Could Comet C/2013 A1 impact Mars in 2014?

[statickid]

The gambler's fallacy is that if there is a string of events of one result then the next event must be the reverse "to even things out". That is not the case if the events really are independent.
But you can still multiply those chances together to get the chance of them all occurring together assuming they are independent. For example, you can calculate the chance with a fair dice of getting sixteen consecutive 7's as 1 chance in 6^16, which is 1 in several trillion. Still even if there were fifteen consecutive rolls of sevens, if the dice is fair the chance of getting some number other than 7 is not increased on the next roll.
In reality though if you did observe that string of dice rolls that had trillions to one odds against it, you'd assume the dice was loaded. That assuming the dice is loaded means you are looking for a physical explanation.


Bob Clark

people explain the fallacy this way, but the real fallacy lies in the failure to see that all outcomes are equally unlikely (or all equally likely).

Any string of dice rolls has trillions to one odds against it. If I told someone they can win my game if they roll the exact sequence of 14 numbers that I write down, their odds of winning will be just as terrible no matter what sequence I write down. This is the idea behind the lotto type games. The people who run it rely on huge amounts more money being spent on tickets than is being payed out to winners.

I would only suspect a loaded dice if after hundreds of dice rolls(large data pile), the dice did not statistically resemble odds of outcomes, meaning there would be more sevens than twos. However at their core, the odds of getting numbers with dice is really based on each dice having a 1 in 6 chance of getting any certain number, the better odds for 7 only come about because of the way we count the pipets. If we made the different 7's that can be rolled unique, then they would all have the same probability as rolling 2. The rules of the game skew the way we perceive the surfaces of the cubes and also the way that people tend to think about probability. When two different outcomes are considered equal by the game, people forget that rolling 4 and 3 is different than rolling 3 and 4 and both are equal in probability to rolling 1 and 1 or 1 and 6.

When it comes down to it, we simply do not have enough data to know how many close calls and impacts are statistically normal or abnormal. All we know is that compared to our short lives and history, large impacts are what we would consider infrequent and tiny collisions (super tiny) happen on a second by second basis.

 

[RGClark]

I did some research on this comet.
It looks like Venus and Mercury are also in for a close flyby by this comet as it hurtled inwards towards the Sun. Especially the Mercury flyby is a close.

I hadn't heard about that. Do you have a reference?

Bob Clark

 

[Screamer7]

I hadn't heard about that. Do you have a reference?

Bob Clark

I hope this link work....I am not good with pasting links.
Just make sure you updated to the most recent Java update.

http://ssd.jpl.nasa.gov/sbdb.cgi?sstr=C%2F2013%20A1;orb=1;cov=0;log=0;cad=1#orb

But I may be wrong.
It is a 2 dimensional animation.
Maybe the time it passes Venus and Mercury, it is high above their Orbital plane.

 

[TMac3000]

What changes would we expect at the surface if it did hit?

Twenty billion megatons--YIKES:blink:
Well, there goes any hope of finding life on Mars

Could the force of such an impact on a terrestrial planet cause a noticable change in its orbit or rotation?

 

[garyw]

I hope this link work....I am not good with pasting links.
Just make sure you updated to the most recent Java update.

http://ssd.jpl.nasa.gov/sbdb.cgi?sstr=C/2013 A1;orb=1;cov=0;log=0;cad=1#orb

But I may be wrong.
It is a 2 dimensional animation.
Maybe the time it passes Venus and Mercury, it is high above their Orbital plane.

Actually, it's three-dimensional.

The comets orbit has a huge inclination of 129 degress. It approaches from underneath the plane of the ecliptic, rushes past Mars then continues to climb away. It is no threat to any other world.

 

[TMac3000]

It is no threat to any other world.

That's good--I'd hate to have to cancel/evacuate Iron Hill

 

[garyw]

One thing I don't understand though is how NASA can say that this comet is from the Oort cloud when it's eccentricity is 1.000468 - surely that puts it at extra-solar with this being it's one and only pass through the solar system?

Also, it's going to be doing 56km/s at Mars which is higher than the 34.1km/s solar escape speed at Mars.

 

[dgatsoulis]

Could the force of such an impact on a terrestrial planet cause a noticable change in its orbit or rotation?

For an Earth impact you'd have no noticable tilt in Earth's axis (< than 5/100ths of a degree) and ~200 milliseconds change in the length of the day.

Source: Impact: Earth!

 

[Kyle]

One thing I don't understand though is how NASA can say that this comet is from the Oort cloud when it's eccentricity is 1.000468 - surely that puts it at extra-solar with this being it's one and only pass through the solar system?

Also, it's going to be doing 56km/s at Mars which is higher than the 34.1km/s solar escape speed at Mars.

I thought it was going 56km/s relative to Mars, seeing as its orbit is retrograde. However, it's eccentricity is certainly unusual, it's not a sun-grazer either like most comets are that end up being ejected from the solar system. If it's an extra-solar object though, my question is - where did it originate from? Another solar system?

 

[TMac3000]

You are ing kidding me
20 billion megatons, and that's all the change it would cause?

Sheesh, I really hate to imagine the event that knocked Uranus over:blink:

 

[garyw]

I thought it was going 56km/s relative to Mars, seeing as its orbit is retrograde.

Ah! Of course, yes it is.

However, it's eccentricity is certainly unusual, it's not a sun-grazer either like most comets are that end up being ejected from the solar system. If it's an extra-solar object though, my question is - where did it originate from? Another solar system?

According to NASA:

Although the current heliocentric orbit is hyperbolic (i.e., eccentricity greater than one), the orbit is elliptic when expressed in the frame of the solar system's barycenter. After more than a million year journey, this comet is arriving from our solar system's distant Oort cloud. It could be complete with the volatile gases that short period comets often lack due to their frequent returns to the sun's neighborhood.

 

[Kyle]

Odds are then, it's from the outer fringes of the Oort Cloud. Still though, you would assume anything with an eccentricity of over 1 would pass significantly closer to the Sun, obviously this is not always the case.

 

[RisingFury]

One thing I don't understand though is how NASA can say that this comet is from the Oort cloud when it's eccentricity is 1.000468 - surely that puts it at extra-solar with this being it's one and only pass through the solar system?

Also, it's going to be doing 56km/s at Mars which is higher than the 34.1km/s solar escape speed at Mars.

Most likely at some point it encountered another Oort cloud object and in effect, got slung into the solar system. The orbits of both objects changed slightly, so instead of a highly eccentric elliptical orbit, it ended up being slung into this one. Objects in the Oort cloud are only loosely bound by gravity, so it doesn't take much...

 

[Screamer7]

Why do I think of Arthur C. Clarke now?
Rama any one?
Just joking.........

 

[MaverickSawyer]

More like "Hammer of God" if you ask me.

 

[garyw]

Most likely at some point it encountered another Oort cloud object and in effect, got slung into the solar system. The orbits of both objects changed slightly, so instead of a highly eccentric elliptical orbit, it ended up being slung into this one. Objects in the Oort cloud are only loosely bound by gravity, so it doesn't take much...

I did some more reading on this and understand it now.

If you look at this coment from the perspective of center of mass of the solar system then it makes sense that the comet will have an eccentricity of just over 1 when referenced against the sun. It means that Oort cloud comets really are only loosely gravitationally bound to the solar system as a whole.

One of those moments when the math explains things better than the text.
http://en.wikipedia.org/wiki/Barycentric_coordinates_(astronomy)

 

[RGClark]

Last weekends meteor over the east coast U.S. was not uncommon according to NASA:

Boulder-Size Asteroid Caused Friday's East Coast Meteor, NASA Says.
By Mike Wall | SPACE.com – Sat, Mar 23, 2013
http://news.yahoo.com/boulder-size-asteroid-caused-fridays-east-coast-meteor-194918370.html

It's estimated about 100 of these meter-sized boulders hit the Earth's atmosphere every year; this one was uncommon in being over a heavily populated area. The fireball over the Bay Area in California in February also was not an uncommonly large one.
However, there may be a characteristic of the east coast meteor that is uncommon, and that is its speed. It's been estimated to have been traveling at perhaps 20 miles per second:

Fiery meteor streaks across Massachusetts’ night sky, seen up and down the East Coast
03/22/2013 11:58 PM

“This is not nearly as big as [Russia’s meteor], not in a long shot,” said Beatty. “There’s a hundred tons of meteorite that hit the Earth’s atmosphere every day. [This] was a large-ish object that may have been the size of about a washing machine, approximately.”
Beatty said the object hit the planet’s atmosphere traveling northwest to southeast at an estimated 20 miles-per-second, but it could have been anywhere from 15 to 50 miles-per-second.
http://www.boston.com/metrodesk/201...-east-coast/jYTaZUlkOhf4tK4UkiS8hO/story.html

East coast residents marvel at Friday night meteor.
Mar 23, 2013 5:32 PM EDT Updated: Mar 23, 2013 6:03 PM EDT

Beatty tells FOX 25 Friday night's meteor was traveling at a speed equivalent to traveling from Boston to New York in about 10 seconds.
http://www.myfoxboston.com/story/21...oast-residents-marvel-at-meteor#ixzz2Og4hz4VH

The distance from Boston to New York is 190 miles. The meteor was seen from Boston to New York. Then fixing the time by video cameras when it appeared over Boston compared to New York would give us an accurate idea of its speed.

IF it really was traveling at 20 miles per second then that would put it in an unusual category since that would put it at the highest speed ever measured for a meteor:

64,000 mph asteroid was fastest on record.
By Brian Dodson
December 30, 2012

At about 14:51 GMT on April 22, 2012, a fireball was seen throughout the western United States, accompanied by a loud booming sound heard over much of California's Sierra Nevada mountains around Lake Tahoe. Scientists have now carried out a thorough analysis of the meteorite and found that it was the fastest meteor ever recorded at 28.6 km/s (64000 mph).
http://www.gizmag.com/sutters-hill-meteor-fastest-kiloton-radar/25552/

Sutter’s Mill Meteor Fastest, Most Diverse Ever.
December 21, 2012 at 04:57 Merryl Azriel
http://www.spacesafetymagazine.com/2012/12/21/sutters-mill-meteor-fastest/

A speed of 20 miles per second for the east coast meteor would put it slightly ahead of the Sutter's Mill meteor which was at 64,000 mph, 17.8 miles per second.

NASA is putting up a list of bolides, fireballs on its NEO web page:

Fireball and Bolide Reports.
http://neo.jpl.nasa.gov/fireballs/

So far it only has the the Chelyabinsk meteor on the list. I think it should also include meteors of size as the east coast and Bay Area meteors, even if ones this size occur a hundred times a year. Such events may still have unusual characteristics that would be uncovered by open dissemination of their physical aspects.

The American Meteor Society has released an analysis of the number of reports made to them by the public of fireballs over the last few years. They conclude that while there has been a definite increase, because of the increasing awareness and the technical tools to report such events, no conclusion can be made about whether this represents a real increase in the number of events:

Fireball Tracking System Analysis.
Analysis of the AMS Citizen Science Based Fireball Tracking System.
http://www.amsmeteors.org/fireballs/fireball-tracking-system-analysis/


Bob Clark

 

[Bloodworth]

Correct me if I'm wrong here, but wouldn't a meteor traveling at 64,000 MPH put that meteor in the "interstellar" category; meaning that it likely came from outside our solar system instead of being a local?

 

[Kyle]

Correct me if I'm wrong here, but wouldn't a meteor traveling at 64,000 MPH put that meteor in the "interstellar" category; meaning that it likely came from outside our solar system instead of being a local?

64,000mph relative to Mars. The orbit is retrograde vs. Mars's prograde orbit.

 

[Bloodworth]

64,000mph relative to Mars. The orbit is retrograde vs. Mars's prograde orbit.

Actually, I was referring to the Sutters Mill meteor. My understanding (and again, I could be wrong) is that anything over 50,000 MPH is most likely interstellar, or at least has a high likelyhood of being so.