Close encounters #2: Asteroiden scheren langs de aarde

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Asteroide 2005 YU55 in aantocht
Op 8 november 2011 zal de vrij grote asteroïde 2005 YU55 de aarde in astronomische termen op een haartje na voorbij scheuren. 2005 YU55 zal op zijn dichtstbijzijnde punt slechts ongeveer 324.604 kilometer en een sjiek van de aarde verwijderd zijn, en dat is dichterbij dan onze maan. Want de maan bevindt zich zelfs tijdens het perigeum, het punt waar ze het dichtste bij de aarde staat, op een afstand van 363.345 kilometer.

De asteroïde 2005 YU55 zal met zijn breedte van circa 400 meter en een gewicht van circa 55 miljoen ton de grootste massieve rotsmassa ooit geïdentificeerd zijn die de aarde zo dicht zal naderen. Tot in 2028 alleszins. Ondanks de grote massa en de dichte nadering tot de aarde zal de aantrekkingskracht van 2005 YU55 op onze aarde te verwaarlozen zijn.

Desalniettemin blijft 2005 YU55 een potentieel gevaarlijk object (potentially hazardous object). Mocht de asteroïde op aarde inslaan dan zou er een krater van 10 kilometer breed en 600 meter diep achterblijven. De kracht van de impact zou te vergelijken zijn met 65.000 atoombommen. De eerstkomende 100 jaar hoeven we echter geen rekening houden met een eventuele impact.

De asteroïde 2005 YU55 werd in december 2005 ontdekt door Dr. Robert S. McMillan, hoofd van het Spacewatch Program bij de Universiteit van Arizona. 2005 YU55 doet 14 jaar over zijn baan rond de zon en zal de komende eeuw niet in botsing komen met de aarde.

Asteroid 2005 YU55 approaching earth

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Op woensdag 26 oktober 2011 11:19 schreef Frutsel het volgende:
Vroeg ik me eerder ook al af...bij helder weer, op een donkere plek en weten waar je moet kijken zou het mogelijk moeten kunnen zijn verwacht ik..maar zeker weten doe ik het niet

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Op woensdag 26 oktober 2011 11:46 schreef Frutsel het volgende:
of stiekum toch tegen de aardbol

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Op woensdag 26 oktober 2011 11:46 schreef Frutsel het volgende:
of stiekum toch tegen de aardbol

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Meteor over Canada
A meteor that lit up the night sky of western Saskatchewan and eastern Alberta Tuesday night likely landed in the North Battleford area. Those who saw the meteor as it passed through the Earth's atmosphere about 9:45 p.m. described it as a streak or a bright flash of light across the sky. "I get up, I look east and there was a great ball of fire coming out of the sky. It was kind of an orange-yellow on the first part of the ball and then it had a green-reddish tail on the end of it," eyewitness Shane Taylor said. Alan Hildebrand, a professor in the department of geoscience at the University of Calgary, confirmed the flash was a meteor. He says video of the meteor's path was captured in Calgary and Lucky Lake. Hildebrand says the chunk of asteroid broke up on impact with the Earth's surface and weighed about 100 kilograms.

Meteor_20120221_2040.wmv

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Op woensdag 22 februari 2012 13:52 schreef Frutsel het volgende:

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Meteor_20120221_2040.wmv

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Asteroide scheert vlak langs de aarde in februari 2013
Volgend jaar zal een asteroïde vlak langs onze planeet scheren. Op 15 februari 2013 zal steenhomp 2012DA14 op 'slechts' 29.000 kilometer afstand de Aarde passeren. Dat is dichter bij het aardoppervlak dan bijvoorbeeld de geostationaire satellieten die in een baan rond de Aarde zweven. Die draaien een baan op een kleine 36.000 kilometer hoogte.

Het hemellichaam is tussen 40 en 95 meter groot. Het is ontdekt door de Spaanse sterrenwacht La Sagra. Astronomen overal ter wereld houden 2012 DA14 nu in het oog om de precieze grootte en traject te weten te komen. De planetoïde maakt deel uit van een klasse asteroïden waarvan vele potentieel met ons in botsing kunnen komen.

Wetenschappers volgen ook een asteroïde die in 2040 een bedreiging zou kunnen voor onze planeet. Dat meldt de gezaghebbende website space.com. Het gaat om planetoïde 2011 AG5 die ongeveer 140 meter groot is. Het hemellichaam kan in 2040 zo dichtbij onze planeet komen dat sommige wetenschappers een discussie willen opstarten over een manier om het ding af te wenden, aldus de site.

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2011 AG5 may pose threat in 2040
Scientists are keeping a close eye on a big asteroid that may pose an impact threat to Earth in a few decades.

The space rock, which is called 2011 AG5, is about 460 feet (140 meters) wide. It may come close enough to Earth in 2040 that some researchers are calling for a discussion about how to deflect it.

Talk about the asteroid was on the agenda during the 49th session of the Scientific and Technical Subcommittee of the United Nations Committee on the Peaceful Uses of Outer Space (COPUOS), held earlier this month in Vienna.

A UN Action Team on near-Earth objects (NEOs) noted the asteroid’s repeat approaches to Earth and the possibility — however remote — that 2011 AG5 might smack into our planet 28 years from now.

The object was discovered in January 2011 by Mount Lemmon Survey observers in Tucson, Ariz. While scientists have a good bead on the space rock's size, its mass and compositional makeup are unknown at present. [The 7 Strangest Asteroids in the Solar System]

"2011 AG5 is the object which currently has the highest chance of impacting the Earth … in 2040. However, we have only observed it for about half an orbit, thus the confidence in these calculations is still not very high," said Detlef Koschny of the European Space Agency’s Solar System Missions Division in Noordwijk, The Netherlands.

"In our Action Team 14 discussions, we thus concluded that it not necessarily can be called a ‘real’ threat. To do that, ideally, we should have at least one, if not two, full orbits observed," Koschny told SPACE.com.

Koschny added that the Action Team did recommend to the NEO Working Group of COPUOS to use 2011 AG5 as a "desktop exercise" and link ongoing studies to the asteroid.

"We are currently also in the process of making institutions like the European Southern Observatory aware of this object," Koschny said. "We hope to make the point that this object deserves the allocation of some special telescope time."

Non-zero impact probability

The near-Earth asteroid 2011 AG5 currently has an impact probability of 1 in 625 for Feb. 5, 2040, said Donald Yeomans, head of the Near-Earth Object Observations Program at NASA’s Jet Propulsion Laboratory in Pasadena, Calif.

This impact probability isn't set in stone, however. So far, researchers have been able to watch the asteroid for just a short time — the first nine months of 2011 — and the numbers may change after further observation, Yeomans told SPACE.com. [Photos: Asteroids in Deep Space]

"Fortunately, this object will be observable from the ground in the 2013-2016 interval," Yeomans said. In the very unlikely scenario that its impact probability does not significantly decrease after processing these additional observations, "there would be time to mount a deflection mission to alter its course before the 2023 keyhole," he added.

Keyholes are small regions in space near Earth through which a passing NEO's orbit may be perturbed due to gravitational effects, possibly placing it onto a path that would impact Earth.

Prudent course of action

2011 AG5 may zip through such a keyhole on its close approach to Earth in February 2023, which will bring the asteroid within 0.02 astronomical units (1.86 million miles, or 2.99 million kilometers) of Earth.

One astronomical unit is the average distance between Earth and sun, which is approximately 93 million miles (150 million km).

According to a JPL estimate, the 2023 keyhole — through which 2011 AG5 must pass in order for there to be a real chance of an Earth impact in 2040 – is roughly 62 miles (100 km) wide.

"Although this keyhole is considerably larger than the Apophis keyhole in 2029, it would still be a straightforward task to alter the asteroid’s trajectory enough to miss the keyhole – and hence the impact in 2040," Yeomans noted, referring to the asteroid Apophis, which could threaten Earth in 2036 if it zips through a keyhole in 2029.

"The prudent course of action is then to wait at least until the 2013 observations are processed before making any preliminary plans for a potential deflection mission," Yeomans said.

Processing additional observations in the 2013-2016 time period, he added, "will almost certainly see the impact probability for 2011 AG5 significantly decrease."

Wanted: Higher-fidelity assessment

"Yes, the object 2011 AG5 was much discussed at the AT 14 meetings last week, but perhaps prematurely," said Lindley Johnson, NASA’s NEO Observations Program Executive in Washington, D.C.

Johnson said NEO watchers have flagged the asteroid "as one we should keep an eye on." At present, he said, while researchers have better preliminary orbit data for 2011 AG5 than for many other asteroids in the NEO catalog, "we have only medium confidence in the derived orbital parameters."

"Fortunately, we are confident our uncertainties in the current orbit model will be reduced when we will have good observation opportunities in September 2013 with the larger follow-up assets," Johnson told SPACE.com. Observing opportunities are even better, he added, starting in November 2015 and for several months thereafter.

"This, in turn, will enable us to better assess the likelihood of any ‘keyhole’ passage in 2023 and therefore a much higher fidelity assessment of any impact probability for the 2040 time frame," Johnson said. [5 Reasons to Care About Asteroids]

"So, rather than a need to immediately jump to space mission solutions, the situation with 2011 AG5 shows the value of finding potentially hazardous objects early enough so that there is time for a methodical approach of observation and assessment as input to any need for an expensive spacecraft mission," Johnson said. "A more robust survey capability would improve the data available to make such assessments."

Decision challenge

Long-time NEO specialist and former Apollo astronaut Russell Schweickart played an active role in the dialogue about 2011 AG5. He represented the Association of Space Explorers (ASE) Committee on Near Earth Objects and presented to the Action Team an analysis of the situation with 2011 AG5.

The space rock presents a "decision challenge" to the international community, Schweickart suggested, "in the unlikely chance that its current low, but significant probability of impacting Earth in 2040 continues to increase after additional tracking becomes available."

Schweickart spotlighted a rough Association of Space Explorers analysis of the options to deflect the asteroid in the future, in the unlikely scenario that the Earth impact probability continues to increase.

He also provided to the Action Team several new appraisals of options for deflection of asteroid 2011 AG5 to avoid a potentially dangerous Earth encounter in 2040.

Delayed deflection campaign

A decision date for a keyhole deflection is very soon, if not now, Schweickart suggested. Asteroid 2011 AG5 represents an actual threat that underscores the need for a NEO hazard decision-making structure within the UN COPUOS, he said.

Based on the latest analysis, Schweickart reported, a deflection campaign delayed until after the 2023 close approach appears marginally possible, as long as a decision to commit is made immediately thereafter.

In the low-probability case in which the impact threat of the asteroid persists beyond its 2013 apparition, "should a keyhole deflection campaign be foregone — for whatever reason — the international community may be faced with the difficult decision of choosing between an expensive multikinetic impactor or a nuclear explosive to prevent an impact should the NEO indeed pass through the keyhole," Schweickart said.

The timelines that would be required to mount a successful deflection of the asteroid, Schweickart told SPACE.com, might be challenging.

But first things first — researchers stress that more study of the asteroid’s trajectory is called for. The next tracking opportunities of 2011 AG5 will occur in September 2013, and then again in November 2015.

NASA chief: We still have time

In response to a letter from Schweickart regarding 2011 AG5, NASA Administrator Charles Bolden said that 2011 AG5 is "high on NASA’s list of NEOs to monitor for impact hazard potential," adding that "we take these duties very seriously."

Bolden also noted the opportunities for highly accurate ground-based observations in the near future.

"Based on these observations, a more informed assessment can then be made on the need for any type of mitigation," he said.

Bolden also remarked that the asteroid makes an apparition in 2015, more than seven years before the close keyhole passage in 2023 that could set in motion an Earth impact in the 2040 time frame.

"As a point of comparison, NASA’s Deep Impact mission [the Deep Impact probe smashed into comet Tempel 1 in July 2005] was conducted in six years from selection to impact under much less urgency, demonstrating the adequacy of a seven-year period for any necessary response," Bolden said.

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Bright meteorite over Britain
Police forces say have they received a number of calls reporting what is believed to have been a meteorite.

Reports of a "bright light" and an "orange glow" came in across the north of England and Scotland at about 21:40 GMT amid fears a plane had crashed.

The Met Office tweeted: "Hi All, for anyone seeing something in the night sky, we believe it was a meteorite."

Durham Police said air traffic control had confirmed there had not been any incidents of aircraft in difficulties.

A force spokeswoman said: "The sightings are believed to be either an asteroid burning out or similar which has been restricted to the upper atmosphere only."

Meteorites are large rocks originating in outer space, which, when they enter the Earth's atmosphere, tend to heat up and emit light, forming a fireball, also known as a shooting star.
'Ball of fire'

Professor David Whitehouse, an astronomer, said: "Occasionally you get a very big piece of debris coming into the Earth's atmosphere and this causes a fireball and, when you see this fireball breaking up, you're seeing the wreckage of a planet that couldn't form properly when the solar system was young and a bit of rock that has been orbiting the Sun for perhaps thousands of millions of years."

Adrian West, of Meteorwatch, said he had seen reports of sightings from Scotland to Devon.

He said he saw it in Berkshire and believed it could have gone down in the English Channel or the Bay of Biscay.
Adam Hepworth, from Helensburgh, in Argyll, told the BBC: "I was leaving work and getting into my car and I noticed a really bright light moving slowly across the sky.

"At first I thought it was a sky lantern but then I realised it couldn't have been due to the speed that it was moving. I then thought perhaps it is a plane that had caught fire.

"I knew it was really odd and sat there for a few minutes just staring at it."

Grampian Police said many people had reported seeing a "flare or a bright object with a tail", while Dumfries and Galloway Constabulary said it had received reports of a "large ball of fire in the sky".

Hundreds of people tweeted about what they had seen and the Kielder Observatory, in Northumberland, said a "huge fireball" had been seen travelling from north to south over the county.

The Observatory posted on Twitter: "Of 30 years observing the sky #fireball best thing I have ever seen period."

'Red sparks'

One witness, from Cheshire, told the BBC: "It was about the size of a football... and there was bright red large sparks flying off it and also it had a tail as well."

Another, who called BBC Radio 5 live's Stephen Nolan programme, said: "I looked up and saw these two huge tails of light coming off it and I thought it was a plane on fire going down into Edinburgh.

"It was massive, there was the red at the back of it, then these two huge white tails and then these blue bits at the very end."

Meteor Flashes Across British Skies 03/03/2012

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Watch the skies Februari 2013
Scientists are predicting that the asteroid 2012 DA14 has a good chance of colliding with Earth in eleven months. Watch the skies in February 2013!

According to RT, NASA has confirmed that the 60 meter (or 197 feet) asteroid, which was spotted by Spanish stargazers in February this year, has a good chance of colliding with earth.

The scientists suggest confronting this asteroid with either big guns or, more strangely, with paint. The problem with either option is that there is no time to build a spaceship for the operation.
A spaceship could either shoot the asteroid down or simply crash into it - this would either break it into pieces or throw it off course.

NASA expert David Dunham suggested: “We could paint it.”

The paint would change the asteroid's ability to reflect sunlight, alter its spin and change its temperature. However, even taking the asteroid off course could be dangerous when it returns in 2056, according to Aleksandr Devaytkin the head of the observatory in Russia’s Pulkovo, as told to Izvestia in Russia recently.

The asteroid's closest approach to earth is scheduled for 15 February 2013, when they predict that the distance between it and earth will be under 27,000 km (16,700 miles).
With the asteroid zooming that low, it will be too late to do anything with it besides trying to predict its final destination and the consequences of impact.

However, NASA's David Dunham did say: “The asteroid may split into pieces entering the atmosphere. In this case, most parts of it will never reach the planet’s surface.”
But theories are that if the entire asteroid did crash into the planet, the impact will be as hard as in the Tunguska blast, which in 1908 knocked down trees over a total area of 2,150 sq km (830 sq miles) in Siberia.

So keep your head down and watch the skies.

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Op dinsdag 28 februari 2012 21:21 schreef Frutsel het volgende:
Grote kans dat enorm rotsblok Aarde in 2040 ramt

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Op woensdag 29 februari 2012 09:45 schreef lipjes het volgende:
imho vind ik 140meter niet echt heel erg groot
als dat een impact wordt, is het nog maar de vraag hoeveel er van over is zodra hij door de damnkring is.
140 meter kan nog wel redelijk wat schade aanrichten, maar globaal-levensbedreigend?

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Op maandag 5 maart 2012 00:24 schreef -CRASH- het volgende:

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Al breekt ie in stukken.....
En dan moet je eens bedenken dat de veroorzaker van de Arizona crater maar 45 meter groot was.

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Op maandag 5 maart 2012 14:08 schreef lipjes het volgende:

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Het zal inderdaad wel een schade en slachtoffers geven, maar een global killer? nee.
De schade kan hooguit vergroot worden door een oceanische impact.
Dat kan dan wel weer een enorme golf geven, maar dan zitten wij in NL nog vrij veilig aangezien wij de UK hebben als golfbreker.