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.
So what? Does that mean everybody is going to commit suicide and rob banks, rape and pillage?
13000 died this weekend in tsunamis. With warning of even a few hours few would have died. With warning of a few weeks no one would have died.
With warning of a few weeks we could mount massive computer simulations to determine a fairly prcise point of impact and do mass evacuations.
People can handle this stuff if they are simply told about it. The idea that we need government to hide the truth from us is frankly rather insulting to me, but if that's what gets you thru the night, you're welcome to it.
Impact probability has been revised upward per JPL/NASA, now 2.7% (1:37 roughly). As I mentioned in other threads, much of the margin of error is mecessary due to suspect calibrations and missing parameters for the orbital models. Once we get the data problem sorted out, the orbital elements should solidify very nicely.
Nuclear won't do it either. When Nukes go off on earth, its the shock wave and heat that do the most damage. Out in space even hitting one side of a rather large asteroid may do a little melting but since a nuke in space would be mostly heat and light, there is no kinetic shock energy to break up the asteroid or to make it change course. Even if you could land on the asteroid to bury it or drill deep to place it, there is no air in the rock of said asteroid, just solid matter, so there is no guarantee that a nuke would do more than melt the rock on the inside....though melting the rock to vaporisation from the inside out may cause it to explode from the various gasses and pressures produced. This would create showers of meteors that would be very hard to predict in terms of impact. Smaller asteroids a mile or less may very well be destroyed easily this way but very large ones such as greater than one mile to hundreds of miles would need more more long range work.
Simply throwing missiles at them won't destroy them.
Wait....wait... We're picking up something.... the transmission reads: "beep beep boop beep boop..."
I read that book. It was a good one.
Ping me in 2028.
Personally, if it has to hit I hope it hits either Tehran or Beijing.
IMO: Results will be the same for all of us, Asia or North America.
Let's all build those 1962 bomb shelters now......
Hope the Chiefs win the Super Bowl by then. If 2030 is going to be their year I will be TICKED OFF!
When I lived in Alabama (late 1970s), the average State Trooper drove a Grand Torino with a full race cam. No sense in a citizen even trying to outrun those bad boys.
"Luicifer's Hammer"
One of my favorite books.
Sounds very interesting, do you have a link for the thread you can post?
A few 1-ton objects guided to kinetic impact at orbital velocity on its way in, would likely break it up into a manageable cluster of rocks.
You don't need to obliterate it, just break it up enough that the pieces mostly burn up in the atmosphere
But it's not uncommon for meteorites to hit us with a relative speed of 150 km/sec or more. The Arizona crater was formed by a sliver approximately the size of a cruise ship. This new object is traveling in an orbit that is similar to the Earth's own orbit. This means a low relative speed, and also that it will be relatively easy for Bruce Willis to soft-land on it and drill holes.
> Out in space even hitting one side of a rather large asteroid may do a little melting but since a nuke in space would be mostly heat and light, there is no kinetic shock energy to break up the asteroid or to make it change course.
You are incorrect. One thing you may want to look up: "Project Orion." It is something I have spent years researching, even to the point of getting quoted and some of my writing referenced in George Dyson's book of the same name. In short, Orion was the Coolest Propulsion System Ever: toss a nuke out the back of your spaceship, set it off, ride the blast, repeat. One 0.5 kiloton yield nuke every second or so would provide up to 8,000 to 16,000 *tons* of thrust.
In short, there are two ways to use a nuke to provide thrust:
1) Shock. Yes, there is no air in space. But the bomb itself is not converted to pure energy; it it for the most part converted to megadegree plasma. Orion pulse unit desings would be marvelous items for asteroid nudging. You build a bomb that has propellant on one side of it... propellant being something like water or polyethylene. (Orion used tungsten. even though the very high molecular weight of tungsten reduced the specific impulse available, the extreme density of the stuff made packaging *far* easier.)
When the bomb goes off, the radiation in the form of X-rays and neutrons can be modestly focussed into the propellant. As a result, the propellant is raised to several million degrees in microseconds, and explodes. Proper shaping of the propellant will give you a shaped charge effect... the propellant will turn into a jet of plasma moving at a good fraction of the speed of light. This jet, several *hundred* or *thousand* pounds, moving at maybe 5% lightspeed, will pack a massive wallop. Stand you bomb off from the asteroid however many miles required so that the jet spreads out as much as it can; this will spread the impulse over the largest possible surface and help reduce the chances of breaking the asteroid apart.
2) Ablation: build your nuke to emit as much energy as possible int the form of a narrow beam, again likely using shaped-charge principles. Put you bomb reasonable close to the surface and set it off. The result will be that one specific spot on the asteroid willbe converted to plasma, much as int the first case. This plasma explodes out of the asteroid, and serves as a brief but powerful rocket engine.
Total impulse per bomb can be far higher with 2) than with 1). However, by localizing the blombs effects on the asteroid, you stand a greater chances of simply shattering the asteroid. This is probably not what you want to do.
And then there's always the "Medusa* approach to moving an asteroid with nukes. But that's more complex.
"and Planet Earth is a sitting duck!"
Exactly. Time to make this baby more maneuverable!
Well you just proved my point...nukes alone wouldn't do it. Nukes designed as you suggest would be rechanneled into various forms of kinetic or coherent beamed energy that would do the job!
Huh? I never suggested that. Those are your words.
13000 died this weekend in tsunamis.
Yeah, this too would be small potatoes compared to a 400 meter asteroid impacting earth. Even with warning. The events you mentioned are not even in the same ball park. An asteroid of that size would be off the scale. Trust me.
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