Saturday, April 9, 2016

A Star With A Disk Of Water Ice? Meet HD 100546

A Star With A Disk Of Water Ice? Meet HD 100546:



Young stars have a disk of gas and dust around them called a protoplanetary disk. Out of this disk planets are formed, and the presence of water ice in the disc affects where different types of planets form. Credit: NASA/JPL-Caltech


It might seem incongruous to find water ice in the disk of gas and dust surrounding a star. Fire and ice just don't mix. We would never find ice near our Sun.But our Sun is old. About 5 billion years old, with about 5 billion more to go. Some younger stars, of a type called Herbig Ae/Be stars (after American astronomer George Herbig,) are so young that they are surrounded by a circumstellar disk of gas and dust which hasn't been used up by the formation of planets yet. For these types of stars, the presence of water ice is not necessarily unexpected.Water ice plays an important role in a young solar system. Astronomers think that water ice helps large, gaseous, planets to form. The presence of ice makes the outer section of a planetary disk more dense. This increased density allows the cores of gas planets to coalesce and form.Young solar systems have what is called a snowline. It is the boundary between terrestrial and gaseous planets. Beyond this snowline, ice in the protoplanetary disk encourages gas planets to form. Inside this snowline, the lack of water ice contributes to the formation of terrestrial planets. You can see this in our own Solar System, where the snowline must have been between Mars and Jupiter.A team of astronomers using the Gemini telescope observed the presence of water ice in the protoplanetary disk surrounding the star HD 100546, a Herbig Ae/Be star about 320 light years from us. At only 10 million years old, this star is rather young, and it is a well-studied star. The Hubble has found complex, spiral patterns in the disk, and so far these patterns are unexplained.HD 100546 is also notable because in 2013, research showed the probable ongoing formation of a planet in its disk. This presented a rare opportunity to study the early stages of planet formation. Finding ice in the disk, and discovering how deep it exists in the disk, is a key piece of information in understanding planet formation in young solar systems.Finding this ice took some clever astro-sleuthing. The Gemini telescope was used, with its Near-Infrared Coronagraphic Imager (NICI), a tool used to study gas giants. The team installed H2O ice filters to help zero in on the presence of water ice. The protoplanetary disk around young stars, as in the case of HD 100546, is a mixed up combination of dusts and gases, and isolating types of materials in the disk is not easy.Water ice has been found in disks around other Herbig Ae/Be stars, but the depth of distribution of that ice has not been easy to understand. This paper shows that the ice is present in the disk, but only shallowly, with UV photo desorption processes responsible for destroying water ice grains closer to the star.It may seem trite so say that more study is needed, as the authors of the study say. But really, in science, isn't more study always needed? Will we ever reach the end of understanding? Certainly not. And certainly not when it comes to the formation of planets, which is a pretty important thing to understand.

The post A Star With A Disk Of Water Ice? Meet HD 100546 appeared first on Universe Today.

NGC 6357: Cathedral to Massive Stars

NGC 6357: Cathedral to Massive Stars:

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2016 March 27


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NGC 6357: Cathedral to Massive Stars

Image Credit: NASA, ESA and Jesús Maíz Apellániz (IAA, Spain); Acknowledgement: Davide De Martin (ESA/Hubble)


Explanation: How massive can a normal star be? Estimates made from distance, brightness and standard solar models had given one star in the open cluster Pismis 24 over 200 times the mass of our Sun, making it one of the most massive stars known. This star is the brightest object located just above the gas front in the featured image. Close inspection of images taken with the Hubble Space Telescope, however, have shown that Pismis 24-1 derives its brilliant luminosity not from a single star but from three at least. Component stars would still remain near 100 solar masses, making them among the more massive stars currently on record. Toward the bottom of the image, stars are still forming in the associated emission nebula NGC 6357. Appearing perhaps like a Gothic cathedral, energetic stars near the center appear to be breaking out and illuminating a spectacular cocoon.

Tomorrow's picture: Orion Mountain



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Orions Belt and Sword over Teides Peak

Orions Belt and Sword over Teides Peak:

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2016 March 28


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Orion's Belt and Sword over Teide's Peak

Image Credit & Copyright: Cesar & Carlos Tejedor


Explanation: The southern part of Orion, the famous constellation and mythical hunter, appears quite picturesque posing here over a famous volcano. Located in the Canary Islands off the northwest coast of Africa, the snow-peaked Teide is one of the largest volcanoes on Earth. Lights from a group planning to summit Teide before dawn are visible below the volcano's peak. In this composite of exposures taken from the same location one night last month, the three iconic belt stars of Orion are seen just above the peak, while the famous Orion Nebula and the rest of Orion's sword are visible beyond the volcano's left slope. Also visible in the long duration sky image are the Horsehead Nebula, seen as a dark indentation on the red emission nebula to the belt's left, and the Flame Nebula, evident just above and to the right of the Horsehead.

Tomorrow's picture: rover, dune, mountain, mars



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NGC 6188 and NGC 6164

NGC 6188 and NGC 6164:

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2016 March 30


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NGC 6188 and NGC 6164

Image Credit & Copyright: Martin Pugh & Rick Stevenson


Explanation: Fantastic shapes lurk in clouds of glowing gas in the giant star forming region NGC 6188. The emission nebula is found about 4,000 light years away near the edge of a large molecular cloud unseen at visible wavelengths, in the southern constellation Ara. Massive, young stars of the embedded Ara OB1 association were formed in that region only a few million years ago, sculpting the dark shapes and powering the nebular glow with stellar winds and intense ultraviolet radiation. The recent star formation itself was likely triggered by winds and supernova explosions, from previous generations of massive stars, that swept up and compressed the molecular gas. Joining NGC 6188 on this cosmic canvas, visible toward the lower right, is rare emission nebula NGC 6164, also created by one of the region's massive O-type stars. Similar in appearance to many planetary nebulae, NGC 6164's striking, symmetric gaseous shroud and faint halo surround its bright central star near the bottom edge. The impressively wide field of view spans over 3 degrees (six full Moons), corresponding to over 200 light years at the estimated distance of NGC 6188. Three image sets have been included in the featured composite.

Tomorrow's picture: north and south



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Big Dipper to Southern Cross

Big Dipper to Southern Cross:

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2016 March 31


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Explanation: Welcome to an equatorial night. This remarkable 24 frame night skyscape was captured from Maba Beach on the Indonesian island of Halmahera during the evening of March 4. Seen from a mere 0.7 degrees northern latitude, both famous northern and southern asterisms and navigational aids lie within the panoramic view. The Big Dipper is on the far left and Southern Cross at the far right. Beyond the fading campfire on that night a yellow-orange celestial triangle is set by Mars, Antares, and Saturn. It stands above the rising central Milky Way, or "Miett" in the local Maba language. Of course, you can follow the pole pointing stars in the cup of the Big Dipper or body of the Southern Cross to the north and south celestial poles. Both lie just at the horizon in the view from the island's equatorial beach.

Europa: Discover Life Under the Ice

Europa: Discover Life Under the Ice:

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2016 April 1


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Explanation: Looking for an interplanetary vacation destination? Consider a visit to Europa, one of the Solar System's most tantalizing moons. Ice-covered Europa follows an elliptical path in its 85 hour orbit around our ruling gas giant Jupiter. Heat generated from strong tidal flexing by Jupiter's gravity keeps Europa's salty subsurface ocean liquid all year round. That also means even in the absence of sunlight Europa has energy that could support simple life forms. Unfortunately, it is currently not possible to make reservations at restaurants on Europa, where you might enjoy a dish of the local extreme shrimp. But you can always choose another destination from Visions of the Future.

Close up of the Bubble Nebula

Close up of the Bubble Nebula:

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2016 April 3


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Close-up of the Bubble Nebula

Image Credit: NASA, ESA, Hubble Legacy Archive; Processing & License: Judy Schmidt


Explanation: It's the bubble versus the cloud. NGC 7635, the Bubble Nebula, is being pushed out by the stellar wind of massive central star BD+602522. Next door, though, lives a giant molecular cloud, visible to the right. At this place in space, an irresistible force meets an immovable object in an interesting way. The cloud is able to contain the expansion of the bubble gas, but gets blasted by the hot radiation from the bubble's central star. The radiation heats up dense regions of the molecular cloud causing it to glow. The Bubble Nebula, featured here in scientifically mapped colors to bring up contrast, is about 10 light-years across and part of a much larger complex of stars and shells. The Bubble Nebula can be seen with a small telescope towards the constellation of the Queen of Aethiopia (Cassiopeia).

Astrophysicists: Browse 1,200+ codes in the Astrophysics Source Code Library

Tomorrow's picture: Seljarlandsfossian Rhapsody



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Lucid Dreaming

Lucid Dreaming:

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2016 April 4


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Lucid Dreaming

Image Credit & Copyright: Arnar Kristjansson; Rollover Annotation: Judy Schmidt


Explanation: Is this the real world? Or is it just fantasy? The truth started with a dream -- a dream that the spectacular Seljarlandsfoss waterfall in southern Iceland could be photographed with a backdrop of an aurora-filled sky. Soon after a promising space weather report, the visionary astrophotographer and his partner sprang into action. After arriving, capturing an image of the background sky, complete with a cool green aurora, turned out to be the easy part. The hard part was capturing the waterfall itself, for one reason because mist kept fogging the lens! Easy come, easy go -- it took about 100 times where someone had to go back to the camera -- on a cold night and over slippery rocks -- to see how the last exposure turned out, wipe the lens, and reset the camera for the next try. Later, the best images of land and sky were digitally combined. Visible in the sky, even well behind the aurora, are numerous stars of the northern sky. The resulting title -- given by the astrophotographer -- was influenced by a dream-like quality of the resulting image, possibly combined with the knowledge that some things really mattered in this effort to make a dream come true.

Tomorrow's picture: lava world



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Auroras and the Magnetosphere of Jupiter

Auroras and the Magnetosphere of Jupiter:

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2016 April 6


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Auroras and the Magnetosphere of Jupiter

Illustration Credit: JAXA; Inset Image Credit: NASA, ESA, Chandra, Hubble


Explanation: Jupiter has auroras. Like near the Earth, the magnetic field of our Solar System's largest planet compresses when impacted by a gust of charged particles from the Sun. This magnetic compression funnels charged particles towards Jupiter's poles and down into the atmosphere. There, electrons are temporarily excited or knocked away from atmospheric gases, after which, when de-exciting or recombining with atmospheric ions, auroral light is emitted. The featured illustration portrays the magnificent magnetosphere around Jupiter in action. In the inset image released last month, the Earth-orbiting Chandra X-ray Observatory shows unexpectedly powerful X-ray light emitted by Jovian auroras, depicted in false-colored purple. That Chandra inset is superposed over an optical image taken at a different time by the Hubble Space Telescope. This aurora on Jupiter was seen in October 2011, several days after the Sun emitted a powerful Coronal Mass Ejection (CME).

Tomorrow's picture: star hub



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Wolf-Lundmark-Melotte

Wolf-Lundmark-Melotte:

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2016 April 7


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Wolf-Lundmark-Melotte

Image Credit: ESO, VST/Omegacam Local Group Survey

Explanation: Named for the three astronomers instrumental in its discovery and identification, Wolf - Lundmark - Melotte (WLM) is a lonely dwarf galaxy. Seen toward the mostly southern constellation Cetus, about 3 million light-years from the Milky Way, it is one of the most remote members of our local galaxy group. In fact, it may never have interacted with any other local group galaxy. Still, telltale pinkish star forming regions and hot, young, bluish stars speckle the isolated island universe. Older, cool yellowish stars fade into the small galaxy's halo, extending about 8,000 light-years across. This sharp portrait of WLM was captured by the 268-megapixel OmegaCAM widefield imager and survey telescope at ESO's Paranal Observatory.

Tomorrow's picture: Lapland at Night



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Lapland Northern Lights

Lapland Northern Lights:

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2016 April 8


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Explanation: Early spring in the northern hemisphere is good season for aurora hunters. Near an equinox Earth's magnetic field is oriented to favor interactions with the solar wind that trigger the alluring glow of the northern lights. On March 28/29 the skies over Kaunispää Hill, Lapland, Finland did not disappoint. That night's expansive auroral curtains are captured in this striking panoramic view that covers a full 360 degrees. Local skywatchers were mesmerized by bright displays lasted throughout the dark hours, shimmering with colors easily visible to the naked eye.

Wednesday, April 6, 2016

Crop Circles Parte 1 - O que eles não querem que você veja?





Crop Circles- Decifrando o Mistério (Português)





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Após 15 minutos morto, acorda e fala sobre o falso messias para 2016





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Sunday, March 27, 2016

ROSE GALAXY

ROSE GALAXY

ROSE GALAXY
ROSE GALAXY

Saturday, March 26, 2016

Close Comet and the Milky Way

Close Comet and the Milky Way: APOD: 2016 March 25 - Close Comet and the Milky Way



Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.


2016 March 25


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Close Comet and the Milky Way
Image Credit & Copyright: Alex Cherney (Terrastro, TWAN)
Explanation: Comet 252P/Linear's lovely greenish coma is easy to spot in this expansive southern skyscape. Visible to the naked eye from the dark site near Flinders, Victoria, Australia, the comet appears tailless. Still, its surprisingly bright coma spans about 1 degree, posed here below the nebulae, stars, and dark rifts of the Milky Way. The five panels used in the wide-field mosaic were captured after moonset and before morning twilight on March 21. That was less than 24 hours from the comet's closest approach, a mere 5.3 million kilometers from our fair planet. Sweeping quickly across the sky because it is so close to Earth, the comet should be spotted in the coming days by northern hemisphere comet watchers. In predawn but moonlit skies it will move through Sagittarius and Scorpius seen toward the southern horizon. That's near the triangle formed by bright, yellowish, Mars, Saturn, and Antares at the upper left of this frame.

Tomorrow's picture: equinox^3

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Friday, March 25, 2016

Best NASA Images Yet Of Ceres’ Brightest Spot

Best NASA Images Yet Of Ceres’ Brightest Spot:



Ceres Occator color tight_FEA


Ah, dome sweet dome. Scientists from NASA's Dawn mission unveiled new images from the spacecraft's lowest orbit at Ceres, including highly anticipated views of Occator Crater, at the 47th annual Lunar and Planetary Science Conference in The Woodlands, Texas, on Tuesday. The new images, taken from Dawn's low-altitude mapping orbit (LAMO) of 240 miles (385 kilometers) above Ceres, reveal a dome in a smooth-walled pit in the bright center of the crater. Linear fractures crisscross the top and flanks of the dome with still more fractures slicing across the nearby plains."Before Dawn began its intensive observations of Ceres last year, Occator Crater looked to be one large bright area. Now, with the latest close views, we can see complex features that provide new mysteries to investigate," said Ralf Jaumann, planetary scientist and Dawn co-investigator at the German Aerospace Center (DLR) in Berlin. "The intricate geometry of the crater interior suggests geologic activity in the recent past, but we will need to complete detailed geologic mapping of the crater in order to test hypotheses for its formation."Like me, you've probably been anticipating LAMO for months, when we'd finally get our clearest view of the famous "bright spots". Spectral observations have shown that the patches are consistent with a magnesium sulfate called hexahydrite that resembles the more familiar Epsom salts here on Earth. Scientists think these salt-rich areas were residue left behind when water-ice sublimated in the past. Impacts from asteroids could have broken into Ceres' crust and possibly unearthed salt-rich ices. Exposed to the vacuum of space, the ice would have sublimated (vaporized), leaving the salt behind.The team also released an enhanced color map of the surface of Ceres that reveals a diversity of surface materials and how they relate to Ceres' landforms. The dwarf planet doesn't have as many large impact basins as scientists expected, but the number of smaller craters generally matches their predictions. The blue material highlighted in the color map is related to flows, smooth plains and mountains, which appear to be very young surface features."Although impact processes dominate the surface geology on Ceres, we have identified specific color variations on the surface indicating material alterations that are due to a complex interaction of the impact process and the subsurface composition," Jaumann said. "Additionally, this gives evidence for a subsurface layer enriched in ice and volatiles."We're learning more about that subsurface ice thanks to Dawn's Gamma Ray and Neutron Detector (GRaND). Neutrons and gamma rays produced by cosmic rays interacting with the topmost yard (meter) of the loose rock and dust called regolith provide a fingerprint of Ceres' chemical makeup. Lower counts indicate the presence of hydrogen, and since water's rich in hydrogen (H2o), the results from GRanD suggest concentrations of water ice in the near-surface at high latitudes."Our analyses will test a longstanding prediction that water ice can survive just beneath Ceres' cold, high-latitude surface for billions of years," said Tom Prettyman, the lead for GRaND and Dawn co-investigator at the Planetary Science Institute, Tucson, Arizona.Dawn scientists also reported that the Visual and Infrared Mapping Spectrometer (VIR) has detected water at Oxo Crater, a young, 6-mile-wide (9-kilometer-wide) feature in Ceres' northern hemisphere. This water could either be bound up in minerals or exist as ice and may have been exposed during a landslide or impact or a combination of the two events.  Oxo is the only place on Ceres where water has been detected at the surface so far.Not only have scientists found evidence of possible extensive subsurface ice, but the composition of the surface is variable. Using VIR, which measures mineral composition by how those minerals reflect sunlight, they found that Haulani Crater shows a different proportion of surface materials than its surroundings. While the surface of Ceres is mostly made of a mixture of materials containing carbonates and phyllosilicates (clays), their relative proportion varies across the surface."False-color images of Haulani show that material excavated by an impact is different than the general surface composition of Ceres. The diversity of materials implies either that there is a mixed layer underneath, or that the impact itself changed the properties of the materials," said Maria Cristina de Sanctis, the VIR instrument lead scientist.All these cool stuff we're finding out about this small body makes it nearly as exciting as Pluto. Taking a closer look is the best form of education.

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Solar Storms Ignite Aurora On Jupiter

Solar Storms Ignite Aurora On Jupiter:



Composite images from the Chandra X-Ray Observatory and the Hubble Space Telescope show the hyper-energetic x-ray auroras at Jupiter. The image on the left is of the auroras when the coronal mass ejection reached Jupiter, the image on the right is when the auroras subsided. The auroras were triggered by a coronal mass ejection from the Sun that reached the planet in 2011. Image: X-ray: NASA/CXC/UCL/W.Dunn et al, Optical: NASA/STScI


The Earthly Northern Lights are beautiful and astounding, but when it comes to planetary light shows, what happened at Jupiter in 2011 might take the cake. In 2011, a coronal mass ejection (CME) struck Jupiter, producing x-ray auroras 8 times brighter than normal, and hundreds of times more energetic than Earth's auroras. A paper in the March 22nd, 2016 issue of the Journal of Geophysical Research gave the details.The Sun emits a ceaseless stream of energetic particles called the solar wind. Sometimes, the Sun ramps up its output, and what is called a coronal mass ejection occurs. A coronal mass ejection is a massive burst of matter and electromagnetic radiation. Though they're slow compared to other phenomena arising from the Sun, such as solar flares, CMEs are extremely powerful.When the CME in 2011 reached Jupiter, NASA's Chandra X-Ray Observatory was watching, the first time that Jupiter's X-ray auroras were monitored at the same time that a CME arrived. Along with some very interesting images of the event, the team behind the study learned other things. The CME that struck Jupiter actually compressed that planet's magnetosphere. It forced the boundary between the solar wind and Jupiter's magnetic field in towards the planet by more than 1.6 million kilometers (1 million miles.)The scientists behind this study used the data from this event to not only pinpoint the source of the x-rays, but also to identify areas for follow-up investigation. They'll be using not only Chandra, but also the European Space Agency's XMM Newton observatory to collect data on Jupiter's magnetic field, magnetosphere, and aurora.NASA's Juno spacecraft will reach Jupiter this summer. One of its primary missions is to map Jupiter's magnetic fields, and to study the magnetosphere and auroras. Juno's results will be fascinating to anyone interested in Jupiter's auroras.Here at Universe Today we've written about Jupiter's aurora's here, coronal mass ejections here, and the Juno mission here.

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Most ‘Outrageous’ Luminous Galaxies Ever Observed

Most ‘Outrageous’ Luminous Galaxies Ever Observed:



An artist's conception of an extremely luminous infrared galaxy similar to the ones reported in this paper. Image credit: NASA/JPL-Caltech.


Astronomers might be running out of words when it comes to describing the brightness of objects in the Universe.Luminous, Super-Luminous, Ultra-Luminous, Hyper-Luminous. Those words have been used to describe the brightest objects we've found in the cosmos. But now astronomers at the University of Massachusetts Amherst have found galaxies so bright that new adjectives are needed. Kevin Harrington, student and lead author of the study describing these galaxies, says, "We’ve taken to calling them ‘outrageously luminous’ among ourselves, because there is no scientific term to apply.”The terms "ultra-luminous" and "hyper-luminous" have specific meanings in astronomy. An infrared galaxy is called “ultra-luminous” when it has a rating of about 1 trillion solar luminosities. At 10 trillion solar luminosities, the term "hyper-luminous" is used. For objects greater than that, at around 100 trillion solar luminosities, "we don't even have a name," says Harrington.The size and brightness of these 8 galaxies is astonishing, and their existence comes as a surprise. Professor Min Yun, who leads the team, says, "The galaxies we found were not predicted by theory to exist; they’re too big and too bright, so no one really looked for them before.” These newly discovered galaxies are thought to be about 10 billion years old, meaning they were formed about 4 billion years after the Big Bang. Their discovery will help astronomers understand the early Universe better.“Knowing that they really do exist and how much they have grown in the first 4 billion years since the Big Bang helps us estimate how much material was there for them to work with. Their existence teaches us about the process of collecting matter and of galaxy formation. They suggest that this process is more complex than many people thought,” said Yun.Gravitational lensing plays a role in all this though. The galaxies are not as large as they appear from Earth. As their light passes by massive objects on its way to Earth, their light is magnified. This makes them look 10 times brighter than they really are. But event taking gravitational lensing into account, these are still impressive objects.But it's not just the brightness of these objects that are significant. Gravitational lensing of a galaxy by another galaxy is rare. Finding 8 of them is unheard of, and could be "another potentially important discovery," says Yun. The paper highlights these galaxies as being among the most interesting objects for further study "because the magnifying property of lensing allows us to probe physical details of the intense star formation activities at sub-kpc scale..."The team's analysis also shows that the extreme brightness of these galaxies is caused solely by star formation.“The Milky Way produces a few solar masses of stars per year, and these objects look like they forming one star every hour,” Yun says. Harrington adds, “We still don’t know how many tens to hundreds of solar masses of gas can be converted into stars so efficiently in these objects, and studying these objects might help us to find out.”It took a tag team of telescopes to discover and confirm these outrageously luminous galaxies. The team of astronomers, led by Professor Min Yun, used the 50 meter diameter Large Millimeter Telescope for this work. It sits atop an extinct volcano in Mexico, the 15,000 foot Sierra Negra. They also relied on the Herschel Observatory, and the Planck Surveyor.

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