An artist’s impression of the collision between the Milky Way and Andromeda from Earth. Credit: James Gitlin/STScI.
Billions of years from now, the Milky Way will look totally different, as pictured to the left. When you look up at the sky, you may see another entire galaxy passing through the plane of our own, creating stars and supernovae and changing the entire sky.
Though most galaxies are rushing away from us as the Universe expands, Andromeda and the Milky Way are orbiting each other and closing in fast. Collisions between galaxies aren’t always catastrophic (the Milky Way is colliding with the Canis Major Dwarf galaxy right now, swallowing its stars up into the galactic disk), but they can trigger star formation on large scales and increase the number of supernovae.
When the galaxies collide, there is little chance that many stars will slam into each other directly because they are so spread out; however, the gas that lies between the stars can collide, heat up and trigger the formation of new stars. This interstellar gas and dust could also get sucked up by existing stars, increasing their mass to the point where they go supernova.
By the time the Milky Way and Andromeda collide, though, much of the gas in both galaxies will have been used up to create stars, so a “starburst” won’t happen. It won’t be a quick merger, though, and the spiral structure of each will be seriously changed. As you can see in this animated simulation from University of Toronto astronomer John Dubinski, the galaxies will pass through each other a few times, and the gravitational disturbance of this passage will throw stars willy-nilly into empty space.
Andromeda and the Milky Way will pass through each other once, then fall apart for about a billion years, then pass again, and again until finally settling down to merge completely about 5 billion years from now. The resulting galaxy won’t look anything like either of the merged galaxies – it will be a fuzzy blob called an elliptical galaxy. “Milkomeda” has a nice ring to it, and is one proposed name for the new merged galaxy.
When the galaxies do finally merge, there is a small chance that the Solar System will either join the Andromeda galaxy for a short while during one of the passes, or that it will be flung out of our galactic disk into interstellar space. For an in-depth analysis of this collision and statistics on the chances of the Sun and planets being ejected, check out “The Collision Between The Milky Way and Andromeda” by Harvard-Smithsonian astrophysicists T.J. Cox and Abraham Loeb.
Of course, Andromeda is not the only thing that could collide with the Milky Way. There is currently a large cloud of hydrogen gas on a collision course with the Milky Way and though the edge of the cloud is already interacting with our galaxy, it won’t set off star-forming fireworks until at least 40 million years from now. Named Smith’s Cloud after the astronomer who discovered it in 1963, it is 11,000 light-years long and 2,500 light-years wide, and has enough hydrogen to form a million stars the mass of the Sun. More information about this collision can be found right here on Universe Today, and from the National Radio Astronomy Observatory.
Pamela and Fraser talk about what the Milky Way and Andromeda collision will look like in the September 28th, 2008 episode of Astronomy Cast, and the Milky Way in Episode 99.
Artists concept of a shredded asteroid getting too close to a star. (NASA/JPL-Caltech)
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Astronomers studying white dwarfs have found the remains of “shredded” asteroids around some of these dead stars. This finding suggests that the same materials that make up Earth and our solar system’s other rocky bodies could be common in the universe. If the materials are common, then rocky planets could be, too. “If you ground up our asteroids and rocky planets, you would get the same type of dust we are seeing in these star systems,” said Michael Jura of the University of California, Los Angeles, who presented the results today at the American Astronomical Society meeting in Long Beach, Calif. “This tells us that the stars have asteroids like ours — and therefore could also have rocky planets.” But most surprising, astronomers have been able to use the rocky debris to study the evolution of planets.
Observations with NASA’s Spitzer Space Telescope reveal six dead “white dwarf” stars littered with the remains of shredded asteroids.
Asteroids and planets form out of dusty material that swirls around young stars. The dust sticks together, forming clumps and eventually full-grown planets. Asteroids are the leftover debris. When a star like our sun nears the end of its life, it puffs up into a red giant that consumes its innermost planets, while jostling the orbits of remaining asteroids and outer planets. As the star continues to die, it blows off its outer layers and shrinks down into a skeleton of its former self — a white dwarf.
Sometimes, a jostled asteroid wanders too close to a white dwarf and meets its demise — the gravity of the white dwarf shreds the asteroid to pieces. A similar thing happened to Comet Shoemaker Levy 9 when Jupiter’s gravity tore it up, before the comet ultimately smashed into the planet in 1994.
Spitzer observed shredded asteroid pieces around white dwarfs with its infrared spectrograph, an instrument that breaks light apart into a rainbow of wavelengths, revealing imprints of chemicals. Silicates in Alien Asteroids. Credit: NASA/JPL/Caltech
“While no one yet has the ability to directly see the smashed up debris and measure its composition, we have the tools to measure the potential capacity for planets,” said Jura at today’s press conference.
Spitzer analyzed the asteroid dust around two so-called polluted white dwarfs; the new observations bring the total to eight. Jura said only 1% of white dwarfs observed have broken up asteroids in their vicinity.
“Now, we’ve got a bigger sample of these polluted white dwarfs, so we know these types of events are not extremely rare,” said Jura.
In all eight systems observed, Spitzer found that the dust contains a glassy silicate mineral similar to olivine and commonly found on Earth. “This is one clue that the rocky material around these stars has evolved very much like our own,” said Jura.
The Spitzer data also suggest there is no carbon in the rocky debris — again like the asteroids and rocky planets in our solar system, which have relatively little carbon.
A single asteroid is thought to have broken apart within the last million years or so in each of the eight white-dwarf systems. The biggest of the bunch was once about 200 kilometers (124 miles) in diameter, a bit larger than Los Angeles County.
Jura says the real power of observing these white dwarf systems is still to come. When an asteroid “bites the dust” around a dead star, it breaks into very tiny pieces. Asteroid dust around living stars, by contrast, is made of larger particles. By continuing to use spectrographs to analyze the visible light from this fine dust, astronomers will be able to see exquisite details — including information about what elements are present and in what abundance. This will reveal much more about how other star systems sort and process their planetary materials.
“It’s as if the white dwarfs separate the dust apart for us,” said Jura.
Source: Spitzer Space Telescope, AAS Press Conference
Artist's concept shows young, blue stars encircling a supermassive black hole at the core of a spiral galaxy like the Milky Way.Credit: NASA, ESA, and A. Schaller (for STScI)
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Just as young children need safe, nurturing environments to develop and grow, young stars, too need just the right environment to get their start in life. Or do they? At the center of our galaxy is a 4 million solar-mass black hole. If molecular clouds that form stellar nurseries were nearby, they should be ripped apart by powerful, black-hole-induced gravitational tides. But yet, astronomers have found two young protostars located just a few light-years from the galactic center. Using the Very Large Array of radio telescopes, astronomers from the Harvard-Smithsonian Center for Astrophysics and the Max Planck Institute for Radio Astronomy made this discovery, showing that stars indeed can form close to a black hole. “We literally caught these stars in the act of forming,” said Smithsonian astronomer Elizabeth Humphreys, who presented the finding today at a meeting of the American Astronomical Society in Long Beach, California.
It’s difficult to study the mysterious region near the Milky Way’s center. Visible light can’t penetrate the dominant gas and dust, so astronomers use other wavelengths like infrared and radio to penetrate the dust more easily.
Humphreys and her colleagues searched for water masers—radio signals that serve as signposts for protostars still embedded in their birth cocoons. They found two protostars located seven and 10 light-years from the galactic center. Combined with one previously identified protostar, the three examples show that star formation is taking place near the Milky Way’s core.
Their finding suggests that molecular gas at the center of our galaxy must be denser than previously believed. A higher density would make it easier for a molecular cloud’s self-gravity to overcome tides from the black hole, allowing it to not only hold together but also collapse and form new stars.
The discovery of these protostars corroborates recent theoretical work, in which a supercomputer simulation produced star formation within a few light-years of the Milky Way’s central black hole.
“We don’t understand the environment at the galactic center very well yet,” Humphreys said. “By combining observational studies like ours with theoretical work, we hope to get a better handle on what’s happening at our galaxy’s core. Then, we can extrapolate to more distant galaxies.”
This just in from Scott Miller at Astronomy Cast LIVE. Once again we will be providing live video coverage of press events at the 213th A A S meeting being held in Long Beach CA Jan 5-8th. The video streams can be found here.
If for some reason this link does not work try searching for Astronomy Cast on at www.ustream.tv
Here is our tentative schedule for today, Monday January 5, 2009. Please check back with Astronomy Cast LIVE for updates. All times are Pacific Standard Time so please adjust accordingly. These recordings may or may not be available for viewing later.
9:30 AM – Exoplanets and Exoplanetary Systems
11:00 AM – Brown Drawfs
12:30 PM – Milky Way
3:00 PM – International Year of Astronomy 2009 Begins in USA
More videos from the AAS meeting will be added to the list tomorrow morning. Remember to join the chat room to suggest questions, and report issues. We will do our best to accommodate.
Prepare for a week of breaking astronomical news as the American Astronomical Society (AAS) is holding its 213th meeting all this week in Long Beach, California. Thousands of astronomers will be coming together to share their research and report their recent findings. Universe Today’s Fraser Cain and Ian O’Neill will be in attendance to provide on-site coverage, as well as tracking down the inside scoops and behind the scenes news. In addition, at our sister site Astronomy Cast LIVE, Fraser and Ian will be joining the team of Pamela Gay, Chris Lintott, Michael Koppelmann, Jordan Raddick, Georgia Bracey, and Scott Miller to post articles, do live-blogging and provide U-Stream live video from press conferences and other events. I’ll be manning the trenches from the ‘home office,’ reporting on AAS press releases and keeping track of the rest of news going on this week.
So get ready for a ridiculous amount of coverage and some very interesting discoveries that will be announced this week from the AAS meeting.
If you live near Long Beach or are there for the meeting, meet Fraser, Ian and the Astronomy Cast LIVE team at a “Blogger Meet-up” on Wed. January 7 at the Rock Bottom Brewery from 6pm – 9pm.
And if you are in the area, Tuesday night is the International Year of Astronomy opening ceremony at the Long Beach conference center. Observing sponsored by Celestron will take place outside before the 7:45pm ceremony.
The nominations are in, the votes have been counted and the Universe Today writers have been consulted; the Top 10 Scientific Endeavours of 2008 are decided! After much consideration by the readers of the Universe Today, it became quickly apparent what the popular choice would be, and some of the Top 10 may not come as a surprise. However, there are some nominations we weren’t expecting, and certainly cannot be found on any other “Top 10” list. Therefore, I believe the Universe Today’s Top 10 Scientific Endeavours of 2008 is the most comprehensive list out there, combining the votes of our readers, nominating a huge variety of articles available through one of the biggest space news websites on the Web.
Without further ado, here is the Universe Today’s definitive Top 10 Scientific Endeavours of 2008…
10. Chandra X-ray Observatory
Chandra X-ray image of M84 (NASA/CXC/MPE/A.Finoguenov et al.); Radio (NSF/NRAO/VLA/ESO/R.A.Laing et al); Optical (SDSS)Launched on July 23rd 1999, NASA’s Chandra X-Ray observatory has opened our eyes to the X-ray Universe. Chandra was named in honour of the late Indian-American Nobel laureate, Subrahmanyan Chandrasekhar. Subrahmanyan was known to the world as Chandra (which also means “moon” or “luminous” in Sanskrit) and he was regarded as one of the most influential astrophysicists of the 20th Century. It is fitting that one of the most influential X-ray observatories of the start of the 21st Century should bear his name.
In short, Chandra is an astounding mission, continuing to shape our understanding of known X-ray phenomena, providing us with a glimpse at the answers to some of the most puzzling questions of our time. Certainly one of the “Great Observatories”.
9. Epsilon Eridani This artist's conception shows the closest known planetary system to our own, called Epsilon Eridani. Credit: NASA/JPL/CaltechThe star system of Epsilon Eridani has provided astronomers with a tantalizing look into past of our very own Solar System since 2000. Being the ninth closest star to our Sun, it is also fairly easy to observe. At approximately 850 million years old, it is effectively what our system will have looked like when it was young; scattered disks of asteroids and dust, with exoplanets orbiting the star. Astronomers have even half-jokingly formed the link between Star Trek‘s fictional world of “Vulcan” with one of the large exoplanets known to be shaping one of the asteroid belts.
In 2008, further work has been done analysing the structure of the Epsilon Eridani system and there is even more evidence to suggest the star system is the Solar System’s “twin”. Although the star itself is slightly smaller and cooler than the Sun, it does possess several unseen planets, creating an asteroid belt much like ours, plus an outer belt (analogous to our Kuiper Belt, but 20-times bigger). Regardless of the similarities between the Solar System and Epsilon Eridani, it is a phenomenal achievement to probe an alien star system, over 10 light years away, with such precision.
8. Galaxy Zoo’s discovery of Hanny’s Voorwerp A highly scientific illustration of the Voorwerp (Galaxy Zoo)In Dutch, “Voorwerp” means “object” and this “object” was discovered by Dutch schoolteacher Hanny van Arkel last year using the Galaxy Zoo project. Since then, this strange astronomical entity has captivated enthusiasts and professionals alike. In May, astronomers came a step closer to understanding what this object was, as Bill Keel explains:
“Our working hypothesis is that Hanny’s Voorwerp consists of dust and gas (maybe from a tidally disrupted dwarf galaxy) which is illuminated by a quasar outburst within IC 2497, an outburst which has faded dramatically within the last 100,000 years.”
Galaxy Zoo is a superb example on how enthusiasts can use an Internet-based system to observe and identify objects in the cosmos. I am sure Hanny’s Voorwerp will continue to captivate professionals and amateurs, ensuring Galaxy Zoo’s popularity through 2009 and beyond…
7. MESSENGER The MESSENGER spacecraft at Mercury (NASA)The MErcury Surface, Space ENvironment, GEochemistry and Ranging (MESSENGER) spacecraft was launched by NASA in 2004 to begin an epic journey deep into the Solar System. Its eventual target would take it on a speedy roller-coaster ride via a series of Earth, Venus and Mercury flybys to slow its descent into the Sun’s extreme gravitational well. It won’t achieve orbital insertion until March 2011.
In January 2008, MESSENGER performed its first Mercury flyby. This is the first time for 30 years that the smallest planet* in the Solar System has been visited by a space mission (since the 1975 Mariner 10 mission flyby). There will be one more Mercury flyby until MESSENGER’s delta-v (change in velocity) has been slowed significantly to allow the spacecraft to be captured by the planet’s gravitational pull. During the January flyby, MESSENGER managed to capture some stunning images of the planet from an altitude of 200km. Then, in October the spacecraft made its second pass over Mercury’s surface from the same distance, revealing even more detail of the cratered, rocky surface.
After 3 decades, the mysterious planet, famous for being the closest planet to the Sun, is gradually revealing its secrets.
*Of course, when MESSENGER was launched, it was travelling to the second smallest planet in the Solar System. As Pluto was demoted in 2006, Mercury is now the smallest planet, whereas Pluto is a “dwarf planet” or a “Plutoid”.
6. First exploding supernova observed First supernova caught in the act (Alicia Soderberg, Princeton University)In January, something very special happened to a group of astronomers using NASA’s Swift X-ray satellite to study data from a month-old supernova remnant in a distant galaxy. In a case of “extreme serendipity”, the same galaxy produced another supernova the astronomers were able study right as it happened. This was the first time ever that astronomers caught a supernova in the act, we usually have to make do with studying the debris (or “remnant”) after a supernova has occurred.
“It’s a really lucky chain of events — a surprise,” said Alicia Soderberg, who is leading the group studying data from the explosion. “It was all over in a matter of minutes.”
This discovery is critical to understanding the science behind the final moments of a massive stars life, improving and advancing stellar models.
The complexity of the Large Hadron Collider (CERN/LHC/GridPP)
2008 has been the year for particle accelerator physics. The Large Hadron Collider (LHC) is the biggest physics experiment ever built, primarily to search for the elusive Higgs boson (the “force carrier” of the Higgs field that is theorized to permeate through the entire Universe, giving matter its mass), is as famous as it is infamous.
Early in the year, months before the 27km-long particle accelerator ring went online to circulate its first protons, the world’s media was abuzz with the possible science that could revolutionize physics as we knew it. However, there’s a flip-side to that coin. There was an increasing opposition to the LHC, culminating in attempted legal action (that ultimately failed), based on the flawed thinking that the LHC could generate dangerous micro black holes, strangelets and a host of other hypothetical particles. This only served to stir up international interest in what the LHC was actually going to do, and by October 10th, a mix of concern and excitement built up to the grand “switch on”.
Although many would argue the LHC shouldn’t be included in a “Top Ten Scientific Discoveries” (like Time Magazine’s Top Ten), as it hasn’t actually discovered anything yet, the LHC is a huge science and engineering endeavour, where its construction is as ground-breaking as the potential science it will be producing later this year.
Having recently completed its initial four-year tour of duty around the ringed planet, Cassini had its mission extended through September 2010. In August 2009, the Sun will shine directly on Saturn’s equator, illuminating the northern hemisphere. It is for this reason, the new phase of Cassini’s operations has been called the “Cassini Equinox Mission”.
The principal reason for extension is to find answers to some of the most perplexing questions raised during the spacecraft’s flybys of the Saturnian moons, principally Enceladus, the small 500km-diameter natural satellite. Enceladus may only be a tenth of the size of Titan (Saturn’s biggest moon) but it is one of the most intriguing.
“Of all the geologic provinces in the Saturn system that Cassini has explored, none has been more thrilling or carries greater implications than the region at the southernmost portion of Enceladus,” said Carolyn Porco, Cassini imaging team leader.
The SpaceX Falcon 9 being assembled at Cape Canaveral on Dec. 30th (SpaceX)
In August, the world watched in anticipation as SpaceX made its third attempt at becoming the world’s first commercial space flight company to launch a payload into orbit. Unfortunately, Flight 3 of the SpaceX Falcon 1 rocket became the third Falcon to fail, exploding high in the atmosphere after a stage separation (transient thrust) anomaly. It was a sad day not only for Elon Musk’s dream of providing affordable launch capabilities, but also for the promise of commercial space flight.
But in the true entrepreneurial spirit Musk has become synonymous with, his company turned Flight 3’s loss into a motivation to get it right the fourth time around. Only one month later, the Falcon 1 was readied for Flight 4 from the Kwajalein Atoll launch pad. On September 28th, SpaceX was propelled into the history books as the first ever private space company to design, build and launch a payload (albeit a “dummy” payload) into orbit.
Now SpaceX has proven itself to the world, the future has become very bright for commercial spaceflight. SpaceX not only got into orbit, they did it cheaply and quickly, setting the bar very high for its competitors. They also have a bold vision for the future; building bigger and more powerful rockets (the Falcon 9 for example), launching not only from the South Pacific, but also from the home of rocket launches: Cape Canaveral.
To top it all off, NASA has signed contracts worth $2.5 billion for private launch capabilities over the next decade, with SpaceX receiving a $1.6 billion share. All in all, it has been an outstanding year for SpaceX, and it looks like they might even be ready to supply the International Space Station in 2009, so watch this space.
Hubbles view of the exoplanet Fomalhaut b (NASA/HST)
We’ve known for many years that exoplanets orbit other stars and have observed them indirectly by looking at star “wobble” (due to gravitational effects of a massive exoplanet as it orbits) and exoplanet transits (as the planetary body passes in front of the star, reducing the amount of light received on Earth). This year astronomers went one better, they observed exoplanets directly, imaging the little dots as they orbit their host stars.
As if that wasn’t enough, on November 21st, astronomers using the ESO Very Large Telescope detected an exoplanet in a very compact orbit around Beta Pictoris, 70 light years from Earth.
These stunning glimpses of exoplanets have been made possible by the huge technological advancement in both ground-based and space-based observatory optics. Astronomers are now confident that they can go one step further as telescopes and techniques improve… how about looking for exomoons orbiting these exoplanets? Wow…
In May, the Phoenix Mars Lander captured the world’s attention as it entered the Martian upper atmosphere to begin its “7 minutes of terror“, including a fiery re-entry, fast decent and rocket-powered controlled landing. The robotic lander touched down in the frozen arctic region of the planet to begin its three month campaign with panache. The mission was extended to five months as Phoenix wrestled with the dwindling winter sunlight powering its solar panels and battled against troublesome dust storms.
This mission was also remarkable for the efforts carried out here on Earth by the Phoenix team at NASA and the University of Arizona communicating cutting-edge and up-to-the-minute science via a variety of social platforms. Scientists blogged and Twittered from the moment the mission was launched to the moment Phoenix finally succumbed to a frozen coma in early November (and MarsPhoenix continues to tweet regular data analysis updates).
However, this short mission joined the two rugged Mars Exploration Rovers Spirit and Opportunity soldiering through the elements for the last five years, after repeatedly having their missions extended over four years past their warranty. Add these incredible surface missions to the armada of satellites (NASA’s Mars Reconnaissance Orbiter, Mars Odyssey and the European Space Agency’s Mars Express), and it becomes obvious that international efforts to study Mars have turned the once mysterious, dusty red globe into one of the most studied planetary bodies of the last decade.
*****
So, Phoenix and the continuing Mars program overwhelmed the popular vote in the Top 10 Science Endeavours of 2008, winning the number one spot convincingly. This was a very tough “Top 10” to compile, but with the help of Universe Today readers, the list became more varied than we could have possibly hoped.
Naturally, many worthy science endeavours didn’t make the cut and here’s the runners up:
The Universe Today’s Top 10 Scientific Endeavours of 2008 highlights some of the huge scientific advances we have made in the last 12 months. 2009 promises to be even bigger, and with the help of the organizers of the International Year of Astronomy, global efforts in space won’t only be recognised, they will be celebrated.
Phoenix's descent captured by HiRISE. Credit: NASA/JPL-Caltech/University of Arizona
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I’ve been meaning to put together an article highlighting the best space and astronomy pictures of 2008, but I see time is slowly slipping away from me to get this out before 2008 turns into 2009. However, I’m in luck! A few people have already done the work for me, and so I’ll just link to them. First, of course, is Phil Plait over at the Bad Astronomy Blog, who does his annual Top Ten Astronomy Pictures, and this year’s choices by the BA were excellent. Next, Dave Mosher over at Discovery Space has just put together a slideshow of his picks for the Best Space and Astronomy Pictures of 2008. Nice job, Dave! And this just in (update 8:10 pm) — Emily Lakdawalla at the Planetary Society Blog has a great selection of The Year in Pictures 2008. Thanks Emily!
There are more links below, but I know if I would have done a list myself, the image above would have been my #1 pick. This shot by the Mars Reconnaissance Orbiter’sHiRISE Camera of the Phoenix lander descending through Mars’ atmosphere is truly outstanding. It’s an unbelievable shot, and I’ll always remember how my jaw dropped in disbelief when I first saw it.
And now back to everyone else’s best pics of 2008 lists:
I recently came across this site from and television station in India that put together a list of the 50 (wow! 50!) Best Astronomy Pictures of 2008.
The Boston Globe’s The Big Picture put together an “Advent Calendar” of 25 pictures from the Hubble Space Telescope that is well worth the trip if you haven’t already browsed through the nice and roomy images. I think my favorite is #9.
Located on the ecliptic plane, Pisces is a constellation of the zodiac and one of the 48 original constellations listed by Ptolemy. Spanning approximately 889 square degrees of sky, Pisces ranks 14th in constellation size, despite its faint stars. It contains 21 main stars in its asterism and has 86 Bayer Flamsteed designated stars within its confines. Pisces is bordered by the constellations of Triangulum, Andromeda, Pegasus, Aquarius, Cetus and Aries. It can be seen by all observers located at latitudes between +90° and ?65° and is best seen at culmination during the month of February.
There is one annual meteor shower associated with Pisces which peaks on or about October 7 of each year. The Piscid meteor shower has a radiant near the Aries constellation and produces an average of 15 meteors per hour which have been clocked at speeds of up to 28 kilometers per second. As always, the meteoroid stream can begin a few days earlier and end a few days later than the expected peak and success on viewing depends on dark sky conditions.
In mythology, the constellation of Pisces is represented by two fish bound together with a piece of string. According to one Greek myth, Pisces represents the fish into which Aphrodite and her son Eros transformed in order to escape the monstrous Typhon; they are tied together with a cord on their tails, to make sure they do not lose one another! Even more mythology states that Pan changed himself into a goat-fish (Capricorn) and jumped into the river to save them… Or perhaps it was a pair of fish which rescued them from the reeds along the river banks… Or maybe they were turned into eggs that were saved by the fish… One thing is for certain, somewhere along the line, the translation got lost – but the twin fish got left in the sky!
Let’s begin our tour of Pisces with binoculars as we take a look at it’s Alpha star – the “a” symbol on our map. Crowned with the traditional name of Alrischa – “Knot In The Rope” – 139 light year distant Alpha Piscium surely isn’t the brightest in the sky, nor the easiest to find. However, once located, take the time to power up in a telescope because Alrischa is a close binary star with angular separation of presently 1.8″ between the components. While the secondary star is separated from the primary by about one stellar magnitude, take note of their soft color. Both are A type stars, but many observers have reported seeing them as white and pale blue. What’s more, each of the chemically peculiar components might also be spectroscopic binary stars, too!
Now, let’s take a look at Beta Piscium in binoculars – the “B” symbol on our map. Located 495 light years from Earth, Samakah, the “Fish’s Mouth”, is a B-class hydrogen fusing dwarf star. It produces 750 times more light than our own Sun and rotates fully on its axis in about 2 days. At 60 million years old, one day Samakah will become a giant star, losing 80% of its mass in its high velocity solar winds and eventually become a white dwarf star.
Time to have a look at the brightest star – Eta – the “n” symbol. This unusual, bright class B star is located 294 years away from our solar system and has the unique distinction of being one of the few of its class to have had its angular diameter measured. It is about 26 times larger than Sol and shines almost 316 times brighter! However, Eta is a dying star… reduced to internal helium fusion. If you power up in a telescope, perhaps you’ll catch a glimpse of this binary star’s small, disparate companion located about a second of arc away.
Now aim binoculars towards Gamma – the “Y” symbol on our chart. Gamma is a yellow-orange giant star located about 130 light years distant. Oddly enough for a giant, it only puts out about 61 times more light than our Sun – but with good reason… it’s currently fusing it’s core to carbon. Right now, it is waiting to become a white dwarf, but that’s not what distinguishes Gamma – it is its speed. Apparently Gamma came from outside our Milky Way Galaxy altogether! According to its low metal content and cyanogen-weak spectral signature, Gamma had to have originated outside the galactic disc and it is still traversing the sky at over three-quarters of a second of arc per year!
For a very nice optical double star in binoculars, take a look at Kappa – the “K” symbol… or better yet, turn a telescope towards TX Piscium. It’s a gorgeous carbon variable star, which shines a deep, ruby red and varies by about a magnitude with time.
Now, let’s talk some deep sky and a Messier catalog object. Located about about 1/2 degree North and 1 1/2 degree East of Eta Piscium (RA 01 : 36.7 Dec +15 : 47), grand design spiral galaxy, Messier 74 isn’t always an easy object for small telescopes and will require dark skies and good viewing conditions to be seen in binoculars. Discovered 1780 by Pierre Méchain, and later cataloged by Charles Messier, this 95,000 light year distant island of light is about the same size as our Milky Way galaxy. When viewing M74 is smaller optics, be sure to look for a very precise, almost stellar nucleus and faded, wispy spiral galaxy structure.
For a big telescope challenge, try your luck with NGC 676 (RA 01h 48m 57.3s Dec +05° 54′ 25.8″). It is also a spiral galaxy with a bright, sharp nucleus, but seen more edge on. At magnitude 11 and about 4 arc minutes in size, it isn’t going to be easy – but what challenge is?
Perhaps you’d like to try NGC 474 (RA 1 : 20.1 Dec +03 : 25), too. It’s a huge elliptical galaxy with tidally disrupted tails from galaxy interactions with nearby NGC 470. While NGC 474 is billed at magnitude 11, you’ll find its stellar bright nucleus so distracting that magnitude 12 NGC 470 will at first appear to be the brighter of the two. While averting your vision, see if you can catch magnitude 13 NGC 467 to the north as well. It is by far the smallest of this galaxy group!
As a curious note, the Vernal Equinox is currently located in Pisces and, due to the precession of the equinoxes, is slowly drifting below the western fish towards Aquarius. In astronomy, equinox is a moment in time at which the vernal point, celestial equator, and other such elements are taken to be used in the definition of a celestial coordinate system. The position at other equinoxes can be computed by taking into account precession, nutation and aberration, which directly affect e.g. right ascension and declination.
January 1 of 2009 brings with it the International Year of Astronomy, a worldwide celebration commemorating Galileo Galilei’s first astronomical observation through a telescope. 135 nations are collaborating to promote astronomy and its contribution to society and culture, with events at regional, national, and global levels, to bring the Universe closer to more people on Earth. Events and activities will take place over the coming 365 days and beyond. How can you participate? Here’s a list of several IYA activities events taking place during the next year. If you or a group you are affiliated with are hosting an IYA event, feel free to post it in the comments section. The International Year of Astronomy 2009 (IYA2009) has been launched by the International Astronomical Union (IAU) and the United Nations Educational, Scientific and Cultural Organization (UNESCO). With so many events, the IYA is sure to make “The Universe, yours to discover.”
365 Days of Astronomy Podcast. This one is near and dear to my heart, as I’ve been part of the group of great folks working behind the scenes to launch this project. This project will publish one podcast per day, for all 365 days of 2009. The podcast episodes are written, recorded and produced by people around the world. And what great topics people are submitting! Tips for using your first telescope, celebrating 5 years of the Mars Exploration Rovers, Top Ten Reasons Stargazing is Cool, and the link between space and beer are just a few of the titles from the first few weeks. Listen every day, and if you’d like to participate by contributing a podcast of your own (less than 10 minutes in length) check out the 365 Days of Astronomy website on how to record and submit a podcast. You’ll be hearing my voice a few times during the year (in fact, listen to the January 1 podcast!) as well as the voices of Fraser Cain and Ian O’Neill, too, and many others. So you don’t miss a single one of the 365 podcasts, subscribe via RSS, or iTunes. And here’s the 365 Days of Astronomy trailer, reminding you to listen every day.
Opening Ceremonies: Many nations are holding their own Opening Ceremonies in January and February, showing their dedication to the Year. The official opening ceremonies take place in France on Jan. 15 and 16, but is not open to the public. Check out this website for opening ceremonies in your country.
Solar Physics. Don’t be surprised to see telescopes on the streets on New Year’s Day. The IYA2009 Solar Physics Group have been busy planning a grand worldwide campaign, with over 30 countries involved at more than 150 venues, which will see amateur stargazers set up their telescopes on pavements as well as in science centers, letting passers-by observe the Sun using special safety equipment.
The Cosmic Diary is an example of a global activity occurring during 2009, with the release of its official website on New Year’s Day. The project concerns the daily lives of full-time astronomers. More than 50 bloggers, professionals from over 35 countries and employed by organisations such as ESO, NASA, ESA and JAXA have already begun producing content, writing about their lives, the work they conduct and the challenges they face. The public can see what being an astronomer is really like, and how ground-breaking research is conducted.
100 Hours of Astronomy: April 2-5, 2009. Includes a wide range of public outreach activities such as live webcasts, observing events and more. One of the key goals of 100 Hours of Astronomy is to have as many people as possible look through a telescope, just as Galileo did for the first time 400 years ago. Check out 100 Hours of Astronomy’s website.
From Earth to the Universe. This is exhibition that will bring large-scale astronomical images to a wide public audience in non-traditional venues such as public parks and gardens, art museums, shopping malls and metro stations. Over 30 countries around the world are currently in the development phase of FETTU projects, many with multiple locations. Some 15 countries plan to begin FETTU exhibitions within the first month of 2009, ranging in size from 25 to over 100 images on display. FETTU will be introduced to the global community at the Opening Ceremony at UNESCO headquarters in January 2009. Find out more at their website.
The World at Night. Brings to the public a collection of stunning photographs and time-lapse videos of the world’s landmarks with the sky in the background. The World at Night is preparing more than 30 exhibitions and educational events around the world.
Dark Skies Awareness. One of IYA2009’s aims is to raise awareness of light pollution, and how the beauty of the night sky is progressively being drowned out, particularly over urban areas. The project Dark Skies Awareness is tackling these issues head-on in a practical, inclusive manner. One way in which it is doing this is by holding star-counting events, where the public are encouraged to see how many stars in a particular area of the sky are actually visible from their location. When compared with data from truly dark sites, the results are often very surprising! The “How Many Stars” event will run from January 2009.
IYA2009 wants to involve the public at many events, and amateur astronomers are organizing events. Known for their enthusiasm, this army of helpers is growing every day, preparing to promote astronomy in a stunning variety of ways. In fact, so many thousands of people across the globe are already involved, they have formed the world’s largest ever astronomy network. Please feel free to add info in the comments section for any events you know of. Thanks!
The Andromeda galaxy is the closest spiral galaxy to the Milky Way (though it’s not the closest galaxy). It’s the most distant object you can easily see with the naked eye (under good observing conditions). Andromeda is 220,000 light years in diameter, and is one of the 35 objects that make up what is called the Local Group. Andromeda lies, of course, in Andromeda constellation.
The Andromeda galaxy (also known as Messier 31, M31, or NGC 224) could be considered the big brother of the Milky Way, as it contains over a trillion stars (compared to our 200-400 billion), and is approximately 220,000 light years across to our 100,000. Andromeda and the Milky Way formed at roughly the same time – 13.5 billion years ago – near the beginning of the Universe. Our galaxy is thought to look much like Andromeda. Both Andromeda and the Milky Way got to their current size by eating up other galaxies they collide with. The expansion of the Universe causes most galaxies to move away from us, but Andromeda and the Milky Way are actually headed towards each other.
Andromeda and the Milky Way are good neighbors, but eventually our neighbor is going to move in with us – the Milky Way and Andromeda are approaching each other at 200 kilometers per second, and will eventually collide. There’s no need to panic, though, as Andromeda is over 2 million light years away, and the collision won’t happen for another 2 or 3 billion years. Astronomer John Dubinski of the University of Toronto has an excellent animated simulation from multiple perspectives of what this galactic dance could look like.
The collision between Andromeda and the Milky Way won’t be catastrophic, and after about 5 billion years from now the resulting galaxy will have settled down into an elliptical galaxy. There is a small chance, though, that the Sun won’t be part of this new “Milkomeda” galaxy.
Fraser and Pamela discuss how the collision between the Milky Way and Andromeda will look from Earth in the September 28th, 2008 episode of Astronomy Cast, and the Milky Way in Episode 99.
