Monday, December 22, 2014

The Milky Way’s New Neighbor May Tell Us Things About the Universe

The Milky Way’s New Neighbor May Tell Us Things About the Universe:



This dwarf spheroidal galaxy in the constellation Fornax is a satellite of our Milky Way and is one of 10 used in Fermi's dark matter search. The motions of the galaxy's stars indicate that it is embedded in a massive halo of matter that cannot be seen. Credit: ESO/Digital Sky Survey 2


Dwarf spheroidal galaxies, like this one seen in the constellation Fornax, may exist in greater numbers than previously thought. Credit: ESO/Digital Sky Survey 2
As part of the Local Group, a collection of 54 galaxies and dwarf galaxies that measures 10 million light years in diameter, the Milky Way has no shortage of neighbors. However, refinements made in the field of astronomy in recent years are leading to the observation of neighbors that were previously unseen. This, in turn, is changing our view of the local universe to one where things are a lot more crowded.

For instance, scientists working out of the Special Astrophysical Observatory in Karachai-Cherkessia, Russia, recently found a previously undetected dwarf galaxy that exists 7 million light years away. The discovery of this galaxy, named KKs3, and those like it is an exciting prospect for scientists, since they can tell us much about how stars are born in our universe.The Russian team, led by Prof Igor Karachentsev of the Special Astrophysical Observatory (SAO), used the Hubble Space Telescope Advanced Camera for Surveys (ACS) to locate KKs3 in the southern sky near the constellation of Hydrus. The discovery occurred back in August 2014, when they finalized their observations a series of stars that have only one ten-thousandth the mass of the Milky Way.

Such dwarf galaxies are far more difficult to detect than others due to a number of distinct characteristics. KKs3 is what is known as a dwarf spheroid (or dSph) galaxy, a type that has no spiral arms like the Milky Way and also suffers from an absence of raw materials (like dust and gas). Since they lack the materials to form new stars, they are generally composed of older, fainter stars.

Image of the KKR 25 dwarf spheroid galaxy obtained by the Special Astrophysical Observatory using the HST. Credit: SAO RAS/Hubble
Image of the KKR 25 dwarf spheroid galaxy obtained by the Special Astrophysical Observatory using the HST. Credit: SAO RAS
In addition, these galaxies are typically found in close proximity to much larger galaxies, like Andromeda, which appear to have gobbled up their gas and dust long ago. Being faint in nature, and so close to far more luminous objects, is what makes them so tough to spot by direct observation.

Team member Prof Dimitry Makarov, also of the Special Astrophysical Observatory, described the process: “Finding objects like Kks3 is painstaking work, even with observatories like the Hubble Space Telescope. But with persistence, we’re slowly building up a map of our local neighborhood, which turns out to be less empty than we thought. It may be that are a huge number of dwarf spheroidal galaxies out there, something that would have profound consequences for our ideas about the evolution of the cosmos.”

Painstaking is no exaggeration. Since they are devoid of materials like clouds of gas and dust fields, scientists are forced to spot these galaxies by identifying individual stars. Because of this, only one other isolated dwarf spheroidal has been found in the Local Group: a dSph known as KKR 25, which was also discovered by the Russian research team back in 1999.

But despite the challenges of spotting them, astronomers are eager to find more examples of dSph galaxies. As it stands, it is believed that these isolated spheroids must have been born out of a period of rapid star formation, before the galaxies were stripped of their dust and gas or used them all up.

Studying more of these galaxies can therefore tell us much about the process star formation in our universe. The Russian team expects that the task will become easier in the coming years as the James Webb Space Telescope and the European Extremely Large Telescope begin service.

Much like the Spitzer Space Telescope, these next-generation telescopes are optimized for infrared detection and will therefore prove very useful in picking out faint stars. This, in turn, will also give us a more complete understanding of our universe and all that it holds.

Further Reading: Royal Astronomical Society



About 

Author, freelance writer, educator, Taekwon-Do instructor, and loving hubby, son and Island boy!
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Comet Q2 Lovejoy Set to Ring in the New Year: Reader Images and More

Comet Q2 Lovejoy Set to Ring in the New Year: Reader Images and More:



Credit and Copyright:


A fine capture of Comet Q2 Lovejoy on December 21st from Dunedin, New Zealand. Credit and Copyright: Ian Griffin (@Iangriffin)
Keeping warm? Yesterday marked the start of astronomical winter for the northern hemisphere, meaning long nights and (hopefully) clear, cold skies. But we’ve also got another reason to brave the cold this week, as Comet C/2014 Q2 Lovejoy is set to put on a show for northern hemisphere observers.(...)

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Friday, December 19, 2014

Astrophotos: Views of the Geminid Meteor Shower from Around the World

Astrophotos: Views of the Geminid Meteor Shower from Around the World:



A stunning moment captured as a Geminid meteor over Mt. Fuji is reflected in Lake Saiko on December 14, 2014. Credit and copyright: Yuga Kurita.


A stunning moment captured as a Geminid meteor over Mt. Fuji is reflected in Lake Saiko on December 14, 2014. Credit and copyright: Yuga Kurita.
It’s nice to know that not everyone around the world was plagued by clouds, dense fog, driving rain and snowstorms like we had in Minnesota during this year’s Geminid Meteor Shower (and all that weather was within one 24-hour period!) In fact, some astrophotographers were able to capture some stunning views of the Geminids, like this absolutely gorgeous shot of a meteor over Mt. Fuji in Japan.

“I’ve captured Fuji with meteors many times in the past,” said photographer Yuga Kurita. “So I went ambitious this time. I tried to capture Fuji and a meteor reflected in Lake Saiko with a standard focal length lens. When I saw this meteor, I was absolutely stunned.”

See more Geminids from around the world, below:




Geminid meteors over Beijing, China. A stacked image of more than 20 meteors, taken in just 140 minutes. Credit and copyright: Steed Yu.


Geminid meteors over Beijing, China. A stacked image of more than 20 meteors, taken in just 140 minutes. Credit and copyright: Steed Yu.


Geminid Meteor on 12-15-2014 .Captured cutting through the winter Milkyway in the constellation of Auriga, you can see the very colorful trail of the meteor in this image, the trail stretched more than 15 degrees of sky. Taken near Warrenton, Virginia. Credit and copyright: John Chumack.


Geminid Meteor on 12-15-2014 .Captured cutting through the winter Milkyway in the constellation of Auriga, you can see the very colorful trail of the meteor in this image, the trail stretched more than 15 degrees of sky. Taken near Warrenton, Virginia. Credit and copyright: John Chumack.


Four different Geminid meteors as seen from Oxfordshire, England with a Canon 1100D with standard lens. The time of the meteor is marked on the photo. Credit and copyright: Mary Spicer.


Four different Geminid meteors as seen from Oxfordshire, England with a Canon 1100D with standard lens. The time of the meteor is marked on the photo. Credit and copyright: Mary Spicer.
Astrophotographer Mary Spicer shared these four meteor shots, and added, “Over about 90 minutes we saw a total of 61 meteors, 57 of which were Geminids and 6 were fireballs.”



In a 3.5 hour period on Dec. 13/14, 2014, the photographer managed to capture 38 Geminid meteors. This composite contains just 11 of those meteors. Credit and copyright: Paul Andrew.


In a 3.5 hour period on Dec. 13/14, 2014, the photographer managed to capture 38 Geminid meteors. This composite contains just 11 of those meteors. Credit and copyright: Paul Andrew.
A timelapse movie taken by Michael Mauldin of the clouds and stars over Liberty Hill, Texas on Saturday, December 13, 2014. Two Geminid meteors are captured (each frame is frozen for a few seconds so you can see them):





Geminid meteors caught over Connaught Dome, at the Norman Lockyer Observatory in Devon, England. Credit and copyright: David Strange.


Geminid meteors caught over Connaught Dome, at the Norman Lockyer Observatory in Devon, England. Credit and copyright: David Strange.


Two Geminid meteors — one especially bright — streak through the sky on Sunday, December 14, 2014. This photo is a composite of two separate frames, taken a few minutes apart, to capture both meteors. Credit and copyright: David Murr.


Two Geminid meteors — one especially bright — streak through the sky on Sunday, December 14, 2014. This photo is a composite of two separate frames, taken a few minutes apart, to capture both meteors. Credit and copyright: David Murr.


A Geminid fireball captured on Dec. 13, 2014 near Cabo Rojo, Puerto Rico. Credit and copyright: Frankie Lucena.


A Geminid fireball captured on Dec. 13, 2014 near Cabo Rojo, Puerto Rico. Credit and copyright: Frankie Lucena.


A faint green Geminid meteor joined in the sky scene with On display are : M44, Jupiter , the Moon, and Procyon in Canis Minor. Credit and copyright: Carsten Pauer.


A faint green Geminid meteor joined in the sky scene with On display are : M44, Jupiter , the Moon, and Procyon in Canis Minor. Credit and copyright: Carsten Pauer.


A unique view of the 2014 Geminid Meteor Shower, taken on Dec. 14. 5 images stacked. Credit and copyright: Jason Asplin.


A unique view of the 2014 Geminid Meteor Shower, taken on Dec. 14. 5 images stacked. Credit and copyright: Jason Asplin.


A Geminid Meteor taken on Dec. 14, 2014 from a garden in the middle of Worthing, West Sussex England. Credit and copyright: BiteYourBum.com Photography.


A Geminid Meteor
taken on Dec. 14, 2014 from a garden in the middle of Worthing, West Sussex England. Credit and copyright: BiteYourBum.com Photography.


A bright Geminid meteor on Dec. 14, 2014. Credit and copyright: Slave Stojanoski.


A bright Geminid meteor on Dec. 14, 2014. Credit and copyright: Slave Stojanoski.


Waiting for Geminids: a self portrait of the photographer waiting for the meteor shower to peak. Credit and copyright: Sergio Garcia Rill.


Waiting for Geminids: a self portrait of the photographer waiting for the meteor shower to peak. Credit and copyright: Sergio Garcia Rill.
While the above photo doesn’t have any meteors, it still garners a place in this post because astrophotographer Sergio Garcia Rill was waiting and hoping to capture some. Alas, writes Rill on Flickr, “While I had good enough luck to get some relatively clear skies for the Geminids meteor shower I think I wasn’t fortunate enough to catch any meteors on camera. I saw about a dozen meteors with my eyes, and a couple in the direction my cameras were pointing, but they probably weren’t strong enough to get captured with the settings I had.”

Posted by Nelio Inacio at 6:59 AM 0 comments

Gallery: Saturn Moons Show How Not To Be Seen In Cassini Images

Gallery: Saturn Moons Show How Not To Be Seen In Cassini Images:



Tethys is mostly obscured behind Rhea as the moons orbit Saturn. The picture was captured by the Cassini spacecraft in April 2012 and highlighted in December 2014. Credit: NASA/JPL-Caltech/Space Science Institute


Tethys is mostly obscured behind Rhea as the moons orbit Saturn. The picture was captured by the Cassini spacecraft in April 2012 and highlighted in December 2014. Credit: NASA/JPL-Caltech/Space Science Institute
Peekaboo! Tethys makes a (mostly in vain) attempt to hide behind Rhea in this picture taken by the Cassini spacecraft a couple of years ago, but highlighted by NASA in a recent picture essay. Besides the neat view of the orbital dance, one thing that is clearly visible between the two moons is the different colors — a product of their different surfaces. It turns out that Tethys’ bright surface is due to geysers from another moon.

“Scientists believe that Tethys’ surprisingly high albedo is due to the water ice jets emerging from its neighbor, Enceladus,” NASA stated. “The fresh water ice becomes the E ring [of Saturn] and can eventually arrive at Tethys, giving it a fresh surface layer of clean ice.”

Saturn has an astounding number of moons — 62 moons discovered so far, and 53 of them named, if you don’t count the spectacular ring that surrounds the planet. The collection of celestial bodies includes Titan, the second-biggest moon in the Solar System. It’s so big that it includes a thick atmosphere. (Ganymede, around Jupiter, is the biggest.)

Below are some other pictures of moons dancing around Saturn — some harder to spot than others. All images were taken by the Cassini spacecraft since it arrived at the planet in 2004.



Titan peeks from behind two of Saturn's rings. Another small moon Epimetheus, appears just above the rings. Credit: NASA/JPL/Space Science Institute


Titan peeks from behind two of Saturn’s rings. Another small moon Epimetheus, appears just above the rings. Credit: NASA/JPL/Space Science Institute


Saturn's moons Dione and Rhea appear conjoined in this optical illusion-like image taken by the Cassini spacecraft. Credit: NASA/JPL/Space Science Institute


Saturn’s moons Dione and Rhea appear conjoined in this optical illusion-like image taken by the Cassini spacecraft. Credit: NASA/JPL/Space Science Institute


Saturn's rings, made dark in part as the planet casts its shadow across them, cut a striking figure before Saturn's largest moon, Titan. Credit: NASA/JPL/Space Science Institute


Saturn’s rings, made dark in part as the planet casts its shadow across them, cut a striking figure before Saturn’s largest moon, Titan. Credit: NASA/JPL/Space Science Institute


Three of Saturn's moons bunch together in this image by Cassini. Credit: NASA/JPL/Space Science Institute. Click for larger image.


Three of Saturn’s moons bunch together in this image by Cassini. Credit: NASA/JPL/Space Science Institute. Click for larger image.


Saturns rings with Saturns moon Mimas in the foreground (credit: NASA)


Saturn’s rings with Saturn’s moon Mimas in the foreground (credit: NASA)


Titan and Tethys line up for a portrait of 'sibling' moons. Credit: NASA/JPL/Space Science Institute


Titan and Tethys line up for a portrait of ‘sibling’ moons. Credit: NASA/JPL/Space Science Institute


About 

Elizabeth Howell is the senior writer at Universe Today. She also works for Space.com, Space Exploration Network, the NASA Lunar Science Institute, NASA Astrobiology Magazine and LiveScience, among others. Career highlights include watching three shuttle launches, and going on a two-week simulated Mars expedition in rural Utah. You can follow her on Twitter @howellspace or contact her at her website.
Posted by Nelio Inacio at 6:52 AM 0 comments

Morning Star, We Hardly Knew Ya: Venus Express’ Best Discoveries In 8 Years

Morning Star, We Hardly Knew Ya: Venus Express’ Best Discoveries In 8 Years:



Artist's impression of Venus Express entering orbit in 2006. Credit: ESA - AOES Medialab


Artist’s impression of Venus Express entering orbit in 2006. Credit: ESA – AOES Medialab
Venus Express is mostly dead. The spacecraft spent more than eight years faithfully relaying information from the Morning Star/Evening Star planet, but it’s now out of fuel, out of control and within weeks of burning up in the atmosphere.

While we mourn the end of the productive mission, the European Space Agency spacecraft showed us a lot about the planet that we once considered a twin to Earth. Some of the surprises, as you can see below, including a possibly slowing-down rotation, and the realization that volcanoes may still be active on the hellish planet.



False colour composite of a rainbow-like feature known as a ‘glory’, seen on Venus on 24 July 2011. The image is composed of three images at ultraviolet, visible, and near-infrared wavelengths from the Venus Monitoring Camera. The images were taken 10 seconds apart and, due to the motion of the spacecraft, do not overlap perfectly. The glory is 1200 km across, as seen from the spacecraft, 6000 km away. It's the only glory ever seen on another planet. Credit: ESA/MPS/DLR/IDA.


False color composite of a rainbow-like feature known as a ‘glory’, seen on Venus on 24 July 2011. The image is composed of three images at ultraviolet, visible, and near-infrared wavelengths from the Venus Monitoring Camera. The images were taken 10 seconds apart and, due to the motion of the spacecraft, do not overlap perfectly. The glory is 1200 km across, as seen from the spacecraft, 6000 km away. It’s the only glory ever seen on another planet. Credit: ESA/MPS/DLR/IDA.


Quick video summary: Venus Express found that the spacecraft’s rotation may have slowed down by 6.5 minutes between 1996 (when the Magellan spacecraft was in orbit) and 2012. The surprising information emerged when scientists discovered surface features weren’t in the expected areas, and couldn’t find any calculation errors between the data.



Animation of Venus’ southern polar vortex made from VIRTIS thermal infrared images; white is cooler clouds at higher altitudes. Credit: ESA/VIRTIS-VenusX/INAF-IASF/LESIA-Obs. de Paris (G. Piccioni, INAF-IASF)


Quick video summary: Volcanic flows may still be active on Venus’ surface, according to 2010 data from the mission. Scientists looked at surface areas that had not been “weathered” very much (indicating that they are relatively young) and detected at least nine spots where the heat in those zones is much higher than the areas around it.



Venus Express picture of clouds on the planet. Despite the planet being extremely hot, the spacecraft found a cold layer in the atmosphere at temperatures of about -175 degrees Celsius (-283 Fahrenheit) that is colder than anything on Earth. It's so chilling that carbon dioxide may freeze and fall as snow or ice. Credit: ESA/MPS/DLR/IDA


A picture of Venus’ clouds. Despite the planet being extremely hot, Venus Express found a cold layer in the atmosphere at temperatures of about -175 degrees Celsius (-283 Fahrenheit) that is colder than anything on Earth. It’s so chilling that carbon dioxide may freeze and fall as snow or ice. Credit: ESA/MPS/DLR/IDA


Artist's impression of Venus with the solar wind flowing around the planet, which has little magnetic protection. Venus Express found that a lot of water has bled into space over the years from the planet, which happens when the sun's ultraviolet radiation breaks oxygen and hydrogen molecules apart and pushes them into space. Credit: ESA - C. Carreau


Artist’s impression of Venus with the solar wind flowing around the planet, which has little magnetic protection. Venus Express found that a lot of water has bled into space over the years from the planet, which happens when the sun’s ultraviolet radiation breaks oxygen and hydrogen molecules apart and pushes them into space. Credit: ESA – C. Carreau


About 

Elizabeth Howell is the senior writer at Universe Today. She also works for Space.com, Space Exploration Network, the NASA Lunar Science Institute, NASA Astrobiology Magazine and LiveScience, among others. Career highlights include watching three shuttle launches, and going on a two-week simulated Mars expedition in rural Utah. You can follow her on Twitter @howellspace or contact her at her website.
Posted by Nelio Inacio at 6:51 AM 0 comments

The Universe’s Tour Guide

The Universe’s Tour Guide:



Satellites swarm around the Earth on the Hayden Planetarium's dome. Credit: AMNH.


Satellites swarm around the Earth on the Hayden Planetarium’s dome. Credit: AMNH.
The hazy, white horizon lifts away slowly, giving way to the blue and green, cloud-swept marble we call home. I take in a deep breath, astonished by the Earth’s staggering beauty in stark contrast to the sprinkled backdrop.

People are still shuffling into the 429-seat Hayden Planetarium at the American Museum of Natural History, their shadows projected onto the arched ceiling. A voice resonates in the dome’s spacious cavity. Brian Abbott, the planetarium’s assistant director, is welcoming everyone to the show. It’s a “highlights tour,” he says, covering most of the known universe in one fell swoop.

As we leave Earth further behind, the satellites appear, swarming above our planet like bees around a hive. Soon the curved orbits of other planets become visible and we fly toward Mars.

In minutes we are hovering above Valles Marineris, a canyon so massive it would stretch from Manhattan to Los Angeles. The projectors display six-meter resolution data from the Mars Global Surveyor. We see the canyon ridges in such incredible, 3D detail it seems we could reach out and touch the tallest peaks with our fingers.

Abbott’s voice is slow and soothing. He speaks with authority, mindful of every inflection he makes and every word he uses. He carefully constructs his sentences, but also takes the time to crack a few jokes along the way. It’s just another day at the office, and yet it sounds like he’s having the time of his life.



Abbott in his office at AMNH. Credit: Shannon Hall


Abbott in his office at AMNH. Credit: Shannon Hall
Abbott never dreamed of becoming an astronomer. In high school he was on a very different path, headed toward a career in art. Then, in 1985, Halley’s comet was scheduled to appear in the night sky. “For some reason I needed to find it,” he said. So, from his backyard outside Philadelphia, he learned how to pinpoint the constellations and spot distant objects, like galaxies, nebulae and star clusters. When the comet finally came, he was able to spot it, a tiny target in the vast sky. It was a revelation that pumped him full of adrenalin on that long, dark night.

Yet while Abbott left art as a career choice behind, he has been able to integrate art with astronomy, as his planetarium show demonstrates. “I admire the niche he has created for himself in the intersection between art, visualization and science,” said colleague Jana Grcevich, a postdoctoral researcher at AMNH.

Just before starting work at the museum in 1999, however, Abbott was an unhappy graduate student in the astronomy department at the University of Toledo. “Who can explain what gets you out of bed in the morning,” he said. “It just wasn’t what moved me.” Frustrated with his lot in life, he had plans to drive his car across the country, Jack Kerouac style. But first, he attended one last meeting: the American Astronomical Society’s annual conference in Chicago.

There, among all the job listings, he saw only one that wasn’t a research or a faculty position. The AMNH needed someone to create the world’s first interactive atlas of the Universe. So Abbott started sniffing around and coincidentally ran into the planetarium’s famed director, Neil DeGrasse Tyson, in the hallway of their hotel. Yet “Neil wasn’t Neil back then,” Abbott recalled. “He was somewhat known but he wasn’t mobbed with people.”

The duo started talking, and in two weeks Abbott found himself living in New York City with a new job. But he doesn’t regret it for a second. “I feel like I’m almost divorced from the night sky living here. I’m not able to just go out in my backyard and set up a telescope and see stuff. But we have this great dome. And I can go in there and see the entire Universe far better than I can see in the night sky.”

Now, Abbott spends his days visualizing large data sets. For the past 14 years, he has been creating a three-dimensional map of the Universe. He’s constantly updating the atlas with recent data hot off the world’s biggest telescopes and best satellites. And in the planetarium, he turns this abstract data into the planets, stars and galaxies that visitors flock to see. “What we want to do is focus on the scientific story of the universe,” said Abbott. “And we want that reflected in our dome.”

As the Hayden Planetarium’s popularity suggests, there’s a surprising public appetite for such strict scientific cartography. “There’s always at least one time in the show when the air comes out of the room,” said Abbott, referring to the moment when the audience takes a collective breath, in awe of the universe above them.

I can recall easily when that moment came for me. We had just left the Milky Way galaxy. Looking back on our home galaxy, the bright yellow core was surrounded by gorgeous blue spiral arms and sweeping dust lanes. Swarms of smaller galaxies began to appear. In minutes, we saw the Tully Catalogue, which covers an astonishing 30,000 galaxies in total.

The audience gasped in awe at the sheer number of galaxies in our local neighborhood. It’s impossible not to feel small at a moment like that.

But we were nowhere near the farthest reaches of the Universe yet. In moments, we saw the total number of galaxies ever recorded in the Sloan Digital Sky Survey. A chill ran down my spine. There were over one million galaxies projected onto the dome. Each one has over 100 billion stars. And each one of those likely has 5 or even ten planets. There are so many opportunities for life in our vast Universe.

We continued to zoom out, until we reached the edges of the 46.6 billion-light-year-wide observable Universe. In just over an hour, the tour had grossly violated the speed of light. “So that’s the Universe,” Abbott said. “Any questions?”



About 

Shannon Hall is a freelance science journalist. She holds two B.A.'s from Whitman College in physics-astronomy and philosophy, and an M.S. in astronomy from the University of Wyoming. Currently, she is working toward a second M.S. from NYU's Science, Health and Environmental Reporting program. You can follow her on Twitter @ShannonWHall.
Posted by Nelio Inacio at 6:50 AM 0 comments

Comet Finlay in Bright Outburst, Visible in Small Telescopes

Comet Finlay in Bright Outburst, Visible in Small Telescopes:



Comet Finlay on December 16th showing a bright coma and short tail. Credit: FRAM team


Comet Finlay on December 16th shows a bright coma and short tail. Its sudden rise  to 9th magnitude was confirmed on December 18th by Australian comet observer Paul Camilleri. The moderately condensed object is about 3 arc minutes in diameter. Credit: J. Cerny, M. Masek, K. Honkova, J. Jurysek, J. Ebr, P. Kubanek, M. Prouza, M. Jelinek
Short-period comet 15P/Finlay, which had been plunking along at a dim magnitude +11, has suddenly brightened in the past couple days to +8.7, bright enough to see in 10×50 or larger binoculars. Czech comet observer Jakub Cerny and his team photographed the comet on December 16th and discovered the sudden surge. Wonderful news!

While comets generally brighten as they approach the Sun and fade as they depart, any one of them can undergo a sudden outburst in brightness. You can find Finlay right now low in the southwestern sky at nightfall near the planet Mars. While outbursts are common, astronomers still aren’t certain what causes them. It’s thought that sub-surface ices, warmed by the comet’s approach to the Sun, expand until the pressure becomes so great they shatter the ice above, sending large fragments flying and exposing fresh new ice. Sunlight gets to work vaporizing both the newly exposed vents and aerial shrapnel. Large quantities of dust trapped in the ice are released and glow brightly in the Sun’s light, causing the comet to quickly brighten.

Some comets flare up dramatically. Take 29P/Schwassmann-Wachmann. Normally a dim bulb at 17th magnitude, once or twice a year it flares to magnitude 12 and occasionally 10!



Animated movie showing the expansion of the coma of Comet Holmes over 9 nights during its spectacular outburst in November. Credit: 3.6-meter Canada-France-Hawaii telescope on Mauna Kea / David Jewitt


Animated movie showing the expansion of the coma of Comet Holmes over 9 nights during its spectacular outburst in November 2007. Credit: 3.6-meter Canada-France-Hawaii telescope on Mauna Kea / David Jewitt
Whatever the reason, outbursts can last from days to weeks. It’s anybody’s guess how long 15P/Finlay will remain a relatively easy target for comet hungry skywatchers.  While not high in the sky, especially from the northern U.S., it can be seen during early evening hours if you plan well.



By pure good chance, Comet Finlay will track with Mars through December into early January. They'll make a remarkably close pair on the evening of December 23rd. This map shows the nightly position of the comet from Dec. 18th through Jan. 12th. Mars location is shown every 5 nights. Positions plotted for 6:15 p.m. (CST) 1 hour and 45 minutes after sunset. Stars shown to magnitude 8. Star magnitudes are underlined. Click to enlarge and print. Source: Chris Marriott's SkyMap software


By good luck, Comet Finlay will track with Mars through December into early January. On December 23rd, they’ll come together in a remarkably close conjunction. This map shows the nightly position of the comet from Dec. 18th through Jan. 12th. Mars’ location is shown every 5 nights. Positions plotted for 6:15 p.m. (CST) 1 hour and 45 minutes after sunset. Stars shown to magnitude 8. Star magnitudes are underlined. Click to enlarge and print for outside use. Source: Chris Marriott’s SkyMap software
Comet Finlay was discovered by William Henry Finlay from South Africa on September 26, 1886. It reaches perihelion or closest approach to the Sun on December 27th and was expected to brighten to magnitude +10 when nearest Earth in mid-January at 130 million miles (209 million km). Various encounters with Jupiter since discovery have increased its original period of 4.3 years to the current 6.5 years and shrunk its perihelion distance from 101 million to 90 million miles.



Comet Finlay appears considerably fainter in this pre-outburst photo taken on December 14th. Credit: Alfons Diepvens


Comet Finlay appears considerably fainter in this pre-outburst photo taken on December 14th. Credit: Alfons Diepvens
Looking at the map above it’s amazing how closely the comet’s path parallels that of Mars this month. Unlike Comet Siding Spring’s encounter with that planet last October, Finlay’s proximity is line of sight only. Still, it’s nice to have a fairly bright planet nearby to point the way to our target. Mars and Finlay’s paths intersect on December 23rd, when the duo will be in close conjunction only about 10? apart (1/3 the diameter of the Full Moon) for observers in the Americas. They’ll continue to remain almost as close on Christmas Eve. Along with Comet Q2 Lovejoy, this holiday season is turning out to be a joyous occasion for celestial fuzzballs!

To give you a little context to make finding Comet FInlay easier, use this wide-view map. A line from bright Vega in the western sky left through Altair will take you directly to Mars and the comet. This map shows the sky at nightfall tonight when the comet will be about 15 degrees high in the southwestern sky. Source: Stellarium
To give you a little context to make finding Comet FInlay easier, use this wide-view map. A line from bright Vega in the western sky left through Altair will take you directly to Mars and the comet. This map shows the sky at nightfall tonight when the comet will be about 15° high in the southwestern sky. Source: Stellarium


About 

I'm a long-time amateur astronomer and member of the American Association of Variable Star Observers (AAVSO). My observing passions include everything from auroras to Z Cam stars. Every day the universe offers up something both beautiful and thought-provoking. I also write a daily astronomy blog called Astro Bob.
Posted by Nelio Inacio at 6:49 AM 0 comments

Kepler ‘K2′ Finds First Exoplanet, A ‘Super-Earth’, While Surfing Sun’s Pressure Wave For Control

Kepler ‘K2′ Finds First Exoplanet, A ‘Super-Earth’, While Surfing Sun’s Pressure Wave For Control:



Artist's conception of the Kepler Space Telescope. Credit: NASA/JPL-Caltech


Artist’s conception of the Kepler Space Telescope. Credit: NASA/JPL-Caltech
It’s alive! NASA’s Kepler space telescope had to stop planet-hunting during Earth’s northern-hemisphere summer 2013 when a second of its four pointing devices (reaction wheels) failed. But using a new technique that takes advantage of the solar wind, Kepler has found its first exoplanet since the K2 mission was publicly proposed in November 2013.

And despite a loss of pointing precision, Kepler’s find was a smaller planet — a super-Earth! It’s likely a water world or a rocky core shrouded in a thick, Neptune-like atmosphere. Called HIP 116454b, it’s 2.5 times the size of Earth and a whopping 12 times the mass. It circles its dwarf star quickly, every 9.1 days, and is about 180 light-years from Earth.


“Like a phoenix rising from the ashes, Kepler has been reborn and is continuing to make discoveries. Even better, the planet it found is ripe for follow-up studies,” stated lead author Andrew Vanderburg of the Harvard-Smithsonian Center for Astrophysics.

Kepler ferrets out exoplanets from their parent stars while watching for transits — when a world passes across the face of its parent sun. This is easiest to find on huge planets that are orbiting dim stars, such as red dwarfs. The smaller the planet and/or brighter the star, the more difficult it is to view the tiny shadow.



Infographic showing how the Kepler space telescope continued searching for planets despite two busted reaction wheels. Credit: NASA Ames/W Stenzel


Infographic showing how the Kepler space telescope continued searching for planets despite two busted reaction wheels. Credit: NASA Ames/W Stenzel
The telescope needs at least three reaction wheels to point consistently in space, which it did for four years, gazing at the Cygnus constellation. (And there’s still a lot of data to come from that mission, including the follow-up to a bonanza where Kepler detected hundreds of new exoplanets using a new technique for multiple-planet systems.)

But now, Kepler needs an extra hand to do so. Without a mechanic handy to send out to telescope’s orbit around the Sun, scientists decided instead to use sunlight pressure as a sort of “virtual” reaction wheel. The K2 mission underwent several tests and was approved budgetarily in May, through 2016.

The drawback is Kepler needs to change positions every 83 days since the Sun eventually gets in the telescope’s viewfinder; also, there are losses in precision compared to the original mission. The benefit is it can also observe objects such as supernovae and star clusters.



Kepler-62f, an exoplanet that is about 40% larger than Earth. It's located about 1,200 light-years from our solar system in the constellation Lyra. Credit: NASA/Ames/JPL-Caltech


Kepler-62f, an exoplanet that is about 40% larger than Earth. It’s located about 1,200 light-years from our solar system in the constellation Lyra. Credit: NASA/Ames/JPL-Caltech
“Due to Kepler’s reduced pointing capabilities, extracting useful data requires sophisticated computer analysis,” CFA added in a statement. “Vanderburg and his colleagues developed specialized software to correct for spacecraft movements, achieving about half the photometric precision of the original Kepler mission.”

That said, the first nine-day test with K2 yielded one planetary transit that was confirmed with measurements of the star’s “wobble” as the planet tugged on it, using the HARPS-North spectrograph on the Telescopio Nazionale Galileo in the Canary Islands. A small Canadian satellite called MOST (Microvariability and Oscillations of STars) also found transits, albeit weakly.

A paper based on the research will appear in the Astrophysical Journal.



About 

Elizabeth Howell is the senior writer at Universe Today. She also works for Space.com, Space Exploration Network, the NASA Lunar Science Institute, NASA Astrobiology Magazine and LiveScience, among others. Career highlights include watching three shuttle launches, and going on a two-week simulated Mars expedition in rural Utah. You can follow her on Twitter @howellspace or contact her at her website.
Posted by Nelio Inacio at 6:44 AM 0 comments

Chandra Weighs Most Massive Galaxy Cluster in Distant Universe

Chandra Weighs Most Massive Galaxy Cluster in Distant Universe:



il Gioiello Cluster


A newly discovered galaxy cluster is the most massive one ever detected with an age of 800 million years or younger. Using data from NASA's Chandra X-ray Observatory, astronomers have accurately determined the mass and other properties of this cluster, as described in our latest press release. This is an important step in understanding how galaxy clusters, the largest structures in the Universe held together by gravity, have evolved over time.

A composite image shows the distant and massive galaxy cluster that is officially known as XDCP J0044.0-2033. Researchers, however, have nicknamed it "Gioiello", which is Italian for "jewel". They chose this name because an image of the cluster contains many sparkling colors from the hot, X-ray emitting gas and various star-forming galaxies within the cluster. Also, the research team met to discuss the Chandra data for the first time at Villa il Gioiello, a 15th century villa near the Observatory of Arcetri, which was the last residence of prominent Italian astronomer Galileo Galilei. In this new image of the Gioiello Cluster, X-rays from Chandra are purple, infrared data from ESA's Hershel Space Telescope appear as large red halos around some galaxies, and optical data from the Subaru telescope on Mauna Kea in Hawaii are red, green, and blue.

Astronomers first detected the Gioiello Cluster, located about 9.6 billion light years away, using ESA's XMM-Newton observatory. They were then approved to study the cluster with Chandra in observations that were equivalent to over four days of time. This is the deepest X-ray observation yet made on a cluster beyond a distance of about 8 billion light years.

The long observing time allowed the researchers to gather enough X-ray data from Chandra that, when combined with scientific models, provides an accurate weight of the cluster. They determined that the Gioiello Cluster contains a whopping 400 trillion times the mass of the Sun.

More information at http://chandra.harvard.edu/photo/2014/xdcp004/index.html

-Megan Watzke, CXC
Posted by Nelio Inacio at 6:43 AM 0 comments

Wednesday, December 17, 2014

Just in Time for the Holidays – Galactic Encounter Puts on Stunning Display

Just in Time for the Holidays – Galactic Encounter Puts on Stunning Display:



That's the case with NGC 2207 and IC 2163, which are located about 130 million light-years from Earth, in the constellation of Canis Major. Image credit: NASA/CXC/SAO/STScI/JPL-Caltech


The merging galaxies of NGC 2207 and IC 2163, as observed by Chandra, Hubble and Spitzer. Image credit: NASA/CXC/SAO/STScI/JPL-Caltech
At this time of year, festive displays of light are to be expected. This tradition has clearly not been lost on the galaxies NHC 2207 and IC 2163. Just in time for the holidays, these colliding galaxies, which are located within the Canis Major constellation (some 130 million light-years from Earth,) were seen putting on a spectacular lights display for us folks here on Earth!

And while this galaxy has been known to produce a lot of intense light over the years, the image above is especially luminous. A composite using data from the Chandra Observatory and the Hubble and Spitzer Space Telescopes, it shows the combination of visible, x-ray, and infrared light coming from the galactic pair.

In the past fifteen years, NGC 2207 and IC 2163 have hosted three supernova explosions and produced one of the largest collections of super bright X-ray lights in the known universe. These special objects – known as “ultraluminous X-ray sources” (ULXs) – have been found using data from NASA’s Chandra X-ray Observatory.

While the true nature of ULXs is still being debated, it is believed that they are a peculiar type of star X-ray binary. These consist of a star in a tight orbit around either a neutron star or a black hole. The strong gravity of the neutron star or black hole pulls matter from the companion star, and as this matter falls toward the neutron star or black hole, it is heated to millions of degrees and generates X-rays.



the core of galaxy Messier 82 (M82), where two ultraluminous X-ray sources, or ULXs, reside (X-1 and X-2). Credit: NASA


The core of galaxy Messier 82 (M82), where two ultraluminous X-ray sources, or ULXs, reside (X-1 and X-2). Credit: NASA
Data obtained from Chandra has determined that – much like the Milky Way Galaxy – NGC 2207 and IC 2163 are sprinkled with many star X-ray binaries. In the new Chandra image, this x-ray data is shown in pink, which shows the sheer prevalence of x-ray sources within both galaxies.

Meanwhile, optical light data from the Hubble Space Telescope is rendered in red, green, and blue (also appearing as blue, white, orange, and brown due to color combinations,) and infrared data from the Spitzer Space Telescope is shown in red.

The Chandra observatory spent far more time observing these galaxies than any previous ULX study, roughly five times as much. As a result, the study team – which consisted of researchers from Harvard University, MIT, and Sam Houston State University – were able to confirm the existence of 28 ULXs between NGC 2207 and IC 2163, seven of which had never before been seen.

In addition, the Chandra data allowed the team of scientists to observe the correlation between X-ray sources in different regions of the galaxy and the rate at which stars are forming in those same regions.



Galaxy mergers, such as the Mice Galaxies will be part of Galaxy Zoo's newest project. Credit: Hubble Space Telescope


The Mice galaxies, seen here well into the process of merging. Credit: Hubble Space Telescope
As the new Chandra image shows, the spiral arms of the galaxies – where large amounts of star formation is known to be occurring – show the heaviest concentrations of ULXs, optical light, and infrared. This correlation also suggests that the companion star in the star X-ray binaries is young and massive.

This in turn presents another possibility which has to do with star formation during galactic mergers. When galaxies come together, they produce shock waves that cause clouds of gas within them to collapse, leading to periods of intense star formation and the creation of star clusters.

The fact that the ULXs and the companion stars are young (the researchers estimate that they are only 10 million years old) would seem to confirm that they are the result of NGC 2207 and IC 2163 coming together. This seem a likely explanation since the merger between these two galaxies is still in its infancy, which is attested to by the fact that the galaxies are still separate.

They are expected to collide soon, a process which will make them look more like the Mice Galaxies (pictured above). In about one billion years time, they are expected to finish the process, forming a spiral galaxy that would no doubt resemble our own.

A paper describing the study was recently published on online with The Astrophysical Journal.

Further Reading: NASA/JPL, Chandra, arXiv Astrophysics



About 

Author, freelance writer, educator, Taekwon-Do instructor, and loving hubby, son and Island boy!
Posted by Nelio Inacio at 3:45 AM 0 comments

New Signal May Be Evidence of Dark Matter, Say Researchers

New Signal May Be Evidence of Dark Matter, Say Researchers:



Dark Matter Halo


All galaxies are thought to have a dark matter halo. This simulated image shows the distribution of dark matter surrounding our very own Milky Way. Image credit: J. Diemand, M. Kuhlen and P. Madau (UCSC)
Dark matter is the architect of large-scale cosmic structure and the engine behind proper rotation of galaxies. It’s an indispensable part of the physics of our Universe – and yet scientists still don’t know what it’s made of. The latest data from Planck suggest that the mysterious substance comprises 26.2% of the cosmos, making it nearly five and a half times more prevalent than normal, everyday matter. Now, four European researchers have hinted that they may have a discovery on their hands: a signal in x-ray light that has no known cause, and may be evidence of a long sought-after interaction between particles – namely, the annihilation of dark matter.

When astronomers want to study an object in the night sky, such as a star or galaxy, they begin by analyzing its light across all wavelengths. This allows them to visualize narrow dark lines in the object’s spectrum, called absorption lines. Absorption lines occur because a star’s or galaxy’s component elements soak up light at certain wavelengths, preventing most photons with those energies from reaching Earth. Similarly, interacting particles can also leave emission lines in a star’s or galaxy’s spectrum, bright lines that are created when excess photons are emitted via subatomic processes such as excitement and decay. By looking closely at these emission lines, scientists can usually paint a robust picture of the physics going on elsewhere in the cosmos.

But sometimes, scientists find an emission line that is more puzzling. Earlier this year, researchers at the Laboratory of Particle Physics and Cosmology (LPPC) in Switzerland and Leiden University in the Netherlands identified an excess bump of energy in x-ray light coming from both the Andromeda galaxy and the Perseus star cluster: an emission line with an energy around 3.5keV. No known process can account for this line; however, it is consistent with models of the theoretical sterile neutrino – a particle that many scientists believe is a prime candidate for dark matter.

The researchers believe that this strange emission line could result from the annihilation, or decay, of these dark matter particles, a process that is thought to release x-ray photons. In fact, the signal appeared to be strongest in the most dense regions of Andromeda and Perseus and increasingly more diffuse away from the center, a distribution that is also characteristic of dark matter. Additionally, the signal was absent from the team’s observations of deep, empty space, implying that it is real and not just instrumental artifact.

In a pre-print of their paper, the researchers are careful to stress that the signal itself is weak by scientific standards. That is, they can only be 99.994% sure that it is a true result and not just a rogue statistical fluctuation, a level of confidence that is known as 4σ. (The gold standard for a discovery in science is 5σ: a result that can be declared “true” with 99.9999% confidence) Other scientists are not so sure that dark matter is such a good explanation after all. According to predictions made based on measurements of the Lyman-alpha forest – that is, the spectral pattern of hydrogen absorption and photon emission within very distant, very old gas clouds – any particle purporting to be dark matter should have an energy above 10keV – more than twice the energy of this most recent signal.

As always, the study of cosmology is fraught with mysteries. Whether this particular emission line turns out to be evidence of a sterile neutrino (and thus of dark matter) or not, it does appear to be a signal of some physical process that scientists do not yet understand. If future observations can increase the certainty of this discovery to the 5σ level, astrophysicists will have yet another phenomena to account for – an exciting prospect, regardless of the final result.

The team’s research has been accepted to Physical Review Letters and will be published in an upcoming issue.



About 

Vanessa earned her bachelor's degree in Astronomy and Physics in 2009 from Wheaton College in Massachusetts. Her credits in astronomy include observing and analyzing eclipsing binary star systems and taking a walk on the theory side as a NSF REU intern, investigating the impact of type 1a supernovae on the expansion of the Universe. In her spare time she enjoys writing about astrophysics and cosmology, making delicious vegetarian meals, taking adventures with her husband and/or Nikon D50, and saving the world.
Posted by Nelio Inacio at 3:45 AM 0 comments
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