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Apophis asteroid, close encounter with Earth?
http://upload.wikimedia.org/wikipedia/commons/e/e7/2004MN4_Sormano.gif
Nick, are you prepared?
The most probable scenarios today are not about Comets (possible Earth life killer events) but about somewhat less dangerous stellar objects: Asteroids. I believe scientists today are able to predict better observations and calculations of trajectory paths, for both Comets and Asteroids.
Neil DeGrasse Tyson, one of the most important astrophysist today, director of the Hayden Planetarium, American Museum of Natural History and writer of the book "Death by a Black Hole and Other Cosmic Quandries" recently explained about the asteroid called Apophis (known as 99942 Apophis) which is scheduled to arrive near Earth vicinity on the 13th of April, 2029 (20 years from now).
This asteroid was discovered by astronomers from NASA Spaceguard Survey Working Group in December 2004. Since then, they have calculated the asteroid´s orbit and found its precise trajectory towards Earth. It turned out that Apophis, an asteroid more than 300 meters long, will come so close to Earth that it will deep below our own communication satellites. A near miss!
It will become the largest cosmic object to come by Earth tracked by the human kind in the era of observing the cosmos with modern telescope technology. Still, the orbit where the asteroid is spected to pass is uncertain enough (because calculations are not that exact) that there is a window of 600 hundred miles in diameter, a keyhole, where the asteroid will cross.
If the asteroid pass exactly thru the middle of that keyhole, it will return on the 13th of April 2036 (7 years later, after another lengthy orbit) triggering a collision with Earth and this time it will hit in a precise point in the middle of the Pacific Ocean, 500 kilometers west from the coast of Santa Monica, California.
If the asteroid passes thru other places in that keyhole, the impact zone will shift from that center point either west or east, meaning it will impact further into the Pacific Ocean or closer to the continental US.
Assuming it will impact 500 kilometers from Santa Monica, the asteroid will plunge down into the ocean sea floor 3 miles deep where it will explode, cavitating the Pacific in a hole 3 miles wide, sending a huge 50 feet high tsunami wave from that point outwards. The receding wall of ocean water in the hole will collapse in itself sloshing fiercely and producing a column of water that will rise up into the upper atmosphere falling down into the ocean and cavitating the ocean again, all in the span of 50 seconds, creating a second tsunami wave.
Next time Apophis will pass close to the Earth will be in the year 2013, when astronomers spect to have a much clear knowledge of the asteroid's orbit in time to initiate a deflection mission. The 16 years available between 2013 and 2029 are sufficient to recognize and respond to any hazard that still exists after that time. Still, if Apophis is on an impact trajectory, the radar observations will not be able to refine the impact probability to more than 20%. Astronomers will not be able to tell better than 1 chance in 5 whether the impact would really occur or not.
The possibility of the Apophis asteroid was kept at Level 1 on the Torino impact hazard scale until August 2006. As of October 2009, the impact probability for the April 13, 2036 encounter, is now being calculated as 1 in 250.000
What ever the results, the implications are huge for that region of the planet if Apophis hits the Earth 27 years from now. You must watch Neil DeGrasse Tyson video (here in two parts), a must see, because is very illustrative on the level of astronomical predictions and technicality astronomers have accomplished and it is unique because the humorous twist he puts into his speech.
Neil DeGrasse Tyson - Death by Giant Meteor.
http://www.youtube.com/watch?v=xaW4Ol3_M1o
Neil DeGrasse Tyson - How to Deflect a Killer Asteroid.
http://www.youtube.com/watch?v=1-ReuLZ2quc
Source(s):
http://www.space.com/news/051103_asteroid_apophis.html
http://en.wikipedia.org/wiki/99942_Apophis
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http://www.coverbrowser.com/image/bestselling-sci-fi-fantasy-2006/206-1.jpg
There have been several scientific advances which have resulted in better observations and, therefore, calculations of trajectories. Case in point is a 1999 paper: http://adsabs.harvard.edu/abs/1999AdSpR..23..777O
Dealing with an imminent strike is anyone's guess. I can't see any way of deflecting a trajectory enough in advance of an imminent strike and the attempts at deflection might simply create a sort of break-up - several smaller earth-bound objects still traveling on a collision trajectory.
Chances are that if there were a strike, events would play out in similar fashion to those written about by Niven and Pournelle. Earthquakes and volcanic eruptions because of disruptions along fault lines, tsunamis from strikes in the oceans and seas, an EMP from the disruption to the core would probably wipe out most electronic devices, chaos, famine, and an early ice age onset would certainly make survival challenging. I'm not sure I could cite a good source for this sort of supposition except from Science Fiction sources.
Source(s):
http://adsabs.harvard.edu/abs/1999AdSpR..23..777O
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Whether or not the authorities will release this information to the general public is uncertain, as it would likely cause wide-spread panic and destructive behavior. It is doubtful however that the information would stay secret very long since any discovery would be known to many people, and it would be hard to enforce secrecy when the world would literally be coming to an end.
Current technology would not likely be up to the task of diverting such an object enough to miss the Earth. One would have to impose a huge delta-V and/or impose it at a very far remove from the Earth. The farther from Earth, the more difficult it becomes to exert a high delta-V. Thus, where it would do the most good, we'd have the hardest time doing anything significant.
To cap off this grim discussion, it has been calculated that a dinosaur-killer class object has hit the Earth on average every 50 million years or so. The last one known was 65 million years ago, so we appear to be over-due. Keep in mind that when dealing with astronomical objects, the scales, both in space and in time are very different from the scales that humans deal with day-to-day. Thus, saying we're overdue, even if such events were not statistically independent, would mean such an object might hit the Earth any millenium now.
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Comets are similar in speed to planets. If they were much faster they would escape solar orbit and if they were much slower they would have fallen into the Sun. So on an astronomical scale they are in the same speed range. The distances are also comparable to planetary motion (as opposed to the far more distant stars or the far closer moon).
The Earth, of course, orbits the Sun once per year. Haley's Comet orbits the Sun every 76 years. Other comets vary but we are talking about years not hours etc.
As comets develop tails and become bright as they reach the inner solar system they can be seen from much further away than mere asteroids. While a small asteroid may be detected only days away from possible collision with Earth, a comet would be detected months or years in advance. A comet large enough to actually destroy earth would be detected many decades in advance. That is not to say it would be predicted to actually hit Earth years in advance, but rather that it would be predicted to come close.
However, if you want to worry, scientists can help you decide what to worry about, astronomically speaking, and have begun meeting to discuss such things:
http://impact.arc.nasa.gov/news_detail.cfm?ID=181
Note that most articles on this subject are more interested in whether we would have enough time or ability to do anything about the approaching comet than whether we would see it coming at all. Prevention or mitigation of an impact is a different question entirely.
Source(s):
http://impact.arc.nasa.gov/intro_faq.cfm
http://www.sandia.gov/video/CometSim.htm
http://www.boulder.swri.edu/clark/neowp.html
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Answered Question
M$3.10
October 08, 2009 11:24 AM
A comet is coming to destroy Earth?
What would happen, I recall reading in a quite serious book that we would never actually realize it because comets travel too fast and before we could detect its exact path towards us the comet would have already destroyed the planet.
What's the truth, Armageddon style or would there be no chance of survival? Serious sources and data please :)
What's the truth, Armageddon style or would there be no chance of survival? Serious sources and data please :)
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| October 08, 2009 03:58 PM |
Nick, are you prepared?
The most probable scenarios today are not about Comets (possible Earth life killer events) but about somewhat less dangerous stellar objects: Asteroids. I believe scientists today are able to predict better observations and calculations of trajectory paths, for both Comets and Asteroids.
Neil DeGrasse Tyson, one of the most important astrophysist today, director of the Hayden Planetarium, American Museum of Natural History and writer of the book "Death by a Black Hole and Other Cosmic Quandries" recently explained about the asteroid called Apophis (known as 99942 Apophis) which is scheduled to arrive near Earth vicinity on the 13th of April, 2029 (20 years from now).
This asteroid was discovered by astronomers from NASA Spaceguard Survey Working Group in December 2004. Since then, they have calculated the asteroid´s orbit and found its precise trajectory towards Earth. It turned out that Apophis, an asteroid more than 300 meters long, will come so close to Earth that it will deep below our own communication satellites. A near miss!
It will become the largest cosmic object to come by Earth tracked by the human kind in the era of observing the cosmos with modern telescope technology. Still, the orbit where the asteroid is spected to pass is uncertain enough (because calculations are not that exact) that there is a window of 600 hundred miles in diameter, a keyhole, where the asteroid will cross.
If the asteroid pass exactly thru the middle of that keyhole, it will return on the 13th of April 2036 (7 years later, after another lengthy orbit) triggering a collision with Earth and this time it will hit in a precise point in the middle of the Pacific Ocean, 500 kilometers west from the coast of Santa Monica, California.
If the asteroid passes thru other places in that keyhole, the impact zone will shift from that center point either west or east, meaning it will impact further into the Pacific Ocean or closer to the continental US.
Assuming it will impact 500 kilometers from Santa Monica, the asteroid will plunge down into the ocean sea floor 3 miles deep where it will explode, cavitating the Pacific in a hole 3 miles wide, sending a huge 50 feet high tsunami wave from that point outwards. The receding wall of ocean water in the hole will collapse in itself sloshing fiercely and producing a column of water that will rise up into the upper atmosphere falling down into the ocean and cavitating the ocean again, all in the span of 50 seconds, creating a second tsunami wave.
Next time Apophis will pass close to the Earth will be in the year 2013, when astronomers spect to have a much clear knowledge of the asteroid's orbit in time to initiate a deflection mission. The 16 years available between 2013 and 2029 are sufficient to recognize and respond to any hazard that still exists after that time. Still, if Apophis is on an impact trajectory, the radar observations will not be able to refine the impact probability to more than 20%. Astronomers will not be able to tell better than 1 chance in 5 whether the impact would really occur or not.
The possibility of the Apophis asteroid was kept at Level 1 on the Torino impact hazard scale until August 2006. As of October 2009, the impact probability for the April 13, 2036 encounter, is now being calculated as 1 in 250.000
What ever the results, the implications are huge for that region of the planet if Apophis hits the Earth 27 years from now. You must watch Neil DeGrasse Tyson video (here in two parts), a must see, because is very illustrative on the level of astronomical predictions and technicality astronomers have accomplished and it is unique because the humorous twist he puts into his speech.
Neil DeGrasse Tyson - Death by Giant Meteor.
http://www.youtube.com/watch?v=xaW4Ol3_M1o
Neil DeGrasse Tyson - How to Deflect a Killer Asteroid.
http://www.youtube.com/watch?v=1-ReuLZ2quc
Source(s):
http://www.space.com/news/051103_asteroid_apophis.html
http://en.wikipedia.org/wiki/99942_Apophis
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Other Answers (5)
October 08, 2009 12:08 PM
It sounds as though the book you might have read was Lucifer's Hammer, by Larry Niven and Jerry Pournelle. They published the book in 1977 and based on the existing science of the day (pre-Hubble and certainly pre-working Hubble), scientists likely could not have calculated the trajectory accurately. Although the book was science fiction, it had a solid, well-researched scientific basis. There have been several scientific advances which have resulted in better observations and, therefore, calculations of trajectories. Case in point is a 1999 paper: http://adsabs.harvard.edu/abs/1999AdSpR..23..777O
Dealing with an imminent strike is anyone's guess. I can't see any way of deflecting a trajectory enough in advance of an imminent strike and the attempts at deflection might simply create a sort of break-up - several smaller earth-bound objects still traveling on a collision trajectory.
Chances are that if there were a strike, events would play out in similar fashion to those written about by Niven and Pournelle. Earthquakes and volcanic eruptions because of disruptions along fault lines, tsunamis from strikes in the oceans and seas, an EMP from the disruption to the core would probably wipe out most electronic devices, chaos, famine, and an early ice age onset would certainly make survival challenging. I'm not sure I could cite a good source for this sort of supposition except from Science Fiction sources.
Source(s):
http://adsabs.harvard.edu/abs/1999AdSpR..23..777O
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Helpful: lilyloretta, safiqulislam, nickunderscore, shadowbear
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October 08, 2009 03:45 PM
I read it in another book, something brief history of the world, it was pretty recent. You mentioned some advancement in better observation and calculation of trajectory paths, but did you find any information wether researchers know enough to actually predict an impact?
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October 08, 2009 04:24 PM
At this point, yes, they would accurately be able to predict an impact, as mentioned by @opher. The problem is that we do not, at this point in time, have any technology which would change the trajectory of the comet at a distance far enough out to change the outcome. It's not that we wouldn't see it coming... it's that we couldn't do anything effective about it.
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October 08, 2009 12:46 PM
Today there are major observatories busy scanning the skies, locating and tracking any large objects on near-collision courses with the Earth. It is unlikely in the extreme that any object large enough to cause mass destruction could hit the Earth without these observatories seeing it in advance. The larger the object the further advance notice there will be. Whether or not the authorities will release this information to the general public is uncertain, as it would likely cause wide-spread panic and destructive behavior. It is doubtful however that the information would stay secret very long since any discovery would be known to many people, and it would be hard to enforce secrecy when the world would literally be coming to an end.
Current technology would not likely be up to the task of diverting such an object enough to miss the Earth. One would have to impose a huge delta-V and/or impose it at a very far remove from the Earth. The farther from Earth, the more difficult it becomes to exert a high delta-V. Thus, where it would do the most good, we'd have the hardest time doing anything significant.
To cap off this grim discussion, it has been calculated that a dinosaur-killer class object has hit the Earth on average every 50 million years or so. The last one known was 65 million years ago, so we appear to be over-due. Keep in mind that when dealing with astronomical objects, the scales, both in space and in time are very different from the scales that humans deal with day-to-day. Thus, saying we're overdue, even if such events were not statistically independent, would mean such an object might hit the Earth any millenium now.
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October 08, 2009 01:15 PM
Please remember to give your sources, as this is a great answer otherwise!
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October 08, 2009 02:59 PM
"There is no question that an asteroid has Earths name on it, astronomers agree. But where the rock is and when that impact is going to occur is unknown, said David Morrison of the NASA Astrobiology Institute at the space agencys Ames Research Center at Moffett Field, California" (http://www.space.com/scienceastronomy/planetary_defense_040225.html).
"Impacts by Earth-approaching asteroids and comets pose a significant
hazard to life and property. Although the annual probability of the Earth
being struck by a large asteroid or comet is extremely small, the
consequences of such a collision are so catastrophic that it is prudent to
assess the nature of the threat and prepare to deal with it. The first step in
any program for the prevention or mitigation of impact catastrophes
must involve a comprehensive search for Earth-crossing asteroids and
comets and a detailed analysis of their orbits.
"Current technology permits us to discover and track nearly all asteroids
or short-period comets larger than 1 km diameter that are potential
Earth-impactors… What is required … is a systematic survey that
effectively monitors a large volume of space around our planet and
detects these objects as their orbits repeatedly carry them through this
volume of space… The international survey program described in this
report can be thought of as a modest investment to insure our planet
against the ultimate catastrophe."
NASA Spaceguard Survey Working Group, January 1992
The above statements also appeared in http://impact.arc.nasa.gov/downloads/impactsdmfh101200.pdf.
There is a NASA site at http:// impact.arc.nasa.gov providing much more information.
Report
"Impacts by Earth-approaching asteroids and comets pose a significant
hazard to life and property. Although the annual probability of the Earth
being struck by a large asteroid or comet is extremely small, the
consequences of such a collision are so catastrophic that it is prudent to
assess the nature of the threat and prepare to deal with it. The first step in
any program for the prevention or mitigation of impact catastrophes
must involve a comprehensive search for Earth-crossing asteroids and
comets and a detailed analysis of their orbits.
"Current technology permits us to discover and track nearly all asteroids
or short-period comets larger than 1 km diameter that are potential
Earth-impactors… What is required … is a systematic survey that
effectively monitors a large volume of space around our planet and
detects these objects as their orbits repeatedly carry them through this
volume of space… The international survey program described in this
report can be thought of as a modest investment to insure our planet
against the ultimate catastrophe."
NASA Spaceguard Survey Working Group, January 1992
The above statements also appeared in http://impact.arc.nasa.gov/downloads/impactsdmfh101200.pdf.
There is a NASA site at http:// impact.arc.nasa.gov providing much more information.
October 08, 2009 03:49 PM
Thank you for giving the source :) because it states exactly what I wanted to hear: "Current technology permits us to discover and track nearly all asteroids
or short-period comets larger than 1 km diameter that are potential
Earth-impactors"
I guess if NASA is correct then the statement in the book I read was wrong, because it said there was no way of predicting Earth bound comets.
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or short-period comets larger than 1 km diameter that are potential
Earth-impactors"
I guess if NASA is correct then the statement in the book I read was wrong, because it said there was no way of predicting Earth bound comets.
October 08, 2009 05:19 PM
Oh....awesome! So I nominated you in ATOD. Here is the link to view my nomination. answer-of-the-day-contest-for-october-9-th
Good job ma friend
http://www.flickr.com/photos/33749589@40N07/3917686970
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Good job ma friend
October 09, 2009 04:27 PM
Congratulations! Your answer won second place in our Answer of the Day contest! You win $3.00 and are now the proud owner of the Mahalo Tiki Torch!
http://www.flickr.com/photos/33749589@N07/3916894609/
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October 08, 2009 03:54 PM
No, comets do not travel all that fast and this would not have been true in recent times. The idea is probably based on sensationalizing some facts out of context, in particular knowing for certain whether a comet would hit or be a near miss. We would certainly see the comet heading for Earth long in advance. Although we might not know if it would really hit we would not be taken by surprise. Comets are similar in speed to planets. If they were much faster they would escape solar orbit and if they were much slower they would have fallen into the Sun. So on an astronomical scale they are in the same speed range. The distances are also comparable to planetary motion (as opposed to the far more distant stars or the far closer moon).
The Earth, of course, orbits the Sun once per year. Haley's Comet orbits the Sun every 76 years. Other comets vary but we are talking about years not hours etc.
As comets develop tails and become bright as they reach the inner solar system they can be seen from much further away than mere asteroids. While a small asteroid may be detected only days away from possible collision with Earth, a comet would be detected months or years in advance. A comet large enough to actually destroy earth would be detected many decades in advance. That is not to say it would be predicted to actually hit Earth years in advance, but rather that it would be predicted to come close.
However, if you want to worry, scientists can help you decide what to worry about, astronomically speaking, and have begun meeting to discuss such things:
http://impact.arc.nasa.gov/news_detail.cfm?ID=181
Note that most articles on this subject are more interested in whether we would have enough time or ability to do anything about the approaching comet than whether we would see it coming at all. Prevention or mitigation of an impact is a different question entirely.
Source(s):
http://impact.arc.nasa.gov/intro_faq.cfm
http://www.sandia.gov/video/CometSim.htm
http://www.boulder.swri.edu/clark/neowp.html
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October 08, 2009 09:16 PM
I think people are tending to confuse comets with asteroids. A cometary impact would make a mess, but it wouldn't be nearly as catacalysmic as an asteroid impact.
After things settled down after a comet impact, all we'd have is slightly deeper oceans, which might not be such a bad thing, given how the oceans have been gradually drying off for the last 3.5 billion years.
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After things settled down after a comet impact, all we'd have is slightly deeper oceans, which might not be such a bad thing, given how the oceans have been gradually drying off for the last 3.5 billion years.
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Anyway great answer and thanks for the videos!
So, if a renown astronomer is saying a rock could probably hit us in 27 years... it is not too bad to listen what he may have to say. Besides, the probability of Apophis impact is getting scarce with every year that passes.
What is really important here is the fact that astronomers are indeed in a position to discover, identify, track and predict a cosmic object years in advance for a probable impact on Earth. The implementation of contingency plans for such scenarios are more probable today than they were a few years back.
I'm sure this is for the right day ( I'm in a different time zone, but this is such a good answer I'm nominating it :)