The comet, which moves in an elliptical orbit around the Sun, will at rendezvous be some 675 million kilometres from the Sun, near the point in its orbit farthest from the Sun. The meeting point was not chosen at random: at this point the comet is still barely active, it is still in fact a frozen lump of ice and interplanetary dust, in all probability the matter from which our solar system emerged four and a half billion years ago. Rosetta's job is to find out more about these strange bodies that travel through our solar system. As it moves on, the comet will begin to change. As it approaches the Sun, it will - like all comets - become active: in the warmth of the Sun's rays, the ices evaporate, tearing small dust particles from the surface. This produces the comet head (the coma) and tail during solar flyby skims several metres of matter off the comet's surface. In the case of a small comet like Churyumov-Gerasimenko, the shrinkage is a good 1% each time round." As it flies past the Sun every 6.6 years it can look forward to a short future, especially on a cosmic timescale.

At 1 am Israel time (UTC+2) on the 28th of January 2011, two videos were recorded in central Jerusalem. Both videos appear to have filmed the same event from different positions: A white ball of light descends from the sky and hovers over and slightly to the East of the Dome of the Rock, approximately over the garden of Gethsemane. After about 30 seconds, the ball of light shoots off into the sky at high speed.

First video shot from about 4 kms to the South of the Dome:


Second video, shot from what appears be just a few hundred meters to the West of the Dome:


Strangely enough at exactly the same time (all three were filmed at 11pm UTC on the 27th Jan.), another interesting aerial phenomena was being recorded at least 1000kms to the North East in Kazakhstan...

Astronomy books and papers far too numerous to cite offer the assurance that "no one has ever been killed by a meteorite." (John S. Lewis, University of Arizona)

©Julian Baum

Over the past few years, while sott.net has been tracking the increasing flux of fireballs and meteorites entering the earth's atmosphere, we have been, by turns, amused and horrified at the ignorant reactions and declarations that issue from academia and the media regarding these incursions. A few years ago, we read that "this is a 'once in a hundred years' event!" Not long after it was a "once in a lifetime" event. Still later, after a lot more incidents it became a "once in a decade" event. More recently, it has been admitted in some quarters that meteorites hit the ground (as opposed to safely burning up in the atmosphere) several times a year! And of course, we have discovered the fact that the governments of our planet are well aware that there are atmospheric explosions from such bodies numerous times a year. We have also learned in this series that the frequent reports of unusual booms and shaking of the ground is often due to such overhead explosions. Yet the media steadfastly refuses to honestly address this issue, though we have noted a plethora of recent articles presenting opposing academic arguments designed to put the populace back to sleep, to reassure them that there is nothing to worry about, that such things only happen every 100,000 years or so, and certainly, the Space Watch Program is going to find all the possible impactors and take care of things.

The mysterious, spectacular flare of Comet 17P/Holmes has been observed three times, and it may give warning of an imminent explosion fueled by carbon monoxide gas when it returns in 2014, say astronomers.

Holmes shocked the world in October 2007 when it suddenly brightened by a factor of 500,000, going from a humdrum ball of dust to a brilliant orb visible to the naked eye. The comet spewed 100 million tons of dust into space, comparable to the amount of ash unleashed by Mount St. Helens, and briefly swelled to a diameter greater than the sun's.

But despite months of observations from hundreds of telescopes, the cause of Holmes' dramatic explosion remains unknown.

Astronomers initially suggested that a dusty crust may have formed on the comet's nucleus as it approached the sun, trapping frozen ice underneath. As it neared the sun, the surface would heat so rapidly that the ice turned from solid to gas without even melting. Gas would build up and burst through the crust, sending Holmes' innards flying outward.

Comet Hartley 2 has graced our night skies for several weeks, reaching its closest approach (unfortunately timed near the full moon) on October 18th. NASA is taking advantage of this near approach to visit the comet with the Deep Impact/EPOXI mission, and they are already making surprising discoveries.

Deep Impact put on a spectacular show for scientists and space-geeks alike when it rendezvoused with Comet Tempel 1 in 2005, smashing a projectile into the dirty snowball in order to see what lies just beneath the surface. The mission, now renamed EPOXI, has taken the spacecraft past Earth several times on its way to a new cometary target, Hartley 2.

The craft's closest approach to the comet will be on November 4th, when it will pass just 435 miles from the comet nucleus just as it is starting to warm up and become active in its approach of the Sun. However, science observations are already underway, as data taken in early September indicates that Hartley 2 increased its cyanide output five-fold over a period of just eight days.

NASA's Deep Impact mission pounded a comet in 2005, but failed to see the resulting crater. Now, scientists will get a second chance to glimpse the damage when a second spacecraft flies by the comet on 15 February.

In an unprecedented experiment, NASA smashed a 372-kilogram impactor into Comet Tempel 1 on 4 July 2005 as part of its Deep Impact mission.

A flyby spacecraft recorded images of the impact from a safe distance, but the cloud of impact debris and a flawed camera made it impossible to see the crater itself. Studying the crater could have revealed more about the interior composition and structure of comets.

Now, another spacecraft is about to make its own fly-by of the comet, offering a second chance to image the structure.

Called Stardust, the spacecraft collected material from Comet Wild 2 in 2004 and sent it in a capsule back to Earth, where scientists have been studying it ever since.

One of the members of our research team is an astronomer at a large observatory. We've been having a number of exchanges about the theories of James McCanney. Unfortunately, I can't find any really good videos of McCanney talking about his ideas. I did find the following which are basically just audio with minimal graphics. They do explain his ideas so have a listen before you continue on. If anybody has links to better videos, please let me know!

A comet may have hit the planet Neptune about two centuries ago. This is indicated by the distribution of carbon monoxide in the atmosphere of the gas giant that researchers -- among them scientists from the French obser-vatory LESIA in Paris, from the Max Planck Institute for Solar System Re-search (MPS) in Katlenburg-Lindau (Germany) and from the Max Planck Insti-tute for Extraterrestrial Physics in Garching (Germany) -- have now studied. The scientists analyzed data taken by the research satellite Herschel, that has been orbiting the Sun in a distance of approximately 1.5 million kilometers since May 2009. The research is published in Astronomy & Astrophysics (July 16, 2010).

When the comet Shoemaker-Levy 9 hit Jupiter sixteen years ago, scientists all over the world were prepared: instruments on board the space probes Voyager 2, Galileo and Ulysses documented every detail of this rare incident. Today, this data helps scientists detect cometary impacts that happened many, many years ago. The "dusty snowballs" leave traces in the atmosphere of the gas giants: water, carbon dioxide, carbon monoxide, hydrocyanic acid, and carbon sulfide. These molecules can be detected in the radiation the planet radiates into space.

In February 2010 scientists from Max Planck Institute for Solar System Research discovered strong evidence for a cometary impact on Saturn about 230 years ago (see Astronomy and Astrophysics, Volume 510, February 2010). Now new measurements performed by the instrument PACS (Photodetector Array Camera and Spectrometer) on board the Herschel space observatory indicate that Neptune experienced a similar event. For the first time, PACS allows researchers to analyze the long-wave infrared radiation of Neptune.

Researchers at the University of Tennessee have suggested that lunar water may have originated from comets smashing into the moon soon after it formed.

Larry Taylor, a distinguished professor in the Department of Earth and Planetary Sciences, was the one last year to discover trace amounts of water on the moon.

This discovery debunked beliefs held since the return of the first Apollo rocks that the moon was bone-dry.

Taylor and his fellow researchers conducted their study by analyzing rocks brought back from the Apollo mission.

Using secondary ion mass spectrometry, the researchers measured the samples' 'water signatures', which tell the possible origin of the water-and made the surprising discovery that the water on the Earth and moon are different.

"This discovery forces us to go back to square one on the whole formation of the Earth and moon. Before our research, we thought the Earth and moon had the same volatiles after the Giant Impact, just at greatly different quantities. Our work brings to light another component in the formation that we had not anticipated-comets," said Taylor.