Posted on 12/26/2004 8:33:58 PM PST by shadowman99
Update, Dec. 25, 9:47 p.m. ET: The risk of an impact by asteroid 2004 MN4 went up slightly on Saturday, Dec. 25. It is now pegged at having a 1-in -45 chance of striking the planet on April 13, 2029. That's up from 1-in-63 late on Dec. 24, and 1-in-300 early on Dec. 24.
Astronomers still stress that it is very likely the risk will be reduced to zero with further observations. And even as it stands with present knowledge, the chances are 97.8 percent the rock will miss Earth.
Update, Dec. 24, 10:19 p.m. ET: An asteroid that has a small chance of hitting Earth in the year 2029 was upgraded to an unprecedented level of risk Friday, Dec. 24. Scientists still stress, however, that further observations will likely show the space rock won't be on a collision course with the planet.
The risk rating for asteroid 2004 MN4 was raised Friday by NASA and a separate group of researchers in Italy.
The asteroid's risk rating a possible impact scenario on April 13, 2029 has now been categorized as a 4 on the Torino Scale. The level 4 rating -- never before issued -- is reserved for "events meriting concern."
The Dec. 24 update from NASA stated:
"2004 MN4 is now being tracked very carefully by many astronomers around the world, and we continue to update our risk analysis for this object. Today's impact monitoring results indicate that the impact probability for April 13, 2029 has risen to about 1.6 percent, which for an object of this size corresponds to a rating of 4 on the ten-point Torino Scale. Nevertheless, the odds against impact are still high, about 60-to-1, meaning that there is a better than 98 percent chance that new data in the coming days, weeks, and months will rule out any possibility of impact in 2029."
With a half-dozen or so other asteroid discoveries dating back to 1997, scientists had announced long odds of an impact -- generating frightening headlines in some cases -- only to announce within hours or days that the impact chances had been reduced to zero by further observations. Experts have said repeatedly that they are concerned about alarming the public before enough data is gathered to project an asteroid's path accurately.
Asteroid 2004 MN4 is an unusual case in that follow-up observations have caused the risk assessment to climb -- from Torino level 2 to 4 -- rather than fall.
An edited version of the 2004 MN4 story originally posted on SPACE.com at 9:58 a.m. ET on Dec. 24:
Scientists said Thursday that a recently discovered asteroid has a chance of hitting Earth in the year 2029, but that further observations would likely rule out the impact scenario.
The asteroid is named 2004 MN4. It was discovered in June and spotted again this month. It is about a quarter mile (400 meters) wide. That's bigger than the space rock that carved meteor crater in Arizona, and bigger than one that exploded in the air above Siberia in 1908, flattening thousands of square miles of forest. If an asteroid the size of 2004 MN4 hit the Earth, it would do considerable localized or regional damage. It would not cause damage on a global scale. Scientists stressed, however, that the rock would likely miss the planet. A statement was released by NASA asteroid experts Don Yeomans, Steve Chesley and Paul Chodas. "The odds of impact, presently around 1-in-300, are unusual enough to merit special monitoring by astronomers, but should not be of public concern," the scientists said. "These odds are likely to change on a day-to-day basis as new data are received. In all likelihood, the possibility of impact will eventually be eliminated as the asteroid continues to be tracked by astronomers around the world." The scientists project an asteroid's future travels based on observations of its current orbit around the Sun. On computer models, the future orbits are not lines but rather windows of possibility. The orbit projections for 2004 MN4 on April 13, 2029 cover a wide swath of space that includes the location where Earth will be. Additional observations will allow refined orbit forecasts -- more like a line instead of a window. The asteroid will be easily observable in coming months, so scientists expect to figure out its path.
Most asteroids circle the Sun in a belt between Mars and Jupiter. But some get gravitationally booted toward the inner solar system. The 323-day orbit of 2004 MN4 lies mostly within the orbit of Earth. The asteroid approaches the Sun almost as close as the orbit of Venus. It crosses near the Earth's orbit twice on each of its passages about the Sun. 2004 MN4 was discovered on June 19 by Roy Tucker, David Tholen and Fabrizio Bernardi of the NASA-funded University of Hawaii Asteroid Survey. It was rediscovered on Dec. 18 from Australia by Gordon Garradd of the Siding Spring Survey. More than three dozen observations have been made, with more expected to roll in from other observatories this week.
It has been a busy stretch for asteroid scientists. Earlier this week, researchers announced that a small space rock had zoomed past Earth closer than the orbits of some satellites.
Thats what I meant; survivors from a comet and/or large asteroid strike are remote in the extreme. Those that DO survive had best be prepared to defend themselves and their supplies from those that survive the initial disaster that did not prepare.
However, I agree in principle that one should be prepared for disaster and only the prepared (and the lucky) will survive long term.
I was a 91A medic in the US Army, and I was a Boy Scout. I have food, water, shelted, weapons and ammo, commo, etc. prepared for several different senarios: 3-day, 1 month, and indefinite future.
If the worst DOES happen, you can contact me voice at 14.15 MHz. Like minded people that have prepared will be welcome in my neighborhood.
Arghhh! . . . Never mind, sez Emily Latella. The table gave the probability as 2.2e-02, and by this they meant 2.2 x 10-2. But I took "e" to mean the number "e," as in natural logarithms. :-(
I remember reading about that as a form of deep space propulsion in addition to a Bussard ramjet.
So are we essentially racing this asteroid around the sun? And it's slowly coming into our path?
It's the way people who deal with astronomically high numbers stay sane.
I think you were the only one who got it. :)
2006 pops up only one sentence, "the only surefire way to stop Hillary is in New York".
So are we essentially racing this asteroid around the sun?
Lookie here,
http://neo.jpl.nasa.gov/cgi-bin/db?name=2004+MN4
They have an interactive tool, you can zoom, rotate animate and change time step. Basically it's in an oval orbit that extends from just outside venus to just outside earths orbit. It's orbit is slightly inclined to the earth's but crosses earth's orbit around the point in the earth's orbit where earth is on April 13 every year. Most years he's not there on April 13, so it's no big deal. In 2029 we both get there around the same time. Could be a big deal.
Nope. That's not that big, and it also depends on the angle of impact. a 400meter asteroid hitting mid ocean would cause a title wave but other than that the affects would be short lived. Hit on land it would throw a lot of stuff into the atmosphere, but probably not as much as Mt. St. Helens, and certainly not as much as Krakatoa.
True, and the death toll was nill as far as anyone can tell. One wonders if a 400 meter asteriod would break up or land intact.
This site has some interesting info - http://users.tpg.com.au/users/tps-seti/spacegd7.html
and there is information on this site about the tsunami effect caused by asteriods.
The web site mention above says that an impact from a 2km diameter stony asteroid is thought to be at the threshold of a global catastrophe and the "damage" would go well beyond the area of direct devastation. It has been estimated that one quarter of the world's population could die from starvation and other indirect effects due to a 2 km asteroid impact.
Yup, that pretty well agrees with what I learned on this subject. The 400meter object is far from a planet killer, and the better prediction of impact area (if it does in fact hit) the better chances we have of avoiding a high death toll, as I mentioned in my #111 above.
This web site - http://www.space.com/scienceastronomy/astronomy/asteroid_paine_september.html
is easier for a non-scientist like me to understand compared with my earlier link. It gives the example of a 500 yard (bigger but in roughly the same ball park) asteroid producing a runup wave height of up to 120 feet at 1000 miles from impact. The actual wave height depends on the topography of the shore.
In 1815 a volcano on the Indonesian island of Tambora exploded and produced a crater similar in size to that from a 500-yard asteroid. About 20 cubic miles of ejecta was released (for comparison, the Mount St. Helens explosion in 1980 released about a quarter of a cubic mile of ejecta).
In the case of Tambora, it has been estimated that 10,000 people died directly from the explosion and 80,000 more died in the region from indirect effects, such as starvation. In addition, the ash is thought to have caused the "year without a summer" in 1816, when there were widespread crop failures across North America. The final death toll was probably in the hundreds of thousands. A similar event today might kill millions.
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