Uncharted Meteors
 by NASA Marshall Space Flight Center and ScienceIQ.com
|
 What does a piece of space dust look like? This picture shows one that is only 10 microns across. It was captured by a U2 aircraft in the stratosphere.
Image Courtesy NASA
|
In 1967, NASA's Mariner 4 spacecraft was cruising through the solar system, not far from Earth, when something unexpected happened. 'Mariner 4 ran into a cloud of space dust,' says Bill Cooke of the Marshall Space Flight Center Space Environments Team. 'For about 45 minutes the spacecraft experienced a shower of meteoroids more intense than any Leonid meteor storm we've ever seen on Earth.' The impacts ripped away bits of insulation and temporarily changed the craft's orientation in space. Fortunately, the damage was slight and the mission's main objective--a flyby of Mars--had been completed two years earlier. But it could have been worse. 'There are many uncharted dust clouds in interplanetary space. Some are probably quite dense,' says Cooke. Most of these clouds are left behind by comets, others are formed when asteroids run into one another. 'We only know about the ones that happen to intersect Earth's orbit and cause meteor showers such as the Perseids or Leonids.' The Mariner 4 cloud was a big surprise.Mapping these clouds and determining their orbits is important to NASA for obvious reasons: the more probes we send to Mars and elsewhere, the more likely they are to encounter uncharted clouds. No one wants their spaceship to be surprised by a meteor shower hundreds of millions of miles from Earth. Much of Cooke's work at NASA involves computer-modeling of cometary debris streams--long rivers of dust shed by comets as they orbit the sun. He studies how clumps form within the streams and how they are deflected by the gravity of planets (especially giant Jupiter). He and his colleagues also watch the sky for meteor outbursts here on Earth. 'It's a good way to test our models and discover new streams,' he says. One such outburst happened on June 27, 1998. Sky watchers were surprised when hundreds of meteors streamed out of the constellation Bootes over a few-hour period. Earth had encountered a dust cloud much as Mariner 4 had done years earlier. The meteors of 1998 were associated with a well-known meteor shower called the June Bootids. Normally the shower is weak, displaying only a few meteors per hour at maximum. But in 1998 it was intense. Similar outbursts had occurred, with no regular pattern, in 1916, 1921, and perhaps 1927. The source of the June Bootids is comet 7P/Pons-Winnecke, which orbits the Sun once every 6.37 years. The comet follows an elliptical path that carries it from a point near the orbit of Earth to just beyond the orbit of Jupiter. Pons-Winnecke last visited the inner solar system in 2002. The comet's dusty trail is evidently clumpy. When our planet passes through a dense spot in the debris stream, a meteor shower erupts.
For more science facts like this one go to: ScienceIQ.com
|
Quick Poll
 |
|
|
|
'Beauty is a harmonious relation between something in our nature and the quality of the object which delights us.'
Blaise Pascal (1623-1662)
|
|
| Xump.com Science Store |
30 Crystals Classroom Kit
Teach your students crystal growing with this complete kit for 30 students.
$69.99 $49.95 /each View details
Glow-in-the-Dark Mega Cosmos
Create a virtual cosmos in your room with over 238 glowing pieces.
$22.99 $16.95 /each View details
Scientists Card Game
Have a fun and educational experience with the game of SCIENTISTS.
$7.99 $5.95 /each View details
Volcano Poster
See the fiery fury of a volcano erupting. Learn all about faults, tremors and why they erupt.
$12.99 $9.95 /each View details
TK Little Labs: Light and Color
Experiment with additive and subtractive colors, mixing colors, visual perception, pigments, the light spectrum, and more.
$19.99 $14.95 /each View details
Click here to view other physics & astronomy related products from our online store.
|
|
| Book Recommendation |
The Universe in a Nutshell by Stephen Hawking
Stephen Hawking, science's first real rock star, may be the least-read bestselling author in history--it's no secret that many people who own A Brief History of Time have never finished it. Hawking's The Universe in a Nutshell aims to remedy the situation, with a plethora of friendly illustrations to help readers grok some of the most brain-bending ideas ever conceived.
Does it succeed? Yes and no. While Hawking offers genuinely accessible context for such complexities as string theory and the ...
continue
|
|
|