Archive for category Astronomy
A Wacky Distorted View of the Recent Solar Eclipse
Posted by Michael B. Calyn in Astronomy on May 14, 2013
A Wacky Distorted View of the Recent Solar Eclipse
by DAVID DICKINSON on MAY 13, 2013
A three image sequence of last Friday’s rising annular eclipse. Credit: Geoff Sims. (@beyond_beneath)
Just when we’d thought that we’ve seen every possible type of eclipse image, we’re happily surprised by the Universe.
If you’re like me, you watch the original Star Wars film and wonder what kind of eclipses could be seen from the surface of Tatooine. Maybe you even wonder what things would look like if an extra sun and moon were to be thrown into the mix. How often, if ever, would such a bizarre alignment sync up?
Astrophotographer Geoff Sims provided us with just such a bizarre view this past weekend.
Geoff was one of a handful of intrepid photographers that braved the wilds of the Australian Outback to deliver us some stunning views of last week’s rising annular eclipse. We wrote of how to observe this celestial wonder late last month on Universe Today, and documented the efforts of photographers, both Earthbound and otherwise, the day of the eclipse this past Friday.
For this amazing image, Geoff positioned himself along the track of annularity in the Great Sandy Desert in Western Australia. Even the name of the site, the Plutonic Gold Mine outside of Newman, Australia couldn’t be beat!
The series is a composite of three exposures which were taken about three minutes apart. Mr. Simms relates how he accomplished this unforgettable image on his Facebook page:
“The lower image shows a flattened and distorted Sun perched right on the horizon, just seconds before the annular eclipse began. The middle image shows the annular phase, while the upper image shows the Sun some minutes after annularity.”
Mr. Sims used a Canon Mark III DSLR camera with a 500mm lens shooting at 1/1,000thof a second exposures at a focal ratio of f/8 and an ISO setting of 100.
Amazingly, other photographers positioned very near the eclipse graze line caught sight of what are known as Bailey’s Beads as well. More commonly seen during a total solar eclipse, these are caused by sunlight streaming through ridges and valleys on the limb of the Moon. This can also cause the brilliant diamond ring effect seen during a total solar eclipse. In the case of an annular eclipse, this manifests as a ragged broken edge where the disk of the Sun meets the Moon:
Bailey’s Beads captured very briefly during last week’s annular eclipse. (Credit: Geoff Sims).
An annular eclipse occurs when the Moon eclipses the Sun near apogee, or its most distant point in its orbit and is hence visually too small to cover the Sun as seen from the Earth. A similar eclipse occurred over the Pacific and the western U.S. last year onMay 20th, leading to a series of “horned sunset” photos taken across Texas and New Mexico.
But what is the most astonishing aspect of the eclipse sequence is the extreme distortion occurring across the very bottom image sitting on the horizon. When you’re looking low to the horizon, you’re viewing objects through a thicker cross-section of the atmosphere. This is what is termed as a higher air mass, and most astro-imagers avoid it entirely, preferring to catch objects with as little distortion as possible as they transit across the local meridian. This distortion can be extreme enough to result inatmospheric refraction of rising and setting objects like the Sun, Moon or planets, causing them to appear moments before or after they actually rose or set over the local horizon. In the case of the bottom image, the lower limb of the solar annulus (the technical name for what folks call the “ring of fire” seen during an annular eclipse) is actually distorted enough to appear along the rim of the local horizon!
To our knowledge, such an extremely distorted eclipse has never been documented before. One also wonders if a “green flash” could be captured by a properly positioned observer on a mountaintop or out to sea during a sunset or sunrise annular or total solar eclipse.
2013 will offer one more chance to try. On November 3rd, a hybrid solar eclipse will race across the Atlantic Ocean and central Africa. This is an eclipse that is literally an annular across a portion of its track and a total across another. The eclipse will begin at sunrise just south of Bermuda and end at sunset in eastern Africa. The maximum period of totality is 1 minute and 40 seconds off of the coast of Liberia, and the southern regions of Ethiopia offer the best shot at a sunset eclipse. Tantalizingly, the Florida Space Coast will get a rising partial eclipse only a few percent in magnitude.
Kudos to Mr. Sims for providing us with an unforgettable view of this rare cosmic spectacle. Australia won’t see another total solar eclipse until July 22nd, 2028, and another purely annular eclipse won’t occur until April 29th, 2014 across a very small section of the Antarctic.
And next week, we’ll have a very shallow penumbral eclipse on May 25th, and event is so subtle that few if any will notice it. Still, it is from such humble beginnings that great things are made, as we witness the birth of a new lunar saros… stay tuned!
A Wacky Distorted View of the Recent Solar Eclipse.
Related articles
- A Wacky Distorted View of the Recent Solar Eclipse (universetoday.com)
- An Awesome Annular Eclipse! Images and Videos from Earth and Space (universetoday.com)
- ‘Ring of fire’ eclipse wows Australians (science.nbcnews.com)
- How to Catch This Week’s ‘Ring of Fire’ Annular Eclipse (universetoday.com)
- ‘Ring of Fire’ Solar Eclipse of May 2013: Photos and Maps (space.com)
- Scientists converge for annular solar eclipse (abc.net.au)
- VIDEO: ‘Gorgeous’ solar eclipse in Australia (bbc.co.uk)
- Ring of fire annular solar eclipse 9 May – 10 May 2013 (harounkola.com)
- Annular Solar Eclipse Of May 10, 2013… (fox41blogs.typepad.com)
- How can I watch the May 9-10 solar eclipse safely … or online? (earthsky.org)
Hawaii set to build telescope capable of viewing the beginning of time | Science Recorder
Posted by Michael B. Calyn in Astronomy on April 15, 2013
Hawaii set to build telescope capable of viewing the beginning of time
Hawaii clears final hurdle in bid to build a massive telescope.
|
|
|
Photo credit: University of Hawaii Hilo |
Science Recorder | Delila James | Sunday, April 14, 2013
The Hawaii Board of Land and Natural Resources has reportedly granted a permit to the University of Hawaii at Hilo for the construction of the $1.3 billion Thirty Meter Telescope (TMT). The telescope will be built atop Mauna Kea and will be one of the largest telescopes in the world, according to the university.
The TMT has been in development for over a decade, but the large amount of land needed for its construction raised concerns over the environmental and cultural impact of such a project. Now, however, the land board has rendered a final decision, saying that the university had satisfied the eight criteria necessary under Hawaiian state law to allow the venture to go forward.
The giant TMT will be an optical and infrared telescope with enough coverage area and sharpness to observe light from 13 billion years ago, track extrasolar planets, and observe planets and stars in their early formative years.
According to University of Hawaii officials, the land board’s decision “marked another important step forward for the future of astronomical discovery and economic opportunity on Hawaii Island.”
“It’s a billion-dollar project. It’s going to affect businesses, bring in a lot of grant money, researchers and astronomers,” Jerry Chang, UH-Hilo’s director of university relations, told Pacific Business News.
Challenges to the land board’s grant of the permit for the TMT came from organizations and individuals concerned over the environmental effects of the telescope on the surrounding region. In its decision, however, the board said that enormous telescope would serve as a benefit to the public, creating as many as 140 full-time jobs.
The board’s decision also mandated that certain conditions attach to the permit. The TMT will be required to pay a “substantial” amount in rent, which will be used for the management of Mauna Kea. It also must pay $1 million a year for a “community benefits package,” to be administered by the Hawaii Island New Knowledge Fund’s board of advisors. In addition, the telescope’s employees must take cultural and natural resources training and will be required to work with the Imiloa Astronomy Center and the Office of Mauna Kea to develop exhibits for visitors about the natural, cultural and archaeological resources at Mauna Kea.
According to the a statement released by the university, the TMT will now seek final approval of its construction plans by Hawaii’s Department of Land and Natural Resources (DLNR), before moving on to negotiate a sublease with the University of Hawaii. TMT intends to begin preparing the ground for construction on Mauna Kea before the end of the year. The construction start date is slated for April, 2014.
The TMT is made possible through a partnership by a number of governments and research universities. These include the University of California, the California Institute of Technology, the Association of Canadian Universities for Research in Astronomy, and the governments of the United States, China, India, Japan, and Canada.
Hawaii set to build telescope capable of viewing the beginning of time | Science Recorder.
Related articles
- Construction of World’s Largest Optical Telescope Approved (science.slashdot.org)
- Hawaii land board grants use permit for $1.3B Thirty Meter Telescope (bizjournals.com)
- Hawaiian Officials Okay Plans To Build 30-Meter, $1.3 Billion Telescope Atop Mauna Kea (natureworldnews.com)
- Construction of world’s largest optical telescope approved – CNET (blog) (news.cnet.com)
- Thirty Meter Telescope project starts in 2014 (techandle.com)
- Hawaii approves plan to build world’s largest telescope atop Mauna Kea (ctvnews.ca)
- Land For Thirty Meter Telescope Finally Okayed By Hawaii (ubergizmo.com)
- Hawaii clears land use for the Thirty Meter Telescope, construction to start in 2014 (engadget.com)
- Hawaii land board approves Thirty Meter Telescope (cnsnews.com)
- Hawaii land board approves Thirty Meter Telescope (rdmag.com)
Vulcan and Cerberus win online poll to name Pluto’s smallest moons – latimes.com
Posted by Michael B. Calyn in Astronomy on February 26, 2013
Vulcan and Cerberus win online poll to name Pluto’s smallest moons
|
This artists’ rendering from NASA depicts how Pluto might look from the surface of one it’s three bigger moons. The two smallest moons may be named Vulcan and Kerberos. (NASA/JPL and G. Bacon (STSci) / February 25, 2013) |
By Karen Kaplan
February 25, 2013, 4:30 p.m.
The people have spoken, and they would like the two smallest moons of Pluto to be named Vulcan and Cerberus.
When scientists at the SETI Institute stopped accepting new votes on the Pluto Rocks website at 9 a.m. Pacific time Monday, Vulcan was the only candidate with more than 100,000 votes. In fact, it blew away the rest of the field with 174,062 votes from people all over the world.
The biggest fan of the name has got to be William Shatner, who suggested it in a tweet on Feb. 12.
“So what do you think of the idea of naming the two moons of Pluto Vulcan and Romulus?” he asked of his 1.35 million followers. One day later, he tweeted this update: “Did you hear? They added the name Vulcan to the list of possible names for Pluto’s moons! You did it! I’m so happy.” Then he exhorted his followers to vote for Vulcan more than a dozen times with tweets such as this: “It’s a new day- at least here in Los Angeles- have you voted for Vulcan?”
On Monday morning, he shared the news: “174,062 votes and Vulcan came out on top of the voting for the naming of Pluto’s moons. Thank you to all who voted!”
Vulcan, of course, is the home planet of the Vulcans of Star Trek fame. Spock, who served along with Captain James T. Kirk (played by Shatner), has Vulcan heritage. Romulus is the home planet of the Romulans, the antagonistic beings who are related to Vulcans but have the opposite temperament.
At first, election organizer Mark Showalter, a planetary astronomer with SETI’s Carl Sagan Center for the Study of Life in the Universe, doubted that either name was worthy of serious consideration for P4 and P5, the temporary names for Pluto’s fourth and fifth moons. After all, there are rules, he explained on the election website Pluto Rocks: “By tradition, the names of Pluto’s moons come from Greek and Roman mythology, and are related to the ancient tales about Hades and the Underworld.”
Romulus was a non-starter because it has already been used to name one of the moons of the asteroid Sylvia. (The other moon is called Remus.)
Vulcan was a little more complicated. It’s the name of the Roman god of fire, so it satisfies the mythology requirement. But it’s also the name of a nonexistent planet that was once thought to orbit the Sun even closer than Mercury.
“Some of the world’s greatest astronomers spent quite a long time looking for it and they never saw it because it isn’t there,” Showalter explained in a Google+ hangout. “Some people say, ‘No, we should save the name Vulcan for some place that’s big and hot.’ I guess one response to that would be, ‘Well, we found all the places [in the solar system] that are big and hot and they’ve all got names now.’”
So Vulcan was added to the ballot and it blew away the competition.
The second-place finisher with 99,432 votes was Cerberus, the Roman name for the three-headed dog that guards the entrance to the underworld. Although this was one of the official nominees from SETI, it turned out to be a little tricky too. The solar system is already home to an asteroid by that name, Showalter noted. One potential solution would be to change the spelling to Kerberos, as the creature is known in Greek mythology, he said.
Rounding out the top five were Styx (87,858 votes), Persephone (68,969 votes) and Orpheus (51,197 votes).
More than 450,000 total votes were cast (some people may have voted more than once), with about half of those coming from the United States. The ballot was available in more than a dozen languages, including Russian, Chinese, Korean, Japanese, Arabic and Farsi. “Almost every country on the planet has had at least a couple of votes come in,” Showalter said.
The final decision will be made by the nomenclature working group of the International Astronomical Union. Showalter is a member of that committee, but he pledged to recuse himself from the deliberations when the permanent names for P4 and P5 are considered a few months from now.
Vulcan and Cerberus win online poll to name Pluto’s smallest moons – latimes.com.
Related articles
- ‘Vulcan’ wins Pluto moon name vote (spacedaily.com)
- Pluto’s Two New Moons Have Names. One of Them is “Vulcan” (tor.com)
- “Vulcan” has won Pluto’s moon-naming poll! (io9.com)
- Vulcan tops vote to name Pluto moons (bbc.co.uk)
- ‘Vulcan’ and ‘Cerberus’ Win Pluto Moon Naming Poll (space.com)
- Pluto’s Newest Moon Voted to be Named ‘Vulcan’ After Spock’s Planet (laughingsquid.com)
- Pluto May Soon Have a Moon Named Vulcan (Thanks to William Shatner) (universetoday.com)
- Pluto’s new moon named Vulcan by Star Trek fans rallying to William Shatner’s call (metro.co.uk)
- ‘Capt. Kirk’ wins Pluto contest (news.yahoo.com)
- Online Vote Picks Vulcan as Name for Pluto’s Fourth Moon (escapistmagazine.com)
Russian Meteor Likely An Apollo Asteroid Chunk : Discovery News
Posted by Michael B. Calyn in Astronomy, Space on February 26, 2013
Russian Meteor Likely An Apollo Asteroid Chunk
FEB 26, 2013 12:25 PM ET // BY IAN O’NEILL
On Feb. 15, the Urals region of Russia played host to a noisy cosmic visitor. A meteor entered the atmosphere and broke up over the city of Chelyabinsk, generating powerful shockwaves that slammed into the city, blowing out windows, causing 1,500 injuries and millions of dollars-worth of damage. Before it collided with Earth, however, the Chelyabinsk space rock was a 10,000 ton meteoroid and astronomers now think they know where it came from.
PHOTOS: Russian Meteor Strike Aftermath
Helped by the extensive coverage of eyewitness cameras, CCTV footage and a fortuitous observation made by the Meteosat-9 weather satellite, Jorge Zuluaga and Ignacio Ferrin of the University of Antioquia in Medellin, Colombia, have been able to reconstruct the most likely orbit of the space rock around the sun before the Earth got in its way. What’s more, they know what typeof space rock it was.
Using video evidence (most of which had precise timestamps), the location, speed and altitude of the fireball could be estimated. Add to that the location where a suspected meteorite fragment punched a hole into the ice of Lake Cherbakul and it’s a case of using some simple math to learn the characteristics of the object. But to trace the meteoroid’s path back out into space and assemble its orbital trajectory around the sun wasn’t so straight forward, according to the arXiv blog.
ANALYSIS: Russian Meteor: What’s With All The Dash Cams?
However, this analysis hinges on one important factor: “Assuming that the hole in the ice sheet of Lake Cherbakul was produced by a fragment of the meteoroid is also a very important hypothesis of this work. More importantly, our conclusions relies strongly onto assume that the direction of the trajectory of the fragment responsible for the breaking of the ice sheet in the Lake, is essentially the same as the direction of the parent body. It could be not the case. After the explosion and fragmentation of the meteoroid fragments could acquire different velocities and fall affecting areas far from the region where we expect to find,” the researchers write in their paper submitted to the arXiv pre-print service. So far, no meteorite has been recovered from Lake Cherbakul.
“According to our estimations, the Chelyabinski meteor started to brighten up when it was between 32 and 47 km up in the atmosphere … The velocity of the body predicted by our analysis was between 13 and 19 km/s (relative to the Earth) which encloses the preferred figure of 18 km/s assumed by other researchers,” they add.
Armed with this wealth of data farmed from various eyewitness sources, they used a piece of software called NOVAS (an acronym for “Naval Observatory Vector Astrometry Software”) developed by the U.S. Navy Observatory (USNO). This sophisticated program was able to consider the gravitational influence of the moon, plus eight other bodies in the solar system, ultimately helping Zuluaga and Ferrin track where the object was before impact.
NEWS: Huge Meteor Explodes Over Russia
Taking its orbit into account, the researchers were able to conclude that the Chelyabinsk-bound meteoroid originated from an Apollo-class asteroid. Apollo asteroids are well-known near-Earth asteroids that cross the orbit of Earth. Around 5,200 Apollo asteroids are currently known, the largest being 1866 Sisyphus — a 10 kilometer-wide monster that was discovered in 1972.
Large Apollos are identified as being a significant risk to our planet, so the Chelyabinsk meteoroid acted like an Apollo warning shot.
Russian Meteor Likely An Apollo Asteroid Chunk : Discovery News.
Related articles
- Russian Meteor Likely An Apollo Asteroid Chunk (news.discovery.com)
- Russian Meteor Likely an Apollo Asteroid Chunk (science.slashdot.org)
- Astronomers work out the final orbit of the Russian meteor (independent.co.uk)
- Astronomers Calculate Orbit and Origins of Russian Fireball (universetoday.com)
- Russian Meteorite Reconstructed, Source Discovered [VIDEO] (counselheal.com)
- Russia’s meteor came from asteroid belt between Mars and Jupiter, researchers claim (dailymail.co.uk)
- Amateur sleuth, scientists team up to reconstruct path of Russian meteor (ctvnews.ca)
- Was that Fireball a Meteor or a Meteorite? (thelede.blogs.nytimes.com)
- Russia meteor’s origin tracked down (bbc.co.uk)
- NASA: What exploded over Russia? (wtvr.com)
Fermi Measures Light from All the Stars That Have Ever Existed
Posted by Michael B. Calyn in Astronomy on November 4, 2012
Fermi Measures Light from All the Stars That Have Ever Existed
by NANCY ATKINSON on NOVEMBER 1, 2012
Want to stay on top of all the space news? Follow @universetoday on Twitter
This plot shows the locations of 150 blazars (green dots) used in the a new by the Fermi Gamma-Ray Telescope. Credit: NASA/DOE/Fermi LAT Collaboration
All the light that has been produced by every star that has ever existed is still out there, but “seeing” it and measuring it precisely is extremely difficult. Now, astronomers using data from NASA’s Fermi Gamma-ray Space Telescope were able to look at distant blazars to help measure the background light from all the stars that are shining now and ever were. This enabled the most accurate measurement of starlight throughout the universe, which in turn helps establish limits on the total number of stars that have ever shone.
“The optical and ultraviolet light from stars continues to travel throughout the universe even after the stars cease to shine, and this creates a fossil radiation field we can explore using gamma rays from distant sources,” said lead scientist Marco Ajello from the Kavli Institute for Particle Astrophysics and Cosmology at Stanford University in California and the Space Sciences Laboratory at the University of California at Berkeley.
Their results also provide a stellar density in the cosmos of about 1.4 stars per 100 billion cubic light-years, which means the average distance between stars in the universe is about 4,150 light-years.
The total sum of starlight in the cosmos is called the extragalactic background light (EBL), and Ajello and his team investigated the EBL by studying gamma rays from 150 blazars, which are among the most energetic phenomena in the universe. They are galaxies powered by extremely energetic black holes: they have energies greater than 3 billion electron volts (GeV), or more than a billion times the energy of visible light.
The astronomers used four years of Fermi data on gamma rays with energies above 10 billion electron volts (GeV), and the Fermi Large Area Telescope (LAT) instrument is the first to detect more than 500 sources in this energy range.
To gamma rays, the EBL functions as a kind of cosmic fog, but Fermi measured the amount of gamma-ray absorption in blazar spectra produced by ultraviolet and visible starlight at three different epochs in the history of the universe.
Fermi measured the amount of gamma-ray absorption in blazar spectra produced by ultraviolet and visible starlight at three different epochs in the history of the universe. (Credit: NASA’s Goddard Space Flight Center)
“With more than a thousand detected so far, blazars are the most common sources detected by Fermi, but gamma rays at these energies are few and far between, which is why it took four years of data to make this analysis,” said team member Justin Finke, an astrophysicist at the Naval Research Laboratory in Washington.
Gamma rays produced in blazar jets travel across billions of light-years to Earth. During their journey, the gamma rays pass through an increasing fog of visible and ultraviolet light emitted by stars that formed throughout the history of the universe.
Occasionally, a gamma ray collides with starlight and transforms into a pair of particles — an electron and its antimatter counterpart, a positron. Once this occurs, the gamma ray light is lost. In effect, the process dampens the gamma ray signal in much the same way as fog dims a distant lighthouse.
From studies of nearby blazars, scientists have determined how many gamma rays should be emitted at different energies. More distant blazars show fewer gamma rays at higher energies — especially above 25 GeV — thanks to absorption by the cosmic fog.
The researchers then determined the average gamma-ray attenuation across three distance ranges: The closest group was from when the universe was 11.2 years old, a middle group of when the Universe was 8.6 billion years old, and the farthest group from when the Universe was 4.1 billion years old.
This animation tracks several gamma rays through space and time, from their emission in the jet of a distant blazar to their arrival in Fermi’s Large Area Telescope (LAT). During their journey, the number of randomly moving ultraviolet and optical photons (blue) increases as more and more stars are born in the universe. Eventually, one of the gamma rays encounters a photon of starlight and the gamma ray transforms into an electron and a positron. The remaining gamma-ray photons arrive at Fermi, interact with tungsten plates in the LAT, and produce the electrons and positrons whose paths through the detector allows astronomers to backtrack the gamma rays to their source.
From this measurement, the scientists were able to estimate the fog’s thickness.
“These results give you both an upper and lower limit on the amount of light in the Universe and the amount of stars that have formed,” said Finke during a press briefing today. “Previous estimates have only been an upper limit.”
And the upper and lower limits are very close to each other, said Volker Bromm, an astronomer at the University of Texas, Austin, who commented on the findings. “The Fermi result opens up the exciting possibility of constraining the earliest period of cosmic star formation, thus setting the stage for NASA’s James Webb Space Telescope,” he said. “In simple terms, Fermi is providing us with a shadow image of the first stars, whereas Webb will directly detect them.”
Measuring the extragalactic background light was one of the primary mission goals for Fermi, and Ajello said the findings are crucial for helping to answer a number of big questions in cosmology.
A paper describing the findings was published Thursday on Science Express.
Fermi Measures Light from All the Stars That Have Ever Existed.
Related articles
- NASA’s Fermi Measures Cosmic ‘Fog’ Produced by Ancient Starlight (spacefellowship.com)
- Astronomers Read the Shadows of the Universe’s Earliest Stars (theatlantic.com)
- Astronomers detect traces of light from the universe’s very first stars – which may be nearly as old as time itself (dailymail.co.uk)
- Fermi Space Telescope measures cosmic fog caused by ancient starlight (wired.co.uk)
- Found: The Very First Stars (science.time.com)
- NASA’s Fermi measures cosmic ‘fog’ produced by ancient starlight (esciencenews.com)
- Cosmic ‘fog’ from ancient starlight measured – Zee News (zeenews.india.com)
- Fermi Measures Light from All the Stars That Have Ever Existed (universetoday.com)
- Fermi Measures Ancient Starlight’s Cosmic ‘Fog’ (nasa.gov)
- Scientists Find The Light Of The Earliest Stars Using Black Holes (forbes.com)
Rare Supernova Pair are Most Distant Ever
Posted by Michael B. Calyn in Astronomy on November 3, 2012
Rare Supernova Pair are Most Distant Ever
by NANCY ATKINSON on NOVEMBER 2, 2012
Want to stay on top of all the space news? Follow @universetoday on Twitter
High-resolution simulation of a galaxy hosting a super-luminous supernova and its chaotic environment in the early Universe. Credit: Adrian Malec and Marie Martig (Swinburne University)
Some of the earliest stars were massive and short-lived, destined to end their lives in huge explosions. Astronomers have detected some of the earliest and most distant of these exploding stars, called ‘super-luminous’ supernovae — stellar explosions 10–100 times brighter than other supernova types. The duo sets a record for the most distant supernova yet detected, and offers clues about the very early Universe.
“The light of these supernovae contains detailed information about the infancy of the Universe, at a time when some of the first stars are still condensing out of the hydrogen and helium formed by the Big Bang,” said Dr. Jeffrey Cooke, an astrophysicist from Swinburne University of Technology in Australia, whose team made the discovery.
The team used a combination of data from the Canada-France-Hawaii Telescope and the Keck 1 Telescope, both located in Hawaii.
“The type of supernovae we’ve found are extremely rare,” Cooke said. “In fact, only one has been discovered prior to our work. This particular type of supernova results from the death of a very massive star (about 100 – 250 times the mass of our Sun) and explodes in a completely different way compared to other supernovae. Discovering and studying these events provides us with observational examples to better understand them and the chemicals they eject into the Universe when they die.”
Super-luminous supernovae were discovered only a few years ago, and are rare in the nearby Universe. Their origins are not well understood, but a small subset of them are thought to occur when extremely massive stars, 150 to 250 times more massive than our Sun, undergo a nuclear explosion triggered by the conversion of photons into electron-positron pairs. This process is completely different compared to all other types of supernovae. Such events are expected to have occurred more frequently in the early Universe, when massive stars were more common.
This, and the extreme brightness of these events, encouraged Cooke and colleagues to search for super-luminous supernovae at redshifts, z, greater than 2, when the Universe was less than one-quarter of its present age.
“We used LRIS (Low Resolution Imaging Spectrometer) on Keck I to get the deep spectroscopy to confirm the host redshifts and to search for late-time emission from the supernovae,” Cooke said. “The initial detections were found in the CFHT Legacy Survey Deep fields. The light from the supernovae arrived here on Earth 4 to 6 years ago. To confirm their distances, we need to get a spectrum of their host galaxies which are very faint because of their extreme distance. The large aperture of Keck and the high sensitivity of LRIS made this possible. In addition, some supernovae have bright enough emission features that persist for years after they explode. The deep Keck spectroscopy is able to detect these lines as a further means of confirmation and study.”
Cooke and co-workers searched through a large volume of the Universe at z greater than or equal to 2, and found two super-luminous supernovae, at redshifts of 2.05 and 3.90 — breaking the previous supernova redshift record of 2.36, and implying a production rate of super-luminous supernovae at these redshifts at least 10 times higher than in the nearby Universe. Although the spectra of these two objects make it unlikely that their progenitors were among the first generation of stars, the present results suggest that detection of those stars may not be far from our grasp.
Detecting the first stars allows us much greater understanding of the first stars in the Universe, Cooke said.
“Shortly after the Big Bang, there was only hydrogen and helium in the Universe,” he said. “All the other elements that we see around us today, such as carbon, oxygen, iron, and silicon, were manufactured in the cores of stars or during supernova explosions. The first stars to form after the Big Bang laid the framework for the long process of enriching the Universe that eventually produced the diverse set of galaxies, stars, and planets we see around us today. Our discoveries probe an early time in the Universe that overlaps with the time we expect to see the first stars.”
Rare Supernova Pair are Most Distant Ever.
Related articles
- Rare Supernova Pair are Most Distant Ever (universetoday.com)
- Two Superluminous Supernovae Discovered (sci-news.com)
- Oldest, Farthest Star Explosions Discovered in Distant Universe (space.com)
- Super-rare, super-luminous supernovae are likely explosion of universe’s earliest stars (eurekalert.org)
- Superbright star explosion is most distant known (newscientist.com)
- Oldest, farthest supernova explosions discovered (mnn.com)
- Distant super-luminous supernovae found (spacedaily.com)
- Astronomers Spot The Oldest Star Explosions Ever (businessinsider.com)
- Two massive stars which exploded 12.5bn years ago are ‘the oldest supernovae yet found’ (dailymail.co.uk)
- Twin dazzling supernovas detected (vancouverdesi.com)
Astrophoto: Star Trails from Italy
Posted by Michael B. Calyn in Astronomy on June 19, 2012
Astrophoto: Star Trails from Italy
by NANCY ATKINSON on JUNE 18, 2012
Caption: ‘Cerchi di stelle’ — Circles of stars. Credit: Gerlos on Flickr.
This beautiful view of star trails was captured by Gerlos on Flickr, as seen in the skies over Petralia, Sottana, Sicily, Italy on June 16, 2012. Gerlos said the image is a “composition of 363 shots (+10 dark frames) taken for 25 seconds every 30 seconds between 1:55 and 4:23 at f / 4 and ISO 1600 with Canon 550D, EF-S 18-55 lens + extra wide field Opteka 0.45 HD². Images acquired using the function of the interval Magic Lanternand made using StarStax.
Astrophoto: Star Trails from Italy.
Related articles
- Astrophoto: Star Trails from Italy (universetoday.com)
- Amazing Astrophoto: The Phases of Venus (universetoday.com)
- Astrophoto: A Smokestack on the Sun by Monty Leventhal (universetoday.com)
- Astrophoto: Meteor Fireball Passing through the Milky Way (sott.net)
- I want one! (astronomyandlaw.com)
- Spring has sprung in Sicily (essentialitaly.typepad.com)
- Italy Renders the Tiebreakers Moot (blogs.wsj.com)
- Italy into Euro 2012 quarter-finals with 2-0 win over Ireland (vancouversun.com)
- Photography Under the Stars (digital-photography-school.com)
- Sarah’s 5 favourite dishes in Puglia (essentialitaly.typepad.com)
On the Edge of Titan
Posted by Michael B. Calyn in Astronomy, Cool Stuff!, Space on June 10, 2012
On the Edge of Titan
by JASON MAJOR on JUNE 9, 2012
Titan’s haze-covered limb seen by Cassini on June 6
Here’s a quick look at one of my favorite cosmic photo subjects – the varying layers of atmosphere that enshroud Saturn’s enormous moon Titan. The image above is a color-composite made from three raw images acquired by Cassini during its latest flyby.
On June 7 Cassini approached Titan within 596 miles (959 km) and imaged portions of the moon’s northwest quadrant with its radar instrument, as well as conducted further investigations of areas near the equator where surface changes were detected in 2010.
The image here was assembled from three raw images captured in red, green and blue visible light channels. It reveals some structure in the upper hydrocarbon haze layers that extend upwards above the moon’s opaque orange clouds — reaching 400-500 km in altitude, Titan’s atmosphere is ten times thicker than Earth’s!
The June 6 flyby was the second in a series of passes that will take Cassini into a more inclined orbit, where it will reside for the next three years as it investigates Saturn’s polar regions and obtains better views of its ring system.
Read more about the flyby here.
Related articles
- Cassini Spots Tiny Moon, Begins to Tilt Orbit (spacefellowship.com)
- Cassini spots tiny moon, begins to tilt orbit (phys.org)
- A New Angle on Titan (universetoday.com)
- Spectacular View Of Saturn’s Moon Dione Captured As Cassini Probe Hurtles Past (ritholtz.com)
- Cassini Spots Tiny Moon, Begins to Tilt Orbit (saturndaily.com)
- Moon Methone Meets Cassini (science.slashdot.org)
- Pretty pictures from Cassini’s recent Dione flyby (planetary.org)
- Take a Look at Titan! (possiblynonsense.wordpress.com)
- Cassini Spacecraft Snaps Saturn Moon Pics, Changes Orbit (livescience.com)
The End Of Envisat
Posted by Michael B. Calyn in Astronomy, Science, Space on May 14, 2012
The End Of Envisat
by JASON MAJOR on MAY 13, 2012
After ten years in orbit Envisat’s mission has been declared over. (ESA)
Well, it’s official. After ten years of groundbreaking observation of our planet, ESA has declared the end of the Envisat mission after losing contact with the satellite on April 8, 2012. All attempts to re-establish communication with Envisat have so far been unsuccessful, and although recovery teams will continue to determine the cause of signal loss and try to regain a signal over the next several weeks, the mission — and the satellite — have been retired.
Having performed twice as long as originally planned, the hardworking Envisat has definitely earned its rest.
On April 8, the European Space Agency lost communication with the Earth-observation satellite, preventing reception of data as it passed over the Kiruna station in Sweden. Although later confirmed that the satellite is still in orbit, the recovery team has not been able to re-establish contact.
It’s thought that a loss of a power regulator could be blocking telemetry and telecommands from reaching Envisat, or else the satellite may have experienced a short-circuit and attempted to go into “safe mode” but experienced difficulties during the transition, leaving it in an unknown state.
Read: Is This the Last Image From Envisat?
ESA states that the chances of ever regaining communication with Envisat are extremely low.
While we had reported before on the last image received before falling silent, the image below is actually the final image from Envisat, an X-band image of the Canary Islands.
The final image from Envisat, acquired on April 8, 2012. (ESA/Edisoft)
During its lifetime, Envisat completed 50,000 orbits of Earth and returned over a thousand terabytes of data, containing invaluable measurements of our planet’s surface and atmosphere that were used in more than 2500 science publications.
The video below gives a fitting eulogy for a satellite that’s definitely overachieved and over-performed, giving us a decade of crucial observations of our world from orbit.
Read more on the ESA news release here.
Related articles
- Dead Satellite Envisat May Be Space Junk for 150 Years (huffingtonpost.com)
- Huge satellite Envisat is dead in space (cbsnews.com)
- ENVISAT declared dead in space (wattsupwiththat.com)
- ESA Declares Flagship Envisat Observing Satellite Lost (science.slashdot.org)
- Did dicky power supply silence climate-change probe Envisat? (go.theregister.com)
- Is This The Last Image From Envisat? (universetoday.com)
- Satellite Envisat is dead, says European Space Agency (mnn.com)
- ESA’s Ailing Envisat Imaged by Another Earth Orbiting Satellite (universetoday.com)
- Txch Today: Re-Growing Teeth, Parachuting Mice Fight Snakes, The Envisat is Declared Dead (txchnologist.com)
End of the World Averted: New Archeological Find Proves Mayan Calendar Doesn’t End
Posted by Michael B. Calyn in Astronomy, Cool Stuff!, History on May 13, 2012
End of the World Averted: New Archeological Find Proves Mayan Calendar Doesn’t End
by NANCY ATKINSON
William Saturno, a Boston University archeologist, excavates a mural in a house in Xultun, massive Mayan ruins in Guatemala. The mural depicts a figure who may have been the town scribe. Excavation and preservation of the site were supported by the National Geographic Society. Credit: Tyrone Turner © 2012 National Geographic.
So much for the world ending on December 21, 2012. We’ve been saying it for years, but a new find by archaeologists confirms the Mayan calendar indeed does not end this year but keeps going, just like turning a page to a new calendar.
“It’s very clear that the 2012 date, while important as Baktun 13, was turning the page,” David Stuart, quoted by Alan Boyle on MSNBC’s Cosmic Log. “Baktun 14 was going to be coming, and Baktun 15 and Baktun 16. … The Maya calendar is going to keep going, and keep going for billions, trillions, octillions of years into the future.”
A team of archaeologists found a small room in Mayan ruins where royal scribes wrote on the walls — apparently like a blackboard — to keep track of astronomical records and details of the complex Mayan calendar. The writings date to about 1,200 years ago.
These are the oldest known astronomical tables from the Maya. They were found at the Xultun archaeological site in Guatemala’s Peten region. Scientists already knew the Mayans must have been keeping such records during that time period, but until now the oldest known examples dated from about 600 years later.
The room, about 2 meters (6-feet) square, contains walls decorated with images of a king and some other notable figures, as well as astronomical numbers and writings, the scientists said. The room had a stone roof rather than a thatched one, which may indicate the importance of the room.
Why did they write on walls, as opposed to other Mayan texts that have been found on bark paper?
The time period of the early 9th century was not a stable time for the Mayans, as there was political turmoil between the various city-states of the time, and the researchers said that perhaps the Xultun scribes wished to make a more permanent record of their data related to the calendar.
By some supposed “researchers,” Dec. 21, 2012 has been correlated to the end of the Mayan Long Count calendar, which was based on a cycle of 13 intervals known as baktuns, each lasting 144,000 days.
But the newly found writing on walls of the ancient room shows wide ranges of accumulated time, including a 17-baktun period. “There was a lot more to the Maya calendar than just 13 baktuns,” said Stuart, talking with reporters. Seventeen baktuns would stand for about 6,700 years, which is much longer than the 13-baktun cycle of 5,125 years. However, Stuart cautioned that the time notation shouldn’t be read as specifying a date that’s farther in the future than Dec. 21.
“It may just be that this is a mathematical number that’s kind of interesting,” he said. “We’re not sure what the base of the calendar is.”
William Saturno, an archaeologist at Boston University who led the team of archaeologists said many different scientists have been trying to get the word out that the end of the Maya culture’s 13-baktun Long Count calendar doesn’t signify the end of the world, but merely a turnover to the next cycle in a potentially infinite series — like going from Dec. 31 to Jan. 1 on a modern calendar.
“If someone is a hard-core believer that the world is going to end in 2012, no painting is going to convince them otherwise,” he said. “The only thing that can convince them otherwise is waiting until Dec. 22, 2012 — which fortunately for all of us isn’t that far away.”
End of the World Averted: New Archeological Find Proves Mayan Calendar Doesn’t End.
Related articles
- Ancient Mysteries – Re: Scrub 2012 – Earliest Mayan Calendar Found (disclose.tv)
- The World Isn’t Ending! (thedailybeast.com)
- Oldest Mayan calendar found, and it goes way beyond Dec. 12, 2012 (+video) (csmonitor.com)
- Oldest Mayan calendar found, and it goes way beyond Dec. 12, 2012 (csmonitor.com)
- Re-cycled Mayan calendar nonsense (blogs.discovermagazine.com)
- Oldest Mayan Astronomical Calendar Discovered (space.com)
- Oldest Known Mayan Calendar Found, Safe to Make Plans for 2013 (blippitt.com)
- Nevermind the Apocalypse: Earliest Mayan Calendar Found #Follow @DJIVREAL (djivreal.com)
- Nevermind the Apocalypse: Earliest Mayan Calendar Found (livescience.com)
-
You are currently browsing the archives for the Astronomy category.
Recent Comments