Asteróide 2007 TU24 - Passagem próxima a 29 Janeiro

Luis França

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Olha, olha, então o tal asteróide a caminho de Marte afinal tem um "irmão" que passa perto da Terra também? E está nesta página da NASA guardada em cache pelo Google pois já a desligaram, não vá algum curioso espalhar boatos por aí. Imaginem o que poderia acontecer.

link
 

Minho

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Re: Asteróides, cometas e afins - 2008

Está lá na página Impact Probability: 3.9e-08

O que dá:


Impact Probability: 3.9e-08

0.000003900% chance of Earth impact

or

1 in 25,641,000 chance

or

99.99999610% chance the asteroid will miss the Earth


Portanto tudo bem ;)
 

Luis França

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Re: Asteróides, cometas e afins - 2008

Earth_TU24_orbit.jpg


Tom's Asteroid Flybys Webpage

Tom's Asteroid Flybys - 2007 TU24 @ 2008-01-29 07:11:00
Minimum Distance (A.U.) 0.003705
Date/Time of Minimum Distance 2008-01-29 07:11:00
Maximum Predicted Brightness 10.3
Date/Time of Maximum Brightness 2008-01-29 12:00:00
Maximum Apparent Speed (arcseconds/minute) 208.55
Date/Time of Maximum Speed 2008-01-29 10:00:00
H (Absolute Magnitude) 20.2
Oppositions 1
Duration of Observations 99 days
Potentially Hazardous Asteroid? Yes


Minimum Orbital Intersection Distance

The minimum orbital intersection distance (MOID) is the minimum distance between the osculating orbits of two objects. It indicates the closest possible approach of the two objects except where excluded by protective resonance.

As such, the MOID can act as an early warning indicator for collision between an asteroid and a planet. A large MOID between and asteroid and the Earth indicates the asteroid will not collide with Earth in the near term.

Asteroids with a small MOID to Earth should be carefully followed because they can become Earth colliders.

Because of long-range planetary gravitational perturbations and, particularly, close planetary approaches, asteroid orbits change with time.
Consequently, MOID also changes. As a rule of thumb, MOID can change by up to 0.02 AU per century, except for approaches within 1 AU of massive Jupiter, where the change can be large.
 

Luis França

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Re: Asteróides, cometas e afins - 2008

Como vai estar o céu no dia 28 de Janeiro - Marte por cima de Órion, o Holmes perto de Algol, Sedna e TU24 perto de Perseu.

01-28-08comet_holmes_asteroid_tu24.PNG



AA não saias de cá que eu quero ver o céu estrelado...
 

Luis França

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Re: Asteróides, cometas e afins - 2008

AInda consegui extrair estes dados da NASA antes de desligarem a página (pode ser que a reactivem mais tarde).

tu24uh0.gif


NASA has omitted data for TU24 for January 29, 2008! Here are the hard facts that substantiate this.

Here is the link to NASA’s TU24 Planning page.

[link to echo.jpl.nasa.gov]

The first thing that sticks out is the bold quote under the Background section: ‘ADDITIONAL ASTROMETRY IS STILL DESIRABLE FOR THIS OBJECT’

Definition of astrometry: ‘the measurement of the real and apparent motions and the positions of astronomical objects’
Six days out and NASA still does not have a handle on this asteroid.

NASA: ‘nothing is known about TU24's physical properties’.

This is in fact an omission of what they believe is the physical property of TU24? There is a good degree of certainty that TU24 is made of nickel/iron composition and has a strong magnetic field. The strong magnetic field is making it difficult to ascertain with 100% certainty what its physical properties are? Thus they omit what they believe it is because they do not with 100% certainty. It is without question a heavy metal. How does NASA determine the physical composition of stars millions of light year away yet an object a mere six days away ‘nothing is known’? The answer is magnetic interference and lots of it.

NASA: ‘Goldstone observations are scheduled on January 23 and Arecibo observations are scheduled on January 27-28 and February 1-4. Note that Goldstone observations straddle the January 23-24 date boundary.

Notice how there is no observation scheduled from January 29 – January 31.
January 29 is when TU24 is at its closest yet there will not be any observation from NASA of this NEO. You want to know why? Scroll down to the SNR (Signal to Noise Ratio) section. Look at the bottom of the Goldstone observation window. ‘Goldstone DSS-14 will be offline for maintenance from Jan. 25-Feb. 15.’

The declination window of Goldstone DSS-14 runs from 40° south to 80° north. According to the Uncertainties section TU24 maximum declination will be at 64.90 North. So Goldstone DSS-14 could easily observe this NEO the entire time. NASA states in the beginning of the Background section ‘approach on Jan. 29 is the closest for any known Potentially Hazardous Asteroid until 2027.’ Yet they want to do routine maintenance. Doesn’t this strike you as odd and nonsensical use of their equipment given the close proximity of a known NEO?

Now look at the Goldstone SNR table. Do you notice a date missing? January 29, 2008 is missing! There is no data for this date. Why list data leading up to the near miss day and list everything after the near miss day yet leave the near miss distance day data omitted? Does that make any sense?

Goldstone DSS-14, which can track TU24 in its entirety, is down for routine maintenance so NASA can use Arecibo right? Wrong! Arecibo can only track as far north as 40° and as far south as the just below the equator. Look at the SNR Calculation for Arecibo, ‘...too far north for Arecibo to track on Jan. 29-31...’

NASA is going dark on these dates that are the most critical for a known incoming NEO, which by their own admission they know very little about. To validate that we will be in the dark from January 29 to January 31 look at the Track Assignments section.
Tracking stops on the January 28 and resumes February 1. Doesn’t this strike you as very unscientific for a scientific institution?

Clearly there is an omission of data for January 29, 2008 and NASA is going dark on this NEO for 3 days. The fundamental question is why? The answer is that they are looking at this with a 50/50 shot at entering our atmosphere. The three day blackout period is in place should TU24 fragment and thus cause an event that would last over a period of days instead of a one time event. Again they do not know with certainty what will happen.
 

Vince

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Re: Asteróides, cometas e afins - 2008

É uma passagem próxima, mas é mais uma entre muitas outras. O maior problema dos Asteroides nem são os que nós conhecemos mas os milhares de outros que não sabemos sequer da sua existência. Este foi apenas descoberto há 3 meses apesar de andar pelo espaço há milhares ou milhões de anos. Estima-se que todas as semanas haja várias passagens próximas da Terra de Asteróides completamente desconhecidos para nós ou que só os detectamos a quando da passagem. O que querem fazer ? Viver o resto da vida em stress permanente fechados numa capela a rezar ? Nã...... quando acontecer aconteceu, paciência, pode ser daqui a bocado ou pode ser daqui a milhares de anos. Como tudo o resto, daqui a pouco pode haver um grande terramoto, cair-me um vaso na cabeça ou posso ser atropelado ao ir tomar um café. É a vida. E é frágil.

PS: O site da NASA está perfeitamente operacional, está é de vez em quando com problemas de sobrecarga como é natural, pois o site está a ser linkado de muitos outros sites e os media estão a falar do assunto.

Near-Earth Asteroid 2007 TU24 to Pass Close to Earth on Jan. 29 - Should be Observable with Modest Sized Telescopes
Don Yeomans
NASA/JPL Near-Earth Object Program Office
January 22, 2008


Asteroid 2007 TU24, discovered by the Catalina Sky Survey on October 11, 2007 will closely approach the Earth to within 1.4 lunar distances (334,000 miles) on 2008 Jan. 29 08:33 UT. This object, between 150 and 600 meters in diameter, will reach an approximate apparent magnitude 10.3 on Jan. 29-30 before quickly becoming fainter as it moves further from Earth. For a brief time the asteroid will be observable in dark and clear skies with amateur telescopes of 3 inch apertures or larger.

For an interactive illustration of this object's orbit see:

http://ssd.jpl.nasa.gov/sbdb.cgi?sstr=2007+TU24&orb=1

The illustration below is courtesy of amateur astronomer Dr. Dale Ireland from Silverdale, WA. The illustration shows the asteroid's track on the sky for 3 days near the time of the close Earth approach as seen from the city of Philadelphia. Since the object's parallax will be a significant fraction of a degree, observers are encouraged to use our on-line Horizons ephemeris generation service for their specific locations. These personalized ephemeris tables can be generated at: http://ssd.jpl.nasa.gov/horizons.cgi?find_body=1&body_group=sb&sstr=2007 TU24

Given the estimated number of near-Earth asteroids of this size (about 7,000 discovered and undiscovered objects), an object of this size would be expected to pass this close to Earth, on average, about every 5 years or so. The average interval between actual Earth impacts for an object of this size would be about 37,000 years. For the January 29th encounter, near Earth asteroid 2007 TU24 has no chance of hitting, or affecting, Earth.

2007tu24_s.jpg


2007 TU24 will be the closest currently known approach by a potentially hazardous asteroid of this size or larger until 2027. Plans have been made for the Goldstone planetary radar to observe this object Jan 23-24 and for the Arecibo radar to observe it Jan 27-28 and then Feb 1-4. High resolution radar imaging is expected, which may permit later 3-D shape reconstruction.
http://neo.jpl.nasa.gov/news/news157.html
 

HotSpot

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Re: Asteróides, cometas e afins - 2008

O meu presente de natal foi um telescopio e a bem dizer ainda mal peguei naquilo. Vi a lua e fiquei fascinado, também era dificil não ver.

E o TU24 como se vai ver com um telescopio normal como o meu?
 

Luis França

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Quase em simultâneo o TU24 (29 Janeiro) e o WD5 (30 Janeiro) cruzam o céu.

2007 WD5 Mars Collision Effectively Ruled Out - Impact Odds now 1 in 10,000

wd5_unc4.gif






Goldstone radar observations of near-Earth asteroid 2007 TU24 last night were successful. We would like to thank the following stations for providing astrometry after we announced our plans to observe this asteroid:

204 Schiaparelli Observatory Italy
432 Boambee Australia
448 Desert Moon Observatory United States
E12 Siding Spring Australia
I77 CEAMIG-REA Observatory Brazil

The observations reveal an object roughly 250 meters in diameter, with an interesting shape, and strongly suggest that rotates slowly.

The radar astrometry we obtained reduced the asteroid's three-sigma range uncertainty at 00:00:00 UTC on Jan. 24 from about 2/3 of an Earth radius to ~30 meters. Consequently, we have cancelled our request for optical astrometry to support the rest of the radar campaign.

Dr. Lance A. M. Benner
Research Scientist
Jet Propulsion Laboratory

2007tu24.jpg

For the January 29th encounter, near Earth asteroid 2007 TU24 has no chance of hitting, or affecting, Earth.

Mas fiquei com uma dúvida pertinente. Porque é que só neste asteróide (TU24) a Nasa diz o seguinte: não vai atingir nem afectar a Terra? No WD5 nada é dito nesse sentido...será porque não há vida em Marte? :D
 

Vince

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Um video fenomenal do Phil Plait acerca da paranoia de medo, disparates e mentiras que os doomsayers (aka, mensageiros do apocalipse) estão a espalhar na Net por causa do TU27:

 
Editado por um moderador:

Vince

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Mas fiquei com uma dúvida pertinente. Porque é que só neste asteróide (TU24) a Nasa diz o seguinte: não vai atingir nem afectar a Terra? No WD5 nada é dito nesse sentido...será porque não há vida em Marte? :D

O WD5 despertou uma enorme curiosidade na comunidade cientifica, muito superior ao TU24 que passará mais próximo de nós, porque após a sua descoberta nos primeiros cálculos chegou a ter boas probalidades de colidir com Marte.

Assistir e estudar um impacto de um asteroide de 50m, provavelmente idêntico ao da explosão de Tunguska/Sibéria em 1908, e num planeta tão próximo como Marte, seria extremamente valioso e uma oportunidade única para a ciência estudar os efeitos de tal colisão. Até porque colisões como esta de 50m já são muito mais frequentes na Terra do que asteróides gigantes.
Posteriores cálculos diminuiram consideravelmente as probalidades de impacto e naturalmente o interesse por este calhau também diminuiu na mesma proporção.




O meu presente de natal foi um telescopio e a bem dizer ainda mal peguei naquilo. Vi a lua e fiquei fascinado, também era dificil não ver.
E o TU24 como se vai ver com um telescopio normal como o meu?


Nos variados artigos sobre ele dizem que sim, que é possível vê-lo com um telescópio modesto, mas penso que não será nenhuma visão excepcional, pois tem 500m de diametro e passará a 538,000 km da Terra.
A ver se o astrofotógrafo do forum sabe de algo mais sobre o assunto.

A primeira fotografia conseguida até ao momento é esta:

tu24-20080125-browse.jpg


NASA Scientists Get First Images of Earth Flyby Asteroid
January 25, 2008

Scientists at NASA's Jet Propulsion Laboratory in Pasadena, Calif., have obtained the first images of asteroid 2007 TU24 using high-resolution radar data. The data indicate the asteroid is somewhat asymmetrical in shape, with a diameter roughly 250 meters (800 feet) in size. Asteroid 2007 TU24 will pass within 1.4 lunar distances, or 538,000 kilometers (334,000 miles), of Earth on Jan. 29 at 12:33 a.m. Pacific time (3:33 a.m. Eastern time).

"With these first radar observations finished, we can guarantee that next week's 1.4-lunar-distance approach is the closest until at least the end of the next century," said Steve Ostro, JPL astronomer and principal investigator for the project. "It is also the asteroid's closest Earth approach for more than 2,000 years."

Scientists at NASA's Near-Earth Object Program Office at JPL have determined that there is no possibility of an impact with Earth in the foreseeable future.

Asteroid 2007 TU24 was discovered by the NASA-sponsored Catalina Sky Survey on Oct. 11, 2007. The first radar detection of the asteroid was acquired on Jan. 23 using the Goldstone 70-meter (230-foot) antenna. The Goldstone antenna is part of NASA's Deep Space Network Goldstone station in Southern California's Mojave Desert. Goldstone's 70-meter diameter (230-foot) antenna is capable of tracking a spacecraft traveling more than 16 billion kilometers (10 billion miles) from Earth. The surface of the 70-meter reflector must remain accurate within a fraction of the signal wavelength, meaning that the precision across the 3,850-square-meter (41,400-square-foot) surface is maintained within one centimeter (0.4 inch).

Ostro and his team plan further radar observations of asteroid 2007 TU24 using the National Science Foundation's Arecibo Observatory in Puerto Rico on Jan. 27-28 and Feb. 1-4.

The asteroid will reach an approximate apparent magnitude 10.3 on Jan. 29-30 before quickly becoming fainter as it moves farther from Earth. On that night, the asteroid will be observable in dark and clear skies through amateur telescopes with apertures of at least 7.6 centimeters (three inches). An object with a magnitude of 10.3 is about 50 times fainter than an object just visible to the naked eye in a clear, dark sky.

Scientists working with Ostro on the project include Lance Benner and Jon Giorgini of JPL, Mike Nolan of the Arecibo Observatory, and Greg Black of the University of Virginia.

NASA detects and tracks asteroids and comets passing close to Earth. The Near Earth Object Observation Program, commonly called "Spaceguard," discovers, characterizes and computes trajectories for these objects to determine if any could be potentially hazardous to our planet. The Arecibo Observatory is part of the National Astronomy and Ionosphere Center, a national research center operated by Cornell University, Ithaca, N.Y., for the National Science Foundation. JPL is a division of the California Institute of Technology in Pasadena.

For more information, visit http://neo.jpl.nasa.gov .
 

Luis França

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Asteroid 2007 TU24 hurtles past Earth

Mike Nolan, head of radar astronomy at the Puerto Rico observatory, said: “We have good images of a couple of dozen objects like this, and for about one in ten, we see something we’ve never seen before. We really haven’t sampled the population enough to know what’s out there.”

Tomorrow, the 2007 WD5, another asteroid, is due to shoot within 16,250 miles of Mars. Initial calculations had suggested the object may collide with the red planet, but that has now been virtually discounted.

Measuring about 50 metres across, it would have delivered an impact equivalent to a three-megatonne nuclear weapon, which could have been monitored by European and US satellites positioned nearby.