain why and how it was granted an exemption.
"The discovery of asteroid 2018 LA is only the third time that an asteroid has been discovered to be on an impact trajectory, said Paul Chodas, manager of the Center for Near-Earth Object Studies (CNEOS) at JPL. "It is also only the second time that the high probability of an impact was predicted well ahead of the event itself."
Globular clusters could be up to 4 billion years younger than previously thought, new research led by the University of Warwick has found
This source, known as GW170817/GRB, has been the target of many follow-up surveys since it was believed that the merge could have led to the formation of a black hole. According to a new study by a team that analyzed data from NASA’s Chandra X-ray Observatory since the event, scientists can now say with greater confidence that the merger created a new black hole in our galaxy.The study, titled “GW170817 Most Likely Made a Black Hole“, recently appeared in The Astrophysical Journal Letters. The study was led by David Pooley, an assistant professor in physics and astronomy at Trinity University, San Antonio, and included members from the University of Texas at Austin, the University of California, Berkeley, and Nazarbayev University’s Energetic Cosmos Laboratory in Kazakhstan.
Caltech scientists have found, for the first time, that merging pairs of neutron stars—the burnt-out cores of stars that have exploded—create the majority of heavy elements in small "dwarf" galaxies. Heavy elements, such as silver and gold, are key for planet formation and even life itself. By studying these dwarf galaxies, the researchers hope to learn more about the primary sources of heavy elements for the whole universe.
Alpha Centauri A may be even less deadly than the sun—if there are any planets there.
It may have been one giant leap for man, but those steps may have consequences for mankind.The presence of astronauts on the moon caused an unexpected warming of its subsurface temperatures for a period of time in the 1970s, a new study has found after delving into "lost" tapes from the Apollo missions.
Within 30,000 years of impact, Mexico’s Chicxulub crater fostered a thriving ecosystem - a much faster recovery than many sites around the world.
WEST LAFAYETTE, Ind. — The climate throughout Mars’ early history has long been debated – was the Red Planet warm and wet, or cold and icy? New research published in Icarus provides evidence for the latter.
Some of the tiniest diamonds in the universe – bits of crystalline carbon hundreds of thousands of times smaller than a grain of sand – have been detected swirling around three infant star systems in the Milky Way. These microscopic gemstones are neither rare nor precious; they are, however, exciting for astronomers who identified them as the source of a mysterious cosmic microwave “glow” emanating from several protoplanetary disks in our galaxy.