Infrared image of globular cluster 47 Tucanae (NGC 104) captured by ESO’s VISTA telescope.
“My god, it’s full of stars!” said Dave Bowman in the movie 2010 as he entered the monolith, and one could imagine that the breathtaking view before him looked something like this.
Except this isn’t science fiction, it’s reality — this is an image of globular cluster 47 Tucanae taken by the European Southern Observatory’s VISTA telescope at the Paranal Observatory in Chile. It reveals in stunning detail a brilliant collection of literally millions of stars, orbiting our Milky Way galaxy at a distance of 15,000 light-years.
The full image can be seen below.
47 Tucanae (also known as NGC 104) is located in the southern constellation Tucana. It’s bright enough to be seen without a telescope and, even though it’s very far away for a naked-eye object, covers an area about the size of the full Moon.
In reality the cluster is 124 light-years across.
Although globular clusters like 47 Tucanae are chock-full of stars — many of them very old, even as stars go — they are noticeably lacking in clouds of gas and dust. It’s thought that all the gaseous material has long since condensed to form stars, or else has been blown away by radiation and outbursts from the cluster’s exotic inhabitants.
At the heart of 47 Tucanae lie many curious objects like powerful x-ray sources, rapidly-spinning pulsars, “vampire” stars that feed on their neighbors, and strange blue stragglers — old stars that somehow manage to stay looking young. (You could say that a globular cluster is the cosmic version of a trashy reality show set in Beverly Hills.)
Red giants can be seen surrounding the central part of the cluster, old bloated stars that are running out of fuel, their outer layers expanding.
The background stars in the image are part of the Small Magellanic Cloud, which was in the distance behind 47 Tucanae when this image was taken.
VISTA is the world’s largest telescope dedicated to mapping the sky in near-infrared wavelengths. Located at ESO’s Paranal Observatory in Chile, VISTA is revealing new views of the southern sky. Read more about the VISTA survey here.
Asteroid Apophis was discovered on June 19, 2004. Image credit: UH/IA
During its close approach this week, observatories from ESA and NASA have made some updates on their assessment of asteroid Apophis and its future encounters with Earth. While the Herschel Space Telescope observations indicates the asteroid is bigger and less reflective than first estimated, scientists at the Jet Propulsion Laboratory have effectively ruled out the possibility that this asteroid will impact Earth during a close flyby in 2036.
Repeat after me: Asteroid Apophis is not a threat to Earth in 2029 or 2036. Got that doomsday prognosticators?
Discovered in 2004, Apophis garnered lots of attention when initial calculations of its orbit indicated a 2.7 percent possibility of an Earth impact during a close flyby in 2029. Data discovered during a search of old astronomical images provided the additional information required to rule out the 2029 impact scenario, but a remote possibility of one in 2036 remained – until now.
ESA’s Herschel Space Observatory captured asteroid Apophis in its field of view during the approach to Earth on 5/6 January 2013. This image shows the asteroid in Herschel’s three PACS wavelengths: 70, 100 and 160 microns, respectively. Credit: ESA/Herschel/PACS/MACH-11/MPE/B.Altieri (ESAC) and C. Kiss (Konkoly Observatory)
Herschel provided the first thermal infrared observations of Apophis at different wavelengths, which together with optical measurements helped refine estimates of the asteroid’s properties. Previous estimates bracketed the asteroid’s average diameter at 270 ± 60 m; the new Herschel observations returned a more precise diameter of 325 ± 15 m.
“The 20% increase in diameter, from 270 to 325 m, translates into a 75% increase in our estimates of the asteroid’s volume or mass,” says Thomas Müller of the Max Planck Institute for Extraterrestrial Physics in Garching, Germany, who is leading the analysis of the new data.
By analyzing the heat emitted by Apophis, Herschel also provided a new estimate of the asteroid’s albedo – a measure of its reflectivity – of 0.23. This value means that 23% of the sunlight falling onto the asteroid is reflected; the rest is absorbed and heats up the asteroid. The previous albedo estimate for Apophis was 0.33.
Knowing the thermal properties of an asteroid indicates how its orbit might be altered due to subtle heating by the Sun. Known as the Yarkovsky effect, the heating and cooling cycle of a small body as it rotates and as its distance from the Sun changes can instigate long-term changes to the asteroid’s orbit.
Additional data from the Magdalena Ridge Observatory in New Mexico, the Pan-STARRS observatory in Hawaii and the Goldstone Solar System Radar have provided more conclusive evidence when scientists ran the numbers.
“We have effectively ruled out the possibility of an Earth impact by Apophis in 2036,” said Don Yeomans, manager of NASA’s Near-Earth Object Program Office at JPL. “The impact odds as they stand now are less than one in a million, which makes us comfortable saying we can effectively rule out an Earth impact in 2036. Our interest in asteroid Apophis will essentially be for its scientific interest for the foreseeable future.”
But the flyby on April 13, 2029 will be one for the record books, scientists say. On that date, Apophis will become the closest flyby of an asteroid of its size when it comes no closer than 31,300 kilometers (19,400 miles) above Earth’s surface.
“But much sooner, a closer approach by a lesser-known asteroid is going to occur in the middle of next month when a 40-meter-sized asteroid, 2012 DA14, flies safely past Earth’s surface at about 17,200 miles,” said Yeomans. “With new telescopes coming online, the upgrade of existing telescopes and the continued refinement of our orbital determination process, there’s never a dull moment working on near-Earth objects.”
Goldstone radar observations of Apophis will continue through January 17th, and additional tracking is planned next month with the Arecibo radio dish in Puerto Rico, which should provide even more refinements in Apophis’ orbit.
his composite of the giant barred spiral galaxy NGC 6872 combines visible light images from the European Southern Observatory's Very Large Telescope with far-ultraviolet (1,528 angstroms) data from NASA's GALEX and 3.6-micron infrared data acquired by NASA's Spitzer Space Telescope. Credit: NASA's Goddard Space Flight Center/ESO/JPL-Caltech/DSS
Astronomers have long known that a spectacular barred spiral galaxy named NGC 6872 is a behemoth, but by compiling data from several space- and ground-based observatories and running a few computer simulations, they have now determined this is the largest spiral galaxy we know of.
Measuring tip-to-tip across its two outsized spiral arms, NGC 6872 spans more than 522,000 light-years, making it more than five times the size of our Milky Way galaxy.
“Without GALEX’s ability to detect the ultraviolet light of the youngest, hottest stars, we would never have recognized the full extent of this intriguing system,” said lead scientist Rafael Eufrasio, from the Goddard Space Flight Center the Catholic University of America in Washington. He presented the findings Thursday at the American Astronomical Society meeting in Long Beach, California.
But this galaxy didn’t get so gargantuan all on its own. Astronomers think large galaxies, including our own, grew through mergers and acquisitions — assembling over billions of years by absorbing numerous smaller systems.
The galaxy’s unusual size and appearance stem from its interaction with a much smaller disk galaxy named IC 4970, which has only about one-fifth the mass of NGC 6872. The odd couple is located 212 million light-years from Earth in the southern constellation Pavo.
Intriguingly, the gravitational interaction of NGC 6872 and IC 4970 may have done the opposite, spawning what may develop into a new small galaxy.
“The northeastern arm of NGC 6872 is the most disturbed and is rippling with star formation, but at its far end, visible only in the ultraviolet, is an object that appears to be a tidal dwarf galaxy similar to those seen in other interacting systems,” said team member Duilia de Mello, a professor of astronomy at Catholic University.
The researchers used archived data from the Galaxy Evolution Explorer (GALEX) mission, and studied the galaxy across the spectrum using data from the European Southern Observatory’s Very Large Telescope, the Two Micron All Sky Survey, and NASA’s Spitzer Space Telescope.
While we’re all waiting with bated breath to see what Comet ISON decides to do in 2013, the Solar System is continuing to throw ice balls our way. The latest one keeping astronomers busy is Comet C/2012 K5 (LINEAR), which has been visible in the sky for the last couple of weeks, and should keep us entertained for a few more.
In late December, the comet was a fairly compact iceball, but it flared up nicely in early January, producing a sizable tail, well worth searching for with a set of binoculars or small telescope.
A trio of astrophotographers pooled their efforts on January 4/5 and created this series of time lapses showing the comet from their different equipment setups, and different locations. First up, Mark Behrendt from Chicago, IL used an 8″ Celestron and captured the images using a Canon T3i DSLR camera. Then Cory Schmitz used his 10″ Zhumell Dobsonian telescope, captured images on a Canon T2i from Ames, IA. Finally, Mike Rector in Plattsburg, NY used a Celestron Omni XLT 150, with a Canon 350D camera.
The three time lapses were stitched together by Cory Schmitz into the composite video you’re seeing attached to this article.
Although he wasn’t able to capture a time lapse, Mike Phillips in Apex, NC was able to capture a single long exposure image of the comet using his 14″ homebuilt Newtonian “Akule”.
Comet C/2012 K% (LINEAR) captured by Mike Phillips
Here’s an article from Astrobob giving more details on the comet, and its predicted path over the rest of this month. Bob shares a few more images of the comet taken by astronomers from around the world.
As Bob says, C/2012 K5 is a nice little warmup comet. Nothing dazzling, but a worthwhile challenge to test your astrophotography skills and knowledge of the sky. But in 2013, the sky show is going to get better and better. C/2011 L4 PANSTARRS will arrive in March and provide a much brighter comet in the night sky. And if we’re lucky, ISON will blaze at the end of the year, giving us one of the brightest comets in years.
Want to see more of their work? Mark, Cory and both Mikes are regular participants in our Virtual Star Party, where we connect several telescopes up live into a Google+ Hangout and show what’s happening in the night sky.
Artist's conception of the twin GRAIL spacecraft, called Ebb and Flow. Credit: NASA/JPL-Caltech
As a fond farewell, here are some of the final images taken by the GRAIL MoonKAM educational cameras on board Ebb and Flow, the twin spacecraft for the mission. This footage was shot just three days prior to when the mission ended with the planned impacts on a rim of a crater near the lunar north pole. At that point in the mission, the spacecraft had lowered their orbit to only about 11 km above the lunar surface. While these images aren’t of the highest of resolution, they provide a great sense of what it would be like to orbit close to the Moon. Additionally, they are an inspiration to school children. With MoonKAM (Moon Knowledge Acquired by Middle School Students) the cameras took more than 115,000 total images of the lunar surface, and imaging targets were proposed by middle school students from across the country and the resulting images returned for them to study.
The two probes were purposely crashed into the Moon because they no longer had enough altitude or fuel to continue science operations.
This image from the Mars Hand Lens Imager (MAHLI) on NASA's Mars rover Curiosity shows the patch of rock cleaned by the first use of the rover's Dust Removal Tool (DRT). Image Credit: NASA/JPL-Caltech/MSSS
Justin Lin from the Mars Science Laboratory team gives the latest video update from the Curiosity rover mission. For the first time the rover used its Dust Removal Tool, and the team is looking for a good rock to perform the first use of the drill.
A new comet discovered on January 8, 2013 named Comet P/2013 A2 (SCOTTI) was found remotely from the Haleakala-Faulkes Telescope. Credit: Nick Howes, Ernesto Guido and Peter Phelps.
This week is the BBC’s Stargazing Live, and there have been all sorts of events in the UK for what has become a national stargazing celebration. Excitingly, during one event where astronomers were coordinating imaging with students in UK schools, a new comet was discovered.
“To say we’re over the moon would be an understatement,” said Nick Howes, who is the Faulkes Telescope Pro-Am programme manager. He along with his colleague at the Remanzacco Observatory in Italy, Ernesto Guido helped facilitate the discovery. “This was one of the trickiest comets we’ve ever worked on, faint at magnitude 20, with a minuscule tail. It took all our efforts for several hours to confirm it with the 2 meter scopes. It’s fantastic that with the third episode of Stargazing Live coming up and focusing on comets, that we managed to nail this one during the airing of the live show.”
This is the third year of Stargazing Live, which brings together astronomical societies, museums and discovery centers for local events as well as live broadcasts on the BBC.
Howes and Guido decided on trying to image this target, as analysis of the Minor Planet Centre’s NEOCP target list showed that one of the newly detected but as yet unclassified objects was likely to be a comet.
“We’d selected this target based on the preliminary data published by the minor planet center,” Howes said, “but then the power of social networking helped out even more.”
With only one set of limited observations on it by the Spacewatch Observatory, Howes communicated via the social network site Twitter with Jim Scotti, an astronomer in Arizona, who first observed this object.
“It became clear from speaking to Jim, that they thought they had something, but in following with IAU rules would not say what,” Howes said. “But he encouraged us to perform additional observations to make sure what we had was indeed what we suspected from the orbit…a new comet!”
The new object at magnitude 20, billions of times fainter than the human eye can see was then imaged by Howes and Guido using Faulkes Telescope North.
Fortunately, the elevation of the comet in the sky also permitted them to request additional observations from Peter Phelps at Hazlemere school in the UK. “The data from Faulkes North was not 100% clear, as the object was so faint, but we suspected it was a comet, and asked for more images,” Howes said.
The extra images, from Faulkes South showed the comet very near to a bright field star, but were enough to convince Howes and Guido that it was indeed a comet.
The minor planet center later on the 8th January confirmed this and cited the Faulkes observations in the discovery circular and telegrams:
The new Comet is called P2012 A2 Scotti CBET is 3376 Cbet nr. 3376, issued on 2013, January 08, announces the discovery of a new comet (discovery magnitude 19.5) by J. Scotti with the 691 Steward Observatory, Kitt Peak, on images obtained with the 0.9-m f/3 reflector + CCD on January 06.2. The new comet has been designated P/2013 A2 (SCOTTI).
The team have been observing and imaging comets and asteroids all week with UK schools, and on Wednesday January 9th had a full day devoted to detecting and refining orbits on Kuiper belt objects in the far reaches of the solar system with a large number of schools. This is part of an ongoing research collaboration with the Lowell Observatory in Arizona.
When the Moon was receiving its highest number of impacts, so was Earth. Credit: Dan Durda
Some questions about our own planet are best answered by looking someplace else entirely… in the case of impact craters and when, how and how often they were formed, that someplace can be found shining down on us nearly every night: our own companion in space, the Moon.
By studying lunar impact craters both young and old scientists can piece together the physical processes that took place during the violent moments of their creation, as well as determine how often Earth — a considerably bigger target — was experiencing similar events (and likely in much larger numbers as well.)
With no substantial atmosphere, no weather and no tectonic activity, the surface of the Moon is a veritable time capsule for events taking place in our region of the Solar System. While our constantly-evolving Earth tends to hide its past, the Moon gives up its secrets much more readily… which is why present and future lunar missions are so important to science.
Take the crater Linné, for example. A young, pristine lunar crater, the 2.2-km-wide Linné was formed less than 10 million years ago… much longer than humans have walked the Earth, yes, but very recently on lunar geologic terms.
It was once thought that the circular Linné (as well as other craters) is bowl-shaped, thus setting a precedent for the morphology of craters on the Moon and on Earth. But laser-mapping observations by NASA’s Lunar Reconnaissance Orbiter (at right) determined in early 2012 that that’s not the case; Linné is actually more of a truncated inverted cone, with a flattened interior floor surrounded by sloping walls that rise up over half a kilometer to its rim.
On our planet the erosive processes of wind, water, and earth soon distort the shapes of craters like Linné, wearing them down, filling them in and eventually hiding them from plain sight completely. But in the Moon’s airless environment where the only weathering comes from more impacts they retain their shape for much longer lengths of time, looking brand-new for many millions of years. By studying young craters in greater detail scientists are now able to better figure out just what happens when large objects strike the surface of worlds — events that can and do occur quite regularly in the Solar System, and which may have even allowed life to gain a foothold on Earth.
Most of the craters visible on the Moon today — Linné excluded, of course — are thought to have formed within a narrow period of time between 3.8 and 3.9 billion years ago. This period, called the Late Heavy Bombardment, saw a high rate of impact events throughout the inner Solar System, not only on the Moon but also on Mars, Mercury, presumably Venus and Earth as well. In fact, since at 4 times its diameter the Earth is a much larger target than the Moon, it stands to reason that Earth was impacted many more times than the Moon as well. Such large amounts of impacts introduced material from the outer Solar System to the early Earth as well as melted areas of the surface, releasing compounds like water that had been locked up in the crust… and even creating the sorts of environments where life could have begun to develop and thrive.
(It’s been suggested that there was even a longer period of heavy impact rates nicknamed the “late late heavy bombardment” that lingered up until about 2.5 billion years ago. Read more here.)
In the video below lunar geologist David Kring discusses the importance of impacts on the evolution of the Moon, Earth and eventually life as we know it today:
“Impact cratering in Earth’s past has affected not only the geologic but the biologic evolution of our planet, and we were able to deduce that in part by the lessons we learned by studying the Moon… and you just have to wonder what other things we can learn by going back to the Moon and studying that planetary body further.”
It’s these sorts of connections that make lunar exploration so valuable. Keys to our planet’s past are literally sitting on the surface of the Moon, a mere 385,000 km away, waiting for us to just scoop them up and bring them back. While the hunt for a biological history on Mars or resource-mining an asteroid are definitely important goals in their own right, only the Moon holds such direct references to Earth. It’s like an orbiting index to the ongoing story of our planet — all we have to do is make the connections.
Learn more about lunar research at the LPI site here, and see the latest news and images from LRO here.
Once again, the Slooh Space Camera team will host a live webcast of an asteroid flyby of Earth. This one might be a bit more intriguing than others, if only because of the connotation this asteroid has. Asteroid Apophis a near-Earth asteroid with an estimated diameter of almost three football fields (270m), is making its closest approach to us this year — but it will still be quite distant, at about 14 million km – but this is close enough for astronomers to study the space rock and assess its future risk.
On Wednesday, January 9th, Slooh.com, will start the webcast at 4 p.m. PST / 7 p.m. EST / 00:00 UTC (1/10) — International times here — accompanied by real-time discussions with Slooh President Patrick Paolucci, Slooh Outreach Coordinator and Engineer Paul Cox, and Documentary Filmmaker Duncan Copp.
This image, obtained during the late commissioning phase of the GeMS adaptive optics system, with the Gemini South AO Imager (GSAOI) on the night of December 28, 2012, reveals exquisite details in the outskirts of the Orion Nebula. Gemini Observatory/AURA
This is the part of the Orion nebula. Recognize it? You may not, as this stunning new image comes from the Gemini Observatory’s recently-commissioned advanced adaptive optics (AO) system named GeMS. It shows clumps of gas ejected from deep within the Orion Nebula which are nicknamed ‘Orion Bullets.’
“The combination of a constellation of five laser guide stars with multiple deformable mirrors allows us to expand significantly on what has previously been possible using adaptive optics in astronomy,” said Benoit Neichel, who currently leads this adaptive optics program for Gemini. “For years our team has focused on developing this system, and to see this magnificent image, just hinting at its scientific potential, made our nights on the mountain – while most folks were celebrating the New Year’s holiday – the best celebration ever!”
The team took the image on December 28, 2012.
About five years ago, astronomers took an image of the Orion Bullets using a previous version of adaptive optics called Altair. Gemini’s instrument scientist for Altair, Chad Trujillo, pointed out that in one shot GeMS covers a significantly larger field-of-view than Altair and a higher quality image.
“The uniformity and performance across the image is amazing! In this new image, the pixels are 2.5 times finer and there are about 16 times more of them,” he said. Both the correction quality and the field-of-view are considerably better than the previous generation of AO systems.”
Detailed views of the Orion Bullet region. In each image pair, left is the Altair 2007 image and right is the new 2012 GeMS image. Credit: Gemini Observatory/AURA
The background stars in the image are part of the Small Magellanic Cloud, which was in the distance behind 47 Tucanae when this image was taken.
