Re: Risky asteroid 2009 WM1
promytius":clu7db60 said:
:?: Gosh all that's pretty impressive, but what was that middle part?
I'm just a guy who likes to look at the stars; is there any way you can speak normal English, or point me to a place where all this code will begin to make sense? I'm just as concerned as the next guy - wait, I'll wake him up and ask him - about the sky falling, but after reading through these posts, I'm glad you're watching and I wish I knew what you said about it.
So is there a less technical intro to what you are discussing here that may help me to understand the more technical side of the discussion?
Thanks.
Yeah, I guess even the less technical stuff that we who follow asteroid threads is pretty technical for someone who isn't familiar with the subject.
Basically, the Palermo Scale (PS) is an estimate of the potential damage to earth of an impact compared to the background risk from asteroids we don't know about. It's algorithmic scale, so PS -1 means that there's 10 times less risk from 2009 WM1 compared to the background risk between now and the potential impact in 2018. PS -2 would mean that the risk is 100 times less.
The Torino Scale is for communicating with the general public (2009 WM1 is currently TS1).
I'll copy it here:
No Hazard
(White Zone) 0 The likelihood of a collision is zero, or is so low as to be effectively zero. Also applies to small objects such as meteors and bodies that burn up in the atmosphere as well as infrequent meteorite falls that rarely cause damage.
Normal
(Green Zone) 1 A routine discovery in which a pass near the Earth is predicted that poses no unusual level of danger. Current calculations show the chance of collision is extremely unlikely with no cause for public attention or public concern. New telescopic observations very likely will lead to re-assignment to Level 0.
Meriting Attention by Astronomers
(Yellow Zone) 2 A discovery, which may become routine with expanded searches, of an object making a somewhat close but not highly unusual pass near the Earth. While meriting attention by astronomers, there is no cause for public attention or public concern as an actual collision is very unlikely. New telescopic observations very likely will lead to re-assignment to Level 0.
3 A close encounter, meriting attention by astronomers. Current calculations give a 1% or greater chance of collision capable of localized destruction. Most likely, new telescopic observations will lead to re-assignment to Level 0. Attention by public and by public officials is merited if the encounter is less than a decade away.
4 A close encounter, meriting attention by astronomers. Current calculations give a 1% or greater chance of collision capable of regional devastation. Most likely, new telescopic observations will lead to re-assignment to Level 0. Attention by public and by public officials is merited if the encounter is less than a decade away.
Threatening
(Orange Zone) 5 A close encounter posing a serious, but still uncertain threat of regional devastation. Critical attention by astronomers is needed to determine conclusively whether or not a collision will occur. If the encounter is less than a decade away, governmental contingency planning may be warranted.
6 A close encounter by a large object posing a serious but still uncertain threat of a global catastrophe. Critical attention by astronomers is needed to determine conclusively whether or not a collision will occur. If the encounter is less than three decades away, governmental contingency planning may be warranted.
7 A very close encounter by a large object, which if occurring this century, poses an unprecedented but still uncertain threat of a global catastrophe. For such a threat in this century, international contingency planning is warranted, especially to determine urgently and conclusively whether or not a collision will occur.
Certain Collisions
(Red Zone) 8 A collision is certain, capable of causing localized destruction for an impact over land or possibly a tsunami if close offshore. Such events occur on average between once per 50 years and once per several 1000 years.
9 A collision is certain, capable of causing unprecedented regional devastation for a land impact or the threat of a major tsunami for an ocean impact. Such events occur on average between once per 10,000 years and once per 100,000 years.
10 A collision is certain, capable of causing global climatic catastrophe that may threaten the future of civilization as we know it, whether impacting land or ocean. Such events occur on average once per 100,000 years, or less often.
For a good introduction, read:
http://neo.jpl.nasa.gov/risk/doc/sentry.html
This gives you a basic understanding of the general JPL (Jet Propulsion Lab) Sentry system that we refer to.
The current risk page is here:
http://neo.jpl.nasa.gov/risk/
The other soure we use is NEODyS:
The Near Earth Object Dynamics site:
http://newton.dm.unipi.it/neodys/index.php?pc=4.0
Both of these take the latest observations of Near Earth Objects (asteroids or very rarely, comets) and calculate the orbit to see if they will be at the same place as the earth in the next 100 years or so.
They update daily as new observations come in, which allow more accurate orbits to be calculated.
As far as the really technical stuff like a (semimajor axis), i (inclination of the object orbit in the solar system compared to earth) q (perihelion; closest approach of the object to the sun in it's orbit), Q (aphelion, furthest distance from the sun), etc, that's a bit too much. If you want to learn more about that, do a search on orbits,,and how they are described.
Hope that helps some, please feel free to ask kore question after you read that stuff, or if you just want to ask some quick ones
MW
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