. . . and from heaven a great star shall fall on the dread ocean and burn up the deep sea, with Babylon itself and the land of Italy, by reason of which many of the Hebrews perished,

. . . Be afraid, ye Indians and high-hearted Ethiopians: for when the fiery wheel of the ecliptic(?) . . . and Capricorn . . . and Taurus among the Twins encircles the mid-heaven, when the Virgin ascending and the Sun fastening the girdle round his forehead dominates the whole firmament; there shall be a great conflagration from the sky, falling on the earth;

Are these lines from Book V of the Sibylline Oracles eschatological nonsense? Contemporary astronomical evidence suggests a historic basis for words describing cosmic calamity. British astronomers, Victor Clube and Bill Napier, in The Cosmic Winter (1990) and other recent works, provide students of the past with newly discovered celestial clues which indicate that Earth has been periodically pelleted with comet fragments throughout the Holocene period. The evidence for the break-up of a large (> 50 km), short period (approximately 3.3 years), Earth-orbit-crossing comet is substantial and should be considered as hard as anything a trowel might turn up. What astronomical information cannot convey is the actual effect these periodic bombardment episodes had on human culture; only further digging and sifting will illuminate that aspect.

Scientists from Boston University's Center for Space Physics reported today that NASA satellites designed to view the escaping atmosphere of the Sun have also recorded evidence of escaping gas from the planet Mercury. The STEREO mission has two satellites placed in the same orbit around the Sun that the Earth has, but at locations ahead and behind it. This configuration offers multi-directional views of the electrons and ions that make up the escaping solar wind. On occasion, the planet Mercury appears in the field of view of one or both satellites.

In addition to its appearance as a bright disk of reflected sunlight, a "tail" of emission can be seen in some of the images. Announcing this new method of observing Mercury and trying to understand the nature of the gases that might make up this tail feature were the topics presented at the European Planetary Science Congress meeting in Rome today.

It has been known that Mercury exhibits comet-like features, with a coma of tenuous gas surrounding the planet and a very long tail extending in the anti-sunward direction. From Earth, observations of both of these features can be done using light from sodium gas sputtered off the surface of Mercury. The Sun's radiation pressure then pushes many of the sodium atoms in the anti-solar direction creating a tail that extends many hundreds of times the physical size of Mercury.

Comets, sometimes called "dirty snowballs," are largely composed of water. An international research team led by Andreas Wolf of the Max-Planck Institute for Nuclear Physics in Heidelberg, Germany, recently succeeded in deciphering an important aspect of the way in which water molecules often form in space. As a surprise, the water molecules produced under cold, dilute conditions turned out to be produced as particles as hot as 60,000 Kelvin. In their research the physicists, though, did not use a telescope, but a particle accelerator.

The research appears in the journal Physical Review Letters.

In comets as well as in interstellar clouds, the precursor molecule of water is the positively charged hydronium ion H3O+. This molecular ion can be detected from earth by telescopes. In the cosmic clouds negatively charged electrons are also present, causing frequent collisions. In those the hydronium ion converts to the neutral instable radical H3O, which rapidly decays. "For this break-up reaction, nature offers three choices," describes Andreas Wolf, forming either H2O plus H, or OH plus H2, or OH plus two H atoms. Present research tries to determine the yields of these production channels, including that of water.

Researchers have modeled the likely path taken by Halley's comet in the 5th century BC and compared their findings to ancient Greek texts from the period. They now suggest the ancient Greeks saw the comet, which would make the sightings over two centuries earlier than previous known observations.

Chinese astronomers first described the comet in 240 BC, but in ancient Greece in 466-467 BC Greek authors described a meteor the size of a wagon that crashed into the Hellespont region of northern Greece during daylight hours, frightening the population and creating a tourist attraction that lasted five centuries. The ancient authors describe a comet in the sky at the time.

Researchers Daniel Graham, a philosopher, and Eric Hintz, an astronomer, from Brigham Young University at Provo in Utah, compared their model of the comet's likely path with the texts describing the meteor crash. Halley's comet would have been visible for 82 days maximum, depending on atmospheric conditions at the time, while the ancient texts say the comet was visible for 75 days.

The shock waves caused as comets hit the early Earth could have helped promote the formation of amino acids and the early building blocks of life, say US researchers.

It is thought that amino acids and short peptides played a significant role in the chemical evolution that resulted in life on Earth, but researchers have historically disagreed on how these chemicals got here in the first place.

Researchers at the Lawrence Livermore National Laboratory and Stanford University have now run theoretical simulations of shock compressions that mimic the conditions created when a comet hits the Earth, which suggest that the ingredients for life on Earth could have been delivered from space.

Comets are made of dust, ice and compressed gases. The ice is predominantly water, but is also known to contain small molecules that promote bacterial growth - prebiotic molecules - such as carbon dioxide, ammonia and methanol.

Material from the Trojan asteroids that exist around the orbit of Neptune could go on to become comets that could strike our planet, according to a new study.

Many comets swing into the inner solar system every 200 to 300 years.

The origin of such so-called "short-period comets" is unknown but the immediate source is thought to be the Centaurs-these are a collection of an estimated million icy objects more than 1 kilometre across on elliptical orbits that come closest to the sun between the orbits of Jupiter and Neptune.

Only about 250 of these Centaurs have been imaged by telescopes. All are on unstable orbits, and have a big chance of receiving a gravitational boost when their orbit brings them near Jupiter or one of the other giant planets. Such perturbation could redirect them into the inner solar system - and possibly towards Earth.

As a wayward Centaur approaches the sun, its heat begins to evaporate the icy contents, resulting in a cometary tail.

In my day work I am no stranger to government bureaucracies and "programs" manipulating information about their activities until it suits them to do otherwise. The WISE mission is no different.

In March of this year David Shiga wrote an obviously informed article revealing early results of the WISE mission (below). Six weeks into WISE's work, someone revealed to Shiga (I don't think it is press release material, but prove me wrong) that 16 NEO's had been identified, and strangely, these objects were in comet-like inclined orbits (making them comets). Then, this week, six month later, we get an update from the JPL mission team reporting a total of 15 new "comets" have been found, and 25,000 new "asteroids."

What happened to the original 16 objects with inclined orbits? Are they now just lumped in with asteroids? How many of the "asteroids" orbits are inclined (making them comets)?.

The WISE mission is massaging, or least showing no consistency, in their use of the terms comet and asteroid in their press releases or private communication with the media. I am sure the public will able to sort this out in six more months as promised in the JPL press release. But the opaque and clumsy treatment of this important quasi-public information in the popular press in the meantime is disappointing.

I would love for a reader or two to provide insight and clarification regarding these matters. I do not, for instance, monitor or quite understand the Minor Planet Center. Perhaps all this info is being fed to "Harvard" and WISE feels no responsibility to elaborate in a press releases regarding the finer points of astronomical nomenclature. Or, maybe you sense the same manipulation-without-explanation I do...

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 kilome-ters since May 2009. (Astronomy & Astrophysics, published online on July 16th, 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.

An extrasolar planet nearly as big as Jupiter is circling so close to its parent star -- a year passes in just 3.5 days -- that its atmosphere is being baked off into space, creating a comet-like tail.

The planet, known as HD 209458b, is located about 153 light-years away.

Scientists had suspected since 2003 that stellar winds would be strong enough to sweep the planet's atmosphere into space and had even modeled what it would look like, says Jeffrey Linsky, with the University of Colorado in Boulder, who led a team that used Hubble Space Telescope's Cosmic Origins Spectrograph to make observations.

"We have measured gas coming off the planet at specific speeds, some coming toward Earth. The most likely interpretation is that we have measured the velocity of material in a tail," Linsky said in a press statement.

Earthy speed to get probe 'up close and personal'

A NASA space probe famous for bombing a comet five years ago made a final "flyby" past Earth last night, changing its orbit around the Sun with the aid of the planet's gravity. The renamed "EPOXI" craft (formerly "Deep Impact") swooped low just 19,000 miles above the South Atlantic at 11pm UK time last night.

Last night's 12,750 mph flypast will see the dual-missioned spaceprobe accelerate by no less than 3,470 mph in its bid to reach the comet Hartley 2 later this year. EPOXI's name reflects the two new tasks it was given following the Deep Impact comet-bombing run: Extrasolar Planet Observation and Characterization plus Deep Impact Extended Investigation.

After the successful 2005 strike in which the then Deep Impact smashed a probe into the comet Tempel 1, NASA assessed that the probe still had plenty of manoeuvring fuel left and that, by means of judicious low passes above Earth, it could be steered to a new rendezvous with another comet. The Hartley intercept, however, will not involve an impact probe like the Tempel rendezvous.