Tag: jupiter (page 2 of 9)

Jupiter May Be Behind The Mysterious ‘Gaping Hole’ In Our Solar System

Excerpt from huffingtonpost.comWhen astronomers began studying other solar systems in the Milky Way galaxy back in the 1990s, they noticed something peculiar: most of these systems have big planets that circle their host stars in tight orbits, a fin...

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New spin on Saturn’s peculiar, err, spin

 Excerpt from spacedaily.comAccording to the new method, Saturn's day is 10 hours, 32 minutes and 44 seconds long. Tracking the rotation speed of solid planets, like the Earth and Mars, is a relatively simple task: Just measure the time it tak...

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Young Jupiter wiped out solar system’s early inner planets, study says


Ganymede
(Photo : NASA/ESA) In early days of solar system, Jupiter destroyed everything that came in its way, researchers have found.


Excerpt from latimes.com

Before Mercury, Venus, Earth and Mars occupied the inner solar system, there may have been a previous generation of planets that were bigger and more numerous – but were ultimately doomed by Jupiter, according to a new study.

If indeed the early solar system was crowded with so-called super-Earths, it would have looked a lot more like the planetary systems found elsewhere in the galaxy, scientists wrote Monday in the Proceedings of the National Academy of Sciences.


Inner planets
As NASA’s Kepler space telescope has found more than 1,000 planets in orbit around other stars, along with more than 4,000 other objects that are believed to be planets but haven’t yet been confirmed. Kepler finds these planets by watching their host stars and registering tiny drops in their brightness – a sign that they are being ever-so-slightly darkened by a planet crossing in front of them.

In addition, ground-based telescopes have detected hundreds of exoplanets by measuring the wiggles of distant stars. Those stars wiggle thanks to the gravitational pull of orbiting planets, and the Doppler effect makes it possible to estimate the size of these planets.

The more planetary systems astronomers discovered, the more our own solar system looked like an oddball. Exoplanets – at least the ones big enough for us to see – tended to be bigger than Earth, with tight orbits that took them much closer to their host stars. In multi-planet systems, these orbits tended to be much closer together than they are in our solar system. For instance, the star known as Kepler-11 has six planets closer to it than Venus is to the sun.

Why does our solar system look so different? Astrophysicists Konstantin Batygin of Caltech and Greg Laughlin of UC Santa Cruz summed it up in one word: Jupiter.

Here’s what could have happened, according to their models:

In Solar System 1.0, the region closest to the sun was occupied by numerous planets with masses several times bigger than that of Earth. There were also planetesimals, “planetary building blocks” that formed within the first million years after the birth of the sun, Batygin and Laughlin wrote.

This is how things might have stayed if the young Jupiter had stayed put at its initial orbit, between 3 and 10 astronomical units away from the sun. (An astronomical unit, or AU, is the distance between the Earth and the sun. Today, Jupiter’s orbit ranges between 5 and 5.5 AUs from the sun.)

But Jupiter was restless, according to a scenario known as the “Grand Tack.” In this version of events, Jupiter was swept up by the currents of gas that surrounded the young sun and drifted toward the center of the solar system.

Jupiter, however, was too big to travel solo. All manner of smaller objects would have been dragged along too. With so many bodies in motion, there would have been a lot of crashes.

The result was “a collisional cascade that grinds down the planetesimal population to smaller sizes,” the astrophysicists wrote. For the most part, these planetary crumbs were swept toward the sun and ultimately destroyed, like disintegrating satellites falling back to Earth.

The planetesimals wouldn’t have been Jupiter’s only victims. Assuming the early solar system resembled the planetary systems spied by Kepler and other telescopes, there would have been “a similar population of first-generation planets,” the pair wrote. “If such planets formed, however, they were destroyed.”

Jupiter probably got about as close to the sun as Mars is today before reversing course, pulled away by the gravity of the newly formed Saturn. That would have ended the chaos in the inner solar system, allowing Earth and the other rocky planets to form from the debris that remained.

“This scenario provides a natural explanation for why the inner Solar System bears scant resemblance to the ubiquitous multi-planet systems” discovered by Kepler and other survey efforts, Batygin and Laughlin wrote.

Although their models show that this is what might have happened, they don’t prove that it actually did. But there may be a way to get closer to the truth.

The scientists’ equations suggest that if a star is orbited by a cluster of close-in planets, there won’t be a larger, farther-out planet in the same system. As astronomers find more exoplanetary systems, they can see whether this prediction holds up.

Also, if far-away solar systems are experiencing a similar series of events, telescopes ought to be able to detect the extra heat thrown off by all of the planetesimal collisions, they added.

Sadly for those hoping to find life on other planets, the pair’s calculations also imply that most Earth-sized planets are lacking in water and other essential compounds that can exist in liquid or solid form. As a result, they would be “uninhabitable,” they wrote.

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Scientists: Enceladus may have warm water ocean with ingredients for life


Enceladus ocean
This artist's impression of the interior of Saturn's moon Enceladus shows that interactions between hot water and rock occur at the floor of the subsurface ocean -- the type of environment that might be friendly to life, scientists say. (NASA/JPL-Caltech)



Excerpt from latimes.com

Scientists say they’ve discovered evidence of a watery ocean with warm spots hiding beneath the surface of Saturn’s icy moon Enceladus. The findings, described in the journal Nature, are the first signs of hydrothermal activity on another world outside of Earth – and raise the chances that Enceladus has the potential to host microbial life.

Scientists have wondered about what lies within Enceladus at least since NASA’s Cassini spacecraft caught the moon spewing salty water vapor out from cracks in its frozen surface. Last year, a study of its gravitational field hinted at a 10-kilometer-thick regional ocean around the south pole lying under an ice crust some 30 to 40 kilometers deep.

Another hint also emerged about a decade ago, when Cassini discovered tiny dust particles escaping Saturn’s system that were nanometer-sized and rich in silicon.

“It’s a peculiar thing to find particles enriched with silicon,” said lead author Hsiang-Wen Hsu, a planetary scientist at the University of Colorado, Boulder. In Saturn’s moons and among its rings, water ice dominates, so these odd particles clearly stood out.

The scientists traced these particles’ origin to Saturn’s E-ring, which lies between the orbits of the moons Mimas and Titan and whose icy particles are known to come from Enceladus. So Hsu and colleagues studied the grains to understand what was going on inside the gas giant’s frigid satellite.   
Rather than coming in a range of sizes, these particles were all uniformly tiny – just a few nanometers across. Studying the spectra of these grains, the scientists found that they were made of silicon dioxide, or silica. That’s not common in space, but it’s easily found on Earth because it’s a product of water interacting with rock. 

Knowing how silica interacts in given conditions such as temperature, salinity and alkalinity, the scientists could work backward to determine what kind of environment creates these unusual particles.

A scientist could do the same thing with a cup of warm coffee, Hsu said.

“You put in the sugar and as the coffee gets cold, if you know the relation of the solubility of sugar as a function of temperature, you will know how hot your coffee was,” Hsu said. “And applying this to Enceladus’s ocean, we can derive a minimum [temperature] required to form these particles.”

The scientists then ran experiments in the lab to determine how such silica particles came to be. With the particles’ particular makeup and size distribution, they could only have formed under very specific circumstances, the study authors found, determining that the silica particles must have formed in water that had less than 4% salinity and that was slightly alkaline (with a pH of about 8.5 to 10.5) and at temperatures of at least 90 degrees Celsius (roughly 190 degrees Fahrenheit).

The heat was likely being generated in part by tidal forces as Saturn’s gravity kneads its icy moon. (The tidal forces are also probably what open the cracks in its surface that vent the water vapor into space.)
Somewhere inside the icy body, there was hydrothermal activity – salty warm water interacting with rocks. It’s the kind of environment that, on Earth, is very friendly to life.  

“It’s kind of obvious, the connection between hydrothermal interactions and finding life,” Hsu said. “These hydrothermal activities will provide the basic activities to sustain life: the water, the energy source and of course the nutrients that water can leach from the rocks.”

Enceladus, Hsu said, is now likely the “second-top object for astrobiology interest” – the first being Jupiter’s icy moon and fellow water-world, Europa.
This activity is in all likelihood going on right now, Hsu said – over time, these tiny grains should glom together into larger and larger particles, and because they haven’t yet, they must have been recently expelled from Enceladus, within the last few months or few years at most.

Gabriel Tobie of the University of Nantes in France, who was not involved in the research, compared the conditions that created these silica particles to a hydrothermal field in the Atlantic Ocean known as Lost City.

“Because it is relatively cold, Lost City has been posited as a potential analogue of hydrothermal systems in active icy moons. The current findings confirm this,” Tobie wrote in a commentary on the paper. “What is more, alkaline hydrothermal vents might have been the birthplace of the first living organisms on the early Earth, and so the discovery of similar environments on Enceladus opens fresh perspectives on the search for life elsewhere in the Solar System.”

However, Hsu pointed out, it’s not enough to have the right conditions for life – they have to have been around for long enough that life would have a fighting chance to emerge.

“The other factor that is also very important is the time.… For Enceladus, we don’t know how long this activity has been or how stable it is,” Hsu said. “And so that’s a big uncertainty here.”

One way to get at this question? Send another mission to Enceladus, Tobie said.

“Cassini will fly through the moon’s plume again later this year,” he wrote, “but only future missions that can undertake improved in situ investigations, and possibly even return samples to Earth, will be able to confirm Enceladus’ astrobiological potential and fully reveal the secrets of its hot springs. ”

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Confirmed: Jupiter’s moon Ganymede has a salt water ocean

GanymedeExcerpt from latimes.comAstronomers have found the most conclusive evidence yet that a large watery ocean lies beneath the surface of Jupiter's moon Ganymede.Scientists have suspected for decades that a subterranean ocean ...

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Dawn Enters Orbit Around Dwarf Planet Ceres ~ Video

Ceres Dawn




Dwarf Planet Ceres

Excerpt from spacenews.com

NASA’s Dawn spacecraft arrived in orbit around the dwarf planet Ceres March 6, completing a journey of nearly seven and a half years and five billion kilometers.  In a statement, NASA’s Jet Propulsion Laboratory said Dawn entered orbit about 61,000 kilometers above Ceres at 7:39 am EST March 6, sending a signal to Earth about an hour later confirming it was in orbit and in good health.  “We feel exhilarated,” Dawn principal investigator Chris Russell said in the statement. “We have much to do over the next year and a half, but we are now on station with ample reserves, and a robust plan to obtain our science objectives.”

Dawn will gradually spiral down to its initial science orbit, 13,500 kilometers above Ceres, by April. Later in its mission Dawn will move gradually closer to the surface, eventually moving into an orbit of 375 kilometers.  The Dawn spacecraft, built by Orbital ATK, launched on a United Launch Alliance Delta 2 rocket in September 2007. After making a gravity assist flyby of Mars in February 2009, it entered orbit around the large main-belt asteroid Vesta in July 2011. It remained there for more than a year, using its ion thrusters to leave orbit in September 2012 to head to Ceres. 

Ceres, the largest object in the main asteroid belt between the orbits of Mars and Jupiter, was the first asteroid discovered by astronomers, in 1801. The International Astronomical Union designated Ceres a “dwarf planet” in 2006, a new category of objects that also includes the former planet Pluto.


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Dawn will gradually spiral down to its initial science orbit, 13,500 kilometers above Ceres, by April. Later in its mission Dawn will move gradually closer to the surface, eventually moving into an orbit of 375 kilometers.
The Dawn spacecraft, built by Orbital ATK, launched on a United Launch Alliance Delta 2 rocket in September 2007. After making a gravity assist flyby of Mars in February 2009, it entered orbit around the large main-belt asteroid Vesta in July 2011. It remained there for more than a year, using its ion thrusters to leave orbit in September 2012 to head to Ceres.
Ceres, the largest object in the main asteroid belt between the orbits of Mars and Jupiter, was the first asteroid discovered by astronomers, in 1801. The International Astronomical Union designated Ceres a “dwarf planet” in 2006, a new category of objects that also includes the former planet Pluto.
- See more at: http://spacenews.com/dawn-enters-orbit-around-ceres/#sthash.yoclEQI4.dpuf
WASINGTON — NASA’s Dawn spacecraft arrived in orbit around the dwarf planet Ceres March 6, completing a journey of nearly seven and a half years and five billion kilometers.
In a statement, NASA’s Jet Propulsion Laboratory said Dawn entered orbit about 61,000 kilometers above Ceres at 7:39 am EST March 6, sending a signal to Earth about an hour later confirming it was in orbit and in good health.
“We feel exhilarated,” Dawn principal investigator Chris Russell said in the statement. “We have much to do over the next year and a half, but we are now on station with ample reserves, and a robust plan to obtain our science objectives.”
- See more at: http://spacenews.com/dawn-enters-orbit-around-ceres/#sthash.yoclEQI4.dpuf

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Exoplanet Bonanza Boosts Count by 1,200

Excerpt from news.discovery.comDozens of candidate worlds reside within the "habitable zones" of their parent stars. THE GIST - NASA's Kepler telescope has found more than 1,200 extrasolar planet candidates. - Smaller worlds, like Earth,...

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Chances of Exoplanet Life ‘Impossible’? Or ‘100 percent’?


Kepler’s Exoplanets: A map of the locations of exoplanets, of various masses, in the Kepler field of view. 1,235 candidates are plotted (NASA/Wendy Stenzel)


 news.discovery.com 

Just in case you haven’t heard, our galaxy appears to be teeming with small worlds, many of which are Earth-sized candidate exoplanets and dozens appear to be orbiting their parent stars in their “habitable zones.”

Before Wednesday’s Kepler announcement, we knew of just over 500 exoplanets orbiting stars in the Milky Way. Now the space telescope has added another 1,235 candidates to the tally — what a difference 24 hours makes.

Although this is very exciting, the key thing to remember is that we are talking about exoplanet candidates, which means Kepler has detected 1,235 exoplanet signals, but more work needs to be done (i.e. more observing time) to refine their orbits, masses and, critically, to find out whether they actually exist.

But, statistically speaking, a pattern is forming. Kepler has opened our eyes to the fact our galaxy is brimming with small worlds — some candidates approaching Mars-sized dimensions!

Earth-Brand™ Life

Before Kepler, plenty of Jupiter-sized worlds could be seen, but with its precision eye for spotting the tiniest of fluctuations of star brightness (as a small exoplanet passes between Kepler and the star), the space telescope has found that smaller exoplanets outnumber the larger gas giants.

Needless to say, all this talk of “Earth-sized” worlds (and the much-hyped “Earth-like” misnomer) has added fuel to the extraterrestrial life question: If there’s a preponderance of small exoplanets — some of which orbit within the “sweet-spot” of the habitable zones of their parent stars — could life as we know it (or Earth-Brand™ Life as I like to call it) also be thriving there?
Before I answer that question, let’s turn back the clock to Sept. 29, 2010, when, in the wake of the discovery of the exoplanet Gliese 581 g, Steven Vogt, professor of astronomy and astrophysics at University of California Santa Cruz, told Discovery News: “Personally, given the ubiquity and propensity of life to flourish wherever it can, I would say that the chances for life on [Gliese 581 g] are 100 percent. I have almost no doubt about it.”

Impossible? Or 100 Percent?

As it turns out, Gliese 581 g may not actually exist — an excellent example of the progress of science scrutinizing a candidate exoplanet in complex data sets as my Discovery News colleague Nicole Gugliucci discusses in “Gliese 581g and the Nature of Science” — but why was Vogt so certain that there was life on Gliese 581 g? Was he “wrong” to air this opinion?

Going to the opposite end of the spectrum, Howard Smith, an astrophysicist at Harvard University, made the headlines earlier this year when he announced, rather pessimistically, that aliens will unlikely exist on the extrasolar planets we are currently detecting.
“We have found that most other planets and solar systems are wildly different from our own. They are very hostile to life as we know it,” Smith told the UK’s Telegraph.

Smith made comparisons between our own solar system with the interesting HD 10180 system, located 127 light-years away. HD 10180 was famous for a short time as being the biggest star system beyond our own, containing five exoplanets (it has since been trumped by Kepler-11, a star system containing six exoplanets as showcased in Wednesday’s Kepler announcement).

One of HD 10180′s worlds is thought to be around 1.4 Earth-masses, making it the smallest detected exoplanet before yesterday. Alas, as Smith notes, that is where the similarities end; the “Earth-sized” world orbiting HD 10180 is too close to its star, meaning it is a roasted exoplanet where any atmosphere is blasted into space by the star’s powerful radiation and stellar winds.
The Harvard scientist even dismissed the future Kepler announcement, pointing out that upcoming reports of habitable exoplanets would be few and far between. “Extrasolar systems are far more diverse than we expected, and that means very few are likely to support life,” he said.

Both Right and Wrong

So what can we learn about the disparity between Vogt and Smith’s opinions about the potential for life on exoplanets, regardless of how “Earth-like” they may seem?

Critically, both points of view concern Earth-Brand™ Life (i.e. us and the life we know and understand). As we have no experience of any other kind of life (although the recent eruption of interest over arsenic-based life is hotly debated), it is only Earth-like life we can realistically discuss.

We could do a Stephen Hawking and say that all kinds of life is possible anywhere in the cosmos, but this is pure speculation. Science only has life on Earth to work with, so (practically speaking) it’s pointless to say a strange kind of alien lifeform could live on an exoplanet where the surface is molten rock and constantly bathed in extreme stellar radiation.

If we take Hawking’s word for it, Vogt was completely justified for being so certain about life existing on Gliese 581 g. What’s more, there’s no way we could prove he’s wrong!

But if you set the very tight limits on where we could find Earth-like life, we are suddenly left with very few exoplanet candidates that fit the bill. Also, just because an Earth-sized planet might be found in the habitable zone of its star, doesn’t mean it’s actually habitable. There are many more factors to consider. So, in this case, Smith’s pessimism is well placed.

Regardless, exoplanet science is in its infancy and the uncertainty with the “is there life?” question is a symptom of being on the “raggedy edge of science,” as Nicole would say. We simply do not know what it takes to make a world habitable for any kind of life (apart from Earth), but it is all too tempting to speculate as to whether a race of extraterrestrials, living on one of Kepler’s worlds, is pondering these same questions.

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Is This a Baby Picture of a Giant Planet?


Hubble optical image (left) and VLT infrared image (right) of the circumstellar disk surrounding HD 100546. (ESO/NASA/ESA/Ardila et al.)


Excerpt from news.discovery.com


Mommy, where do baby planets come from? There’s no storks, birds, bees, or romantic dinners for two involved in the answer to that question — regardless of size, planets are all formed in pretty much the same way: through the aggregation of material within the disk of dust and gas surrounding a young star. While how long it actually takes and just what sort of planets are most likely to form where are still topics of discussion among astronomers, the birth process of a planet is fairly well understood.

And this may be the very first image of it actually happening.

Acquired by the European Southern Observatory’s Very Large Telescope (VLT), the infrared image above (right) shows a portion of the disk of gas and dust around the star HD100546, located 335 light-years away in the constellation Musca. By physically blocking out the light from the star itself by means of an opaque screen — seen along the left side of the image — the light from the protoplanetary disk around HD 100546 can be seen, revealing a large bright clump that’s thought to be a planet in the process of formation.

If it is indeed a baby planet, it’s a big one — as large as, or perhaps even larger than, Jupiter.

A candidate protoplanet found in a disc of gas and dust around young star HD100546 (ESO)


This does raise an interesting question for astronomers because if it is a Jupiter-sized planet, it’s awfully far from its star… at least according to many current models of planetary formation. About 68 times as far from HD100546 as we are from the sun, if this planet were in our solar system it’d be located deep in the Kuiper Belt, twice as far as Pluto. That’s not where one would typically expect to find gas giants, so it’s been hypothesized that this protoplanet might have migrated outwards after initially forming closer to the star… perhaps “kicked out” by gravitational interaction with an even more massive planet.

Alternatively, it may not be a planet at all — the bright blob in the VLT image might be coming from a much more distant source. While extremely unlikely, further research will be needed to rule that possibility out.

If it’s found to be a planet, HD100546 “b” would offer scientists an unprecedented opportunity to observe a planetary formation process in action — and from a relatively close proximity as well.

According to the team’s paper, submitted to Astrophysical Journal Letters, ”What makes HD100546 particularly interesting is that 1. it would be the first imaged protoplanet that is still embedded in the gas and dust disk of its host star; and 2. it would show that planet formation does occur at large orbital separations.”

(Now all we have to do is wait a couple billion years and then show these pictures to HD100546b’s girlfriend. How embarrassing!)

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Astronomers Find Massive Exoplanet With Four Parent Stars

Artist rendering of the system 30 Ari with its exoplanet and four stars. Excerpt from techtimes.com By Dianne Depra  Researchers seeking to study the complexities of exoplanets with multiple stars have found a new system with four. Cal...

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Beautiful Sight Expected In The Skies Tonight



The moon and planet Jupiter will be able to be seen with your naked eyes. And, with some basic binoculars, you’ll be able to see even more. (Photo: UW Space Place)
The moon and planet Jupiter will be able to be seen with your naked eyes. And, with some basic binoculars, you’ll be able to see even more. (Photo: UW Space Place)



Excerpt from wric.com

Just look up! Monday night, you’ll be able to see a beautiful sight. Jupiter and the moon will be the brightest objects in the sky. And, with some basic binoculars, you’ll be able to see even more.

The largest planet in our solar system, Jupiter, will be pairing up with the moon Monday night. The moon makes a pass by Jupiter, and every planet, at some point each month during its orbit. Monday night, the moon will appear fairly large, called a waxing gibbous moon, and that only happens every few years, according to Jim Lattis, Director of UW Space Place at the University of Wisconsin-Madison.

“But the interest need not be in whether it’s unusual.  Rather, it’s a beautiful sight and leads people to look up and think about astronomical things and our place among them,” Lattis said.

After Venus sets, Jupiter and the moon will be the two brightest objects in the sky. Jupiter and the moon will reach the high point in our skies in late evening. With binoculars or a telescope, you’ll even be able to see some of Jupiter’s Galilean moons. They’ll look like little points of light.

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Skywatch: Venus and Jupiter continue to accentuate the night heavens


Venus (right) & Jupiter


Excerpt from washingtonpost.com
By Blaine Friedlander Jr. 
In winter’s waning weeks, Venus and Jupiter continue to accentuate the night heavens, we change our clocks forward and we grab spring with no intention of letting go.

Check the west-southwestern heavens at dusk to spy the vivacious Venus and the dim Mars. In late February, the two planets met for a sweet cosmic waltz, but in March, they appear to separate. Venus approaches negative fourth magnitude (very bright) while Mars makes do at magnitude 1.3 (dim, hard to find in urban light pollution). With a clear sky, Mars looks like a red pinpoint. 

A young, waxing crescent moon visits Mars on the evening of March 21, and on the next evening the crescent flirts with Venus.
Robust Jupiter ascends the evening’s eastern sky. Find this gas giant at a -2.5 magnitude, very bright, in the constellation Cancer. The lion in the constellation Leo appears to stare at the planet. By the Ides of March, find it south around 10:30 p.m. 

The waxing gibbous moon drops by the dazzling Jupiter on March 2, days before the moon itself becomes full on March 5. 

Catch the ringed Saturn rising after midnight in the east-southeast now, hanging out near a gang of constellations, Scorpius, Ophiuchus and Libra. It’s a zero magnitude object, bright enough that it can be seen under urban skies. The waning moon loiters near Saturn before dawn on March 12. On that morning, the reddish star below them is Antares.
We adjust our clocks to Daylight Saving Time at 2 a.m. March 8. Spring forward, moving the clock ahead one hour. 

Winter is almost over. Spring is weeks away. The vernal equinox brings spring’s official arrival on March 20 at 6:45 p.m. 

Also on March 20 — the day a new moon — the North Atlantic and the Arctic waters get a short total eclipse. We won’t see it here, but Slooh.com will carry it live. Totality will start seconds after 5:44 a.m. and end at 5:47 a.m., according to Geoff Chester of the U.S. Naval Observatory. 

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As Dawn Spacecraft Approaches, A Second Mysterious Light Emerges on Planet Ceres

Photo : NASA/JPL-Caltech/UCLA/MPS/DLR/IDA/PSI Excerpt from sciencetimes.com Originally discovered in 1801 by an astronomer in Sicily, Ceres has had quite an interesting history to date. Originally believed to be a shining star in the sky, when i...

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