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The Future of the Universe.
One of the most bizarre objects in the solar system has got to be Saturn's Moon Hyperion. From the pictures taken by Cassini, this tiny Moon looks like a sponge you might buy at the Body Shop. In a new research paper appearing in the July 5 issue of the journal nature, scientists have mapped the surface of Hyperion, and found hydrocarbons, some of the building blocks of life. And they also think they know why it has such a bizarre look.
The information was gathered by Cassini's ultraviolet imaging spectrograph and visual and infrared mapping spectrometer. These two instruments are able to map mineral and chemical constituents of a surface. In this case, the surface of Hyperion. It found that most of the surface is a mix of frozen water and organic dust, as well as trace amounts of frozen carbon dioxide.
But the key Discovery are these hydrocarbons; combinations of carbon and Hydrogen atoms. When these molecules are embedded in ice and then exposed to ultraviolet radiation, new complex molecules can form that are present in life.
In addition to the surface analysis, Cassini also helped scientists work out why the Moon has such a bizarre spongy appearance. It all comes down to an extremely low density. According to new calculations, the Moon has only half the density of water. Its low gravity means that normal processes, such as crater formation work differently than on more dense objects in the Solar System. Objects that impact Hyperion plunge in, compressing the surface instead of blasting out the familiar looking craters.
The Future of the Universe
Life was so much simpler when a person's world extended no further than a long day's walk, while a night time's pleasure was viewing twinkling diamonds. But now we know that Earth's continents rush around like bumper cars. Our Sun eats so much Hydrogen that it's going to explode. And our Galaxy is crashing its way through another. These severe sounding events, and others, permeate through the book The Future of the Universe by A.J. Meadows. And, as it shows, our simplistic view is being well replaced by much grander visions.
As this book's title aptly implies, our universe and all its contents are changing and leading to a future that's different from today. With this assurance, Meadows' book discusses what we may expect as time unfolds. True, we personally won’t have to worry about much of it. The discussed time frames extend from thousands to billions of years into the future. However, this book raises a profound surreal feel by giving the reader knowledge of the future, even if not for the near-term. Or at least, the odds say that there won't be a comet impacting, or magnetic twist, or a dimming Sun any time soon. For, though this book describes the processes, the moment is up to anyone's guess.
Given that the 'when' is unknown, Meadows concentrates upon the 'what' in his book. And the 'what' refers to local changes, such as with our Sun's radiation level, the Earth’s heat flow, or the vagaries of the Earth's atmosphere. With these, he's assured the reader that we are very fortunate that so many things came together to support life. Yet, he presses on. He heads out to consider asteroids, comets and neutron star explosions. Last, in looking at the really big picture, there's galactic curtains and the local bubble that come into play. All these have or could impact Earth and the life that holds fast upon its surface.
This consideration of life is the main driver in Meadows' book. He clearly shows that innumerable events can and very likely did greatly effect all types of life throughout history. Whether a wobbling Sun, a wayward asteroid, or colliding brown dwarfs, he shows that our solar system was and still is interacting with many nasties of space. However, what really makes his book is the grand scale of the contents. There's nothing here for short-term insurance brokers. It's all about a long term and fascinating prognosis that our future on Earth is doomed. Meadows shows it's just a matter of time, eventually.
Though this consideration of our future appears too fanciful, Meadows bases it all upon well accepted principles and historical examples. Further, he recovers these principles in a straight forward, smooth manner. It's this deceptive style of writing that misleads the reader into understanding the big picture without worrying about the details. Given this style, the book's well geared toward a reader without a technical background. To do this, Meadows also keeps the language at a generalist level. If you’re comfortable reading a broadsheet newspaper, then you will have no problem with this book. Yet, hiding behind the easy going prose lie the reasoning about the life of stars, the formation of planets and the possible existence of other universes.
Though the book doesn’t come across as a wake up call for our species, it certainly will add to the impetus. For certainly, in reading it, anyone will realize that our little bit of paradise called Earth is going to have a rough finale. For those who like the big picture, whether a specialist or simply curious, this book connects together many of these disparate dots.
Our Sun seems never to change. And, only with great patience do we know for certain that the stars move independently across the night sky. But the universe is anything but a calm quiet place. A.J. Meadows in his book The Future of the Universe shows that not only is the universe a busy place, it's also going to be quite nasty for life on Earth.
Read more reviews online, or purchase a copy from Amazon.com
Astrosphere for July 6, 2007
Sorry for the bloglessness yesterday, I was running another load of stuff to the new house. Now all our stuff's together again, we just have to cram a house's worth of belongings into an apartment.
Here's another astrosphere:
Today's astrophoto is of Jupiter and its 4 easy-to-see moons. It was taken by forum member Bokmakierie.
First, I'd like to point your browser towards the Carnival of Space #10. I didn't get an entry in this time around, but it's still good quality all around.
Becky Ramotowski published her picture of Comet C2006 VZ13 LINEAR
Phil Plait reviews the Transformers to find some bad science and finds the movie surprisingly entertaining.
Daily Galaxy has a story on the Theia Hypothesis. More evidence that the Earth and the Moon were once the same.
What's Up this Week: July 2 - July 8, 2007
Monday, July 2 - Orbiting in space 40 years ago, the Vela 3 and 4 satellites were quietly keeping watch on Earth's nuclear test ban treaty. The Vela satellites were greatly successful and far exceeded their life expectancy. While checking data on this day just before the launch of the fifth Vela, scientists found an event recorded by Vela 4 - an event also strong enough to trigger a response from the Vela 3 satellite. While placement wasn't accurate enough at the time to pinpoint the source, the scientists realized they had caught the first recorded gamma ray burst.
While very little is known about these mysterious events, we do know that they occur about once a day with a photon energy of 100 million electron volts. While some of them occur in our own Milky Way, science is unclear about the source of more distant explosions - and over 800 have been charted on a single map! One such source for gamma rays is a special type of star known as a Wolf-Rayet - a hot, huge star which is undergoing significant mass loss and exposing its central core.
Tonight for more southern viewers, take the time to look up one such incredible system, IC 4406. You'll find it about 5 degrees northwest of Alpha Lupi, or just about a fingerwidth northwest of the Tau collection (RA 14 22 26.28 Dec -44 09 04.3). This roughly 10th magnitude planetary nebula is sometimes referred to as the "Retina Nebula" for its photographic resemblance to the human retina. This square appearing patch is a Wolf-Rayet nebula and color photographs show evidence of gamma rays as green sparkles!
Tuesday, July 3 - If you're up before dawn, this morning would be a great opportunity to easily find Neptune around one degree north of the Moon.
Tonight for all observers, let's take a closer look at the fascinating constellation of Lupus southwest of brilliant Antares. While more northerly latitudes will see only roughly half of this constellation, it sits well at this time of year for those in the south. So why bother?
Cutting through our Milky Way Galaxy at a rough angle of about 18 degrees is a disc shaped zoned called Gould's Belt. Lupus is part of this area, and its perimeter contains star-forming regions that came to life about 30 million years ago when a huge molecular cloud of dust and gas compressed - much like in the Orion area. In Lupus we find Gould's Belt extending above the plane of the Milky Way!
Return again to the beautiful Theta and head around 5 degrees west for NGC 5986 (RA 15 46 03.44 Dec -37 47 10.1). It's a 7th magnitude globular cluster which can be spotted with binoculars with good conditions. While this Class VII cluster is not particularly dense, many of its individual stars can be resolved in a small telescope.
Now sweep the area north of NGC 5986 (RA 17 57 06.00 Dec -37 05 -0.0) and tell me what you see. That's right! Nothing. This is the dark nebula B 288 - a cloud of dark, obscuring dust which blocks incoming starlight. Look carefully at the stars you can see and you'll notice they appear quite red. Thanks to B 288, much of their emitted light is absorbed by this region, providing us with a pretty incredible on-the-edge view of something you can't see - a Barnard dark nebula.
Wednesday, July 4 - Did you know that celestial fireworks occurred in 1054 on this day? It is believed that the bright supernova recorded by Chinese Astronomers occurred at this point in history, and today we know its remnants as M1 - the "Crab Nebula."
But could such an event happen again in our own celestial "backyard?" Look no further than HR 8210 (RA 21 26 26.66 Dec +19 22 32.3). It may be nothing more than a White Dwarf star hiding out in late night Capricornus, but it's a star that has run out of most of its fuel. This rather ordinary binary system has a companion White Dwarf star that's 1.15 times the mass of our Sun. As the companion also expends its fuel, it will add mass to HR 8210 and push it over the Chandrasekhar limit - the point of no return in mass. This will result in a supernova event located only 150 light-years away from our solar system...50 light-years too close for comfort!
470 light-years away in the Gould Belt, and roughly 1.5 million years ago, a similar massive star exploded in the Upper Scorpius association. No longer able to resist its own gravitational mass by nuclear fusion, it unleashed a supernova event which left its evidence as a layer of iron here on Earth, and may have caused a certain amount of extinction when its gamma rays directly affected our ozone layer.
Take a long look at Antares tonight - for it is part of that association of stars, and is no doubt a massive red star also poised at the edge of extinction. At a safe distance of 500 light-years, you'll find this pulsing red variable equally fascinating to the eye as well as to the telescope. Unlike HD 8210, Alpha Scorpii also has a companion star which can be revealed to small telescopes under steady conditions. Discovered on April 13, 1819 during a lunar occultation, this 6.5 magnitude green companion isn't the easiest to split from such a bright primary - but it's certainly fun to try!
Thursday, July 5 - If the outer planets call you, then make a date before dawn to catch Uranus. Easily spotted in binoculars, the seventh planet from the Sun can be found about 1.7 degrees south of the Moon.
Tonight let's have a look at a real little powerpunch globular cluster located in northern Lupus - NGC 5824. Although it's not an easy star hop, you'll find it about 7 degrees southwest of Theta Librae and exactly the same distance south of Sigma Librae (RA 15 03 58.50 Dec -33 04 03.9). Look for a 5th magnitude star in the finderscope to guide you to its position southeast.
As a Class I globular cluster, you won't find any that is more concentrated than this. Holding a rough magnitude of 9, this little beauty has a deeply concentrated core region that is simply unresolvable. Discovered by E. E. Barnard in 1884, it enjoys its life in the outer fringes of the galactic Halo about 104 light-years away from Earth, and contains many recently discovered variable stars. Oddly enough, this metal poor globular may have been formed by a merger. In researching evidence found about NGC 5824's stellar population, it is believed that two less dense and differently-aged globulars may have approached one another at a low velocity and combined to form this ultra-compact structure.
Be sure to mark your observing notes on this one! It also belongs to the Bennett catalog and is part of many globular cluster studies. Enjoy...
Friday, July 6 - Today in 1687, Isaac Newton's "Principia" was first published with the help of Edmund Halley. Although Newton was indeed a very strange man with a highly checkered history, one of the keys to Newton's work with the theory of gravity was the idea that one body could attract another across the vastness of space.
Now let's have a look at things gravitationally bound as we start at Eta Lupi, which is a fine double star that can even be resolved with binoculars. Look for the 3rd magnitude primary and 8th magnitude secondary separated by a wide 15". You'll find it by staring at Antares and heading due south two binocular fields to center on bright H and N Scorpii - then one binocular field southwest.
When you are done, hop another roughly five degrees southeast to encounter the fine open cluster NGC 6124. Discovered by Lacaille, and known as object I.8, this 5th magnitude open cluster is also known as Dunlop 514, as well as Melotte 145 and Collinder 301. Situated about 19 light-years away, it will show as a fine, round, faint spray of stars to binoculars and be resolved into about 100 stellar members to larger telescopes.
While NGC 6124 is on the low side to northern observers, it's worth the wait for it to hit best position and at least try! Be sure to mark your notes, since this delightful galactic cluster is a Caldwell object and a southern skies binocular award.
Saturday, July 7 - Tonight for unaided observers, let's begin by identifying Zeta Ophiuchi, the centermost in a line of stars marking the edge of the constellation of Ophiuchus, about a handspan north of Antares. As a magnificent 3rd magnitude blue/white class O, this Hydrogen fusing dwarf is 8 times larger than our own Sun. Hanging out some 460 light-years away, it is dulled by the interstellar dust of the Milky Way and would shine two full magnitudes brighter if it were not obstructed. Zeta is a "runaway star" - a product of a one-time supernova event in a double star system. Now roughly halfway through its 8 million year life span, the same fate awaits this star!
Now point binoculars or small scopes about three fingerwidths south to have a look at Phi Ophiuchi. This is a spectroscopic double star, but it has several delightful visual companions!
Almost in between these two bright stars is our telescopic target for tonight - M107. Discovered by Pierre Méchain in 1782, but only added to the Messier catalog in 1947, it's probably one of the last of the Messier objects to be discovered, and it wasn't resolved into individual stars until studied by Herschel in 1793.
M107 isn't the most impressive of globulars, but this Class X is notable as a faint, diffuse area with a core region in binoculars, and is surprisingly bright in a small telescope. It's a curious cluster, for some believe it contains dark, dust-obscured areas which make it unusual. Located around 21,000 light-years away, this little beauty contains around 25 known variable stars. Visually, the cluster begins to resolve around the edges to mid-aperture and the structure is rather loose. If sky conditions permit, the resolution of individual chains at the globular's edges make this it well worth a visit to log as Herschel IV.40!
Sunday, July 8 - Tonight let's continue on our journey through the galactic Halo and pick up the Class VIII globular cluster M9. You'll find it located around two fingerwidths east of Eta Ophiuchi.
Discovered by Messier in 1764, this particular globular cluster is one of the nearest to our galactic center and is around 2,600 light-years away from our solar system. Now let's study differences - check out the contrast between this small globular compared to last night's M107. With M9 we're seeing not only a strong central concentration, but a slight oval shape. This change in structure is caused by the strong absorption of starlight by dust along its northwest edge. Of its huge stellar population, only a dozen or so variable stars are known in M9, which is rather few for a cluster of its size. Visually, it appears more compact than M107, and slightly oblate. Rather than chains of stars resolving at the edges, M9 appears to have larger, individual stars in a random pattern - while M107 appears to have a solid core!
For those with larger scopes, you also have the opportunity to study two more globulars that are nearby - Class II NGC 6356 about a degree to the northeast and Class IV NGC 6342 to the southeast. You will find NGC 6356 to be rather small - but bright and concentrated. NGC 6342 appears to be even smaller and far less distinct. Compare them both to the structure of M9 and you will find 6356 to be the most concentrated of the three...a "class" act!
Is There a Link Between Cosmic Rays and Global Warming?
As you might know, I've got a side job blogging over at Wired Science on their space beat. I just posted an article there about new research that refutes a possible connection between global warming and cosmic rays.
The theory is that cosmic rays create ions in the atmosphere, forming the seeds that build into water droplets. If true, that would help explain global warming as a natural phenomenon, where increased cosmic rays create clouds to cool the planet. When the 11-year solar cycle is at its maximum, cosmic rays are pushed away from the Earth, and temperatures rise. No humans causing global warming.
Except we are.
A new presentation at the 30th International Cosmic Ray Conference by researchers from the UK tears holes in this theory, refuting it on several levels.
How Jupiter Changes Over Time
We experience changing weather here on Earth. One day it's overcast, and then the next day has clear skies. Same goes for the other planets, it just happens on different timescales. The Hubble Space Telescope has been watching how the planet Jupiter's weather transforms over time - it happens surprisingly quickly.
The latest photographs released from Hubble show two pictures, before and after. The first picture was captured on March 25, and then the second was snapped on June 5. Between this period, entire bands on the planet have changed colour.
Regions where the atmosphere is rising are called "zones"; where the atmosphere is falling are called "belts". During this 3+ month period, many of these zones have transformed into belts, and vice versa.
Astronomers have seen these transformations before with ground-based observatories, but never with such detail. These Hubble images will help Astronomers better predict atmospheric changes on Jupiter. And perhaps even help explain how massive storms like the Great Red Spot can form.
Black Holes are Key to the Evolution of the Universe
A supercomputer simulation has retraced the evolution of the universe, giving Astronomers new clues on where they should point their telescopes. And it seems that one of the most important ingredients to this cosmic recipe is black holes.
The simulation is called BHCosmo, and it was performed on the Cray XT3 system at the Pittsburgh Supercomputing Center. The researchers tied up the whole system - 2,000 processors - for 4 weeks to run the simulation.
They started with initial conditions that matched the cosmic microwave background radiation. Next they seeded the area with 250 million particles of matter, and surrounded that with the gravitational force of dark matter. The researchers watched how the particles of matter collapsed to form galaxies and black holes.
One of the most important findings of the simulation was the impact of black holes. galaxies look the way they do because of the supermassive black holes at their centres.
Eventually they hope to model the entire universe with a resolution that matches the Sloan Digital Sky Survey, but that will take more computer power.
Hubble View of a Galaxy Ablaze in Star Formation
This latest image released from the Hubble Space Telescope shows the dwarf Galaxy NGC 4449, located about 12.5 million light-years away. Although the Galaxy has been around for billions of years, it recently went through a period of intense star formation.
Most starburst galaxies concentrate their stellar formation around the crowded galactic core, but in NGC 4449, the active regions extend out across more of the galaxy. This will only last for another billion years or so, when the gas supply that feeds the star forming regions runs out. It will then stay quiet until it has a close encounter with another galaxy, starting the process all over again.
A Galaxy like NGC 4449 resembles what the first primordial galaxies probably looked like, formed shortly after the Big Bang when the universe was young. Many small galaxies merged together forming larger and larger galaxies until they became the majestic spirals we see today. Each new merger brings in a fresh supply of raw materials as well as the gravitational interactions to force gas clouds to collapse.
NASA's New Einstein Probes Office
Albert Einstein made enough predictions about the nature of gravity and relativity that NASA has dedicated a whole office and fleet of spacecraft to him. This week the space agency announced their new Einstein Probes Office, where they'll be compiling evidence for the strangest stuff in the Universe: dark energy, black holes, and the cosmic microwave background radiation.
The Beyond Einstein program consists of 5 proposed spacecraft; two major spacecraft, and 3 smaller probes. The two major missions are already in the works, and include the Laser Interferometer Space Antenna (LISA), which will orbit the Sun and measure gravitational waves. Constellation-X will watch matter falling into supermassive black holes.
The smaller probes include missions to investigate the nature of dark energy, the physics of the Big Bang, and the distribution and types of black holes in the universe. NASA has already approved preliminary studies into some of these missions.
NASA and the U.S. Department of energy have put together a committee to figure out which missions should be launched first, and will release their findings in September, 2007.
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