Asteróides, cometas e meteoritos - 2008

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Arecibo Observatory Spies An Asteroid Close To The Sun

asteroid-3200-phaethon-arecibo-radar-bg.jpg


The asteroid - if it is one - travels close to the sun. But here's the catch: Astronomers suspect that Phaethon may actually be a comet and a possible parent of the Geminid meteor shower, which annually causes many streams of shooting stars between now and Christmas.

Phaethon and other asteroids that have trajectories strongly affected by sunlight, sun shape and general relativity effects are being studied by Jean-Luc Margot, Cornell assistant professor of astronomy and Jon Giorgini, of the NASA Jet Propulsion Laboratory, Pasadena, Calif.. Mike Nolan, an Arecibo staff scientist, conducted the observation.


Terá alguma similaridade com este objecto que passou perto do Sol recentemente?

20071231_003754_d7c2A.jpg
 

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Deadly asteroid may hit Mars soon

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The asteroid, known simply as 2007 WD5, was discovered in the constellation Taurus on November 20, 19 days after passing near the Earth at an apparent magnitude of +20. That is about 400,000 times fainter than most people can see with the naked eye on a dark night.

Early observations of the asteroid caused excitement amongst the scientific community when it was estimated as having as high as a 1 in 75 chance of colliding with Mars on January 30, 2008. Wikipedia estimated such chances as 1 in 25.

However, by January 9, additional observations allowed NASA's Near Earth Object Program (NEOP) to narrow the field of uncertainty, resulting in only a 1-in-10,000 chance of impact.




Atenção que este asteróide (2007 WD5) não é aquele que a partir de 18 a 30 de Janeiro passa a uma distância Terra-Lua da Terra (2007 TU24).
 

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Martians in for some contact sport

Mark January 31 in your diary. If anyone invites you to a barbecue on Mars on that day, say no. You might wind up roasted yourself, because as you read this, a rogue asteroid is hurtling towards the Red Planet, and you wouldn't want to be underneath it when it gets there.
Dubbed 2007WD5 by astronomers, the asteroid doesn't sound enormous at 50 metres wide, but hitting the ground at 45,000 kilometres an hour a 50-metre chunk of rock can wreak a good deal of havoc.
It is a timely reminder that these things can, and do, plough into the Earth as well, and it's spooky to think that the last time one did was almost 100 years ago, on June 30, 1908, when vast areas of Siberian forest were totalled in "the Tunguska Event".

That titanic explosion was a mystery for decades, but it is now thought that it was caused by an asteroid very similar to 2007WD5. Had it landed a few hours later, say, on London or Berlin, the history of the 20th century would have been very different.



Baralha e dá de novo! E ninguém fala do TU24 que no dia 28-29 passa mais perto da TERRA. O de Marte vai para lá. E o "nosso"?
 

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Mysterious hole in pond sparks speculation of a meteorite

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Spruce Grove residents woke up yesterday to a mysterious octopus-shaped hole in a frozen golf-course pond.
A hole about 1.5 metres in diameter was visible yesterday on the pond at The Links at Spruce Grove, along with at least 20 splash marks - the longest about six metres.
"It wasn't there (Friday)," said neighbour Tina Danyluk, whose house backs onto the pond.
She suspects it might have been a meteorite.
Whatever it was, it had to have followed a high trajectory based on "how the splash spread," Danyluk said.
 

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Re: Asteróides, cometas e afins - 2008

boas

foi em 2007

Após meteorito, doença misteriosa afeta peruanos

Os moradores da localidade peruana de Puno, localizada a cerca de 1.300 km ao sul de Lima, estão sofrendo de uma misteriosa doença depois que um meteorito caiu na região, abrindo uma cratera de 30 m de diâmetro, informaram autoridades regionais.

» Meteorito cai e abre cratera no Peru

Segundo o responsável pelo departamento de saúde de Puno, Jorge Lopez, desde o incidente, ocorrido pouco antes da meia-noite do último sábado, as pessoas estão reclamando de dores de cabeça e de vômitos causados por um "cheiro estranho".

Os sete policiais que foram checar a cratera também estão doentes e tiveram de receber oxigênio antes de serem hospitalizados, de acordo com Lopez. Equipes de especialistas foram enviadas ao local da cratera, que tem cerca de 6 m de profundidade.

"Bolhas de água fervente começaram a sair do buraco e partículas de rocha e cinzas foram encontradas nas proximidades. Os moradores estão preocupados", disse uma autoridade da região.

http://noticias.terra.com.br/ciencia/interna/0,,OI1916543-EI302,00.html

abraços
 

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Researchers Observe Extra-galactic Meteor

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The common belief is that all meteors come from inside our solar system. Most meteors are thought to be pieces of comet dust or fragments of asteroids that enter Earth’s atmosphere and burn up before they hit the ground, leaving a fiery trail we call “shooting stars.” But a recent observation might put a hole in the idea that these space rocks only come from the immediate vicinity of our solar system. A group of astronomers in Russia believe they observed a meteor of extragalactic origin.

On July 28, 2006, Victor Afanasiev from the Russian Academy of Sciences was making observations using a 6 meter telescope equipped with a multi-slit spectrometer. By chance, he observed the spectrum of a faint meteor as it burned up in the Earth’s atmosphere, and in looking at the data, found several anomalies. First was the speed at which the meteor was traveling. This meteor hit the atmosphere at about 300 kilometers per second, which is quite extraordinary. Only about 1% of meteors have velocities above 100 km/sec, and no previous meteor observations have yielded velocities of several hundred km/s. So where did this one come from?

Since the Earth moves around the galactic center at about 220 km/s, Afanasiev says the meteor’s origin cannot easily be explained by reference to the Milky Way. It appears that it came from the direction in which the Earth and the Milky Way is travelling towards the center of our local group of galaxies. “This fact leads us to conclude that we observed an intergalactic particle, which is at rest with respect to the mass centroid of the Local Group and which was “hit” by the Earth,” Afanasiev and his team say in their paper.
 

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ASTEROID FLYBY:

That was close. Yesterday, newly discovered asteroid 2008 CT1 flew past Earth only 72,000 miles (0.3 lunar distances) away. Had it struck our planet, the 13-meter wide space rock (similar in size to a school bus) would have done little damage, probably exploding in the atmosphere and peppering some lonely stretch of ocean with meteorites.

Soma e segue...:rolleyes:


Watch: Fireball over Polk County

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Re: Asteróides, cometas e afins - 2008

Estudantes israelitas propõem desviar asteróide que poderia vir a colidir com a Terra

Estudantes do Instituto Tecnológico de Haifa, no norte de Israel, propuseram à Nasa desviar o asteróide “Apophis” da sua trajectória, com uma sonda espacial, em caso de necessidade.

Com 250 metros de diâmetro, o “Apophis” foi detectado há cerca de quatro anos e prevê-se que a sua trajectória irá passar relativamente perto da Terra entre 2029 e 2036. Segundo os cálculos iniciais da Nasa, a probabilidade de impacto, a 13 de Abril de 2029, seria de 2,7 por cento. Um asteróide do tamanho do "Apophis" que colidisse com a terra causaria um efeito equivalente ao de 20 mil bombas atómicas.

O projecto dos estudantes israelitas, apresentado num concurso convocado pela agência espacial norte-americana, propõe, segundo o diário “Yediot Aharonot”, uma primeira aproximação em 2020 para que se possa vigiar a sua trajectória. Numa segunda fase, a sonda regressaria a uma órbita próxima da Terra onde em caso de necessidade, realizaria uma nova aproximação em 2025 para alterar a sua trajectória.

Segundo Alexander Kogan, o supervisor do projecto, um impacto directo do “Apophis” com a terra causaria a destruição absoluta num raio de 200 quilómetros.

Descoberto em 2004, o nome “Apophis” tem a sua origem no nome do deus egípcio da destruição e da morte.

In: Publico
 

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Re: Asteróides, cometas, meteoros e meteoritos - 2008

PACIFIC FIREBALL: On Tuesday morning, Feb. 19th, at approximately 5:30 a.m. Pacific time, people in Washington, Oregon, Idaho and Montana witnessed a spectacular fireball. It exploded not once but twice in midair, casting shadows and rivaling city lights. Many onlookers wondered if spy satellite USA 193 had been shot down. No, it was a small asteroid breaking up in Earth's atmosphere, a surprisingly common event. Reports of meteorites hitting the ground remain unconfirmed; stay tuned for updates

"I did not see the fireball itself, but I did observe two bright flashes over the eastern horizon like transformer explosions," reports climatologist Jan Curtis of Portland, Oregon. "They were as bright as city lights." Much is uncertain about this event. It was probably a small asteroid breaking up in Earth's atmosphere.

http://spaceweather.com/comments/indiv_thread.php?thread_id=30

 
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Outro video interessante


Meteor wakes up Mid-Columbia early birds


A bright blue meteor with an orange and yellow fireball tail startled many Mid-Columbia residents and people as far away as the Canadian province of Alberta on Tuesday morning.
Some also heard a sonic boom after the meteor lit up the sky at 5:31 a.m.

"The light was so ... close to me and so bright, I swerved off the road," said Dante Martinez of Richland. "I was shaking because it was so close. I've never witnessed or seen anything so bright ever. ... It was so super bright, my eyes had to adjust a little."
Martinez was on his way to work in Umatilla and was by the bridge near McNary Dam when he saw the light, which was about a half-mile wide, he said.
"My whole life I've always been looking in the sky, always looking for things," he said. "I've seen meteorites and falling stars and what not, but I've never seen anything like this."
A number of pilots reported seeing the meteor streaking through the sky from Boise into Washington and one initially said it landed in Adams County around 5:45 a.m., but officials with the Federal Aviation Administration later said that report was erroneous.
If a meteor crashed into Earth, it likely did so in the southeast area of the state, said Roy Gephart, an earth scientist with the Pacific Northwest National Laboratory and an avid amateur astronomer. He said the meteor was traveling in a northwest to southeast direction and "when it disintegrated and exploded, it was low in the southeast sky," he said.


Meteor Streaks over the Pacific Northwest Sky

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Re: Asteróides, cometas, meteoros e meteoritos - 2008

Triple Asteroid Spotted in "Near-Earth" Space


Triple Asteroid System (Yes, That Means Mini-Moons) Spotted Near Earth
By John Borland February 14, 2008

Researchers using the massive Arecibo telescope in Puerto Rico have discovered the first observed example of a triple asteroid – a center body, orbited by two smaller ones – in near-Earth space.

It's possible this is going to spawn a whole new LOLasteroid genre. But in fact, there are serious scientific issues at stake here.
Triple asteroid systems aren't uncommon in the belt between Mars and Jupiter, but this is the first one noted relatively near Earth, where the actual shapes of the objects can be seen.
Researchers say the central body is a rock about 1.5 miles in diameter. The larger of the "moons" is about half that size, and the smallest just 1000 feet across.
"This discovery has extremely important implications for ideas about the origins of near-Earth asteroids and the processes responsible for their physical properties," said (Cornell University astronomer Michael) Nolan. "Double, or binary, asteroid systems are known to be fairly common - about one in six near-Earth asteroids is a binary - but this is the first near-Earth triple system to be discovered."

The triple-rock system should provide insight into how near-Earth asteroid systems evolve over time, and whether multiple-asteroid formations can form nearby, or were collected together in the main asteroid belt, the researchers say.
The asteroid system, known as 2001 SN263, was viewed by Arecibo on Feb. 11, when it was about 7 million miles from Earth.
First near-Earth triple asteroid discovered by Arecibo Observatory astronomers - a mere 7 million miles from Earth [Cornell press release]