The European Space Agency said its Solar and Heliospheric Observatory has sighted -- for the first time -- the third passage of a specific comet.
The space observatory, called SOHO -- a joint ESA project with the National Aeronautics and Space Administration -- has found more than 1,350 comets. But this is the first time it's found a rare type of comet called a periodic comet -- meaning it flies by the sun at regular intervals. While many SOHO-discovered comets are believed to be periodic, this is the first that's been officially declared as such, the ESA said.
Comets
Goddard Space Flight Center - A NASA satellite has captured the first images of a collision between a comet and a solar hurricane. It is the first time scientists have witnessed such an event on another cosmic body. One of NASA's pair of Solar Terrestrial Relations Observatory satellites, known as STEREO, recorded the event April 20.
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| ©NASA |
| This is a still taken from a visualization showing Comet Encke and the coronal mass ejection erupting from the surface of the Sun. |
The Solar and Heliospheric Observatory (SOHO) has spotted an unusual comet that flies around the sun at regular intervals.
Dubbed P/2007 R5 (SOHO), the object belongs to a rare class of comets called periodic comets. Only 190 of the thousands of known comets are periodic. The most famous periodic comet is Halley's Comet, which can be seen from Earth every 76 years and last passed close to the sun in 1986.
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| ©Space.com |
Dubbed P/2007 R5 (SOHO), the object belongs to a rare class of comets called periodic comets. Only 190 of the thousands of known comets are periodic. The most famous periodic comet is Halley's Comet, which can be seen from Earth every 76 years and last passed close to the sun in 1986.
The near-Earth approach of a disintegrating comet in May 2006 gave scientists from the Johns Hopkins University Applied Physics Laboratory a rare opportunity to study its chemical composition.
There is a one-in-10,000 chance that an asteroid or comet, more than two kilometres in diameter, will collide with Earth in the next century, killing a large proportion of the population, according to space scientists.
A GIANT meteor or comet fragment - the size of some of those which last week collided with Jupiter - may have played a key role in determining human history, according to new evidence.
Scientific investigations suggest that a collision between Earth and a celestial body may have been partially responsible for the final demise of classical civilisation and the onset of the Dark Ages.
Scientific investigations suggest that a collision between Earth and a celestial body may have been partially responsible for the final demise of classical civilisation and the onset of the Dark Ages.
Napier et al. assert that life originated in comets, not on planets like Earth. Kennett et al. believe that a large comet impacted North America just 13,000 years ago, causing a mass extinction. For a critique, read on.
Comment: Seems the people at NASA still don't like cometary showers invading the inner solar system. Their "evidence" is the lack of evidence that would explain what their theories predict about comets, dismissing the compelling evidence "on the ground", albeit a lack of a crater, but that could be explained if the comet impacted the Laurentide ice sheet itself, despite their dismissals. It's as if the Inquisition demanded Galileo disprove the bible's contention that there are four corners of Earth before proposing the theory that the earth is, in fact, round. And what about this crater discussed here? And what about the Carolina Bays?
It is generally accepted today that the Tunguska event can only be attributed to a rare encounter with a "comet," or incoming body of such a nature that it left no stony or ferrous material, but simply vaporized and scorched the earth below in a rare display of high energy physics.
To explain the Bays, Kobres proposes a similar encounter, albeit of larger proportions and more accurately described as a "near miss." The "Kobres Event" proposes that a "comet," if you like, whipped past the Earth, exchanging enormous energy but not impacting directly to form a typical crater. It is demonstrable that such an encounter would show an intense flash of heat onto the ground below. This heat would have caused moister portions in the Pleistocene landscape to explode into steam, leaving the depressions in the ground that we know today as "Carolina Bays."
New scientific findings suggest that a large comet may have exploded over North America 12,900 years ago, explaining riddles that scientists have wrestled with for decades, including an abrupt cooling of much of the planet and the extinction of large mammals.
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| ©Allen West, UCSB |
| A "black mat" of algal growth in Arizona marks a line of extinction at 12,900 years ago; Clovis points and mammoth skeletons were found at the line but not above it. |
A rare meteor shower predicted to hit Earth on 1 September should give astronomers only their second chance to study an ancient comet's crust. It could also help them develop a warning system against an otherwise insidious threat - a comet aimed at Earth from the dark fringes of the solar system.
For the first time, there is solid data to refute a popular theory that life came to Earth aboard a comet, Rutgers researchers say.
Deteriorated DNA from microbes, frozen for millions of years in the Antarctic ice, shows that organisms could not have survived the bombardment of cosmic radiation during deep space travel from outside the solar system, said Paul Falkowski, a Rutgers biologist and oceanographer.
Deteriorated DNA from microbes, frozen for millions of years in the Antarctic ice, shows that organisms could not have survived the bombardment of cosmic radiation during deep space travel from outside the solar system, said Paul Falkowski, a Rutgers biologist and oceanographer.
Comment: To find out more about comets and how often they actually collide with our planet, read: Forget About Global Warming: We're One Step From Extinction!