"Shocking" video of comet ISON causes "panic"?!?

[BearOfNH]

A twofer:

 

1. ... The technology to do this does not exist yet. We still don't know the size of C/2012 S1 (ISON), and the initial guesses at a comet's orbit are just that, initial guesses.
2. ... Invoking more magic technology, you find that there's a magical nuclear device that has a mass of but 2500 kg and ...

 

1. By size I assume you mean mass, right? Presumably you can infer mass from observation once you have several points to go on. Isn't a month, or two months, enough time delta? You have what, three or four equations and one unknown?

 

2. I don't know where you got the figure "but 2500 kg" for a nuclear device. The venerable W80 warhead (still in service, cruise missiles mostly) yields 150kt (that's 10+ Hiroshima's) for a warhead mass of 130kg, about 5% of your figure. Wikipedia lists other heavier warheads with correspondingly higher yields. The formula seems to be: yield_kt ~= 1.2*mass_kg. So the W87 booms 300kt for 250kg, and the W88, 475kt at 360kg.

 

Question then becomes: does this affect your calculations for the Delta IV Heavy?

 

[Jupi7er]

If NASA sees a comet this far in advanced they would likely have enough time to plan out a counter measure for when it loops around, but based on the fact that they have made no such attempts it most likely will not hit Earth. There's been closer comets before that have grazed the atmosphere. Besides, it cannot possibly be "globally" visible unless it circles the entire Earth within a day, so if you are monotheistic you'd have to ask why god would give some people a fair warning and others none at all, though you should be asking about a lot more than that in the first place.

I just read that NASA took down its space fence and that it is a major victim of the govt shutdown

its website is down

[swansont]

I just read that NASA took down its space fence and that it is a major victim of the govt shutdown

its website is down

!

Moderator Note

Jupi7er, welcome to SFN. Please try and make your posts pertinent to the discussion going on in the thread, even if the thread is nonsense. Whatever is being discussed here, it's not about the government shutdown, or NASA's website.

[Mr Monkeybat]

Consider that you get pushed back and killed by a piece of metal with less than 1/1000th of your mass. This scenario is only a problem if the rock is loose and the impact will either fragment clearly such that the components keep their original momentum or not transfer enough force to the whole rock.

 

 

Guns kill people by making holes in them. Allot of people get shot without noticing until they find out that the blood on the floor is their own. Guns make holes in people because the force/energy is concentrated, the total amount of energy impacting the shootee is actually less than the recoil experienced by the shooter due exhaust gasses and energy lost to air resistance. Sorry if action films have given you a different impression of stuntmen being yanked by wires.

Edited October 3, 2013 by Mr Monkeybat