Starship Asterisk*

Ok this one seems quite a bit more plausible than the doomsday, fear-mongerer Eric Julien about SW-3 and it hitting Earth on May 25, 2006

You can find this article in, coincidentally, May's issue of Astronomy (the magazine). If you're not familiar with it, it's reputable and is found on almost any store's newsstand in North America (and possibly other countries??)

Asteroid 99942 Apophis will be passing approximately 22,000 miles from Earth on April 13 of 2029. What sets it apart from most other Near Earth Objects (NEOs) is that further observations almost eliminate any chance of them impacting Earth. With Apophis on the other hand, every subsequent observation of the asteroid increased the probability that it would strike.

On December 18, 2004, and a few days following, several observations...

enabled the risk-assessment software at NASA's NEO Program Office and at the University of Pisa in Italy to compute the odds of an impact. There was a 1-in-300 chance the asteroid would strike Earth April 13, 2029. More observations filtered in. On December 24, the chance of an impact jumped to 1 in 60. Then, on Christmas Day, it rose to 1 in 42. It reached a maximum of 1 in 37 December 27. This trend is unusual. For nearly all NEOs, the odds of an impact decrease as more observations contribute to the analysis.

If there was a bright spot in the events of that December, it involved estimates of the asteroid's size, which started out at 500m (550 yards). Size estimates decreased as the impact probability rose. Astronomers now think Apophis measures about 320m (350 yards) across. Despite it's smaller size, a collision would still pack a walop: The asteroid has the striking power of 870 megatons of TNT.

To put this in perspective, it's about 2 to 4 times the energy released when Krakatoa, a volcanoe in Indonesia, blew up in 1883. The blast and the after effects killed more than 36,000 people, mostly by tsunamis, which swept away 165 coastal villages. It's also 15 times more powerful than a nuke set off by the Soviet Union in 1961 with the force of 58 megatons of TNT, the most powerful ever detonated.

On the same day the announcement was made of an impact risk of 1 in 37, a search for pre-discovery images of the asteroid brought in more data for analysis. New calculations based on the expanded set of observations now spanning 287 days, dropped Apophis' strike risk to below 1 in 10,000.

But Apophis will still miss Earth by a mere 64,000 km (40,000 miles). Something like this only happens roughly every 1300 years or so.

Then at the end of January of 2005, the Arecibo radio telescope was trained on the asteroid and refined it's orbit to within 34,400 km (22,000 miles). But it's not over yet, they have refined the orbit to eliminate all but one resonance keyhole. They explain that a resonance keyhole is a small region of space that if the asteroid were to pass through it, its course would be altered due to Earth's gravity.... and this particular keyhole would lead to a collision in April of 2036. Although the odds are still slim (about 1 in 5000) Apophis' orbit is so close to this keyhole that scientists can't rule out the possibility at this time.

Another interesting fact about Apophis...
There is a scale called the Torino scale, numbered from 0 to 10 where 0 = no threat and 10 = catastrophe. Most NEO's so far have reached a level of 1 before dropping down to 0 and only a few have reached 2. Apophis achieved a rank of 4 - defined as a close encounter that merits attention by astronomers.

No other NEO has ever posed this great a threat to Earth.

I hope you found this interesting

Hello All

Astronomers Gear Up for Historic Asteroid Pass in 2029
http://www.space.com/scienceastronomy/0 ... ophis.html

During the early morning hours of April 13, 2029, observers in Asia and North Africa will have a chance to witness a rare celestial event as an asteroid, 99942 Apophis, passes within 20,000 miles of Earth.

scientists now predict there is about a 1-in-10,000 chance that the asteroid will hit Earth in 2036, on yet another of its trips around the Sun on a course that crosses the orbit of Earth

This is close

yup, i wrote about this a while back but in the Asterisk Cafe, here's the link

http://asterisk.apod.com/vie ... ht=apophis

Hello Galactic

Sorry that I missed your post last time.

I read it

No worries mate .... I hope in that year I'm in either Asia or North Africa to witness this!!!

Hi Harry,

Did you see the article today about a permanent Moon Base by 2024 begining?

Sounds like somebody wants to be prepared in case Apophis hits the Earth, so they have a place to hang till the 'impact winter' is over and then return to Earth and mop up !

Might be a long winter !!!

Cheers

If Apophis does come within 20,000 mi from Earth; I would presume that the gravitational pull of the Earth would probably cause the orbit of the asteroid to be changed somewhat.
Orin

Hi Orin,

The 20,000 miles close encounter include the effect of earth gravity. But i think that what is not calculable is the unknown gravity influence of unknown asteroid. A tiny change of direction of an asteroid made by a small gravity effect (Another asteroid) may, at long term ( A few centuries or many thousands years later. ), plot a course for an impact (Or not) but in short time this possible effect increase the incertitude of knowing where and when the asteroid will pass over the earth (A few hours or minutes to a few years.). Those effect are so tiny that it is possible to know precisely enough when and where if its a few years from encounter. Time will tell.

During the early morning hours of April 13, 2029, observers in Asia and North Africa will have a chance to witness a rare celestial event as an asteroid, 99942 Apophis, passes within 20,000 miles of Earth.

If it is known what side of earth will be facing the event on that particular date, then what side will be facing it on the following, potentially impacting pass?

If your talking about the next day, then yes we can know that precisely enough.
But on a long run, it's different. The path calculated is an estimate of an event far away in the futur. So if the calculation say, that it will miss or not, that might be false because of many possible encounter of that asteroid with other unknown one. (gravity changing course) wich mean that the calculated course didnt count that futur unknown encounter. What im saying here is what i read somewhere in a book a long time ago. But it make sense and its logic. Being precise on a long run is hard. If the halley comet do not encounter any mass in his travel in the deep space before returning near the sun then the calculation of his orbit will be correct. If it did encounter then it might change a lot or just a tiny bit it's orbir. It's the unknown.

Hello All

Hello kovil

Hello Orin, yes you are right, the earth's gravity will change the orbit and in so doing, they may have to call Mr Die Hard and his drilling team to go where no man has gone before.

ya, depending on where it passes by in 2029 we'll have much more specific data as to where it will be, so we'll have 7 years to prepare for a closer flyby or possible impact in 2036 depending on that data. And i believe BMAONE23 meant what side will the Earth be facing in 2036, which.... i wouldn't know

http://sohowww.nascom.nasa.gov/data/realtime/mpeg/
Watch the SOHO MPEG LASCO-C3 files from September through December 2009. Apophis should be passing behind the Sun from the Earths perspectiveand should be visible in SOHO's field of view.
http://ssd.jpl.nasa.gov/sbdb.cgi?sstr=2004%20MN4;orb=1

BMAone23

My son thanks you for the link.

Doing a school project.

Any time

G'day Bmaone23

The time is 7.21am Sunday,,,,,,,,,,,,,,,thank you,,,,,,,,,,smile

Asteroid Apophis 2004MN4 will come within 29000 km/ 18000 mi of striking the Earth on April 13th, 2029 this asteroid will come inside the orbits of most of are major satellites. This asteriod is the size of 3 football fields and if it hits a 400km gravitational keyhole as it sling shots aroung us then it will return in 2036 for impact. check out the videos on my site.Astronomy and Pictures, See the damage that can happen.

The SOHO Observatory MPEG Site look at the LASCO-C3 movie (blue) at the bottom right. During the months of late October thru Mid November 2009, Apophis will be opposite the sun from us and should appear in the C3 MPG file during that time. It will be a very small pixel traveling toward the left against the background of stars (although it will look like it is traveling right compared to the sun.)

BMAONE23 wrote:The SOHO Observatory MPEG Site look at the LASCO-C3 movie (blue) at the bottom right. During the months of late October thru Mid November 2009, Apophis will be opposite the sun from us and should appear in the C3 MPG file during that time. It will be a very small pixel traveling toward the left against the background of stars (although it will look like it is traveling right compared to the sun.)

Thank you. I keep a eye on it.

Should be very similar to what is visible right now with Mars traveling against the background towards the left but traveling right towards the sun.

interstellaryeller wrote:...if it hits a 400km gravitational keyhole as it sling shots aroung us then it will return in 2036 for impact.

You're off by a factor of one thousand, roughly. The gravitational keyhole is only ~600m across.

Unfortunately the SOHO MPEGS aren't current, they end on 10-24. I was hoping to see Apophis as it passed behind the sun (from our perspective) and crosses the Earths orbital plane. It should be visible in the SOHO image frame right about now. It could be the elongated bright feature in the still images at 9:15 but without the moving images it would be hard to discern its orbital movement
http://sohodata.nascom.nasa.gov/cgi-bin ... etector=C3

Roscosmos head Anatoly Perminov has revealed a plan to set up closed meeting somewhere in 2010 to discuss Apophis deflection operation.

(source)

This guy is always fun.
Neil deGrasse Tyson - Attack of the Killer Asteroid Apophis