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Mars rovers still wandering across Red Planet.
The long-lasting Mars rovers are still wandering across the surface of the Red Planet, but they're about to get a new friend. Next up to land on the surface of Mars is the Phoenix Mars Lander, which recently arrived in Florida in preparation for its upcoming launch. The Phoenix lander was delivered by a US Air Force C-17 cargo aircraft from its manufacturer in Colorado.
If all goes well, the Phoenix Mars Lander will blast off atop a Boeing Delta II rocket as early as August 3rd, 2007. It will make the six month trip to Mars, and then land in a flat plain near the planet's arctic ice cap. It will use its robotic digging arm and a suite of instruments to determine if the soil holds quantities of water ice - one of the necessary ingredients for life. The detection of ice would bring the possibility of microbial Life on Mars one step closer.
Workers from Lockheed Martin Space Systems have been assembling and testing the spacecraft in Denver for the last year. At this point, Phoenix is now safely stowed away inside its back shell, and will stay that way until it launches in August.
NASA will perform a series of tests over the next few weeks, and then install its heat shield and test its ability to separate from the launcher. Just a week before launch, the launch fairing will be installed around the lander and then it will be installed atop the Delta II rocket.
Original Source: http://www.nasa.gov/mission_pages/mars/news/phoenix-20070508.html
Astrosphere for May 9, 2007
Here's what I found, buzzing around the astrosphere today.
A Babe in the Universe had a great blog post about the Griffith Observatory, in Los Angeles. And then last night, the observatory nearly caught fire as part of the Griffith Park fire. My wife's Gilmore Girls episode was replaced with 60 minutes of helicopter footage of a raging fire about to consume a historic observatory. Mt. Stromlo all over again. Fortunately, the observatory seems safe.
The Daily Galaxy has an excellent piece on the 'Hawking Solution'. Leave the Earth to save humanity?
My Astronomy Cast cohost, Dr. Pamela Gay ponders on her Star Stryder blog what life might be like on Gliese 581c (that recently discovered, most-Earthlike planet)
My favourite news show is called the Hour, and it's all Canadian. They had a great interview with Richard Dawkins. Unfortunately, the official video clip is an obnoxious WMV file, but there's a YouTube version over at Cosmic Afterthoughts.
Saturn, Painted By Storms
This photograph of Saturn looks as if it was painted, or carved from a block of sandstone. That's because it was heavily processed on computer to bring out detail in the Ringed Planet's cloud structure. You lose the smooth natural look, but you get to see sharp detail in the atmospheric bands. The image was captured by NASA's Cassini spacecraft using a combination of spectral filters. Different wavelengths of infrared radiation represent different colours in the image.
Cassini captured the image on August 19, 2005 when it was approximately 492,000 kilometers (306,000 miles) from Saturn.
Original Source: http://saturn.jpl.nasa.gov/multimedia/images/image-details.cfm?imageID=2592
Book Review: Space Invaders
Robots are our autonomous surrogates. They faithfully travel wherever we fear to tread. Michel van Pelt in his book, Space Invaders – How Robotic spacecraft Explore the Solar System provides a practical look at these amazing machines that travel ever further from our home base on Earth. Though they get shaked, baked and rattled, they are the champions for long distance, harsh environment exploration.
Mechanical instruments and sensors duplicate and extend many of our abilities. For instance, their artificial eyes detect electromagnetic energy at frequencies will outside the visible spectrum. With a broad suite of such sensors, a machine can directly measure planetary magnetic fields and atmospheric composition and beam results back to Earth for further analysis. Coupling this with the ability to repeat endlessly and without complaints makes these mechanical marvels superbly suited for their task. With them extending our awareness ever further off Earth, we're knowing more and more of the surrounding universe.
Michel van Pelt's book treats these space borne proteges with care and attention. Two main themes are present. One follows the system design elements that typically constrain the complex space robots. The other is a description of the particular missions that they've completed, together with a brief description of their findings. Design work includes power supplies, Hoffman transfer routes, and transiting over rough ground. And, as with all such considerations, there's much ado in the book about cost and schedule for the robot programs. Luckily, there seems to be no shortage of people who want to get and use results, so at least that part of the program management doesn't need as much attention.
Understandably, our robotic servants do complex work that's based on elementary physics. However, van Pelt's book keeps well away from these esoteric niceties and remains with generalities. At times it dips into exotics, such as hypothesising how to travel in highly acidic pools on planets with variable gravity. But these serve to show the challenges and necessary flexibility in robotic design. As well, with a writing date of early 2006, it contains many current references, including Venus Express and the Mars Landers. From it, the reader can well appreciate the effort that goes into ensuring that robots can acquire the most useful information.
van Pelt enhances this distillation by using a simple writing style with little specialized nomenclature. Thus, the book is well suited to youths, young adults and those with a general interest. Yet, the content isn't trite as it deals with some of the most amazing discoveries made by our species. In recognition of this, van Pelt adds a fair amount of description of these discoveries; major surface features, ring structures and asteroid composition. With this, the reader will be left with no doubt about the capability and utility of our little mechanical assistants.
This book's weakness, however, is its lack of a solid appraisal of machines. Around us, a current, active debate tries to establish the value of human crewed space exploration versus an outreach based purely on machines. There's no reference to this in the book. It mentions the Apollo missions and the many robot successes but not as to which is better or what would be most rewarding in the future. This weakness leads into a second one. The book doesn't consider the immediate future of space robotics. It skips from today's probes and jumps to a future where squadrons of miniature flying sensors scour foreign climates. Hence, the reader is left staring off a cliff of success into a sea of uncertainty regarding the robots.
We are invading space with our machines. Their sensors give us first hand accounts of places we can only dream of visiting. Michel van Pelt in his book , Space Invaders – How Robotic spacecraft Explore the Solar System provides us with the design methodology of these machines, together with some of their discoveries. It shows the success of our invasion throughout the solar system.
How Dark matter Might Have Snuffed Out the First Stars
What role did Dark matter play in the early Universe? Since it makes up the majority of matter, it must have some effect. A team of researchers is proposing that massive quantities of Dark matter formed dark stars in the early universe, preventing the first generations of stars from entering their main sequence stage. Instead of burning with Hydrogen fusion, these 'dark stars' were heated by the annihilation of dark matter.
And these dark stars might still be out there.
Just a few hundred thousand years after the Big Bang, the universe cooled enough for first matter to coalesce out of a superheated cloud of ionized gas. gravity took hold and this early matter came together to form the first stars. But these weren't stars as we know them today. They contained almost entirely Hydrogen and helium, grew to tremendous masses, and then detonated as supernovae. Each successive generation of supernovae seeded the universe with heavier elements, created through the nuclear fusion of these early stars.
Dark matter dominated the early universe too, hovering around normal matter in great halos, concentrating it together with its gravity. As the first stars gathered together inside these halos of dark matter, a process known as molecular Hydrogen cooling helped them collapse down into stars.
Or, that's what Astronomers commonly believe.
But a team of researchers from the US think that Dark matter wasn't just interacting through its gravity, it was right there in the thick of things. Their research is published in the paper 'Dark matter and the first stars: a new phase of stellar evolution'. Particles of Dark matter compressed together began to annihilate, generating massive amounts of heat, and overwhelming this molecular Hydrogen cooling mechanism. Hydrogen fusion was halted, and a new stellar phase - a 'dark star' - began. Massive balls of Hydrogen and helium powered by Dark matter annihilation, instead of nuclear fusion.
If these dark stars are stable enough, it's possible that they could still exist today. That would mean that an early population of stars never reached the main sequence stage, and still live in this aborted process, sustained by the annihilation of dark matter. As the Dark matter is consumed in the reaction, additional Dark matter from surrounding regions could flow in to keep the core heated, and Hydrogen fusion might never get a chance to take over.
Dark stars might not be so long lasting, however. The fusion from regular matter might eventually overwhelm the Dark matter annihilation reaction. Its evolution into a regular star wouldn't be halted, only delayed.
How could Astronomers search for these dark stars?
They would be very large, with a core radius larger than 1 AU (the distance from the Earth to the Sun), so they might be candidates for gravitational lensing experiments. These observations use the gravity from nearby galaxies to serve as an artificial telescope to focus the light from a more distant object. This is the best technique Astronomers have to find the most distant objects.
They could also be detectable by the annihilation products of the dark matter. If the nature of Dark matter matches the Weakly Interacting Massive Particles theory, its annihilation would give off very specific radiation and particles in large quantities. Astronomers could look for gamma-rays, neutrinos, and antimatter.
A third way to detect them would be to search for a delay in the transition to the main sequence stage for the early stars. The dark stars could have interrupted this stage for millions of years, leading to an unusual gap in stellar evolution.
Perhaps these dark stars will give Astronomers the evidence they need to finally know what Dark matter really is.
Original Source: http://arxiv.org/PS_cache/arxiv/pdf/0705/0705.0521v1.pdf
Astrosphere for May 8, 2007
Here's another spin around the astrosphere. Interesting sites, stories and blogs I found while working on universe Today.
Want to fly into space, but you lack the cash? Jim Benson's Space Company is offering a free trip into space. You can visit the site, but there aren't many details yet. Give them your email to stay updated.
Have you signed up for a flight with Virgin Galactic? Maybe it's time you meet some of your shipmates. USA Today is profiling a few of them in a recent story. (Thanks to Personal Spaceflight for the info.)
The Science Channel is joining in the Space Week festivities with some appropriate shows, including a documentary on the new Orion spacecraft. We don't get the Science Channel here in Canada, so Tivo it for me. (Thanks to the Rocketry Blog for the link.)
Do you write space-related stories? Then you'll want to join the next Carnival of Space. If you've written an article about space, and want to get some new readers, join in. I'll do it if you do it. What's a blog carnival? Learn more.
Larry Kellogg gives a detailed look at the fuel cells that will keep astronauts in electricity on their flights back to the Moon.
Ariane 5 Lofts Two Satellites
An Ariane 5 rocket roared from the European Spaceport in French Guiana on Friday, carrying two satellites into geostationary transfer orbits. The liftoff occurred at 2229 UTC (6:29 pm EDT), after a one day delay because of high-altitude winds. The satellites were released into their transfer orbits 30 minutes after launch.
The first satellite is the ASTRA 1L, which will join a dozen spacecraft in the SES ASTRA constellation. They provide television broadcast and data communications services to 109 million households in Europe.
The second satellite is the Galaxy 17 broadcast satellite, built by Thales Alenia Space, and launched for Intelsat. It became Intelsat's 45th satellite launched aboard an Ariane rocket. Galaxy 17 will park above 74 degrees West above the equator, and provide broadcast services to North America.
This is the second Ariane 5 launch of the year; 4 more are planned.
Original Source: http://www.esa.int/esaCP/SEMOPTU681F_index_0.html
Chandra Sees the Brightest Supernova
NASA's Chandra X-ray observatory might have observed a brand new kind of supernova, or maybe it's just an unusually bright supernova. Whatever the case, the explosion of SN 2006gy seems to be the brightest supernova ever observed, flaring with 100 times the energy of a typical exploded star.
The team that discovered SN 2006gy think that the original star might have contained 150 times the mass of our Sun; only the first generation of stars that formed after the Big Bang were thought to be this massive. It was the Chandra X-ray observations that helped distinguish the supernova as originating from a massive star, and not the Type 1A associated with an exploding White Dwarf star.
A supernova occurs when a massive star consumes its fuel, loses outward pressure, and collapses inward under its own gravity. But in the case of SN 2006gy, there might be an entirely new process going on here. The precursor star could have been so large that its core produces a large amount of gamma rays. The energy from this radiation is converted into particle and anti-particle pairs, and causes a drop in energy. Without this energy, the star collapses from its own gravity early and detonates as a supernova.
Even though SN 2006gy is the intrinsically brightest supernova ever seen, it exploded in Galaxy NGC 1260, which is located about 240 million light-years away - so you need a powerful telescope to see it. The closest star that's in the same category is Eta Carinae, a massive star located only 7500 light-years away. No telescope will be necessary when it explodes.
Original Source: http://chandra.harvard.edu/press/07_releases/press_050707.html
What's Up this Week: May 7 - May 13, 2007
Monday, May 7 - Before we leave Leo to softly exit west, there is another Galaxy that is so worth your time to visit that even binoculars can spot it. You'll need to identify slightly fainter lambda to the southwest of Epsilon and head south about one fingerwidth for NGC 2903.
This awesome oblique spiral Galaxy was discovered by William Herschel in 1784. At a little brighter than magnitude 9, it is easily in range of most binoculars. It is odd that Messier missed this one considering both its brightness and the fact that three of the comets he discovered passed by it! Perhaps it was cloudy when Messier was looking, but we can thank Herschel for cataloging NGC 2903 as H I 56.
While small optics will only perceive this 25 million light-year distant beauty as a misty oval with a slightly brighter core region, larger aperture will light this baby up. Soft suggestions of its spiral arms and concentrations will begin to appear. One such knot is star cloud NGC 2905 - a detail in a distant Galaxy so prominent that it received its own New General Catalog designation.
NGC 2903 is roughly the same size as our own Milky Way, and includes a central bar - yet the nucleus of our distant cousin has 'hot spots' that were studied by the Hubble Telescope and extensively by the Arecibo telescope. While our own galactic Halo is filled with ancient globular clusters, this Galaxy sports brand new ones!
Be sure to mark your notes with your observations, because many different organizations consider this to be on their 'Best of' lists.
Tuesday, May 8 - Tonight we'll start with an object that can be viewed unaided from a dark location and is splendid in binoculars. Just northeast of Beta Leonis, look for a hazy patch of stars known as Melotte 111. Often called the 'Queen's Hair,' this five degree span of 5th to 10th magnitude stars is wonderfully rich and colorful. As legend has it, Queen Berenice offered her beautiful long tresses to the gods for the King's safe return from battle. Touched by her love, the gods took Berenice's sacrifice and immortalized it in the stars.
The cluster is best in binoculars because of its sheer size, but you'll find other things of interest there as well. Residing about 260 light-years away, this collection is one of the nearest of all star clusters, including the Pleiades and the Ursa Major moving group. Although Melotte 111 is more than 400 million years old, it contains no giant stars, but its brightest members have just begun their evolution. Unlike the Pleiades, The Queen's Hair has no red dwarfs and a low stellar concentration which leads Astronomers to believe it is slowly dispersing.
Like many clusters, it contains double stars - most of which are spectroscopic. For binoculars, it is possible to split star 17, but it will require very steady hands.
Wednesday, May 9 - While our destination tonight isn't quite so romantic, I think you'll enjoy getting a 'Blackeye.' You'll find it located just one degree east-northeast of 35 Coma Berenices and it is most often called M64.
Originally discovered by Bode about a year before Messier cataloged it, M64 is about 25 million light-years away and holds the distinction of being one of the more massive and luminous of spiral galaxies. It has a very unusual structure and is classified as an Sa spiral in some catalogs and an Sb in others. Overall, its arms are very smooth and show no real resolution to any scope - yet its bright nucleus has a incredible dark dustlane that consumes the north and eastern regions around its core - giving rises to its nickname - the Blackeye Galaxy.
In binoculars, this 8.5 magnitude Galaxy can be perceived as a small oval with a slightly brighter center. Small telescope users will pick out the nucleus more easily, but will require both magnification and careful attention to dark adaptation to catch the dustlane. In larger telescopes, the structure is easily apparent and you may catch the outer wisps of arms on nights of exceptional seeing.
No matter what you use to view it, this is one compact and bright little galaxy!
Thursday, May 10 - If you're up before dawn this morning, you'll find Neptune less than two degrees north of the Moon!
Tonight let's use our binoculars and telescopes to hunt down one of the best globular clusters for the northern hemisphere - M3. You will discover this ancient beauty about halfway between the pair of Arcturus and Cor Caroli - just east of Beta Comae. The more aperture you use, the more stars you will resolve. Discovered by Charles Messier on May 3, 1764, this ball of approximately a half million stars is one of the oldest formations in our galaxy. At around 40,000 light-years away, this awesome globular cluster spans about 220 light-years and is believed to be as much as 10 billion years old. To get a grasp on this concept, our own Sun is less than half that age!
Let's further our understanding of distance and how it affects what we see. As you know, light travels at an amazing speed of about 300,000 kilometers per second. To get a feel for this, how many seconds are there in a minute? An hour? A week? A month? How about a year? Ah, you're beginning to see the light! For every second - 300,000 kilometers.
M3 is 40,000 years away travelling at the speed of light. In terms of kilometers - that's far more zeros than most of us can possibly understand - yet we can still see this great globular cluster. Now let's locate M53 near Alpha Comae. Aim your binoculars or telescopes there and you will find M53 about a degree northeast.
This very rich, magnitude 8.7 globular cluster is almost identical to M3, but look at what a difference an additional 25,000 light-years can make to how we see it! Binoculars can pick up a small round fuzzy, while larger telescopes will enjoy the compact bright core as well as resolution at the cluster's outer edges. As a bonus for scopes, look one degree to the southeast for the peculiar round cluster NGC 5053. Classed as a very loose globular, this magnitude 10.5 grouping is one of the least luminous objects of its type due to its small stellar population and the wide separation between members - yet its distance is almost the same as that of M3.
Friday, May 11 - Tonight, start by locating 5th magnitude 6 Comae Berenices about three fingerwidths east of Beta Leonis. Remember this star! We are going on a Galaxy hop to a Méchain Discovery that is less than a degree west, and its designation is M98.
At magnitude 10, this beautiful Galaxy is a telescope-only challenge and a bit on the difficult side for small aperture. Long considered to be part of the Virgo Cluster, M98 is approaching us at a different rate than other cluster members, giving rise to speculation that it may simply be in the line of sight. Quite simply put, it has a blue shift instead of red! But considering that all these galaxies (and far fainter ones than we can see), are in close proximity leads some researchers to believe it is a true member by virtue of the extreme tidal forces which must exist in the area - pushing it toward us at this point in time, rather than away.
In a small telescope, M98 will appear like a slim line with a slightly brighter nucleus - a characteristic of an edge-on galaxy. To large aperture, its galactic disk is hazy and contains patchiness in structure. These are regions of newly forming stars and vast regions of dust - yet the nucleus remains a prominent feature. It's a very large galaxy, so be sure to use a minimum of magnification and plenty of aversion to make out small details in this fine Messier object!
Saturday, May 12 - It would well be worth getting up early this morning, as Uranus is occulted by the Moon. Be sure to check IOTA for times and locations. If nothing else, nearby Mars makes for an equally inspiring sight!
Tonight we'll return once again to 6 Coma Berenices and head no more than a half degree southwest for another awesome Galaxy - M99.
Discovered by Pierre Méchain on the same night as he found M98, this is one of the largest and brightest of the spiral galaxies in the Virgo Cluster. Recognized second after M51 for its structure, Lord Rosse proclaimed it to be 'a bright spiral with a star above.' It is an Sc class, and unlike its similarly-structured neighbors - it rotates clockwise. Receding from us at 2324 kilometers per second, its speedy retreat through the Galaxy fields and close pass to approaching M98 may be the reason that it is asymmetrical - with a wide arm extending to the southwest. Three documented supernovae have been recorded in M99 - in 1967, 1972 and 1986.
Possible in large binoculars with excellent conditions, this roughly 9th magnitude object is low surface brightness and requires clean skies to see details. For a small telescope, you will see this one as fairly large, round, wispy, and with a bright nucleus. But, unleash aperture if you have it!
For large scopes, the spiral pattern is very prominent and the western arm shows well. Areas within the structure are patchworked with bright knots of stars and thin dustlanes which surround the concentrated core region. During steady seeing, a bright, pinpoint stellar nucleus will come out of hiding. A worthy study!
Sunday, May 13 - Tonight we'll return again to 6 Comae and our hunt will be for the last of the three galaxies discovered by Méchain on that same wonderful night in 1781. You'll find it just a fingerwidth northeast of 6. Its name is M100.
M100 is one of the brightest member galaxies of the Virgo Cluster of galaxies - and its design is much like our own galaxy. From our point of view, we see M100 'face on,' and even Lord Rosse in 1850 was able to detect a spiral form. Thanks to its proximity to other galactic members, it has two grand arms in which recently-formed, young, hot, massive stars reside. Regardless of what seems to be perfect form, the nucleus shows that younger stars have formed more to the south side than the north. Perhaps interaction with its dwarf neighbors?
Achievable in binoculars as a soft round glow, and about the same in a small telescope, extensive photography has shown M100 to be far larger than previously believed - with a substantial portion of its mass contained in faint outer regions. The Hubble Telescope discovered over 20 Cepheids variables and one nova contained inside our spiral friend and was more able to accurately determine its distance at 6 million light-years. In addition, NASA's Ultraviolet Imaging Telescope has shown starburst and formation activity at the edges of M100's inner spiral arms.
Larger telescopes will see this galaxy's intense core region as slightly elliptical and sometimes reveal patchiness in the structure. With good sky conditions, even smaller scopes can reveal a spiral pattern, and this improves significantly with aperture. Be sure to look carefully because five supernovae events have been observed in this hot Galaxy - one as recently as February 2006!
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