Astronomija - opšta tema

[urkozamanje]

Aha, ja sam kapirao da ima veze najvise sa strukturom gasova zemljine atmosfere, azot, kiseonik itd.

[bigvlada]

Још мало да зумирају па ће да се виде бродови како горе...

 

Progress.

What is it?

Out here, progress is numbers.

Millimeters, kilometers, headcounts, death tolls.

This is progress.

Colonies burned, ships destroyed, people killed, money earned.

It all comes at a price.

And, if the price is right, I'll set the universe on fire.

[bigvlada]

Sid Mejer je bio u pravu, izgleda da je pronađen kandidat za cilj generacijskog međuzvezdanog broda. 

 

 

Signs of planet detected around sun’s nearest neighbor star

Proxima Centauri companion orbits in habitable zone

BY 

CHRISTOPHER CROCKETT

1:00PM, AUGUST 24, 2016

A WORLD NEXT DOOR  Proxima Centauri casts a reddish glow over the surface of Proxima b (illustrated), the closest exoplanet to Earth, while two companion stars, Alpha Centauri A and B, appear as bright pinpricks of light.

M. KORNMESSER/ESO

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Earth might have a kindred planet orbiting the star next door. A world at least 1.3 times as massive as Earth appears to orbit the closest star to the sun: Proxima Centauri, a dim red orb about 4.2 light-years away.

Dubbed Proxima b, the planet is cozied up to its star, needing just 11.2 days to complete one orbit. But despite the proximity to its star — just 5 percent of the distance from Earth to the sun — Proxima b is potentially habitable. Its temperature is just right for liquid water to flow on its surface, Guillem Anglada-Escudé, an astronomer at Queen Mary University of London, and colleagues report in the August 25Nature. That makes Proxima b the closest known world outside our solar system where life might exist.

“It’s an incredible discovery — it’s almost a gift,” says David Kipping, an astronomer at the Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass. With Proxima b, researchers might now have their best chance at characterizing the atmosphere of an Earthlike world in another solar system and probing for hints of life elsewhere in the galaxy.

 

Going the distance

 

DIGITIZED SKY SURVEY 2 (ACKNOWLEDGMENT: DAVIDE DE MARTIN, MAHDI ZAMANI), C. CROCKETT

 

Proxima Centauri is part of a triple star system (above, shown to scale) just over four light-years from the sun. Its two companions, Alpha Centauri AB, lie about 0.24 light-years from their dim neighbor.

 

Proxima Centauri, which lies in the southern constellation Centaurus, is a runt of a star. Temperatures at the surface run about 2,800 degrees Celsius cooler than our sun, giving Proxima a feeble, ruddy glow. The star is much closer in size to Jupiter than the sun, and even though it’s relatively close to Earth, Proxima is invisible to the naked eye — it wasn’t discovered until 1915. Part of a triple star system known as Alpha Centauri, it’s not clear whether Proxima is gravitationally bound to its brighter companions (taking hundreds of thousands of years to complete one orbit around both) or just passing by.

The Alpha Centauri system is no stranger to claims of exoplanets. In 2012, astronomers reported in Nature that the star Alpha Centauri B hosts a planet roughly as massive as Earth, though too warm to be habitable (SN: 11/3/12, p. 5). Other researchers are skeptical; a 2015 report in Monthly Notices of the Royal Astronomical Society Letters, for example, found no evidence for the planet. The claim for Proxima b appears to be much stronger.

Anglada-Escudé and colleagues found their quarry by looking for a minute wobble in the speed of Proxima Centauri, the sign of a gravitational tug from the orbiting planet. An intensive two-month observing campaign in early 2016 using two telescopes in Chile — the European Southern Observatory’s 3.6-meter and Very Large telescopes — confirmed earlier suspicions of a planet.

“It’s not clear if the planet will be Earthlike,” Anglada-Escudé says. Not much is known about Proxima b, such as its size or what its atmosphere is like. Even its mass is just a minimum estimate. Without knowing how the planet’s orbit is tilted relative to us, the researchers can say only that Proxima b is no lighter than 1.3 Earths — it could be heavier and have more in common with Neptune than Earth.

Even though it’s just one star away, “we will likely have to wait a long time in order to learn anything more about the planet,” says Heather Knutson, a planetary scientist at Caltech.

Telltale tug

 

G. ANGLADA-ESCUDÉ/ESO

 

Proxima Centauri’s speed relative to the sun oscillates by a few kilometers per hour, which indicates that a planet at least 1.3 times as massive as Earth is orbiting and tugging on the star. Red dots are measured velocities; the blue curve is a fit of orbital motion to the data.

The best bet, says Knutson, is to hope that the planet, when viewed from Earth, passes in front of Proxima Centauri, allowing starlight to filter through the planet’s atmosphere. Molecules in the atmosphere would betray their presence by absorbing specific wavelengths of light. Substances such as oxygen, methane and carbon dioxide are widely considered to be chemical markers of life.

If the planet does cross in front of the star, NASA’s James Webb Space Telescope, scheduled to launch in late 2018, should be able to characterize its atmosphere, says Mark Clampin, an astrophysicist at NASA’s Goddard Space Flight Center in Greenbelt, Md. Hundreds of hours of telescope time would need to be dedicated to the task. “It will be an extremely challenging observation, but not impossible,” he says.  

Scientists can also estimate the planet’s size by measuring how much light the planet blocks. The size combined with the mass would let researchers determine the density of Proxima b and figure out if the planet is puffy like Jupiter or rocky like Earth.

Kipping has already been monitoring Proxima Centauri with the Canadian MOST satellite, looking for a periodic dip in light caused by the planet partially blocking its sun. There’s only a 1.5 percent chance, however, that the planet lines up just-so with the star. And if it does line up, the inherent variability in Proxima Centauri’s light will make any drop in brightness from the planet hard to detect.     

Without a fortuitous alignment, “things get much more difficult,” Knutson says. Astronomers would have to rely on light coming from the planet — either an intrinsic infrared glow or visible light reflected from its sun. James Webb might be able to barely sense infrared light emanating from Proxima b, but it could be a decade or more before any other observatory is up to the challenge (SN: 4/30/16, p. 32). And even then, there are no guarantees. “It’s going to be very difficult to characterize the planet without sending a probe there,” Kipping says.

Breakthrough Starshot, a group funded by Russian entrepreneur Yuri Milner, wants to do just that. In April the group announced a plan to put $100 million toward developing technology that would send a fleet of nanocraft — robotic probes weighing just a few grams — toward Alpha Centauri, nudging them along with an Earth-based 100 gigawatt laser. Accelerating to roughly 20 percent the speed of light, the armada would arrive at Alpha Centauri about 20 years after launch. In comparison, the fastest spacecraft ever to leave Earth — the New Horizons mission to Pluto — would need roughly 90,000 years to complete the journey, traveling at its current speed of about 52,000 kilometers per hour.

“The discovery is likely to energize the project,” says Harvard University astrophysicist Avi Loeb, chairman of Breakthrough’s advisory committee. “A spacecraft equipped with a camera and various filters could take color images of the planet and infer whether it is green (harboring life as we know it), blue (with water oceans on its surface) or just brown (dry rock).”  

If anything is alive on Proxima b, it’s probably quite different from anything on Earth. Photosynthesizing organisms would have to deal with a faint, cool star that emits mostly infrared light. Proxima Centauri is also known for exuberant flares, which would buffet any orbiting planets with bursts of ultraviolet radiation and X-rays. “Conditions on such a planet would be very interesting for life,” says Lisa Kaltenegger, an astrophysicist at Cornell University.

 

IN THE ZONE The orbit of Proxima b, a planet with mild temperatures, is much smaller than Mercury’s (illustrated). Because Proxima Centauri is so cool, its habitable zone (green) cozies up to the star.

M. KORNMESSER, G. COLEMAN/ESO

 

Given such an alien environment, life might show its presence in unusual ways. Kaltenegger, along with Cornell astronomer Jack O'Malley-James, proposes looking for biofluorescence, a glow from organisms triggered by ultraviolet light, in the wake of stellar flares. Critters on Proxima b could have evolved biofluorescence as protection, taking harmful UV radiation and transforming it into more palatable visible light — a flicker that might be detectable from an Earth-based telescope. “The idea that we could spot a glow seems to be right out of a [science fiction] novel,” says Kaltenegger, whose proposal is expected to appear online August 24 on arXiv.org.

That’s assuming anything could survive on the planet. If Earth were placed in the same orbit as Proxima b, it would be stripped of its protective ozone roughly three times per Earth year, Kipping says. “That’s kind of bad,” he says. That rate doesn’t give the atmosphere time to recover, “but it’s not a showstopper,” he adds. A strong planetary magnetic field or a dense atmosphere might be able to withstand the blows. And if life has taken shelter underground or underwater — or is impervious to a lack of oxygen — it might still survive.

Whether or not critters crawl on Proxima b, the discovery of the planet “could really usher new energy into the search for other nearby worlds,” says Margaret Turnbull, an astronomer with the SETI Institute and based in Madison, Wis. Most exoplanets are hundreds to thousands of light-years away. But little is known about the possible planet families huddled up to the stars nearest to us. “I’d love to see interstellar travel,” says Turnbull. “To really inspire that kind of effort, we need interesting destinations like this.”

 

http://www.youtube.com/watch?v=FceRASaT9DM&feature=youtu.be

 

https://www.sciencenews.org/article/planet-detected-nearest-neighbor-star-proxima-centauri

 

Vreme je da se Orion izvadi iz naftalina ili da se požuri sa fuzijom, sada imamo gde da idemo.   

[bigvlada]

Planet found in habitable zone around nearest star

 

Pale Red Dot campaign reveals Earth-mass world in orbit around Proxima Centauri

 

Date: August 24, 2016

 

Source: European Southern Observatory (ESO)

 

Summary: Astronomers have found clear evidence of a planet orbiting the closest star to Earth, Proxima Centauri. The long-sought world, designated Proxima b, orbits its cool red parent star every 11 days and has a temperature suitable for liquid water to exist on its surface. This rocky world is a little more massive than the Earth and is the closest exoplanet to us -- and it may also be the closest possible abode for life outside the Solar System.

 

This artist's impression shows a view of the surface of the planet Proxima b orbiting the red dwarf star Proxima Centauri, the closest star to the Solar System. The double star Alpha Centauri AB also appears in the image to the upper-right of Proxima itself. Proxima b is a little more massive than the Earth and orbits in the habitable zone around Proxima Centauri, where the temperature is suitable for liquid water to exist on its surface.

Credit: ESO/M. Kornmesser

 

 

Astronomers using ESO telescopes and other facilities have found clear evidence of a planet orbiting the closest star to Earth, Proxima Centauri. The long-sought world, designated Proxima b, orbits its cool red parent star every 11 days and has a temperature suitable for liquid water to exist on its surface. This rocky world is a little more massive than the Earth and is the closest exoplanet to us -- and it may also be the closest possible abode for life outside the Solar System. A paper describing this milestone finding will be published in the journal Nature on 25 August 2016.

Just over four light-years from the Solar System lies a red dwarf star that has been named Proxima Centauri as it is the closest star to Earth apart from the Sun. This cool star in the constellation of Centaurus is too faint to be seen with the unaided eye and lies near to the much brighter pair of stars known as Alpha Centauri AB.

During the first half of 2016 Proxima Centauri was regularly observed with the HARPS spectrograph on the ESO 3.6-metre telescope at La Silla in Chile and simultaneously monitored by other telescopes around the world [1]. This was the Pale Red Dot campaign, in which a team of astronomers led by Guillem Anglada-Escudé, from Queen Mary University of London, was looking for the tiny back and forth wobble of the star that would be caused by the gravitational pull of a possible orbiting planet [2].

As this was a topic with very wide public interest, the progress of the campaign between mid-January and April 2016 was shared publicly as it happened on the Pale Red Dot website and via social media. The reports were accompanied by numerous outreach articles written by specialists around the world.

Guillem Anglada-Escudé explains the background to this unique search: "The first hints of a possible planet were spotted back in 2013, but the detection was not convincing. Since then we have worked hard to get further observations off the ground with help from ESO and others. The recent Pale Red Dot campaign has been about two years in the planning."

The Pale Red Dot data, when combined with earlier observations made at ESO observatories and elsewhere, revealed the clear signal of a truly exciting result. At times Proxima Centauri is approaching Earth at about 5 kilometres per hour -- normal human walking pace -- and at times receding at the same speed. This regular pattern of changing radial velocities repeats with a period of 11.2 days. Careful analysis of the resulting tiny Doppler shifts showed that they indicated the presence of a planet with a mass at least 1.3 times that of the Earth, orbiting about 7 million kilometres from Proxima Centauri -- only 5% of the Earth-Sun distance [3].

Guillem Anglada-Escudé comments on the excitement of the last few months: "I kept checking the consistency of the signal every single day during the 60 nights of the Pale Red Dot campaign. The first 10 were promising, the first 20 were consistent with expectations, and at 30 days the result was pretty much definitive, so we started drafting the paper!"

Red dwarfs like Proxima Centauri are active stars and can vary in ways that would mimic the presence of a planet. To exclude this possibility the team also monitored the changing brightness of the star very carefully during the campaign using the ASH2 telescope at the San Pedro de Atacama Celestial Explorations Observatory in Chile and the Las Cumbres Observatory telescope network. Radial velocity data taken when the star was flaring were excluded from the final analysis.

Although Proxima b orbits much closer to its star than Mercury does to the Sun in the Solar System, the star itself is far fainter than the Sun. As a result Proxima b lies well within the habitable zone around the star and has an estimated surface temperature that would allow the presence of liquid water. Despite the temperate orbit of Proxima b, the conditions on the surface may be strongly affected by the ultraviolet and X-ray flares from the star -- far more intense than the Earth experiences from the Sun [4].

Two separate papers discuss the habitability of Proxima b and its climate. They find that the existence of liquid water on the planet today cannot be ruled out and, in such case, it may be present over the surface of the planet only in the sunniest regions, either in an area in the hemisphere of the planet facing the star (synchronous rotation) or in a tropical belt (3:2 resonance rotation). Proxima b's rotation, the strong radiation from its star and the formation history of the planet makes its climate quite different from that of the Earth, and it is unlikely that Proxima b has seasons.

This discovery will be the beginning of extensive further observations, both with current instruments [5] and with the next generation of giant telescopes such as the European Extremely Large Telescope (E-ELT). Proxima b will be a prime target for the hunt for evidence of life elsewhere in the Universe. Indeed, the Alpha Centauri system is also the target of humankind's first attempt to travel to another star system, the StarShot project.

Guillem Anglada-Escudé concludes: "Many exoplanets have been found and many more will be found, but searching for the closest potential Earth-analogue and succeeding has been the experience of a lifetime for all of us. Many people's stories and efforts have converged on this discovery. The result is also a tribute to all of them. The search for life on Proxima b comes next..."

Notes

[1] Besides data from the recent Pale Red Dot campaign, the paper incorporates contributions from scientists who have been observing Proxima Centauri for many years. These include members of the original UVES/ESO M-dwarf programme (Martin Kürster and Michael Endl), and exoplanet search pioneers such as R. Paul Butler. Public observations from the HARPS/Geneva team obtained over many years were also included.

[2] The name Pale Red Dot reflects Carl Sagan's famous reference to the Earth as a pale blue dot. As Proxima Centauri is a red dwarf star it will bathe its orbiting planet in a pale red glow.

[3] The detection reported today has been technically possible for the last 10 years. In fact, signals with smaller amplitudes have been detected previously. However, stars are not smooth balls of gas and Proxima Centauri is an active star. The robust detection of Proxima b has only been possible after reaching a detailed understanding of how the star changes on timescales from minutes to a decade, and monitoring its brightness with photometric telescopes.

[4] The actual suitability of this kind of planet to support water and Earth-like life is a matter of intense but mostly theoretical debate. Major concerns that count against the presence of life are related to the closeness of the star. For example gravitational forces probably lock the same side of the planet in perpetual daylight, while the other side is in perpetual night. The planet's atmosphere might also slowly be evaporating or have more complex chemistry than Earth's due to stronger ultraviolet and X-ray radiation, especially during the first billion years of the star's life. However, none of the arguments has been proven conclusively and they are unlikely to be settled without direct observational evidence and characterisation of the planet's atmosphere. Similar factors apply to the planets recently found around TRAPPIST-1.

[5] Some methods to study a planet's atmosphere depend on it passing in front of its star and the starlight passing through the atmosphere on its way to Earth. Currently there is no evidence that Proxima b transits across the disc of its parent star, and the chances of this happening seem small, but further observations to check this possibility are in progress.

More information

This research is presented in a paper entitled "A terrestrial planet candidate in a temperate orbit around Proxima Centauri," by G. Anglada-Escudé et al., to appear in the journal Nature on 25 August 2016.

Story Source:

The above post is reprinted from materials provided by European Southern Observatory (ESO). Note: Content may be edited for style and length.

Journal Reference:

1. G. Anglada-Escudé et al. A terrestrial planet candidate in a temperate orbit around Proxima Centauri. Nature, 2016; DOI:10.1038/nature19106

 

https://www.sciencedaily.com/releases/2016/08/160824130453.htm

 

http://www.youtube.com/watch?v=bOc1qR8guSg

 

Krenite da crtate...  :D

 

 

 

žurka počinje.  :D

 

Edited August 26, 2016 by bigvlada

[Zis]

Trisolaris jebote 

 

http://www.parapsihopatologija.com/forums/index.php?showtopic=8905&p=3407253

[bigvlada]

Scientists discover a ‘dark’ Milky Way

 

 

Date:August 26, 2016

 

Source:Yale University

 

Summary:Using the world's most powerful telescopes, an international team of astronomers has found a massive galaxy that consists almost entirely of dark matter.

 

The dark galaxy Dragonfly 44. The image on the left is from the Sloan Digital Sky Survey. Only a faint smudge is visible. The image on the right is a long exposure with the Gemini telescope, revealing a large, elongated object. Dragonfly 44 is very faint for its mass and consists almost entirely of dark matter.

Credit: Images by Pieter van Dokkum, Roberto Abraham, Gemini, Sloan Digital Sky Survey

 

 

Using the world's most powerful telescopes, an international team of astronomers has found a massive galaxy that consists almost entirely of dark matter.

The galaxy, Dragonfly 44, is located in the nearby Coma constellation and had been overlooked until last year because of its unusual composition: It is a diffuse "blob" about the size of the Milky Way, but with far fewer stars.

"Very soon after its discovery, we realized this galaxy had to be more than meets the eye. It has so few stars that it would quickly be ripped apart unless something was holding it together," said Yale University astronomer Pieter van Dokkum, lead author of a paper in the Astrophysical Journal Letters.

Van Dokkum's team was able to get a good look at Dragonfly 44 thanks to the W.M. Keck Observatory and the Gemini North telescope, both in Hawaii. Astronomers used observations from Keck, taken over six nights, to measure the velocities of stars in the galaxy. They used the 8-meter Gemini North telescope to reveal a halo of spherical clusters of stars around the galaxy's core, similar to the halo that surrounds our Milky Way galaxy.

Star velocities are an indication of the galaxy's mass, the researchers noted. The faster the stars move, the more mass its galaxy will have.

"Amazingly, the stars move at velocities that are far greater than expected for such a dim galaxy. It means that Dragonfly 44 has a huge amount of unseen mass," said co-author Roberto Abraham of the University of Toronto.

Scientists initially spotted Dragonfly 44 with the Dragonfly Telephoto Array, a telescope invented and built by van Dokkum and Abraham.

Dragonfly 44's mass is estimated to be 1 trillion times the mass of the Sun, or 2 tredecillion kilograms (a 2 followed by 42 zeros), which is similar to the mass of the Milky Way. However, only one-hundredth of 1% of that is in the form of stars and "normal" matter. The other 99.99% is in the form of dark matter -- a hypothesized material that remains unseen but may make up more than 90% of the universe.

The researchers note that finding a galaxy composed mainly of dark matter is not new; ultra-faint dwarf galaxies have similar compositions. But those galaxies were roughly 10,000 times less massive than Dragonfly 44.

"We have no idea how galaxies like Dragonfly 44 could have formed," said Abraham. "The Gemini data show that a relatively large fraction of the stars is in the form of very compact clusters, and that is probably an important clue. But at the moment we're just guessing."

Van Dokkum, the Sol Goldman Family Professor of Astronomy and Physics at Yale, added: "Ultimately what we really want to learn is what dark matter is. The race is on to find massive dark galaxies that are even closer to us than Dragonfly 44, so we can look for feeble signals that may reveal a dark matter particle."

Additional co-authors are Shany Danieli, Allison Merritt, and Lamiya Mowla of Yale, Jean Brodie of the University of California Observatories, Charlie Conroy of Harvard, Aaron Romanowsky of San Jose State University, and Jielai Zhang of the University of Toronto.

Story Source:

The above post is reprinted from materials provided by Yale University. The original item was written by Jim Shelton. Note: Content may be edited for style and length.

Journal Reference:

1. Pieter van Dokkum, Roberto Abraham, Jean Brodie, Charlie Conroy, Shany Danieli, Allison Merritt, Lamiya Mowla, Aaron Romanowsky, Jielai Zhang. A HIGH STELLAR VELOCITY DISPERSION AND ∼100 GLOBULAR CLUSTERS FOR THE ULTRA-DIFFUSE GALAXY DRAGONFLY 44. The Astrophysical Journal, 2016; 828 (1): L6 DOI:10.3847/2041-8205/828/1/L6

 

 

Baš ih krenulo ovog meseca. :D

[Skyhighatrist]

Juno kreće da nas puni fotkama:

 

 

As NASA's Juno spacecraft closed in on Jupiter for its Aug. 27, 2016 pass, its view grew sharper and fine details in the north polar region became increasingly visible.

The JunoCam instrument obtained this view on August 27, about two hours before closest approach, when the spacecraft was 120,000 miles (195,000 kilometers) away from the giant planet (i.e., for Jupiter's center).

Unlike the equatorial region's familiar structure of belts and zones, the poles are mottled with rotating storms of various sizes, similar to giant versions of terrestrial hurricanes. Jupiter's poles have not been seen from this perspective since the Pioneer 11 spacecraft flew by the planet in 1974.

 

This infrared image gives an unprecedented view of the southern aurora of Jupiter, as captured by NASA's Juno spacecraft on August 27, 2016.

The planet's southern aurora can hardly be seen from Earth due to our home planet's position in respect to Jupiter's south pole. Juno's unique polar orbit provides the first opportunity to observe this region of the gas-giant planet in detail.

Juno's Jovian Infrared Auroral Mapper (JIRAM) camera acquired the view at wavelengths ranging from 3.3 to 3.6 microns -- the wavelengths of light emitted by excited hydrogen ions in the polar regions. The view is a mosaic of three images taken just minutes apart from each other, about four hours after the perijove pass while the spacecraft was moving away from Jupiter.

 

 

A gde ima puno fotki, tu se skuca i filmić:

 

[Skyhighatrist]

[bigvlada]

Otkriće II će imati gde da se okupa. :)

 

Sept. 26, 2016

RELEASE 16-096

 

 

 

NASA’s Hubble Spots Possible Water Plumes Erupting on Jupiter's Moon Europa

This composite image shows suspected plumes of water vapor erupting at the 7 o’clock position off the limb of Jupiter’s moon Europa. The plumes, photographed by NASA’s Hubble’s Space Telescope Imaging Spectrograph, were seen in silhouette as the moon passed in front of Jupiter. Hubble’s ultraviolet sensitivity allowed for the features -- rising over 100 miles (160 kilometers) above Europa’s icy surface -- to be discerned. The water is believed to come from a subsurface ocean on Europa. The Hubble data were taken on January 26, 2014. The image of Europa, superimposed on the Hubble data, is assembled from data from the Galileo and Voyager missions.

Credits: NASA/ESA/W. Sparks (STScI)/USGS Astrogeology Science Center

 

Astronomers using NASA's Hubble Space Telescope have imaged what may be water vapor plumes erupting off the surface of Jupiter's moon Europa. This finding bolsters other Hubble observations suggesting the icy moon erupts with high altitude water vapor plumes.

The observation increases the possibility that missions to Europa may be able to sample Europa’s ocean without having to drill through miles of ice.

“Europa’s ocean is considered to be one of the most promising places that could potentially harbor life in the solar system,” said Geoff Yoder, acting associate administrator for NASA’s Science Mission Directorate in Washington. “These plumes, if they do indeed exist, may provide another way to sample Europa’s subsurface.”

The plumes are estimated to rise about 125 miles (200 kilometers) before, presumably, raining material back down onto Europa's surface. Europa has a huge global ocean containing twice as much water as Earth’s oceans, but it is protected by a layer of extremely cold and hard ice of unknown thickness. The plumes provide a tantalizing opportunity to gather samples originating from under the surface without having to land or drill through the ice.

The team, led by William Sparks of the Space Telescope Science Institute (STScI) in Baltimore observed these finger-like projections while viewing Europa's limb as the moon passed in front of Jupiter.

The original goal of the team's observing proposal was to determine whether Europa has a thin, extended atmosphere, or exosphere. Using the same observing method that detects atmospheres around planets orbiting other stars, the team realized if there was water vapor venting from Europa’s surface, this observation would be an excellent way to see it.

"The atmosphere of an extrasolar planet blocks some of the starlight that is behind it," Sparks explained. "If there is a thin atmosphere around Europa, it has the potential to block some of the light of Jupiter, and we could see it as a silhouette. And so we were looking for absorption features around the limb of Europa as it transited the smooth face of Jupiter."

In 10 separate occurrences spanning 15 months, the team observed Europa passing in front of Jupiter. They saw what could be plumes erupting on three of these occasions.

This work provides supporting evidence for water plumes on Europa. In 2012, a team led by Lorenz Roth of the Southwest Research Institute in San Antonio, detected evidence of water vapor erupting from the frigid south polar region of Europa and reaching more than 100 miles (160 kilometers) into space. Although both teams used Hubble's Space Telescope Imaging Spectrograph instrument, each used a totally independent method to arrive at the same conclusion.

"When we calculate in a completely different way the amount of material that would be needed to create these absorption features, it's pretty similar to what Roth and his team found," Sparks said. "The estimates for the mass are similar, the estimates for the height of the plumes are similar. The latitude of two of the plume candidates we see corresponds to their earlier work."

But as of yet, the two teams have not simultaneously detected the plumes using their independent techniques. Observations thus far have suggested the plumes could be highly variable, meaning that they may sporadically erupt for some time and then die down. For example, observations by Roth’s team within a week of one of the detections by Sparks’ team failed to detect any plumes.

If confirmed, Europa would be the second moon in the solar system known to have water vapor plumes. In 2005, NASA's Cassini orbiter detected jets of water vapor and dust spewing off the surface of Saturn's moon Enceladus.

Scientists may use the infrared vision of NASA’s James Webb Space Telescope, which is scheduled to launch in 2018, to confirm venting or plume activity on Europa. NASA also is formulating a mission to Europa with a payload that could confirm the presence of plumes and study them from close range during multiple flybys.

“Hubble’s unique capabilities enabled it to capture these plumes, once again demonstrating Hubble’s ability to make observations it was never designed to make,” said Paul Hertz, director of the Astrophysics Division at NASA Headquarters in Washington. “This observation opens up a world of possibilities, and we look forward to future missions -- such as the James Webb Space Telescope -- to follow up on this exciting discovery.”

The work by Sparks and his colleagues will be published in the Sept. 29 issue of the Astrophysical Journal.

The Hubble Space Telescope is a project of international cooperation between NASA and ESA (the European Space Agency.) NASA's Goddard Space Flight Center in Greenbelt, Maryland, manages the telescope. STScI, which is operated for NASA by the Association of Universities for Research in Astronomy in Washington, conducts Hubble science operations.

http://www.nasa.gov/press-release/nasa-s-hubble-spots-possible-water-plumes-erupting-on-jupiters-moon-europa

 

Ne moramo da bušimo, sastav okeana će moći da se prouči mnogo lakše nego što smo mislili. :) Termin evropske meduze bi mogao da dobije potpuno novo značenje. 

 

 

 

 

Znam da se nije kupao na Evropi. 

 

 

Edited September 27, 2016 by bigvlada

[bigvlada]

Aresibo je dobio drugara. :)

 

China starts up world’s largest single-dish radio telescope

Dish with reflector as large as 30 football pitches will listen for signs of intelligent life and is one of several ‘world-class’ projects

 

 The five-hundred-metre aperture spherical radio telescope (Fast) on its first day of operation in Pingtang. Photograph: STR/AFP/Getty Images

The world’s largest radio telescope has begun operating in south-western China, a project Beijing says will help humanity search for alien life.

The five-hundred-metre aperture spherical radio telescope (acronym: Fast), nestled between hills in the mountainous region of Guizhou, began working about noon on Sunday, the official news agency, Xinhua, reported.

Built at a cost of 1.2bn yuan (£138m), the telescope dwarfs the Arecibo observatory in Puerto Rico to become the world’s largest single-dish radio telescope, with twice the sensitivity and a reflector as large as 30 football pitches.

Fast will use its vast dish, made up of 4,450 panels, to search for signs of intelligent life and to observe distant pulsars – tiny, rapidly spinning neutron stars believed to be the products of supernova explosions.China sees its ambitious, military-run, multi-billion-dollar space programme as symbolising the country’s progress. It plans a permanent orbiting space station by 2020 and eventually a manned mission to the moon. President Xi Jinping celebrated the launch, with reports on Sunday that he had sent a congratulatory letter to the scientists and engineers who contributed to its creation.

The telescope represents a leap forward for China’s astronomical capabilities and will be one of several “world-class” telescope projects launched in the next decade, said Yan Jun, head of China’s National Astronomical Observation (NAO), according to Xinhua.

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 The telescope’s visitor centre, which includes a planetarium. Photograph: Xinhua/Barcroft

In a test run before the launch, Fast had detected electromagnetic waves emitted by a pulsar more than 1,300 light years away.

Earlier, Xinhua cited Wu Xiangping, director-general of the Chinese Astronomical Society, as saying that the telescope’s high degree of sensitivity “will help us to search for intelligent life outside of the galaxy”.

Experts have been hunting for alien intelligence for six decades, pointing radio telescopes at stars in the hope of discovering signals from other civilisations, but have not yet found any evidence. Last month, a “strong signal” detected by a Russian telescope searching for extraterrestrial signals stirred interest among scientists, but experts said it was too early to make conclusions about its origin.The new Fast telescope could “lead to discoveries beyond our wildest imagination,” Douglas Vakoch, president of METI, a group seeking to send messages to space in search of alien life, told Xinhua.

Construction of Fast began in 2011, and local officials relocated nearly 10,000 people living within three miles (5km) to create a quieter environment for monitoring. Mobile phones in the area must be powered off to maintain radio silence.

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 The last panel of the Fast telescope is installed in July. Photograph: China Daily/Reuters

In the past, China has relocated hundreds of thousands of people to make way for large infrastructure projects such as dams and canals.

The area surrounding the telescope is remote and relatively poor. State media said it was chosen because there are no major towns nearby.

The villagers will be compensated with cash or housing. The budget for relocation is 1.8bn yuan (£208m), it was reported; more than the cost of constructing the telescope. At the beginning of this month, reports said 600 apartments had been built so far with the funds.

China has poured money into big science and technology projects as it seeks to become a hi-tech leader, but despite some gains the country’s scientific output still lags behind.

 

 

https://www.theguardian.com/world/2016/sep/25/china-unveils-world-largest-single-dish-radio-telescope

[Skyhighatrist]

Ćao Rosetta

 

Rosetta is set to complete its historic mission in a controlled descent to the surface of its comet on 30 September, with the end of mission confirmation predicted to be within 20 minutes of 13:20 CEST.

 

At 08:00 GMT / 10:00 CEST the last commands will be uploaded to the spacecraft to fine-tune the spacecraft’s pointing, based on the Navigation Camera images taken shortly after the collision manoeuvre. It is at this stage that a refined time for Rosetta’s impact will be known: it is currently predicted at 10:40 GMT / 12:40 CEST (±20 minutes) at the comet but it is expected to be narrowed down to within ±2 minutes.

 

There will be a short transmission streamed via rosetta.esa.int, https://livestream.com/ESA/rosettagrandfinale and ESA's Facebook page confirming this information, and once known, we will update the time indicated at the top of this page and via our blog and social media channels.

 

Note that due to the signal travel time, the end of mission will be confirmed 40 minutes after the impact has actually occurred, within 20 minutes of 11:20 GMT / 13:20 CEST.

Live streaming will begin at 10:30 GMT / 12:30 CEST via rosetta.esa.int, https://livestream.com/ESA/rosettagrandfinale and ESA's Facebook page featuring status updates from mission controllers live from ESA’s European Space Operations Centre in Darmstadt, Germany. Note that the start time may be subject to ±20 minute change depending on the final confirmed impact time.

 

Edited September 30, 2016 by Skyhighatrist

[Gospodin Slucaj]

[Ayatollah]

Saga o KIC 8462852 se nastavlja. Nazalost (ili na srecu), izgleda da nema Dajsonove sfere.

 

Our galaxy’s weirdest star, KIC 8462852, is even weirder than previously thought, showing changes never observed before in a star like this.

To quickly recap, last year it was announced that the object experienced dramatic and rapid changes in brightness, which led to the wild speculation that the object was surrounded by an alien megastructure. New observations have shown that there are no aliens around it but the mystery has deepened further still, ashistorical data suggests that the star has inexplicably dimmed by 14 percent in just over a century.

Researchers Josh Simon and Ben Montet, using observations by NASA’s Kepler space telescope, discovered that KIC 8462852 faded slowly and then suddenly during the four years it was studied.

“Our highly accurate measurements over four years demonstrate that the star really is getting fainter with time,” said Montet, from Caltech, in a statement. "It is unprecedented for this type of star to slowly fade for years, and we don’t see anything else like it in the Kepler data.”

A pre-print of the research was released in August, and is now published in the Astrophysical Journal. In it, the scientists compared KIC 8462852 to 500 similar stars also observed by Kepler. Although they saw a small fraction getting fainter with time, none had dimming episodes as intense.

KIC 8462852, which is also known as Tabby’s star, faded about 1 percent in the first three years of the study, before suddenly dropping another 2 percent more. It then remained stable for the final six months.

“This star was already completely unique because of its sporadic dimming episodes. But now we see that it has other features that are just as strange, both slowly dimming for almost three years and then suddenly getting fainter much more rapidly,” Simon, from the Carnegie Institute of Science, continued.

The six months of dimming in 2012 could be explained by the breakup of a planet or comets, but the apparent long term fading must be something else. And we still don’t know what caused a dramatic change in brightness reported last year.

“It’s a big challenge to come up with a good explanation for a star doing three different things that have never been seen before,” Montet added. “But these observations will provide an important clue to solving the mystery of KIC 8462852.”

 

[Malvo]

Ukratko, nove opservacije kazu da nisu sigurni o cemu se radi :D

[Ayatollah]

Ukratko, nove opservacije kazu da nisu sigurni o cemu se radi :D

 

Mogao bih da je pronađem u Elite:Dangerous (ako su je uneli), pa da odem i da vidim o čemu se radi. Doduše moram prvo da kupim Fuel Scoop, i onaj self-repairing sistem (tj. dva takva sistema, jer ne može popraviti samog sebe)  :D