Het Astronomie topic #1

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Moon to Hide Beautiful Star Cluster



During the next several years, skywatchers around the globe will periodically get a chance to watch the Moon pass in front of the most beautiful of all star clusters, the Pleiades. It will happen thirteen times in 2006 alone, beginning in January.

The easy-to-view events provide an excellent excuse to pull an old telescope out of the closet or buy a new one.

Astronomers refer to this phenomenon as an “occultation,” taken from the Latin word occult?re, which means, “to conceal.” In most cases, the Moon will hide a bright star or planet, but by passing in front of a cluster of stars like the Pleiades, many stars will be occulted within a span of a few hours.

Few star figures are as familiar as the Pleiades, known also as the Seven Sisters. Anyone having difficulty in recognizing various stars and constellations should start with this star pattern. This group looks at first glance to the naked eye like a shimmering little cloud of light.

But further examination will reveal a tight knot of 6 or 7 stars, though 11 or more have been recorded under excellent conditions. In long-exposure photographs, several stars in the cluster seem to be enveloped in clouds of dust, perhaps left over from the stuff of which they were formed. About 410 light-years away and some 20 light years across, the group may be no older than 20 million years. About 250 stars have been identified as members of this cluster.

The brightest stars glitter like an array of icy blue diamonds on black velvet. Or, as Tennyson wrote, they “glitter like a swarm of fireflies tangled in a silver braid.”

The last occultations of the Pleiades took place between 1986 and 1992. Since this cluster lies 4º north of the ecliptic, it can be occulted only when the ascending node of the Moon’s orbit is in the Pisces-to-Sagittarius part of the ecliptic. This situation repeats every 18.6 years, the time required for the ascending node to complete one circuit of the ecliptic. Hence, a new “season” of Pleiades occultations has begun that will continue until the year 2010.

Since the Pleiades are roughly twice as large as the Moon in apparent angular diameter only a part of the cluster can be hidden at any given moment; the Moon can never hide the entire cluster. The seven brightest Pleiads are (on average) around fourth magnitude. They are, in order of brightness: 1) Alcyone, magnitude +2.9; 2) Atlas, +3.6; 3) Electra, +3.6; 4) Maia, +3.8; 5) Merope, +4.2; 6) Taygeta, +4.3; 7) Pleione, +5.1.

It should also be noted, that in most cases, using binoculars or a telescope you’ll likely be able to watch perhaps up to several dozen occultations of the fainter stars in this cluster within a few hours.

In the table, below, is the complete list of Pleiades occultations through 2006, which will chiefly favor locations over the Northern Hemisphere. Note that each occultation will be visible only for a specific region of the Earth. In other areas, either the Moon will appear to miss the cluster or the event occurs during the daytime or when the Moon and Pleiades are below your local horizon. Even if your area is not in a favored position to see an occultation, you’ll still see the Moon and the Pleiades rather close to each other on the date in question. The date and universal time (U.T.) are given for the midpoint of each event. To convert to your time zone, keep in mind that U.T. that you will need to subtract five hours for Eastern Time, six hours for Central Time, seven hours for Mountain Time and eight hours for Pacific Time. When daylight saving time is in effect, subtract four hours for Eastern Time, five hours for Central Time, etc.

Also important: In some cases, after converting to your time zone, make sure you check to see if the occultation occurs on the previous calendar day. For example: 2006 April 2 at 01h U.T. converts to 2006 April 1 at 20h (9:00 p.m.) Eastern daylight time!

The percentage of the Moon’s disk that is illuminated is also provided. Remember that in the case of a waxing Moon, stars will disappear along the Moon’s dark limb and reappear along the Moon’s bright limb; with a waning Moon the stars will vanish first along the bright limb and pop back into view along the dark limb.

The very best Pleiades occultations will be those involving a crescent Moon, where the Moon’s light is not overly bright. In addition, Earthshine may also be evident as a faint grayish-blue illumination of the dark part of the Moon’s disk. This dim light is produced by sunlight striking the “dark” side of the Moon after first being reflected from the Earth’s surface, clouds and atmosphere. This effect will give the Moon an almost 3-D quality and will only serve to enhance the overall view. The April and July occultations which favor eastern North America, should be especially striking and Night Sky will provide detailed outlooks as we draw nearer to both of these events.

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Hubble Sheds Light on Dark Matter

Astronomers don’t know what it is, but every now and then they find more evidence of dark matter and pin down where the mysterious stuff resides.

A new project that recycled Hubble Space Telescope images has mapped the invisible dark matter with unprecedented detail. Researchers focused on two galaxy clusters that are so far away, and their light has taken so long to get here, that they are seen as they existed when the universe was about half its present age.

The observations provide additional evidence supporting a leading theory that galaxies form in cosmic webs, with regular material and dark matter condensing into nodes something like water drops gather at intersections of spider silk.

You can also think of it as froth gathering on the tops of ocean waves, said study team member Myungkook James Jee at Johns Hopkins University.

Strange stuff

Dark matter is thought to exist because without it, galaxies would fly apart for lack of gravitational glue. However mapping something that can’t be seen is problematic.

"It is very challenging to verify the simulation results observationally, because dark matter does not emit light," Jee said.

The trick is to look for subtle distortions in the images caused by gravitational lensing, in which the shapes of very distant galaxies are warped by dense concentrations of matter between us and the galaxies. The matter, which is not visible, bends the light with its gravity, and that reveals its presence.

"The images we took show clearly that the cluster galaxies are located at the densest regions of the dark matter haloes, which are rendered in purple in our images," Jee said.

The results are detailed in the December issue of Astrophysical Journal.

Dark matter makes up about 90 percent of the universe’s total. Theory holds that it should gather with regular matter, because of their mutual effects of gravity. The new observations support that idea, Jee said.

The work also supports the notion that dark matter is not made of particles that can collide. It’s not known if dark matter involves particles at all, but if so, they must be collisionless.

"Collisionless particles do not bombard one another, the way two hydrogen atoms do," Jee said. "If dark matter particles were collisional, we would observe a much smoother distribution of dark matter, without any small-scale clumpy structures."

The two clusters each contain more than 400 galaxies.

"These images were actually intended mainly to study the galaxies in the clusters, and not the lensing of the background galaxies," said co-researcher Richard White of the Space Telescope Science Institute, which operates Hubble for NASA. "But the sharpness and sensitivity of the images made them ideal for this project. That's the real beauty of Hubble images: They will be used for years for new scientific investigations."

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Op maandag 19 december 2005 10:58 schreef Haushofer het volgende:

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Ik ga gewoon even ordinair linken naar één van mijn topics over de kosmologische constante. Als we het dan toch over donkere materie hebben

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The Big Bangs for Astronomers in 2005

PHOENIX, Ariz. -- The past year in space science and astronomy was dominated by debate and some tantalizing near-findings.

A hangover of heady Mars discoveries festered while astronomers on the ground obtained evermore intimate glimpses of the outer solar system and the solar neighborhood but stopped short of declaring agreement on what they’d found. To punctuate that ambiguity with some stark clarity elsewhere, NASA smacked a comet and found it to be all fluff.

Among the highlights:

The 10th Planet?

You might think the discovery of an object larger than Pluto orbiting the Sun would automatically be hailed as the long-sought 10th planet. Caltech’s Mike Brown and his colleagues figured as much. Not so fast, many astronomers said. This new world is one of perhaps thousands out there that await discovery. Will we call them all planets? Should Pluto even be considered a planet? In a weird twist to the debate, Brown suggests we all ignore the scientific debate and let culture decide. One has to wonder if that’s the sort of ambiguity science ought to promote.

Signs of Life on Mars?

This story extends back to last year and looks like the sort of mystery that’ll keep scientists scratching their heads for years to come. The air of Mars seems to contain pockets of methane in doses that should not exist. Perhaps it’s the belchings of subsurface microbes, European astronomers said early this year. They support that view with new evidence for blocks of underground ice in the same region as the methane, based on observations by ESA’s Mars Express. The ice could be supplying the precious liquid water needed to support the biology, they figure. Other astronomers think the reasoning is very speculative, however.

Super-Earth Discovered

Astronomers expect to eventually find many Earth-sized planets around other stars. But technology can’t spot such small objects yet. Pushing the limits of existing methods, Paul Butler of the Carnegie Institution of Washington and colleagues detected a world just 7.5 times the mass of Earth orbiting another star and said it must be rocky. This year marked the 10th anniversary of the discovery of the first extrasolar planet around a normal star, and astronomers have gathered enough data on about 150 planets since then to say, in the words of planet-hunting guru Geoff Marcy of the University of California, Berkeley, "I imagine most stars have terrestrial planets. It seems hard not to form them."

Birth of a Black Hole

An explosion 2.2 billion years ago, whose light just arrived at Earth this year, was detected and then monitored by an unprecedented array of telescopes on the ground and in space. The event prompted a furious exchange of e-mails. Within moments, the scientists, led by Neil Gehrels of NASA’s Goddard Space Flight Center, suspected they had seen the birth of a black hole as it happened (well, except for that previously mentioned time lag of 2.2 billion years). The event was triggered by the merger of two neutron stars, the thinking goes.

First Photo of an Extrasolar Planet?

A series of announcements about the possible first picture of a planet around another star ended up in a debate that has yet to be resolved. In 2004 a team based at the European Southern Observatory (ESO) said they had made what they said was likely the first picture of an extrasolar planet. The object, 2M1207b, appeared bound to a young but failed star known as a brown dwarf sitting about 200 light-years from Earth.But it was also possible that 2M1207b was instead a distant background object.

This past April, Ralph Neuhaeuser of the Astrophysical Institute & University Observatory said his team had made the first confirmed picture of a planet around another star called GQ Lupi, some 400 light-years away. Both pictures are real, but astronomers can’t agree on the masses of the objects in the images or, for that matter, how to state the difference between large planets and small stars. We’ll have to wait for history to tell us if this was a big story or not.

Protecting Ourselves

Some day, scientists have been telling us for some years now, we’ll have to deal with an incoming asteroid or comet that would destroy civilization at worst or wipe out a city at least. Big impacts have occurred before, and there will be more. But we don’t know enough about space rocks and their composition to plan properly for deflecting or destroying such a menace. Turnabout proved to be fair play when NASA’s Deep Impact mission slammed a probe into Comet Tempel 1 on the 4th of July.

The upshot? This comet was fluffy, unlike others that have been studied up close. Meanwhile, a group of scientists and astronauts, led by Russell Schweickart, a former Apollo astronaut, prodded NASA to visit asteroid Apophis, which has a slight chance of hitting us a few decades hence. NASA’s response: A purely scientific mission might be considered, but we have plenty of time to mount a diversion if further observations show this thing would really hit.

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Op woensdag 21 december 2005 22:53 schreef -CRASH- het volgende:
interessante software voor de amatuer astro-fotografen onder ons....

Kost wel een paar centjes..... $ 299.00
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Gedetailleerd beeld van centrum melkwegstelsel

Astronomen van de universiteit van Californie in Los Angeles en hun collega's hebben de eerste gedetailleerde foto van het centrum van ons melkwegstelsel gemaakt, inclusief het gebied rondom het supermassieve zwarte gat. Hiervoor werd een nieuwe laser gebruikt bij het W. M. Keck observatorium in Hawaii.

"Alles is veel duidelijker nu," aldus Andrea Ghez, professor in fysica en astronomie aan de universiteit en leider van het onderzoeksteam. "We hebben een laser gebruikt om het beeld van de telescoop te verbeteren. Dit is een spectaculaire doorbraak, want nu kunnen we zwarte gaten nog beter begrijpen."

Astronomen zijn gewend aan het werken met wazige foto's, wat komt door de atmosfeer van de aarde. Een laser kan echter deze atmosferische verstoringen corrigeren en hierdoor ontstaan heldere foto's. Deze nieuwe technologie, wat Laser Guide Star adaptieve optiek wordt genoemd, zal leiden tot nieuwe ontdekkingen in de kosmos.

"We zijn al jaren op zoek naar technieken om de verstoringen in de atmosfeer te 'verslaan' en om hoge resolutie foto's te produceren," zei ze. "We zijn blij dat de eerste observaties met de laser succesvol zijn verlopen."

Hieronder de foto's van de kern van ons melkwegstelsel. Links de nieuwe foto en rechts de foto zonder gebruik te maken van de laser. Zie jij het verschil?

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Op donderdag 22 december 2005 18:17 schreef Kered het volgende:

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Kunnen ze niet gewoon hubble gebruiken?

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New Moons and Rings Found at Uranus

Astronomers have discovered new rings and small moons around Uranus and found surprising changes in satellite orbits around the giant planet.

NASA's Hubble Space Telescope photographed a pair of previously unknown rings. The largest is twice the diameter of the planet's previously known rings. The new rings are so far from the planet that they are being called Uranus's "second ring system."

Hubble also spotted two small satellites. One shares its orbit with one of the newly discovered rings. Most surprisingly, the orbits of Uranus's family of inner moons have changed significantly in the last decade, the new data reveal.

Collectively, the discoveries mean Uranus has a densely packed, rapidly changing, and possibly unstable dynamical system of orbiting bodies.

"The new discoveries dramatically demonstrate that Uranus has a youthful and dynamic system of rings and moons," says Mark Showalter of the SETI Institute. "Until now nobody had a clue the rings were there, we had no right to expect them."

Since dust in such an orbit is expected to be depleted by spiraling away, the rings must be continually replenished with fresh material. Showalter and collaborator Jack Lissauer of the NASA Ames Research Center propose that the outermost ring is replenished by a 12-mile-wide companion satellite, named Mab, which they first saw in 2003 using Hubble. Meteoroid impacts continually blast dust off the surface of Mab, and the dust then spreads out into a ring around Uranus.

Other small moons are linked to rings, including Amalthea at Jupiter, Pan at Saturn, and Galatea at Neptune.

Mab's ring receives a fresh infusion of dust from each impact. In this way, nature "balances the books" by keeping the ring supplied with new dust while older dust spirals away or bangs back into the moon, the thinking goes.

Showalter and Lissauer have measured numerous changes to the orbits of Uranus's inner moons since 1994.

“This appears to be a random or chaotic process, where there is a continual exchange of energy and angular momentum between the moons," Lissauer said. "The changes in the last ten years are small, but the thing about chaos is that small changes build up exponentially with time. As a result, this suggests that the entire system is orbitally unstable."

The moons may begin to collide in a few million years, Lissauer figures.

Perhaps the most unstable moon of all is tiny Cupid, whose orbit brings it within 500 miles of the moon Belinda.

Showalter and Lissauer propose that their discovery of a second ring, which orbits closer to the planet than the new outermost ring, provides further evidence for collisional evolution of the system. This ring orbits in the midst of the moons but has no visible body to re-supply it with dust.

"This ring may be the telltale sign of an unseen belt of bodies a few feet to a few miles in size," Showalter said. He proposes that the collisional disruption of a moon in Uranus's past could have produced the debris ring they now observe.

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Op vrijdag 23 december 2005 12:34 schreef -CRASH- het volgende:
Moet je ook ff de foto's erbij plaatsen Quarks

[afbeelding]

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De planeten in 2006



Venus, Mars and Saturn light the cold, frosty evenings of winter as the New Year opens up, but 2006 will be hardly a week old when Venus plunges rapidly down into the sunset. Mars, meanwhile, fades into the distance.

As warmer weather approaches, Saturn takes over to dominate the milder evening skies of late winter and early spring, only to be replaced in turn by Jupiter later in the spring and summer. Meanwhile, speedy Mercury will pass in front of the Sun in early November, then joins Mars and Jupiter to form a tight triangle in the dawn skies of early December.

Sound like a busy year for planet watching? Let's take a look at the visibility of each of these worlds during 2006.

MERCURY: Mercury usually appears as a bright "star" with a yellowish or ochre hue. At its best evening apparitions, it can be found almost directly above where the Sun has set, being visible for up to 90 minutes after sundown. As viewed from the Northern Hemisphere, such an opportunity will come between Feb. 10 to March 3. It will also be positioned to the north of a razor-thin crescent Moon on the evening of February 28.

During its best morning apparitions, you'll find it positioned almost directly above where the Sun will rise up to 90 minutes prior to sunup. Such an occasion will come between Nov. 18 to Dec. 9 and it will appear to ride well to the north a slender sliver of a crescent Moon on the morning of November 19. On Nov. 8, a transit of Mercury will take place, with the planet appearing in silhouette as a tiny black dot on the Sun's disk. This event will be visible from the Americas, the Pacific Ocean, Australia, New Zealand and eastern Asia.

VENUS: Always appears brilliant, and shines with a steady, silvery light. It starts 2006 very low in the west-southwestern evening sky at dusk for the first several days of January. It then passes roughly between the Sun and the Earth (inferior conjunction) on Jan. 13 and makes its transition into the morning sky.

You'll find it during the final week of January, low in the east-southeast sky at the first light of dawn and it will continue to be a prominent morning object right on through the end of August. It will then be hidden again by the bright solar glare almost through the balance of the year. Passing through superior conjunction on Oct. 27, it will then return to the evening sky, though not likely readily visible for most until the waning days of December. During late January and through much of February, it will resemble a beautiful crescent in steadily held binoculars and telescopes.

Venus will reach its greatest brilliancy in the morning sky on Feb. 17. Venus will appear to pass very close to Saturn on the morning of Aug. 27; the planets will appear low to the eastern horizon and separated by only about a half-degree (the apparent width of the Moon).

MARS: Shines like a star with a yellowish-orange hue. This will evolve into an "off year" for Mars, although it will be just coming off a splendid opposition during mid-autumn of 2005. It will appear brightest in 2006 on New Year's Day, still glowing brilliantly at magnitude –0.6 in the constellation of Aries and outshining all the stars in the sky with the exception of Sirius and Canopus. It will then be 72 million miles from Earth, but it will also be receding from us each night thereafter and hence will be getting progressively fainter.

By March 1, it will appear more than 3½ times dimmer and by May 9 it will have fallen into the ranks of a second magnitude object. Mars will pass just over one-half degree from Saturn in the evening sky of June 17. A month later, it is all but gone from view, becoming too deeply immersed in the solar glare to be seen. It will be in conjunction with the Sun on Oct. 23, becoming a morning object. Not until about the middle of December will it emerge from the bright morning twilight.

JUPITER: will appear as a brilliant "star" with a silver-white luster in the constellation of Libra, the Scales. It will be primarily a late-night/early morning object from January through April.

By May and June it will be visible most of the night and will continue to be a convenient evening object through the end of October. It is at opposition to the Sun on May 4. It will disappear into the Sun's glow in early November and will again become visible in the morning sky during early December.

SATURN: Usually shines like a yellowish-white "star" of moderate brightness. It will be primarily a late-night/early morning object through much of January. By late January into February it will be visible most of the night and will continue to be a convenient evening object through the middle of July. It is at opposition to the Sun on Jan. 27 and will also have two close encounters with other naked-eye planets in 2006.

It will pass just over one-half degree from a much-dimmer Mars on the evening of June 17 and will lie a similar distance from the much-more dazzling Venus on the morning of Aug. 27. Saturn is located within the relatively dim stars of Cancer, the Crab. On February 2 and again on June 5, Saturn will be situated just below the beautiful cluster of stars popularly known as the "Beehive." The famous ring system is visible in telescopes magnifying over 30-power.

From mid-March until the beginning of May, the rings will be tilted at a 20º angle toward Earth. You should take full advantage of this circumstance, because, we won't see the rings tipped 20º or more to our line of sight again until the year 2014!

URANUS: can be spied with the unaided eye under a clear, dark sky. However, it is more easily seen in binoculars. At magnitude +5.7, it is located in Aquarius and is at opposition to the Sun on Sept. 5.

NEPTUNE: is an 8th magnitude object visible in binoculars and in 2006 resides in Capricornus, the Sea Goat. It arrives at opposition on August 11.

PLUTO: the smallest and most distant planet is, at magnitude 14 (about 900 times fainter than the faintest star visible to the unaided eye), the most difficult to observe. You'll need a very dark sky, at least an 8-inch telescope and a finder chart to locate it. In the constellation of Serpens, the Serpent, it's at opposition on June 16.

The Highlight of 2006: A Planet Trio

Jupiter, Mercury and Mars will engage in a most intriguing pre-Christmas gathering, very low in the east-southeast sky during the second week of December. The best time to look will be around 6:30 a.m. local time. Unfortunately, the low altitude, plus this gathering's proximity to the Sun likely will render Mars invisible (or nearly so) to the unaided eye. Binoculars are strongly recommended. In contrast, Mercury and Jupiter should be more readily visible to the eye with only slight difficulty, as they will shine much brighter than Mars.

The trio will be most compact—fitting within just a 1-degree circle—on Dec. 10. On this morning, the three planets will resemble a compact arrowhead pointing west, with Mars at the arrowhead.

There will also be separate conjunctions between Mercury and Mars (Dec. 9), Mercury and Jupiter (Dec. 10) and Mars and Jupiter (Dec. 11). Also, for binocular viewers on the morning of Dec. 10, Mercury will appear to lie very close below and to the right of the second magnitude star Graffias in Scorpius, the Scorpion.

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Op dinsdag 3 januari 2006 20:16 schreef -CRASH- het volgende:

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En nu de bewolking nog....

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Space Tornado! Cosmic Front Packs a Punch

WASHINGTON, D.C.—High-energy particles spewing out of a young star in a nearby stellar nursery are plowing through interstellar clouds and creating a giant spiral structure in space that looks like a glowing, rainbow-colored tornado, scientists said today.

The star spewing the particle jet lies 480 light-years away in a star-forming region known as Chamaeleon I.

In a photograph taken with NASA’s Spitzer Space Telescope, that star is actually not visible because it is located off the upper edge of the image.

The luminous tornado-shaped structure is known as a Herbig-Haro object and estimated to be about 0.3 light years, or nearly 2 trillion miles, long and shows up in the infrared.

Herbig-Haro objects are formed when highly energized particles—usually electrons and protons—are ejected from a young star and collide with nearby clouds of interstellar dust and gas. The jet particles stream out of the stars at speeds of more than 100 miles per second and heat the surrounding clouds to an infrared glow that can be detected.

Astronomers have known about Herbig-Haro objects for decades but have never observed one with this unique spiral structure; this particular particle jet is known as Herbig-Haro 49/50, or HH 49/50.

“I’ve never seen anything quite like this one,” said Giovanni Fazio, a physicist at the Harvard-Smithsonian Center for Astrophysics (CfA) who was not involved in making the discovery.

“We were really quite stunned by it,” he told SPACE.com.

As particle jets move through the clouds, they create triangular shockwaves, similar to the wake left behind a speeding boat.

The reason the tornado appears multi-colored is because particles at the tip of the jet are more excited than those nearer to the star where they are emanating from. The excited particles radiate short-wavelength emissions, which in this color-coded image appear blue; emissions from particles near the wide base of the jet are longer and appear red.

Scientists aren’t sure what is behind HH 49/50’s unique spiral shape. One hypothesis is that magnetic fields in the region are somehow twisting the particle jets; another idea is that the shockwaves are creating eddies in the dust clouds which then glow and become visible.

Scientists also don’t know whether the star at the center of the image is associated with HH 49/50 or not.

If it is, then it could mean that the image actually shows HH objects from two stars colliding with each another. The more likely option, scientists say, is that the center star is actually located much further away and only looks like it’s associated with HH 49/50 because it happened to be in Spitzer’s line of sight when the image was taken.

The team that made the discovery was headed by John Bally of Colorado State University. It announced today at the 207th meeting of the American Astronomical Society.

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Op woensdag 18 januari 2006 10:40 schreef MuzzleFlash het volgende:
Hier een paar Google Maps shots van Cape Canaveral:

De lanceer site van de Atlas V (Launch Pad 41), waar het allemaal om draait.

Verticle Assembly Building

Space Shuttle launch site

Niet zeker, maar dit is als het goed is de Apollo 11 Launch Site

Argh. Imageshack

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Today's planned launch of an Atlas V carrying NASA's New Horizons spacecraft has been delayed for at least one more day. The Johns Hopkins University's Applied Physics Laboratory, which operates the spacecraft and is managing the mission, experienced a power outage early this morning that has not yet been resolved. Launch is now set for Thursday, Jan. 19, during a window extending from 1:08 p.m. - 3:07 p.m. EST.

As the first spacecraft to visit Pluto and its moon Charon, New Horizons looks to unlock one of the solar system's last, great planetary secrets. After launch aboard an Atlas V, the New Horizons spacecraft will cross the entire span of the solar system and conduct flyby studies of Pluto and its moon, Charon, in 2015. The seven science instruments on the piano-sized probe will shed light on the bodies' surface properties, geology, interior makeup and atmospheres.

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Op donderdag 19 januari 2006 17:30 schreef whosvegas het volgende:
De new horizons missie gaat gelanceerd worden naar Pluto
Gister lukte het niet, vandaag ziet het er goed uit!
http://www.astrostart.nl/index.php?subaction=showfull&id=1137676182&archive=&start_from=&ucat=105&

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Op donderdag 19 januari 2006 19:03 schreef -CRASH- het volgende:
wha..... no go

wie heeft er aan de sealings gezeten

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Op donderdag 19 januari 2006 19:23 schreef -CRASH- het volgende:

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en dat is ook alweer uitgesteld

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Op donderdag 19 januari 2006 19:31 schreef -CRASH- het volgende:

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en weer.... nu naar 19:50

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Op donderdag 19 januari 2006 19:42 schreef -CRASH- het volgende:

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weet ik dat de T- erbij zit maar uitstel is er maar ze zeggen new launchtime 1:55

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Op donderdag 19 januari 2006 19:46 schreef -CRASH- het volgende:

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ze blijver er tijd bijzetten.. nu weer 5 minuten

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Op donderdag 19 januari 2006 19:58 schreef whosvegas het volgende:
Het aftellen is begonnen, nog 2 minuten!

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Op donderdag 19 januari 2006 20:03 schreef whosvegas het volgende:

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Was een beetje laat

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Op donderdag 19 januari 2006 20:10 schreef -CRASH- het volgende:
Main Engine Cutof 30 secs

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Op donderdag 19 januari 2006 20:17 schreef -CRASH- het volgende:

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Dit is weer een nieuw soort vlucht.
Deze is snel tegenover de oude vluchten.

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Op donderdag 19 januari 2006 20:21 schreef -CRASH- het volgende:

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Sja zullen flink wat users bijgekomen zijn sindts de laatste lancering.

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Op donderdag 19 januari 2006 20:45 schreef -CRASH- het volgende:

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En weer een ruimtetuig dat verdergaat op RTG

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Op donderdag 19 januari 2006 20:54 schreef -CRASH- het volgende:
Eindelijk dat die vuurpijl afging.....

Is het toch nog een beetje een leuke
verjaardag geweest vandaag.

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Op donderdag 19 januari 2006 21:01 schreef -CRASH- het volgende:

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THNX
Ze zegggen het
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zal ie ookwel altijd blij zijn
dat heel nederland de vlag uithangt
voor de jarige van vandaag.

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Op donderdag 19 januari 2006 21:28 schreef -CRASH- het volgende:

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er is er ook nog 1 van de oranjes jarig... Prinses Magriet
Dus dan wordt de vlag uit gehangen.


Psssst beetje oftopic bezig
Maar nu verder als astronomie topic

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Strange Setup: Andromeda's Satellite Galaxies All Lined Up



An unusually high number of galaxies are aligned along a single plane running through the center of the giant Andromeda galaxy. Scientists don’t have a theory to explain why.

Galactic cannibalism or dark matter may be responsible, researchers say.

The Andromeda galaxy is located at a distance of 2.5 million light-years away and is the nearest spiral galaxy to the Milky Way. Like our own galaxy, Andromeda is surrounded by numerous dwarf galaxy satellites. Many of these satellites are within 1.3 million light-years or less of the galaxy’s main disk.

Using the Hubble Space Telescope, Eva Grebel and Andrew Koch from the University of Basel in Switzerland found that nine out of Andromeda’s fourteen dwarf galaxy satellites reside in a single plane. The plane is about 52,000 light-years wide and is aligned perpendicular to Andromeda’s own galactic plane, within which the galaxy’s stars orbit about the center.

That nearly 80 percent of Andromeda’s satellite galaxy mass is located within a single plane is highly unusual and can’t be accounted for by traditional theories of galaxy formation, Grebel said.

The finding was announced recently at a meeting of the American Astronomical Society.

The Milky Way was found to contain two similar planes of satellite galaxies in the late 1980s, but with nothing to compare them to, astronomers couldn’t tell if such planes were a general property of galaxy formation or whether they were just a statistical fluke.

"One of the open questions was always ‘Do such planes of satellite galaxies exist around other galaxies?’" Grebel said. "If they do, it might indicate that it’s more than just chance."

The researchers aren’t sure what might be responsible for the strange alignment but they offered two possible scenarios.

Galactic Cannibalism

Perhaps long ago Andromeda swallowed a nearby orbiting galaxy but did a messy job of it; the galactic crumbs from that meal became Andromeda’s satellite dwarf galaxies. Such instances of galactic cannibalism are common and are believed to play a major role in galaxy formation.

"If this scenario were correct, we would expect these satellites to maintain the original orbit from the original galaxy form which they came," Grebel explained. Early results from computer models suggest that such a scenario is physically possible.

But it might be several years before this hypothesis can be confirmed, since accurate orbital measurements for Andromeda’s satellite galaxies are extremely difficult due to their distance, she added.

Dark matter stream

Another intriguing possibility is that the satellite galaxies are actually embedded in a stream of hypothetical dark matter flowing between two massive objects.

The plane containing Andromeda’s satellite galaxies points toward two such objects: M33, a spiral galaxy located 0.7 million light-years away from Andromeda and M81, a cluster of about 30 galaxies that is 11 million light-years away.

It could be that the satellite galaxies are gravitationally attracted to these streams of dark matter and clumping around them, giving the appearance of being aligned along a single, wide plane.

Grebel stressed that at this point, both of these scenarios are just speculation.

"We have no proof whether any of these is actually true," she said.

It may turn out that the alignment is due to chance after all or that another explanation entirely may be responsible.

Michael Turner, a cosmologist at the University of Chicago who was not involved in the study, found the results intriguing.

"It’s getting at this very simple question: how did our backyard get assembled?" Turner said.

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Op maandag 23 januari 2006 22:29 schreef -CRASH- het volgende:

[..]

DAWN gaat niet door.....
[..]

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Falcon 1 Maiden Flight Update: Posted January 9, 2006

The new launch time is February 8 at 4:30 p.m. California time with Feb. 9 as a backup day.

Launch Viewing for Media

On launch day, a live feed of this historic launch will be available to the media at SpaceX Headquarters in El Segundo, CA – five minutes south of Los Angeles International Airport. The address is 1310 East Grand Avenue El Segundo, CA 90245.

Media check-in will begin at 3:30 p.m. PST on launch day. The launch time is expected to be 4:30 p.m. Food and beverages will be made available. To attend the launch viewing event, media must contact SpaceX at 310-414-6555 ext 283 or news@spacex.com. Please provide full name, affiliation, citizenship and date of birth.

Media unable to attend may listen and ask questions through a telephone conference line that will be moderated throughout the launch window. Questions from media will be taken at designated intervals.

Check-in for the media phone line will begin at 3:30 p.m. PST with coverage starting at 4:00 p.m. Accredited media can contact SpaceX at 310-414-6555 ext 283 or news@spacex.com for the access information to join the launch media event via phone.

Still photos and video of the launch will be made available on www.spacex.com within hours of the launch.




Falcon 1 on Launch Pad in Kwajalein

SpaceX Launch Overview

On launch day, the Falcon 1 rocket will begin its journey to orbit, accelerating to 17,000 mph (25 times the speed of sound) in less than ten minutes. Designed from the ground up by SpaceX, Falcon 1 is a two stage rocket powered by liquid oxygen and purified, rocket grade kerosene. On launch day, Falcon 1 will launch into the history books for several notable reasons:

* It will be the first privately developed, liquid fueled rocket to reach orbit and the world\\\\\\\\\\\\\\\'s first all new orbital rocket in over a decade.
* The main engine of Falcon 1 (Merlin) will be the first all new American hydrocarbon engine for an orbital booster to be flown in forty years and only the second new American booster engine of any kind in twenty-five years.
* The Falcon 1 is the only rocket flying 21st century avionics, which require a small fraction of the power and mass of other systems.
* It will be the world\\\\\\\\\\\\\\\'s only semi-reusable orbital rocket apart from the Shuttle.
* Most importantly, Falcon 1, priced at $6.7 million, will provide the lowest cost per flight to orbit of any launch vehicle in the world, despite receiving a design reliability rating equivalent to that of the best launch vehicles currently flying in the United States.

The maiden flight will take place from the Kwajalein Atoll of the Marshall Islands. The customer for this mission is DARPA and the Air Force. The payload will be FalconSat-2, part of the Air Force Academy’s satellite program that will measure space plasma phenomena, which can adversely affect space-based communications, including GPS and other civil and military communications. The target orbit is 400 km X 500 km (just above the International Space Station) at an inclination of 39 degrees.

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Falcon 1 Maiden Flight Update:

New Launch Time

As an additional reliability measure, SpaceX will conduct a full test of vehicle systems, including initiating the flight countdown autosequence and briefly firing the main engine on the launch stand. This test will take place Thursday, February 9 (California time). If no flight critical anomalies are detected, launch will take place on Friday, February 10. The launch window on Friday is 12 p.m. - 7 p.m. (California time).

Following the problem on Dec. 19, we flew a whole new first stage to Hawaii via C-5 just in time to catch the barge from there to Kwaj a few days before New Year's Eve. The new stage should arrive at Kwaj in about a week, whereupon we will switch it out with the damaged unit, which will be sent back to California for repair. The repair is not particularly difficult or expensive, but can only be done properly in a factory setting.

What Was the Problem?

As previously reported, we traced the problem to the failure of an electronic component in one of the first stage fuel tank pressurization valves. Although we have triple redundant pressure sensors and dual redundant pressurization valves, when this component shorted, it caused the valve controller board to reboot, effectively eliminating the redundancy.

This is the first time in 3.5 years of hard testing that we have ever seen this happen. Moreover, the component in question has a cycle life and power rating far in excess of the theoretical load that it should see. To address this specific problem, we are replacing the component with one that has a quasi-infinite lifespan and taking a few other steps that will isolate any issue with this component if it goes wrong in the future.

However, as I mentioned in an earlier update, we are not simply going to address this particular point problem and then merrily jump back into a countdown sequence. Throughout January, the SpaceX team will be doing another full review of vehicle systems, including propulsion, structures, avionics, software and ground support systems. We will be conducting additional engine tests, stage separation tests and avionics tests to once again attempt to flush out any issues. Even if we find nothing, the exercise is worthwhile.

Wind Delays Suck (Literally)

It is worth noting that we would have caught the problem without any damage to the vehicle if we had entered the final countdown sequence as planned. The sucked in tank damage only occurred because we partly drained the fuel tank due to the hold for high winds.

High winds are not a limitation of the rocket, which is designed to be essentially "all weather" and handle ground winds in excess of 50 mph (watch out for flying coconuts!). The ground winds limitation is actually due to the need to avoid a collision with the launch stand hold down arms, which grab the rocket at the base of the fuel tank, as the rocket lifts off.

To alleviate this problem, we have redesigned the launch stand so that the hold down arms retract out of the way on liftoff, activated by a breakwire. This gives us something very close to 100% winds availability from Kwaj. The retraction force is low, so even if there were an early activation of the actuator, it would not damage the rocket.

Another bothersome problem is the high rate of liquid oxygen (LOX) boiloff. This is not surprising when LOX is at -300F and there is a stiff wind impinging on the vehicle at 85F. To minimize boiloff, we will wrap the LOX tank in low cost cryo insulation attached with velcro straps that tear away on liftoff.

Lessons Learned on F1 Apply to F9

The challenges to date I think vindicate the strategy of building a small launch vehicle before a large one. If we had started out with an F9 class vehicle, the cost of every mistake would be multiplied by as much as an order of magnitude. As it is, we are able to overcome problems comparatively quickly and cheaply.

With the benefit of lessons learned on F1, it is taking far less time, effort and money to create F9. Despite the distraction of the F1 launch countdowns, I still anticipate a flight F9 first stage firing later this year and a maiden launch in late 2007.

Great Expectations

Those familiar with the launch business will know that countdown scrubs are a way of life. It's often said that the safest time to schedule your vacation is around launch day and that's true more often than not. Even rockets that have launched hundreds of times from launch pads that are in heavy use have multiple scrubs. Not too long ago, there was a Titan launch that had eleven scrubs and Delta launch that had six.

Reasons range from hard to avoid technical glitches, like the Shuttle fuel sensor malfunction on its last launch attempt, to silly false alarms. A Titan countdown was once aborted when someone spotted a "bag of suspicious liquid" on the mobile service tower. It turned out that the latrine had simply been a bridge too far for one of the technicians.

Given that Falcon 1 is an all new rocket and is launching from an all new launch pad on a remote tropical island, countdown scrubs in the first few attempts were very likely. As it is, we have had one abort due to a launch pad issue and one due to the rocket. If this next attempt succeeds in getting to t-zero, SpaceX will be reasonably fortunate in the scheme of things.

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New Horizons on Track for Jupiter

A spacecraft headed for the Solar System’s edge has aimed itself at the planet Jupiter in a long-distance slingshot on toward Pluto.

NASA’s New Horizons probe fired its thrusters in two brief maneuvers – one on Jan. 30 and an earlier event on Jan. 28 – for a total speed change of about 40 miles per hour (or about 18 meters per second). Launched on Jan. 19, New Horizons carries seven primary instruments on a mission to study Pluto, its moons and the icy Kuiper Belt objects beyond the ninth planet.

A third, final trajectory maneuver is set for Feb. 18, but New Horizons launch placed it so close to its flight path that the probe has managed save much more hydrazine propellant for later use than expected, APL spokesperson Mike Buckley told SPACE.com. The probe will swing past Jupiter on Feb. 28, 2007 and use the planet’s gravity as a boost toward Pluto, he added.

“We’re on our way to an exciting Jupiter encounter and a date with destiny at Pluto,” said New Horizons principal investigator Alan Stern, of the Southwest Research Institute in Boulder, Colorado.

Stern will celebrate the centennial anniversary of the birth of astronomer Clyde Tombaugh, who discovered Pluto in 1930, on Feb. 4 with a presentation at the University of Kansas in Lawrence, Kansas.

Tombaugh discovered Pluto on Feb. 18, 1930 at Flagstaff, Arizona’s Lowell Observatory. The University of Kansas’ Clyde Tombaugh Observatory is named after the astronomer, who died in 1997.

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Shining Light on Dark Matter

By Daniel Clery
ScienceNOW Daily News
7 February 2006

Researchers say they have for the first time measured physical properties of dark matter, the invisible stuff that makes up much of the universe. A team led by Gerry Gilmore of the Institute of Astronomy at Cambridge University detected a core of dark matter of uniform size and temperature inside dwarf galaxies. The finding runs counter to current dark matter theories, in part because the temperature measured was warmer than popular theories predict.

Astronomers have known for decades that the visible stars in a galaxy don't have enough gravity to hold it together. Large amounts of dark matter must make up the balance. But scientists have been stumped in their efforts to locate or describe it. The most popular theory suggests that dark matter consists of massive exotic particles that do not interact with normal matter except through gravity. It also holds that the particles are slow and cool. While this model fits most galaxies, it also predicts many more small galaxies than are known.

For the past 3 years, Gilmore and his team have been using giant telescopes to map the positions and velocities of thousands of stars in 10 minigalaxies around the Milky Way. Gilmore hadn't intended to make a big announcement, but on 3 February he appeared with others at a press conference in London to publicize the work of the European Southern Observatory (ESO), one of whose telescopes the team is using. At the press conference, Gilmore said the team had found the same volume of dark matter in each galaxy. The dark matter was about 1000 light-years across and had an even density equivalent to four hydrogen atoms per cubic centimeter.

The new results suggest that dark matter at the center of small galaxies is more spread out and warmer than was thought. The particles appear to have a velocity of 9 kilometers per second, and Gilmore believes that they interact with one another via some unknown force to spread out evenly. The nature of dark matter particles themselves remains one of the biggest mysteries of physics.

Scientists are reacting cautiously until they learn more about Gilmore's find, which he intends to submit to Astrophysical Journal. But the claim alone "will generate a lot of excitement," says cosmologist Robert Nichol of the University of Portsmouth, U.K. Mario Mateo of the University of Michigan, Ann Arbor, who also studies dwarf galaxies, was surprised by the density of dark matter Gilmore found. Still, he says, it's "pretty amazing" that although scientists can't see it or measure it, "we can start talking about constraining the nature of dark matter."